refactor: Extract invariant invocation into free checkInvariants runner

Move the invariant-check orchestration out of ApplyContext and Transactor
into a free function xrpl::checkInvariants(ApplyContext&, TER, XRPAmount,
optional<reference_wrapper<InvariantCheck>>).

The two previously separate traversals (one in ApplyContext driving the
protocol tuple fold, one in Transactor driving the tx-specific check) are
merged into a single ctx.visit walk.  Per-layer try/catch inside the
lambda isolates collection faults: a throw in one layer stops only that
layer from visiting further entries while the other continues.  A layer
whose collection faulted skips its finalize phase.

ApplyContext loses checkInvariants/checkInvariantsHelper/failInvariantCheck.
Transactor delegates to the free runner via a private InvariantCheckAdapter
that bridges visitInvariantEntry+finalizeInvariants into the InvariantCheck
interface.  A SkipTxInvariants::Yes/No enum makes the fee-claim-reset call
site explicit about omitting the tx-specific check.

Protocol checks remain duck-typed in the InvariantChecks tuple (static
dispatch, no vtable on the hot path).  InvariantCheck is the runtime
interface used only by InvariantCheckAdapter.

.github/workflows/conflicting-pr.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check if PRs are dirty
-        uses: eps1lon/actions-label-merge-conflict@1df065ebe6e3310545d4f4c4e862e43bdca146f0 # v3.0.3
+        uses: eps1lon/actions-label-merge-conflict@0273be72a0bbd58fcd71d0d6c02c209b50d1e5e1 # v3.1.0
         with:
           dirtyLabel: "PR: has conflicts"
           repoToken: "${{ secrets.GITHUB_TOKEN }}"

cfg/xrpld-example.cfg

@@ -953,6 +953,21 @@
 #
 #   Optional keys for NuDB and RocksDB:
 #
+#       cache_size          Size of cache for database records. Default is 16384.
+#                           Setting this value to 0 will use the default value.
+#
+#       cache_age           Length of time in minutes to keep database records
+#                           cached. Default is 5 minutes. Setting this value to
+#                           0 will use the default value.
+#
+#                           Note: if cache_size or cache_age is not specified,
+#                           default values will be used for the unspecified
+#                           parameter.
+#
+#                           Note: the cache will not be created if online_delete
+#                           is specified, because the rotating NodeStore does
+#                           not use this cache).
+#
 #       fast_load           Boolean. If set, load the last persisted ledger
 #                           from disk upon process start before syncing to
 #                           the network. This is likely to improve performance

cmake/scripts/codegen/templates/LedgerEntry.h.mako

@@ -33,7 +33,7 @@ public:
      * @brief Construct a ${name} ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit ${name}(std::shared_ptr<SLE const> sle)
+    explicit ${name}(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -168,7 +168,7 @@ ${field['typeData']['setter_type']} ${field['paramName']}${',' if i < len(requir
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    ${name}Builder(std::shared_ptr<SLE const> sle)
+    ${name}Builder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ${tag})
         {

cspell.config.yaml

@@ -134,6 +134,7 @@ words:
   - iou
   - ious
   - isrdc
+  - isystem
   - itype
   - jemalloc
   - jlog

docker/check-sanitizers.sh

@@ -1,48 +0,0 @@
-#!/bin/bash
-
-# Sanity-check that the sanitizer runtimes shipped with g++/clang++ work
-# end-to-end against the system loader: compile each example with both
-# compilers, run it, and confirm the expected diagnostic is emitted.
-
-set -eo pipefail
-
-cpp_files_dir="${1:?usage: $0 <cpp_files_dir>}"
-
-case "$(uname -m)" in
-    x86_64) loader=/lib64/ld-linux-x86-64.so.2 ;;
-    aarch64) loader=/lib/ld-linux-aarch64.so.1 ;;
-    *)
-        echo "Unsupported arch: $(uname -m)" >&2
-        exit 1
-        ;;
-esac
-
-declare -A sanitize=(
-    [asan]="-fsanitize=address"
-    [tsan]="-fsanitize=thread"
-    [ubsan]="-fsanitize=undefined"
-)
-declare -A expect=(
-    [asan]="heap-use-after-free"
-    [tsan]="data race"
-    [ubsan]="signed integer overflow"
-)
-
-for compiler in g++ clang++; do
-    for name in asan tsan ubsan; do
-        bin="/tmp/${name}-${compiler}"
-        echo "=== Build ${name} with ${compiler} ==="
-        "$compiler" -std=c++20 -O1 -g ${sanitize[$name]} \
-            -Wl,--dynamic-linker=$loader \
-            "${cpp_files_dir}/${name}.cpp" -o "$bin"
-        echo "=== Run ${name}-${compiler} ==="
-        output=$("$bin" 2>&1) || true
-        echo "$output"
-        echo "$output" | grep -q "${expect[$name]}" ||
-            {
-                echo "expected '${expect[$name]}' from $bin"
-                exit 1
-            }
-        rm -f "$bin"
-    done
-done

docker/check-tools.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+# Verify that every tool expected in the Nix CI env is present and runnable.
+set -euo pipefail
+
+ccache --version
+clang --version
+clang++ --version
+clang-format --version
+cmake --version
+conan --version
+curl --version
+g++ --version
+gcc --version
+gcov --version
+gcovr --version
+git --version
+gpg --version
+less --version
+make --version
+mold --version
+netstat --version
+ninja --version
+perl --version
+pkg-config --version
+pre-commit --version
+python3 --version
+run-clang-tidy --help
+vim --version
+
+# A simple test to verify that git can clone a repository over HTTPS
+# (i.e. the CA bundle is wired up). Clone to a temp dir and clean up.
+tmp_clone="$(mktemp -d)"
+git clone --depth 1 https://github.com/XRPLF/actions.git "${tmp_clone}/actions"
+rm -rf "${tmp_clone}"

docker/install-sanitizer-libs.sh

@@ -0,0 +1,89 @@
+#!/bin/bash
+# Install sanitizer runtime libraries required to run binaries compiled with:
+#   -fsanitize=address   → libasan.so.8
+#   -fsanitize=thread    → libtsan.so.2
+#   -fsanitize=undefined → libubsan.so.1
+#
+# The exact SONAMEs required depend on the compiler toolchain used to build the
+# test binaries (see nix/ci-env.nix). If the toolchain is bumped and SONAMEs
+# change, update the list below (or detect them from the binaries).
+#
+# Supported base images:
+#   debian:bookworm
+#   ubuntu:20.04
+#   rhel:9
+#   nixos/nix        — tests are skipped; this script is not called
+
+set -euo pipefail
+
+if [ ! -f /etc/os-release ]; then
+    echo "ERROR: /etc/os-release not found; cannot detect OS" >&2
+    exit 1
+fi
+
+# shellcheck source=/dev/null
+. /etc/os-release
+
+echo "Detected OS: ${ID} ${VERSION_ID:-}"
+
+case "${ID}" in
+    debian)
+        apt-get update -y
+        apt-get install -y --no-install-recommends \
+            libasan8 \
+            libtsan2 \
+            libubsan1
+
+        apt-get clean
+        rm -rf /var/lib/apt/lists/*
+        ;;
+
+    ubuntu)
+        apt-get update -y
+        apt-get install -y --no-install-recommends \
+            gnupg \
+            software-properties-common
+        add-apt-repository -y ppa:ubuntu-toolchain-r/test
+        apt-get update -y
+        apt-get install -y --no-install-recommends \
+            libasan8 \
+            libtsan2 \
+            libubsan1
+
+        apt-get clean
+        rm -rf /var/lib/apt/lists/*
+        ;;
+
+    rhel | centos | rocky | almalinux)
+        dnf install -y \
+            libasan8 \
+            libtsan2 \
+            libubsan
+
+        dnf clean -y all
+        rm -rf /var/cache/dnf/*
+        ;;
+
+    *)
+        echo "ERROR: unsupported OS '${ID}'. Supported: debian, ubuntu, rhel-family" >&2
+        exit 1
+        ;;
+esac
+
+# Verify that every expected library is now resolvable by the dynamic linker.
+missing=0
+for lib in libasan.so.8 libtsan.so.2 libubsan.so.1; do
+    if ldconfig -p | grep -q "${lib}"; then
+        echo "OK: ${lib} found"
+    else
+        echo "ERROR: ${lib} not found after installation" >&2
+        missing=$((missing + 1))
+    fi
+done
+
+if [ "${missing}" -ne 0 ]; then
+    echo "ERROR: ${missing} library/libraries missing" >&2
+    exit 1
+fi
+
+echo "All sanitizer runtime libraries installed successfully."

docker/loader-path.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+case "$(uname -m)" in
+    x86_64) LOADER=/lib64/ld-linux-x86-64.so.2 ;;
+    aarch64) LOADER=/lib/ld-linux-aarch64.so.1 ;;
+    *)
+        echo "Unsupported arch: $(uname -m)" >&2
+        exit 1
+        ;;
+esac
+
+echo "${LOADER}"

docker/nix.Dockerfile

@@ -27,10 +27,12 @@ RUN mkdir /tmp/nix-store-closure && \
     cp -R $(nix-store -qR result/) /tmp/nix-store-closure
 
 # Final image
-FROM ${BASE_IMAGE}
+FROM ${BASE_IMAGE} AS final
+
+ARG BASE_IMAGE
 
 # bash is not located at /bin/bash in nixos/nix, so we need to create a symlink to it.
-RUN if [ -d /nix ]; then \
+RUN if echo "${BASE_IMAGE}" | grep -qiE 'nixos'; then \
         ln -s /root/.nix-profile/bin/bash /bin/bash; \
     fi
 
@@ -43,53 +45,70 @@ ENTRYPOINT ["/bin/bash"]
 COPY --from=builder /tmp/nix-store-closure /nix/store
 COPY --from=builder /tmp/build/result /nix/ci-env
 
-ENV PATH="/nix/ci-env/bin:$PATH"
+ENV PATH="/nix/ci-env/bin:${PATH}"
+
+# Point HTTPS clients (git, curl, conan, ...) at the CA bundle shipped in the
+# Nix CI environment, so TLS verification works without ca-certificates being
+# installed in the system.
+ENV SSL_CERT_FILE="/nix/ci-env/etc/ssl/certs/ca-bundle.crt"
+ENV GIT_SSL_CAINFO="/nix/ci-env/etc/ssl/certs/ca-bundle.crt"
 
 # Externally-built dynamically-linked ELF binaries hard-code the loader path
-# (e.g. /lib64/ld-linux-x86-64.so.2) in their PT_INTERP header. Copy the
-# loader from the Nix store to that path when the base image doesn't already
-# provide one (i.e. on nixos/nix).
+# (e.g. /lib64/ld-linux-x86-64.so.2) in their PT_INTERP header. Install it
+# from the Nix store when the base image doesn't already provide one.
+COPY docker/loader-path.sh /tmp/loader-path.sh
+
 RUN <<EOF
-case "$(uname -m)" in
-    x86_64)  target=/lib64/ld-linux-x86-64.so.2 ;;
-    aarch64) target=/lib/ld-linux-aarch64.so.1 ;;
-    *) echo "Unsupported arch: $(uname -m)" >&2; exit 1 ;;
-esac
-if [ ! -e "$target" ]; then
+target="$(/tmp/loader-path.sh)"
+
+if [ ! -e "${target}" ]; then
     # Use the loader from the same glibc that gcc links libc against, so
     # ld-linux and libc/libpthread share GLIBC_PRIVATE symbols at runtime.
-    src="$(dirname "$(gcc -print-file-name=libc.so.6)")/$(basename "$target")"
-    [ -e "$src" ] || { echo "ld-linux not found at $src" >&2; exit 1; }
-    mkdir -p "$(dirname "$target")"
-    cp "$src" "$target"
+    src="$(dirname "$(gcc -print-file-name=libc.so.6)")/$(basename "${target}")"
+    [ -e "${src}" ] || { echo "ld-linux not found at ${src}" >&2; exit 1; }
+    mkdir -p "$(dirname "${target}")"
+    cp "${src}" "${target}"
 fi
 EOF
 
+COPY docker/check-tools.sh /tmp/check-tools.sh
+RUN /tmp/check-tools.sh
+
+# Sanity-check that the g++/clang++ are able to build binaries, including sanitizer-instrumented ones.
+COPY docker/test_files/cpp_sources/ /tmp/cpp_sources/
+COPY docker/test_files/compile-cpp-sources.sh /tmp/compile-cpp-sources.sh
+RUN /tmp/compile-cpp-sources.sh /tmp/cpp_sources /tmp/bins
+
+# Tester: start from a clean BASE_IMAGE, install sanitizer runtime libraries,
+# and run the compiled test binaries to verify they execute correctly.
+FROM ${BASE_IMAGE} AS tester
+
+ARG BASE_IMAGE
+
+# bash is not located at /bin/bash in nixos/nix, so we need to create a symlink to it.
+RUN if echo "${BASE_IMAGE}" | grep -qiE 'nixos'; then \
+        ln -s /root/.nix-profile/bin/bash /bin/bash; \
+    fi
+
+SHELL ["/bin/bash", "-e", "-o", "pipefail", "-c"]
+
+# Sanity-check that the built binaries run correctly in the vanilla base image, with the necessary sanitizer runtime libraries installed.
+COPY docker/install-sanitizer-libs.sh /tmp/install-sanitizer-libs.sh
+COPY docker/test_files/run-test-binaries.sh /tmp/run-test-binaries.sh
+COPY --from=final /tmp/bins /tmp/bins
+
 RUN <<EOF
-ccache --version
-clang --version
-clang++ --version
-clang-format --version
-cmake --version
-conan --version
-g++ --version
-gcc --version
-gcovr --version
-git --version
-make --version
-mold --version
-ninja --version
-perl --version
-pkg-config --version
-pre-commit --version
-python3 --version
-run-clang-tidy --help
-vim --version
+if echo "${BASE_IMAGE}" | grep -qiE 'nixos'; then
+    echo "Skipping runnning binaries on NixOS."
+else
+    /tmp/install-sanitizer-libs.sh
+    /tmp/run-test-binaries.sh /tmp/bins
+fi
+touch /tmp/tests-passed
 EOF
 
-# Sanity-check that the sanitizer runtimes shipped with g++/clang++ work
-# end-to-end against the system loader.
-COPY docker/cpp_files/ /tmp/cpp_files/
-COPY docker/check-sanitizers.sh /tmp/check-sanitizers.sh
-
-RUN grep -qi ubuntu /etc/os-release 2>/dev/null && /tmp/check-sanitizers.sh /tmp/cpp_files || true
+# Output: the final image, gated on a successful test run in the tester stage.
+# Copying the sentinel from tester creates a hard build dependency: if the test
+# run above failed, this stage — and the overall build — fails too.
+FROM final
+COPY --from=tester /tmp/tests-passed /tmp/tests-passed

docker/test_files/compile-cpp-sources.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+# Compile all C++ test binaries during the Docker image build.
+# Each binary has the target system's ELF PT_INTERP (dynamic-linker path)
+# baked in so it can run on the (potentially minimal) final BASE_IMAGE.
+
+set -eo pipefail
+
+src_dir="${1:?usage: $0 <src_dir> <dst_dir>}"
+dst_dir="${2:?usage: $0 <src_dir> <dst_dir>}"
+
+loader="$(/tmp/loader-path.sh)"
+
+mkdir -p "${dst_dir}"
+
+function compile() {
+    local compiler="${1}"
+    local name="${2}"
+    local san_flag="${3:-}"
+
+    local src="${src_dir}/${name}.cpp"
+    local binary="${dst_dir}/${name}-${compiler}"
+
+    echo "=== Compiling ${name} with ${compiler} ==="
+    # Always statically link libstdc++ so the test binary does not depend on
+    # the host's libstdc++.so.6 version.
+    local compile_cmd="${compiler} -std=c++23 -O1 -g \
+        -pthread \
+        -static-libstdc++ \
+        ${san_flag} \
+        ${src} -o ${binary}"
+    echo "Compile cmd: ${compile_cmd}"
+    eval "${compile_cmd}"
+
+    echo "=== Patching ${binary} to use ${loader} as PT_INTERP ==="
+    local patch_cmd="patchelf --set-interpreter ${loader} --remove-rpath ${binary}"
+    echo "Patch cmd: ${patch_cmd}"
+    eval "${patch_cmd}"
+}
+
+declare -A sanitize=(
+    [regular]=""
+
+    [asan]="-fsanitize=address"
+    [tsan]="-fsanitize=thread"
+    [ubsan]="-fsanitize=undefined -fno-sanitize-recover=all"
+)
+
+for name in regular asan tsan ubsan; do
+    san_flag="${sanitize[${name}]}"
+    for compiler in g++ clang++; do
+        compile "${compiler}" "${name}" "${san_flag}"
+    done
+done
+
+echo "=== All binaries compiled ==="
+
+ls -la "${dst_dir}"

docker/test_files/cpp_sources/asan.cpp

@@ -2,6 +2,13 @@
 #include <cstddef>
 #include <iostream>
 
+// Regression test: the compiler-rt sanitizer interface headers must be on the
+// include path. A bare on-PATH clang in the Nix CI env doesn't get them
+// propagated automatically, so this include would fail to compile with clang++
+// if the env isn't wired up correctly. abseil hits the same include during
+// sanitizer builds. LeakSanitizer ships with AddressSanitizer.
+#include <sanitizer/lsan_interface.h>
+
 #if defined(__clang__) || defined(__GNUC__)
 __attribute__((noinline))
 #elif defined(_MSC_VER)

docker/test_files/cpp_sources/regular.cpp

@@ -0,0 +1,28 @@
+#include <iostream>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+static std::mutex gMutex;
+
+void
+worker(int id)
+{
+    std::lock_guard<std::mutex> lock(gMutex);
+    std::cout << "Hello from thread " << id << "\n";
+}
+
+int
+main()
+{
+    constexpr int kNumThreads = 10;
+    std::vector<std::thread> threads;
+    threads.reserve(kNumThreads);
+    for (int i = 0; i < kNumThreads; ++i)
+        threads.emplace_back(worker, i);
+    for (auto& t : threads)
+        t.join();
+
+    std::cout << "Hello from main thread\n";
+    return 0;
+}

docker/test_files/run-test-binaries.sh

@@ -0,0 +1,86 @@
+#!/bin/bash
+# Run pre-compiled sanitizer binaries and confirm each emits its expected diagnostic.
+# Binaries must already exist in <bins_dir> with the layout:
+# <name>-g++ and <name>-clang++ for name in {regular,asan,tsan,ubsan}
+
+set -eo pipefail
+
+bins_dir="${1:?usage: $0 <bins_dir>}"
+
+failed_binaries=()
+
+# Run a binary and verify its exit code and output.
+# Usage: run <binary> <expected_output> <expected_rc>
+function run() {
+    local binary="${1}"
+    local expected_output="${2}"
+    local expected_rc="${3}"
+
+    local out_file
+    out_file="$(mktemp)"
+
+    echo "=== Run ${binary} ==="
+    set +e
+    "${binary}" >"${out_file}" 2>&1
+    local rc=$?
+    set -e
+
+    cat "${out_file}"
+
+    local failed=0
+    if [ "${expected_rc}" = "nonzero" ]; then
+        if [ "${rc}" -eq 0 ]; then
+            echo "ERROR: expected non-zero exit code from ${binary}, got ${rc}" >&2
+            failed=1
+        fi
+    elif [ "${rc}" -ne "${expected_rc}" ]; then
+        echo "ERROR: expected exit code ${expected_rc} from ${binary}, got ${rc}" >&2
+        failed=1
+    fi
+
+    if ! grep -q "${expected_output}" "${out_file}"; then
+        echo "ERROR: expected '${expected_output}' from ${binary}" >&2
+        failed=1
+    fi
+
+    if [ "${failed}" -eq 0 ]; then
+        echo "OK: '${expected_output}' detected"
+    else
+        failed_binaries+=("${binary}")
+    fi
+}
+
+declare -A expect=(
+    [regular]="Hello from main thread"
+
+    [asan]="heap-use-after-free"
+    [tsan]="data race"
+    [ubsan]="signed integer overflow"
+)
+
+for compiler in g++ clang++; do
+    for name in regular asan tsan ubsan; do
+        binary="${bins_dir}/${name}-${compiler}"
+
+        if [ "${name}" = "tsan" ] && [ "${compiler}" = "g++" ] &&
+            grep -qi 'debian' /etc/os-release 2>/dev/null &&
+            [ "$(uname -m)" = "aarch64" ]; then
+            echo "=== Skipping ${binary} (tsan-g++ unsupported on Debian ARM64) ==="
+            echo "    NOTE: to enable it, add --security-opt seccomp=unconfined to your docker run command"
+            continue
+        fi
+
+        if [ "${name}" = "regular" ]; then
+            expected_rc=0
+        else
+            expected_rc=nonzero
+        fi
+        run "${binary}" "${expect[$name]}" "${expected_rc}"
+    done
+done
+
+if [ "${#failed_binaries[@]}" -gt 0 ]; then
+    echo "ERROR: the following binaries failed:" >&2
+    printf '  %s\n' "${failed_binaries[@]}" >&2
+    exit 1
+fi

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1777954456,
-        "narHash": "sha256-hGdgeU2Nk87RAuZyYjyDjFL6LK7dAZN5RE9+hrDTkDU=",
+        "lastModified": 1780243769,
+        "narHash": "sha256-x5UQuRsH3MqI0U9afaXSNqzTPSeZlRLvFAav2Ux1pNw=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "549bd84d6279f9852cae6225e372cc67fb91a4c1",
+        "rev": "331800de5053fcebacf6813adb5db9c9dca22a0c",
         "type": "github"
       },
       "original": {

include/xrpl/basics/Number.h

@@ -2,12 +2,14 @@
 
 #include <xrpl/beast/utility/instrumentation.h>
 
+#include <array>
 #include <cstdint>
 #include <functional>
 #include <limits>
 #include <optional>
 #include <ostream>
 #include <set>
+#include <stdexcept>
 #include <string>
 #include <unordered_map>
 
@@ -40,6 +42,47 @@ isPowerOfTen(T value)
     return logTen(value).has_value();
 }
 
+namespace detail {
+
+/** Builds a table of the powers of 10
+ *
+ * This function is marked consteval, so it can only be run in
+ * a constexpr context. This assures that it is and can only be run at
+ * compile time. Doing it at runtime would be pretty wasteful and
+ * inefficient.
+ */
+constexpr std::size_t kInt64Digits = 20;
+consteval std::array<std::uint64_t, kInt64Digits>
+buildPowersOfTen()
+{
+    std::array<std::uint64_t, kInt64Digits> result{};
+
+    std::uint64_t power = 1;
+    std::size_t exponent = 0;
+    // end the loop early so it doesn't overflow;
+    for (; exponent < result.size() - 1; ++exponent, power *= 10)
+    {
+        result[exponent] = power;
+        if (power > std::numeric_limits<std::uint64_t>::max() / 10)
+            throw std::logic_error("Power of 10 table is too big");
+    }
+    result[exponent] = power;
+    if (power < std::numeric_limits<std::uint64_t>::max() / 10)
+        throw std::logic_error("Power of 10 table is not big enough for the uint64_t type");
+
+    return result;
+}
+
+}  // namespace detail
+
+constexpr std::array<std::uint64_t, detail::kInt64Digits> kPowerOfTen = detail::buildPowersOfTen();
+
+static_assert(kPowerOfTen[0] == 1);
+static_assert(kPowerOfTen[1] == 10);
+static_assert(kPowerOfTen[10] == 10'000'000'000);
+static_assert(
+    isPowerOfTen(kPowerOfTen.back()) && *logTen(kPowerOfTen.back()) == detail::kInt64Digits - 1);
+
 /** MantissaRange defines a range for the mantissa of a normalized Number.
  *
  * The mantissa is in the range [min, max], where
@@ -76,6 +119,7 @@ isPowerOfTen(T value)
 struct MantissaRange final
 {
     using rep = std::uint64_t;
+
     enum class MantissaScale {
         Small,
         // LargeLegacy can be removed when fixCleanup3_2_0 is retired
@@ -89,19 +133,15 @@ struct MantissaRange final
         Enabled = true,
     };
 
-    explicit constexpr MantissaRange(MantissaScale scale)
-        : min(getMin(scale))
-        , cuspRoundingFixEnabled(isCuspFixEnabled(scale))
-        , log(logTen(min).value_or(-1))
-        , scale(scale)
+    explicit constexpr MantissaRange(MantissaScale sc) : scale(sc)
     {
     }
 
-    rep min;
-    rep max{(min * 10) - 1};
-    CuspRoundingFix cuspRoundingFixEnabled;
-    int log;
-    MantissaScale scale;
+    MantissaScale const scale;
+    int const log{getExponent(scale)};
+    rep const min{getMin(scale, log)};
+    rep const max{(min * 10) - 1};
+    CuspRoundingFix const cuspRoundingFixEnabled{isCuspFixEnabled(scale)};
 
     static MantissaRange const&
     getMantissaRange(MantissaScale scale);
@@ -110,23 +150,35 @@ struct MantissaRange final
     getAllScales();
 
 private:
-    static constexpr rep
-    getMin(MantissaScale scale)
+    static constexpr int
+    getExponent(MantissaScale scale)
     {
         switch (scale)
         {
             case MantissaScale::Small:
-                return 1'000'000'000'000'000ULL;
+                return 15;
             case MantissaScale::LargeLegacy:
             case MantissaScale::Large:
-                return 1'000'000'000'000'000'000ULL;
+                return 18;
+            // LCOV_EXCL_START
             default:
                 // If called in a constexpr context, this throw assures that the build fails if an
                 // invalid scale is used.
-                throw std::runtime_error("Unknown mantissa scale");  // LCOV_EXCL_LINE
+                throw std::runtime_error("Unknown mantissa scale");
+                // LCOV_EXCL_STOP
         }
     }
 
+    // Keep this function for future use with different ways to compute
+    // the ranges.
+    static constexpr rep
+    getMin(MantissaScale scale, int exponent)
+    {
+        if (exponent < 0 || exponent >= kPowerOfTen.size())
+            throw std::runtime_error("Invalid exponent");  // LCOV_EXCL_LINE
+        return kPowerOfTen[exponent];
+    }
+
     static constexpr CuspRoundingFix
     isCuspFixEnabled(MantissaScale scale)
     {
@@ -477,8 +529,7 @@ public:
     template <
         auto MinMantissa,
         auto MaxMantissa,
-        Integral64 T = std::decay_t<decltype(MinMantissa)>,
-        Integral64 TMax = std::decay_t<decltype(MaxMantissa)>>
+        Integral64 T = std::decay_t<decltype(MinMantissa)>>
     [[nodiscard]]
     std::pair<T, int>
     normalizeToRange() const;
@@ -519,7 +570,8 @@ private:
         int& exponent,
         MantissaRange::rep const& minMantissa,
         MantissaRange::rep const& maxMantissa,
-        MantissaRange::CuspRoundingFix cuspRoundingFixEnabled);
+        MantissaRange::CuspRoundingFix cuspRoundingFixEnabled,
+        bool dropped);
 
     [[nodiscard]] bool
     isnormal() const noexcept;
@@ -725,16 +777,18 @@ Number::isnormal() const noexcept
          kMinExponent <= exponent_ && exponent_ <= kMaxExponent);
 }
 
-template <auto MinMantissa, auto MaxMantissa, Integral64 T, Integral64 TMax>
+template <auto MinMantissa, auto MaxMantissa, Integral64 T>
 std::pair<T, int>
 Number::normalizeToRange() const
 {
     static_assert(std::is_same_v<T, std::uint64_t> || std::is_same_v<T, std::int64_t>);
-    static_assert(std::is_same_v<T, TMax>);
+    static_assert(std::is_same_v<T, std::decay_t<decltype(MinMantissa)>>);
+    static_assert(std::is_same_v<T, std::decay_t<decltype(MaxMantissa)>>);
     auto constexpr kMIN = static_cast<T>(MinMantissa);
     auto constexpr kMAX = static_cast<T>(MaxMantissa);
     static_assert(kMIN > 0);
     static_assert(kMIN % 10 == 0);
+    static_assert(isPowerOfTen(kMIN));
     static_assert(kMAX % 10 == 9);
     static_assert((kMAX + 1) / 10 == kMIN);
 

include/xrpl/basics/TaggedCache.h

@@ -157,7 +157,7 @@ public:
     /** Fetch an item from the cache.
         If the digest was not found, Handler
         will be called with this signature:
-            std::shared_ptr<SLE const>(void)
+            SLE::const_pointer(void)
     */
     template <class Handler>
     SharedPointerType

include/xrpl/ledger/ApplyView.h

@@ -123,7 +123,7 @@ private:
         bool preserveOrder,
         Keylet const& directory,
         uint256 const& key,
-        std::function<void(std::shared_ptr<SLE> const&)> const& describe);
+        std::function<void(SLE::ref)> const& describe);
 
 public:
     ApplyView() = default;
@@ -153,7 +153,7 @@ public:
 
         @return `nullptr` if the key is not present
     */
-    virtual std::shared_ptr<SLE>
+    virtual SLE::pointer
     peek(Keylet const& k) = 0;
 
     /** Remove a peeked SLE.
@@ -168,7 +168,7 @@ public:
             The key is no longer associated with the SLE.
     */
     virtual void
-    erase(std::shared_ptr<SLE> const& sle) = 0;
+    erase(SLE::ref sle) = 0;
 
     /** Insert a new state SLE
 
@@ -189,7 +189,7 @@ public:
         @note The key is taken from the SLE
     */
     virtual void
-    insert(std::shared_ptr<SLE> const& sle) = 0;
+    insert(SLE::ref sle) = 0;
 
     /** Indicate changes to a peeked SLE
 
@@ -208,7 +208,7 @@ public:
     */
     /** @{ */
     virtual void
-    update(std::shared_ptr<SLE> const& sle) = 0;
+    update(SLE::ref sle) = 0;
 
     //--------------------------------------------------------------------------
 
@@ -301,7 +301,7 @@ public:
     dirAppend(
         Keylet const& directory,
         Keylet const& key,
-        std::function<void(std::shared_ptr<SLE> const&)> const& describe)
+        std::function<void(SLE::ref)> const& describe)
     {
         if (key.type != ltOFFER)
         {
@@ -340,7 +340,7 @@ public:
     dirInsert(
         Keylet const& directory,
         uint256 const& key,
-        std::function<void(std::shared_ptr<SLE> const&)> const& describe)
+        std::function<void(SLE::ref)> const& describe)
     {
         return dirAdd(false, directory, key, describe);
     }
@@ -349,7 +349,7 @@ public:
     dirInsert(
         Keylet const& directory,
         Keylet const& key,
-        std::function<void(std::shared_ptr<SLE> const&)> const& describe)
+        std::function<void(SLE::ref)> const& describe)
     {
         return dirAdd(false, directory, key.key, describe);
     }
@@ -411,7 +411,7 @@ createRoot(
     ApplyView& view,
     Keylet const& directory,
     uint256 const& key,
-    std::function<void(std::shared_ptr<SLE> const&)> const& describe);
+    std::function<void(SLE::ref)> const& describe);
 
 auto
 findPreviousPage(ApplyView& view, Keylet const& directory, SLE::ref start);
@@ -434,7 +434,7 @@ insertPage(
     SLE::ref next,
     uint256 const& key,
     Keylet const& directory,
-    std::function<void(std::shared_ptr<SLE> const&)> const& describe);
+    std::function<void(SLE::ref)> const& describe);
 
 }  // namespace directory
 }  // namespace xrpl

include/xrpl/ledger/ApplyViewImpl.h

@@ -67,8 +67,8 @@ public:
         std::function<void(
             uint256 const& key,
             bool isDelete,
-            std::shared_ptr<SLE const> const& before,
-            std::shared_ptr<SLE const> const& after)> const& func);
+            SLE::const_ref before,
+            SLE::const_ref after)> const& func);
 
 private:
     std::optional<STAmount> deliver_;

include/xrpl/ledger/BookDirs.h

@@ -11,13 +11,13 @@ private:
     uint256 const root_;
     uint256 const nextQuality_;
     uint256 const key_;
-    std::shared_ptr<SLE const> sle_ = nullptr;
+    SLE::const_pointer sle_ = nullptr;
     unsigned int entry_ = 0;
     uint256 index_;
 
 public:
     class const_iterator;  // NOLINT(readability-identifier-naming)
-    using value_type = std::shared_ptr<SLE const>;
+    using value_type = SLE::const_pointer;
 
     BookDirs(ReadView const&, Book const&);
 
@@ -76,7 +76,7 @@ private:
     uint256 nextQuality_;
     uint256 key_;
     uint256 curKey_;
-    std::shared_ptr<SLE const> sle_;
+    SLE::const_pointer sle_;
     unsigned int entry_ = 0;
     uint256 index_;
     std::optional<value_type> mutable cache_;

include/xrpl/ledger/CachedView.h

@@ -36,7 +36,7 @@ public:
     bool
     exists(Keylet const& k) const override;
 
-    std::shared_ptr<SLE const>
+    SLE::const_pointer
     read(Keylet const& k) const override;
 
     bool

include/xrpl/ledger/Dir.h

@@ -22,12 +22,12 @@ class Dir
 private:
     ReadView const* view_ = nullptr;
     Keylet root_;
-    std::shared_ptr<SLE const> sle_;
+    SLE::const_pointer sle_;
     STVector256 const* indexes_ = nullptr;
 
 public:
     class ConstIterator;
-    using value_type = std::shared_ptr<SLE const>;
+    using value_type = SLE::const_pointer;
 
     Dir(ReadView const&, Keylet const&);
 
@@ -102,7 +102,7 @@ private:
     Keylet page_;
     uint256 index_;
     std::optional<value_type> mutable cache_;
-    std::shared_ptr<SLE const> sle_;
+    SLE::const_pointer sle_;
     STVector256 const* indexes_ = nullptr;
     std::vector<uint256>::const_iterator it_;
 };

include/xrpl/ledger/Ledger.h

@@ -166,7 +166,7 @@ public:
     std::optional<uint256>
     succ(uint256 const& key, std::optional<uint256> const& last = std::nullopt) const override;
 
-    std::shared_ptr<SLE const>
+    SLE::const_pointer
     read(Keylet const& k) const override;
 
     std::unique_ptr<SlesType::iter_base>
@@ -202,16 +202,16 @@ public:
     //
 
     void
-    rawErase(std::shared_ptr<SLE> const& sle) override;
+    rawErase(SLE::ref sle) override;
 
     void
-    rawInsert(std::shared_ptr<SLE> const& sle) override;
+    rawInsert(SLE::ref sle) override;
 
     void
     rawErase(uint256 const& key);
 
     void
-    rawReplace(std::shared_ptr<SLE> const& sle) override;
+    rawReplace(SLE::ref sle) override;
 
     void
     rawDestroyXRP(XRPAmount const& fee) override
@@ -361,7 +361,7 @@ public:
     bool
     isVotingLedger() const;
 
-    std::shared_ptr<SLE>
+    SLE::pointer
     peek(Keylet const& k) const;
 
 private:

include/xrpl/ledger/OpenView.h

@@ -1,9 +1,7 @@
 #pragma once
 
-#include <xrpl/ledger/OrderBookIndex.h>
 #include <xrpl/ledger/RawView.h>
 #include <xrpl/ledger/ReadView.h>
-#include <xrpl/ledger/TopOfBookCache.h>
 #include <xrpl/ledger/detail/RawStateTable.h>
 #include <xrpl/protocol/STArray.h>
 #include <xrpl/protocol/XRPAmount.h>
@@ -91,17 +89,6 @@ private:
 
     bool open_ = true;
 
-    // Per-view top-of-book cache. Lifetime is the view's lifetime; on
-    // OpenView copy (used to snapshot for parallel apply / batch views),
-    // the underlying data is copied but counters reset.
-    mutable TopOfBookCache topOfBookCache_;
-
-    // Per-view ordered order-book index (Plan 9). Generalizes the cache from
-    // "best page" to the full quality-ordered offer sequence, letting the
-    // crossing path iterate via an in-memory cursor instead of re-walking the
-    // SHAMap with succ() per offer. Maintained off the same notifications.
-    mutable OrderBookIndex orderBookIndex_;
-
 public:
     OpenView() = delete;
     OpenView&
@@ -210,49 +197,9 @@ public:
     std::optional<key_type>
     succ(key_type const& key, std::optional<key_type> const& last = std::nullopt) const override;
 
-    std::shared_ptr<SLE const>
+    SLE::const_pointer
     read(Keylet const& k) const override;
 
-    // Top-of-book cache hooks
-
-    [[nodiscard]] std::optional<uint256>
-    topOfBookFirstPage(Book const& book) const override;
-
-    void
-    recordTopOfBook(Book const& book, uint256 const& firstPageKey) const override;
-
-    void
-    notifyOfferInserted(Book const& book, uint256 const& dirKey, uint256 const& offerKey)
-        const override;
-
-    void
-    notifyOfferDeleted(Book const& book, uint256 const& dirKey, uint256 const& offerKey)
-        const override;
-
-    [[nodiscard]] std::optional<std::vector<uint256>>
-    orderedBook(Book const& book) const override;
-
-    [[nodiscard]] TopOfBookCache const&
-    topOfBookCache() const noexcept
-    {
-        return topOfBookCache_;
-    }
-
-    [[nodiscard]] OrderBookIndex const&
-    orderBookIndex() const noexcept
-    {
-        return orderBookIndex_;
-    }
-
-    // Non-const access for seeding (rebuild-from-state at attach time) and for
-    // the cursor's lazy populate. The index is auxiliary, so this never affects
-    // the authoritative state.
-    [[nodiscard]] OrderBookIndex&
-    orderBookIndex() noexcept
-    {
-        return orderBookIndex_;
-    }
-
     std::unique_ptr<SlesType::iter_base>
     slesBegin() const override;
 
@@ -277,13 +224,13 @@ public:
     // RawView
 
     void
-    rawErase(std::shared_ptr<SLE> const& sle) override;
+    rawErase(SLE::ref sle) override;
 
     void
-    rawInsert(std::shared_ptr<SLE> const& sle) override;
+    rawInsert(SLE::ref sle) override;
 
     void
-    rawReplace(std::shared_ptr<SLE> const& sle) override;
+    rawReplace(SLE::ref sle) override;
 
     void
     rawDestroyXRP(XRPAmount const& fee) override;

include/xrpl/ledger/OrderBookIndex.h

@@ -1,181 +0,0 @@
-#pragma once
-
-#include <xrpl/basics/base_uint.h>
-#include <xrpl/ledger/detail/PersistentOrderTree.h>
-#include <xrpl/protocol/Book.h>
-
-#include <atomic>
-#include <cstddef>
-#include <cstdint>
-#include <optional>
-#include <shared_mutex>
-#include <unordered_map>
-#include <utility>
-#include <vector>
-
-namespace xrpl {
-
-class ReadView;
-
-/** Deterministic, ordered, **persistent** in-memory index of every active order
-    book.
-
-    `BookTip::step()` finds the next offer to cross by calling `ReadView::succ()`
-    — an O(log N) SHAMap successor walk from the book root, re-done once per
-    consumed offer. Profiling shows that walk is ~32% of crossing-apply cost.
-    This index materializes the same quality-ordered offer sequence so iteration
-    becomes an in-memory cursor advance instead of a trie re-walk.
-
-    It generalizes `TopOfBookCache` from "the best directory page" to "the full
-    ordered book". Like `FlatStateMap`, it is **auxiliary**: the SHAMap remains
-    the authoritative state and the source of the consensus root. The index is
-    rebuildable from the SHAMap at any time (`rebuildBook`) and differentially
-    validated against it (`validateMatchesShaMap`); a divergence is a bug in the
-    maintenance hooks, never a fallback.
-
-    **Persistence.** Each book's offers live in an immutable, structurally-shared
-    weight-balanced tree ([[detail/PersistentOrderTree.h]]). `clone()` copies only
-    the per-book `shared_ptr` roots (O(#books)), not the offers — so the
-    open-ledger copy-on-write (`OpenView` copy per `modify()`) preserves the index
-    cheaply and it stays warm across transactions, instead of cold-starting and
-    rebuilding per tx. Immutable nodes also make the COW rollback of a discarded
-    sandbox free: it simply drops its own root pointers.
-
-    Ordering invariant (the load-bearing property for bit-exact crossing):
-
-      - Books are keyed by `Book` (which already carries the permissioned-DEX
-        `domain`), so each book — open or domain — is indexed independently.
-      - Within a book, the tree is keyed by `(dirRoot, insertSeq)`. `dirRoot` is
-        the quality-directory root key; ascending == best-quality-first ==
-        `succ()` order. `insertSeq` is a per-book monotonic counter capturing
-        directory append order; since `dirRemove` preserves relative order and
-        offer keys are never reused, in-order traversal reproduces the SHAMap
-        directory walk byte-for-byte.
-
-    Maintenance drives `insertOffer`/`deleteOffer` from the offer-mutation
-    notifications (`notifyOfferInserted`/`notifyOfferDeleted`), which fire with
-    the quality-directory root key and the offer key.
-*/
-class OrderBookIndex
-{
-public:
-    OrderBookIndex() = default;
-
-    /** Move-construct by locking the source and stealing its book map.
-        Counters are not transferred (a fresh view starts its own accounting). */
-    OrderBookIndex(OrderBookIndex&& other);
-
-    OrderBookIndex(OrderBookIndex const&) = delete;
-    OrderBookIndex&
-    operator=(OrderBookIndex const&) = delete;
-    OrderBookIndex&
-    operator=(OrderBookIndex&&) = delete;
-
-    /** Cheap structural copy: clones the per-book tree roots (O(#books)
-        shared_ptr copies), sharing all offer nodes. Used by the `OpenView` copy
-        ctor so the index stays warm across the open-ledger COW. Counters reset. */
-    [[nodiscard]] OrderBookIndex
-    clone() const;
-
-    // --- maintenance (apply-path hooks) ---
-
-    /** Record that `offerKey` was inserted into `book` at quality-directory root
-        `dirRoot`. Appended (next insertSeq) so it sorts after same-level offers,
-        preserving directory order. */
-    void
-    insertOffer(Book const& book, uint256 const& dirRoot, uint256 const& offerKey);
-
-    /** Record that `offerKey` was removed from `book` at quality-directory root
-        `dirRoot`. The book is dropped when it empties. Removing an absent key is
-        a no-op. */
-    void
-    deleteOffer(Book const& book, uint256 const& dirRoot, uint256 const& offerKey);
-
-    // --- ordered read access (BookTip seam) ---
-
-    /** All offer keys of `book`, best-quality-first, directory order within a
-        level. Empty if the book is absent. */
-    [[nodiscard]] std::vector<uint256>
-    flatten(Book const& book) const;
-
-    /** The best (first) offer key of `book`, or nullopt if absent. */
-    [[nodiscard]] std::optional<uint256>
-    firstOffer(Book const& book) const;
-
-    // --- rebuild / validation (composition with the authoritative SHAMap) ---
-
-    /** Repopulate `book` from `view` by the canonical quality-ordered walk
-        (`succ()` over directory roots + directory iteration within each). */
-    void
-    rebuildBook(ReadView const& view, Book const& book);
-
-    /** True iff the maintained sequence for `book` equals a fresh walk of
-        `view`. The differential invariant. */
-    [[nodiscard]] bool
-    validateMatchesShaMap(ReadView const& view, Book const& book) const;
-
-    // --- bookkeeping ---
-
-    /** True if `book` has an entry (at least one offer). O(1). Present implies
-        non-empty (empty books are dropped). */
-    [[nodiscard]] bool
-    contains(Book const& book) const;
-
-    void
-    eraseBook(Book const& book);
-
-    void
-    clear();
-
-    [[nodiscard]] std::size_t
-    bookCount() const;
-
-    [[nodiscard]] std::size_t
-    offerCount(Book const& book) const;
-
-    [[nodiscard]] std::uint64_t
-    inserts() const noexcept
-    {
-        return inserts_.load(std::memory_order_relaxed);
-    }
-
-    [[nodiscard]] std::uint64_t
-    deletes() const noexcept
-    {
-        return deletes_.load(std::memory_order_relaxed);
-    }
-
-    [[nodiscard]] std::uint64_t
-    rebuilds() const noexcept
-    {
-        return rebuilds_.load(std::memory_order_relaxed);
-    }
-
-    // --- operator-facing kill switch (mirrors TopOfBookCache) ---
-
-    [[nodiscard]] static bool
-    enabled() noexcept;
-
-    static void
-    setEnabled(bool on) noexcept;
-
-private:
-    struct BookState
-    {
-        detail::OrderTreePtr root;  // persistent (dirRoot, insertSeq) -> offerKey
-        std::uint64_t nextSeq{0};   // per-book monotonic append counter
-    };
-
-    // Canonical quality-ordered walk of `book` in `view`: (dirRoot, offerKey)
-    // for each offer, best-quality-first, directory order within a level.
-    [[nodiscard]] static std::vector<std::pair<uint256, uint256>>
-    walkBook(ReadView const& view, Book const& book);
-
-    mutable std::shared_mutex mutex_;
-    std::unordered_map<Book, BookState> books_;
-    std::atomic<std::uint64_t> inserts_{0};
-    std::atomic<std::uint64_t> deletes_{0};
-    std::atomic<std::uint64_t> rebuilds_{0};
-};
-
-}  // namespace xrpl

include/xrpl/ledger/RawView.h

@@ -25,7 +25,7 @@ public:
         can calculate metadata.
     */
     virtual void
-    rawErase(std::shared_ptr<SLE> const& sle) = 0;
+    rawErase(SLE::ref sle) = 0;
 
     /** Unconditionally insert a state item.
 
@@ -39,7 +39,7 @@ public:
         @note The key is taken from the SLE
     */
     virtual void
-    rawInsert(std::shared_ptr<SLE> const& sle) = 0;
+    rawInsert(SLE::ref sle) = 0;
 
     /** Unconditionally replace a state item.
 
@@ -54,7 +54,7 @@ public:
         @note The key is taken from the SLE
     */
     virtual void
-    rawReplace(std::shared_ptr<SLE> const& sle) = 0;
+    rawReplace(SLE::ref sle) = 0;
 
     /** Destroy XRP.
 

include/xrpl/ledger/ReadView.h

@@ -3,7 +3,6 @@
 #include <xrpl/basics/chrono.h>
 #include <xrpl/beast/hash/uhash.h>
 #include <xrpl/ledger/detail/ReadViewFwdRange.h>
-#include <xrpl/protocol/Book.h>
 #include <xrpl/protocol/Fees.h>
 #include <xrpl/protocol/IOUAmount.h>
 #include <xrpl/protocol/Indexes.h>
@@ -17,7 +16,6 @@
 #include <cstdint>
 #include <optional>
 #include <unordered_set>
-#include <vector>
 
 namespace xrpl {
 
@@ -36,9 +34,9 @@ public:
 
     using key_type = uint256;
 
-    using mapped_type = std::shared_ptr<SLE const>;
+    using mapped_type = SLE::const_pointer;
 
-    struct SlesType : detail::ReadViewFwdRange<std::shared_ptr<SLE const>>
+    struct SlesType : detail::ReadViewFwdRange<SLE::const_pointer>
     {
         explicit SlesType(ReadView const& view);
         [[nodiscard]] Iterator
@@ -145,7 +143,7 @@ public:
         @return `nullptr` if the key is not present or
                 if the type does not match.
     */
-    [[nodiscard]] virtual std::shared_ptr<SLE const>
+    [[nodiscard]] virtual SLE::const_pointer
     read(Keylet const& k) const = 0;
 
     // Accounts in a payment are not allowed to use assets acquired during that
@@ -190,68 +188,6 @@ public:
         return count;
     }
 
-    //
-    // Top-of-book cache hooks
-    //
-    // The default implementations make every non-overriding view a no-op
-    // pass-through, so non-orderbook code is unaffected. OpenView overrides
-    // these to maintain a real `TopOfBookCache`; views that wrap a base
-    // (ApplyViewBase, PaymentSandbox, ...) delegate to that base.
-
-    /** Return the cached keylet of the best (lowest-keyed) directory page
-        for `book`, if known. std::nullopt forces a `succ()` fallback.
-    */
-    [[nodiscard]] virtual std::optional<uint256>
-    topOfBookFirstPage(Book const& book) const
-    {
-        return std::nullopt;
-    }
-
-    /** Populate the cache after a `succ()`-driven discovery. Called from
-        the cold path of `BookTip::step()`.
-    */
-    virtual void
-    recordTopOfBook(Book const& book, uint256 const& firstPageKey) const
-    {
-    }
-
-    /** Apply-path notification: an offer was inserted into `book` at
-        directory keylet `dirKey`. The cache may use this to update or
-        invalidate its entry; the call must be safe under any base view.
-    */
-    virtual void
-    notifyOfferInserted(Book const& book, uint256 const& dirKey, uint256 const& offerKey) const
-    {
-    }
-
-    /** Apply-path notification: an offer was deleted from `book` at
-        directory keylet `dirKey`. If the deleted offer was on the
-        cached top page, the cache invalidates that entry.
-
-        `offerKey` is the deleted offer's ledger key — unused by the cache,
-        consumed by the order-book index.
-    */
-    virtual void
-    notifyOfferDeleted(Book const& book, uint256 const& dirKey, uint256 const& offerKey) const
-    {
-    }
-
-    /** Return `book`'s offer keys best-quality-first (the order the crossing
-        path consumes them), or std::nullopt to force the `succ()`-based walk.
-
-        Lets `BookTip` iterate the book from an in-memory cursor instead of
-        re-walking the SHAMap with `succ()` per offer. A returned vector is
-        guaranteed complete for `book` — implementations rebuild from the
-        authoritative state on a miss, so the cursor can never under-include.
-        Empty/absent books return nullopt (the cheap `succ()` path finds
-        nothing). Default: no index, always nullopt.
-    */
-    [[nodiscard]] virtual std::optional<std::vector<uint256>>
-    orderedBook(Book const& book) const
-    {
-        return std::nullopt;
-    }
-
     // used by the implementation
     [[nodiscard]] virtual std::unique_ptr<SlesType::iter_base>
     slesBegin() const = 0;

include/xrpl/ledger/Sandbox.h

@@ -35,7 +35,6 @@ public:
     apply(RawView& to)
     {
         items_.apply(to);
-        flushTopOfBookNotifications();
     }
 };
 

include/xrpl/ledger/TopOfBookCache.h

@@ -1,163 +0,0 @@
-#pragma once
-
-#include <xrpl/basics/base_uint.h>
-#include <xrpl/protocol/Book.h>
-#include <xrpl/protocol/Protocol.h>
-
-#include <atomic>
-#include <cstdint>
-#include <mutex>
-#include <optional>
-#include <unordered_map>
-
-namespace xrpl {
-
-/** One entry in the top-of-book cache.
-
-    Records the keylet of the best-quality (lowest-keyed) directory page
-    for a single order book at the time the entry was recorded.
-*/
-struct TopOfBookEntry
-{
-    /// Keylet of the best directory page for the book.
-    uint256 firstPageKey;
-    /// Quality bits encoded in firstPageKey (decoded for fast comparison).
-    std::uint64_t bestQuality{0};
-    /// Ledger sequence at which this entry was populated.
-    LedgerIndex asOfLedger{0};
-};
-
-/** Cache of "best directory page" keylet per active order book.
-
-    Reads of the top of an order book usually return the same directory page
-    over and over, but `BookTip::step()` re-walks the SHAMap on every call.
-    This cache memoizes that result. Lookups become a single hash-map probe;
-    the SHAMap successor walk happens only on cold or invalidated entries.
-
-    The cache is auxiliary — invalidating an entry is always safe, since the
-    next read repopulates lazily via `ReadView::succ()`. That property is what
-    lets the cache ship without an amendment.
-
-    Maintenance rules, applied at the apply path:
-
-    - **Offer inserted**: if the new offer's directory keylet is at-or-better
-      than the cached top, update the entry. Otherwise no-op.
-    - **Offer deleted**: if the deleted offer was on the cached top page,
-      invalidate. Otherwise no-op.
-
-    A best-page key is `keylet::quality(keylet::kBook(book), rate).key`. All
-    pages of a single book share the same prefix, so lower uint256 key =
-    better quality. Comparisons in this file rely on that ordering.
-*/
-class TopOfBookCache
-{
-public:
-    TopOfBookCache() = default;
-
-    /** Copy-construct (used when snapshotting open->closed ledger).
-
-        Hit/miss/invalidation counters are not copied; only the data is.
-    */
-    TopOfBookCache(TopOfBookCache const& other);
-
-    /** Move-construct by locking the source and stealing its map.
-
-        Needed because views that own a cache (OpenView) are moveable;
-        std::mutex is not, so the move is implemented via lock-and-move.
-        Counters are not transferred.
-    */
-    TopOfBookCache(TopOfBookCache&& other);
-
-    TopOfBookCache&
-    operator=(TopOfBookCache const&) = delete;
-    TopOfBookCache&
-    operator=(TopOfBookCache&&) = delete;
-
-    /** Look up the cached top of `book`.
-
-        Returns std::nullopt on miss. Hit/miss counters are updated.
-    */
-    [[nodiscard]] std::optional<TopOfBookEntry>
-    get(Book const& book) const;
-
-    /** Record (or overwrite) a top-of-book entry for `book`.
-
-        Called from the cold path after `succ()` discovers the first page.
-    */
-    void
-    record(Book const& book, uint256 const& firstPageKey, LedgerIndex seq);
-
-    /** Notify the cache that an offer was inserted into `book` at directory
-        keylet `dirKey`.
-
-        If the new keylet is better than (less than) the cached top, the entry
-        is updated. If it is equal, no change. If worse, no change.
-
-        If no entry exists for `book`, this is a no-op: the next read will
-        populate from `succ()`.
-    */
-    void
-    onOfferInsert(Book const& book, uint256 const& dirKey, LedgerIndex seq);
-
-    /** Notify the cache that an offer was deleted from `book` at directory
-        keylet `dirKey`.
-
-        If the delete was on the cached top page, invalidate (the page may
-        now be empty, or the offer count is irrelevant — next read repopulates).
-        Otherwise no-op.
-    */
-    void
-    onOfferDelete(Book const& book, uint256 const& dirKey);
-
-    /** Drop the entry for `book` unconditionally.
-
-        Used as a safety hatch and by tests.
-    */
-    void
-    invalidate(Book const& book);
-
-    /** Drop every entry. */
-    void
-    clear();
-
-    [[nodiscard]] std::size_t
-    size() const;
-
-    [[nodiscard]] std::uint64_t
-    hits() const noexcept
-    {
-        return hits_.load(std::memory_order_relaxed);
-    }
-
-    [[nodiscard]] std::uint64_t
-    misses() const noexcept
-    {
-        return misses_.load(std::memory_order_relaxed);
-    }
-
-    [[nodiscard]] std::uint64_t
-    invalidations() const noexcept
-    {
-        return invalidations_.load(std::memory_order_relaxed);
-    }
-
-    /** Operator-facing kill switch.
-
-        When false, `BookTip` skips cache consults and writes entirely,
-        falling back to plain `succ()`. Default is true.
-    */
-    [[nodiscard]] static bool
-    enabled() noexcept;
-
-    static void
-    setEnabled(bool on) noexcept;
-
-private:
-    mutable std::mutex mutex_;
-    std::unordered_map<Book, TopOfBookEntry> map_;
-    mutable std::atomic<std::uint64_t> hits_{0};
-    mutable std::atomic<std::uint64_t> misses_{0};
-    std::atomic<std::uint64_t> invalidations_{0};
-};
-
-}  // namespace xrpl

include/xrpl/ledger/View.h

@@ -12,7 +12,6 @@
 #include <cstdint>
 #include <functional>
 #include <map>
-#include <memory>
 #include <optional>
 #include <set>
 #include <utility>
@@ -135,7 +134,7 @@ areCompatible(
 dirLink(
     ApplyView& view,
     AccountID const& owner,
-    std::shared_ptr<SLE>& object,
+    SLE::pointer& object,
     SF_UINT64 const& node = sfOwnerNode);
 
 /** Checks that can withdraw funds from an object to itself or a destination.
@@ -215,8 +214,8 @@ doWithdraw(
  * (if should not be skipped) and if the entry should be skipped. The status
  * is always tesSUCCESS if the entry should be skipped.
  */
-using EntryDeleter = std::function<
-    std::pair<TER, SkipEntry>(LedgerEntryType, uint256 const&, std::shared_ptr<SLE>&)>;
+using EntryDeleter =
+    std::function<std::pair<TER, SkipEntry>(LedgerEntryType, uint256 const&, SLE::pointer&)>;
 /** Cleanup owner directory entries on account delete.
  * Used for a regular and AMM accounts deletion. The caller
  * has to provide the deleter function, which handles details of

include/xrpl/ledger/detail/ApplyStateTable.h

@@ -8,8 +8,6 @@
 #include <xrpl/protocol/TxMeta.h>
 #include <xrpl/protocol/XRPAmount.h>
 
-#include <memory>
-
 namespace xrpl::detail {
 
 // Helper class that buffers modifications
@@ -26,7 +24,7 @@ private:
         Modify,
     };
 
-    using items_t = std::map<key_type, std::pair<Action, std::shared_ptr<SLE>>>;
+    using items_t = std::map<key_type, std::pair<Action, SLE::pointer>>;
 
     items_t items_;
     XRPAmount dropsDestroyed_{0};
@@ -60,10 +58,10 @@ public:
     [[nodiscard]] std::optional<key_type>
     succ(ReadView const& base, key_type const& key, std::optional<key_type> const& last) const;
 
-    [[nodiscard]] std::shared_ptr<SLE const>
+    [[nodiscard]] SLE::const_pointer
     read(ReadView const& base, Keylet const& k) const;
 
-    std::shared_ptr<SLE>
+    SLE::pointer
     peek(ReadView const& base, Keylet const& k);
 
     [[nodiscard]] std::size_t
@@ -75,23 +73,23 @@ public:
         std::function<void(
             uint256 const& key,
             bool isDelete,
-            std::shared_ptr<SLE const> const& before,
-            std::shared_ptr<SLE const> const& after)> const& func) const;
+            SLE::const_ref before,
+            SLE::const_ref after)> const& func) const;
 
     void
-    erase(ReadView const& base, std::shared_ptr<SLE> const& sle);
+    erase(ReadView const& base, SLE::ref sle);
 
     void
-    rawErase(ReadView const& base, std::shared_ptr<SLE> const& sle);
+    rawErase(ReadView const& base, SLE::ref sle);
 
     void
-    insert(ReadView const& base, std::shared_ptr<SLE> const& sle);
+    insert(ReadView const& base, SLE::ref sle);
 
     void
-    update(ReadView const& base, std::shared_ptr<SLE> const& sle);
+    update(ReadView const& base, SLE::ref sle);
 
     void
-    replace(ReadView const& base, std::shared_ptr<SLE> const& sle);
+    replace(ReadView const& base, SLE::ref sle);
 
     void
     destroyXRP(XRPAmount const& fee);
@@ -104,12 +102,12 @@ public:
     }
 
 private:
-    using Mods = hash_map<key_type, std::shared_ptr<SLE>>;
+    using Mods = hash_map<key_type, SLE::pointer>;
 
     static void
-    threadItem(TxMeta& meta, std::shared_ptr<SLE> const& to);
+    threadItem(TxMeta& meta, SLE::ref to);
 
-    std::shared_ptr<SLE>
+    SLE::pointer
     getForMod(ReadView const& base, key_type const& key, Mods& mods, beast::Journal j);
 
     void
@@ -119,7 +117,7 @@ private:
     threadOwners(
         ReadView const& base,
         TxMeta& meta,
-        std::shared_ptr<SLE const> const& sle,
+        SLE::const_ref sle,
         Mods& mods,
         beast::Journal j);
 };

include/xrpl/ledger/detail/ApplyViewBase.h

@@ -3,13 +3,8 @@
 #include <xrpl/ledger/ApplyView.h>
 #include <xrpl/ledger/ReadView.h>
 #include <xrpl/ledger/detail/ApplyStateTable.h>
-#include <xrpl/protocol/Book.h>
 #include <xrpl/protocol/XRPAmount.h>
 
-#include <unordered_set>
-#include <utility>
-#include <vector>
-
 namespace xrpl::detail {
 
 class ApplyViewBase : public ApplyView, public RawView
@@ -45,29 +40,9 @@ public:
     [[nodiscard]] std::optional<key_type>
     succ(key_type const& key, std::optional<key_type> const& last = std::nullopt) const override;
 
-    [[nodiscard]] std::shared_ptr<SLE const>
+    [[nodiscard]] SLE::const_pointer
     read(Keylet const& k) const override;
 
-    // Top-of-book cache hooks — delegated to the wrapped base view so
-    // sandboxed views share the underlying open-ledger cache.
-
-    [[nodiscard]] std::optional<uint256>
-    topOfBookFirstPage(Book const& book) const override;
-
-    void
-    recordTopOfBook(Book const& book, uint256 const& firstPageKey) const override;
-
-    void
-    notifyOfferInserted(Book const& book, uint256 const& dirKey, uint256 const& offerKey)
-        const override;
-
-    void
-    notifyOfferDeleted(Book const& book, uint256 const& dirKey, uint256 const& offerKey)
-        const override;
-
-    [[nodiscard]] std::optional<std::vector<uint256>>
-    orderedBook(Book const& book) const override;
-
     [[nodiscard]] std::unique_ptr<SlesType::iter_base>
     slesBegin() const override;
 
@@ -94,71 +69,36 @@ public:
     [[nodiscard]] ApplyFlags
     flags() const override;
 
-    std::shared_ptr<SLE>
+    SLE::pointer
     peek(Keylet const& k) override;
 
     void
-    erase(std::shared_ptr<SLE> const& sle) override;
+    erase(SLE::ref sle) override;
 
     void
-    insert(std::shared_ptr<SLE> const& sle) override;
+    insert(SLE::ref sle) override;
 
     void
-    update(std::shared_ptr<SLE> const& sle) override;
+    update(SLE::ref sle) override;
 
     // RawView
 
     void
-    rawErase(std::shared_ptr<SLE> const& sle) override;
+    rawErase(SLE::ref sle) override;
 
     void
-    rawInsert(std::shared_ptr<SLE> const& sle) override;
+    rawInsert(SLE::ref sle) override;
 
     void
-    rawReplace(std::shared_ptr<SLE> const& sle) override;
+    rawReplace(SLE::ref sle) override;
 
     void
     rawDestroyXRP(XRPAmount const& feeDrops) override;
 
-    /** Flush buffered top-of-book notifications to the wrapped base view.
-
-        Called by `Sandbox::apply` (and similar commit points) after the
-        state table itself has been applied. Notifications buffered during
-        the sandbox's lifetime are replayed against `base_` in insertion
-        order so the parent cache only sees changes that actually commit.
-    */
-    void
-    flushTopOfBookNotifications() const;
-
-    /** Discard buffered notifications (e.g. when a sandbox is dropped
-        without applying). Safe to call multiple times.
-    */
-    void
-    discardTopOfBookNotifications() const noexcept;
-
 protected:
     ApplyFlags flags_;
     ReadView const* base_;
     detail::ApplyStateTable items_;
-
-    // Top-of-book cache notifications are buffered here for the lifetime
-    // of the sandbox and only flushed to `base_` on `apply()`. This keeps
-    // rolled-back transactions (e.g. FillOrKill via the sbCancel branch
-    // of OfferCreate) from polluting the parent's cache.
-    //
-    // `dirtyBooks_` records every book mutated by buffered notifications;
-    // reads against `topOfBookFirstPage` skip the cache for these books so
-    // we never observe our own un-committed state. Outside of the dirty
-    // set, the parent's cache is trusted as usual.
-    struct OfferNote
-    {
-        Book book;
-        uint256 dirKey;
-        uint256 offerKey;
-        bool isDelete;
-    };
-    mutable std::vector<OfferNote> pendingTopOfBookNotifications_;
-    mutable std::unordered_set<Book> dirtyBooks_;
 };
 
 }  // namespace xrpl::detail

include/xrpl/ledger/detail/PersistentOrderTree.h

@@ -1,257 +0,0 @@
-#pragma once
-
-#include <xrpl/basics/base_uint.h>
-
-#include <cstdint>
-#include <memory>
-#include <optional>
-#include <vector>
-
-namespace xrpl::detail {
-
-/** Persistent (immutable, structurally-shared) ordered tree for the order-book
-    index.
-
-    A weight-balanced BST (Adams BB[α], the family used by Haskell `Data.Map`
-    and std::map-replacement libraries) of immutable `shared_ptr<const Node>`.
-    Keyed by `(dirRoot, insertSeq)`:
-
-      - `dirRoot` ascending == best-quality-first (book directory pages share a
-        prefix, quality is in the low bytes — lower key = better quality).
-      - `insertSeq` ascending within a `dirRoot` == directory append order
-        (the per-book monotonic counter mirrors `dirAppend`; `dirRemove`
-        preserves relative order, so this reproduces the directory walk
-        byte-for-byte).
-
-    Operations are persistent via path-copying: insert/delete reallocate only
-    the O(log n) nodes on the root→leaf path and SHARE every untouched subtree.
-    A "copy" of a tree is just copying the root `shared_ptr` — O(1) — which is
-    what lets the order-book index survive the open-ledger copy-on-write cheaply
-    and stay warm across transactions.
-
-    Immutable nodes are safe to share across threads/snapshots without locking.
-*/
-struct OrderTreeNode
-{
-    uint256 dirRoot;
-    std::uint64_t insertSeq;
-    uint256 offerKey;
-    std::uint32_t size;  // subtree node count (balance + rank)
-    std::shared_ptr<OrderTreeNode const> left;
-    std::shared_ptr<OrderTreeNode const> right;
-};
-
-using OrderTreePtr = std::shared_ptr<OrderTreeNode const>;
-
-// Weight-balance parameters (Adams). delta bounds the size ratio between
-// siblings; gamma chooses single vs double rotation.
-inline constexpr std::uint32_t kOtDelta = 3;
-inline constexpr std::uint32_t kOtGamma = 2;
-
-[[nodiscard]] inline std::uint32_t
-otSize(OrderTreePtr const& t) noexcept
-{
-    return t ? t->size : 0;
-}
-
-// -1 / 0 / +1 ordering on (dirRoot, insertSeq).
-[[nodiscard]] inline int
-otCmp(
-    uint256 const& aDir,
-    std::uint64_t aSeq,
-    uint256 const& bDir,
-    std::uint64_t bSeq) noexcept
-{
-    if (aDir < bDir)
-        return -1;
-    if (bDir < aDir)
-        return 1;
-    if (aSeq < bSeq)
-        return -1;
-    if (bSeq < aSeq)
-        return 1;
-    return 0;
-}
-
-[[nodiscard]] inline OrderTreePtr
-otNode(
-    uint256 const& dir,
-    std::uint64_t seq,
-    uint256 const& off,
-    OrderTreePtr l,
-    OrderTreePtr r)
-{
-    auto n = std::make_shared<OrderTreeNode>();
-    n->dirRoot = dir;
-    n->insertSeq = seq;
-    n->offerKey = off;
-    n->left = std::move(l);
-    n->right = std::move(r);
-    n->size = otSize(n->left) + otSize(n->right) + 1;
-    return n;
-}
-
-// Rebalance a node whose subtrees may violate the weight balance by one step.
-[[nodiscard]] inline OrderTreePtr
-otBalance(
-    uint256 const& dir,
-    std::uint64_t seq,
-    uint256 const& off,
-    OrderTreePtr const& l,
-    OrderTreePtr const& r)
-{
-    auto const ln = otSize(l);
-    auto const rn = otSize(r);
-
-    if (ln + rn <= 1)
-        return otNode(dir, seq, off, l, r);
-
-    if (rn > kOtDelta * ln)
-    {
-        // Right-heavy.
-        auto const& rl = r->left;
-        auto const& rr = r->right;
-        if (otSize(rl) < kOtGamma * otSize(rr))
-            // single left rotation
-            return otNode(
-                r->dirRoot,
-                r->insertSeq,
-                r->offerKey,
-                otNode(dir, seq, off, l, rl),
-                rr);
-        // double left rotation
-        return otNode(
-            rl->dirRoot,
-            rl->insertSeq,
-            rl->offerKey,
-            otNode(dir, seq, off, l, rl->left),
-            otNode(r->dirRoot, r->insertSeq, r->offerKey, rl->right, rr));
-    }
-
-    if (ln > kOtDelta * rn)
-    {
-        // Left-heavy.
-        auto const& ll = l->left;
-        auto const& lr = l->right;
-        if (otSize(lr) < kOtGamma * otSize(ll))
-            // single right rotation
-            return otNode(
-                l->dirRoot,
-                l->insertSeq,
-                l->offerKey,
-                ll,
-                otNode(dir, seq, off, lr, r));
-        // double right rotation
-        return otNode(
-            lr->dirRoot,
-            lr->insertSeq,
-            lr->offerKey,
-            otNode(l->dirRoot, l->insertSeq, l->offerKey, ll, lr->left),
-            otNode(dir, seq, off, lr->right, r));
-    }
-
-    return otNode(dir, seq, off, l, r);
-}
-
-[[nodiscard]] inline OrderTreePtr
-otInsert(OrderTreePtr const& t, uint256 const& dir, std::uint64_t seq, uint256 const& off)
-{
-    if (!t)
-        return otNode(dir, seq, off, nullptr, nullptr);
-    int const c = otCmp(dir, seq, t->dirRoot, t->insertSeq);
-    if (c < 0)
-        return otBalance(
-            t->dirRoot, t->insertSeq, t->offerKey, otInsert(t->left, dir, seq, off), t->right);
-    if (c > 0)
-        return otBalance(
-            t->dirRoot, t->insertSeq, t->offerKey, t->left, otInsert(t->right, dir, seq, off));
-    // Equal key: replace payload (keys are unique in practice; never hit).
-    return otNode(t->dirRoot, t->insertSeq, off, t->left, t->right);
-}
-
-// Remove the minimum node of a non-null tree; write its fields into `outMin`.
-[[nodiscard]] inline OrderTreePtr
-otDeleteMin(OrderTreePtr const& t, OrderTreeNode& outMin)
-{
-    if (!t->left)
-    {
-        outMin = *t;
-        return t->right;
-    }
-    return otBalance(
-        t->dirRoot, t->insertSeq, t->offerKey, otDeleteMin(t->left, outMin), t->right);
-}
-
-// Join two subtrees (all keys in l < all keys in r) by promoting r's minimum.
-[[nodiscard]] inline OrderTreePtr
-otGlue(OrderTreePtr const& l, OrderTreePtr const& r)
-{
-    if (!l)
-        return r;
-    if (!r)
-        return l;
-    OrderTreeNode minN;
-    auto const r2 = otDeleteMin(r, minN);
-    return otBalance(minN.dirRoot, minN.insertSeq, minN.offerKey, l, r2);
-}
-
-[[nodiscard]] inline OrderTreePtr
-otDelete(OrderTreePtr const& t, uint256 const& dir, std::uint64_t seq)
-{
-    if (!t)
-        return nullptr;
-    int const c = otCmp(dir, seq, t->dirRoot, t->insertSeq);
-    if (c < 0)
-        return otBalance(
-            t->dirRoot, t->insertSeq, t->offerKey, otDelete(t->left, dir, seq), t->right);
-    if (c > 0)
-        return otBalance(
-            t->dirRoot, t->insertSeq, t->offerKey, t->left, otDelete(t->right, dir, seq));
-    return otGlue(t->left, t->right);
-}
-
-// In-order traversal: appends offer keys best-quality-first, append order
-// within a level.
-inline void
-otInorder(OrderTreePtr const& t, std::vector<uint256>& out)
-{
-    if (!t)
-        return;
-    otInorder(t->left, out);
-    out.push_back(t->offerKey);
-    otInorder(t->right, out);
-}
-
-// Leftmost (best) offer key.
-[[nodiscard]] inline std::optional<uint256>
-otFirst(OrderTreePtr t)
-{
-    if (!t)
-        return std::nullopt;
-    while (t->left)
-        t = t->left;
-    return t->offerKey;
-}
-
-// Find the insertSeq for (dirRoot, offerKey). All nodes sharing a dirRoot form
-// a contiguous in-order range that may straddle a node's two children, so when
-// dirRoot matches we must check the node and both subtrees. O(level-size) worst
-// case; effectively O(log n) for front deletions (crossing consumes front-first
-// and the target is then the level's leftmost remaining node).
-[[nodiscard]] inline std::optional<std::uint64_t>
-otFindSeq(OrderTreePtr const& t, uint256 const& dir, uint256 const& off)
-{
-    if (!t)
-        return std::nullopt;
-    if (dir < t->dirRoot)
-        return otFindSeq(t->left, dir, off);
-    if (t->dirRoot < dir)
-        return otFindSeq(t->right, dir, off);
-    if (t->offerKey == off)
-        return t->insertSeq;
-    if (auto const l = otFindSeq(t->left, dir, off))
-        return l;
-    return otFindSeq(t->right, dir, off);
-}
-
-}  // namespace xrpl::detail

include/xrpl/ledger/detail/RawStateTable.h

@@ -49,15 +49,15 @@ public:
     succ(ReadView const& base, key_type const& key, std::optional<key_type> const& last) const;
 
     void
-    erase(std::shared_ptr<SLE> const& sle);
+    erase(SLE::ref sle);
 
     void
-    insert(std::shared_ptr<SLE> const& sle);
+    insert(SLE::ref sle);
 
     void
-    replace(std::shared_ptr<SLE> const& sle);
+    replace(SLE::ref sle);
 
-    [[nodiscard]] std::shared_ptr<SLE const>
+    [[nodiscard]] SLE::const_pointer
     read(ReadView const& base, Keylet const& k) const;
 
     void
@@ -84,10 +84,10 @@ private:
     struct SleAction
     {
         Action action;
-        std::shared_ptr<SLE> sle;
+        SLE::pointer sle;
 
         // Constructor needed for emplacement in std::map
-        SleAction(Action action, std::shared_ptr<SLE> const& sle) : action(action), sle(sle)
+        SleAction(Action action, SLE::pointer sle) : action(action), sle(std::move(sle))
         {
         }
     };

include/xrpl/ledger/helpers/AMMHelpers.h

@@ -792,7 +792,7 @@ deleteAMMAccount(Sandbox& view, Asset const& asset, Asset const& asset2, beast::
 void
 initializeFeeAuctionVote(
     ApplyView& view,
-    std::shared_ptr<SLE>& ammSle,
+    SLE::pointer& ammSle,
     AccountID const& account,
     Asset const& lptAsset,
     std::uint16_t tfee);
@@ -812,7 +812,7 @@ Expected<bool, TER>
 verifyAndAdjustLPTokenBalance(
     Sandbox& sb,
     STAmount const& lpTokens,
-    std::shared_ptr<SLE>& ammSle,
+    SLE::pointer& ammSle,
     AccountID const& account);
 
 }  // namespace xrpl

include/xrpl/ledger/helpers/AccountRootHelpers.h

@@ -9,7 +9,6 @@
 #include <xrpl/protocol/STLedgerEntry.h>
 #include <xrpl/protocol/TER.h>
 
-#include <memory>
 #include <set>
 #include <vector>
 
@@ -36,11 +35,7 @@ xrpLiquid(ReadView const& view, AccountID const& id, std::int32_t ownerCountAdj,
 
 /** Adjust the owner count up or down. */
 void
-adjustOwnerCount(
-    ApplyView& view,
-    std::shared_ptr<SLE> const& sle,
-    std::int32_t amount,
-    beast::Journal j);
+adjustOwnerCount(ApplyView& view, SLE::ref sle, std::int32_t amount, beast::Journal j);
 
 /** Returns IOU issuer transfer fee as Rate. Rate specifies
  * the fee as fractions of 1 billion. For example, 1% transfer rate
@@ -76,9 +71,7 @@ getPseudoAccountFields();
     - null pointer
 */
 [[nodiscard]] bool
-isPseudoAccount(
-    std::shared_ptr<SLE const> sleAcct,
-    std::set<SField const*> const& pseudoFieldFilter = {});
+isPseudoAccount(SLE::const_pointer sleAcct, std::set<SField const*> const& pseudoFieldFilter = {});
 
 /** Convenience overload that reads the account from the view. */
 [[nodiscard]] inline bool
@@ -98,7 +91,7 @@ isPseudoAccount(
  * before using a field. The amendment check is **not** performed in
  * createPseudoAccount.
  */
-[[nodiscard]] Expected<std::shared_ptr<SLE>, TER>
+[[nodiscard]] Expected<SLE::pointer, TER>
 createPseudoAccount(ApplyView& view, uint256 const& pseudoOwnerKey, SField const& ownerField);
 
 /** Checks the destination and tag.

include/xrpl/ledger/helpers/CredentialHelpers.h

@@ -23,7 +23,7 @@ checkExpired(SLE const& sleCredential, NetClock::time_point const& closed);
 
 // Actually remove a credentials object from the ledger
 [[nodiscard]] TER
-deleteSLE(ApplyView& view, std::shared_ptr<SLE> const& sleCredential, beast::Journal j);
+deleteSLE(ApplyView& view, SLE::ref sleCredential, beast::Journal j);
 
 // Amendment and parameters checks for sfCredentialIDs field
 NotTEC
@@ -70,7 +70,7 @@ verifyDepositPreauth(
     ApplyView& view,
     AccountID const& src,
     AccountID const& dst,
-    std::shared_ptr<SLE const> const& sleDst,
+    SLE::const_ref sleDst,
     beast::Journal j);
 
 }  // namespace xrpl

include/xrpl/ledger/helpers/DelegateHelpers.h

@@ -15,7 +15,7 @@ namespace xrpl {
  * if not.
  */
 NotTEC
-checkTxPermission(std::shared_ptr<SLE const> const& delegate, STTx const& tx);
+checkTxPermission(SLE::const_ref delegate, STTx const& tx);
 
 /**
  * Load the granular permissions granted to the delegate account for the
@@ -28,7 +28,7 @@ checkTxPermission(std::shared_ptr<SLE const> const& delegate, STTx const& tx);
  */
 void
 loadGranularPermission(
-    std::shared_ptr<SLE const> const& delegate,
+    SLE::const_ref delegate,
     TxType const& type,
     std::unordered_set<GranularPermissionType>& granularPermissions);
 

include/xrpl/ledger/helpers/DirectoryHelpers.h

@@ -115,7 +115,7 @@ bool
 cdirFirst(
     ReadView const& view,
     uint256 const& root,
-    std::shared_ptr<SLE const>& page,
+    SLE::const_pointer& page,
     unsigned int& index,
     uint256& entry);
 
@@ -123,7 +123,7 @@ bool
 dirFirst(
     ApplyView& view,
     uint256 const& root,
-    std::shared_ptr<SLE>& page,
+    SLE::pointer& page,
     unsigned int& index,
     uint256& entry);
 /** @} */
@@ -147,7 +147,7 @@ bool
 cdirNext(
     ReadView const& view,
     uint256 const& root,
-    std::shared_ptr<SLE const>& page,
+    SLE::const_pointer& page,
     unsigned int& index,
     uint256& entry);
 
@@ -155,17 +155,14 @@ bool
 dirNext(
     ApplyView& view,
     uint256 const& root,
-    std::shared_ptr<SLE>& page,
+    SLE::pointer& page,
     unsigned int& index,
     uint256& entry);
 /** @} */
 
 /** Iterate all items in the given directory. */
 void
-forEachItem(
-    ReadView const& view,
-    Keylet const& root,
-    std::function<void(std::shared_ptr<SLE const> const&)> const& f);
+forEachItem(ReadView const& view, Keylet const& root, std::function<void(SLE::const_ref)> const& f);
 
 /** Iterate all items after an item in the given directory.
     @param after The key of the item to start after
@@ -180,14 +177,11 @@ forEachItemAfter(
     uint256 const& after,
     std::uint64_t const hint,
     unsigned int limit,
-    std::function<bool(std::shared_ptr<SLE const> const&)> const& f);
+    std::function<bool(SLE::const_ref)> const& f);
 
 /** Iterate all items in an account's owner directory. */
 inline void
-forEachItem(
-    ReadView const& view,
-    AccountID const& id,
-    std::function<void(std::shared_ptr<SLE const> const&)> const& f)
+forEachItem(ReadView const& view, AccountID const& id, std::function<void(SLE::const_ref)> const& f)
 {
     forEachItem(view, keylet::ownerDir(id), f);
 }
@@ -205,7 +199,7 @@ forEachItemAfter(
     uint256 const& after,
     std::uint64_t const hint,
     unsigned int limit,
-    std::function<bool(std::shared_ptr<SLE const> const&)> const& f)
+    std::function<bool(SLE::const_ref)> const& f)
 {
     return forEachItemAfter(view, keylet::ownerDir(id), after, hint, limit, f);
 }

include/xrpl/ledger/helpers/EscrowHelpers.h

@@ -18,7 +18,7 @@ TER
 escrowUnlockApplyHelper(
     ApplyView& view,
     Rate lockedRate,
-    std::shared_ptr<SLE> const& sleDest,
+    SLE::ref sleDest,
     STAmount const& xrpBalance,
     STAmount const& amount,
     AccountID const& issuer,
@@ -32,7 +32,7 @@ inline TER
 escrowUnlockApplyHelper<Issue>(
     ApplyView& view,
     Rate lockedRate,
-    std::shared_ptr<SLE> const& sleDest,
+    SLE::ref sleDest,
     STAmount const& xrpBalance,
     STAmount const& amount,
     AccountID const& issuer,
@@ -162,7 +162,7 @@ inline TER
 escrowUnlockApplyHelper<MPTIssue>(
     ApplyView& view,
     Rate lockedRate,
-    std::shared_ptr<SLE> const& sleDest,
+    SLE::ref sleDest,
     STAmount const& xrpBalance,
     STAmount const& amount,
     AccountID const& issuer,

include/xrpl/ledger/helpers/LendingHelpers.h

@@ -461,6 +461,7 @@ loanAccruedInterest(
 
 ExtendedPaymentComponents
 computeOverpaymentComponents(
+    Rules const& rules,
     Asset const& asset,
     int32_t const loanScale,
     Number const& overpayment,

include/xrpl/ledger/helpers/NFTokenHelpers.h

@@ -28,10 +28,9 @@ findToken(ReadView const& view, AccountID const& owner, uint256 const& nftokenID
 struct TokenAndPage
 {
     STObject token;
-    std::shared_ptr<SLE> page;
+    SLE::pointer page;
 
-    TokenAndPage(STObject token, std::shared_ptr<SLE> page)
-        : token(std::move(token)), page(std::move(page))
+    TokenAndPage(STObject token, SLE::pointer page) : token(std::move(token)), page(std::move(page))
     {
     }
 };
@@ -47,11 +46,7 @@ TER
 removeToken(ApplyView& view, AccountID const& owner, uint256 const& nftokenID);
 
 TER
-removeToken(
-    ApplyView& view,
-    AccountID const& owner,
-    uint256 const& nftokenID,
-    std::shared_ptr<SLE> const& page);
+removeToken(ApplyView& view, AccountID const& owner, uint256 const& nftokenID, SLE::ref page);
 
 /** Deletes the given token offer.
 
@@ -63,7 +58,7 @@ removeToken(
     The offer also consumes one incremental reserve.
  */
 bool
-deleteTokenOffer(ApplyView& view, std::shared_ptr<SLE> const& offer);
+deleteTokenOffer(ApplyView& view, SLE::ref offer);
 
 /** Repairs the links in an NFTokenPage directory.
 

include/xrpl/ledger/helpers/OfferHelpers.h

@@ -5,8 +5,6 @@
 #include <xrpl/protocol/STLedgerEntry.h>
 #include <xrpl/protocol/TER.h>
 
-#include <memory>
-
 namespace xrpl {
 
 /** Delete an offer.
@@ -23,6 +21,6 @@ namespace xrpl {
 */
 // [[nodiscard]] // nodiscard commented out so Flow, BookTip and others compile.
 TER
-offerDelete(ApplyView& view, std::shared_ptr<SLE> const& sle, beast::Journal j);
+offerDelete(ApplyView& view, SLE::ref sle, beast::Journal j);
 
 }  // namespace xrpl

include/xrpl/ledger/helpers/PaymentChannelHelpers.h

@@ -8,10 +8,6 @@
 namespace xrpl {
 
 TER
-closeChannel(
-    std::shared_ptr<SLE> const& slep,
-    ApplyView& view,
-    uint256 const& key,
-    beast::Journal j);
+closeChannel(SLE::ref slep, ApplyView& view, uint256 const& key, beast::Journal j);
 
 }  // namespace xrpl

include/xrpl/ledger/helpers/RippleStateHelpers.h

@@ -154,7 +154,7 @@ trustCreate(
 [[nodiscard]] TER
 trustDelete(
     ApplyView& view,
-    std::shared_ptr<SLE> const& sleRippleState,
+    SLE::ref sleRippleState,
     AccountID const& uLowAccountID,
     AccountID const& uHighAccountID,
     beast::Journal j);
@@ -248,7 +248,7 @@ removeEmptyHolding(
 [[nodiscard]] TER
 deleteAMMTrustLine(
     ApplyView& view,
-    std::shared_ptr<SLE> sleState,
+    SLE::pointer sleState,
     std::optional<AccountID> const& ammAccountID,
     beast::Journal j);
 
@@ -258,7 +258,7 @@ deleteAMMTrustLine(
 [[nodiscard]] TER
 deleteAMMMPToken(
     ApplyView& view,
-    std::shared_ptr<SLE> sleMPT,
+    SLE::pointer sleMPT,
     AccountID const& ammAccountID,
     beast::Journal j);
 

include/xrpl/ledger/helpers/VaultHelpers.h

@@ -5,7 +5,6 @@
 #include <xrpl/protocol/STAmount.h>
 #include <xrpl/protocol/STLedgerEntry.h>
 
-#include <memory>
 #include <optional>
 
 namespace xrpl {
@@ -21,10 +20,7 @@ namespace xrpl {
     @return The number of shares, or nullopt on error.
 */
 [[nodiscard]] std::optional<STAmount>
-assetsToSharesDeposit(
-    std::shared_ptr<SLE const> const& vault,
-    std::shared_ptr<SLE const> const& issuance,
-    STAmount const& assets);
+assetsToSharesDeposit(SLE::const_ref vault, SLE::const_ref issuance, STAmount const& assets);
 
 /** From the perspective of a vault, return the number of assets to take from
     depositor when they receive a fixed amount of shares. Note, since shares are
@@ -37,10 +33,7 @@ assetsToSharesDeposit(
     @return The number of assets, or nullopt on error.
 */
 [[nodiscard]] std::optional<STAmount>
-sharesToAssetsDeposit(
-    std::shared_ptr<SLE const> const& vault,
-    std::shared_ptr<SLE const> const& issuance,
-    STAmount const& shares);
+sharesToAssetsDeposit(SLE::const_ref vault, SLE::const_ref issuance, STAmount const& shares);
 
 /** Controls whether to truncate shares instead of rounding. */
 enum class TruncateShares : bool { No = false, Yes = true };
@@ -69,8 +62,8 @@ enum class WaiveUnrealizedLoss : bool { No = false, Yes = true };
 */
 [[nodiscard]] std::optional<STAmount>
 assetsToSharesWithdraw(
-    std::shared_ptr<SLE const> const& vault,
-    std::shared_ptr<SLE const> const& issuance,
+    SLE::const_ref vault,
+    SLE::const_ref issuance,
     STAmount const& assets,
     TruncateShares truncate = TruncateShares::No,
     WaiveUnrealizedLoss waive = WaiveUnrealizedLoss::No);
@@ -89,8 +82,8 @@ assetsToSharesWithdraw(
 */
 [[nodiscard]] std::optional<STAmount>
 sharesToAssetsWithdraw(
-    std::shared_ptr<SLE const> const& vault,
-    std::shared_ptr<SLE const> const& issuance,
+    SLE::const_ref vault,
+    SLE::const_ref issuance,
     STAmount const& shares,
     WaiveUnrealizedLoss waive = WaiveUnrealizedLoss::No);
 
@@ -104,9 +97,6 @@ sharesToAssetsWithdraw(
                     both the share MPTID and the outstanding-amount total.
 */
 [[nodiscard]] bool
-isSoleShareholder(
-    ReadView const& view,
-    AccountID const& account,
-    std::shared_ptr<SLE const> const& issuance);
+isSoleShareholder(ReadView const& view, AccountID const& account, SLE::const_ref issuance);
 
 }  // namespace xrpl

include/xrpl/nodestore/Database.h

@@ -131,6 +131,10 @@ public:
         std::uint32_t ledgerSeq,
         std::function<void(std::shared_ptr<NodeObject> const&)>&& callback);
 
+    /** Remove expired entries from the positive and negative caches. */
+    virtual void
+    sweep() = 0;
+
     /** Gather statistics pertaining to read and write activities.
      *
      * @param obj Json object reference into which to place counters.

include/xrpl/nodestore/detail/DatabaseNodeImp.h

@@ -22,6 +22,32 @@ public:
         beast::Journal j)
         : Database(scheduler, readThreads, config, j), backend_(std::move(backend))
     {
+        std::optional<int> cacheSize, cacheAge;
+
+        if (config.exists("cache_size"))
+        {
+            cacheSize = get<int>(config, "cache_size");
+            if (cacheSize.value() < 0)
+                Throw<std::runtime_error>("Specified negative value for cache_size");
+        }
+
+        if (config.exists("cache_age"))
+        {
+            cacheAge = get<int>(config, "cache_age");
+            if (cacheAge.value() < 0)
+                Throw<std::runtime_error>("Specified negative value for cache_age");
+        }
+
+        if (cacheSize.has_value() || cacheAge.has_value())
+        {
+            cache_ = std::make_shared<TaggedCache<uint256, NodeObject>>(
+                "DatabaseNodeImp",
+                cacheSize.value_or(0),
+                std::chrono::minutes(cacheAge.value_or(0)),
+                stopwatch(),
+                j);
+        }
+
         XRPL_ASSERT(
             backend_,
             "xrpl::NodeStore::DatabaseNodeImp::DatabaseNodeImp : non-null "
@@ -73,7 +99,13 @@ public:
         std::uint32_t ledgerSeq,
         std::function<void(std::shared_ptr<NodeObject> const&)>&& callback) override;
 
+    void
+    sweep() override;
+
 private:
+    // Cache for database objects. This cache is not always initialized. Check
+    // for null before using.
+    std::shared_ptr<TaggedCache<uint256, NodeObject>> cache_;
     // Persistent key/value storage
     std::shared_ptr<Backend> backend_;
 

include/xrpl/nodestore/detail/DatabaseRotatingImp.h

@@ -55,6 +55,9 @@ public:
     void
     sync() override;
 
+    void
+    sweep() override;
+
 private:
     std::shared_ptr<Backend> writableBackend_;
     std::shared_ptr<Backend> archiveBackend_;

include/xrpl/protocol_autogen/LedgerEntryBase.h

@@ -27,7 +27,7 @@ public:
      * @brief Construct a ledger entry wrapper from an existing SLE object.
      * @param sle The underlying serialized ledger entry to wrap
      */
-    explicit LedgerEntryBase(std::shared_ptr<SLE const> sle) : sle_(std::move(sle))
+    explicit LedgerEntryBase(SLE::const_pointer sle) : sle_(std::move(sle))
     {
     }
 
@@ -151,7 +151,7 @@ public:
      * @return A constant reference to the underlying SLE object
      */
     [[nodiscard]]
-    std::shared_ptr<SLE const>
+    SLE::const_pointer
     getSle() const
     {
         return sle_;
@@ -159,7 +159,7 @@ public:
 
 protected:
     /** @brief The underlying serialized ledger entry being wrapped. */
-    std::shared_ptr<SLE const> sle_;
+    SLE::const_pointer sle_;
 };
 
 }  // namespace xrpl::ledger_entries

include/xrpl/protocol_autogen/ledger_entries/AMM.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a AMM ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit AMM(std::shared_ptr<SLE const> sle)
+    explicit AMM(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -256,7 +256,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    AMMBuilder(std::shared_ptr<SLE const> sle)
+    AMMBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltAMM)
         {

include/xrpl/protocol_autogen/ledger_entries/AccountRoot.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a AccountRoot ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit AccountRoot(std::shared_ptr<SLE const> sle)
+    explicit AccountRoot(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -555,7 +555,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    AccountRootBuilder(std::shared_ptr<SLE const> sle)
+    AccountRootBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltACCOUNT_ROOT)
         {

include/xrpl/protocol_autogen/ledger_entries/Amendments.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Amendments ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Amendments(std::shared_ptr<SLE const> sle)
+    explicit Amendments(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -166,7 +166,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    AmendmentsBuilder(std::shared_ptr<SLE const> sle)
+    AmendmentsBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltAMENDMENTS)
         {

include/xrpl/protocol_autogen/ledger_entries/Bridge.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Bridge ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Bridge(std::shared_ptr<SLE const> sle)
+    explicit Bridge(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -210,7 +210,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    BridgeBuilder(std::shared_ptr<SLE const> sle)
+    BridgeBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltBRIDGE)
         {

include/xrpl/protocol_autogen/ledger_entries/Check.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Check ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Check(std::shared_ptr<SLE const> sle)
+    explicit Check(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -269,7 +269,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    CheckBuilder(std::shared_ptr<SLE const> sle)
+    CheckBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltCHECK)
         {

include/xrpl/protocol_autogen/ledger_entries/Credential.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Credential ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Credential(std::shared_ptr<SLE const> sle)
+    explicit Credential(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -219,7 +219,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    CredentialBuilder(std::shared_ptr<SLE const> sle)
+    CredentialBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltCREDENTIAL)
         {

include/xrpl/protocol_autogen/ledger_entries/DID.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a DID ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit DID(std::shared_ptr<SLE const> sle)
+    explicit DID(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -193,7 +193,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    DIDBuilder(std::shared_ptr<SLE const> sle)
+    DIDBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltDID)
         {

include/xrpl/protocol_autogen/ledger_entries/Delegate.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Delegate ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Delegate(std::shared_ptr<SLE const> sle)
+    explicit Delegate(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -172,7 +172,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    DelegateBuilder(std::shared_ptr<SLE const> sle)
+    DelegateBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltDELEGATE)
         {

include/xrpl/protocol_autogen/ledger_entries/DepositPreauth.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a DepositPreauth ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit DepositPreauth(std::shared_ptr<SLE const> sle)
+    explicit DepositPreauth(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -170,7 +170,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    DepositPreauthBuilder(std::shared_ptr<SLE const> sle)
+    DepositPreauthBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltDEPOSIT_PREAUTH)
         {

include/xrpl/protocol_autogen/ledger_entries/DirectoryNode.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a DirectoryNode ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit DirectoryNode(std::shared_ptr<SLE const> sle)
+    explicit DirectoryNode(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -431,7 +431,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    DirectoryNodeBuilder(std::shared_ptr<SLE const> sle)
+    DirectoryNodeBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltDIR_NODE)
         {

include/xrpl/protocol_autogen/ledger_entries/Escrow.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Escrow ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Escrow(std::shared_ptr<SLE const> sle)
+    explicit Escrow(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -363,7 +363,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    EscrowBuilder(std::shared_ptr<SLE const> sle)
+    EscrowBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltESCROW)
         {

include/xrpl/protocol_autogen/ledger_entries/FeeSettings.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a FeeSettings ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit FeeSettings(std::shared_ptr<SLE const> sle)
+    explicit FeeSettings(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -285,7 +285,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    FeeSettingsBuilder(std::shared_ptr<SLE const> sle)
+    FeeSettingsBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltFEE_SETTINGS)
         {

include/xrpl/protocol_autogen/ledger_entries/LedgerHashes.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a LedgerHashes ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit LedgerHashes(std::shared_ptr<SLE const> sle)
+    explicit LedgerHashes(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -130,7 +130,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    LedgerHashesBuilder(std::shared_ptr<SLE const> sle)
+    LedgerHashesBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltLEDGER_HASHES)
         {

include/xrpl/protocol_autogen/ledger_entries/Loan.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Loan ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Loan(std::shared_ptr<SLE const> sle)
+    explicit Loan(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -607,7 +607,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    LoanBuilder(std::shared_ptr<SLE const> sle)
+    LoanBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltLOAN)
         {

include/xrpl/protocol_autogen/ledger_entries/LoanBroker.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a LoanBroker ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit LoanBroker(std::shared_ptr<SLE const> sle)
+    explicit LoanBroker(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -378,7 +378,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    LoanBrokerBuilder(std::shared_ptr<SLE const> sle)
+    LoanBrokerBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltLOAN_BROKER)
         {

include/xrpl/protocol_autogen/ledger_entries/MPToken.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a MPToken ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit MPToken(std::shared_ptr<SLE const> sle)
+    explicit MPToken(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -182,7 +182,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    MPTokenBuilder(std::shared_ptr<SLE const> sle)
+    MPTokenBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltMPTOKEN)
         {

include/xrpl/protocol_autogen/ledger_entries/MPTokenIssuance.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a MPTokenIssuance ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit MPTokenIssuance(std::shared_ptr<SLE const> sle)
+    explicit MPTokenIssuance(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -339,7 +339,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    MPTokenIssuanceBuilder(std::shared_ptr<SLE const> sle)
+    MPTokenIssuanceBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltMPTOKEN_ISSUANCE)
         {

include/xrpl/protocol_autogen/ledger_entries/NFTokenOffer.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a NFTokenOffer ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit NFTokenOffer(std::shared_ptr<SLE const> sle)
+    explicit NFTokenOffer(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -208,7 +208,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    NFTokenOfferBuilder(std::shared_ptr<SLE const> sle)
+    NFTokenOfferBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltNFTOKEN_OFFER)
         {

include/xrpl/protocol_autogen/ledger_entries/NFTokenPage.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a NFTokenPage ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit NFTokenPage(std::shared_ptr<SLE const> sle)
+    explicit NFTokenPage(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -157,7 +157,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    NFTokenPageBuilder(std::shared_ptr<SLE const> sle)
+    NFTokenPageBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltNFTOKEN_PAGE)
         {

include/xrpl/protocol_autogen/ledger_entries/NegativeUNL.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a NegativeUNL ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit NegativeUNL(std::shared_ptr<SLE const> sle)
+    explicit NegativeUNL(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -190,7 +190,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    NegativeUNLBuilder(std::shared_ptr<SLE const> sle)
+    NegativeUNLBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltNEGATIVE_UNL)
         {

include/xrpl/protocol_autogen/ledger_entries/Offer.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Offer ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Offer(std::shared_ptr<SLE const> sle)
+    explicit Offer(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -259,7 +259,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    OfferBuilder(std::shared_ptr<SLE const> sle)
+    OfferBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltOFFER)
         {

include/xrpl/protocol_autogen/ledger_entries/Oracle.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Oracle ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Oracle(std::shared_ptr<SLE const> sle)
+    explicit Oracle(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -222,7 +222,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    OracleBuilder(std::shared_ptr<SLE const> sle)
+    OracleBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltORACLE)
         {

include/xrpl/protocol_autogen/ledger_entries/PayChannel.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a PayChannel ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit PayChannel(std::shared_ptr<SLE const> sle)
+    explicit PayChannel(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -330,7 +330,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    PayChannelBuilder(std::shared_ptr<SLE const> sle)
+    PayChannelBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltPAYCHAN)
         {

include/xrpl/protocol_autogen/ledger_entries/PermissionedDomain.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a PermissionedDomain ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit PermissionedDomain(std::shared_ptr<SLE const> sle)
+    explicit PermissionedDomain(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -148,7 +148,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    PermissionedDomainBuilder(std::shared_ptr<SLE const> sle)
+    PermissionedDomainBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltPERMISSIONED_DOMAIN)
         {

include/xrpl/protocol_autogen/ledger_entries/RippleState.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a RippleState ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit RippleState(std::shared_ptr<SLE const> sle)
+    explicit RippleState(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -278,7 +278,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    RippleStateBuilder(std::shared_ptr<SLE const> sle)
+    RippleStateBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltRIPPLE_STATE)
         {

include/xrpl/protocol_autogen/ledger_entries/SignerList.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a SignerList ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit SignerList(std::shared_ptr<SLE const> sle)
+    explicit SignerList(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -172,7 +172,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    SignerListBuilder(std::shared_ptr<SLE const> sle)
+    SignerListBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltSIGNER_LIST)
         {

include/xrpl/protocol_autogen/ledger_entries/Ticket.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Ticket ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Ticket(std::shared_ptr<SLE const> sle)
+    explicit Ticket(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -134,7 +134,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    TicketBuilder(std::shared_ptr<SLE const> sle)
+    TicketBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltTICKET)
         {

include/xrpl/protocol_autogen/ledger_entries/Vault.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a Vault ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit Vault(std::shared_ptr<SLE const> sle)
+    explicit Vault(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -330,7 +330,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    VaultBuilder(std::shared_ptr<SLE const> sle)
+    VaultBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltVAULT)
         {

include/xrpl/protocol_autogen/ledger_entries/XChainOwnedClaimID.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a XChainOwnedClaimID ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit XChainOwnedClaimID(std::shared_ptr<SLE const> sle)
+    explicit XChainOwnedClaimID(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -187,7 +187,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    XChainOwnedClaimIDBuilder(std::shared_ptr<SLE const> sle)
+    XChainOwnedClaimIDBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltXCHAIN_OWNED_CLAIM_ID)
         {

include/xrpl/protocol_autogen/ledger_entries/XChainOwnedCreateAccountClaimID.h

@@ -33,7 +33,7 @@ public:
      * @brief Construct a XChainOwnedCreateAccountClaimID ledger entry wrapper from an existing SLE object.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    explicit XChainOwnedCreateAccountClaimID(std::shared_ptr<SLE const> sle)
+    explicit XChainOwnedCreateAccountClaimID(SLE::const_pointer sle)
         : LedgerEntryBase(std::move(sle))
     {
         // Verify ledger entry type
@@ -161,7 +161,7 @@ public:
      * @param sle The existing ledger entry to copy from.
      * @throws std::runtime_error if the ledger entry type doesn't match.
      */
-    XChainOwnedCreateAccountClaimIDBuilder(std::shared_ptr<SLE const> sle)
+    XChainOwnedCreateAccountClaimIDBuilder(SLE::const_pointer sle)
     {
         if (sle->at(sfLedgerEntryType) != ltXCHAIN_OWNED_CREATE_ACCOUNT_CLAIM_ID)
         {

include/xrpl/shamap/SHAMap.h

@@ -85,7 +85,7 @@ private:
     /** The sequence of the ledger that this map references, if any. */
     std::uint32_t ledgerSeq_ = 0;
 
-    intr_ptr::SharedPtr<SHAMapTreeNode> root_;
+    SHAMapTreeNodePtr root_;
     mutable SHAMapState state_;
     SHAMapType const type_;
     bool backed_ = true;         // Map is backed by the database
@@ -326,36 +326,32 @@ public:
     invariants() const;
 
 private:
-    using SharedPtrNodeStack =
-        std::stack<std::pair<intr_ptr::SharedPtr<SHAMapTreeNode>, SHAMapNodeID>>;
+    using SharedPtrNodeStack = std::stack<std::pair<SHAMapTreeNodePtr, SHAMapNodeID>>;
     using DeltaRef =
         std::pair<boost::intrusive_ptr<SHAMapItem const>, boost::intrusive_ptr<SHAMapItem const>>;
 
     // tree node cache operations
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     cacheLookup(SHAMapHash const& hash) const;
 
     void
-    canonicalize(SHAMapHash const& hash, intr_ptr::SharedPtr<SHAMapTreeNode>&) const;
+    canonicalize(SHAMapHash const& hash, SHAMapTreeNodePtr&) const;
 
     // database operations
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     fetchNodeFromDB(SHAMapHash const& hash) const;
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     fetchNodeNT(SHAMapHash const& hash) const;
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     fetchNodeNT(SHAMapHash const& hash, SHAMapSyncFilter* filter) const;
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     fetchNode(SHAMapHash const& hash) const;
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     checkFilter(SHAMapHash const& hash, SHAMapSyncFilter* filter) const;
 
     /** Update hashes up to the root */
     void
-    dirtyUp(
-        SharedPtrNodeStack& stack,
-        uint256 const& target,
-        intr_ptr::SharedPtr<SHAMapTreeNode> terminal);
+    dirtyUp(SharedPtrNodeStack& stack, uint256 const& target, SHAMapTreeNodePtr terminal);
 
     /** Walk towards the specified id, returning the node.  Caller must check
         if the return is nullptr, and if not, if the node->peekItem()->key() ==
@@ -377,25 +373,21 @@ private:
     preFlushNode(intr_ptr::SharedPtr<Node> node) const;
 
     /** write and canonicalize modified node */
-    intr_ptr::SharedPtr<SHAMapTreeNode>
-    writeNode(NodeObjectType t, intr_ptr::SharedPtr<SHAMapTreeNode> node) const;
+    SHAMapTreeNodePtr
+    writeNode(NodeObjectType t, SHAMapTreeNodePtr node) const;
 
     // returns the first item at or below this node
     SHAMapLeafNode*
-    firstBelow(intr_ptr::SharedPtr<SHAMapTreeNode>, SharedPtrNodeStack& stack, int branch = 0)
-        const;
+    firstBelow(SHAMapTreeNodePtr node, SharedPtrNodeStack& stack, int branch = 0) const;
 
     // returns the last item at or below this node
     SHAMapLeafNode*
-    lastBelow(
-        intr_ptr::SharedPtr<SHAMapTreeNode> node,
-        SharedPtrNodeStack& stack,
-        int branch = kBranchFactor) const;
+    lastBelow(SHAMapTreeNodePtr node, SharedPtrNodeStack& stack, int branch = kBranchFactor) const;
 
     // helper function for firstBelow and lastBelow
     SHAMapLeafNode*
     belowHelper(
-        intr_ptr::SharedPtr<SHAMapTreeNode> node,
+        SHAMapTreeNodePtr node,
         SharedPtrNodeStack& stack,
         int branch,
         std::tuple<int, std::function<bool(int)>, std::function<void(int&)>> const& loopParams)
@@ -407,15 +399,14 @@ private:
     descend(SHAMapInnerNode*, int branch) const;
     SHAMapTreeNode*
     descendThrow(SHAMapInnerNode*, int branch) const;
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     descend(SHAMapInnerNode&, int branch) const;
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     descendThrow(SHAMapInnerNode&, int branch) const;
 
     // Descend with filter
     // If pending, callback is called as if it called fetchNodeNT
-    using descendCallback =
-        std::function<void(intr_ptr::SharedPtr<SHAMapTreeNode>, SHAMapHash const&)>;
+    using descendCallback = std::function<void(SHAMapTreeNodePtr, SHAMapHash const&)>;
     SHAMapTreeNode*
     descendAsync(
         SHAMapInnerNode* parent,
@@ -433,7 +424,7 @@ private:
 
     // Non-storing
     // Does not hook the returned node to its parent
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     descendNoStore(SHAMapInnerNode&, int branch) const;
 
     /** If there is only one leaf below this node, get its contents */
@@ -495,10 +486,10 @@ private:
 
         // nodes we may have acquired from deferred reads
         using DeferredNode = std::tuple<
-            SHAMapInnerNode*,                      // parent node
-            SHAMapNodeID,                          // parent node ID
-            int,                                   // branch
-            intr_ptr::SharedPtr<SHAMapTreeNode>>;  // node
+            SHAMapInnerNode*,    // parent node
+            SHAMapNodeID,        // parent node ID
+            int,                 // branch
+            SHAMapTreeNodePtr>;  // node
 
         int deferred;
         std::mutex deferLock;
@@ -524,7 +515,7 @@ private:
     gmnProcessDeferredReads(MissingNodes&);
 
     // fetch from DB helper function
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     finishFetch(SHAMapHash const& hash, std::shared_ptr<NodeObject> const& object) const;
 };
 

include/xrpl/shamap/SHAMapAccountStateLeafNode.h

@@ -27,7 +27,7 @@ public:
     {
     }
 
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     clone(std::uint32_t cowid) const final
     {
         return intr_ptr::makeShared<SHAMapAccountStateLeafNode>(item_, cowid, hash_);

include/xrpl/shamap/SHAMapInnerNode.h

@@ -87,7 +87,7 @@ public:
     void
     partialDestructor() override;
 
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     clone(std::uint32_t cowid) const override;
 
     SHAMapNodeType
@@ -121,19 +121,19 @@ public:
     getChildHash(int m) const;
 
     void
-    setChild(int m, intr_ptr::SharedPtr<SHAMapTreeNode> child);
+    setChild(int m, SHAMapTreeNodePtr child);
 
     void
-    shareChild(int m, intr_ptr::SharedPtr<SHAMapTreeNode> const& child);
+    shareChild(int m, SHAMapTreeNodePtr const& child);
 
     SHAMapTreeNode*
     getChildPointer(int branch);
 
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     getChild(int branch);
 
-    intr_ptr::SharedPtr<SHAMapTreeNode>
-    canonicalizeChild(int branch, intr_ptr::SharedPtr<SHAMapTreeNode> node);
+    SHAMapTreeNodePtr
+    canonicalizeChild(int branch, SHAMapTreeNodePtr node);
 
     // sync functions
     bool
@@ -161,10 +161,10 @@ public:
     void
     invariants(bool isRoot = false) const override;
 
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeFullInner(Slice data, SHAMapHash const& hash, bool hashValid);
 
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeCompressedInner(Slice data);
 };
 

include/xrpl/shamap/SHAMapTreeNode.h

@@ -13,6 +13,9 @@
 
 namespace xrpl {
 
+class SHAMapTreeNode;
+using SHAMapTreeNodePtr = intr_ptr::SharedPtr<SHAMapTreeNode>;
+
 // These are wire-protocol identifiers used during serialization to encode the
 // type of a node. They should not be arbitrarily be changed.
 static constexpr unsigned char const kWireTypeTransaction = 0;
@@ -112,7 +115,7 @@ public:
     }
 
     /** Make a copy of this node, setting the owner. */
-    virtual intr_ptr::SharedPtr<SHAMapTreeNode>
+    virtual SHAMapTreeNodePtr
     clone(std::uint32_t cowid) const = 0;
     /** @} */
 
@@ -153,20 +156,20 @@ public:
     virtual void
     invariants(bool isRoot = false) const = 0;
 
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeFromPrefix(Slice rawNode, SHAMapHash const& hash);
 
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeFromWire(Slice rawNode);
 
 private:
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeTransaction(Slice data, SHAMapHash const& hash, bool hashValid);
 
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeAccountState(Slice data, SHAMapHash const& hash, bool hashValid);
 
-    static intr_ptr::SharedPtr<SHAMapTreeNode>
+    static SHAMapTreeNodePtr
     makeTransactionWithMeta(Slice data, SHAMapHash const& hash, bool hashValid);
 };
 

include/xrpl/shamap/SHAMapTxLeafNode.h

@@ -26,7 +26,7 @@ public:
     {
     }
 
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     clone(std::uint32_t cowid) const final
     {
         return intr_ptr::makeShared<SHAMapTxLeafNode>(item_, cowid, hash_);

include/xrpl/shamap/SHAMapTxPlusMetaLeafNode.h

@@ -27,7 +27,7 @@ public:
     {
     }
 
-    intr_ptr::SharedPtr<SHAMapTreeNode>
+    SHAMapTreeNodePtr
     clone(std::uint32_t cowid) const override
     {
         return intr_ptr::makeShared<SHAMapTxPlusMetaLeafNode>(item_, cowid, hash_);

include/xrpl/shamap/TreeNodeCache.h

@@ -11,5 +11,5 @@ using TreeNodeCache = TaggedCache<
     SHAMapTreeNode,
     /*IsKeyCache*/ false,
     intr_ptr::SharedWeakUnionPtr<SHAMapTreeNode>,
-    intr_ptr::SharedPtr<SHAMapTreeNode>>;
+    SHAMapTreeNodePtr>;
 }  // namespace xrpl

include/xrpl/shamap/detail/TaggedPointer.h

@@ -148,7 +148,7 @@ public:
     /** Get the number of elements in each array and a pointer to the start
         of each array.
     */
-    [[nodiscard]] std::tuple<std::uint8_t, SHAMapHash*, intr_ptr::SharedPtr<SHAMapTreeNode>*>
+    [[nodiscard]] std::tuple<std::uint8_t, SHAMapHash*, SHAMapTreeNodePtr*>
     getHashesAndChildren() const;
 
     /** Get the `hashes` array */
@@ -156,7 +156,7 @@ public:
     getHashes() const;
 
     /** Get the `children` array */
-    [[nodiscard]] intr_ptr::SharedPtr<SHAMapTreeNode>*
+    [[nodiscard]] SHAMapTreeNodePtr*
     getChildren() const;
 
     /** Call the `f` callback for all 16 (branchFactor) branches - even if

include/xrpl/shamap/detail/TaggedPointer.ipp

@@ -26,8 +26,7 @@ static_assert(
 // Terminology: A chunk is the memory being allocated from a block. A block
 // contains multiple chunks. This is the terminology the boost documentation
 // uses. Pools use "Simple Segregated Storage" as their storage format.
-constexpr size_t kElementSizeBytes =
-    (sizeof(SHAMapHash) + sizeof(intr_ptr::SharedPtr<SHAMapTreeNode>));
+constexpr size_t kElementSizeBytes = sizeof(SHAMapHash) + sizeof(SHAMapTreeNodePtr);
 
 constexpr size_t kBlockSizeBytes = kilobytes(512);
 
@@ -364,8 +363,7 @@ inline TaggedPointer::TaggedPointer(
                 // keep
                 new (&dstHashes[dstIndex]) SHAMapHash{srcHashes[srcIndex]};
 
-                new (&dstChildren[dstIndex])
-                    intr_ptr::SharedPtr<SHAMapTreeNode>{std::move(srcChildren[srcIndex])};
+                new (&dstChildren[dstIndex]) SHAMapTreeNodePtr{std::move(srcChildren[srcIndex])};
                 ++dstIndex;
                 ++srcIndex;
             }
@@ -376,7 +374,7 @@ inline TaggedPointer::TaggedPointer(
                 if (dstIsDense)
                 {
                     new (&dstHashes[dstIndex]) SHAMapHash{};
-                    new (&dstChildren[dstIndex]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+                    new (&dstChildren[dstIndex]) SHAMapTreeNodePtr{};
                     ++dstIndex;
                 }
             }
@@ -384,7 +382,7 @@ inline TaggedPointer::TaggedPointer(
             {
                 // add
                 new (&dstHashes[dstIndex]) SHAMapHash{};
-                new (&dstChildren[dstIndex]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+                new (&dstChildren[dstIndex]) SHAMapTreeNodePtr{};
                 ++dstIndex;
                 if (srcIsDense)
                 {
@@ -397,7 +395,7 @@ inline TaggedPointer::TaggedPointer(
                 if (dstIsDense)
                 {
                     new (&dstHashes[dstIndex]) SHAMapHash{};
-                    new (&dstChildren[dstIndex]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+                    new (&dstChildren[dstIndex]) SHAMapTreeNodePtr{};
                     ++dstIndex;
                 }
                 if (srcIsDense)
@@ -414,7 +412,7 @@ inline TaggedPointer::TaggedPointer(
         for (int i = dstIndex; i < dstNumAllocated; ++i)
         {
             new (&dstHashes[i]) SHAMapHash{};
-            new (&dstChildren[i]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+            new (&dstChildren[i]) SHAMapTreeNodePtr{};
         }
         *this = std::move(dst);
     }
@@ -433,8 +431,10 @@ inline TaggedPointer::TaggedPointer(
 
     // allocate hashes and children, but do not run constructors
     TaggedPointer newHashesAndChildren{RawAllocateTag{}, toAllocate};
-    SHAMapHash *newHashes = nullptr, *oldHashes = nullptr;
-    intr_ptr::SharedPtr<SHAMapTreeNode>*newChildren = nullptr, *oldChildren = nullptr;
+    SHAMapHash* newHashes = nullptr;
+    SHAMapHash* oldHashes = nullptr;
+    SHAMapTreeNodePtr* newChildren = nullptr;
+    SHAMapTreeNodePtr* oldChildren = nullptr;
     std::uint8_t newNumAllocated = 0;
     // structured bindings can't be captured in c++ 17; use tie instead
     std::tie(newNumAllocated, newHashes, newChildren) = newHashesAndChildren.getHashesAndChildren();
@@ -445,8 +445,7 @@ inline TaggedPointer::TaggedPointer(
         // new arrays are dense, old arrays are sparse
         iterNonEmptyChildIndexes(isBranch, [&](auto branchNum, auto indexNum) {
             new (&newHashes[branchNum]) SHAMapHash{oldHashes[indexNum]};
-            new (&newChildren[branchNum])
-                intr_ptr::SharedPtr<SHAMapTreeNode>{std::move(oldChildren[indexNum])};
+            new (&newChildren[branchNum]) SHAMapTreeNodePtr{std::move(oldChildren[indexNum])};
         });
         // Run the constructors for the remaining elements
         for (int i = 0; i < SHAMapInnerNode::kBranchFactor; ++i)
@@ -454,7 +453,7 @@ inline TaggedPointer::TaggedPointer(
             if (((1 << i) & isBranch) != 0)
                 continue;
             new (&newHashes[i]) SHAMapHash{};
-            new (&newChildren[i]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+            new (&newChildren[i]) SHAMapTreeNodePtr{};
         }
     }
     else
@@ -464,14 +463,14 @@ inline TaggedPointer::TaggedPointer(
         iterNonEmptyChildIndexes(isBranch, [&](auto branchNum, auto indexNum) {
             new (&newHashes[curCompressedIndex]) SHAMapHash{oldHashes[indexNum]};
             new (&newChildren[curCompressedIndex])
-                intr_ptr::SharedPtr<SHAMapTreeNode>{std::move(oldChildren[indexNum])};
+                SHAMapTreeNodePtr{std::move(oldChildren[indexNum])};
             ++curCompressedIndex;
         });
         // Run the constructors for the remaining elements
         for (int i = curCompressedIndex; i < newNumAllocated; ++i)
         {
             new (&newHashes[i]) SHAMapHash{};
-            new (&newChildren[i]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+            new (&newChildren[i]) SHAMapTreeNodePtr{};
         }
     }
 
@@ -485,7 +484,7 @@ inline TaggedPointer::TaggedPointer(std::uint8_t numChildren)
     for (std::size_t i = 0; i < numAllocated; ++i)
     {
         new (&hashes[i]) SHAMapHash{};
-        new (&children[i]) intr_ptr::SharedPtr<SHAMapTreeNode>{};
+        new (&children[i]) SHAMapTreeNodePtr{};
     }
 }
 
@@ -523,14 +522,13 @@ TaggedPointer::isDense() const
     return (tp_ & kTagMask) == kBoundaries.size() - 1;
 }
 
-[[nodiscard]] inline std::tuple<std::uint8_t, SHAMapHash*, intr_ptr::SharedPtr<SHAMapTreeNode>*>
+[[nodiscard]] inline std::tuple<std::uint8_t, SHAMapHash*, SHAMapTreeNodePtr*>
 TaggedPointer::getHashesAndChildren() const
 {
     auto const [tag, ptr] = decode();
     auto const hashes = reinterpret_cast<SHAMapHash*>(ptr);
     std::uint8_t const numAllocated = kBoundaries[tag];
-    auto const children =
-        reinterpret_cast<intr_ptr::SharedPtr<SHAMapTreeNode>*>(hashes + numAllocated);
+    auto const children = reinterpret_cast<SHAMapTreeNodePtr*>(hashes + numAllocated);
     return {numAllocated, hashes, children};
 };
 
@@ -540,7 +538,7 @@ TaggedPointer::getHashes() const
     return reinterpret_cast<SHAMapHash*>(tp_ & kPtrMask);
 };
 
-[[nodiscard]] inline intr_ptr::SharedPtr<SHAMapTreeNode>*
+[[nodiscard]] inline SHAMapTreeNodePtr*
 TaggedPointer::getChildren() const
 {
     auto [unused1, unused2, result] = getHashesAndChildren();

include/xrpl/tx/ApplyContext.h

@@ -93,8 +93,8 @@ public:
         std::function<void(
             uint256 const& key,
             bool isDelete,
-            std::shared_ptr<SLE const> const& before,
-            std::shared_ptr<SLE const> const& after)> const& func);
+            SLE::const_ref before,
+            SLE::const_ref after)> const& func);
 
     void
     destroyXRP(XRPAmount const& fee)
@@ -103,23 +103,7 @@ public:
         view_->rawDestroyXRP(fee);
     }
 
-    /** Applies all invariant checkers one by one.
-
-        @param result the result generated by processing this transaction.
-        @param fee the fee charged for this transaction
-        @return the result code that should be returned for this transaction.
-     */
-    TER
-    checkInvariants(TER const result, XRPAmount const fee);
-
 private:
-    static TER
-    failInvariantCheck(TER const result);
-
-    template <std::size_t... Is>
-    TER
-    checkInvariantsHelper(TER const result, XRPAmount const fee, std::index_sequence<Is...>);
-
     OpenView& base_;
     ApplyFlags flags_;
     std::optional<ApplyViewImpl> view_;

include/xrpl/tx/Transactor.h

@@ -6,6 +6,7 @@
 #include <xrpl/protocol/XRPAmount.h>
 #include <xrpl/tx/ApplyContext.h>
 #include <xrpl/tx/applySteps.h>
+#include <xrpl/tx/invariants/CheckInvariants.h>
 
 #include <utility>
 
@@ -142,19 +143,30 @@ public:
         return ctx_.view();
     }
 
+    /** Whether to run the transaction-specific invariant check.
+     *
+     *  After a fee-claim reset the transaction's effects have been rolled back,
+     *  so only the protocol invariants are meaningful; pass @c Yes to skip the
+     *  transaction-specific check in that case.
+     */
+    enum class SkipTxInvariants : bool { No = false, Yes = true };
+
     /** Check all invariants for the current transaction.
      *
-     *  Runs transaction-specific invariants first (visitInvariantEntry +
-     *  finalizeInvariants), then protocol-level invariants.  Both layers
-     *  always run; the worst failure code is returned.
+     *  Delegates to the free @c xrpl::checkInvariants runner.  Unless @p skip is
+     *  @c SkipTxInvariants::Yes, the transaction-specific adapter is passed so
+     *  both layers share a single walk of the modified ledger entries.
+     *  Protocol faults (tefINVARIANT_FAILED) take priority over transaction
+     *  faults (tecINVARIANT_FAILED).
      *
      *  @param result  the tentative TER from transaction processing.
      *  @param fee     the fee consumed by the transaction.
+     *  @param skip    whether to skip the transaction-specific invariant check.
      *
      *  @return the final TER after all invariant checks.
      */
     [[nodiscard]] TER
-    checkInvariants(TER result, XRPAmount fee);
+    checkInvariants(TER result, XRPAmount fee, SkipTxInvariants skip);
 
     /////////////////////////////////////////////////////
     /*
@@ -263,10 +275,7 @@ protected:
      *                   to detect deletions.
      */
     virtual void
-    visitInvariantEntry(
-        bool isDelete,
-        std::shared_ptr<SLE const> const& before,
-        std::shared_ptr<SLE const> const& after) = 0;
+    visitInvariantEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after) = 0;
 
     /** Check transaction-specific post-conditions after all entries have
      *  been visited.
@@ -368,7 +377,7 @@ private:
         ReadView const& view,
         AccountID const& idSigner,
         AccountID const& idAccount,
-        std::shared_ptr<SLE const> sleAccount,
+        SLE::const_pointer sleAccount,
         beast::Journal const j);
     static NotTEC
     checkMultiSign(
@@ -407,20 +416,34 @@ private:
     static NotTEC
     preflightUniversal(PreflightContext const& ctx);
 
-    /** Check transaction-specific invariants only.
-     *
-     *  Walks every modified ledger entry via visitInvariantEntry, then
-     *  calls finalizeInvariants on the derived transactor.  Returns
-     *  tecINVARIANT_FAILED if any transaction invariant is violated.
-     *
-     *  @param result  the tentative TER from transaction processing.
-     *  @param fee     the fee consumed by the transaction.
-     *
-     *  @return the original result if all invariants pass, or
-     *          tecINVARIANT_FAILED otherwise.
-     */
-    [[nodiscard]] TER
-    checkTransactionInvariants(TER result, XRPAmount fee);
+    /** Bridges the transaction-specific two-phase invariant hooks
+     *  (visitInvariantEntry + finalizeInvariants) into the InvariantCheck
+     *  interface consumed by the free xrpl::checkInvariants runner. */
+    class InvariantCheckAdapter : public InvariantCheck
+    {
+        Transactor& self_;
+
+    public:
+        explicit InvariantCheckAdapter(Transactor& self) : self_(self)
+        {
+        }
+
+        void
+        visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after) override
+        {
+            self_.visitInvariantEntry(isDelete, before, after);
+        }
+
+        [[nodiscard]] bool
+        finalize(
+            STTx const& tx,
+            TER result,
+            XRPAmount fee,
+            ReadView const& view,
+            beast::Journal const& j) const override;
+    };
+
+    InvariantCheckAdapter invariantCheck_{*this};
 };
 
 inline bool

include/xrpl/tx/invariants/AMMInvariant.h

@@ -22,7 +22,7 @@ public:
 
     ValidAMM() = default;
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);

include/xrpl/tx/invariants/CheckInvariants.h

@@ -0,0 +1,129 @@
+#pragma once
+
+#include <xrpl/beast/utility/Journal.h>
+#include <xrpl/ledger/ReadView.h>
+#include <xrpl/protocol/STLedgerEntry.h>
+#include <xrpl/protocol/STTx.h>
+#include <xrpl/protocol/TER.h>
+#include <xrpl/protocol/XRPAmount.h>
+#include <xrpl/tx/ApplyContext.h>
+
+namespace xrpl {
+
+/**
+ * @brief Runtime interface for a transaction-specific invariant check.
+ *
+ * The free @c checkInvariants runner drives two layers of checks over a single
+ * walk of the modified ledger entries:
+ *
+ *  - **Protocol checks** are the concrete types in @c InvariantChecks, held in
+ *    a @c std::tuple and dispatched statically by a compile-time fold (no
+ *    virtual calls).  They are duck-typed against the two-phase contract
+ *    described below; see @c InvariantChecker_PROTOTYPE in InvariantCheck.h.
+ *  - **The transaction-specific check** is injected at runtime through this
+ *    interface, so the runner can call it without depending on the concrete
+ *    transactor type.
+ *
+ * Both layers honour the same two-phase protocol:
+ *
+ * **Phase 1 — state collection** (`visitEntry`)
+ * Called once for each ledger entry created, modified, or deleted by the
+ * transaction.  Implementations accumulate whatever state they need to
+ * evaluate their post-conditions.  Must not throw.
+ *
+ * **Phase 2 — condition evaluation** (`finalize`)
+ * Called once after every modified entry has been visited.  Returns true if
+ * all post-conditions hold, false to fail the transaction.
+ *
+ * ## Rules for implementing `finalize`
+ *
+ * ### Invariants must run regardless of transaction result
+ *
+ * `finalize` MUST perform meaningful checks even when the transaction has
+ * failed (`!isTesSuccess(result)`).  A bug or exploit could cause a failed
+ * transaction to mutate ledger state in unexpected ways; invariants are the
+ * last line of defense.
+ *
+ * The typical pattern: an invariant that expects a domain-specific state
+ * change (e.g. a Vault being created) should expect that change only when
+ * the transaction succeeded.  A failed VaultCreate must not have created a
+ * Vault.
+ *
+ * ### Privilege-gated checks apply to failed transactions too
+ *
+ * Failed transactions carry no privileges.  Any privilege-gated assertion
+ * must therefore also be enforced for failed transactions.
+ */
+class InvariantCheck
+{
+public:
+    virtual ~InvariantCheck() = default;
+
+    /**
+     * @brief Called for each ledger entry modified by the transaction.
+     *
+     * @param isDelete true if the SLE is being deleted.
+     * @param before   the entry's state before the transaction (nullptr for
+     *                 newly created entries).
+     * @param after    the entry's state after the transaction.  For deletions
+     *                 this is the SLE being erased; use @p isDelete rather than
+     *                 `after == nullptr` to detect deletions.
+     */
+    virtual void
+    visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after) = 0;
+
+    /**
+     * @brief Called after all entries have been visited.
+     *
+     * @param tx     the transaction being applied.
+     * @param result the tentative TER result of the transaction.
+     * @param fee    the fee consumed by the transaction.
+     * @param view   read-only view of the ledger after the transaction.
+     * @param j      journal for logging invariant failures.
+     * @return true if all invariants hold; false to fail with
+     *         tecINVARIANT_FAILED / tefINVARIANT_FAILED.
+     */
+    [[nodiscard]] virtual bool
+    finalize(
+        STTx const& tx,
+        TER result,
+        XRPAmount fee,
+        ReadView const& view,
+        beast::Journal const& j) const = 0;
+};
+
+/**
+ * @brief Run all protocol invariant checks plus the transaction-specific check
+ * in a single pass over the modified entries.
+ *
+ * Both layers share one walk of the modified-entry set: @p txCheck's
+ * `visitEntry` accumulates state on the same traversal that drives the
+ * protocol checkers, then both layers' `finalize` run on the complete state.
+ * Protocol faults (tefINVARIANT_FAILED) take precedence over transaction
+ * faults (tecINVARIANT_FAILED).
+ *
+ * Every transaction is guaranteed to supply a @p txCheck (either a real check
+ * or a no-op stub).  The invariant contract requires @c finalize to handle
+ * failed results gracefully, so passing the same @p txCheck after a fee-claim
+ * reset is safe.
+ *
+ * @param ctx     the apply context for the current transaction.
+ * @param result  the tentative TER from transaction processing.
+ * @param fee     the fee consumed by the transaction.
+ * @param txCheck the transaction-specific invariant check.
+ * @return the final TER after all invariant checks.
+ */
+[[nodiscard]] TER
+checkInvariants(
+    ApplyContext& ctx,
+    TER result,
+    XRPAmount fee,
+    std::optional<std::reference_wrapper<InvariantCheck>> txCheck);
+
+[[nodiscard]] inline TER
+checkInvariants(ApplyContext& ctx, TER result, XRPAmount fee)
+{
+    return checkInvariants(ctx, result, fee, std::nullopt);
+}
+
+}  // namespace xrpl

include/xrpl/tx/invariants/FreezeInvariant.h

@@ -22,7 +22,7 @@ class TransfersNotFrozen
 {
     struct BalanceChange
     {
-        std::shared_ptr<SLE const> const line;
+        SLE::const_pointer const line;
         int const balanceChangeSign;
     };
 
@@ -35,37 +35,34 @@ class TransfersNotFrozen
     using ByIssuer = std::map<Issue, IssuerChanges>;
     ByIssuer balanceChanges_;
 
-    std::map<AccountID, std::shared_ptr<SLE const> const> possibleIssuers_;
+    std::map<AccountID, SLE::const_pointer const> possibleIssuers_;
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
 
 private:
     bool
-    isValidEntry(std::shared_ptr<SLE const> const& before, std::shared_ptr<SLE const> const& after);
+    isValidEntry(SLE::const_ref before, SLE::const_ref after);
 
     static STAmount
-    calculateBalanceChange(
-        std::shared_ptr<SLE const> const& before,
-        std::shared_ptr<SLE const> const& after,
-        bool isDelete);
+    calculateBalanceChange(SLE::const_ref before, SLE::const_ref after, bool isDelete);
 
     void
     recordBalance(Issue const& issue, BalanceChange change);
 
     void
-    recordBalanceChanges(std::shared_ptr<SLE const> const& after, STAmount const& balanceChange);
+    recordBalanceChanges(SLE::const_ref after, STAmount const& balanceChange);
 
-    std::shared_ptr<SLE const>
+    SLE::const_pointer
     findIssuer(AccountID const& issuerID, ReadView const& view);
 
     static bool
     validateIssuerChanges(
-        std::shared_ptr<SLE const> const& issuer,
+        SLE::const_ref issuer,
         IssuerChanges const& changes,
         STTx const& tx,
         beast::Journal const& j,

include/xrpl/tx/invariants/InvariantCheck.h

@@ -70,10 +70,7 @@ public:
      * @param after ledger entry after modification by the transaction
      */
     void
-    visitEntry(
-        bool isDelete,
-        std::shared_ptr<SLE const> const& before,
-        std::shared_ptr<SLE const> const& after);
+    visitEntry(bool isDelete, SLE::const_ref before, SLE::const_ref after);
 
     /**
      * @brief called after all ledger entries have been visited to determine
@@ -111,7 +108,7 @@ class TransactionFeeCheck
 {
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     static bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
@@ -131,7 +128,7 @@ class XRPNotCreated
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -151,7 +148,7 @@ class AccountRootsNotDeleted
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -174,11 +171,11 @@ class AccountRootsDeletedClean
     // deleted, it can still be found. After is used specifically for any checks
     // that are expected as part of the deletion, such as zeroing out the
     // balance.
-    std::vector<std::pair<std::shared_ptr<SLE const>, std::shared_ptr<SLE const>>> accountsDeleted_;
+    std::vector<std::pair<SLE::const_pointer, SLE::const_pointer>> accountsDeleted_;
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
@@ -197,7 +194,7 @@ class XRPBalanceChecks
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -214,7 +211,7 @@ class LedgerEntryTypesMatch
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -232,7 +229,7 @@ class NoXRPTrustLines
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -251,7 +248,7 @@ class NoDeepFreezeTrustLinesWithoutFreeze
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -270,7 +267,7 @@ class NoBadOffers
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -286,7 +283,7 @@ class NoZeroEscrow
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -306,7 +303,7 @@ class ValidNewAccountRoot
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -327,7 +324,7 @@ class ValidClawback
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -347,7 +344,7 @@ class ValidPseudoAccounts
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);
@@ -367,7 +364,7 @@ class NoModifiedUnmodifiableFields
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);

include/xrpl/tx/invariants/LoanBrokerInvariant.h

@@ -46,7 +46,7 @@ class ValidLoanBroker
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);

include/xrpl/tx/invariants/LoanInvariant.h

@@ -23,7 +23,7 @@ class ValidLoan
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);

include/xrpl/tx/invariants/MPTInvariant.h

@@ -37,7 +37,7 @@ class ValidMPTIssuance
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -65,7 +65,7 @@ class ValidMPTPayment
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&);

include/xrpl/tx/invariants/NFTInvariant.h

@@ -33,7 +33,7 @@ class ValidNFTokenPage
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;
@@ -61,7 +61,7 @@ class NFTokenCountTracking
 
 public:
     void
-    visitEntry(bool, std::shared_ptr<SLE const> const&, std::shared_ptr<SLE const> const&);
+    visitEntry(bool, SLE::const_ref, SLE::const_ref);
 
     [[nodiscard]] bool
     finalize(STTx const&, TER const, XRPAmount const, ReadView const&, beast::Journal const&) const;