feat: Migrate coroutine tests from Boost.Coroutine to C++20 coroutines

Migrate Coroutine_test and JobQueue_test from Boost.Coroutine to
C++20 std::coroutine using CoroTask/CoroTaskRunner:

- Coroutine_test: Replace Coro-based coroutine tests with CoroTask
  equivalents using co_await runner->yieldAndPost().
- JobQueue_test: Replace Coro suspend/resume patterns with CoroTask
  equivalents, use pointer-by-value captures in coroutine lambdas
  to avoid dangling reference issues.

.clang-tidy

@@ -14,6 +14,7 @@ Checks: "-*,
   bugprone-fold-init-type,
   bugprone-forward-declaration-namespace,
   bugprone-inaccurate-erase,
+  bugprone-inc-dec-in-conditions,
   bugprone-incorrect-enable-if,
   bugprone-incorrect-roundings,
   bugprone-infinite-loop,
@@ -64,8 +65,10 @@ Checks: "-*,
   bugprone-undefined-memory-manipulation,
   bugprone-undelegated-constructor,
   bugprone-unhandled-exception-at-new,
+  bugprone-unhandled-self-assignment,
   bugprone-unique-ptr-array-mismatch,
   bugprone-unsafe-functions,
+  bugprone-unused-raii,
   bugprone-unused-local-non-trivial-variable,
   bugprone-virtual-near-miss,
   cppcoreguidelines-no-suspend-with-lock,
@@ -95,12 +98,10 @@ Checks: "-*,
 # checks that have some issues that need to be resolved:
 #
 # bugprone-crtp-constructor-accessibility,
-# bugprone-inc-dec-in-conditions,
 # bugprone-move-forwarding-reference,
 # bugprone-switch-missing-default-case,
 # bugprone-unused-return-value,
 # bugprone-use-after-move,
-# bugprone-unhandled-self-assignment,
 # bugprone-unused-raii,
 #
 # cppcoreguidelines-misleading-capture-default-by-value,

.github/scripts/strategy-matrix/generate.py

@@ -55,7 +55,7 @@ def generate_strategy_matrix(all: bool, config: Config) -> list:
             #   fee to 500.
             # - Bookworm using GCC 15: Debug on linux/amd64, enable code
             #   coverage (which will be done below).
-            # - Bookworm using Clang 16: Debug on linux/arm64, enable voidstar.
+            # - Bookworm using Clang 16: Debug on linux/amd64, enable voidstar.
             # - Bookworm using Clang 17: Release on linux/amd64, set the
             #   reference fee to 1000.
             # - Bookworm using Clang 20: Debug on linux/amd64.
@@ -78,7 +78,7 @@ def generate_strategy_matrix(all: bool, config: Config) -> list:
                     if (
                         f"{os['compiler_name']}-{os['compiler_version']}" == "clang-16"
                         and build_type == "Debug"
-                        and architecture["platform"] == "linux/arm64"
+                        and architecture["platform"] == "linux/amd64"
                     ):
                         cmake_args = f"-Dvoidstar=ON {cmake_args}"
                         skip = False

.github/workflows/on-pr.yml

@@ -141,9 +141,8 @@ jobs:
     needs:
       - should-run
       - build-test
-    # Only run when committing to a PR that targets a release branch in the
-    # XRPLF repository.
-    if: ${{ github.repository_owner == 'XRPLF' && needs.should-run.outputs.go == 'true' && startsWith(github.ref, 'refs/heads/release') }}
+    # Only run when committing to a PR that targets a release branch.
+    if: ${{ github.repository == 'XRPLF/rippled' && needs.should-run.outputs.go == 'true' && startsWith(github.ref, 'refs/heads/release') }}
     uses: ./.github/workflows/reusable-upload-recipe.yml
     secrets:
       remote_username: ${{ secrets.CONAN_REMOTE_USERNAME }}

.github/workflows/on-tag.yml

@@ -17,8 +17,7 @@ defaults:
 
 jobs:
   upload-recipe:
-    # Only run when a tag is pushed to the XRPLF repository.
-    if: ${{ github.repository_owner == 'XRPLF' }}
+    if: ${{ github.repository == 'XRPLF/rippled' }}
     uses: ./.github/workflows/reusable-upload-recipe.yml
     secrets:
       remote_username: ${{ secrets.CONAN_REMOTE_USERNAME }}

.github/workflows/on-trigger.yml

@@ -92,8 +92,8 @@ jobs:
 
   upload-recipe:
     needs: build-test
-    # Only run when pushing to the develop branch in the XRPLF repository.
-    if: ${{ github.repository_owner == 'XRPLF' && github.event_name == 'push' && github.ref == 'refs/heads/develop' }}
+    # Only run when pushing to the develop branch.
+    if: ${{ github.repository == 'XRPLF/rippled' && github.event_name == 'push' && github.ref == 'refs/heads/develop' }}
     uses: ./.github/workflows/reusable-upload-recipe.yml
     secrets:
       remote_username: ${{ secrets.CONAN_REMOTE_USERNAME }}

.github/workflows/reusable-build-test-config.yml

@@ -176,7 +176,7 @@ jobs:
           fi
 
       - name: Upload the binary (Linux)
-        if: ${{ github.repository_owner == 'XRPLF' && runner.os == 'Linux' }}
+        if: ${{ github.repository == 'XRPLF/rippled' && runner.os == 'Linux' }}
         uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
         with:
           name: xrpld-${{ inputs.config_name }}
@@ -266,7 +266,7 @@ jobs:
             --target coverage
 
       - name: Upload coverage report
-        if: ${{ github.repository_owner == 'XRPLF' && !inputs.build_only && env.COVERAGE_ENABLED == 'true' }}
+        if: ${{ github.repository == 'XRPLF/rippled' && !inputs.build_only && env.COVERAGE_ENABLED == 'true' }}
         uses: codecov/codecov-action@671740ac38dd9b0130fbe1cec585b89eea48d3de # v5.5.2
         with:
           disable_search: true

.github/workflows/upload-conan-deps.yml

@@ -103,11 +103,11 @@ jobs:
           sanitizers: ${{ matrix.sanitizers }}
 
       - name: Log into Conan remote
-        if: ${{ github.repository_owner == 'XRPLF' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch') }}
+        if: ${{ github.repository == 'XRPLF/rippled' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch') }}
         run: conan remote login "${CONAN_REMOTE_NAME}" "${{ secrets.CONAN_REMOTE_USERNAME }}" --password "${{ secrets.CONAN_REMOTE_PASSWORD }}"
 
       - name: Upload Conan packages
-        if: ${{ github.repository_owner == 'XRPLF' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch') }}
+        if: ${{ github.repository == 'XRPLF/rippled' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch') }}
         env:
           FORCE_OPTION: ${{ github.event.inputs.force_upload == 'true' && '--force' || '' }}
         run: conan upload "*" --remote="${CONAN_REMOTE_NAME}" --confirm ${FORCE_OPTION}

CMakeLists.txt

@@ -131,7 +131,6 @@ if(coverage)
     include(XrplCov)
 endif()
 
-set(PROJECT_EXPORT_SET XrplExports)
 include(XrplCore)
 include(XrplInstall)
 include(XrplValidatorKeys)

cmake/XrplConfig.cmake

@@ -1,60 +0,0 @@
-include(CMakeFindDependencyMacro)
-# need to represent system dependencies of the lib here
-#[=========================================================[
-  Boost
-#]=========================================================]
-if(static OR APPLE OR MSVC)
-    set(Boost_USE_STATIC_LIBS ON)
-endif()
-set(Boost_USE_MULTITHREADED ON)
-if(static OR MSVC)
-    set(Boost_USE_STATIC_RUNTIME ON)
-else()
-    set(Boost_USE_STATIC_RUNTIME OFF)
-endif()
-find_dependency(
-    Boost
-    COMPONENTS
-    chrono
-    container
-    context
-    coroutine
-    date_time
-    filesystem
-    program_options
-    regex
-    system
-    thread
-)
-#[=========================================================[
-  OpenSSL
-#]=========================================================]
-if(NOT DEFINED OPENSSL_ROOT_DIR)
-    if(DEFINED ENV{OPENSSL_ROOT})
-        set(OPENSSL_ROOT_DIR $ENV{OPENSSL_ROOT})
-    elseif(APPLE)
-        find_program(homebrew brew)
-        if(homebrew)
-            execute_process(
-                COMMAND ${homebrew} --prefix openssl
-                OUTPUT_VARIABLE OPENSSL_ROOT_DIR
-                OUTPUT_STRIP_TRAILING_WHITESPACE
-            )
-        endif()
-    endif()
-    file(TO_CMAKE_PATH "${OPENSSL_ROOT_DIR}" OPENSSL_ROOT_DIR)
-endif()
-
-if(static OR APPLE OR MSVC)
-    set(OPENSSL_USE_STATIC_LIBS ON)
-endif()
-set(OPENSSL_MSVC_STATIC_RT ON)
-find_dependency(OpenSSL REQUIRED)
-find_dependency(ZLIB)
-find_dependency(date)
-if(TARGET ZLIB::ZLIB)
-    set_target_properties(
-        OpenSSL::Crypto
-        PROPERTIES INTERFACE_LINK_LIBRARIES ZLIB::ZLIB
-    )
-endif()

cmake/XrplInstall.cmake

@@ -2,100 +2,38 @@
    install stuff
 #]===================================================================]
 
-include(create_symbolic_link)
+include(GNUInstallDirs)
 
-# If no suffix is defined for executables (e.g. Windows uses .exe but Linux
-# and macOS use none), then explicitly set it to the empty string.
-if(NOT DEFINED suffix)
-    set(suffix "")
+if(is_root_project AND TARGET xrpld)
+    install(
+        TARGETS xrpld
+        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT runtime
+    )
+
+    install(
+        FILES "${CMAKE_CURRENT_SOURCE_DIR}/cfg/xrpld-example.cfg"
+        DESTINATION "${CMAKE_INSTALL_SYSCONFDIR}/xrpld"
+        RENAME xrpld.cfg
+        COMPONENT runtime
+    )
+
+    install(
+        FILES "${CMAKE_CURRENT_SOURCE_DIR}/cfg/validators-example.txt"
+        DESTINATION "${CMAKE_INSTALL_SYSCONFDIR}/xrpld"
+        RENAME validators.txt
+        COMPONENT runtime
+    )
 endif()
 
 install(
-    TARGETS
-        common
-        opts
-        xrpl_boost
-        xrpl_libs
-        xrpl_syslibs
-        xrpl.imports.main
-        xrpl.libpb
-        xrpl.libxrpl
-        xrpl.libxrpl.basics
-        xrpl.libxrpl.beast
-        xrpl.libxrpl.conditions
-        xrpl.libxrpl.core
-        xrpl.libxrpl.crypto
-        xrpl.libxrpl.git
-        xrpl.libxrpl.json
-        xrpl.libxrpl.rdb
-        xrpl.libxrpl.ledger
-        xrpl.libxrpl.net
-        xrpl.libxrpl.nodestore
-        xrpl.libxrpl.protocol
-        xrpl.libxrpl.resource
-        xrpl.libxrpl.server
-        xrpl.libxrpl.shamap
-        xrpl.libxrpl.tx
-        antithesis-sdk-cpp
-    EXPORT XrplExports
-    LIBRARY DESTINATION lib
-    ARCHIVE DESTINATION lib
-    RUNTIME DESTINATION bin
-    INCLUDES DESTINATION include
+    TARGETS xrpl.libpb xrpl.libxrpl
+    LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT development
+    ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT development
+    RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT development
 )
 
 install(
     DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/include/xrpl"
     DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
-)
-
-install(
-    EXPORT XrplExports
-    FILE XrplTargets.cmake
-    NAMESPACE Xrpl::
-    DESTINATION lib/cmake/xrpl
-)
-include(CMakePackageConfigHelpers)
-write_basic_package_version_file(
-    XrplConfigVersion.cmake
-    VERSION ${xrpld_version}
-    COMPATIBILITY SameMajorVersion
-)
-
-if(is_root_project AND TARGET xrpld)
-    install(TARGETS xrpld RUNTIME DESTINATION bin)
-    set_target_properties(xrpld PROPERTIES INSTALL_RPATH_USE_LINK_PATH ON)
-    # sample configs should not overwrite existing files
-    # install if-not-exists workaround as suggested by
-    # https://cmake.org/Bug/view.php?id=12646
-    install(
-        CODE
-            "
-    macro (copy_if_not_exists SRC DEST NEWNAME)
-      if (NOT EXISTS \"\$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/\${DEST}/\${NEWNAME}\")
-        file (INSTALL FILE_PERMISSIONS OWNER_READ OWNER_WRITE DESTINATION \"\${CMAKE_INSTALL_PREFIX}/\${DEST}\" FILES \"\${SRC}\" RENAME \"\${NEWNAME}\")
-      else ()
-        message (\"-- Skipping : \$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/\${DEST}/\${NEWNAME}\")
-      endif ()
-    endmacro()
-    copy_if_not_exists(\"${CMAKE_CURRENT_SOURCE_DIR}/cfg/xrpld-example.cfg\" etc xrpld.cfg)
-    copy_if_not_exists(\"${CMAKE_CURRENT_SOURCE_DIR}/cfg/validators-example.txt\" etc validators.txt)
-  "
-    )
-    install(
-        CODE
-            "
-    set(CMAKE_MODULE_PATH \"${CMAKE_MODULE_PATH}\")
-    include(create_symbolic_link)
-    create_symbolic_link(xrpld${suffix} \
-       \$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}/rippled${suffix})
-  "
-    )
-endif()
-
-install(
-    FILES
-        ${CMAKE_CURRENT_SOURCE_DIR}/cmake/XrplConfig.cmake
-        ${CMAKE_CURRENT_BINARY_DIR}/XrplConfigVersion.cmake
-    DESTINATION lib/cmake/xrpl
+    COMPONENT development
 )

cmake/XrplSanity.cmake

@@ -50,6 +50,13 @@ if(MSVC AND CMAKE_GENERATOR_PLATFORM STREQUAL "Win32")
     message(FATAL_ERROR "Visual Studio 32-bit build is not supported.")
 endif()
 
+if(voidstar AND NOT is_amd64)
+    message(
+        FATAL_ERROR
+        "The voidstar library only supported on amd64/x86_64. Detected archictecture was: ${CMAKE_SYSTEM_PROCESSOR}"
+    )
+endif()
+
 if(APPLE AND NOT HOMEBREW)
     find_program(HOMEBREW brew)
 endif()

cspell.config.yaml

@@ -71,12 +71,14 @@ words:
   - coldwallet
   - compr
   - conanfile
+  - cppcoro
   - conanrun
   - confs
   - connectability
   - coro
   - coros
   - cowid
+  - cppcoro
   - cryptocondition
   - cryptoconditional
   - cryptoconditions
@@ -99,11 +101,14 @@ words:
   - endmacro
   - exceptioned
   - Falco
+  - fcontext
   - finalizers
   - firewalled
+  - fcontext
   - fmtdur
   - fsanitize
   - funclets
+  - gantt
   - gcov
   - gcovr
   - ghead
@@ -187,6 +192,7 @@ words:
   - ostr
   - pargs
   - partitioner
+  - pratik
   - paychan
   - paychans
   - permdex
@@ -194,6 +200,7 @@ words:
   - permissioned
   - pointee
   - populator
+  - pratik
   - preauth
   - preauthorization
   - preauthorize
@@ -208,6 +215,7 @@ words:
   - queuable
   - Raphson
   - replayer
+  - repost
   - rerere
   - retriable
   - RIPD
@@ -238,6 +246,7 @@ words:
   - soci
   - socidb
   - sslws
+  - stackful
   - statsd
   - STATSDCOLLECTOR
   - stissue

include/xrpl/core/CoroTask.h

@@ -0,0 +1,699 @@
+#pragma once
+
+#include <xrpl/beast/utility/instrumentation.h>
+
+#include <coroutine>
+#include <exception>
+#include <type_traits>
+#include <utility>
+#include <variant>
+
+namespace xrpl {
+
+template <typename T = void>
+class CoroTask;
+
+/**
+ * CoroTask<void> -- coroutine return type for void-returning coroutines.
+ *
+ * Class / Dependency Diagram
+ * ==========================
+ *
+ *   CoroTask<void>
+ *   +-----------------------------------------------+
+ *   | - handle_ : Handle (coroutine_handle<promise>) |
+ *   +-----------------------------------------------+
+ *   | + handle(), done()                             |
+ *   | + await_ready/suspend/resume  (Awaiter iface)  |
+ *   +-----------------------------------------------+
+ *            |  owns
+ *            v
+ *   promise_type
+ *   +-----------------------------------------------+
+ *   | - exception_    : std::exception_ptr           |
+ *   | - continuation_ : std::coroutine_handle<>      |
+ *   +-----------------------------------------------+
+ *   | + get_return_object() -> CoroTask              |
+ *   | + initial_suspend()   -> suspend_always (lazy) |
+ *   | + final_suspend()     -> FinalAwaiter          |
+ *   | + return_void()                                |
+ *   | + unhandled_exception()                        |
+ *   +-----------------------------------------------+
+ *            |  returns at final_suspend
+ *            v
+ *   FinalAwaiter
+ *   +-----------------------------------------------+
+ *   | await_suspend(h):                              |
+ *   |   if continuation_ set -> symmetric transfer   |
+ *   |   else                 -> noop_coroutine        |
+ *   +-----------------------------------------------+
+ *
+ * Design Notes
+ * ------------
+ * - Lazy start: initial_suspend returns suspend_always, so the coroutine
+ *   body does not execute until the handle is explicitly resumed.
+ * - Symmetric transfer: await_suspend returns a coroutine_handle instead
+ *   of void/bool, allowing the scheduler to jump directly to the next
+ *   coroutine without growing the call stack.
+ * - Continuation chaining: when one CoroTask is co_await-ed inside
+ *   another, the caller's handle is stored as continuation_ so
+ *   FinalAwaiter can resume it when this task finishes.
+ * - Move-only: the handle is exclusively owned; copy is deleted.
+ *
+ * Usage Examples
+ * ==============
+ *
+ * 1. Basic void coroutine (the most common case in rippled):
+ *
+ *      CoroTask<void> doWork(std::shared_ptr<CoroTaskRunner> runner) {
+ *          // do something
+ *          co_await runner->suspend();   // yield control
+ *          // resumed later via runner->post() or runner->resume()
+ *          co_return;
+ *      }
+ *
+ * 2. co_await-ing one CoroTask<void> from another (chaining):
+ *
+ *      CoroTask<void> inner() {
+ *          // ...
+ *          co_return;
+ *      }
+ *      CoroTask<void> outer() {
+ *          co_await inner();   // continuation_ links outer -> inner
+ *          co_return;          // FinalAwaiter resumes outer
+ *      }
+ *
+ * 3. Exceptions propagate through co_await:
+ *
+ *      CoroTask<void> failing() {
+ *          throw std::runtime_error("oops");
+ *          co_return;
+ *      }
+ *      CoroTask<void> caller() {
+ *          try { co_await failing(); }
+ *          catch (std::runtime_error const&) { // caught here }
+ *      }
+ *
+ * Caveats / Pitfalls
+ * ==================
+ *
+ * BUG-RISK: Dangling references in coroutine parameters.
+ *   Coroutine parameters are copied into the frame, but references
+ *   are NOT -- they are stored as-is. If the referent goes out of scope
+ *   before the coroutine finishes, you get use-after-free.
+ *
+ *      // BROKEN -- local dies before coroutine runs:
+ *      CoroTask<void> bad(int& ref) { co_return; }
+ *      void launch() {
+ *          int local = 42;
+ *          auto task = bad(local);  // frame stores &local
+ *      }  // local destroyed; frame holds dangling ref
+ *
+ *      // FIX -- pass by value, or ensure lifetime via shared_ptr.
+ *
+ * BUG-RISK: GCC 14 corrupts reference captures in coroutine lambdas.
+ *   When a lambda that returns CoroTask captures by reference ([&]),
+ *   GCC 14 may generate a corrupted coroutine frame. Always capture
+ *   by explicit pointer-to-value instead:
+ *
+ *      // BROKEN on GCC 14:
+ *      jq.postCoroTask(t, n, [&](auto) -> CoroTask<void> { ... });
+ *
+ *      // FIX -- capture pointers explicitly:
+ *      jq.postCoroTask(t, n, [ptr = &val](auto) -> CoroTask<void> { ... });
+ *
+ * BUG-RISK: Resuming a destroyed or completed CoroTask.
+ *   Calling handle().resume() after the coroutine has already run to
+ *   completion (done() == true) is undefined behavior. The CoroTaskRunner
+ *   guards against this with an XRPL_ASSERT, but standalone usage of
+ *   CoroTask must check done() before resuming.
+ *
+ * BUG-RISK: Moving a CoroTask that is being awaited.
+ *   If task A is co_await-ed by task B (so A.continuation_ == B), moving
+ *   or destroying A will invalidate the continuation link. Never move
+ *   or reassign a CoroTask while it is mid-execution or being awaited.
+ *
+ * LIMITATION: CoroTask is fire-and-forget for the top-level owner.
+ *   There is no built-in notification when the coroutine finishes.
+ *   The caller must use external synchronization (e.g. CoroTaskRunner::join
+ *   or a gate/condition_variable) to know when it is done.
+ *
+ * LIMITATION: No cancellation token.
+ *   There is no way to cancel a suspended CoroTask from outside. The
+ *   coroutine body must cooperatively check a flag (e.g. jq_.isStopping())
+ *   after each co_await and co_return early if needed.
+ *
+ * LIMITATION: Stackless -- cannot suspend from nested non-coroutine calls.
+ *   If a coroutine calls a regular function that wants to "yield", it
+ *   cannot. Only the immediate coroutine body can use co_await.
+ *   This is acceptable for rippled because all yield() sites are shallow.
+ */
+template <>
+class CoroTask<void>
+{
+public:
+    struct promise_type;
+    using Handle = std::coroutine_handle<promise_type>;
+
+    /**
+     * Coroutine promise. Compiler uses this to manage coroutine state.
+     * Stores the exception (if any) and the continuation handle for
+     * symmetric transfer back to the awaiting coroutine.
+     */
+    struct promise_type
+    {
+        // Captured exception from the coroutine body, rethrown in
+        // await_resume() when this task is co_await-ed by a caller.
+        std::exception_ptr exception_;
+
+        // Handle to the coroutine that is co_await-ing this task.
+        // Set by await_suspend(). FinalAwaiter uses it for symmetric
+        // transfer back to the caller. Null if this is a top-level task.
+        std::coroutine_handle<> continuation_;
+
+        /**
+         * Create the CoroTask return object.
+         * Called by the compiler at coroutine creation.
+         */
+        CoroTask
+        get_return_object()
+        {
+            return CoroTask{Handle::from_promise(*this)};
+        }
+
+        /**
+         * Lazy start. The coroutine body does not execute until the
+         * handle is explicitly resumed (e.g. by CoroTaskRunner::resume).
+         */
+        std::suspend_always
+        initial_suspend() noexcept
+        {
+            return {};
+        }
+
+        /**
+         * Awaiter returned by final_suspend(). Uses symmetric transfer:
+         * if a continuation exists, transfers control directly to it
+         * (tail-call, no stack growth). Otherwise returns noop_coroutine
+         * so the coroutine frame stays alive for the owner to destroy.
+         */
+        struct FinalAwaiter
+        {
+            /**
+             * Always false. We need await_suspend to run for
+             * symmetric transfer.
+             */
+            bool
+            await_ready() noexcept
+            {
+                return false;
+            }
+
+            /**
+             * Symmetric transfer: returns the continuation handle so
+             * the compiler emits a tail-call instead of a nested resume.
+             * If no continuation is set, returns noop_coroutine to
+             * suspend at final_suspend without destroying the frame.
+             *
+             * @param h Handle to this completing coroutine
+             *
+             * @return Continuation handle, or noop_coroutine
+             */
+            std::coroutine_handle<>
+            await_suspend(Handle h) noexcept
+            {
+                if (auto cont = h.promise().continuation_)
+                    return cont;
+                return std::noop_coroutine();
+            }
+
+            void
+            await_resume() noexcept
+            {
+            }
+        };
+
+        /**
+         * Returns FinalAwaiter for symmetric transfer at coroutine end.
+         */
+        FinalAwaiter
+        final_suspend() noexcept
+        {
+            return {};
+        }
+
+        /**
+         * Called by the compiler for `co_return;` (void coroutine).
+         */
+        void
+        return_void()
+        {
+        }
+
+        /**
+         * Called by the compiler when an exception escapes the coroutine
+         * body. Captures it for later rethrowing in await_resume().
+         */
+        void
+        unhandled_exception()
+        {
+            exception_ = std::current_exception();
+        }
+    };
+
+    /**
+     * Default constructor. Creates an empty (null handle) task.
+     */
+    CoroTask() = default;
+
+    /**
+     * Takes ownership of a compiler-generated coroutine handle.
+     *
+     * @param h Coroutine handle to own
+     */
+    explicit CoroTask(Handle h) : handle_(h)
+    {
+    }
+
+    /**
+     * Destroys the coroutine frame if this task owns one.
+     */
+    ~CoroTask()
+    {
+        if (handle_)
+            handle_.destroy();
+    }
+
+    /**
+     * Move constructor. Transfers handle ownership, leaves other empty.
+     */
+    CoroTask(CoroTask&& other) noexcept : handle_(std::exchange(other.handle_, {}))
+    {
+    }
+
+    /**
+     * Move assignment. Destroys current frame (if any), takes other's.
+     */
+    CoroTask&
+    operator=(CoroTask&& other) noexcept
+    {
+        if (this != &other)
+        {
+            if (handle_)
+                handle_.destroy();
+            handle_ = std::exchange(other.handle_, {});
+        }
+        return *this;
+    }
+
+    CoroTask(CoroTask const&) = delete;
+    CoroTask&
+    operator=(CoroTask const&) = delete;
+
+    /**
+     * @return The underlying coroutine_handle
+     */
+    Handle
+    handle() const
+    {
+        return handle_;
+    }
+
+    /**
+     * @return true if the coroutine has run to completion (or thrown)
+     */
+    bool
+    done() const
+    {
+        return handle_ && handle_.done();
+    }
+
+    // -- Awaiter interface: allows `co_await someCoroTask;` --
+
+    /**
+     * Always false. This task is lazy, so co_await always suspends
+     * the caller to set up the continuation link.
+     */
+    bool
+    await_ready() const noexcept
+    {
+        return false;
+    }
+
+    /**
+     * Stores the caller's handle as our continuation, then returns
+     * our handle for symmetric transfer (caller suspends, we resume).
+     *
+     * @param caller Handle of the coroutine doing co_await on us
+     *
+     * @return Our handle for symmetric transfer
+     */
+    std::coroutine_handle<>
+    await_suspend(std::coroutine_handle<> caller) noexcept
+    {
+        XRPL_ASSERT(handle_, "xrpl::CoroTask<void>::await_suspend : handle is valid");
+        handle_.promise().continuation_ = caller;
+        return handle_;  // Symmetric transfer
+    }
+
+    /**
+     * Called in the awaiting coroutine's context after this task
+     * completes. Rethrows any exception captured by
+     * unhandled_exception().
+     */
+    void
+    await_resume()
+    {
+        XRPL_ASSERT(handle_, "xrpl::CoroTask<void>::await_resume : handle is valid");
+        if (auto& ep = handle_.promise().exception_)
+            std::rethrow_exception(ep);
+    }
+
+private:
+    // Exclusively-owned coroutine handle. Null after move or default
+    // construction. Destroyed in the destructor.
+    Handle handle_;
+};
+
+/**
+ * CoroTask<T> -- coroutine return type for value-returning coroutines.
+ *
+ * Class / Dependency Diagram
+ * ==========================
+ *
+ *   CoroTask<T>
+ *   +-----------------------------------------------+
+ *   | - handle_ : Handle (coroutine_handle<promise>) |
+ *   +-----------------------------------------------+
+ *   | + handle(), done()                             |
+ *   | + await_ready/suspend/resume  (Awaiter iface)  |
+ *   +-----------------------------------------------+
+ *            |  owns
+ *            v
+ *   promise_type
+ *   +-----------------------------------------------+
+ *   | - result_       : variant<monostate, T,        |
+ *   |                           exception_ptr>       |
+ *   | - continuation_ : std::coroutine_handle<>      |
+ *   +-----------------------------------------------+
+ *   | + get_return_object() -> CoroTask              |
+ *   | + initial_suspend()   -> suspend_always (lazy) |
+ *   | + final_suspend()     -> FinalAwaiter          |
+ *   | + return_value(T)     -> stores in result_[1]  |
+ *   | + unhandled_exception -> stores in result_[2]  |
+ *   +-----------------------------------------------+
+ *            |  returns at final_suspend
+ *            v
+ *   FinalAwaiter  (same symmetric-transfer pattern as CoroTask<void>)
+ *
+ * Value Extraction
+ * ----------------
+ * await_resume() inspects the variant:
+ *   - index 2 (exception_ptr) -> rethrow
+ *   - index 1 (T)             -> return value via move
+ *
+ * Usage Examples
+ * ==============
+ *
+ * 1. Simple value return:
+ *
+ *      CoroTask<int> computeAnswer() { co_return 42; }
+ *
+ *      CoroTask<void> caller() {
+ *          int v = co_await computeAnswer();  // v == 42
+ *      }
+ *
+ * 2. Chaining value-returning coroutines:
+ *
+ *      CoroTask<int> add(int a, int b) { co_return a + b; }
+ *      CoroTask<int> doubleSum(int a, int b) {
+ *          int s = co_await add(a, b);
+ *          co_return s * 2;
+ *      }
+ *
+ * 3. Exception propagation from inner to outer:
+ *
+ *      CoroTask<int> failing() {
+ *          throw std::runtime_error("bad");
+ *          co_return 0;  // never reached
+ *      }
+ *      CoroTask<void> caller() {
+ *          try {
+ *              int v = co_await failing();  // throws here
+ *          } catch (std::runtime_error const& e) {
+ *              // e.what() == "bad"
+ *          }
+ *      }
+ *
+ * Caveats / Pitfalls (in addition to CoroTask<void> caveats above)
+ * ================================================================
+ *
+ * BUG-RISK: await_resume() moves the value out of the variant.
+ *   Calling co_await on the same CoroTask<T> instance twice is undefined
+ *   behavior -- the second call will see a moved-from T. CoroTask is
+ *   single-shot: one co_return, one co_await.
+ *
+ * BUG-RISK: T must be move-constructible.
+ *   return_value(T) takes by value and moves into the variant.
+ *   Types that are not movable cannot be used as T.
+ *
+ * LIMITATION: No co_yield support.
+ *   CoroTask<T> only supports a single co_return. It does not implement
+ *   yield_value(), so using co_yield inside a CoroTask<T> coroutine is a
+ *   compile error. For streaming values, a different return type
+ *   (e.g. Generator<T>) would be needed.
+ *
+ * LIMITATION: Result is only accessible via co_await.
+ *   There is no .get() or .result() method. The value can only be
+ *   extracted by co_await-ing the CoroTask<T> from inside another
+ *   coroutine. For extracting results in non-coroutine code, pass a
+ *   pointer to the caller and write through it (as the tests do).
+ */
+template <typename T>
+class CoroTask
+{
+    static_assert(
+        std::is_move_constructible_v<T>,
+        "CoroTask<T> requires T to be move-constructible");
+
+public:
+    struct promise_type;
+    using Handle = std::coroutine_handle<promise_type>;
+
+    /**
+     * Coroutine promise for value-returning coroutines.
+     * Stores the result as a variant: monostate (not yet set),
+     * T (co_return value), or exception_ptr (unhandled exception).
+     */
+    struct promise_type
+    {
+        // Tri-state result:
+        //   index 0 (monostate) -- coroutine has not yet completed
+        //   index 1 (T)         -- co_return value stored here
+        //   index 2 (exception) -- unhandled exception captured here
+        std::variant<std::monostate, T, std::exception_ptr> result_;
+
+        // Handle to the coroutine co_await-ing this task. Used by
+        // FinalAwaiter for symmetric transfer. Null for top-level tasks.
+        std::coroutine_handle<> continuation_;
+
+        /**
+         * Create the CoroTask return object.
+         * Called by the compiler at coroutine creation.
+         */
+        CoroTask
+        get_return_object()
+        {
+            return CoroTask{Handle::from_promise(*this)};
+        }
+
+        /**
+         * Lazy start. Coroutine body does not run until explicitly resumed.
+         */
+        std::suspend_always
+        initial_suspend() noexcept
+        {
+            return {};
+        }
+
+        /**
+         * Symmetric-transfer awaiter at coroutine completion.
+         * Same pattern as CoroTask<void>::FinalAwaiter.
+         */
+        struct FinalAwaiter
+        {
+            bool
+            await_ready() noexcept
+            {
+                return false;
+            }
+
+            /**
+             * Returns continuation for symmetric transfer, or
+             * noop_coroutine if this is a top-level task.
+             *
+             * @param h Handle to this completing coroutine
+             *
+             * @return Continuation handle, or noop_coroutine
+             */
+            std::coroutine_handle<>
+            await_suspend(Handle h) noexcept
+            {
+                if (auto cont = h.promise().continuation_)
+                    return cont;
+                return std::noop_coroutine();
+            }
+
+            void
+            await_resume() noexcept
+            {
+            }
+        };
+
+        FinalAwaiter
+        final_suspend() noexcept
+        {
+            return {};
+        }
+
+        /**
+         * Called by the compiler for `co_return value;`.
+         * Moves the value into result_ at index 1.
+         *
+         * @param value The value to store
+         */
+        void
+        return_value(T value)
+        {
+            result_.template emplace<1>(std::move(value));
+        }
+
+        /**
+         * Captures unhandled exceptions at index 2 of result_.
+         * Rethrown later in await_resume().
+         */
+        void
+        unhandled_exception()
+        {
+            result_.template emplace<2>(std::current_exception());
+        }
+    };
+
+    /**
+     * Default constructor. Creates an empty (null handle) task.
+     */
+    CoroTask() = default;
+
+    /**
+     * Takes ownership of a compiler-generated coroutine handle.
+     *
+     * @param h Coroutine handle to own
+     */
+    explicit CoroTask(Handle h) : handle_(h)
+    {
+    }
+
+    /**
+     * Destroys the coroutine frame if this task owns one.
+     */
+    ~CoroTask()
+    {
+        if (handle_)
+            handle_.destroy();
+    }
+
+    /**
+     * Move constructor. Transfers handle ownership, leaves other empty.
+     */
+    CoroTask(CoroTask&& other) noexcept : handle_(std::exchange(other.handle_, {}))
+    {
+    }
+
+    /**
+     * Move assignment. Destroys current frame (if any), takes other's.
+     */
+    CoroTask&
+    operator=(CoroTask&& other) noexcept
+    {
+        if (this != &other)
+        {
+            if (handle_)
+                handle_.destroy();
+            handle_ = std::exchange(other.handle_, {});
+        }
+        return *this;
+    }
+
+    CoroTask(CoroTask const&) = delete;
+    CoroTask&
+    operator=(CoroTask const&) = delete;
+
+    /**
+     * @return The underlying coroutine_handle
+     */
+    Handle
+    handle() const
+    {
+        return handle_;
+    }
+
+    /**
+     * @return true if the coroutine has run to completion (or thrown)
+     */
+    bool
+    done() const
+    {
+        return handle_ && handle_.done();
+    }
+
+    // -- Awaiter interface: allows `T val = co_await someCoroTask;` --
+
+    /**
+     * Always false. co_await always suspends to set up continuation.
+     */
+    bool
+    await_ready() const noexcept
+    {
+        return false;
+    }
+
+    /**
+     * Stores caller as continuation, returns our handle for
+     * symmetric transfer.
+     *
+     * @param caller Handle of the coroutine doing co_await on us
+     *
+     * @return Our handle for symmetric transfer
+     */
+    std::coroutine_handle<>
+    await_suspend(std::coroutine_handle<> caller) noexcept
+    {
+        XRPL_ASSERT(handle_, "xrpl::CoroTask<T>::await_suspend : handle is valid");
+        handle_.promise().continuation_ = caller;
+        return handle_;
+    }
+
+    /**
+     * Extracts the result: rethrows if exception, otherwise moves
+     * the T value out of the variant. Single-shot: calling twice
+     * on the same task is undefined (moved-from T).
+     *
+     * @return The co_return-ed value
+     */
+    T
+    await_resume()
+    {
+        XRPL_ASSERT(handle_, "xrpl::CoroTask<T>::await_resume : handle is valid");
+        auto& result = handle_.promise().result_;
+        if (auto* ep = std::get_if<2>(&result))
+            std::rethrow_exception(*ep);
+        return std::get<1>(std::move(result));
+    }
+
+private:
+    // Exclusively-owned coroutine handle. Null after move or default
+    // construction. Destroyed in the destructor.
+    Handle handle_;
+};
+
+}  // namespace xrpl

include/xrpl/core/CoroTaskRunner.ipp

@@ -0,0 +1,374 @@
+#pragma once
+
+/**
+ * @file CoroTaskRunner.ipp
+ *
+ * CoroTaskRunner inline implementation.
+ *
+ * This file contains the business logic for managing C++20 coroutines
+ * on the JobQueue. It is included at the bottom of JobQueue.h.
+ *
+ * Data Flow: suspend / post / resume cycle
+ * =========================================
+ *
+ *         coroutine body                 CoroTaskRunner              JobQueue
+ *         --------------                 --------------              --------
+ *              |
+ *    co_await runner->suspend()
+ *              |
+ *              +--- await_suspend ------> onSuspend()
+ *              |                            ++nSuspend_ ------------> nSuspend_
+ *              |                          [coroutine is now suspended]
+ *              |
+ *              .    (externally or by yieldAndPost())
+ *              .
+ *              +--- (caller calls) -----> post()
+ *              |                            ++runCount_
+ *              |                            addJob(resume) ----------> job enqueued
+ *              |                                                        |
+ *              |                                                      [worker picks up]
+ *              |                                                        |
+ *              +--- <----- resume() <-----------------------------------+
+ *              |             --nSuspend_ ------> nSuspend_
+ *              |             swap in LocalValues (lvs_)
+ *              |             task_.handle().resume()
+ *              |                |
+ *              |    [coroutine body continues here]
+ *              |                |
+ *              |             swap out LocalValues
+ *              |             --runCount_
+ *              |             cv_.notify_all()
+ *              v
+ *
+ * Thread Safety
+ * =============
+ * - mutex_     : guards task_.handle().resume() so that post()-before-suspend
+ *                races cannot resume the coroutine while it is still running.
+ *                (See the race condition discussion in JobQueue.h)
+ * - mutex_run_ : guards runCount_ counter; used by join() to wait until
+ *                all in-flight resume operations complete.
+ * - jq_.m_mutex: guards nSuspend_ increments/decrements.
+ *
+ * Common Mistakes When Modifying This File
+ * =========================================
+ *
+ * 1. Changing lock ordering.
+ *    resume() acquires locks sequentially (never held simultaneously):
+ *    jq_.m_mutex (released immediately), then mutex_ (held across resume),
+ *    then mutex_run_ (released after decrement). post() acquires only
+ *    mutex_run_. Any new code path must follow the same order.
+ *
+ * 2. Removing the shared_from_this() capture in post().
+ *    The lambda passed to addJob captures [this, sp = shared_from_this()].
+ *    If you remove sp, 'this' can be destroyed before the job runs,
+ *    causing use-after-free. The sp capture is load-bearing.
+ *
+ * 3. Forgetting to decrement nSuspend_ on a new code path.
+ *    Every ++nSuspend_ must have a matching --nSuspend_. If you add a new
+ *    suspension path (e.g. a new awaiter) and forget to decrement on resume
+ *    or on failure, JobQueue::stop() will hang.
+ *
+ * 4. Calling task_.handle().resume() without holding mutex_.
+ *    This allows a race where the coroutine runs on two threads
+ *    simultaneously. Always hold mutex_ around resume().
+ *
+ * 5. Swapping LocalValues outside of the mutex_ critical section.
+ *    The swap-in and swap-out of LocalValues must bracket the resume()
+ *    call. If you move the swap-out before the lock_guard(mutex_) is
+ *    released, you break LocalValue isolation for any code that runs
+ *    after the coroutine suspends but before the lock is dropped.
+ */
+
+namespace xrpl {
+
+/**
+ * Construct a CoroTaskRunner. Sets runCount_ to 0; does not
+ * create the coroutine. Call init() afterwards.
+ *
+ * @param jq   The JobQueue this coroutine will run on
+ * @param type Job type for scheduling priority
+ * @param name Human-readable name for logging
+ */
+inline JobQueue::CoroTaskRunner::CoroTaskRunner(
+    create_t,
+    JobQueue& jq,
+    JobType type,
+    std::string const& name)
+    : jq_(jq), type_(type), name_(name), runCount_(0)
+{
+}
+
+/**
+ * Initialize with a coroutine-returning callable.
+ * Stores the callable on the heap (FuncStore) so it outlives the
+ * coroutine frame. Coroutine frames store a reference to the
+ * callable's implicit object parameter (the lambda). If the callable
+ * is a temporary, that reference dangles after the caller returns.
+ * Keeping the callable alive here ensures the coroutine's captures
+ * remain valid.
+ *
+ * @param f Callable: CoroTask<void>(shared_ptr<CoroTaskRunner>)
+ */
+template <class F>
+void
+JobQueue::CoroTaskRunner::init(F&& f)
+{
+    using Fn = std::decay_t<F>;
+    auto store = std::make_unique<FuncStore<Fn>>(std::forward<F>(f));
+    task_ = store->func(shared_from_this());
+    storedFunc_ = std::move(store);
+}
+
+/**
+ * Destructor. Waits for any in-flight resume() to complete, then
+ * asserts (debug) that the coroutine has finished or
+ * expectEarlyExit() was called.
+ *
+ * The join() call is necessary because with async dispatch the
+ * coroutine runs on a worker thread. The gate signal (which wakes
+ * the test thread) can arrive before resume() has set finished_.
+ * join() synchronizes via mutex_run_, establishing a happens-before
+ * edge: finished_ = true -> unlock(mutex_run_) in resume() ->
+ * lock(mutex_run_) in join() -> read finished_.
+ */
+inline JobQueue::CoroTaskRunner::~CoroTaskRunner()
+{
+#ifndef NDEBUG
+    join();
+    XRPL_ASSERT(finished_, "xrpl::JobQueue::CoroTaskRunner::~CoroTaskRunner : is finished");
+#endif
+}
+
+/**
+ * Increment the JobQueue's suspended-coroutine count (nSuspend_).
+ */
+inline void
+JobQueue::CoroTaskRunner::onSuspend()
+{
+    std::lock_guard lock(jq_.m_mutex);
+    ++jq_.nSuspend_;
+}
+
+/**
+ * Decrement nSuspend_ without resuming.
+ */
+inline void
+JobQueue::CoroTaskRunner::onUndoSuspend()
+{
+    std::lock_guard lock(jq_.m_mutex);
+    --jq_.nSuspend_;
+}
+
+/**
+ * Return a SuspendAwaiter whose await_suspend() increments nSuspend_
+ * before the coroutine actually suspends. The caller must later call
+ * post() or resume() to continue execution.
+ *
+ * @return Awaiter for use with `co_await runner->suspend()`
+ */
+inline auto
+JobQueue::CoroTaskRunner::suspend()
+{
+    /**
+     * Custom awaiter for suspend(). Always suspends (await_ready
+     * returns false) and increments nSuspend_ in await_suspend().
+     */
+    struct SuspendAwaiter
+    {
+        CoroTaskRunner& runner_;  // The runner that owns this coroutine.
+
+        /**
+         * Always returns false so the coroutine suspends.
+         */
+        bool
+        await_ready() const noexcept
+        {
+            return false;
+        }
+
+        /**
+         * Called when the coroutine suspends. Increments nSuspend_
+         * so the JobQueue knows a coroutine is waiting.
+         */
+        void
+        await_suspend(std::coroutine_handle<>) const
+        {
+            runner_.onSuspend();
+        }
+
+        void
+        await_resume() const noexcept
+        {
+        }
+    };
+    return SuspendAwaiter{*this};
+}
+
+/**
+ * Suspend and immediately repost on the JobQueue. Equivalent to
+ * `co_await JobQueueAwaiter{runner}` but uses an inline struct
+ * to work around a GCC-12 codegen bug (see declaration in JobQueue.h).
+ *
+ * If the JobQueue is stopping (post fails), the suspend count is
+ * undone and the coroutine is resumed immediately via h.resume().
+ *
+ * @return An inline YieldPostAwaiter
+ */
+inline auto
+JobQueue::CoroTaskRunner::yieldAndPost()
+{
+    struct YieldPostAwaiter
+    {
+        CoroTaskRunner& runner_;
+
+        bool
+        await_ready() const noexcept
+        {
+            return false;
+        }
+
+        void
+        await_suspend(std::coroutine_handle<> h)
+        {
+            runner_.onSuspend();
+            if (!runner_.post())
+            {
+                runner_.onUndoSuspend();
+                h.resume();
+            }
+        }
+
+        void
+        await_resume() const noexcept
+        {
+        }
+    };
+    return YieldPostAwaiter{*this};
+}
+
+/**
+ * Schedule coroutine resumption as a job on the JobQueue.
+ * A shared_ptr capture (sp) prevents this CoroTaskRunner from being
+ * destroyed while the job is queued but not yet executed.
+ *
+ * @return false if the JobQueue rejected the job (shutting down)
+ */
+inline bool
+JobQueue::CoroTaskRunner::post()
+{
+    {
+        std::lock_guard lk(mutex_run_);
+        ++runCount_;
+    }
+
+    // sp prevents 'this' from being destroyed while the job is pending
+    if (jq_.addJob(type_, name_, [this, sp = shared_from_this()]() { resume(); }))
+    {
+        return true;
+    }
+
+    // The coroutine will not run. Undo the runCount_ increment.
+    std::lock_guard lk(mutex_run_);
+    --runCount_;
+    cv_.notify_all();
+    return false;
+}
+
+/**
+ * Resume the coroutine on the current thread.
+ *
+ * Steps:
+ *   1. Decrement nSuspend_ (under jq_.m_mutex)
+ *   2. Swap in this coroutine's LocalValues for thread-local isolation
+ *   3. Resume the coroutine handle (under mutex_)
+ *   4. Swap out LocalValues, restoring the thread's previous state
+ *   5. Decrement runCount_ and notify join() waiters
+ *
+ * @pre post() must have been called before resume(). Direct calls
+ *      without a prior post() will corrupt runCount_ and break join().
+ * Note: runCount_ is NOT incremented here — post() already did that.
+ * This ensures join() stays blocked for the entire post->resume lifetime.
+ */
+inline void
+JobQueue::CoroTaskRunner::resume()
+{
+    {
+        std::lock_guard lock(jq_.m_mutex);
+        --jq_.nSuspend_;
+    }
+    auto saved = detail::getLocalValues().release();
+    detail::getLocalValues().reset(&lvs_);
+    std::lock_guard lock(mutex_);
+    XRPL_ASSERT(
+        task_.handle() && !task_.done(),
+        "xrpl::JobQueue::CoroTaskRunner::resume : task handle is valid and not done");
+    task_.handle().resume();
+    detail::getLocalValues().release();
+    detail::getLocalValues().reset(saved);
+    if (task_.done())
+    {
+        finished_ = true;
+        // Break the shared_ptr cycle: frame -> shared_ptr<runner> -> this.
+        // Use std::move (not task_ = {}) so task_.handle_ is null BEFORE the
+        // frame is destroyed. operator= would destroy the frame while handle_
+        // still holds the old value -- a re-entrancy hazard on GCC-12 if
+        // frame destruction triggers runner cleanup.
+        [[maybe_unused]] auto completed = std::move(task_);
+    }
+    std::lock_guard lk(mutex_run_);
+    --runCount_;
+    cv_.notify_all();
+}
+
+/**
+ * @return true if the coroutine has not yet run to completion
+ */
+inline bool
+JobQueue::CoroTaskRunner::runnable() const
+{
+    // After normal completion, task_ is reset to break the shared_ptr cycle
+    // (handle_ becomes null). A null handle means the coroutine is done.
+    return task_.handle() && !task_.done();
+}
+
+/**
+ * Handle early termination when the coroutine never ran (e.g. JobQueue
+ * is stopping). Decrements nSuspend_ and destroys the coroutine frame
+ * to break the shared_ptr cycle: frame -> lambda -> runner -> frame.
+ */
+inline void
+JobQueue::CoroTaskRunner::expectEarlyExit()
+{
+    if (!finished_)
+    {
+        std::lock_guard lock(jq_.m_mutex);
+        --jq_.nSuspend_;
+        finished_ = true;
+    }
+    // Break the shared_ptr cycle: frame -> shared_ptr<runner> -> this.
+    // The coroutine is at initial_suspend and never ran user code, so
+    // destroying it is safe. Use std::move (not task_ = {}) so
+    // task_.handle_ is null before the frame is destroyed.
+    {
+        [[maybe_unused]] auto completed = std::move(task_);
+    }
+    storedFunc_.reset();
+}
+
+/**
+ * Block until all pending/active resume operations complete.
+ * Uses cv_ + mutex_run_ to wait until runCount_ reaches 0 or
+ * finished_ becomes true. The finished_ check handles the case
+ * where resume() is called directly (without post()), which
+ * decrements runCount_ below zero. In that scenario runCount_
+ * never returns to 0, but finished_ becoming true guarantees
+ * the coroutine is done and no more resumes will occur.
+ */
+inline void
+JobQueue::CoroTaskRunner::join()
+{
+    std::unique_lock<std::mutex> lk(mutex_run_);
+    cv_.wait(lk, [this]() { return runCount_ == 0 || finished_; });
+}
+
+}  // namespace xrpl

include/xrpl/core/JobQueue.h

@@ -2,6 +2,7 @@
 
 #include <xrpl/basics/LocalValue.h>
 #include <xrpl/core/ClosureCounter.h>
+#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/JobTypeData.h>
 #include <xrpl/core/JobTypes.h>
 #include <xrpl/core/detail/Workers.h>
@@ -9,6 +10,7 @@
 
 #include <boost/coroutine/all.hpp>
 
+#include <coroutine>
 #include <set>
 
 namespace xrpl {
@@ -119,6 +121,419 @@ public:
         join();
     };
 
+    /** C++20 coroutine lifecycle manager. Replaces Coro for new code.
+     *
+     *  Class / Inheritance / Dependency Diagram
+     *  =========================================
+     *
+     *  std::enable_shared_from_this<CoroTaskRunner>
+     *            ^
+     *            | (public inheritance)
+     *            |
+     *  CoroTaskRunner
+     *  +---------------------------------------------------+
+     *  | - lvs_         : detail::LocalValues               |
+     *  | - jq_          : JobQueue&                         |
+     *  | - type_        : JobType                           |
+     *  | - name_        : std::string                       |
+     *  | - runCount_    : int         (in-flight resumes)    |
+     *  | - mutex_       : std::mutex      (coroutine guard) |
+     *  | - mutex_run_   : std::mutex      (join guard)      |
+     *  | - cv_          : condition_variable                 |
+     *  | - task_        : CoroTask<void>                    |
+     *  | - storedFunc_  : unique_ptr<FuncBase> (type-erased)|
+     *  +---------------------------------------------------+
+     *  | + init(F&&)         : set up coroutine callable    |
+     *  | + onSuspend()       : ++jq_.nSuspend_              |
+     *  | + onUndoSuspend()   : --jq_.nSuspend_              |
+     *  | + suspend()         : returns SuspendAwaiter       |
+     *  | + post()            : schedule resume on JobQueue  |
+     *  | + resume()          : resume coroutine on caller   |
+     *  | + runnable()        : !task_.done()                |
+     *  | + expectEarlyExit() : teardown for failed post     |
+     *  | + join()            : block until not running       |
+     *  +---------------------------------------------------+
+     *          |                          |
+     *          | owns                     | references
+     *          v                          v
+     *    CoroTask<void>             JobQueue
+     *    (coroutine frame)          (thread pool + nSuspend_)
+     *
+     *    FuncBase / FuncStore<F>    (type-erased heap storage
+     *                                for the coroutine lambda)
+     *
+     *  Coroutine Lifecycle (Control Flow)
+     *  ===================================
+     *
+     *  Caller thread              JobQueue worker thread
+     *  -------------              ----------------------
+     *  postCoroTask(f)
+     *    |
+     *    +-- check stopping_ (reject if JQ shutting down)
+     *    +-- ++nSuspend_  (lazy start counts as suspended)
+     *    +-- make_shared<CoroTaskRunner>
+     *    +-- init(f)
+     *    |     +-- store lambda on heap (FuncStore)
+     *    |     +-- task_ = f(shared_from_this())
+     *    |           [coroutine created, suspended at initial_suspend]
+     *    +-- post()
+     *    |     +-- ++runCount_
+     *    |     +-- addJob(type_, [resume]{})
+     *    |                                    resume()
+     *    |                                      |
+     *    |                                      +-- --nSuspend_
+     *    |                                      +-- swap in LocalValues
+     *    |                                      +-- task_.handle().resume()
+     *    |                                      |     [coroutine body runs]
+     *    |                                      |     ...
+     *    |                                      |     co_await suspend()
+     *    |                                      |       +-- ++nSuspend_
+     *    |                                      |       [coroutine suspends]
+     *    |                                      +-- swap out LocalValues
+     *    |                                      +-- --runCount_
+     *    |                                      +-- cv_.notify_all()
+     *    |
+     *  post()  <-- called externally or by yieldAndPost()
+     *    +-- ++runCount_
+     *    +-- addJob(type_, [resume]{})
+     *                                         resume()
+     *                                           |
+     *                                           +-- [coroutine body continues]
+     *                                           +-- co_return
+     *                                           +-- --runCount_
+     *                                           +-- cv_.notify_all()
+     *  join()
+     *    +-- cv_.wait([]{runCount_ == 0})
+     *    +-- [done]
+     *
+     *  Usage Examples
+     *  ==============
+     *
+     *  1. Fire-and-forget coroutine (most common pattern):
+     *
+     *      jq.postCoroTask(jtCLIENT, "MyWork",
+     *          [](auto runner) -> CoroTask<void> {
+     *              doSomeWork();
+     *              co_await runner->suspend();  // yield to other jobs
+     *              doMoreWork();
+     *              co_return;
+     *          });
+     *
+     *  2. Manually controlling suspend / resume (external trigger):
+     *
+     *      auto runner = jq.postCoroTask(jtCLIENT, "ExtTrigger",
+     *          [&result](auto runner) -> CoroTask<void> {
+     *              startAsyncOperation(callback);
+     *              co_await runner->suspend();
+     *              // callback called runner->post() to get here
+     *              result = collectResult();
+     *              co_return;
+     *          });
+     *      // ... later, from the callback:
+     *      runner->post();   // reschedule the coroutine on the JobQueue
+     *
+     *  3. Using yieldAndPost() for automatic suspend + repost:
+     *
+     *      jq.postCoroTask(jtCLIENT, "AutoRepost",
+     *          [](auto runner) -> CoroTask<void> {
+     *              step1();
+     *              co_await runner->yieldAndPost();  // yield + auto-repost
+     *              step2();
+     *              co_await runner->yieldAndPost();
+     *              step3();
+     *              co_return;
+     *          });
+     *
+     *  4. Checking shutdown after co_await (cooperative cancellation):
+     *
+     *      jq.postCoroTask(jtCLIENT, "Cancellable",
+     *          [&jq](auto runner) -> CoroTask<void> {
+     *              while (moreWork()) {
+     *                  co_await runner->yieldAndPost();
+     *                  if (jq.isStopping())
+     *                      co_return;  // bail out cleanly
+     *                  processNextItem();
+     *              }
+     *              co_return;
+     *          });
+     *
+     *  Caveats / Pitfalls
+     *  ==================
+     *
+     *  BUG-RISK: Calling suspend() without a matching post()/resume().
+     *    After co_await runner->suspend(), the coroutine is parked and
+     *    nSuspend_ is incremented.  If nothing ever calls post() or
+     *    resume(), the coroutine is leaked and JobQueue::stop() will
+     *    hang forever waiting for nSuspend_ to reach zero.
+     *
+     *  BUG-RISK: Calling post() on an already-running coroutine.
+     *    post() schedules a resume() job.  If the coroutine has not
+     *    actually suspended yet (no co_await executed), the resume job
+     *    will try to call handle().resume() while the coroutine is still
+     *    running on another thread.  This is UB.  The mutex_ prevents
+     *    data corruption but the logic is wrong — always co_await
+     *    suspend() before calling post().  (The test incorrect_order()
+     *    shows this works only because mutex_ serializes the calls.)
+     *
+     *  BUG-RISK: Dropping the shared_ptr<CoroTaskRunner> before join().
+     *    The CoroTaskRunner destructor asserts that finished_ is true
+     *    (the coroutine completed). If you let the last shared_ptr die
+     *    while the coroutine is still running or suspended, you get an
+     *    assertion failure in debug and UB in release.  Always call
+     *    join() or expectEarlyExit() first.
+     *
+     *  BUG-RISK: Lambda captures outliving the coroutine frame.
+     *    The lambda passed to postCoroTask is heap-allocated (FuncStore)
+     *    to prevent dangling.  But objects captured by pointer still need
+     *    their own lifetime management.  If you capture a raw pointer to
+     *    a stack variable, and the stack frame exits before the coroutine
+     *    finishes, the pointer dangles.  Use shared_ptr or ensure the
+     *    pointed-to object outlives the coroutine.
+     *
+     *  BUG-RISK: Forgetting co_return in a void coroutine.
+     *    If the coroutine body falls off the end without co_return,
+     *    the compiler may silently treat it as co_return (per standard),
+     *    but some compilers warn.  Always write explicit co_return.
+     *
+     *  LIMITATION: CoroTaskRunner only supports CoroTask<void>.
+     *    The task_ member is CoroTask<void>.  To return values from
+     *    the top-level coroutine, write through a captured pointer
+     *    (as the tests demonstrate), or co_await inner CoroTask<T>
+     *    coroutines that return values.
+     *
+     *  LIMITATION: One coroutine per CoroTaskRunner.
+     *    init() must be called exactly once.  You cannot reuse a
+     *    CoroTaskRunner to run a second coroutine.  Create a new one
+     *    via postCoroTask() instead.
+     *
+     *  LIMITATION: No timeout on join().
+     *    join() blocks indefinitely.  If the coroutine is suspended
+     *    and never posted, join() will deadlock.  Use timed waits
+     *    on the gate pattern (condition_variable + wait_for) in tests.
+     */
+    class CoroTaskRunner : public std::enable_shared_from_this<CoroTaskRunner>
+    {
+    private:
+        // Per-coroutine thread-local storage. Swapped in before resume()
+        // and swapped out after, so each coroutine sees its own LocalValue
+        // state regardless of which worker thread executes it.
+        detail::LocalValues lvs_;
+
+        // Back-reference to the owning JobQueue. Used to post jobs,
+        // increment/decrement nSuspend_, and acquire jq_.m_mutex.
+        JobQueue& jq_;
+
+        // Job type passed to addJob() when posting this coroutine.
+        JobType type_;
+
+        // Human-readable name for this coroutine job (for logging).
+        std::string name_;
+
+        // Number of in-flight resume operations (pending + active).
+        // Incremented by post(), decremented when resume() finishes.
+        // Guarded by mutex_run_. join() blocks until this reaches 0.
+        //
+        // A counter (not a bool) is needed because post() can be called
+        // from within the coroutine body (e.g. via yieldAndPost()),
+        // enqueuing a second resume while the first is still running.
+        // A bool would be clobbered: R2.post() sets true, then R1's
+        // cleanup sets false — losing the fact that R2 is still pending.
+        int runCount_;
+
+        // Serializes all coroutine resume() calls, preventing concurrent
+        // execution of the coroutine body on multiple threads. Handles the
+        // race where post() enqueues a resume before the coroutine has
+        // actually suspended (post-before-suspend pattern).
+        std::mutex mutex_;
+
+        // Guards runCount_. Used with cv_ for join() to wait
+        // until all pending/active resume operations complete.
+        std::mutex mutex_run_;
+
+        // Notified when runCount_ reaches zero, allowing
+        // join() waiters to wake up.
+        std::condition_variable cv_;
+
+        // The coroutine handle wrapper. Owns the coroutine frame.
+        // Set by init(). Reset to empty in resume() upon coroutine
+        // completion (to break the shared_ptr cycle) or in
+        // expectEarlyExit() on early termination.
+        CoroTask<void> task_;
+
+        /**
+         * Type-erased base for heap-stored callables.
+         * Prevents the coroutine lambda from being destroyed before
+         * the coroutine frame is done with it.
+         *
+         * @see FuncStore
+         */
+        struct FuncBase
+        {
+            virtual ~FuncBase() = default;
+        };
+
+        /**
+         * Concrete type-erased storage for a callable of type F.
+         * The coroutine frame stores a reference to the lambda's implicit
+         * object parameter. If the lambda is a temporary, that reference
+         * dangles after the call returns. FuncStore keeps it alive on
+         * the heap for the lifetime of the CoroTaskRunner.
+         */
+        template <class F>
+        struct FuncStore : FuncBase
+        {
+            F func;  // The stored callable (coroutine lambda).
+            explicit FuncStore(F&& f) : func(std::move(f))
+            {
+            }
+        };
+
+        // Heap-allocated callable storage. Set by init(), ensures the
+        // lambda outlives the coroutine frame that references it.
+        std::unique_ptr<FuncBase> storedFunc_;
+
+        // True once the coroutine has completed or expectEarlyExit() was
+        // called. Asserted in the destructor (debug) to catch leaked
+        // runners. Available in all builds to guard expectEarlyExit()
+        // against double-decrementing nSuspend_.
+        bool finished_ = false;
+
+    public:
+        /**
+         * Tag type for private construction. Prevents external code
+         * from constructing CoroTaskRunner directly. Use postCoroTask().
+         */
+        struct create_t
+        {
+            explicit create_t() = default;
+        };
+
+        /**
+         * Construct a CoroTaskRunner. Private by convention (create_t tag).
+         *
+         * @param jq   The JobQueue this coroutine will run on
+         * @param type Job type for scheduling priority
+         * @param name Human-readable name for logging
+         */
+        CoroTaskRunner(create_t, JobQueue&, JobType, std::string const&);
+
+        CoroTaskRunner(CoroTaskRunner const&) = delete;
+        CoroTaskRunner&
+        operator=(CoroTaskRunner const&) = delete;
+
+        /**
+         * Destructor. Asserts (debug) that the coroutine has finished
+         * or expectEarlyExit() was called.
+         */
+        ~CoroTaskRunner();
+
+        /**
+         * Initialize with a coroutine-returning callable.
+         * Must be called exactly once, after the object is managed by
+         * shared_ptr (because init uses shared_from_this internally).
+         * This is handled automatically by postCoroTask().
+         *
+         * @param f Callable: CoroTask<void>(shared_ptr<CoroTaskRunner>)
+         */
+        template <class F>
+        void
+        init(F&& f);
+
+        /**
+         * Increment the JobQueue's suspended-coroutine count (nSuspend_).
+         * Called when the coroutine is about to suspend. Every call
+         * must be balanced by a corresponding decrement (via resume()
+         * or onUndoSuspend()), or JobQueue::stop() will hang.
+         */
+        void
+        onSuspend();
+
+        /**
+         * Decrement nSuspend_ without resuming.
+         * Used to undo onSuspend() when a scheduled post() fails
+         * (e.g. JobQueue is stopping).
+         */
+        void
+        onUndoSuspend();
+
+        /**
+         * Suspend the coroutine.
+         * The awaiter's await_suspend() increments nSuspend_ before the
+         * coroutine actually suspends. The caller must later call post()
+         * or resume() to continue execution.
+         *
+         * @return An awaiter for use with `co_await runner->suspend()`
+         */
+        auto
+        suspend();
+
+        /**
+         * Suspend the coroutine and immediately repost it on the
+         * JobQueue. Combines suspend() + post() atomically inside
+         * await_suspend, so there is no window where an external
+         * event could race between the two.
+         *
+         * Equivalent to JobQueueAwaiter but defined as an inline
+         * awaiter returned from a member function. This avoids a
+         * GCC-12 coroutine codegen bug where an external awaiter
+         * struct (JobQueueAwaiter) used at multiple co_await points
+         * corrupts the coroutine state machine's resume index,
+         * causing the coroutine to hang on the third resumption.
+         *
+         * @return An awaiter for use with `co_await runner->yieldAndPost()`
+         */
+        auto
+        yieldAndPost();
+
+        /**
+         * Schedule coroutine resumption as a job on the JobQueue.
+         * Captures shared_from_this() to prevent this runner from being
+         * destroyed while the job is queued.
+         *
+         * @return true if the job was accepted; false if the JobQueue
+         *         is stopping (caller must handle cleanup)
+         */
+        bool
+        post();
+
+        /**
+         * Resume the coroutine on the current thread.
+         * Decrements nSuspend_, swaps in LocalValues, resumes the
+         * coroutine handle, swaps out LocalValues, and notifies join()
+         * waiters. Lock ordering (sequential, non-overlapping):
+         * jq_.m_mutex -> mutex_ -> mutex_run_.
+         *
+         * @pre post() must have been called before resume(). Direct
+         *      calls without a prior post() will corrupt runCount_
+         *      and break join().
+         */
+        void
+        resume();
+
+        /**
+         * @return true if the coroutine has not yet run to completion
+         */
+        bool
+        runnable() const;
+
+        /**
+         * Handle early termination when the coroutine never ran.
+         * Decrements nSuspend_ and destroys the coroutine frame to
+         * break the shared_ptr cycle (frame -> lambda -> runner -> frame).
+         * Called by postCoroTask() when post() fails.
+         */
+        void
+        expectEarlyExit();
+
+        /**
+         * Block until all pending/active resume operations complete.
+         * Uses cv_ + mutex_run_ to wait until runCount_ reaches 0.
+         * Warning: deadlocks if the coroutine is suspended and never posted.
+         */
+        void
+        join();
+    };
+
     using JobFunction = std::function<void()>;
 
     JobQueue(
@@ -165,6 +580,19 @@ public:
     std::shared_ptr<Coro>
     postCoro(JobType t, std::string const& name, F&& f);
 
+    /** Creates a C++20 coroutine and adds a job to the queue to run it.
+
+        @param t The type of job.
+        @param name Name of the job.
+        @param f Callable with signature
+            CoroTask<void>(std::shared_ptr<CoroTaskRunner>).
+
+        @return shared_ptr to posted CoroTaskRunner. nullptr if not successful.
+    */
+    template <class F>
+    std::shared_ptr<CoroTaskRunner>
+    postCoroTask(JobType t, std::string const& name, F&& f);
+
     /** Jobs waiting at this priority.
      */
     int
@@ -379,6 +807,7 @@ private:
 }  // namespace xrpl
 
 #include <xrpl/core/Coro.ipp>
+#include <xrpl/core/CoroTaskRunner.ipp>
 
 namespace xrpl {
 
@@ -401,4 +830,69 @@ JobQueue::postCoro(JobType t, std::string const& name, F&& f)
     return coro;
 }
 
+// postCoroTask — entry point for launching a C++20 coroutine on the JobQueue.
+//
+// Control Flow
+// ============
+//
+//   postCoroTask(t, name, f)
+//     |
+//     +-- 1. Check stopping_ — reject if JQ shutting down
+//     |
+//     +-- 2. ++nSuspend_   (mirrors Boost Coro ctor's implicit yield)
+//     |        The coroutine is "suspended" from the JobQueue's perspective
+//     |        even though it hasn't run yet — this keeps the JQ shutdown
+//     |        logic correct (it waits for nSuspend_ to reach 0).
+//     |
+//     +-- 3. Create CoroTaskRunner (shared_ptr, ref-counted)
+//     |
+//     +-- 4. runner->init(f)
+//     |        +-- Heap-allocate the lambda (FuncStore) to prevent
+//     |        |   dangling captures in the coroutine frame
+//     |        +-- task_ = f(shared_from_this())
+//     |              [coroutine created but NOT started — lazy initial_suspend]
+//     |
+//     +-- 5. runner->post()
+//     |        +-- addJob(type_, [resume]{})   → resume on worker thread
+//     |        +-- failure (JQ stopping):
+//     |              +-- runner->expectEarlyExit()
+//     |              |     --nSuspend_, destroy coroutine frame
+//     |              +-- return nullptr
+//
+// Why async post() instead of synchronous resume()?
+// ==================================================
+// The initial dispatch MUST use async post() so the coroutine body runs on
+// a JobQueue worker thread, not the caller's thread.  resume() swaps the
+// caller's thread-local LocalValues with the coroutine's private copy.
+// If the coroutine mutates LocalValues (e.g. thread_specific_storage test),
+// those mutations bleed back into the caller's thread-local state after the
+// swap-out, corrupting subsequent tests that share the same thread pool.
+// Async post() avoids this by running the coroutine on a worker thread whose
+// LocalValues are managed by the thread pool, not by the caller.
+//
+template <class F>
+std::shared_ptr<JobQueue::CoroTaskRunner>
+JobQueue::postCoroTask(JobType t, std::string const& name, F&& f)
+{
+    // Reject if the JQ is shutting down — matches addJob()'s stopping_ check.
+    // Must check before incrementing nSuspend_ to avoid leaving an orphan
+    // count that would cause stop() to hang.
+    if (stopping_)
+        return nullptr;
+
+    {
+        std::lock_guard lock(m_mutex);
+        ++nSuspend_;
+    }
+
+    auto runner = std::make_shared<CoroTaskRunner>(CoroTaskRunner::create_t{}, *this, t, name);
+    runner->init(std::forward<F>(f));
+    if (!runner->post())
+    {
+        runner->expectEarlyExit();
+        runner.reset();
+    }
+    return runner;
+}
+
 }  // namespace xrpl

include/xrpl/core/JobQueueAwaiter.h

@@ -0,0 +1,206 @@
+#pragma once
+
+#include <xrpl/core/JobQueue.h>
+
+#include <coroutine>
+#include <memory>
+
+namespace xrpl {
+
+/**
+ * Awaiter that suspends and immediately reschedules on the JobQueue.
+ * Equivalent to calling yield() followed by post() in the old Coro API.
+ *
+ * Usage:
+ *     co_await JobQueueAwaiter{runner};
+ *
+ * What it waits for: The coroutine is re-queued as a job and resumes
+ * when a worker thread picks it up.
+ *
+ * Which thread resumes: A JobQueue worker thread.
+ *
+ * What await_resume() returns: void.
+ *
+ * Dependency Diagram
+ * ==================
+ *
+ *   JobQueueAwaiter
+ *   +----------------------------------------------+
+ *   | + runner : shared_ptr<CoroTaskRunner>         |
+ *   +----------------------------------------------+
+ *   | + await_ready()   -> false (always suspend)   |
+ *   | + await_suspend() -> bool (suspend or cancel) |
+ *   | + await_resume()  -> void                     |
+ *   +----------------------------------------------+
+ *          |                         |
+ *          | uses                    | uses
+ *          v                         v
+ *   CoroTaskRunner              JobQueue
+ *   .onSuspend()                (via runner->post() -> addJob)
+ *   .onUndoSuspend()
+ *   .post()
+ *
+ * Control Flow (await_suspend)
+ * ============================
+ *
+ *   co_await JobQueueAwaiter{runner}
+ *     |
+ *     +-- await_ready() -> false
+ *     +-- await_suspend(handle)
+ *           |
+ *           +-- runner->onSuspend()     // ++nSuspend_
+ *           +-- runner->post()          // addJob to JobQueue
+ *           |     |
+ *           |     +-- success? return noop_coroutine()
+ *           |     |     // coroutine stays suspended;
+ *           |     |     // worker thread will call resume()
+ *           |     +-- failure? (JQ stopping)
+ *           |           +-- runner->onUndoSuspend()  // --nSuspend_
+ *           |           +-- return handle  // symmetric transfer back
+ *           |                              // coroutine continues immediately
+ *           |                              // so it can clean up and co_return
+ *
+ * DEPRECATED — prefer `co_await runner->yieldAndPost()`
+ * =====================================================
+ *
+ * GCC-12 has a coroutine codegen bug where using this external awaiter
+ * struct at multiple co_await points in the same coroutine corrupts the
+ * state machine's resume index. After the second co_await, the third
+ * resumption enters handle().resume() but never reaches await_resume()
+ * or any subsequent user code — the coroutine hangs indefinitely.
+ *
+ * The fix is `co_await runner->yieldAndPost()`, which defines the
+ * awaiter as an inline struct inside a CoroTaskRunner member function.
+ * GCC-12 handles inline awaiters correctly at multiple co_await points.
+ *
+ * This struct is retained for single-use scenarios and documentation
+ * purposes. For any code that may use co_await in a loop or at
+ * multiple points, always use `runner->yieldAndPost()`.
+ *
+ * Usage Examples
+ * ==============
+ *
+ * 1. Yield and auto-repost (preferred — works on all compilers):
+ *
+ *     CoroTask<void> handler(auto runner) {
+ *         doPartA();
+ *         co_await runner->yieldAndPost();   // yield + repost
+ *         doPartB();                         // runs on a worker thread
+ *         co_return;
+ *     }
+ *
+ * 2. Multiple yield points in a loop:
+ *
+ *     CoroTask<void> batchProcessor(auto runner) {
+ *         for (auto& item : items) {
+ *             process(item);
+ *             co_await runner->yieldAndPost();  // let other jobs run
+ *         }
+ *         co_return;
+ *     }
+ *
+ * 3. Graceful shutdown — checking after resume:
+ *
+ *     CoroTask<void> longTask(auto runner, JobQueue& jq) {
+ *         while (hasWork()) {
+ *             co_await runner->yieldAndPost();
+ *             // If JQ is stopping, await_suspend resumes the coroutine
+ *             // immediately without re-queuing. Always check
+ *             // isStopping() to decide whether to proceed:
+ *             if (jq.isStopping())
+ *                 co_return;
+ *             doNextChunk();
+ *         }
+ *         co_return;
+ *     }
+ *
+ * Caveats / Pitfalls
+ * ==================
+ *
+ * BUG-RISK: Using a stale or null runner.
+ *   The runner shared_ptr must be valid and point to the CoroTaskRunner
+ *   that owns the coroutine currently executing. Passing a runner from
+ *   a different coroutine, or a default-constructed shared_ptr, is UB.
+ *
+ * BUG-RISK: Assuming resume happens on the same thread.
+ *   After co_await, the coroutine resumes on whatever worker thread
+ *   picks up the job. Do not rely on thread-local state unless it is
+ *   managed through LocalValue (which CoroTaskRunner automatically
+ *   swaps in/out).
+ *
+ * BUG-RISK: Ignoring the shutdown path.
+ *   When the JobQueue is stopping, post() fails and await_suspend()
+ *   resumes the coroutine immediately (symmetric transfer back to h).
+ *   The coroutine body continues on the same thread. If your code
+ *   after co_await assumes it was re-queued and is running on a worker
+ *   thread, that assumption breaks during shutdown. Always handle the
+ *   "JQ is stopping" case, either by checking jq.isStopping() or by
+ *   letting the coroutine fall through to co_return naturally.
+ *
+ * DIFFERENCE from runner->suspend() + runner->post():
+ *   Both JobQueueAwaiter and yieldAndPost() combine suspend + post
+ *   in one atomic operation. With the manual suspend()/post() pattern,
+ *   there is a window between the two calls where an external event
+ *   could race. The atomic awaiters remove that window — onSuspend()
+ *   and post() happen within the same await_suspend() call while the
+ *   coroutine is guaranteed to be suspended. Use yieldAndPost() unless
+ *   you need an external party to decide *when* to call post().
+ */
+struct JobQueueAwaiter
+{
+    // The CoroTaskRunner that owns the currently executing coroutine.
+    std::shared_ptr<JobQueue::CoroTaskRunner> runner;
+
+    /**
+     * Always returns false so the coroutine suspends.
+     */
+    bool
+    await_ready() const noexcept
+    {
+        return false;
+    }
+
+    /**
+     * Increment nSuspend (equivalent to yield()) and schedule resume
+     * on the JobQueue (equivalent to post()). If the JobQueue is
+     * stopping, undoes the suspend count and transfers back to the
+     * coroutine so it can clean up and co_return.
+     *
+     * Returns a coroutine_handle<> (symmetric transfer) instead of
+     * bool to work around a GCC-12 codegen bug where bool-returning
+     * await_suspend leaves the coroutine in an invalid state —
+     * neither properly suspended nor resumed — causing a hang.
+     *
+     * WARNING: GCC-12 has an additional codegen bug where using this
+     * external awaiter struct at multiple co_await points in the same
+     * coroutine corrupts the state machine's resume index, causing the
+     * coroutine to hang on the third resumption. Prefer
+     * `co_await runner->yieldAndPost()` which uses an inline awaiter
+     * that GCC-12 handles correctly.
+     *
+     * @return noop_coroutine() to stay suspended (job posted);
+     *         the caller's handle to resume immediately (JQ stopping)
+     */
+    std::coroutine_handle<>
+    await_suspend(std::coroutine_handle<> h)
+    {
+        XRPL_ASSERT(runner, "xrpl::JobQueueAwaiter::await_suspend : runner is valid");
+        runner->onSuspend();
+        if (!runner->post())
+        {
+            // JobQueue is stopping. Undo the suspend count and
+            // transfer back to the coroutine so it can clean up
+            // and co_return.
+            runner->onUndoSuspend();
+            return h;
+        }
+        return std::noop_coroutine();
+    }
+
+    void
+    await_resume() const noexcept
+    {
+    }
+};
+
+}  // namespace xrpl

include/xrpl/protocol/detail/transactions.macro

@@ -42,7 +42,7 @@ TRANSACTION(ttPAYMENT, 0, Payment,
 
 /** This transaction type creates an escrow object. */
 #if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/escrow/EscrowCreate.h>
+#   include <xrpl/tx/transactors/escrow/Escrow.h>
 #endif
 TRANSACTION(ttESCROW_CREATE, 1, EscrowCreate,
     Delegation::delegable,
@@ -58,9 +58,6 @@ TRANSACTION(ttESCROW_CREATE, 1, EscrowCreate,
 }))
 
 /** This transaction type completes an existing escrow. */
-#if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/escrow/EscrowFinish.h>
-#endif
 TRANSACTION(ttESCROW_FINISH, 2, EscrowFinish,
     Delegation::delegable,
     uint256{},
@@ -97,7 +94,7 @@ TRANSACTION(ttACCOUNT_SET, 3, AccountSet,
 
 /** This transaction type cancels an existing escrow. */
 #if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/escrow/EscrowCancel.h>
+#   include <xrpl/tx/transactors/escrow/Escrow.h>
 #endif
 TRANSACTION(ttESCROW_CANCEL, 4, EscrowCancel,
     Delegation::delegable,
@@ -183,7 +180,7 @@ TRANSACTION(ttSIGNER_LIST_SET, 12, SignerListSet,
 
 /** This transaction type creates a new unidirectional XRP payment channel. */
 #if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/payment_channel/PayChanCreate.h>
+#   include <xrpl/tx/transactors/payment_channel/PayChan.h>
 #endif
 TRANSACTION(ttPAYCHAN_CREATE, 13, PaymentChannelCreate,
     Delegation::delegable,
@@ -199,9 +196,6 @@ TRANSACTION(ttPAYCHAN_CREATE, 13, PaymentChannelCreate,
 }))
 
 /** This transaction type funds an existing unidirectional XRP payment channel. */
-#if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/payment_channel/PayChanFund.h>
-#endif
 TRANSACTION(ttPAYCHAN_FUND, 14, PaymentChannelFund,
     Delegation::delegable,
     uint256{},
@@ -213,9 +207,6 @@ TRANSACTION(ttPAYCHAN_FUND, 14, PaymentChannelFund,
 }))
 
 /** This transaction type submits a claim against an existing unidirectional payment channel. */
-#if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/payment_channel/PayChanClaim.h>
-#endif
 TRANSACTION(ttPAYCHAN_CLAIM, 15, PaymentChannelClaim,
     Delegation::delegable,
     uint256{},
@@ -626,7 +617,7 @@ TRANSACTION(ttXCHAIN_CREATE_BRIDGE, 48, XChainCreateBridge,
 
 /** This transaction type creates or updates a DID */
 #if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/did/DIDSet.h>
+#   include <xrpl/tx/transactors/did/DID.h>
 #endif
 TRANSACTION(ttDID_SET, 49, DIDSet,
     Delegation::delegable,
@@ -639,9 +630,6 @@ TRANSACTION(ttDID_SET, 49, DIDSet,
 }))
 
 /** This transaction type deletes a DID */
-#if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/did/DIDDelete.h>
-#endif
 TRANSACTION(ttDID_DELETE, 50, DIDDelete,
     Delegation::delegable,
     featureDID,
@@ -751,7 +739,7 @@ TRANSACTION(ttMPTOKEN_AUTHORIZE, 57, MPTokenAuthorize,
 
 /** This transaction type create an Credential instance */
 #if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/credentials/CredentialCreate.h>
+#   include <xrpl/tx/transactors/credentials/Credentials.h>
 #endif
 TRANSACTION(ttCREDENTIAL_CREATE, 58, CredentialCreate,
     Delegation::delegable,
@@ -765,9 +753,6 @@ TRANSACTION(ttCREDENTIAL_CREATE, 58, CredentialCreate,
 }))
 
 /** This transaction type accept an Credential object */
-#if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/credentials/CredentialAccept.h>
-#endif
 TRANSACTION(ttCREDENTIAL_ACCEPT, 59, CredentialAccept,
     Delegation::delegable,
     featureCredentials,
@@ -778,9 +763,6 @@ TRANSACTION(ttCREDENTIAL_ACCEPT, 59, CredentialAccept,
 }))
 
 /** This transaction type delete an Credential object */
-#if TRANSACTION_INCLUDE
-#   include <xrpl/tx/transactors/credentials/CredentialDelete.h>
-#endif
 TRANSACTION(ttCREDENTIAL_DELETE, 60, CredentialDelete,
     Delegation::delegable,
     featureCredentials,

include/xrpl/tx/transactors/credentials/CredentialAccept.h

@@ -1,29 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class CredentialAccept : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit CredentialAccept(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static std::uint32_t
-    getFlagsMask(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/credentials/CredentialCreate.h

@@ -1,29 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class CredentialCreate : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit CredentialCreate(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static std::uint32_t
-    getFlagsMask(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/credentials/CredentialDelete.h

@@ -1,29 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class CredentialDelete : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit CredentialDelete(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static std::uint32_t
-    getFlagsMask(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/credentials/Credentials.h

@@ -0,0 +1,77 @@
+#pragma once
+
+#include <xrpl/tx/Transactor.h>
+
+namespace xrpl {
+
+class CredentialCreate : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit CredentialCreate(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static std::uint32_t
+    getFlagsMask(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+//------------------------------------------------------------------------------
+
+class CredentialDelete : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit CredentialDelete(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static std::uint32_t
+    getFlagsMask(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+//------------------------------------------------------------------------------
+
+class CredentialAccept : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit CredentialAccept(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static std::uint32_t
+    getFlagsMask(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+}  // namespace xrpl

include/xrpl/tx/transactors/did/DID.h

@@ -4,6 +4,24 @@
 
 namespace xrpl {
 
+class DIDSet : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit DIDSet(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+//------------------------------------------------------------------------------
+
 class DIDDelete : public Transactor
 {
 public:

include/xrpl/tx/transactors/did/DIDSet.h

@@ -1,23 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class DIDSet : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit DIDSet(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/escrow/Escrow.h

@@ -0,0 +1,80 @@
+#pragma once
+
+#include <xrpl/tx/Transactor.h>
+
+namespace xrpl {
+
+class EscrowCreate : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Custom};
+
+    explicit EscrowCreate(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static TxConsequences
+    makeTxConsequences(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+//------------------------------------------------------------------------------
+
+class EscrowFinish : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit EscrowFinish(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static bool
+    checkExtraFeatures(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static NotTEC
+    preflightSigValidated(PreflightContext const& ctx);
+
+    static XRPAmount
+    calculateBaseFee(ReadView const& view, STTx const& tx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+//------------------------------------------------------------------------------
+
+class EscrowCancel : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit EscrowCancel(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+}  // namespace xrpl

include/xrpl/tx/transactors/escrow/EscrowCancel.h

@@ -1,26 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class EscrowCancel : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit EscrowCancel(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/escrow/EscrowCreate.h

@@ -1,29 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class EscrowCreate : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Custom};
-
-    explicit EscrowCreate(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static TxConsequences
-    makeTxConsequences(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/escrow/EscrowFinish.h

@@ -1,35 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class EscrowFinish : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit EscrowFinish(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static bool
-    checkExtraFeatures(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static NotTEC
-    preflightSigValidated(PreflightContext const& ctx);
-
-    static XRPAmount
-    calculateBaseFee(ReadView const& view, STTx const& tx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-}  // namespace xrpl

include/xrpl/tx/transactors/payment_channel/PayChan.h

@@ -0,0 +1,83 @@
+#pragma once
+
+#include <xrpl/tx/Transactor.h>
+
+namespace xrpl {
+
+class PayChanCreate : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Custom};
+
+    explicit PayChanCreate(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static TxConsequences
+    makeTxConsequences(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+using PaymentChannelCreate = PayChanCreate;
+
+//------------------------------------------------------------------------------
+
+class PayChanFund : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Custom};
+
+    explicit PayChanFund(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static TxConsequences
+    makeTxConsequences(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+using PaymentChannelFund = PayChanFund;
+
+//------------------------------------------------------------------------------
+
+class PayChanClaim : public Transactor
+{
+public:
+    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
+
+    explicit PayChanClaim(ApplyContext& ctx) : Transactor(ctx)
+    {
+    }
+
+    static bool
+    checkExtraFeatures(PreflightContext const& ctx);
+
+    static std::uint32_t
+    getFlagsMask(PreflightContext const& ctx);
+
+    static NotTEC
+    preflight(PreflightContext const& ctx);
+
+    static TER
+    preclaim(PreclaimContext const& ctx);
+
+    TER
+    doApply() override;
+};
+
+using PaymentChannelClaim = PayChanClaim;
+
+}  // namespace xrpl

include/xrpl/tx/transactors/payment_channel/PayChanClaim.h

@@ -1,34 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class PayChanClaim : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Normal};
-
-    explicit PayChanClaim(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static bool
-    checkExtraFeatures(PreflightContext const& ctx);
-
-    static std::uint32_t
-    getFlagsMask(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-using PaymentChannelClaim = PayChanClaim;
-
-}  // namespace xrpl

include/xrpl/tx/transactors/payment_channel/PayChanCreate.h

@@ -1,31 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class PayChanCreate : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Custom};
-
-    explicit PayChanCreate(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static TxConsequences
-    makeTxConsequences(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    static TER
-    preclaim(PreclaimContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-using PaymentChannelCreate = PayChanCreate;
-
-}  // namespace xrpl

include/xrpl/tx/transactors/payment_channel/PayChanFund.h

@@ -1,28 +0,0 @@
-#pragma once
-
-#include <xrpl/tx/Transactor.h>
-
-namespace xrpl {
-
-class PayChanFund : public Transactor
-{
-public:
-    static constexpr ConsequencesFactoryType ConsequencesFactory{Custom};
-
-    explicit PayChanFund(ApplyContext& ctx) : Transactor(ctx)
-    {
-    }
-
-    static TxConsequences
-    makeTxConsequences(PreflightContext const& ctx);
-
-    static NotTEC
-    preflight(PreflightContext const& ctx);
-
-    TER
-    doApply() override;
-};
-
-using PaymentChannelFund = PayChanFund;
-
-}  // namespace xrpl

src/libxrpl/basics/base64.cpp

@@ -168,7 +168,7 @@ decode(void* dest, char const* src, std::size_t len)
             break;
         ++in;
         c4[i] = v;
-        if (++i == 4)
+        if (++i; i == 4)
         {
             c3[0] = (c4[0] << 2) + ((c4[1] & 0x30) >> 4);
             c3[1] = ((c4[1] & 0xf) << 4) + ((c4[2] & 0x3c) >> 2);

src/libxrpl/json/json_reader.cpp

@@ -729,21 +729,18 @@ Reader::decodeUnicodeCodePoint(Token& token, Location& current, Location end, un
 
         unsigned int surrogatePair;
 
-        if (*(current++) == '\\' && *(current++) == 'u')
-        {
-            if (decodeUnicodeEscapeSequence(token, current, end, surrogatePair))
-            {
-                unicode = 0x10000 + ((unicode & 0x3FF) << 10) + (surrogatePair & 0x3FF);
-            }
-            else
-                return false;
-        }
-        else
+        if (*current != '\\' || *(current + 1) != 'u')
             return addError(
-                "expecting another \\u token to begin the second half of a "
-                "unicode surrogate pair",
+                "expecting another \\u token to begin the second half of a unicode surrogate pair",
                 token,
                 current);
+
+        current += 2;  // skip two characters checked above
+
+        if (!decodeUnicodeEscapeSequence(token, current, end, surrogatePair))
+            return false;
+
+        unicode = 0x10000 + ((unicode & 0x3FF) << 10) + (surrogatePair & 0x3FF);
     }
 
     return true;

src/libxrpl/json/json_writer.cpp

@@ -319,7 +319,7 @@ StyledWriter::writeValue(Value const& value)
                     document_ += " : ";
                     writeValue(childValue);
 
-                    if (++it == members.end())
+                    if (++it; it == members.end())
                         break;
 
                     document_ += ",";

src/libxrpl/ledger/BookDirs.cpp

@@ -74,8 +74,10 @@ BookDirs::const_iterator::operator++()
     XRPL_ASSERT(index_ != zero, "xrpl::BookDirs::const_iterator::operator++ : nonzero index");
     if (!cdirNext(*view_, cur_key_, sle_, entry_, index_))
     {
-        if (index_ != 0 ||
-            (cur_key_ = view_->succ(++cur_key_, next_quality_).value_or(zero)) == zero)
+        if (index_ == 0)
+            cur_key_ = view_->succ(++cur_key_, next_quality_).value_or(zero);
+
+        if (index_ != 0 || cur_key_ == zero)
         {
             cur_key_ = key_;
             entry_ = 0;
@@ -84,9 +86,7 @@ BookDirs::const_iterator::operator++()
         else if (!cdirFirst(*view_, cur_key_, sle_, entry_, index_))
         {
             // LCOV_EXCL_START
-            UNREACHABLE(
-                "xrpl::BookDirs::const_iterator::operator++ : directory is "
-                "empty");
+            UNREACHABLE("xrpl::BookDirs::const_iterator::operator++ : directory is empty");
             // LCOV_EXCL_STOP
         }
     }

src/libxrpl/protocol/STBase.cpp

@@ -23,6 +23,9 @@ STBase::STBase(SField const& n) : fName(&n)
 STBase&
 STBase::operator=(STBase const& t)
 {
+    if (this == &t)
+        return *this;
+
     if (!fName->isUseful())
         fName = t.fName;
     return *this;

src/libxrpl/resource/Consumer.cpp

@@ -39,6 +39,9 @@ Consumer::~Consumer()
 Consumer&
 Consumer::operator=(Consumer const& other)
 {
+    if (this == &other)
+        return *this;
+
     // remove old ref
     if (m_logic && m_entry)
         m_logic->release(*m_entry);

src/libxrpl/tx/transactors/account/DeleteAccount.cpp

@@ -11,7 +11,7 @@
 #include <xrpl/tx/transactors/account/DeleteAccount.h>
 #include <xrpl/tx/transactors/account/SetSignerList.h>
 #include <xrpl/tx/transactors/delegate/DelegateSet.h>
-#include <xrpl/tx/transactors/did/DIDDelete.h>
+#include <xrpl/tx/transactors/did/DID.h>
 #include <xrpl/tx/transactors/nft/NFTokenUtils.h>
 #include <xrpl/tx/transactors/oracle/DeleteOracle.h>
 #include <xrpl/tx/transactors/payment/DepositPreauth.h>

src/libxrpl/tx/transactors/credentials/CredentialAccept.cpp

@@ -1,113 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/CredentialHelpers.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/TxFlags.h>
-#include <xrpl/tx/transactors/credentials/CredentialAccept.h>
-
-#include <chrono>
-
-namespace xrpl {
-
-using namespace credentials;
-
-std::uint32_t
-CredentialAccept::getFlagsMask(PreflightContext const& ctx)
-{
-    // 0 means "Allow any flags"
-    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
-}
-
-NotTEC
-CredentialAccept::preflight(PreflightContext const& ctx)
-{
-    if (!ctx.tx[sfIssuer])
-    {
-        JLOG(ctx.j.trace()) << "Malformed transaction: Issuer field zeroed.";
-        return temINVALID_ACCOUNT_ID;
-    }
-
-    auto const credType = ctx.tx[sfCredentialType];
-    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
-    {
-        JLOG(ctx.j.trace()) << "Malformed transaction: invalid size of CredentialType.";
-        return temMALFORMED;
-    }
-
-    return tesSUCCESS;
-}
-
-TER
-CredentialAccept::preclaim(PreclaimContext const& ctx)
-{
-    AccountID const subject = ctx.tx[sfAccount];
-    AccountID const issuer = ctx.tx[sfIssuer];
-    auto const credType(ctx.tx[sfCredentialType]);
-
-    if (!ctx.view.exists(keylet::account(issuer)))
-    {
-        JLOG(ctx.j.warn()) << "No issuer: " << to_string(issuer);
-        return tecNO_ISSUER;
-    }
-
-    auto const sleCred = ctx.view.read(keylet::credential(subject, issuer, credType));
-    if (!sleCred)
-    {
-        JLOG(ctx.j.warn()) << "No credential: " << to_string(subject) << ", " << to_string(issuer)
-                           << ", " << credType;
-        return tecNO_ENTRY;
-    }
-
-    if (sleCred->getFieldU32(sfFlags) & lsfAccepted)
-    {
-        JLOG(ctx.j.warn()) << "Credential already accepted: " << to_string(subject) << ", "
-                           << to_string(issuer) << ", " << credType;
-        return tecDUPLICATE;
-    }
-
-    return tesSUCCESS;
-}
-
-TER
-CredentialAccept::doApply()
-{
-    AccountID const issuer{ctx_.tx[sfIssuer]};
-
-    // Both exist as credential object exist itself (checked in preclaim)
-    auto const sleSubject = view().peek(keylet::account(account_));
-    auto const sleIssuer = view().peek(keylet::account(issuer));
-
-    if (!sleSubject || !sleIssuer)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    {
-        STAmount const reserve{
-            view().fees().accountReserve(sleSubject->getFieldU32(sfOwnerCount) + 1)};
-        if (mPriorBalance < reserve)
-            return tecINSUFFICIENT_RESERVE;
-    }
-
-    auto const credType(ctx_.tx[sfCredentialType]);
-    Keylet const credentialKey = keylet::credential(account_, issuer, credType);
-    auto const sleCred = view().peek(credentialKey);  // Checked in preclaim()
-
-    if (checkExpired(sleCred, view().header().parentCloseTime))
-    {
-        JLOG(j_.trace()) << "Credential is expired: " << sleCred->getText();
-        // delete expired credentials even if the transaction failed
-        auto const err = credentials::deleteSLE(view(), sleCred, j_);
-        return isTesSuccess(err) ? tecEXPIRED : err;
-    }
-
-    sleCred->setFieldU32(sfFlags, lsfAccepted);
-    view().update(sleCred);
-
-    adjustOwnerCount(view(), sleIssuer, -1, j_);
-    adjustOwnerCount(view(), sleSubject, 1, j_);
-
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/credentials/CredentialCreate.cpp

@@ -1,164 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/CredentialHelpers.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/TxFlags.h>
-#include <xrpl/tx/transactors/credentials/CredentialCreate.h>
-
-#include <chrono>
-
-namespace xrpl {
-
-/*
-    Credentials
-    ======
-
-   A verifiable credentials (VC
-   https://en.wikipedia.org/wiki/Verifiable_credentials), as defined by the W3C
-   specification (https://www.w3.org/TR/vc-data-model-2.0/), is a
-   secure and tamper-evident way to represent information about a subject, such
-   as an individual, organization, or even an IoT device. These credentials are
-   issued by a trusted entity and can be verified by third parties without
-   directly involving the issuer at all.
-*/
-
-using namespace credentials;
-
-std::uint32_t
-CredentialCreate::getFlagsMask(PreflightContext const& ctx)
-{
-    // 0 means "Allow any flags"
-    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
-}
-
-NotTEC
-CredentialCreate::preflight(PreflightContext const& ctx)
-{
-    auto const& tx = ctx.tx;
-    auto& j = ctx.j;
-
-    if (!tx[sfSubject])
-    {
-        JLOG(j.trace()) << "Malformed transaction: Invalid Subject";
-        return temMALFORMED;
-    }
-
-    auto const uri = tx[~sfURI];
-    if (uri && (uri->empty() || (uri->size() > maxCredentialURILength)))
-    {
-        JLOG(j.trace()) << "Malformed transaction: invalid size of URI.";
-        return temMALFORMED;
-    }
-
-    auto const credType = tx[sfCredentialType];
-    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
-    {
-        JLOG(j.trace()) << "Malformed transaction: invalid size of CredentialType.";
-        return temMALFORMED;
-    }
-
-    return tesSUCCESS;
-}
-
-TER
-CredentialCreate::preclaim(PreclaimContext const& ctx)
-{
-    auto const credType(ctx.tx[sfCredentialType]);
-    auto const subject = ctx.tx[sfSubject];
-
-    if (!ctx.view.exists(keylet::account(subject)))
-    {
-        JLOG(ctx.j.trace()) << "Subject doesn't exist.";
-        return tecNO_TARGET;
-    }
-
-    if (ctx.view.exists(keylet::credential(subject, ctx.tx[sfAccount], credType)))
-    {
-        JLOG(ctx.j.trace()) << "Credential already exists.";
-        return tecDUPLICATE;
-    }
-
-    return tesSUCCESS;
-}
-
-TER
-CredentialCreate::doApply()
-{
-    auto const subject = ctx_.tx[sfSubject];
-    auto const credType(ctx_.tx[sfCredentialType]);
-    Keylet const credentialKey = keylet::credential(subject, account_, credType);
-
-    auto const sleCred = std::make_shared<SLE>(credentialKey);
-    if (!sleCred)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    auto const optExp = ctx_.tx[~sfExpiration];
-    if (optExp)
-    {
-        std::uint32_t const closeTime =
-            ctx_.view().header().parentCloseTime.time_since_epoch().count();
-
-        if (closeTime > *optExp)
-        {
-            JLOG(j_.trace()) << "Malformed transaction: "
-                                "Expiration time is in the past.";
-            return tecEXPIRED;
-        }
-
-        sleCred->setFieldU32(sfExpiration, ctx_.tx.getFieldU32(sfExpiration));
-    }
-
-    auto const sleIssuer = view().peek(keylet::account(account_));
-    if (!sleIssuer)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    {
-        STAmount const reserve{
-            view().fees().accountReserve(sleIssuer->getFieldU32(sfOwnerCount) + 1)};
-        if (mPriorBalance < reserve)
-            return tecINSUFFICIENT_RESERVE;
-    }
-
-    sleCred->setAccountID(sfSubject, subject);
-    sleCred->setAccountID(sfIssuer, account_);
-    sleCred->setFieldVL(sfCredentialType, credType);
-
-    if (ctx_.tx.isFieldPresent(sfURI))
-        sleCred->setFieldVL(sfURI, ctx_.tx.getFieldVL(sfURI));
-
-    {
-        auto const page =
-            view().dirInsert(keylet::ownerDir(account_), credentialKey, describeOwnerDir(account_));
-        JLOG(j_.trace()) << "Adding Credential to owner directory " << to_string(credentialKey.key)
-                         << ": " << (page ? "success" : "failure");
-        if (!page)
-            return tecDIR_FULL;
-        sleCred->setFieldU64(sfIssuerNode, *page);
-
-        adjustOwnerCount(view(), sleIssuer, 1, j_);
-    }
-
-    if (subject == account_)
-    {
-        sleCred->setFieldU32(sfFlags, lsfAccepted);
-    }
-    else
-    {
-        auto const page =
-            view().dirInsert(keylet::ownerDir(subject), credentialKey, describeOwnerDir(subject));
-        JLOG(j_.trace()) << "Adding Credential to owner directory " << to_string(credentialKey.key)
-                         << ": " << (page ? "success" : "failure");
-        if (!page)
-            return tecDIR_FULL;
-        sleCred->setFieldU64(sfSubjectNode, *page);
-        view().update(view().peek(keylet::account(subject)));
-    }
-
-    view().insert(sleCred);
-
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/credentials/CredentialDelete.cpp

@@ -1,90 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/CredentialHelpers.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/TxFlags.h>
-#include <xrpl/tx/transactors/credentials/CredentialDelete.h>
-
-#include <chrono>
-
-namespace xrpl {
-
-using namespace credentials;
-
-std::uint32_t
-CredentialDelete::getFlagsMask(PreflightContext const& ctx)
-{
-    // 0 means "Allow any flags"
-    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
-}
-
-NotTEC
-CredentialDelete::preflight(PreflightContext const& ctx)
-{
-    auto const subject = ctx.tx[~sfSubject];
-    auto const issuer = ctx.tx[~sfIssuer];
-
-    if (!subject && !issuer)
-    {
-        // Neither field is present, the transaction is malformed.
-        JLOG(ctx.j.trace()) << "Malformed transaction: "
-                               "No Subject or Issuer fields.";
-        return temMALFORMED;
-    }
-
-    // Make sure that the passed account is valid.
-    if ((subject && subject->isZero()) || (issuer && issuer->isZero()))
-    {
-        JLOG(ctx.j.trace()) << "Malformed transaction: Subject or Issuer "
-                               "field zeroed.";
-        return temINVALID_ACCOUNT_ID;
-    }
-
-    auto const credType = ctx.tx[sfCredentialType];
-    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
-    {
-        JLOG(ctx.j.trace()) << "Malformed transaction: invalid size of CredentialType.";
-        return temMALFORMED;
-    }
-
-    return tesSUCCESS;
-}
-
-TER
-CredentialDelete::preclaim(PreclaimContext const& ctx)
-{
-    AccountID const account{ctx.tx[sfAccount]};
-    auto const subject = ctx.tx[~sfSubject].value_or(account);
-    auto const issuer = ctx.tx[~sfIssuer].value_or(account);
-    auto const credType(ctx.tx[sfCredentialType]);
-
-    if (!ctx.view.exists(keylet::credential(subject, issuer, credType)))
-        return tecNO_ENTRY;
-
-    return tesSUCCESS;
-}
-
-TER
-CredentialDelete::doApply()
-{
-    auto const subject = ctx_.tx[~sfSubject].value_or(account_);
-    auto const issuer = ctx_.tx[~sfIssuer].value_or(account_);
-
-    auto const credType(ctx_.tx[sfCredentialType]);
-    auto const sleCred = view().peek(keylet::credential(subject, issuer, credType));
-    if (!sleCred)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    if ((subject != account_) && (issuer != account_) &&
-        !checkExpired(sleCred, ctx_.view().header().parentCloseTime))
-    {
-        JLOG(j_.trace()) << "Can't delete non-expired credential.";
-        return tecNO_PERMISSION;
-    }
-
-    return deleteSLE(view(), sleCred, j_);
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/credentials/Credentials.cpp

@@ -0,0 +1,341 @@
+#include <xrpl/basics/Log.h>
+#include <xrpl/ledger/ApplyView.h>
+#include <xrpl/ledger/CredentialHelpers.h>
+#include <xrpl/ledger/View.h>
+#include <xrpl/protocol/Feature.h>
+#include <xrpl/protocol/Indexes.h>
+#include <xrpl/protocol/TxFlags.h>
+#include <xrpl/tx/transactors/credentials/Credentials.h>
+
+#include <chrono>
+
+namespace xrpl {
+
+/*
+    Credentials
+    ======
+
+   A verifiable credentials (VC
+   https://en.wikipedia.org/wiki/Verifiable_credentials), as defined by the W3C
+   specification (https://www.w3.org/TR/vc-data-model-2.0/), is a
+   secure and tamper-evident way to represent information about a subject, such
+   as an individual, organization, or even an IoT device. These credentials are
+   issued by a trusted entity and can be verified by third parties without
+   directly involving the issuer at all.
+*/
+
+using namespace credentials;
+
+// ------- CREATE --------------------------
+
+std::uint32_t
+CredentialCreate::getFlagsMask(PreflightContext const& ctx)
+{
+    // 0 means "Allow any flags"
+    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
+}
+
+NotTEC
+CredentialCreate::preflight(PreflightContext const& ctx)
+{
+    auto const& tx = ctx.tx;
+    auto& j = ctx.j;
+
+    if (!tx[sfSubject])
+    {
+        JLOG(j.trace()) << "Malformed transaction: Invalid Subject";
+        return temMALFORMED;
+    }
+
+    auto const uri = tx[~sfURI];
+    if (uri && (uri->empty() || (uri->size() > maxCredentialURILength)))
+    {
+        JLOG(j.trace()) << "Malformed transaction: invalid size of URI.";
+        return temMALFORMED;
+    }
+
+    auto const credType = tx[sfCredentialType];
+    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
+    {
+        JLOG(j.trace()) << "Malformed transaction: invalid size of CredentialType.";
+        return temMALFORMED;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+CredentialCreate::preclaim(PreclaimContext const& ctx)
+{
+    auto const credType(ctx.tx[sfCredentialType]);
+    auto const subject = ctx.tx[sfSubject];
+
+    if (!ctx.view.exists(keylet::account(subject)))
+    {
+        JLOG(ctx.j.trace()) << "Subject doesn't exist.";
+        return tecNO_TARGET;
+    }
+
+    if (ctx.view.exists(keylet::credential(subject, ctx.tx[sfAccount], credType)))
+    {
+        JLOG(ctx.j.trace()) << "Credential already exists.";
+        return tecDUPLICATE;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+CredentialCreate::doApply()
+{
+    auto const subject = ctx_.tx[sfSubject];
+    auto const credType(ctx_.tx[sfCredentialType]);
+    Keylet const credentialKey = keylet::credential(subject, account_, credType);
+
+    auto const sleCred = std::make_shared<SLE>(credentialKey);
+    if (!sleCred)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    auto const optExp = ctx_.tx[~sfExpiration];
+    if (optExp)
+    {
+        std::uint32_t const closeTime =
+            ctx_.view().header().parentCloseTime.time_since_epoch().count();
+
+        if (closeTime > *optExp)
+        {
+            JLOG(j_.trace()) << "Malformed transaction: "
+                                "Expiration time is in the past.";
+            return tecEXPIRED;
+        }
+
+        sleCred->setFieldU32(sfExpiration, ctx_.tx.getFieldU32(sfExpiration));
+    }
+
+    auto const sleIssuer = view().peek(keylet::account(account_));
+    if (!sleIssuer)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    {
+        STAmount const reserve{
+            view().fees().accountReserve(sleIssuer->getFieldU32(sfOwnerCount) + 1)};
+        if (mPriorBalance < reserve)
+            return tecINSUFFICIENT_RESERVE;
+    }
+
+    sleCred->setAccountID(sfSubject, subject);
+    sleCred->setAccountID(sfIssuer, account_);
+    sleCred->setFieldVL(sfCredentialType, credType);
+
+    if (ctx_.tx.isFieldPresent(sfURI))
+        sleCred->setFieldVL(sfURI, ctx_.tx.getFieldVL(sfURI));
+
+    {
+        auto const page =
+            view().dirInsert(keylet::ownerDir(account_), credentialKey, describeOwnerDir(account_));
+        JLOG(j_.trace()) << "Adding Credential to owner directory " << to_string(credentialKey.key)
+                         << ": " << (page ? "success" : "failure");
+        if (!page)
+            return tecDIR_FULL;
+        sleCred->setFieldU64(sfIssuerNode, *page);
+
+        adjustOwnerCount(view(), sleIssuer, 1, j_);
+    }
+
+    if (subject == account_)
+    {
+        sleCred->setFieldU32(sfFlags, lsfAccepted);
+    }
+    else
+    {
+        auto const page =
+            view().dirInsert(keylet::ownerDir(subject), credentialKey, describeOwnerDir(subject));
+        JLOG(j_.trace()) << "Adding Credential to owner directory " << to_string(credentialKey.key)
+                         << ": " << (page ? "success" : "failure");
+        if (!page)
+            return tecDIR_FULL;
+        sleCred->setFieldU64(sfSubjectNode, *page);
+        view().update(view().peek(keylet::account(subject)));
+    }
+
+    view().insert(sleCred);
+
+    return tesSUCCESS;
+}
+
+// ------- DELETE --------------------------
+
+std::uint32_t
+CredentialDelete::getFlagsMask(PreflightContext const& ctx)
+{
+    // 0 means "Allow any flags"
+    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
+}
+
+NotTEC
+CredentialDelete::preflight(PreflightContext const& ctx)
+{
+    auto const subject = ctx.tx[~sfSubject];
+    auto const issuer = ctx.tx[~sfIssuer];
+
+    if (!subject && !issuer)
+    {
+        // Neither field is present, the transaction is malformed.
+        JLOG(ctx.j.trace()) << "Malformed transaction: "
+                               "No Subject or Issuer fields.";
+        return temMALFORMED;
+    }
+
+    // Make sure that the passed account is valid.
+    if ((subject && subject->isZero()) || (issuer && issuer->isZero()))
+    {
+        JLOG(ctx.j.trace()) << "Malformed transaction: Subject or Issuer "
+                               "field zeroed.";
+        return temINVALID_ACCOUNT_ID;
+    }
+
+    auto const credType = ctx.tx[sfCredentialType];
+    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
+    {
+        JLOG(ctx.j.trace()) << "Malformed transaction: invalid size of CredentialType.";
+        return temMALFORMED;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+CredentialDelete::preclaim(PreclaimContext const& ctx)
+{
+    AccountID const account{ctx.tx[sfAccount]};
+    auto const subject = ctx.tx[~sfSubject].value_or(account);
+    auto const issuer = ctx.tx[~sfIssuer].value_or(account);
+    auto const credType(ctx.tx[sfCredentialType]);
+
+    if (!ctx.view.exists(keylet::credential(subject, issuer, credType)))
+        return tecNO_ENTRY;
+
+    return tesSUCCESS;
+}
+
+TER
+CredentialDelete::doApply()
+{
+    auto const subject = ctx_.tx[~sfSubject].value_or(account_);
+    auto const issuer = ctx_.tx[~sfIssuer].value_or(account_);
+
+    auto const credType(ctx_.tx[sfCredentialType]);
+    auto const sleCred = view().peek(keylet::credential(subject, issuer, credType));
+    if (!sleCred)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    if ((subject != account_) && (issuer != account_) &&
+        !checkExpired(sleCred, ctx_.view().header().parentCloseTime))
+    {
+        JLOG(j_.trace()) << "Can't delete non-expired credential.";
+        return tecNO_PERMISSION;
+    }
+
+    return deleteSLE(view(), sleCred, j_);
+}
+
+// ------- APPLY --------------------------
+
+std::uint32_t
+CredentialAccept::getFlagsMask(PreflightContext const& ctx)
+{
+    // 0 means "Allow any flags"
+    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
+}
+
+NotTEC
+CredentialAccept::preflight(PreflightContext const& ctx)
+{
+    if (!ctx.tx[sfIssuer])
+    {
+        JLOG(ctx.j.trace()) << "Malformed transaction: Issuer field zeroed.";
+        return temINVALID_ACCOUNT_ID;
+    }
+
+    auto const credType = ctx.tx[sfCredentialType];
+    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
+    {
+        JLOG(ctx.j.trace()) << "Malformed transaction: invalid size of CredentialType.";
+        return temMALFORMED;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+CredentialAccept::preclaim(PreclaimContext const& ctx)
+{
+    AccountID const subject = ctx.tx[sfAccount];
+    AccountID const issuer = ctx.tx[sfIssuer];
+    auto const credType(ctx.tx[sfCredentialType]);
+
+    if (!ctx.view.exists(keylet::account(issuer)))
+    {
+        JLOG(ctx.j.warn()) << "No issuer: " << to_string(issuer);
+        return tecNO_ISSUER;
+    }
+
+    auto const sleCred = ctx.view.read(keylet::credential(subject, issuer, credType));
+    if (!sleCred)
+    {
+        JLOG(ctx.j.warn()) << "No credential: " << to_string(subject) << ", " << to_string(issuer)
+                           << ", " << credType;
+        return tecNO_ENTRY;
+    }
+
+    if (sleCred->getFieldU32(sfFlags) & lsfAccepted)
+    {
+        JLOG(ctx.j.warn()) << "Credential already accepted: " << to_string(subject) << ", "
+                           << to_string(issuer) << ", " << credType;
+        return tecDUPLICATE;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+CredentialAccept::doApply()
+{
+    AccountID const issuer{ctx_.tx[sfIssuer]};
+
+    // Both exist as credential object exist itself (checked in preclaim)
+    auto const sleSubject = view().peek(keylet::account(account_));
+    auto const sleIssuer = view().peek(keylet::account(issuer));
+
+    if (!sleSubject || !sleIssuer)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    {
+        STAmount const reserve{
+            view().fees().accountReserve(sleSubject->getFieldU32(sfOwnerCount) + 1)};
+        if (mPriorBalance < reserve)
+            return tecINSUFFICIENT_RESERVE;
+    }
+
+    auto const credType(ctx_.tx[sfCredentialType]);
+    Keylet const credentialKey = keylet::credential(account_, issuer, credType);
+    auto const sleCred = view().peek(credentialKey);  // Checked in preclaim()
+
+    if (checkExpired(sleCred, view().header().parentCloseTime))
+    {
+        JLOG(j_.trace()) << "Credential is expired: " << sleCred->getText();
+        // delete expired credentials even if the transaction failed
+        auto const err = credentials::deleteSLE(view(), sleCred, j_);
+        return isTesSuccess(err) ? tecEXPIRED : err;
+    }
+
+    sleCred->setFieldU32(sfFlags, lsfAccepted);
+    view().update(sleCred);
+
+    adjustOwnerCount(view(), sleIssuer, -1, j_);
+    adjustOwnerCount(view(), sleSubject, 1, j_);
+
+    return tesSUCCESS;
+}
+
+}  // namespace xrpl

src/libxrpl/tx/transactors/did/DID.cpp

@@ -4,7 +4,7 @@
 #include <xrpl/protocol/Feature.h>
 #include <xrpl/protocol/Indexes.h>
 #include <xrpl/protocol/TxFlags.h>
-#include <xrpl/tx/transactors/did/DIDSet.h>
+#include <xrpl/tx/transactors/did/DID.h>
 
 namespace xrpl {
 
@@ -134,4 +134,54 @@ DIDSet::doApply()
     return addSLE(ctx_, sleDID, account_);
 }
 
+NotTEC
+DIDDelete::preflight(PreflightContext const& ctx)
+{
+    return tesSUCCESS;
+}
+
+TER
+DIDDelete::deleteSLE(ApplyContext& ctx, Keylet sleKeylet, AccountID const owner)
+{
+    auto const sle = ctx.view().peek(sleKeylet);
+    if (!sle)
+        return tecNO_ENTRY;
+
+    return DIDDelete::deleteSLE(ctx.view(), sle, owner, ctx.journal);
+}
+
+TER
+DIDDelete::deleteSLE(
+    ApplyView& view,
+    std::shared_ptr<SLE> sle,
+    AccountID const owner,
+    beast::Journal j)
+{
+    // Remove object from owner directory
+    if (!view.dirRemove(keylet::ownerDir(owner), (*sle)[sfOwnerNode], sle->key(), true))
+    {
+        // LCOV_EXCL_START
+        JLOG(j.fatal()) << "Unable to delete DID Token from owner.";
+        return tefBAD_LEDGER;
+        // LCOV_EXCL_STOP
+    }
+
+    auto const sleOwner = view.peek(keylet::account(owner));
+    if (!sleOwner)
+        return tecINTERNAL;  // LCOV_EXCL_LINE
+
+    adjustOwnerCount(view, sleOwner, -1, j);
+    view.update(sleOwner);
+
+    // Remove object from ledger
+    view.erase(sle);
+    return tesSUCCESS;
+}
+
+TER
+DIDDelete::doApply()
+{
+    return deleteSLE(ctx_, keylet::did(account_), account_);
+}
+
 }  // namespace xrpl

src/libxrpl/tx/transactors/did/DIDDelete.cpp

@@ -1,59 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/tx/transactors/did/DIDDelete.h>
-
-namespace xrpl {
-
-NotTEC
-DIDDelete::preflight(PreflightContext const& ctx)
-{
-    return tesSUCCESS;
-}
-
-TER
-DIDDelete::deleteSLE(ApplyContext& ctx, Keylet sleKeylet, AccountID const owner)
-{
-    auto const sle = ctx.view().peek(sleKeylet);
-    if (!sle)
-        return tecNO_ENTRY;
-
-    return DIDDelete::deleteSLE(ctx.view(), sle, owner, ctx.journal);
-}
-
-TER
-DIDDelete::deleteSLE(
-    ApplyView& view,
-    std::shared_ptr<SLE> sle,
-    AccountID const owner,
-    beast::Journal j)
-{
-    // Remove object from owner directory
-    if (!view.dirRemove(keylet::ownerDir(owner), (*sle)[sfOwnerNode], sle->key(), true))
-    {
-        // LCOV_EXCL_START
-        JLOG(j.fatal()) << "Unable to delete DID Token from owner.";
-        return tefBAD_LEDGER;
-        // LCOV_EXCL_STOP
-    }
-
-    auto const sleOwner = view.peek(keylet::account(owner));
-    if (!sleOwner)
-        return tecINTERNAL;  // LCOV_EXCL_LINE
-
-    adjustOwnerCount(view, sleOwner, -1, j);
-    view.update(sleOwner);
-
-    // Remove object from ledger
-    view.erase(sle);
-    return tesSUCCESS;
-}
-
-TER
-DIDDelete::doApply()
-{
-    return deleteSLE(ctx_, keylet::did(account_), account_);
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/escrow/EscrowCancel.cpp

@@ -1,201 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/tx/transactors/escrow/EscrowCancel.h>
-
-#include <libxrpl/tx/transactors/escrow/EscrowHelpers.h>
-
-namespace xrpl {
-
-NotTEC
-EscrowCancel::preflight(PreflightContext const& ctx)
-{
-    return tesSUCCESS;
-}
-
-template <ValidIssueType T>
-static TER
-escrowCancelPreclaimHelper(
-    PreclaimContext const& ctx,
-    AccountID const& account,
-    STAmount const& amount);
-
-template <>
-TER
-escrowCancelPreclaimHelper<Issue>(
-    PreclaimContext const& ctx,
-    AccountID const& account,
-    STAmount const& amount)
-{
-    AccountID issuer = amount.getIssuer();
-    // If the issuer is the same as the account, return tecINTERNAL
-    if (issuer == account)
-        return tecINTERNAL;  // LCOV_EXCL_LINE
-
-    // If the issuer has requireAuth set, check if the account is authorized
-    if (auto const ter = requireAuth(ctx.view, amount.issue(), account); ter != tesSUCCESS)
-        return ter;
-
-    return tesSUCCESS;
-}
-
-template <>
-TER
-escrowCancelPreclaimHelper<MPTIssue>(
-    PreclaimContext const& ctx,
-    AccountID const& account,
-    STAmount const& amount)
-{
-    AccountID issuer = amount.getIssuer();
-    // If the issuer is the same as the account, return tecINTERNAL
-    if (issuer == account)
-        return tecINTERNAL;  // LCOV_EXCL_LINE
-
-    // If the mpt does not exist, return tecOBJECT_NOT_FOUND
-    auto const issuanceKey = keylet::mptIssuance(amount.get<MPTIssue>().getMptID());
-    auto const sleIssuance = ctx.view.read(issuanceKey);
-    if (!sleIssuance)
-        return tecOBJECT_NOT_FOUND;
-
-    // If the issuer has requireAuth set, check if the account is
-    // authorized
-    auto const& mptIssue = amount.get<MPTIssue>();
-    if (auto const ter = requireAuth(ctx.view, mptIssue, account, AuthType::WeakAuth);
-        ter != tesSUCCESS)
-        return ter;
-
-    return tesSUCCESS;
-}
-
-TER
-EscrowCancel::preclaim(PreclaimContext const& ctx)
-{
-    if (ctx.view.rules().enabled(featureTokenEscrow))
-    {
-        auto const k = keylet::escrow(ctx.tx[sfOwner], ctx.tx[sfOfferSequence]);
-        auto const slep = ctx.view.read(k);
-        if (!slep)
-            return tecNO_TARGET;
-
-        AccountID const account = (*slep)[sfAccount];
-        STAmount const amount = (*slep)[sfAmount];
-
-        if (!isXRP(amount))
-        {
-            if (auto const ret = std::visit(
-                    [&]<typename T>(T const&) {
-                        return escrowCancelPreclaimHelper<T>(ctx, account, amount);
-                    },
-                    amount.asset().value());
-                !isTesSuccess(ret))
-                return ret;
-        }
-    }
-    return tesSUCCESS;
-}
-
-TER
-EscrowCancel::doApply()
-{
-    auto const k = keylet::escrow(ctx_.tx[sfOwner], ctx_.tx[sfOfferSequence]);
-    auto const slep = ctx_.view().peek(k);
-    if (!slep)
-    {
-        if (ctx_.view().rules().enabled(featureTokenEscrow))
-            return tecINTERNAL;  // LCOV_EXCL_LINE
-
-        return tecNO_TARGET;
-    }
-
-    auto const now = ctx_.view().header().parentCloseTime;
-
-    // No cancel time specified: can't execute at all.
-    if (!(*slep)[~sfCancelAfter])
-        return tecNO_PERMISSION;
-
-    // Too soon: can't execute before the cancel time.
-    if (!after(now, (*slep)[sfCancelAfter]))
-        return tecNO_PERMISSION;
-
-    AccountID const account = (*slep)[sfAccount];
-
-    // Remove escrow from owner directory
-    {
-        auto const page = (*slep)[sfOwnerNode];
-        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, k.key, true))
-        {
-            // LCOV_EXCL_START
-            JLOG(j_.fatal()) << "Unable to delete Escrow from owner.";
-            return tefBAD_LEDGER;
-            // LCOV_EXCL_STOP
-        }
-    }
-
-    // Remove escrow from recipient's owner directory, if present.
-    if (auto const optPage = (*slep)[~sfDestinationNode]; optPage)
-    {
-        if (!ctx_.view().dirRemove(keylet::ownerDir((*slep)[sfDestination]), *optPage, k.key, true))
-        {
-            // LCOV_EXCL_START
-            JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
-            return tefBAD_LEDGER;
-            // LCOV_EXCL_STOP
-        }
-    }
-
-    auto const sle = ctx_.view().peek(keylet::account(account));
-    STAmount const amount = slep->getFieldAmount(sfAmount);
-
-    // Transfer amount back to the owner
-    if (isXRP(amount))
-        (*sle)[sfBalance] = (*sle)[sfBalance] + amount;
-    else
-    {
-        if (!ctx_.view().rules().enabled(featureTokenEscrow))
-            return temDISABLED;  // LCOV_EXCL_LINE
-
-        auto const issuer = amount.getIssuer();
-        bool const createAsset = account == account_;
-        if (auto const ret = std::visit(
-                [&]<typename T>(T const&) {
-                    return escrowUnlockApplyHelper<T>(
-                        ctx_.view(),
-                        parityRate,
-                        slep,
-                        mPriorBalance,
-                        amount,
-                        issuer,
-                        account,  // sender and receiver are the same
-                        account,
-                        createAsset,
-                        j_);
-                },
-                amount.asset().value());
-            !isTesSuccess(ret))
-            return ret;  // LCOV_EXCL_LINE
-
-        // Remove escrow from issuers owner directory, if present.
-        if (auto const optPage = (*slep)[~sfIssuerNode]; optPage)
-        {
-            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, k.key, true))
-            {
-                // LCOV_EXCL_START
-                JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
-                return tefBAD_LEDGER;
-                // LCOV_EXCL_STOP
-            }
-        }
-    }
-
-    adjustOwnerCount(ctx_.view(), sle, -1, ctx_.journal);
-    ctx_.view().update(sle);
-
-    // Remove escrow from ledger
-    ctx_.view().erase(slep);
-
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/escrow/EscrowCreate.cpp

@@ -1,498 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/basics/chrono.h>
-#include <xrpl/conditions/Condition.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/MPTAmount.h>
-#include <xrpl/protocol/TxFlags.h>
-#include <xrpl/protocol/XRPAmount.h>
-#include <xrpl/tx/transactors/escrow/EscrowCreate.h>
-
-namespace xrpl {
-
-/*
-    Escrow
-    ======
-
-    Escrow is a feature of the XRP Ledger that allows you to send conditional
-    XRP payments. These conditional payments, called escrows, set aside XRP and
-    deliver it later when certain conditions are met. Conditions to successfully
-    finish an escrow include time-based unlocks and crypto-conditions. Escrows
-    can also be set to expire if not finished in time.
-
-    The XRP set aside in an escrow is locked up. No one can use or destroy the
-    XRP until the escrow has been successfully finished or canceled. Before the
-    expiration time, only the intended receiver can get the XRP. After the
-    expiration time, the XRP can only be returned to the sender.
-
-    For more details on escrow, including examples, diagrams and more please
-    visit https://xrpl.org/escrow.html
-
-    For details on specific transactions, including fields and validation rules
-    please see:
-
-    `EscrowCreate`
-    --------------
-        See: https://xrpl.org/escrowcreate.html
-
-    `EscrowFinish`
-    --------------
-        See: https://xrpl.org/escrowfinish.html
-
-    `EscrowCancel`
-    --------------
-        See: https://xrpl.org/escrowcancel.html
-*/
-
-//------------------------------------------------------------------------------
-
-TxConsequences
-EscrowCreate::makeTxConsequences(PreflightContext const& ctx)
-{
-    auto const amount = ctx.tx[sfAmount];
-    return TxConsequences{ctx.tx, isXRP(amount) ? amount.xrp() : beast::zero};
-}
-
-template <ValidIssueType T>
-static NotTEC
-escrowCreatePreflightHelper(PreflightContext const& ctx);
-
-template <>
-NotTEC
-escrowCreatePreflightHelper<Issue>(PreflightContext const& ctx)
-{
-    STAmount const amount = ctx.tx[sfAmount];
-    if (amount.native() || amount <= beast::zero)
-        return temBAD_AMOUNT;
-
-    if (badCurrency() == amount.getCurrency())
-        return temBAD_CURRENCY;
-
-    return tesSUCCESS;
-}
-
-template <>
-NotTEC
-escrowCreatePreflightHelper<MPTIssue>(PreflightContext const& ctx)
-{
-    if (!ctx.rules.enabled(featureMPTokensV1))
-        return temDISABLED;
-
-    auto const amount = ctx.tx[sfAmount];
-    if (amount.native() || amount.mpt() > MPTAmount{maxMPTokenAmount} || amount <= beast::zero)
-        return temBAD_AMOUNT;
-
-    return tesSUCCESS;
-}
-
-NotTEC
-EscrowCreate::preflight(PreflightContext const& ctx)
-{
-    STAmount const amount{ctx.tx[sfAmount]};
-    if (!isXRP(amount))
-    {
-        if (!ctx.rules.enabled(featureTokenEscrow))
-            return temBAD_AMOUNT;
-
-        if (auto const ret = std::visit(
-                [&]<typename T>(T const&) { return escrowCreatePreflightHelper<T>(ctx); },
-                amount.asset().value());
-            !isTesSuccess(ret))
-            return ret;
-    }
-    else
-    {
-        if (amount <= beast::zero)
-            return temBAD_AMOUNT;
-    }
-
-    // We must specify at least one timeout value
-    if (!ctx.tx[~sfCancelAfter] && !ctx.tx[~sfFinishAfter])
-        return temBAD_EXPIRATION;
-
-    // If both finish and cancel times are specified then the cancel time must
-    // be strictly after the finish time.
-    if (ctx.tx[~sfCancelAfter] && ctx.tx[~sfFinishAfter] &&
-        ctx.tx[sfCancelAfter] <= ctx.tx[sfFinishAfter])
-        return temBAD_EXPIRATION;
-
-    // In the absence of a FinishAfter, the escrow can be finished
-    // immediately, which can be confusing. When creating an escrow,
-    // we want to ensure that either a FinishAfter time is explicitly
-    // specified or a completion condition is attached.
-    if (!ctx.tx[~sfFinishAfter] && !ctx.tx[~sfCondition])
-        return temMALFORMED;
-
-    if (auto const cb = ctx.tx[~sfCondition])
-    {
-        using namespace xrpl::cryptoconditions;
-
-        std::error_code ec;
-
-        auto condition = Condition::deserialize(*cb, ec);
-        if (!condition)
-        {
-            JLOG(ctx.j.debug()) << "Malformed condition during escrow creation: " << ec.message();
-            return temMALFORMED;
-        }
-    }
-
-    return tesSUCCESS;
-}
-
-template <ValidIssueType T>
-static TER
-escrowCreatePreclaimHelper(
-    PreclaimContext const& ctx,
-    AccountID const& account,
-    AccountID const& dest,
-    STAmount const& amount);
-
-template <>
-TER
-escrowCreatePreclaimHelper<Issue>(
-    PreclaimContext const& ctx,
-    AccountID const& account,
-    AccountID const& dest,
-    STAmount const& amount)
-{
-    AccountID issuer = amount.getIssuer();
-    // If the issuer is the same as the account, return tecNO_PERMISSION
-    if (issuer == account)
-        return tecNO_PERMISSION;
-
-    // If the lsfAllowTrustLineLocking is not enabled, return tecNO_PERMISSION
-    auto const sleIssuer = ctx.view.read(keylet::account(issuer));
-    if (!sleIssuer)
-        return tecNO_ISSUER;
-    if (!sleIssuer->isFlag(lsfAllowTrustLineLocking))
-        return tecNO_PERMISSION;
-
-    // If the account does not have a trustline to the issuer, return tecNO_LINE
-    auto const sleRippleState = ctx.view.read(keylet::line(account, issuer, amount.getCurrency()));
-    if (!sleRippleState)
-        return tecNO_LINE;
-
-    STAmount const balance = (*sleRippleState)[sfBalance];
-
-    // If balance is positive, issuer must have higher address than account
-    if (balance > beast::zero && issuer < account)
-        return tecNO_PERMISSION;  // LCOV_EXCL_LINE
-
-    // If balance is negative, issuer must have lower address than account
-    if (balance < beast::zero && issuer > account)
-        return tecNO_PERMISSION;  // LCOV_EXCL_LINE
-
-    // If the issuer has requireAuth set, check if the account is authorized
-    if (auto const ter = requireAuth(ctx.view, amount.issue(), account); ter != tesSUCCESS)
-        return ter;
-
-    // If the issuer has requireAuth set, check if the destination is authorized
-    if (auto const ter = requireAuth(ctx.view, amount.issue(), dest); ter != tesSUCCESS)
-        return ter;
-
-    // If the issuer has frozen the account, return tecFROZEN
-    if (isFrozen(ctx.view, account, amount.issue()))
-        return tecFROZEN;
-
-    // If the issuer has frozen the destination, return tecFROZEN
-    if (isFrozen(ctx.view, dest, amount.issue()))
-        return tecFROZEN;
-
-    STAmount const spendableAmount =
-        accountHolds(ctx.view, account, amount.getCurrency(), issuer, fhIGNORE_FREEZE, ctx.j);
-
-    // If the balance is less than or equal to 0, return tecINSUFFICIENT_FUNDS
-    if (spendableAmount <= beast::zero)
-        return tecINSUFFICIENT_FUNDS;
-
-    // If the spendable amount is less than the amount, return
-    // tecINSUFFICIENT_FUNDS
-    if (spendableAmount < amount)
-        return tecINSUFFICIENT_FUNDS;
-
-    // If the amount is not addable to the balance, return tecPRECISION_LOSS
-    if (!canAdd(spendableAmount, amount))
-        return tecPRECISION_LOSS;
-
-    return tesSUCCESS;
-}
-
-template <>
-TER
-escrowCreatePreclaimHelper<MPTIssue>(
-    PreclaimContext const& ctx,
-    AccountID const& account,
-    AccountID const& dest,
-    STAmount const& amount)
-{
-    AccountID issuer = amount.getIssuer();
-    // If the issuer is the same as the account, return tecNO_PERMISSION
-    if (issuer == account)
-        return tecNO_PERMISSION;
-
-    // If the mpt does not exist, return tecOBJECT_NOT_FOUND
-    auto const issuanceKey = keylet::mptIssuance(amount.get<MPTIssue>().getMptID());
-    auto const sleIssuance = ctx.view.read(issuanceKey);
-    if (!sleIssuance)
-        return tecOBJECT_NOT_FOUND;
-
-    // If the lsfMPTCanEscrow is not enabled, return tecNO_PERMISSION
-    if (!sleIssuance->isFlag(lsfMPTCanEscrow))
-        return tecNO_PERMISSION;
-
-    // If the issuer is not the same as the issuer of the mpt, return
-    // tecNO_PERMISSION
-    if (sleIssuance->getAccountID(sfIssuer) != issuer)
-        return tecNO_PERMISSION;  // LCOV_EXCL_LINE
-
-    // If the account does not have the mpt, return tecOBJECT_NOT_FOUND
-    if (!ctx.view.exists(keylet::mptoken(issuanceKey.key, account)))
-        return tecOBJECT_NOT_FOUND;
-
-    // If the issuer has requireAuth set, check if the account is
-    // authorized
-    auto const& mptIssue = amount.get<MPTIssue>();
-    if (auto const ter = requireAuth(ctx.view, mptIssue, account, AuthType::WeakAuth);
-        ter != tesSUCCESS)
-        return ter;
-
-    // If the issuer has requireAuth set, check if the destination is
-    // authorized
-    if (auto const ter = requireAuth(ctx.view, mptIssue, dest, AuthType::WeakAuth);
-        ter != tesSUCCESS)
-        return ter;
-
-    // If the issuer has frozen the account, return tecLOCKED
-    if (isFrozen(ctx.view, account, mptIssue))
-        return tecLOCKED;
-
-    // If the issuer has frozen the destination, return tecLOCKED
-    if (isFrozen(ctx.view, dest, mptIssue))
-        return tecLOCKED;
-
-    // If the mpt cannot be transferred, return tecNO_AUTH
-    if (auto const ter = canTransfer(ctx.view, mptIssue, account, dest); ter != tesSUCCESS)
-        return ter;
-
-    STAmount const spendableAmount = accountHolds(
-        ctx.view, account, amount.get<MPTIssue>(), fhIGNORE_FREEZE, ahIGNORE_AUTH, ctx.j);
-
-    // If the balance is less than or equal to 0, return tecINSUFFICIENT_FUNDS
-    if (spendableAmount <= beast::zero)
-        return tecINSUFFICIENT_FUNDS;
-
-    // If the spendable amount is less than the amount, return
-    // tecINSUFFICIENT_FUNDS
-    if (spendableAmount < amount)
-        return tecINSUFFICIENT_FUNDS;
-
-    return tesSUCCESS;
-}
-
-TER
-EscrowCreate::preclaim(PreclaimContext const& ctx)
-{
-    STAmount const amount{ctx.tx[sfAmount]};
-    AccountID const account{ctx.tx[sfAccount]};
-    AccountID const dest{ctx.tx[sfDestination]};
-
-    auto const sled = ctx.view.read(keylet::account(dest));
-    if (!sled)
-        return tecNO_DST;
-
-    // Pseudo-accounts cannot receive escrow. Note, this is not amendment-gated
-    // because all writes to pseudo-account discriminator fields **are**
-    // amendment gated, hence the behaviour of this check will always match the
-    // currently active amendments.
-    if (isPseudoAccount(sled))
-        return tecNO_PERMISSION;
-
-    if (!isXRP(amount))
-    {
-        if (!ctx.view.rules().enabled(featureTokenEscrow))
-            return temDISABLED;  // LCOV_EXCL_LINE
-
-        if (auto const ret = std::visit(
-                [&]<typename T>(T const&) {
-                    return escrowCreatePreclaimHelper<T>(ctx, account, dest, amount);
-                },
-                amount.asset().value());
-            !isTesSuccess(ret))
-            return ret;
-    }
-    return tesSUCCESS;
-}
-
-template <ValidIssueType T>
-static TER
-escrowLockApplyHelper(
-    ApplyView& view,
-    AccountID const& issuer,
-    AccountID const& sender,
-    STAmount const& amount,
-    beast::Journal journal);
-
-template <>
-TER
-escrowLockApplyHelper<Issue>(
-    ApplyView& view,
-    AccountID const& issuer,
-    AccountID const& sender,
-    STAmount const& amount,
-    beast::Journal journal)
-{
-    // Defensive: Issuer cannot create an escrow
-    if (issuer == sender)
-        return tecINTERNAL;  // LCOV_EXCL_LINE
-
-    auto const ter = rippleCredit(
-        view, sender, issuer, amount, amount.holds<MPTIssue>() ? false : true, journal);
-    if (ter != tesSUCCESS)
-        return ter;  // LCOV_EXCL_LINE
-    return tesSUCCESS;
-}
-
-template <>
-TER
-escrowLockApplyHelper<MPTIssue>(
-    ApplyView& view,
-    AccountID const& issuer,
-    AccountID const& sender,
-    STAmount const& amount,
-    beast::Journal journal)
-{
-    // Defensive: Issuer cannot create an escrow
-    if (issuer == sender)
-        return tecINTERNAL;  // LCOV_EXCL_LINE
-
-    auto const ter = rippleLockEscrowMPT(view, sender, amount, journal);
-    if (ter != tesSUCCESS)
-        return ter;  // LCOV_EXCL_LINE
-    return tesSUCCESS;
-}
-
-TER
-EscrowCreate::doApply()
-{
-    auto const closeTime = ctx_.view().header().parentCloseTime;
-
-    if (ctx_.tx[~sfCancelAfter] && after(closeTime, ctx_.tx[sfCancelAfter]))
-        return tecNO_PERMISSION;
-
-    if (ctx_.tx[~sfFinishAfter] && after(closeTime, ctx_.tx[sfFinishAfter]))
-        return tecNO_PERMISSION;
-
-    auto const sle = ctx_.view().peek(keylet::account(account_));
-    if (!sle)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    // Check reserve and funds availability
-    STAmount const amount{ctx_.tx[sfAmount]};
-
-    auto const reserve = ctx_.view().fees().accountReserve((*sle)[sfOwnerCount] + 1);
-
-    if (mSourceBalance < reserve)
-        return tecINSUFFICIENT_RESERVE;
-
-    // Check reserve and funds availability
-    if (isXRP(amount))
-    {
-        if (mSourceBalance < reserve + STAmount(amount).xrp())
-            return tecUNFUNDED;
-    }
-
-    // Check destination account
-    {
-        auto const sled = ctx_.view().read(keylet::account(ctx_.tx[sfDestination]));
-        if (!sled)
-            return tecNO_DST;  // LCOV_EXCL_LINE
-        if (((*sled)[sfFlags] & lsfRequireDestTag) && !ctx_.tx[~sfDestinationTag])
-            return tecDST_TAG_NEEDED;
-    }
-
-    // Create escrow in ledger.  Note that we we use the value from the
-    // sequence or ticket.  For more explanation see comments in SeqProxy.h.
-    Keylet const escrowKeylet = keylet::escrow(account_, ctx_.tx.getSeqValue());
-    auto const slep = std::make_shared<SLE>(escrowKeylet);
-    (*slep)[sfAmount] = amount;
-    (*slep)[sfAccount] = account_;
-    (*slep)[~sfCondition] = ctx_.tx[~sfCondition];
-    (*slep)[~sfSourceTag] = ctx_.tx[~sfSourceTag];
-    (*slep)[sfDestination] = ctx_.tx[sfDestination];
-    (*slep)[~sfCancelAfter] = ctx_.tx[~sfCancelAfter];
-    (*slep)[~sfFinishAfter] = ctx_.tx[~sfFinishAfter];
-    (*slep)[~sfDestinationTag] = ctx_.tx[~sfDestinationTag];
-
-    if (ctx_.view().rules().enabled(fixIncludeKeyletFields))
-    {
-        (*slep)[sfSequence] = ctx_.tx.getSeqValue();
-    }
-
-    if (ctx_.view().rules().enabled(featureTokenEscrow) && !isXRP(amount))
-    {
-        auto const xferRate = transferRate(ctx_.view(), amount);
-        if (xferRate != parityRate)
-            (*slep)[sfTransferRate] = xferRate.value;
-    }
-
-    ctx_.view().insert(slep);
-
-    // Add escrow to sender's owner directory
-    {
-        auto page = ctx_.view().dirInsert(
-            keylet::ownerDir(account_), escrowKeylet, describeOwnerDir(account_));
-        if (!page)
-            return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfOwnerNode] = *page;
-    }
-
-    // If it's not a self-send, add escrow to recipient's owner directory.
-    AccountID const dest = ctx_.tx[sfDestination];
-    if (dest != account_)
-    {
-        auto page =
-            ctx_.view().dirInsert(keylet::ownerDir(dest), escrowKeylet, describeOwnerDir(dest));
-        if (!page)
-            return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfDestinationNode] = *page;
-    }
-
-    // IOU escrow objects are added to the issuer's owner directory to help
-    // track the total locked balance. For MPT, this isn't necessary because the
-    // locked balance is already stored directly in the MPTokenIssuance object.
-    AccountID const issuer = amount.getIssuer();
-    if (!isXRP(amount) && issuer != account_ && issuer != dest && !amount.holds<MPTIssue>())
-    {
-        auto page =
-            ctx_.view().dirInsert(keylet::ownerDir(issuer), escrowKeylet, describeOwnerDir(issuer));
-        if (!page)
-            return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfIssuerNode] = *page;
-    }
-
-    // Deduct owner's balance
-    if (isXRP(amount))
-        (*sle)[sfBalance] = (*sle)[sfBalance] - amount;
-    else
-    {
-        if (auto const ret = std::visit(
-                [&]<typename T>(T const&) {
-                    return escrowLockApplyHelper<T>(ctx_.view(), issuer, account_, amount, j_);
-                },
-                amount.asset().value());
-            !isTesSuccess(ret))
-        {
-            return ret;  // LCOV_EXCL_LINE
-        }
-    }
-
-    // increment owner count
-    adjustOwnerCount(ctx_.view(), sle, 1, ctx_.journal);
-    ctx_.view().update(sle);
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/escrow/EscrowFinish.cpp

@@ -1,372 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/basics/chrono.h>
-#include <xrpl/conditions/Condition.h>
-#include <xrpl/conditions/Fulfillment.h>
-#include <xrpl/core/HashRouter.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/CredentialHelpers.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/TxFlags.h>
-#include <xrpl/protocol/XRPAmount.h>
-#include <xrpl/tx/transactors/escrow/EscrowFinish.h>
-
-#include <libxrpl/tx/transactors/escrow/EscrowHelpers.h>
-
-namespace xrpl {
-
-// During an EscrowFinish, the transaction must specify both
-// a condition and a fulfillment. We track whether that
-// fulfillment matches and validates the condition.
-constexpr HashRouterFlags SF_CF_INVALID = HashRouterFlags::PRIVATE5;
-constexpr HashRouterFlags SF_CF_VALID = HashRouterFlags::PRIVATE6;
-
-//------------------------------------------------------------------------------
-
-static bool
-checkCondition(Slice f, Slice c)
-{
-    using namespace xrpl::cryptoconditions;
-
-    std::error_code ec;
-
-    auto condition = Condition::deserialize(c, ec);
-    if (!condition)
-        return false;
-
-    auto fulfillment = Fulfillment::deserialize(f, ec);
-    if (!fulfillment)
-        return false;
-
-    return validate(*fulfillment, *condition);
-}
-
-bool
-EscrowFinish::checkExtraFeatures(PreflightContext const& ctx)
-{
-    return !ctx.tx.isFieldPresent(sfCredentialIDs) || ctx.rules.enabled(featureCredentials);
-}
-
-NotTEC
-EscrowFinish::preflight(PreflightContext const& ctx)
-{
-    auto const cb = ctx.tx[~sfCondition];
-    auto const fb = ctx.tx[~sfFulfillment];
-
-    // If you specify a condition, then you must also specify
-    // a fulfillment.
-    if (static_cast<bool>(cb) != static_cast<bool>(fb))
-        return temMALFORMED;
-
-    return tesSUCCESS;
-}
-
-NotTEC
-EscrowFinish::preflightSigValidated(PreflightContext const& ctx)
-{
-    auto const cb = ctx.tx[~sfCondition];
-    auto const fb = ctx.tx[~sfFulfillment];
-
-    if (cb && fb)
-    {
-        auto& router = ctx.registry.getHashRouter();
-
-        auto const id = ctx.tx.getTransactionID();
-        auto const flags = router.getFlags(id);
-
-        // If we haven't checked the condition, check it
-        // now. Whether it passes or not isn't important
-        // in preflight.
-        if (!any(flags & (SF_CF_INVALID | SF_CF_VALID)))
-        {
-            if (checkCondition(*fb, *cb))
-                router.setFlags(id, SF_CF_VALID);
-            else
-                router.setFlags(id, SF_CF_INVALID);
-        }
-    }
-
-    if (auto const err = credentials::checkFields(ctx.tx, ctx.j); !isTesSuccess(err))
-        return err;
-
-    return tesSUCCESS;
-}
-
-XRPAmount
-EscrowFinish::calculateBaseFee(ReadView const& view, STTx const& tx)
-{
-    XRPAmount extraFee{0};
-
-    if (auto const fb = tx[~sfFulfillment])
-    {
-        extraFee += view.fees().base * (32 + (fb->size() / 16));
-    }
-
-    return Transactor::calculateBaseFee(view, tx) + extraFee;
-}
-
-template <ValidIssueType T>
-static TER
-escrowFinishPreclaimHelper(
-    PreclaimContext const& ctx,
-    AccountID const& dest,
-    STAmount const& amount);
-
-template <>
-TER
-escrowFinishPreclaimHelper<Issue>(
-    PreclaimContext const& ctx,
-    AccountID const& dest,
-    STAmount const& amount)
-{
-    AccountID issuer = amount.getIssuer();
-    // If the issuer is the same as the account, return tesSUCCESS
-    if (issuer == dest)
-        return tesSUCCESS;
-
-    // If the issuer has requireAuth set, check if the destination is authorized
-    if (auto const ter = requireAuth(ctx.view, amount.issue(), dest); ter != tesSUCCESS)
-        return ter;
-
-    // If the issuer has deep frozen the destination, return tecFROZEN
-    if (isDeepFrozen(ctx.view, dest, amount.getCurrency(), amount.getIssuer()))
-        return tecFROZEN;
-
-    return tesSUCCESS;
-}
-
-template <>
-TER
-escrowFinishPreclaimHelper<MPTIssue>(
-    PreclaimContext const& ctx,
-    AccountID const& dest,
-    STAmount const& amount)
-{
-    AccountID issuer = amount.getIssuer();
-    // If the issuer is the same as the dest, return tesSUCCESS
-    if (issuer == dest)
-        return tesSUCCESS;
-
-    // If the mpt does not exist, return tecOBJECT_NOT_FOUND
-    auto const issuanceKey = keylet::mptIssuance(amount.get<MPTIssue>().getMptID());
-    auto const sleIssuance = ctx.view.read(issuanceKey);
-    if (!sleIssuance)
-        return tecOBJECT_NOT_FOUND;
-
-    // If the issuer has requireAuth set, check if the destination is
-    // authorized
-    auto const& mptIssue = amount.get<MPTIssue>();
-    if (auto const ter = requireAuth(ctx.view, mptIssue, dest, AuthType::WeakAuth);
-        ter != tesSUCCESS)
-        return ter;
-
-    // If the issuer has frozen the destination, return tecLOCKED
-    if (isFrozen(ctx.view, dest, mptIssue))
-        return tecLOCKED;
-
-    return tesSUCCESS;
-}
-
-TER
-EscrowFinish::preclaim(PreclaimContext const& ctx)
-{
-    if (ctx.view.rules().enabled(featureCredentials))
-    {
-        if (auto const err = credentials::valid(ctx.tx, ctx.view, ctx.tx[sfAccount], ctx.j);
-            !isTesSuccess(err))
-            return err;
-    }
-
-    if (ctx.view.rules().enabled(featureTokenEscrow))
-    {
-        auto const k = keylet::escrow(ctx.tx[sfOwner], ctx.tx[sfOfferSequence]);
-        auto const slep = ctx.view.read(k);
-        if (!slep)
-            return tecNO_TARGET;
-
-        AccountID const dest = (*slep)[sfDestination];
-        STAmount const amount = (*slep)[sfAmount];
-
-        if (!isXRP(amount))
-        {
-            if (auto const ret = std::visit(
-                    [&]<typename T>(T const&) {
-                        return escrowFinishPreclaimHelper<T>(ctx, dest, amount);
-                    },
-                    amount.asset().value());
-                !isTesSuccess(ret))
-                return ret;
-        }
-    }
-    return tesSUCCESS;
-}
-
-TER
-EscrowFinish::doApply()
-{
-    auto const k = keylet::escrow(ctx_.tx[sfOwner], ctx_.tx[sfOfferSequence]);
-    auto const slep = ctx_.view().peek(k);
-    if (!slep)
-    {
-        if (ctx_.view().rules().enabled(featureTokenEscrow))
-            return tecINTERNAL;  // LCOV_EXCL_LINE
-
-        return tecNO_TARGET;
-    }
-
-    // If a cancel time is present, a finish operation should only succeed prior
-    // to that time.
-    auto const now = ctx_.view().header().parentCloseTime;
-
-    // Too soon: can't execute before the finish time
-    if ((*slep)[~sfFinishAfter] && !after(now, (*slep)[sfFinishAfter]))
-        return tecNO_PERMISSION;
-
-    // Too late: can't execute after the cancel time
-    if ((*slep)[~sfCancelAfter] && after(now, (*slep)[sfCancelAfter]))
-        return tecNO_PERMISSION;
-
-    // Check cryptocondition fulfillment
-    {
-        auto const id = ctx_.tx.getTransactionID();
-        auto flags = ctx_.registry.getHashRouter().getFlags(id);
-
-        auto const cb = ctx_.tx[~sfCondition];
-
-        // It's unlikely that the results of the check will
-        // expire from the hash router, but if it happens,
-        // simply re-run the check.
-        if (cb && !any(flags & (SF_CF_INVALID | SF_CF_VALID)))
-        {
-            // LCOV_EXCL_START
-            auto const fb = ctx_.tx[~sfFulfillment];
-
-            if (!fb)
-                return tecINTERNAL;
-
-            if (checkCondition(*fb, *cb))
-                flags = SF_CF_VALID;
-            else
-                flags = SF_CF_INVALID;
-
-            ctx_.registry.getHashRouter().setFlags(id, flags);
-            // LCOV_EXCL_STOP
-        }
-
-        // If the check failed, then simply return an error
-        // and don't look at anything else.
-        if (any(flags & SF_CF_INVALID))
-            return tecCRYPTOCONDITION_ERROR;
-
-        // Check against condition in the ledger entry:
-        auto const cond = (*slep)[~sfCondition];
-
-        // If a condition wasn't specified during creation,
-        // one shouldn't be included now.
-        if (!cond && cb)
-            return tecCRYPTOCONDITION_ERROR;
-
-        // If a condition was specified during creation of
-        // the suspended payment, the identical condition
-        // must be presented again. We don't check if the
-        // fulfillment matches the condition since we did
-        // that in preflight.
-        if (cond && (cond != cb))
-            return tecCRYPTOCONDITION_ERROR;
-    }
-
-    // NOTE: Escrow payments cannot be used to fund accounts.
-    AccountID const destID = (*slep)[sfDestination];
-    auto const sled = ctx_.view().peek(keylet::account(destID));
-    if (!sled)
-        return tecNO_DST;
-
-    if (auto err = verifyDepositPreauth(ctx_.tx, ctx_.view(), account_, destID, sled, ctx_.journal);
-        !isTesSuccess(err))
-        return err;
-
-    AccountID const account = (*slep)[sfAccount];
-
-    // Remove escrow from owner directory
-    {
-        auto const page = (*slep)[sfOwnerNode];
-        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, k.key, true))
-        {
-            // LCOV_EXCL_START
-            JLOG(j_.fatal()) << "Unable to delete Escrow from owner.";
-            return tefBAD_LEDGER;
-            // LCOV_EXCL_STOP
-        }
-    }
-
-    // Remove escrow from recipient's owner directory, if present.
-    if (auto const optPage = (*slep)[~sfDestinationNode])
-    {
-        if (!ctx_.view().dirRemove(keylet::ownerDir(destID), *optPage, k.key, true))
-        {
-            // LCOV_EXCL_START
-            JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
-            return tefBAD_LEDGER;
-            // LCOV_EXCL_STOP
-        }
-    }
-
-    STAmount const amount = slep->getFieldAmount(sfAmount);
-    // Transfer amount to destination
-    if (isXRP(amount))
-        (*sled)[sfBalance] = (*sled)[sfBalance] + amount;
-    else
-    {
-        if (!ctx_.view().rules().enabled(featureTokenEscrow))
-            return temDISABLED;  // LCOV_EXCL_LINE
-
-        Rate lockedRate = slep->isFieldPresent(sfTransferRate)
-            ? xrpl::Rate(slep->getFieldU32(sfTransferRate))
-            : parityRate;
-        auto const issuer = amount.getIssuer();
-        bool const createAsset = destID == account_;
-        if (auto const ret = std::visit(
-                [&]<typename T>(T const&) {
-                    return escrowUnlockApplyHelper<T>(
-                        ctx_.view(),
-                        lockedRate,
-                        sled,
-                        mPriorBalance,
-                        amount,
-                        issuer,
-                        account,
-                        destID,
-                        createAsset,
-                        j_);
-                },
-                amount.asset().value());
-            !isTesSuccess(ret))
-            return ret;
-
-        // Remove escrow from issuers owner directory, if present.
-        if (auto const optPage = (*slep)[~sfIssuerNode]; optPage)
-        {
-            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, k.key, true))
-            {
-                // LCOV_EXCL_START
-                JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
-                return tefBAD_LEDGER;
-                // LCOV_EXCL_STOP
-            }
-        }
-    }
-
-    ctx_.view().update(sled);
-
-    // Adjust source owner count
-    auto const sle = ctx_.view().peek(keylet::account(account));
-    adjustOwnerCount(ctx_.view(), sle, -1, ctx_.journal);
-    ctx_.view().update(sle);
-
-    // Remove escrow from ledger
-    ctx_.view().erase(slep);
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/escrow/EscrowHelpers.h

@@ -1,229 +0,0 @@
-#pragma once
-
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/MPTAmount.h>
-#include <xrpl/tx/transactors/token/MPTokenAuthorize.h>
-
-namespace xrpl {
-
-template <ValidIssueType T>
-TER
-escrowUnlockApplyHelper(
-    ApplyView& view,
-    Rate lockedRate,
-    std::shared_ptr<SLE> const& sleDest,
-    STAmount const& xrpBalance,
-    STAmount const& amount,
-    AccountID const& issuer,
-    AccountID const& sender,
-    AccountID const& receiver,
-    bool createAsset,
-    beast::Journal journal);
-
-template <>
-inline TER
-escrowUnlockApplyHelper<Issue>(
-    ApplyView& view,
-    Rate lockedRate,
-    std::shared_ptr<SLE> const& sleDest,
-    STAmount const& xrpBalance,
-    STAmount const& amount,
-    AccountID const& issuer,
-    AccountID const& sender,
-    AccountID const& receiver,
-    bool createAsset,
-    beast::Journal journal)
-{
-    Keylet const trustLineKey = keylet::line(receiver, amount.issue());
-    bool const recvLow = issuer > receiver;
-    bool const senderIssuer = issuer == sender;
-    bool const receiverIssuer = issuer == receiver;
-    bool const issuerHigh = issuer > receiver;
-
-    if (senderIssuer)
-        return tecINTERNAL;  // LCOV_EXCL_LINE
-
-    if (receiverIssuer)
-        return tesSUCCESS;
-
-    if (!view.exists(trustLineKey) && createAsset && !receiverIssuer)
-    {
-        // Can the account cover the trust line's reserve?
-        if (std::uint32_t const ownerCount = {sleDest->at(sfOwnerCount)};
-            xrpBalance < view.fees().accountReserve(ownerCount + 1))
-        {
-            JLOG(journal.trace()) << "Trust line does not exist. "
-                                     "Insufficient reserve to create line.";
-
-            return tecNO_LINE_INSUF_RESERVE;
-        }
-
-        Currency const currency = amount.getCurrency();
-        STAmount initialBalance(amount.issue());
-        initialBalance.setIssuer(noAccount());
-
-        // clang-format off
-        if (TER const ter = trustCreate(
-                view,                           // payment sandbox
-                recvLow,                        // is dest low?
-                issuer,                         // source
-                receiver,                       // destination
-                trustLineKey.key,               // ledger index
-                sleDest,                        // Account to add to
-                false,                          // authorize account
-                (sleDest->getFlags() & lsfDefaultRipple) == 0,
-                false,                          // freeze trust line
-                false,                          // deep freeze trust line
-                initialBalance,                 // zero initial balance
-                Issue(currency, receiver),      // limit of zero
-                0,                              // quality in
-                0,                              // quality out
-                journal);                       // journal
-            !isTesSuccess(ter))
-        {
-            return ter; // LCOV_EXCL_LINE
-        }
-        // clang-format on
-
-        view.update(sleDest);
-    }
-
-    if (!view.exists(trustLineKey) && !receiverIssuer)
-        return tecNO_LINE;
-
-    auto const xferRate = transferRate(view, amount);
-    // update if issuer rate is less than locked rate
-    if (xferRate < lockedRate)
-        lockedRate = xferRate;
-
-    // Transfer Rate only applies when:
-    // 1. Issuer is not involved in the transfer (senderIssuer or
-    // receiverIssuer)
-    // 2. The locked rate is different from the parity rate
-
-    // NOTE: Transfer fee in escrow works a bit differently from a normal
-    // payment. In escrow, the fee is deducted from the locked/sending amount,
-    // whereas in a normal payment, the transfer fee is taken on top of the
-    // sending amount.
-    auto finalAmt = amount;
-    if ((!senderIssuer && !receiverIssuer) && lockedRate != parityRate)
-    {
-        // compute transfer fee, if any
-        auto const xferFee = amount.value() - divideRound(amount, lockedRate, amount.issue(), true);
-        // compute balance to transfer
-        finalAmt = amount.value() - xferFee;
-    }
-
-    // validate the line limit if the account submitting txn is not the receiver
-    // of the funds
-    if (!createAsset)
-    {
-        auto const sleRippleState = view.peek(trustLineKey);
-        if (!sleRippleState)
-            return tecINTERNAL;  // LCOV_EXCL_LINE
-
-        // if the issuer is the high, then we use the low limit
-        // otherwise we use the high limit
-        STAmount const lineLimit =
-            sleRippleState->getFieldAmount(issuerHigh ? sfLowLimit : sfHighLimit);
-
-        STAmount lineBalance = sleRippleState->getFieldAmount(sfBalance);
-
-        // flip the sign of the line balance if the issuer is not high
-        if (!issuerHigh)
-            lineBalance.negate();
-
-        // add the final amount to the line balance
-        lineBalance += finalAmt;
-
-        // if the transfer would exceed the line limit return tecLIMIT_EXCEEDED
-        if (lineLimit < lineBalance)
-            return tecLIMIT_EXCEEDED;
-    }
-
-    // if destination is not the issuer then transfer funds
-    if (!receiverIssuer)
-    {
-        auto const ter = rippleCredit(view, issuer, receiver, finalAmt, true, journal);
-        if (ter != tesSUCCESS)
-            return ter;  // LCOV_EXCL_LINE
-    }
-    return tesSUCCESS;
-}
-
-template <>
-inline TER
-escrowUnlockApplyHelper<MPTIssue>(
-    ApplyView& view,
-    Rate lockedRate,
-    std::shared_ptr<SLE> const& sleDest,
-    STAmount const& xrpBalance,
-    STAmount const& amount,
-    AccountID const& issuer,
-    AccountID const& sender,
-    AccountID const& receiver,
-    bool createAsset,
-    beast::Journal journal)
-{
-    bool const senderIssuer = issuer == sender;
-    bool const receiverIssuer = issuer == receiver;
-
-    auto const mptID = amount.get<MPTIssue>().getMptID();
-    auto const issuanceKey = keylet::mptIssuance(mptID);
-    if (!view.exists(keylet::mptoken(issuanceKey.key, receiver)) && createAsset && !receiverIssuer)
-    {
-        if (std::uint32_t const ownerCount = {sleDest->at(sfOwnerCount)};
-            xrpBalance < view.fees().accountReserve(ownerCount + 1))
-        {
-            return tecINSUFFICIENT_RESERVE;
-        }
-
-        if (auto const ter = MPTokenAuthorize::createMPToken(view, mptID, receiver, 0);
-            !isTesSuccess(ter))
-        {
-            return ter;  // LCOV_EXCL_LINE
-        }
-
-        // update owner count.
-        adjustOwnerCount(view, sleDest, 1, journal);
-    }
-
-    if (!view.exists(keylet::mptoken(issuanceKey.key, receiver)) && !receiverIssuer)
-        return tecNO_PERMISSION;
-
-    auto const xferRate = transferRate(view, amount);
-    // update if issuer rate is less than locked rate
-    if (xferRate < lockedRate)
-        lockedRate = xferRate;
-
-    // Transfer Rate only applies when:
-    // 1. Issuer is not involved in the transfer (senderIssuer or
-    // receiverIssuer)
-    // 2. The locked rate is different from the parity rate
-
-    // NOTE: Transfer fee in escrow works a bit differently from a normal
-    // payment. In escrow, the fee is deducted from the locked/sending amount,
-    // whereas in a normal payment, the transfer fee is taken on top of the
-    // sending amount.
-    auto finalAmt = amount;
-    if ((!senderIssuer && !receiverIssuer) && lockedRate != parityRate)
-    {
-        // compute transfer fee, if any
-        auto const xferFee = amount.value() - divideRound(amount, lockedRate, amount.asset(), true);
-        // compute balance to transfer
-        finalAmt = amount.value() - xferFee;
-    }
-    return rippleUnlockEscrowMPT(
-        view,
-        sender,
-        receiver,
-        finalAmt,
-        view.rules().enabled(fixTokenEscrowV1) ? amount : finalAmt,
-        journal);
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/payment_channel/PayChan.cpp

@@ -0,0 +1,542 @@
+#include <xrpl/basics/Log.h>
+#include <xrpl/basics/chrono.h>
+#include <xrpl/ledger/ApplyView.h>
+#include <xrpl/ledger/CredentialHelpers.h>
+#include <xrpl/ledger/View.h>
+#include <xrpl/protocol/Feature.h>
+#include <xrpl/protocol/Indexes.h>
+#include <xrpl/protocol/PayChan.h>
+#include <xrpl/protocol/PublicKey.h>
+#include <xrpl/protocol/TxFlags.h>
+#include <xrpl/protocol/XRPAmount.h>
+#include <xrpl/protocol/digest.h>
+#include <xrpl/tx/transactors/payment_channel/PayChan.h>
+
+namespace xrpl {
+
+/*
+    PaymentChannel
+
+        Payment channels permit off-ledger checkpoints of XRP payments flowing
+        in a single direction. A channel sequesters the owner's XRP in its own
+        ledger entry. The owner can authorize the recipient to claim up to a
+        given balance by giving the receiver a signed message (off-ledger). The
+        recipient can use this signed message to claim any unpaid balance while
+        the channel remains open. The owner can top off the line as needed. If
+        the channel has not paid out all its funds, the owner must wait out a
+        delay to close the channel to give the recipient a chance to supply any
+        claims. The recipient can close the channel at any time. Any transaction
+        that touches the channel after the expiration time will close the
+        channel. The total amount paid increases monotonically as newer claims
+        are issued. When the channel is closed any remaining balance is returned
+        to the owner. Channels are intended to permit intermittent off-ledger
+        settlement of ILP trust lines as balances get substantial. For
+        bidirectional channels, a payment channel can be used in each direction.
+
+    PaymentChannelCreate
+
+        Create a unidirectional channel. The parameters are:
+        Destination
+            The recipient at the end of the channel.
+        Amount
+            The amount of XRP to deposit in the channel immediately.
+        SettleDelay
+            The amount of time everyone but the recipient must wait for a
+            superior claim.
+        PublicKey
+            The key that will sign claims against the channel.
+        CancelAfter (optional)
+            Any channel transaction that touches this channel after the
+            `CancelAfter` time will close it.
+        DestinationTag (optional)
+            Destination tags allow the different accounts inside of a Hosted
+            Wallet to be mapped back onto the Ripple ledger. The destination tag
+            tells the server to which account in the Hosted Wallet the funds are
+            intended to go to. Required if the destination has lsfRequireDestTag
+            set.
+        SourceTag (optional)
+            Source tags allow the different accounts inside of a Hosted Wallet
+            to be mapped back onto the Ripple ledger. Source tags are similar to
+            destination tags but are for the channel owner to identify their own
+            transactions.
+
+    PaymentChannelFund
+
+        Add additional funds to the payment channel. Only the channel owner may
+        use this transaction. The parameters are:
+        Channel
+            The 256-bit ID of the channel.
+        Amount
+            The amount of XRP to add.
+        Expiration (optional)
+            Time the channel closes. The transaction will fail if the expiration
+            times does not satisfy the SettleDelay constraints.
+
+    PaymentChannelClaim
+
+        Place a claim against an existing channel. The parameters are:
+        Channel
+            The 256-bit ID of the channel.
+        Balance (optional)
+            The total amount of XRP delivered after this claim is processed
+   (optional, not needed if just closing). Amount (optional) The amount of XRP
+   the signature is for (not needed if equal to Balance or just closing the
+   line). Signature (optional) Authorization for the balance above, signed by
+   the owner (optional, not needed if closing or owner is performing the
+   transaction). The signature if for the following message: CLM\0 followed by
+   the 256-bit channel ID, and a 64-bit integer drops. PublicKey (optional) The
+   public key that made the signature (optional, required if a signature is
+   present) Flags tfClose Request that the channel be closed tfRenew Request
+   that the channel's expiration be reset. Only the owner may renew a channel.
+
+*/
+
+//------------------------------------------------------------------------------
+
+static TER
+closeChannel(
+    std::shared_ptr<SLE> const& slep,
+    ApplyView& view,
+    uint256 const& key,
+    beast::Journal j)
+{
+    AccountID const src = (*slep)[sfAccount];
+    // Remove PayChan from owner directory
+    {
+        auto const page = (*slep)[sfOwnerNode];
+        if (!view.dirRemove(keylet::ownerDir(src), page, key, true))
+        {
+            // LCOV_EXCL_START
+            JLOG(j.fatal()) << "Could not remove paychan from src owner directory";
+            return tefBAD_LEDGER;
+            // LCOV_EXCL_STOP
+        }
+    }
+
+    // Remove PayChan from recipient's owner directory, if present.
+    if (auto const page = (*slep)[~sfDestinationNode])
+    {
+        auto const dst = (*slep)[sfDestination];
+        if (!view.dirRemove(keylet::ownerDir(dst), *page, key, true))
+        {
+            // LCOV_EXCL_START
+            JLOG(j.fatal()) << "Could not remove paychan from dst owner directory";
+            return tefBAD_LEDGER;
+            // LCOV_EXCL_STOP
+        }
+    }
+
+    // Transfer amount back to owner, decrement owner count
+    auto const sle = view.peek(keylet::account(src));
+    if (!sle)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    XRPL_ASSERT(
+        (*slep)[sfAmount] >= (*slep)[sfBalance], "xrpl::closeChannel : minimum channel amount");
+    (*sle)[sfBalance] = (*sle)[sfBalance] + (*slep)[sfAmount] - (*slep)[sfBalance];
+    adjustOwnerCount(view, sle, -1, j);
+    view.update(sle);
+
+    // Remove PayChan from ledger
+    view.erase(slep);
+    return tesSUCCESS;
+}
+
+//------------------------------------------------------------------------------
+
+TxConsequences
+PayChanCreate::makeTxConsequences(PreflightContext const& ctx)
+{
+    return TxConsequences{ctx.tx, ctx.tx[sfAmount].xrp()};
+}
+
+NotTEC
+PayChanCreate::preflight(PreflightContext const& ctx)
+{
+    if (!isXRP(ctx.tx[sfAmount]) || (ctx.tx[sfAmount] <= beast::zero))
+        return temBAD_AMOUNT;
+
+    if (ctx.tx[sfAccount] == ctx.tx[sfDestination])
+        return temDST_IS_SRC;
+
+    if (!publicKeyType(ctx.tx[sfPublicKey]))
+        return temMALFORMED;
+
+    return tesSUCCESS;
+}
+
+TER
+PayChanCreate::preclaim(PreclaimContext const& ctx)
+{
+    auto const account = ctx.tx[sfAccount];
+    auto const sle = ctx.view.read(keylet::account(account));
+    if (!sle)
+        return terNO_ACCOUNT;
+
+    // Check reserve and funds availability
+    {
+        auto const balance = (*sle)[sfBalance];
+        auto const reserve = ctx.view.fees().accountReserve((*sle)[sfOwnerCount] + 1);
+
+        if (balance < reserve)
+            return tecINSUFFICIENT_RESERVE;
+
+        if (balance < reserve + ctx.tx[sfAmount])
+            return tecUNFUNDED;
+    }
+
+    auto const dst = ctx.tx[sfDestination];
+
+    {
+        // Check destination account
+        auto const sled = ctx.view.read(keylet::account(dst));
+        if (!sled)
+            return tecNO_DST;
+
+        auto const flags = sled->getFlags();
+
+        // Check if they have disallowed incoming payment channels
+        if (flags & lsfDisallowIncomingPayChan)
+            return tecNO_PERMISSION;
+
+        if ((flags & lsfRequireDestTag) && !ctx.tx[~sfDestinationTag])
+            return tecDST_TAG_NEEDED;
+
+        // Pseudo-accounts cannot receive payment channels, other than native
+        // to their underlying ledger object - implemented in their respective
+        // transaction types. Note, this is not amendment-gated because all
+        // writes to pseudo-account discriminator fields **are** amendment
+        // gated, hence the behaviour of this check will always match the
+        // currently active amendments.
+        if (isPseudoAccount(sled))
+            return tecNO_PERMISSION;
+    }
+
+    return tesSUCCESS;
+}
+
+TER
+PayChanCreate::doApply()
+{
+    auto const account = ctx_.tx[sfAccount];
+    auto const sle = ctx_.view().peek(keylet::account(account));
+    if (!sle)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    if (ctx_.view().rules().enabled(fixPayChanCancelAfter))
+    {
+        auto const closeTime = ctx_.view().header().parentCloseTime;
+        if (ctx_.tx[~sfCancelAfter] && after(closeTime, ctx_.tx[sfCancelAfter]))
+            return tecEXPIRED;
+    }
+
+    auto const dst = ctx_.tx[sfDestination];
+
+    // Create PayChan in ledger.
+    //
+    // Note that we we use the value from the sequence or ticket as the
+    // payChan sequence.  For more explanation see comments in SeqProxy.h.
+    Keylet const payChanKeylet = keylet::payChan(account, dst, ctx_.tx.getSeqValue());
+    auto const slep = std::make_shared<SLE>(payChanKeylet);
+
+    // Funds held in this channel
+    (*slep)[sfAmount] = ctx_.tx[sfAmount];
+    // Amount channel has already paid
+    (*slep)[sfBalance] = ctx_.tx[sfAmount].zeroed();
+    (*slep)[sfAccount] = account;
+    (*slep)[sfDestination] = dst;
+    (*slep)[sfSettleDelay] = ctx_.tx[sfSettleDelay];
+    (*slep)[sfPublicKey] = ctx_.tx[sfPublicKey];
+    (*slep)[~sfCancelAfter] = ctx_.tx[~sfCancelAfter];
+    (*slep)[~sfSourceTag] = ctx_.tx[~sfSourceTag];
+    (*slep)[~sfDestinationTag] = ctx_.tx[~sfDestinationTag];
+    if (ctx_.view().rules().enabled(fixIncludeKeyletFields))
+    {
+        (*slep)[sfSequence] = ctx_.tx.getSeqValue();
+    }
+
+    ctx_.view().insert(slep);
+
+    // Add PayChan to owner directory
+    {
+        auto const page = ctx_.view().dirInsert(
+            keylet::ownerDir(account), payChanKeylet, describeOwnerDir(account));
+        if (!page)
+            return tecDIR_FULL;  // LCOV_EXCL_LINE
+        (*slep)[sfOwnerNode] = *page;
+    }
+
+    // Add PayChan to the recipient's owner directory
+    {
+        auto const page =
+            ctx_.view().dirInsert(keylet::ownerDir(dst), payChanKeylet, describeOwnerDir(dst));
+        if (!page)
+            return tecDIR_FULL;  // LCOV_EXCL_LINE
+        (*slep)[sfDestinationNode] = *page;
+    }
+
+    // Deduct owner's balance, increment owner count
+    (*sle)[sfBalance] = (*sle)[sfBalance] - ctx_.tx[sfAmount];
+    adjustOwnerCount(ctx_.view(), sle, 1, ctx_.journal);
+    ctx_.view().update(sle);
+
+    return tesSUCCESS;
+}
+
+//------------------------------------------------------------------------------
+
+TxConsequences
+PayChanFund::makeTxConsequences(PreflightContext const& ctx)
+{
+    return TxConsequences{ctx.tx, ctx.tx[sfAmount].xrp()};
+}
+
+NotTEC
+PayChanFund::preflight(PreflightContext const& ctx)
+{
+    if (!isXRP(ctx.tx[sfAmount]) || (ctx.tx[sfAmount] <= beast::zero))
+        return temBAD_AMOUNT;
+
+    return tesSUCCESS;
+}
+
+TER
+PayChanFund::doApply()
+{
+    Keylet const k(ltPAYCHAN, ctx_.tx[sfChannel]);
+    auto const slep = ctx_.view().peek(k);
+    if (!slep)
+        return tecNO_ENTRY;
+
+    AccountID const src = (*slep)[sfAccount];
+    auto const txAccount = ctx_.tx[sfAccount];
+    auto const expiration = (*slep)[~sfExpiration];
+
+    {
+        auto const cancelAfter = (*slep)[~sfCancelAfter];
+        auto const closeTime = ctx_.view().header().parentCloseTime.time_since_epoch().count();
+        if ((cancelAfter && closeTime >= *cancelAfter) || (expiration && closeTime >= *expiration))
+            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.journal("View"));
+    }
+
+    if (src != txAccount)
+        // only the owner can add funds or extend
+        return tecNO_PERMISSION;
+
+    if (auto extend = ctx_.tx[~sfExpiration])
+    {
+        auto minExpiration = ctx_.view().header().parentCloseTime.time_since_epoch().count() +
+            (*slep)[sfSettleDelay];
+        if (expiration && *expiration < minExpiration)
+            minExpiration = *expiration;
+
+        if (*extend < minExpiration)
+            return temBAD_EXPIRATION;
+        (*slep)[~sfExpiration] = *extend;
+        ctx_.view().update(slep);
+    }
+
+    auto const sle = ctx_.view().peek(keylet::account(txAccount));
+    if (!sle)
+        return tefINTERNAL;  // LCOV_EXCL_LINE
+
+    {
+        // Check reserve and funds availability
+        auto const balance = (*sle)[sfBalance];
+        auto const reserve = ctx_.view().fees().accountReserve((*sle)[sfOwnerCount]);
+
+        if (balance < reserve)
+            return tecINSUFFICIENT_RESERVE;
+
+        if (balance < reserve + ctx_.tx[sfAmount])
+            return tecUNFUNDED;
+    }
+
+    // do not allow adding funds if dst does not exist
+    if (AccountID const dst = (*slep)[sfDestination]; !ctx_.view().read(keylet::account(dst)))
+    {
+        return tecNO_DST;
+    }
+
+    (*slep)[sfAmount] = (*slep)[sfAmount] + ctx_.tx[sfAmount];
+    ctx_.view().update(slep);
+
+    (*sle)[sfBalance] = (*sle)[sfBalance] - ctx_.tx[sfAmount];
+    ctx_.view().update(sle);
+
+    return tesSUCCESS;
+}
+
+//------------------------------------------------------------------------------
+
+bool
+PayChanClaim::checkExtraFeatures(PreflightContext const& ctx)
+{
+    return !ctx.tx.isFieldPresent(sfCredentialIDs) || ctx.rules.enabled(featureCredentials);
+}
+
+std::uint32_t
+PayChanClaim::getFlagsMask(PreflightContext const&)
+{
+    return tfPaymentChannelClaimMask;
+}
+
+NotTEC
+PayChanClaim::preflight(PreflightContext const& ctx)
+{
+    auto const bal = ctx.tx[~sfBalance];
+    if (bal && (!isXRP(*bal) || *bal <= beast::zero))
+        return temBAD_AMOUNT;
+
+    auto const amt = ctx.tx[~sfAmount];
+    if (amt && (!isXRP(*amt) || *amt <= beast::zero))
+        return temBAD_AMOUNT;
+
+    if (bal && amt && *bal > *amt)
+        return temBAD_AMOUNT;
+
+    {
+        auto const flags = ctx.tx.getFlags();
+
+        if ((flags & tfClose) && (flags & tfRenew))
+            return temMALFORMED;
+    }
+
+    if (auto const sig = ctx.tx[~sfSignature])
+    {
+        if (!(ctx.tx[~sfPublicKey] && bal))
+            return temMALFORMED;
+
+        // Check the signature
+        // The signature isn't needed if txAccount == src, but if it's
+        // present, check it
+
+        auto const reqBalance = bal->xrp();
+        auto const authAmt = amt ? amt->xrp() : reqBalance;
+
+        if (reqBalance > authAmt)
+            return temBAD_AMOUNT;
+
+        Keylet const k(ltPAYCHAN, ctx.tx[sfChannel]);
+        if (!publicKeyType(ctx.tx[sfPublicKey]))
+            return temMALFORMED;
+
+        PublicKey const pk(ctx.tx[sfPublicKey]);
+        Serializer msg;
+        serializePayChanAuthorization(msg, k.key, authAmt);
+        if (!verify(pk, msg.slice(), *sig))
+            return temBAD_SIGNATURE;
+    }
+
+    if (auto const err = credentials::checkFields(ctx.tx, ctx.j); !isTesSuccess(err))
+        return err;
+
+    return tesSUCCESS;
+}
+
+TER
+PayChanClaim::preclaim(PreclaimContext const& ctx)
+{
+    if (!ctx.view.rules().enabled(featureCredentials))
+        return Transactor::preclaim(ctx);
+
+    if (auto const err = credentials::valid(ctx.tx, ctx.view, ctx.tx[sfAccount], ctx.j);
+        !isTesSuccess(err))
+        return err;
+
+    return tesSUCCESS;
+}
+
+TER
+PayChanClaim::doApply()
+{
+    Keylet const k(ltPAYCHAN, ctx_.tx[sfChannel]);
+    auto const slep = ctx_.view().peek(k);
+    if (!slep)
+        return tecNO_TARGET;
+
+    AccountID const src = (*slep)[sfAccount];
+    AccountID const dst = (*slep)[sfDestination];
+    AccountID const txAccount = ctx_.tx[sfAccount];
+
+    auto const curExpiration = (*slep)[~sfExpiration];
+    {
+        auto const cancelAfter = (*slep)[~sfCancelAfter];
+        auto const closeTime = ctx_.view().header().parentCloseTime.time_since_epoch().count();
+        if ((cancelAfter && closeTime >= *cancelAfter) ||
+            (curExpiration && closeTime >= *curExpiration))
+            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.journal("View"));
+    }
+
+    if (txAccount != src && txAccount != dst)
+        return tecNO_PERMISSION;
+
+    if (ctx_.tx[~sfBalance])
+    {
+        auto const chanBalance = slep->getFieldAmount(sfBalance).xrp();
+        auto const chanFunds = slep->getFieldAmount(sfAmount).xrp();
+        auto const reqBalance = ctx_.tx[sfBalance].xrp();
+
+        if (txAccount == dst && !ctx_.tx[~sfSignature])
+            return temBAD_SIGNATURE;
+
+        if (ctx_.tx[~sfSignature])
+        {
+            PublicKey const pk((*slep)[sfPublicKey]);
+            if (ctx_.tx[sfPublicKey] != pk)
+                return temBAD_SIGNER;
+        }
+
+        if (reqBalance > chanFunds)
+            return tecUNFUNDED_PAYMENT;
+
+        if (reqBalance <= chanBalance)
+            // nothing requested
+            return tecUNFUNDED_PAYMENT;
+
+        auto const sled = ctx_.view().peek(keylet::account(dst));
+        if (!sled)
+            return tecNO_DST;
+
+        if (auto err =
+                verifyDepositPreauth(ctx_.tx, ctx_.view(), txAccount, dst, sled, ctx_.journal);
+            !isTesSuccess(err))
+            return err;
+
+        (*slep)[sfBalance] = ctx_.tx[sfBalance];
+        XRPAmount const reqDelta = reqBalance - chanBalance;
+        XRPL_ASSERT(reqDelta >= beast::zero, "xrpl::PayChanClaim::doApply : minimum balance delta");
+        (*sled)[sfBalance] = (*sled)[sfBalance] + reqDelta;
+        ctx_.view().update(sled);
+        ctx_.view().update(slep);
+    }
+
+    if (ctx_.tx.getFlags() & tfRenew)
+    {
+        if (src != txAccount)
+            return tecNO_PERMISSION;
+        (*slep)[~sfExpiration] = std::nullopt;
+        ctx_.view().update(slep);
+    }
+
+    if (ctx_.tx.getFlags() & tfClose)
+    {
+        // Channel will close immediately if dry or the receiver closes
+        if (dst == txAccount || (*slep)[sfBalance] == (*slep)[sfAmount])
+            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.journal("View"));
+
+        auto const settleExpiration =
+            ctx_.view().header().parentCloseTime.time_since_epoch().count() +
+            (*slep)[sfSettleDelay];
+
+        if (!curExpiration || *curExpiration > settleExpiration)
+        {
+            (*slep)[~sfExpiration] = settleExpiration;
+            ctx_.view().update(slep);
+        }
+    }
+
+    return tesSUCCESS;
+}
+
+}  // namespace xrpl

src/libxrpl/tx/transactors/payment_channel/PayChanClaim.cpp

@@ -1,186 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/CredentialHelpers.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/PayChan.h>
-#include <xrpl/protocol/PublicKey.h>
-#include <xrpl/protocol/TxFlags.h>
-#include <xrpl/tx/transactors/payment_channel/PayChanClaim.h>
-
-#include <libxrpl/tx/transactors/payment_channel/PayChanHelpers.h>
-
-namespace xrpl {
-
-bool
-PayChanClaim::checkExtraFeatures(PreflightContext const& ctx)
-{
-    return !ctx.tx.isFieldPresent(sfCredentialIDs) || ctx.rules.enabled(featureCredentials);
-}
-
-std::uint32_t
-PayChanClaim::getFlagsMask(PreflightContext const&)
-{
-    return tfPaymentChannelClaimMask;
-}
-
-NotTEC
-PayChanClaim::preflight(PreflightContext const& ctx)
-{
-    auto const bal = ctx.tx[~sfBalance];
-    if (bal && (!isXRP(*bal) || *bal <= beast::zero))
-        return temBAD_AMOUNT;
-
-    auto const amt = ctx.tx[~sfAmount];
-    if (amt && (!isXRP(*amt) || *amt <= beast::zero))
-        return temBAD_AMOUNT;
-
-    if (bal && amt && *bal > *amt)
-        return temBAD_AMOUNT;
-
-    {
-        auto const flags = ctx.tx.getFlags();
-
-        if ((flags & tfClose) && (flags & tfRenew))
-            return temMALFORMED;
-    }
-
-    if (auto const sig = ctx.tx[~sfSignature])
-    {
-        if (!(ctx.tx[~sfPublicKey] && bal))
-            return temMALFORMED;
-
-        // Check the signature
-        // The signature isn't needed if txAccount == src, but if it's
-        // present, check it
-
-        auto const reqBalance = bal->xrp();
-        auto const authAmt = amt ? amt->xrp() : reqBalance;
-
-        if (reqBalance > authAmt)
-            return temBAD_AMOUNT;
-
-        Keylet const k(ltPAYCHAN, ctx.tx[sfChannel]);
-        if (!publicKeyType(ctx.tx[sfPublicKey]))
-            return temMALFORMED;
-
-        PublicKey const pk(ctx.tx[sfPublicKey]);
-        Serializer msg;
-        serializePayChanAuthorization(msg, k.key, authAmt);
-        if (!verify(pk, msg.slice(), *sig))
-            return temBAD_SIGNATURE;
-    }
-
-    if (auto const err = credentials::checkFields(ctx.tx, ctx.j); !isTesSuccess(err))
-        return err;
-
-    return tesSUCCESS;
-}
-
-TER
-PayChanClaim::preclaim(PreclaimContext const& ctx)
-{
-    if (!ctx.view.rules().enabled(featureCredentials))
-        return Transactor::preclaim(ctx);
-
-    if (auto const err = credentials::valid(ctx.tx, ctx.view, ctx.tx[sfAccount], ctx.j);
-        !isTesSuccess(err))
-        return err;
-
-    return tesSUCCESS;
-}
-
-TER
-PayChanClaim::doApply()
-{
-    Keylet const k(ltPAYCHAN, ctx_.tx[sfChannel]);
-    auto const slep = ctx_.view().peek(k);
-    if (!slep)
-        return tecNO_TARGET;
-
-    AccountID const src = (*slep)[sfAccount];
-    AccountID const dst = (*slep)[sfDestination];
-    AccountID const txAccount = ctx_.tx[sfAccount];
-
-    auto const curExpiration = (*slep)[~sfExpiration];
-    {
-        auto const cancelAfter = (*slep)[~sfCancelAfter];
-        auto const closeTime = ctx_.view().header().parentCloseTime.time_since_epoch().count();
-        if ((cancelAfter && closeTime >= *cancelAfter) ||
-            (curExpiration && closeTime >= *curExpiration))
-            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.journal("View"));
-    }
-
-    if (txAccount != src && txAccount != dst)
-        return tecNO_PERMISSION;
-
-    if (ctx_.tx[~sfBalance])
-    {
-        auto const chanBalance = slep->getFieldAmount(sfBalance).xrp();
-        auto const chanFunds = slep->getFieldAmount(sfAmount).xrp();
-        auto const reqBalance = ctx_.tx[sfBalance].xrp();
-
-        if (txAccount == dst && !ctx_.tx[~sfSignature])
-            return temBAD_SIGNATURE;
-
-        if (ctx_.tx[~sfSignature])
-        {
-            PublicKey const pk((*slep)[sfPublicKey]);
-            if (ctx_.tx[sfPublicKey] != pk)
-                return temBAD_SIGNER;
-        }
-
-        if (reqBalance > chanFunds)
-            return tecUNFUNDED_PAYMENT;
-
-        if (reqBalance <= chanBalance)
-            // nothing requested
-            return tecUNFUNDED_PAYMENT;
-
-        auto const sled = ctx_.view().peek(keylet::account(dst));
-        if (!sled)
-            return tecNO_DST;
-
-        if (auto err =
-                verifyDepositPreauth(ctx_.tx, ctx_.view(), txAccount, dst, sled, ctx_.journal);
-            !isTesSuccess(err))
-            return err;
-
-        (*slep)[sfBalance] = ctx_.tx[sfBalance];
-        XRPAmount const reqDelta = reqBalance - chanBalance;
-        XRPL_ASSERT(reqDelta >= beast::zero, "xrpl::PayChanClaim::doApply : minimum balance delta");
-        (*sled)[sfBalance] = (*sled)[sfBalance] + reqDelta;
-        ctx_.view().update(sled);
-        ctx_.view().update(slep);
-    }
-
-    if (ctx_.tx.getFlags() & tfRenew)
-    {
-        if (src != txAccount)
-            return tecNO_PERMISSION;
-        (*slep)[~sfExpiration] = std::nullopt;
-        ctx_.view().update(slep);
-    }
-
-    if (ctx_.tx.getFlags() & tfClose)
-    {
-        // Channel will close immediately if dry or the receiver closes
-        if (dst == txAccount || (*slep)[sfBalance] == (*slep)[sfAmount])
-            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.journal("View"));
-
-        auto const settleExpiration =
-            ctx_.view().header().parentCloseTime.time_since_epoch().count() +
-            (*slep)[sfSettleDelay];
-
-        if (!curExpiration || *curExpiration > settleExpiration)
-        {
-            (*slep)[~sfExpiration] = settleExpiration;
-            ctx_.view().update(slep);
-        }
-    }
-
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/payment_channel/PayChanCreate.cpp

@@ -1,173 +0,0 @@
-#include <xrpl/basics/chrono.h>
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/protocol/PublicKey.h>
-#include <xrpl/protocol/XRPAmount.h>
-#include <xrpl/tx/transactors/payment_channel/PayChanCreate.h>
-
-namespace xrpl {
-
-/*
-    PaymentChannel
-
-        Payment channels permit off-ledger checkpoints of XRP payments flowing
-        in a single direction. A channel sequesters the owner's XRP in its own
-        ledger entry. The owner can authorize the recipient to claim up to a
-        given balance by giving the receiver a signed message (off-ledger). The
-        recipient can use this signed message to claim any unpaid balance while
-        the channel remains open. The owner can top off the line as needed. If
-        the channel has not paid out all its funds, the owner must wait out a
-        delay to close the channel to give the recipient a chance to supply any
-        claims. The recipient can close the channel at any time. Any transaction
-        that touches the channel after the expiration time will close the
-        channel. The total amount paid increases monotonically as newer claims
-        are issued. When the channel is closed any remaining balance is returned
-        to the owner. Channels are intended to permit intermittent off-ledger
-        settlement of ILP trust lines as balances get substantial. For
-        bidirectional channels, a payment channel can be used in each direction.
-*/
-
-//------------------------------------------------------------------------------
-
-TxConsequences
-PayChanCreate::makeTxConsequences(PreflightContext const& ctx)
-{
-    return TxConsequences{ctx.tx, ctx.tx[sfAmount].xrp()};
-}
-
-NotTEC
-PayChanCreate::preflight(PreflightContext const& ctx)
-{
-    if (!isXRP(ctx.tx[sfAmount]) || (ctx.tx[sfAmount] <= beast::zero))
-        return temBAD_AMOUNT;
-
-    if (ctx.tx[sfAccount] == ctx.tx[sfDestination])
-        return temDST_IS_SRC;
-
-    if (!publicKeyType(ctx.tx[sfPublicKey]))
-        return temMALFORMED;
-
-    return tesSUCCESS;
-}
-
-TER
-PayChanCreate::preclaim(PreclaimContext const& ctx)
-{
-    auto const account = ctx.tx[sfAccount];
-    auto const sle = ctx.view.read(keylet::account(account));
-    if (!sle)
-        return terNO_ACCOUNT;
-
-    // Check reserve and funds availability
-    {
-        auto const balance = (*sle)[sfBalance];
-        auto const reserve = ctx.view.fees().accountReserve((*sle)[sfOwnerCount] + 1);
-
-        if (balance < reserve)
-            return tecINSUFFICIENT_RESERVE;
-
-        if (balance < reserve + ctx.tx[sfAmount])
-            return tecUNFUNDED;
-    }
-
-    auto const dst = ctx.tx[sfDestination];
-
-    {
-        // Check destination account
-        auto const sled = ctx.view.read(keylet::account(dst));
-        if (!sled)
-            return tecNO_DST;
-
-        auto const flags = sled->getFlags();
-
-        // Check if they have disallowed incoming payment channels
-        if (flags & lsfDisallowIncomingPayChan)
-            return tecNO_PERMISSION;
-
-        if ((flags & lsfRequireDestTag) && !ctx.tx[~sfDestinationTag])
-            return tecDST_TAG_NEEDED;
-
-        // Pseudo-accounts cannot receive payment channels, other than native
-        // to their underlying ledger object - implemented in their respective
-        // transaction types. Note, this is not amendment-gated because all
-        // writes to pseudo-account discriminator fields **are** amendment
-        // gated, hence the behaviour of this check will always match the
-        // currently active amendments.
-        if (isPseudoAccount(sled))
-            return tecNO_PERMISSION;
-    }
-
-    return tesSUCCESS;
-}
-
-TER
-PayChanCreate::doApply()
-{
-    auto const account = ctx_.tx[sfAccount];
-    auto const sle = ctx_.view().peek(keylet::account(account));
-    if (!sle)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    if (ctx_.view().rules().enabled(fixPayChanCancelAfter))
-    {
-        auto const closeTime = ctx_.view().header().parentCloseTime;
-        if (ctx_.tx[~sfCancelAfter] && after(closeTime, ctx_.tx[sfCancelAfter]))
-            return tecEXPIRED;
-    }
-
-    auto const dst = ctx_.tx[sfDestination];
-
-    // Create PayChan in ledger.
-    //
-    // Note that we we use the value from the sequence or ticket as the
-    // payChan sequence.  For more explanation see comments in SeqProxy.h.
-    Keylet const payChanKeylet = keylet::payChan(account, dst, ctx_.tx.getSeqValue());
-    auto const slep = std::make_shared<SLE>(payChanKeylet);
-
-    // Funds held in this channel
-    (*slep)[sfAmount] = ctx_.tx[sfAmount];
-    // Amount channel has already paid
-    (*slep)[sfBalance] = ctx_.tx[sfAmount].zeroed();
-    (*slep)[sfAccount] = account;
-    (*slep)[sfDestination] = dst;
-    (*slep)[sfSettleDelay] = ctx_.tx[sfSettleDelay];
-    (*slep)[sfPublicKey] = ctx_.tx[sfPublicKey];
-    (*slep)[~sfCancelAfter] = ctx_.tx[~sfCancelAfter];
-    (*slep)[~sfSourceTag] = ctx_.tx[~sfSourceTag];
-    (*slep)[~sfDestinationTag] = ctx_.tx[~sfDestinationTag];
-    if (ctx_.view().rules().enabled(fixIncludeKeyletFields))
-    {
-        (*slep)[sfSequence] = ctx_.tx.getSeqValue();
-    }
-
-    ctx_.view().insert(slep);
-
-    // Add PayChan to owner directory
-    {
-        auto const page = ctx_.view().dirInsert(
-            keylet::ownerDir(account), payChanKeylet, describeOwnerDir(account));
-        if (!page)
-            return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfOwnerNode] = *page;
-    }
-
-    // Add PayChan to the recipient's owner directory
-    {
-        auto const page =
-            ctx_.view().dirInsert(keylet::ownerDir(dst), payChanKeylet, describeOwnerDir(dst));
-        if (!page)
-            return tecDIR_FULL;  // LCOV_EXCL_LINE
-        (*slep)[sfDestinationNode] = *page;
-    }
-
-    // Deduct owner's balance, increment owner count
-    (*sle)[sfBalance] = (*sle)[sfBalance] - ctx_.tx[sfAmount];
-    adjustOwnerCount(ctx_.view(), sle, 1, ctx_.journal);
-    ctx_.view().update(sle);
-
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/payment_channel/PayChanFund.cpp

@@ -1,92 +0,0 @@
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Indexes.h>
-#include <xrpl/tx/transactors/payment_channel/PayChanFund.h>
-
-#include <libxrpl/tx/transactors/payment_channel/PayChanHelpers.h>
-
-namespace xrpl {
-
-TxConsequences
-PayChanFund::makeTxConsequences(PreflightContext const& ctx)
-{
-    return TxConsequences{ctx.tx, ctx.tx[sfAmount].xrp()};
-}
-
-NotTEC
-PayChanFund::preflight(PreflightContext const& ctx)
-{
-    if (!isXRP(ctx.tx[sfAmount]) || (ctx.tx[sfAmount] <= beast::zero))
-        return temBAD_AMOUNT;
-
-    return tesSUCCESS;
-}
-
-TER
-PayChanFund::doApply()
-{
-    Keylet const k(ltPAYCHAN, ctx_.tx[sfChannel]);
-    auto const slep = ctx_.view().peek(k);
-    if (!slep)
-        return tecNO_ENTRY;
-
-    AccountID const src = (*slep)[sfAccount];
-    auto const txAccount = ctx_.tx[sfAccount];
-    auto const expiration = (*slep)[~sfExpiration];
-
-    {
-        auto const cancelAfter = (*slep)[~sfCancelAfter];
-        auto const closeTime = ctx_.view().header().parentCloseTime.time_since_epoch().count();
-        if ((cancelAfter && closeTime >= *cancelAfter) || (expiration && closeTime >= *expiration))
-            return closeChannel(slep, ctx_.view(), k.key, ctx_.registry.journal("View"));
-    }
-
-    if (src != txAccount)
-        // only the owner can add funds or extend
-        return tecNO_PERMISSION;
-
-    if (auto extend = ctx_.tx[~sfExpiration])
-    {
-        auto minExpiration = ctx_.view().header().parentCloseTime.time_since_epoch().count() +
-            (*slep)[sfSettleDelay];
-        if (expiration && *expiration < minExpiration)
-            minExpiration = *expiration;
-
-        if (*extend < minExpiration)
-            return temBAD_EXPIRATION;
-        (*slep)[~sfExpiration] = *extend;
-        ctx_.view().update(slep);
-    }
-
-    auto const sle = ctx_.view().peek(keylet::account(txAccount));
-    if (!sle)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    {
-        // Check reserve and funds availability
-        auto const balance = (*sle)[sfBalance];
-        auto const reserve = ctx_.view().fees().accountReserve((*sle)[sfOwnerCount]);
-
-        if (balance < reserve)
-            return tecINSUFFICIENT_RESERVE;
-
-        if (balance < reserve + ctx_.tx[sfAmount])
-            return tecUNFUNDED;
-    }
-
-    // do not allow adding funds if dst does not exist
-    if (AccountID const dst = (*slep)[sfDestination]; !ctx_.view().read(keylet::account(dst)))
-    {
-        return tecNO_DST;
-    }
-
-    (*slep)[sfAmount] = (*slep)[sfAmount] + ctx_.tx[sfAmount];
-    ctx_.view().update(slep);
-
-    (*sle)[sfBalance] = (*sle)[sfBalance] - ctx_.tx[sfAmount];
-    ctx_.view().update(sle);
-
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/payment_channel/PayChanHelpers.cpp

@@ -1,58 +0,0 @@
-#include <xrpl/basics/Log.h>
-#include <xrpl/ledger/View.h>
-#include <xrpl/protocol/Indexes.h>
-
-#include <libxrpl/tx/transactors/payment_channel/PayChanHelpers.h>
-
-namespace xrpl {
-
-TER
-closeChannel(
-    std::shared_ptr<SLE> const& slep,
-    ApplyView& view,
-    uint256 const& key,
-    beast::Journal j)
-{
-    AccountID const src = (*slep)[sfAccount];
-    // Remove PayChan from owner directory
-    {
-        auto const page = (*slep)[sfOwnerNode];
-        if (!view.dirRemove(keylet::ownerDir(src), page, key, true))
-        {
-            // LCOV_EXCL_START
-            JLOG(j.fatal()) << "Could not remove paychan from src owner directory";
-            return tefBAD_LEDGER;
-            // LCOV_EXCL_STOP
-        }
-    }
-
-    // Remove PayChan from recipient's owner directory, if present.
-    if (auto const page = (*slep)[~sfDestinationNode])
-    {
-        auto const dst = (*slep)[sfDestination];
-        if (!view.dirRemove(keylet::ownerDir(dst), *page, key, true))
-        {
-            // LCOV_EXCL_START
-            JLOG(j.fatal()) << "Could not remove paychan from dst owner directory";
-            return tefBAD_LEDGER;
-            // LCOV_EXCL_STOP
-        }
-    }
-
-    // Transfer amount back to owner, decrement owner count
-    auto const sle = view.peek(keylet::account(src));
-    if (!sle)
-        return tefINTERNAL;  // LCOV_EXCL_LINE
-
-    XRPL_ASSERT(
-        (*slep)[sfAmount] >= (*slep)[sfBalance], "xrpl::closeChannel : minimum channel amount");
-    (*sle)[sfBalance] = (*sle)[sfBalance] + (*slep)[sfAmount] - (*slep)[sfBalance];
-    adjustOwnerCount(view, sle, -1, j);
-    view.update(sle);
-
-    // Remove PayChan from ledger
-    view.erase(slep);
-    return tesSUCCESS;
-}
-
-}  // namespace xrpl

src/libxrpl/tx/transactors/payment_channel/PayChanHelpers.h

@@ -1,15 +0,0 @@
-#pragma once
-
-#include <xrpl/ledger/ApplyView.h>
-#include <xrpl/protocol/UintTypes.h>
-
-namespace xrpl {
-
-TER
-closeChannel(
-    std::shared_ptr<SLE> const& slep,
-    ApplyView& view,
-    uint256 const& key,
-    beast::Journal j);
-
-}  // namespace xrpl

src/test/app/Path_test.cpp

@@ -8,6 +8,7 @@
 #include <xrpld/rpc/detail/Tuning.h>
 
 #include <xrpl/beast/unit_test.h>
+#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_reader.h>
 #include <xrpl/protocol/ApiVersion.h>
@@ -131,7 +132,6 @@ public:
              c,
              Role::USER,
              {},
-             {},
              RPC::apiVersionIfUnspecified},
             {},
             {}};
@@ -155,11 +155,11 @@ public:
 
         Json::Value result;
         gate g;
-        app.getJobQueue().postCoro(jtCLIENT, "RPC-Client", [&](auto const& coro) {
+        app.getJobQueue().postCoroTask(jtCLIENT, "RPC-Client", [&](auto) -> CoroTask<void> {
             context.params = std::move(params);
-            context.coro = coro;
             RPC::doCommand(context, result);
             g.signal();
+            co_return;
         });
 
         using namespace std::chrono_literals;
@@ -240,28 +240,27 @@ public:
              c,
              Role::USER,
              {},
-             {},
              RPC::apiVersionIfUnspecified},
             {},
             {}};
         Json::Value result;
         gate g;
         // Test RPC::Tuning::max_src_cur source currencies.
-        app.getJobQueue().postCoro(jtCLIENT, "RPC-Client", [&](auto const& coro) {
+        app.getJobQueue().postCoroTask(jtCLIENT, "RPC-Client", [&](auto) -> CoroTask<void> {
             context.params = rpf(Account("alice"), Account("bob"), RPC::Tuning::max_src_cur);
-            context.coro = coro;
             RPC::doCommand(context, result);
             g.signal();
+            co_return;
         });
         BEAST_EXPECT(g.wait_for(5s));
         BEAST_EXPECT(!result.isMember(jss::error));
 
         // Test more than RPC::Tuning::max_src_cur source currencies.
-        app.getJobQueue().postCoro(jtCLIENT, "RPC-Client", [&](auto const& coro) {
+        app.getJobQueue().postCoroTask(jtCLIENT, "RPC-Client", [&](auto) -> CoroTask<void> {
             context.params = rpf(Account("alice"), Account("bob"), RPC::Tuning::max_src_cur + 1);
-            context.coro = coro;
             RPC::doCommand(context, result);
             g.signal();
+            co_return;
         });
         BEAST_EXPECT(g.wait_for(5s));
         BEAST_EXPECT(result.isMember(jss::error));
@@ -269,22 +268,22 @@ public:
         // Test RPC::Tuning::max_auto_src_cur source currencies.
         for (auto i = 0; i < (RPC::Tuning::max_auto_src_cur - 1); ++i)
             env.trust(Account("alice")[std::to_string(i + 100)](100), "bob");
-        app.getJobQueue().postCoro(jtCLIENT, "RPC-Client", [&](auto const& coro) {
+        app.getJobQueue().postCoroTask(jtCLIENT, "RPC-Client", [&](auto) -> CoroTask<void> {
             context.params = rpf(Account("alice"), Account("bob"), 0);
-            context.coro = coro;
             RPC::doCommand(context, result);
             g.signal();
+            co_return;
         });
         BEAST_EXPECT(g.wait_for(5s));
         BEAST_EXPECT(!result.isMember(jss::error));
 
         // Test more than RPC::Tuning::max_auto_src_cur source currencies.
         env.trust(Account("alice")["AUD"](100), "bob");
-        app.getJobQueue().postCoro(jtCLIENT, "RPC-Client", [&](auto const& coro) {
+        app.getJobQueue().postCoroTask(jtCLIENT, "RPC-Client", [&](auto) -> CoroTask<void> {
             context.params = rpf(Account("alice"), Account("bob"), 0);
-            context.coro = coro;
             RPC::doCommand(context, result);
             g.signal();
+            co_return;
         });
         BEAST_EXPECT(g.wait_for(5s));
         BEAST_EXPECT(result.isMember(jss::error));

src/test/core/CoroTask_test.cpp

@@ -0,0 +1,537 @@
+#include <test/jtx.h>
+
+#include <xrpl/core/JobQueue.h>
+#include <xrpl/core/JobQueueAwaiter.h>
+
+#include <chrono>
+#include <mutex>
+
+namespace xrpl {
+namespace test {
+
+/**
+ * Test suite for the C++20 coroutine primitives: CoroTask, CoroTaskRunner,
+ * and JobQueueAwaiter.
+ *
+ * Dependency Diagram
+ * ==================
+ *
+ *   CoroTask_test
+ *   +-------------------------------------------------+
+ *   | + gate (inner class) : condition_variable helper |
+ *   +-------------------------------------------------+
+ *          |  uses
+ *          v
+ *   jtx::Env  -->  JobQueue::postCoroTask()
+ *                       |
+ *                       +-- CoroTaskRunner (suspend / post / resume)
+ *                       +-- CoroTask<void> / CoroTask<T>
+ *                       +-- JobQueueAwaiter
+ *
+ * Test Coverage Matrix
+ * ====================
+ *
+ *   Test                      | Primitives exercised
+ *   --------------------------+----------------------------------------------
+ *   testVoidCompletion        | CoroTask<void> basic lifecycle
+ *   testCorrectOrder          | suspend() -> join() -> post() -> complete
+ *   testIncorrectOrder        | post() before suspend() (race-safe path)
+ *   testJobQueueAwaiter       | JobQueueAwaiter suspend + auto-repost
+ *   testThreadSpecificStorage | LocalValue isolation across coroutines
+ *   testExceptionPropagation  | unhandled_exception() in promise_type
+ *   testMultipleYields        | N sequential suspend/resume cycles
+ *   testValueReturn           | CoroTask<T> co_return value
+ *   testValueException        | CoroTask<T> exception via co_await
+ *   testValueChaining         | nested CoroTask<T> -> CoroTask<T>
+ *   testShutdownRejection     | postCoroTask returns nullptr when stopping
+ */
+class CoroTask_test : public beast::unit_test::suite
+{
+public:
+    /**
+     * Simple one-shot gate for synchronizing between test thread
+     * and coroutine worker threads. signal() sets the flag;
+     * wait_for() blocks until signaled or timeout.
+     */
+    class gate
+    {
+    private:
+        std::condition_variable cv_;
+        std::mutex mutex_;
+        bool signaled_ = false;
+
+    public:
+        /**
+         * Block until signaled or timeout expires.
+         *
+         * @param rel_time Maximum duration to wait
+         *
+         * @return true if signaled before timeout
+         */
+        template <class Rep, class Period>
+        bool
+        wait_for(std::chrono::duration<Rep, Period> const& rel_time)
+        {
+            std::unique_lock<std::mutex> lk(mutex_);
+            auto b = cv_.wait_for(lk, rel_time, [this] { return signaled_; });
+            signaled_ = false;
+            return b;
+        }
+
+        /**
+         * Signal the gate, waking any waiting thread.
+         */
+        void
+        signal()
+        {
+            std::lock_guard lk(mutex_);
+            signaled_ = true;
+            cv_.notify_all();
+        }
+    };
+
+    // NOTE: All coroutine lambdas passed to postCoroTask use explicit
+    // pointer-by-value captures instead of [&] to work around a GCC 14
+    // bug where reference captures in coroutine lambdas are corrupted
+    // in the coroutine frame.
+
+    /**
+     * CoroTask<void> runs to completion and runner becomes non-runnable.
+     */
+    void
+    testVoidCompletion()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("void completion");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [gp = &g](auto) -> CoroTask<void> {
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+        BEAST_EXPECT(g.wait_for(5s));
+        runner->join();
+        BEAST_EXPECT(!runner->runnable());
+    }
+
+    /**
+     * Correct order: suspend, join, post, complete.
+     * Mirrors existing Coroutine_test::correct_order.
+     */
+    void
+    testCorrectOrder()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("correct order");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g1, g2;
+        std::shared_ptr<JobQueue::CoroTaskRunner> r;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT,
+            "CoroTaskTest",
+            [rp = &r, g1p = &g1, g2p = &g2](auto runner) -> CoroTask<void> {
+                *rp = runner;
+                g1p->signal();
+                co_await runner->suspend();
+                g2p->signal();
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+        BEAST_EXPECT(g1.wait_for(5s));
+        runner->join();
+        runner->post();
+        BEAST_EXPECT(g2.wait_for(5s));
+        runner->join();
+    }
+
+    /**
+     * Incorrect order: post() before suspend(). Verifies the
+     * race-safe path. Mirrors Coroutine_test::incorrect_order.
+     */
+    void
+    testIncorrectOrder()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("incorrect order");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [gp = &g](auto runner) -> CoroTask<void> {
+                runner->post();
+                co_await runner->suspend();
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(g.wait_for(5s));
+    }
+
+    /**
+     * JobQueueAwaiter suspend + auto-repost across multiple yield points.
+     */
+    void
+    testJobQueueAwaiter()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("JobQueueAwaiter");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        int step = 0;
+        env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [sp = &step, gp = &g](auto runner) -> CoroTask<void> {
+                *sp = 1;
+                co_await runner->yieldAndPost();
+                *sp = 2;
+                co_await runner->yieldAndPost();
+                *sp = 3;
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(g.wait_for(5s));
+        BEAST_EXPECT(step == 3);
+    }
+
+    /**
+     * Per-coroutine LocalValue isolation. Each coroutine sees its own
+     * copy of thread-local state. Mirrors Coroutine_test::thread_specific_storage.
+     */
+    void
+    testThreadSpecificStorage()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("thread specific storage");
+        Env env(*this);
+
+        auto& jq = env.app().getJobQueue();
+
+        static int const N = 4;
+        std::array<std::shared_ptr<JobQueue::CoroTaskRunner>, N> a;
+
+        LocalValue<int> lv(-1);
+        BEAST_EXPECT(*lv == -1);
+
+        gate g;
+        jq.addJob(jtCLIENT, "LocalValTest", [&]() {
+            this->BEAST_EXPECT(*lv == -1);
+            *lv = -2;
+            this->BEAST_EXPECT(*lv == -2);
+            g.signal();
+        });
+        BEAST_EXPECT(g.wait_for(5s));
+        BEAST_EXPECT(*lv == -1);
+
+        for (int i = 0; i < N; ++i)
+        {
+            jq.postCoroTask(
+                jtCLIENT,
+                "CoroTaskTest",
+                [this, ap = &a, gp = &g, lvp = &lv, id = i](auto runner) -> CoroTask<void> {
+                    (*ap)[id] = runner;
+                    gp->signal();
+                    co_await runner->suspend();
+
+                    this->BEAST_EXPECT(**lvp == -1);
+                    **lvp = id;
+                    this->BEAST_EXPECT(**lvp == id);
+                    gp->signal();
+                    co_await runner->suspend();
+
+                    this->BEAST_EXPECT(**lvp == id);
+                    co_return;
+                });
+            BEAST_EXPECT(g.wait_for(5s));
+            a[i]->join();
+        }
+        for (auto const& r : a)
+        {
+            r->post();
+            BEAST_EXPECT(g.wait_for(5s));
+            r->join();
+        }
+        for (auto const& r : a)
+        {
+            r->post();
+            r->join();
+        }
+
+        jq.addJob(jtCLIENT, "LocalValTest", [&]() {
+            this->BEAST_EXPECT(*lv == -2);
+            g.signal();
+        });
+        BEAST_EXPECT(g.wait_for(5s));
+        BEAST_EXPECT(*lv == -1);
+    }
+
+    /**
+     * Exception thrown in coroutine body is caught by
+     * promise_type::unhandled_exception(). Coroutine completes.
+     */
+    void
+    testExceptionPropagation()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("exception propagation");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [gp = &g](auto) -> CoroTask<void> {
+                gp->signal();
+                throw std::runtime_error("test exception");
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+        BEAST_EXPECT(g.wait_for(5s));
+        runner->join();
+        // The exception is caught by promise_type::unhandled_exception()
+        // and the coroutine is considered done
+        BEAST_EXPECT(!runner->runnable());
+    }
+
+    /**
+     * Multiple sequential suspend/resume cycles via co_await.
+     */
+    void
+    testMultipleYields()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("multiple yields");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        int counter = 0;
+        std::shared_ptr<JobQueue::CoroTaskRunner> r;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT,
+            "CoroTaskTest",
+            [rp = &r, cp = &counter, gp = &g](auto runner) -> CoroTask<void> {
+                *rp = runner;
+                ++(*cp);
+                gp->signal();
+                co_await runner->suspend();
+                ++(*cp);
+                gp->signal();
+                co_await runner->suspend();
+                ++(*cp);
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+
+        BEAST_EXPECT(g.wait_for(5s));
+        BEAST_EXPECT(counter == 1);
+        runner->join();
+
+        runner->post();
+        BEAST_EXPECT(g.wait_for(5s));
+        BEAST_EXPECT(counter == 2);
+        runner->join();
+
+        runner->post();
+        BEAST_EXPECT(g.wait_for(5s));
+        BEAST_EXPECT(counter == 3);
+        runner->join();
+        BEAST_EXPECT(!runner->runnable());
+    }
+
+    /**
+     * CoroTask<T> returns a value via co_return. Outer coroutine
+     * extracts it with co_await.
+     */
+    void
+    testValueReturn()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("value return");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        int result = 0;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [rp = &result, gp = &g](auto) -> CoroTask<void> {
+                auto inner = []() -> CoroTask<int> { co_return 42; };
+                *rp = co_await inner();
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+        BEAST_EXPECT(g.wait_for(5s));
+        runner->join();
+        BEAST_EXPECT(result == 42);
+        BEAST_EXPECT(!runner->runnable());
+    }
+
+    /**
+     * CoroTask<T> propagates exceptions from inner coroutines.
+     * Outer coroutine catches via try/catch around co_await.
+     */
+    void
+    testValueException()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("value exception");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        bool caught = false;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [cp = &caught, gp = &g](auto) -> CoroTask<void> {
+                auto inner = []() -> CoroTask<int> {
+                    throw std::runtime_error("inner error");
+                    co_return 0;
+                };
+                try
+                {
+                    co_await inner();
+                }
+                catch (std::runtime_error const& e)
+                {
+                    *cp = true;
+                }
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+        BEAST_EXPECT(g.wait_for(5s));
+        runner->join();
+        BEAST_EXPECT(caught);
+        BEAST_EXPECT(!runner->runnable());
+    }
+
+    /**
+     * CoroTask<T> chaining. Nested value-returning coroutines
+     * compose via co_await.
+     */
+    void
+    testValueChaining()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("value chaining");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        gate g;
+        int result = 0;
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [rp = &result, gp = &g](auto) -> CoroTask<void> {
+                auto add = [](int a, int b) -> CoroTask<int> { co_return a + b; };
+                auto mul = [add](int a, int b) -> CoroTask<int> {
+                    int sum = co_await add(a, b);
+                    co_return sum * 2;
+                };
+                *rp = co_await mul(3, 4);
+                gp->signal();
+                co_return;
+            });
+        BEAST_EXPECT(runner);
+        BEAST_EXPECT(g.wait_for(5s));
+        runner->join();
+        BEAST_EXPECT(result == 14);  // (3 + 4) * 2
+        BEAST_EXPECT(!runner->runnable());
+    }
+
+    /**
+     * postCoroTask returns nullptr when JobQueue is stopping.
+     */
+    void
+    testShutdownRejection()
+    {
+        using namespace std::chrono_literals;
+        using namespace jtx;
+
+        testcase("shutdown rejection");
+
+        Env env(*this, envconfig([](std::unique_ptr<Config> cfg) {
+            cfg->FORCE_MULTI_THREAD = true;
+            return cfg;
+        }));
+
+        // Stop the JobQueue
+        env.app().getJobQueue().stop();
+
+        auto runner = env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTaskTest", [](auto) -> CoroTask<void> { co_return; });
+        BEAST_EXPECT(!runner);
+    }
+
+    void
+    run() override
+    {
+        testVoidCompletion();
+        testCorrectOrder();
+        testIncorrectOrder();
+        testJobQueueAwaiter();
+        testThreadSpecificStorage();
+        testExceptionPropagation();
+        testMultipleYields();
+        testValueReturn();
+        testValueException();
+        testValueChaining();
+        testShutdownRejection();
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(CoroTask, core, xrpl);
+
+}  // namespace test
+}  // namespace xrpl

src/test/core/Coroutine_test.cpp

@@ -40,6 +40,11 @@ public:
         }
     };
 
+    // NOTE: All coroutine lambdas passed to postCoroTask use explicit
+    // pointer-by-value captures instead of [&] to work around a GCC 14
+    // bug where reference captures in coroutine lambdas are corrupted
+    // in the coroutine frame.
+
     void
     correct_order()
     {
@@ -54,13 +59,15 @@ public:
         }));
 
         gate g1, g2;
-        std::shared_ptr<JobQueue::Coro> c;
-        env.app().getJobQueue().postCoro(jtCLIENT, "CoroTest", [&](auto const& cr) {
-            c = cr;
-            g1.signal();
-            c->yield();
-            g2.signal();
-        });
+        std::shared_ptr<JobQueue::CoroTaskRunner> c;
+        env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTest", [cp = &c, g1p = &g1, g2p = &g2](auto runner) -> CoroTask<void> {
+                *cp = runner;
+                g1p->signal();
+                co_await runner->suspend();
+                g2p->signal();
+                co_return;
+            });
         BEAST_EXPECT(g1.wait_for(5s));
         c->join();
         c->post();
@@ -81,11 +88,17 @@ public:
         }));
 
         gate g;
-        env.app().getJobQueue().postCoro(jtCLIENT, "CoroTest", [&](auto const& c) {
-            c->post();
-            c->yield();
-            g.signal();
-        });
+        env.app().getJobQueue().postCoroTask(
+            jtCLIENT, "CoroTest", [gp = &g](auto runner) -> CoroTask<void> {
+                // Schedule a resume before suspending.  The posted job
+                // cannot actually call resume() until the current resume()
+                // releases CoroTaskRunner::mutex_, which only happens after
+                // the coroutine suspends at co_await.
+                runner->post();
+                co_await runner->suspend();
+                gp->signal();
+                co_return;
+            });
         BEAST_EXPECT(g.wait_for(5s));
     }
 
@@ -101,7 +114,7 @@ public:
         auto& jq = env.app().getJobQueue();
 
         static int const N = 4;
-        std::array<std::shared_ptr<JobQueue::Coro>, N> a;
+        std::array<std::shared_ptr<JobQueue::CoroTaskRunner>, N> a;
 
         LocalValue<int> lv(-1);
         BEAST_EXPECT(*lv == -1);
@@ -118,19 +131,23 @@ public:
 
         for (int i = 0; i < N; ++i)
         {
-            jq.postCoro(jtCLIENT, "CoroTest", [&, id = i](auto const& c) {
-                a[id] = c;
-                g.signal();
-                c->yield();
+            jq.postCoroTask(
+                jtCLIENT,
+                "CoroTest",
+                [this, ap = &a, gp = &g, lvp = &lv, id = i](auto runner) -> CoroTask<void> {
+                    (*ap)[id] = runner;
+                    gp->signal();
+                    co_await runner->suspend();
 
-                this->BEAST_EXPECT(*lv == -1);
-                *lv = id;
-                this->BEAST_EXPECT(*lv == id);
-                g.signal();
-                c->yield();
+                    this->BEAST_EXPECT(**lvp == -1);
+                    **lvp = id;
+                    this->BEAST_EXPECT(**lvp == id);
+                    gp->signal();
+                    co_await runner->suspend();
 
-                this->BEAST_EXPECT(*lv == id);
-            });
+                    this->BEAST_EXPECT(**lvp == id);
+                    co_return;
+                });
             BEAST_EXPECT(g.wait_for(5s));
             a[i]->join();
         }

src/test/core/JobQueue_test.cpp

@@ -43,87 +43,91 @@ class JobQueue_test : public beast::unit_test::suite
         }
     }
 
+    // NOTE: All coroutine lambdas passed to postCoroTask use explicit
+    // pointer-by-value captures instead of [&] to work around a GCC 14
+    // bug where reference captures in coroutine lambdas are corrupted
+    // in the coroutine frame.
+
     void
-    testPostCoro()
+    testPostCoroTask()
     {
         jtx::Env env{*this};
 
         JobQueue& jQueue = env.app().getJobQueue();
         {
-            // Test repeated post()s until the Coro completes.
+            // Test repeated post()s until the coroutine completes.
             std::atomic<int> yieldCount{0};
-            auto const coro = jQueue.postCoro(
-                jtCLIENT,
-                "PostCoroTest1",
-                [&yieldCount](std::shared_ptr<JobQueue::Coro> const& coroCopy) {
-                    while (++yieldCount < 4)
-                        coroCopy->yield();
+            auto const runner = jQueue.postCoroTask(
+                jtCLIENT, "PostCoroTest1", [ycp = &yieldCount](auto runner) -> CoroTask<void> {
+                    while (++(*ycp) < 4)
+                        co_await runner->suspend();
+                    co_return;
                 });
-            BEAST_EXPECT(coro != nullptr);
+            BEAST_EXPECT(runner != nullptr);
 
             // Wait for the Job to run and yield.
             while (yieldCount == 0)
                 ;
 
-            // Now re-post until the Coro says it is done.
+            // Now re-post until the CoroTaskRunner says it is done.
             int old = yieldCount;
-            while (coro->runnable())
+            while (runner->runnable())
             {
-                BEAST_EXPECT(coro->post());
+                BEAST_EXPECT(runner->post());
                 while (old == yieldCount)
                 {
                 }
-                coro->join();
+                runner->join();
                 BEAST_EXPECT(++old == yieldCount);
             }
             BEAST_EXPECT(yieldCount == 4);
         }
         {
-            // Test repeated resume()s until the Coro completes.
+            // Test repeated resume()s until the coroutine completes.
             int yieldCount{0};
-            auto const coro = jQueue.postCoro(
-                jtCLIENT,
-                "PostCoroTest2",
-                [&yieldCount](std::shared_ptr<JobQueue::Coro> const& coroCopy) {
-                    while (++yieldCount < 4)
-                        coroCopy->yield();
+            auto const runner = jQueue.postCoroTask(
+                jtCLIENT, "PostCoroTest2", [ycp = &yieldCount](auto runner) -> CoroTask<void> {
+                    while (++(*ycp) < 4)
+                        co_await runner->suspend();
+                    co_return;
                 });
-            if (!coro)
+            if (!runner)
             {
-                // There's no good reason we should not get a Coro, but we
+                // There's no good reason we should not get a runner, but we
                 // can't continue without one.
                 BEAST_EXPECT(false);
                 return;
             }
 
             // Wait for the Job to run and yield.
-            coro->join();
+            runner->join();
 
-            // Now resume until the Coro says it is done.
+            // Now resume until the CoroTaskRunner says it is done.
             int old = yieldCount;
-            while (coro->runnable())
+            while (runner->runnable())
             {
-                coro->resume();  // Resume runs synchronously on this thread.
+                runner->resume();  // Resume runs synchronously on this thread.
                 BEAST_EXPECT(++old == yieldCount);
             }
             BEAST_EXPECT(yieldCount == 4);
         }
         {
             // If the JobQueue is stopped, we should no
-            // longer be able to add a Coro (and calling postCoro() should
-            // return false).
+            // longer be able to post a coroutine (and calling postCoroTask()
+            // should return nullptr).
             using namespace std::chrono_literals;
             jQueue.stop();
 
-            // The Coro should never run, so having the Coro access this
+            // The coroutine should never run, so having it access this
             // unprotected variable on the stack should be completely safe.
             // Not recommended for the faint of heart...
             bool unprotected;
-            auto const coro = jQueue.postCoro(
-                jtCLIENT, "PostCoroTest3", [&unprotected](std::shared_ptr<JobQueue::Coro> const&) {
-                    unprotected = false;
+            auto const runner = jQueue.postCoroTask(
+                jtCLIENT, "PostCoroTest3", [up = &unprotected](auto) -> CoroTask<void> {
+                    *up = false;
+                    co_return;
                 });
-            BEAST_EXPECT(coro == nullptr);
+            BEAST_EXPECT(runner == nullptr);
         }
     }
 
@@ -132,7 +136,7 @@ public:
     run() override
     {
         testAddJob();
-        testPostCoro();
+        testPostCoroTask();
     }
 };
 

src/test/jtx/Env_test.cpp

@@ -39,9 +39,9 @@ public:
             a = std::move(b);
             Account c(std::move(a));
         }
-        Account("alice");
-        Account("alice", KeyType::secp256k1);
-        Account("alice", KeyType::ed25519);
+        Account("alice");                      // NOLINT(bugprone-unused-raii)
+        Account("alice", KeyType::secp256k1);  // NOLINT(bugprone-unused-raii)
+        Account("alice", KeyType::ed25519);    // NOLINT(bugprone-unused-raii)
         auto const gw = Account("gw");
         [](AccountID) {}(gw);
         auto const USD = gw["USD"];
@@ -56,11 +56,11 @@ public:
     {
         using namespace jtx;
 
-        PrettyAmount(0);
-        PrettyAmount(1);
-        PrettyAmount(0u);
-        PrettyAmount(1u);
-        PrettyAmount(-1);
+        PrettyAmount(0);   // NOLINT(bugprone-unused-raii)
+        PrettyAmount(1);   // NOLINT(bugprone-unused-raii)
+        PrettyAmount(0u);  // NOLINT(bugprone-unused-raii)
+        PrettyAmount(1u);  // NOLINT(bugprone-unused-raii)
+        PrettyAmount(-1);  // NOLINT(bugprone-unused-raii)
         static_assert(!std::is_trivially_constructible<PrettyAmount, char>::value, "");
         static_assert(!std::is_trivially_constructible<PrettyAmount, unsigned char>::value, "");
         static_assert(!std::is_trivially_constructible<PrettyAmount, short>::value, "");

src/test/jtx/impl/AMMTest.cpp

@@ -6,6 +6,7 @@
 
 #include <xrpld/rpc/RPCHandler.h>
 
+#include <xrpl/core/CoroTask.h>
 #include <xrpl/protocol/ApiVersion.h>
 #include <xrpl/protocol/STParsedJSON.h>
 #include <xrpl/resource/Fees.h>
@@ -193,7 +194,6 @@ AMMTest::find_paths_request(
          c,
          Role::USER,
          {},
-         {},
          RPC::apiVersionIfUnspecified},
         {},
         {}};
@@ -215,11 +215,11 @@ AMMTest::find_paths_request(
 
     Json::Value result;
     gate g;
-    app.getJobQueue().postCoro(jtCLIENT, "RPC-Client", [&](auto const& coro) {
+    app.getJobQueue().postCoroTask(jtCLIENT, "RPC-Client", [&](auto) -> CoroTask<void> {
         context.params = std::move(params);
-        context.coro = coro;
         RPC::doCommand(context, result);
         g.signal();
+        co_return;
     });
 
     using namespace std::chrono_literals;

src/xrpld/app/main/Application.cpp

@@ -1431,7 +1431,6 @@ ApplicationImp::setup(boost::program_options::variables_map const& cmdline)
              c,
              Role::ADMIN,
              {},
-             {},
              RPC::apiMaximumSupportedVersion},
             jvCommand};
 

src/xrpld/app/main/GRPCServer.cpp

@@ -3,6 +3,7 @@
 
 #include <xrpl/beast/core/CurrentThreadName.h>
 #include <xrpl/beast/net/IPAddressConversion.h>
+#include <xrpl/core/CoroTask.h>
 #include <xrpl/resource/Fees.h>
 
 namespace xrpl {
@@ -99,13 +100,14 @@ GRPCServerImpl::CallData<Request, Response>::process()
     // ensures that finished is always true when this CallData object
     // is returned as a tag in handleRpcs(), after sending the response
     finished_ = true;
-    auto coro = app_.getJobQueue().postCoro(
-        JobType::jtRPC, "gRPC-Client", [thisShared](std::shared_ptr<JobQueue::Coro> coro) {
-            thisShared->process(coro);
+    auto runner = app_.getJobQueue().postCoroTask(
+        JobType::jtRPC, "gRPC-Client", [thisShared](auto) -> CoroTask<void> {
+            thisShared->processRequest();
+            co_return;
         });
 
-    // If coro is null, then the JobQueue has already been shutdown
-    if (!coro)
+    // If runner is null, then the JobQueue has already been shutdown
+    if (!runner)
     {
         grpc::Status status{grpc::StatusCode::INTERNAL, "Job Queue is already stopped"};
         responder_.FinishWithError(status, this);
@@ -114,7 +116,7 @@ GRPCServerImpl::CallData<Request, Response>::process()
 
 template <class Request, class Response>
 void
-GRPCServerImpl::CallData<Request, Response>::process(std::shared_ptr<JobQueue::Coro> coro)
+GRPCServerImpl::CallData<Request, Response>::processRequest()
 {
     try
     {
@@ -156,7 +158,6 @@ GRPCServerImpl::CallData<Request, Response>::process(std::shared_ptr<JobQueue::C
                  app_.getLedgerMaster(),
                  usage,
                  role,
-                 coro,
                  InfoSub::pointer(),
                  apiVersion},
                 request_};

src/xrpld/app/main/GRPCServer.h

@@ -206,9 +206,12 @@ private:
         clone() override;
 
     private:
-        // process the request. Called inside the coroutine passed to JobQueue
+        /**
+         * Process the gRPC request. Called inside the CoroTask lambda
+         * posted to the JobQueue by process().
+         */
         void
-        process(std::shared_ptr<JobQueue::Coro> coro);
+        processRequest();
 
         // return load type of this RPC
         Resource::Charge

src/xrpld/rpc/Context.h

@@ -3,7 +3,6 @@
 #include <xrpld/rpc/Role.h>
 
 #include <xrpl/beast/utility/Journal.h>
-#include <xrpl/core/JobQueue.h>
 #include <xrpl/server/InfoSub.h>
 
 namespace xrpl {
@@ -24,7 +23,6 @@ struct Context
     LedgerMaster& ledgerMaster;
     Resource::Consumer& consumer;
     Role role;
-    std::shared_ptr<JobQueue::Coro> coro{};
     InfoSub::pointer infoSub{};
     unsigned int apiVersion;
 };

src/xrpld/rpc/ServerHandler.h

@@ -169,13 +169,10 @@ public:
 
 private:
     Json::Value
-    processSession(
-        std::shared_ptr<WSSession> const& session,
-        std::shared_ptr<JobQueue::Coro> const& coro,
-        Json::Value const& jv);
+    processSession(std::shared_ptr<WSSession> const& session, Json::Value const& jv);
 
     void
-    processSession(std::shared_ptr<Session> const&, std::shared_ptr<JobQueue::Coro> coro);
+    processSession(std::shared_ptr<Session> const&);
 
     void
     processRequest(
@@ -183,7 +180,6 @@ private:
         std::string const& request,
         beast::IP::Endpoint const& remoteIPAddress,
         Output&&,
-        std::shared_ptr<JobQueue::Coro> coro,
         std::string_view forwardedFor,
         std::string_view user);
 

src/xrpld/rpc/detail/ServerHandler.cpp

@@ -14,6 +14,7 @@
 #include <xrpl/basics/make_SSLContext.h>
 #include <xrpl/beast/net/IPAddressConversion.h>
 #include <xrpl/beast/rfc2616.h>
+#include <xrpl/core/CoroTask.h>
 #include <xrpl/core/JobQueue.h>
 #include <xrpl/json/json_reader.h>
 #include <xrpl/json/to_string.h>
@@ -284,9 +285,17 @@ ServerHandler::onRequest(Session& session)
     }
 
     std::shared_ptr<Session> detachedSession = session.detach();
-    auto const postResult = m_jobQueue.postCoro(
-        jtCLIENT_RPC, "RPC-Client", [this, detachedSession](std::shared_ptr<JobQueue::Coro> coro) {
-            processSession(detachedSession, coro);
+    auto const postResult = m_jobQueue.postCoroTask(
+        jtCLIENT_RPC, "RPC-Client", [this, detachedSession](auto) -> CoroTask<void> {
+            try
+            {
+                processSession(detachedSession);
+            }
+            catch (std::exception const& e)
+            {
+                JLOG(m_journal.error()) << "RPC-Client coroutine exception: " << e.what();
+            }
+            co_return;
         });
     if (postResult == nullptr)
     {
@@ -322,17 +331,26 @@ ServerHandler::onWSMessage(
 
     JLOG(m_journal.trace()) << "Websocket received '" << jv << "'";
 
-    auto const postResult = m_jobQueue.postCoro(
+    auto const postResult = m_jobQueue.postCoroTask(
         jtCLIENT_WEBSOCKET,
         "WS-Client",
-        [this, session, jv = std::move(jv)](std::shared_ptr<JobQueue::Coro> const& coro) {
-            auto const jr = this->processSession(session, coro, jv);
-            auto const s = to_string(jr);
-            auto const n = s.length();
-            boost::beast::multi_buffer sb(n);
-            sb.commit(boost::asio::buffer_copy(sb.prepare(n), boost::asio::buffer(s.c_str(), n)));
-            session->send(std::make_shared<StreambufWSMsg<decltype(sb)>>(std::move(sb)));
-            session->complete();
+        [this, session, jv = std::move(jv)](auto) -> CoroTask<void> {
+            try
+            {
+                auto const jr = this->processSession(session, jv);
+                auto const s = to_string(jr);
+                auto const n = s.length();
+                boost::beast::multi_buffer sb(n);
+                sb.commit(
+                    boost::asio::buffer_copy(sb.prepare(n), boost::asio::buffer(s.c_str(), n)));
+                session->send(std::make_shared<StreambufWSMsg<decltype(sb)>>(std::move(sb)));
+                session->complete();
+            }
+            catch (std::exception const& e)
+            {
+                JLOG(m_journal.error()) << "WS-Client coroutine exception: " << e.what();
+            }
+            co_return;
         });
     if (postResult == nullptr)
     {
@@ -373,10 +391,7 @@ logDuration(Json::Value const& request, T const& duration, beast::Journal& journ
 }
 
 Json::Value
-ServerHandler::processSession(
-    std::shared_ptr<WSSession> const& session,
-    std::shared_ptr<JobQueue::Coro> const& coro,
-    Json::Value const& jv)
+ServerHandler::processSession(std::shared_ptr<WSSession> const& session, Json::Value const& jv)
 {
     auto is = std::static_pointer_cast<WSInfoSub>(session->appDefined);
     if (is->getConsumer().disconnect(m_journal))
@@ -443,7 +458,6 @@ ServerHandler::processSession(
                  app_.getLedgerMaster(),
                  is->getConsumer(),
                  role,
-                 coro,
                  is,
                  apiVersion},
                 jv,
@@ -514,18 +528,14 @@ ServerHandler::processSession(
     return jr;
 }
 
-// Run as a coroutine.
 void
-ServerHandler::processSession(
-    std::shared_ptr<Session> const& session,
-    std::shared_ptr<JobQueue::Coro> coro)
+ServerHandler::processSession(std::shared_ptr<Session> const& session)
 {
     processRequest(
         session->port(),
         buffers_to_string(session->request().body().data()),
         session->remoteAddress().at_port(0),
         makeOutput(*session),
-        coro,
         forwardedFor(session->request()),
         [&] {
             auto const iter = session->request().find("X-User");
@@ -562,7 +572,6 @@ ServerHandler::processRequest(
     std::string const& request,
     beast::IP::Endpoint const& remoteIPAddress,
     Output&& output,
-    std::shared_ptr<JobQueue::Coro> coro,
     std::string_view forwardedFor,
     std::string_view user)
 {
@@ -819,7 +828,6 @@ ServerHandler::processRequest(
              app_.getLedgerMaster(),
              usage,
              role,
-             coro,
              InfoSub::pointer(),
              apiVersion},
             params,

src/xrpld/rpc/handlers/RipplePathFind.cpp

@@ -7,6 +7,9 @@
 #include <xrpl/protocol/RPCErr.h>
 #include <xrpl/resource/Fees.h>
 
+#include <condition_variable>
+#include <mutex>
+
 namespace xrpl {
 
 // This interface is deprecated.
@@ -37,98 +40,40 @@ doRipplePathFind(RPC::JsonContext& context)
         PathRequest::pointer request;
         lpLedger = context.ledgerMaster.getClosedLedger();
 
-        // It doesn't look like there's much odd happening here, but you should
-        // be aware this code runs in a JobQueue::Coro, which is a coroutine.
-        // And we may be flipping around between threads.  Here's an overview:
-        //
-        // 1. We're running doRipplePathFind() due to a call to
-        //    ripple_path_find.  doRipplePathFind() is currently running
-        //    inside of a JobQueue::Coro using a JobQueue thread.
-        //
-        // 2. doRipplePathFind's call to makeLegacyPathRequest() enqueues the
-        //    path-finding request.  That request will (probably) run at some
-        //    indeterminate future time on a (probably different) JobQueue
-        //    thread.
-        //
-        // 3. As a continuation from that path-finding JobQueue thread, the
-        //    coroutine we're currently running in (!) is posted to the
-        //    JobQueue.  Because it is a continuation, that post won't
-        //    happen until the path-finding request completes.
-        //
-        // 4. Once the continuation is enqueued, and we have reason to think
-        //    the path-finding job is likely to run, then the coroutine we're
-        //    running in yield()s.  That means it surrenders its thread in
-        //    the JobQueue.  The coroutine is suspended, but ready to run,
-        //    because it is kept resident by a shared_ptr in the
-        //    path-finding continuation.
-        //
-        // 5. If all goes well then path-finding runs on a JobQueue thread
-        //    and executes its continuation.  The continuation posts this
-        //    same coroutine (!) to the JobQueue.
-        //
-        // 6. When the JobQueue calls this coroutine, this coroutine resumes
-        //    from the line below the coro->yield() and returns the
-        //    path-finding result.
-        //
-        // With so many moving parts, what could go wrong?
-        //
-        // Just in terms of the JobQueue refusing to add jobs at shutdown
-        // there are two specific things that can go wrong.
-        //
-        // 1. The path-finding Job queued by makeLegacyPathRequest() might be
-        //    rejected (because we're shutting down).
-        //
-        //    Fortunately this problem can be addressed by looking at the
-        //    return value of makeLegacyPathRequest().  If
-        //    makeLegacyPathRequest() cannot get a thread to run the path-find
-        //    on, then it returns an empty request.
-        //
-        // 2. The path-finding job might run, but the Coro::post() might be
-        //    rejected by the JobQueue (because we're shutting down).
-        //
-        //    We handle this case by resuming (not posting) the Coro.
-        //    By resuming the Coro, we allow the Coro to run to completion
-        //    on the current thread instead of requiring that it run on a
-        //    new thread from the JobQueue.
-        //
-        // Both of these failure modes are hard to recreate in a unit test
-        // because they are so dependent on inter-thread timing.  However
-        // the failure modes can be observed by synchronously (inside the
-        // rippled source code) shutting down the application.  The code to
-        // do so looks like this:
-        //
-        //   context.app.signalStop();
-        //   while (! context.app.getJobQueue().jobCounter().joined()) { }
-        //
-        // The first line starts the process of shutting down the app.
-        // The second line waits until no more jobs can be added to the
-        // JobQueue before letting the thread continue.
-        //
-        // May 2017
+        // makeLegacyPathRequest enqueues a path-finding job that runs
+        // asynchronously.  We block this thread with a condition_variable
+        // until the path-finding continuation signals completion.
+        // If makeLegacyPathRequest cannot schedule the job (e.g. during
+        // shutdown), it returns an empty request and we skip the wait.
+        // Replaces the old Coro yield/resume pattern with synchronous
+        // blocking, eliminating shutdown race conditions.
+        std::mutex mtx;
+        std::condition_variable cv;
+        bool pathDone = false;
+
         jvResult = context.app.getPathRequests().makeLegacyPathRequest(
             request,
-            [&context]() {
-                // Copying the shared_ptr keeps the coroutine alive up
-                // through the return.  Otherwise the storage under the
-                // captured reference could evaporate when we return from
-                // coroCopy->resume().  This is not strictly necessary, but
-                // will make maintenance easier.
-                std::shared_ptr<JobQueue::Coro> coroCopy{context.coro};
-                if (!coroCopy->post())
+            [&]() {
                 {
-                    // The post() failed, so we won't get a thread to let
-                    // the Coro finish.  We'll call Coro::resume() so the
-                    // Coro can finish on our thread.  Otherwise the
-                    // application will hang on shutdown.
-                    coroCopy->resume();
+                    std::lock_guard lk(mtx);
+                    pathDone = true;
                 }
+                cv.notify_one();
             },
             context.consumer,
             lpLedger,
             context.params);
         if (request)
         {
-            context.coro->yield();
+            using namespace std::chrono_literals;
+            std::unique_lock lk(mtx);
+            if (!cv.wait_for(lk, 30s, [&] { return pathDone; }))
+            {
+                // Path-finding continuation never fired (e.g. shutdown
+                // race or unexpected failure). Return an internal error
+                // rather than blocking the RPC thread indefinitely.
+                return rpcError(rpcINTERNAL);
+            }
             jvResult = request->doStatus(context.params);
         }