Hook API Unit Testing

Builds/CMake/RippledCore.cmake

@@ -473,6 +473,7 @@ target_sources (rippled PRIVATE
   src/ripple/app/tx/impl/apply.cpp
   src/ripple/app/tx/impl/applySteps.cpp
   src/ripple/app/hook/impl/applyHook.cpp
+  src/ripple/app/hook/impl/HookAPI.cpp
   src/ripple/app/tx/impl/details/NFTokenUtils.cpp
   #[===============================[
      main sources:

src/ripple/app/hook/HookAPI.h

@@ -0,0 +1,50 @@
+// A decoupled Hook host API helper for programmatic use and testing.
+// Provides selected Hook APIs (emit-related and dependencies) without any
+// dependency on WASM memory. It operates directly on ripple types.
+
+#pragma once
+
+#include <ripple/app/tx/impl/ApplyContext.h>
+#include <ripple/basics/Blob.h>
+#include <ripple/basics/Expected.h>
+#include <ripple/basics/Slice.h>
+#include <ripple/protocol/STTx.h>
+
+#include <ripple/app/misc/Transaction.h>
+#include <cstdint>
+
+namespace hook {
+
+struct HookContext;  // defined in applyHook.h
+
+class HookAPI
+{
+public:
+    explicit HookAPI(HookContext& ctx) : hookCtx(ctx)
+    {
+    }
+
+    // Emit a transaction from the running hook. On success, returns 32-byte
+    // transaction ID bytes (same content written by the wasm host function).
+    ripple::Expected<std::shared_ptr<ripple::Transaction>, std::int64_t>
+    emit(ripple::Slice txBlob);
+
+    // Dependencies (public so callers can compose):
+    // etxn_generation == otxn_generation() + 1
+    std::int64_t
+    etxn_generation() const;
+    std::int64_t
+    etxn_burden() const;
+    std::int64_t
+    etxn_fee_base(ripple::Slice txBlob) const;
+
+    std::int64_t
+    otxn_generation() const;
+    std::int64_t
+    otxn_burden() const;
+
+private:
+    HookContext& hookCtx;
+};
+
+}  // namespace hook

src/ripple/app/hook/applyHook.h

@@ -481,7 +481,6 @@ struct HookResult
     ripple::uint256 const hookHash;
     ripple::uint256 const hookCanEmit;
     ripple::Keylet const accountKeylet;
-    ripple::Keylet const ownerDirKeylet;
     ripple::Keylet const hookKeylet;
     ripple::AccountID const account;
     ripple::AccountID const otxnAccount;

src/ripple/app/hook/impl/HookAPI.cpp

@@ -0,0 +1,440 @@
+// Implementation of decoupled Hook APIs for emit and related helpers.
+
+#include <ripple/app/hook/HookAPI.h>
+#include <ripple/app/hook/applyHook.h>
+#include <ripple/app/ledger/OpenLedger.h>
+#include <ripple/app/misc/Transaction.h>
+#include <ripple/app/tx/apply.h>
+#include <ripple/app/tx/impl/ApplyContext.h>
+#include <ripple/app/tx/impl/Transactor.h>
+#include <ripple/basics/Log.h>
+#include <ripple/protocol/STObject.h>
+#include <ripple/protocol/TxFlags.h>
+#include <ripple/protocol/tokens.h>
+
+namespace hook {
+
+using namespace ripple;
+
+std::int64_t
+HookAPI::otxn_burden() const
+{
+    auto& applyCtx = hookCtx.applyCtx;
+    auto j = applyCtx.app.journal("View");
+
+    if (hookCtx.burden)
+        return hookCtx.burden;
+
+    auto const& tx = applyCtx.tx;
+    if (!tx.isFieldPresent(sfEmitDetails))
+        return 1;
+
+    auto const& pd = const_cast<ripple::STTx&>(tx)
+                         .getField(sfEmitDetails)
+                         .downcast<STObject>();
+
+    if (!pd.isFieldPresent(sfEmitBurden))
+    {
+        JLOG(j.warn())
+            << "HookError[" << HC_ACC()
+            << "]: found sfEmitDetails but sfEmitBurden was not present";
+        return 1;
+    }
+
+    std::uint64_t burden = pd.getFieldU64(sfEmitBurden);
+    burden &= ((1ULL << 63) - 1);
+    hookCtx.burden = burden;
+    return static_cast<std::int64_t>(burden);
+}
+
+std::int64_t
+HookAPI::otxn_generation() const
+{
+    auto& applyCtx = hookCtx.applyCtx;
+    auto j = applyCtx.app.journal("View");
+
+    if (hookCtx.generation)
+        return hookCtx.generation;
+
+    auto const& tx = applyCtx.tx;
+    if (!tx.isFieldPresent(sfEmitDetails))
+        return 0;
+
+    auto const& pd = const_cast<ripple::STTx&>(tx)
+                         .getField(sfEmitDetails)
+                         .downcast<STObject>();
+
+    if (!pd.isFieldPresent(sfEmitGeneration))
+    {
+        JLOG(j.warn())
+            << "HookError[" << HC_ACC()
+            << "]: found sfEmitDetails but sfEmitGeneration was not present";
+        return 0;
+    }
+
+    hookCtx.generation = pd.getFieldU32(sfEmitGeneration);
+    return hookCtx.generation;
+}
+
+std::int64_t
+HookAPI::etxn_generation() const
+{
+    return otxn_generation() + 1;
+}
+
+std::int64_t
+HookAPI::etxn_burden() const
+{
+    if (hookCtx.expected_etxn_count <= -1)
+        return hook_api::PREREQUISITE_NOT_MET;
+
+    std::uint64_t last_burden = static_cast<std::uint64_t>(otxn_burden());
+    std::uint64_t burden =
+        last_burden * static_cast<std::uint64_t>(hookCtx.expected_etxn_count);
+    if (burden < last_burden)
+        return hook_api::FEE_TOO_LARGE;
+    return static_cast<std::int64_t>(burden);
+}
+
+std::int64_t
+HookAPI::etxn_fee_base(ripple::Slice txBlob) const
+{
+    auto& applyCtx = hookCtx.applyCtx;
+    auto j = applyCtx.app.journal("View");
+
+    if (hookCtx.expected_etxn_count <= -1)
+        return hook_api::PREREQUISITE_NOT_MET;
+
+    try
+    {
+        SerialIter sitTrans(txBlob);
+        std::unique_ptr<STTx const> stpTrans =
+            std::make_unique<STTx const>(std::ref(sitTrans));
+        return Transactor::calculateBaseFee(
+                   *(applyCtx.app.openLedger().current()), *stpTrans)
+            .drops();
+    }
+    catch (std::exception const& e)
+    {
+        JLOG(j.trace()) << "HookInfo[" << HC_ACC()
+                        << "]: etxn_fee_base exception: " << e.what();
+        return hook_api::INVALID_TXN;
+    }
+}
+
+ripple::Expected<std::shared_ptr<Transaction>, std::int64_t>
+HookAPI::emit(ripple::Slice txBlob)
+{
+    auto& applyCtx = hookCtx.applyCtx;
+    auto j = applyCtx.app.journal("View");
+    auto& view = applyCtx.view();
+
+    if (hookCtx.expected_etxn_count < 0)
+        return ripple::Unexpected<std::int64_t>(hook_api::PREREQUISITE_NOT_MET);
+
+    if (hookCtx.result.emittedTxn.size() >= hookCtx.expected_etxn_count)
+        return ripple::Unexpected<std::int64_t>(hook_api::TOO_MANY_EMITTED_TXN);
+
+    std::shared_ptr<STTx const> stpTrans;
+    try
+    {
+        SerialIter sit(txBlob);
+        stpTrans = std::make_shared<STTx const>(sit);
+    }
+    catch (std::exception const& e)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC() << "]: Failed " << e.what();
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (isPseudoTx(*stpTrans))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: Attempted to emit pseudo txn.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    ripple::TxType txType = stpTrans->getTxnType();
+
+    ripple::uint256 const& hookCanEmit = hookCtx.result.hookCanEmit;
+    if (!hook::canEmit(txType, hookCanEmit))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: Hook cannot emit this txn.";
+        return ripple::Unexpected<std::uint64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // check the emitted txn is valid
+    /* Emitted TXN rules
+     * 0. Account must match the hook account
+     * 1. Sequence: 0
+     * 2. PubSigningKey: 000000000000000
+     * 3. sfEmitDetails present and valid
+     * 4. No sfTxnSignature
+     * 5. LastLedgerSeq > current ledger, > firstledgerseq & LastLedgerSeq < seq
+     * + 5
+     * 6. FirstLedgerSeq > current ledger
+     * 7. Fee must be correctly high
+     * 8. The generation cannot be higher than 10
+     */
+
+    // rule 0: account must match the hook account
+    if (!stpTrans->isFieldPresent(sfAccount) ||
+        stpTrans->getAccountID(sfAccount) != hookCtx.result.account)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfAccount does not match hook account";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 1: sfSequence must be present and 0
+    if (!stpTrans->isFieldPresent(sfSequence) ||
+        stpTrans->getFieldU32(sfSequence) != 0)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfSequence missing or non-zero";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 2: sfSigningPubKey must be present and 00...00
+    if (!stpTrans->isFieldPresent(sfSigningPubKey))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfSigningPubKey missing";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    auto const pk = stpTrans->getSigningPubKey();
+    if (pk.size() != 33 && pk.size() != 0)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfSigningPubKey present but wrong size";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    for (int i = 0; i < pk.size(); ++i)
+        if (pk[i] != 0)
+        {
+            JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                            << "]: sfSigningPubKey present but non-zero.";
+            return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        }
+
+    // rule 2.a: no signers
+    if (stpTrans->isFieldPresent(sfSigners))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfSigners not allowed in emitted txns.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 2.b: ticketseq cannot be used
+    if (stpTrans->isFieldPresent(sfTicketSequence))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfTicketSequence not allowed in emitted txns.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 2.c sfAccountTxnID not allowed
+    if (stpTrans->isFieldPresent(sfAccountTxnID))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfAccountTxnID not allowed in emitted txns.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 3: sfEmitDetails must be present and valid
+    if (!stpTrans->isFieldPresent(sfEmitDetails))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitDetails missing.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    auto const& emitDetails = const_cast<ripple::STTx&>(*stpTrans)
+                                  .getField(sfEmitDetails)
+                                  .downcast<STObject>();
+
+    if (!emitDetails.isFieldPresent(sfEmitGeneration) ||
+        !emitDetails.isFieldPresent(sfEmitBurden) ||
+        !emitDetails.isFieldPresent(sfEmitParentTxnID) ||
+        !emitDetails.isFieldPresent(sfEmitNonce) ||
+        !emitDetails.isFieldPresent(sfEmitHookHash))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitDetails malformed.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 8: emit generation cannot exceed 10
+    if (emitDetails.getFieldU32(sfEmitGeneration) >= 10)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitGeneration was 10 or more.";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    auto const gen = emitDetails.getFieldU32(sfEmitGeneration);
+    auto const bur = emitDetails.getFieldU64(sfEmitBurden);
+    auto const pTxnID = emitDetails.getFieldH256(sfEmitParentTxnID);
+    auto const nonce = emitDetails.getFieldH256(sfEmitNonce);
+
+    std::optional<ripple::AccountID> callback;
+    if (emitDetails.isFieldPresent(sfEmitCallback))
+        callback = emitDetails.getAccountID(sfEmitCallback);
+
+    auto const& hash = emitDetails.getFieldH256(sfEmitHookHash);
+
+    std::uint32_t gen_proper = static_cast<std::uint32_t>(etxn_generation());
+
+    if (gen != gen_proper)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitGeneration provided in EmitDetails "
+                        << "not correct (" << gen << ") "
+                        << "should be " << gen_proper;
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    std::uint64_t bur_proper = static_cast<std::uint64_t>(etxn_burden());
+    if (bur != bur_proper)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitBurden provided in EmitDetails "
+                        << "was not correct (" << bur << ") "
+                        << "should be " << bur_proper;
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (pTxnID != applyCtx.tx.getTransactionID())
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitParentTxnID provided in EmitDetails"
+                        << "was not correct";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (hookCtx.nonce_used.find(nonce) == hookCtx.nonce_used.end())
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitNonce provided in EmitDetails was not "
+                           "generated by nonce api";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (callback && *callback != hookCtx.result.account)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfEmitCallback account must be the account of "
+                           "the emitting hook";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (hash != hookCtx.result.hookHash)
+    {
+        JLOG(j.trace())
+            << "HookEmit[" << HC_ACC()
+            << "]: sfEmitHookHash must be the hash of the emitting hook";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 4: sfTxnSignature must be absent
+    if (stpTrans->isFieldPresent(sfTxnSignature))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfTxnSignature is present but should not be";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 5: LastLedgerSeq must be present and after current ledger
+    if (!stpTrans->isFieldPresent(sfLastLedgerSequence))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfLastLedgerSequence missing";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    std::uint32_t tx_lls = stpTrans->getFieldU32(sfLastLedgerSequence);
+    std::uint32_t ledgerSeq = view.info().seq;
+    if (tx_lls < ledgerSeq + 1)
+    {
+        JLOG(j.trace())
+            << "HookEmit[" << HC_ACC()
+            << "]: sfLastLedgerSequence invalid (less than next ledger)";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (tx_lls > ledgerSeq + 5)
+    {
+        JLOG(j.trace())
+            << "HookEmit[" << HC_ACC()
+            << "]: sfLastLedgerSequence cannot be greater than current seq + 5";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 6
+    if (!stpTrans->isFieldPresent(sfFirstLedgerSequence) ||
+        stpTrans->getFieldU32(sfFirstLedgerSequence) > tx_lls)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: sfFirstLedgerSequence must be present and <= "
+                           "LastLedgerSequence";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // rule 7 check the emitted txn pays the appropriate fee
+    std::int64_t minfee = etxn_fee_base(txBlob);
+
+    if (minfee < 0)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: Fee could not be calculated";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    if (!stpTrans->isFieldPresent(sfFee))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: Fee missing from emitted tx";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    std::int64_t fee = stpTrans->getFieldAmount(sfFee).xrp().drops();
+    if (fee < minfee)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: Fee less than minimum required";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    std::string reason;
+    auto tpTrans =
+        std::make_shared<Transaction>(stpTrans, reason, applyCtx.app);
+    if (tpTrans->getStatus() != NEW)
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: tpTrans->getStatus() != NEW";
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    // preflight the transaction
+    auto preflightResult = ripple::preflight(
+        applyCtx.app,
+        view.rules(),
+        *stpTrans,
+        ripple::ApplyFlags::tapPREFLIGHT_EMIT,
+        j);
+
+    if (!isTesSuccess(preflightResult.ter))
+    {
+        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
+                        << "]: Transaction preflight failure: "
+                        << preflightResult.ter;
+        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+    }
+
+    return tpTrans;
+}
+
+}  // namespace hook

src/ripple/app/hook/impl/applyHook.cpp

@@ -1,3 +1,4 @@
+#include <ripple/app/hook/HookAPI.h>
 #include <ripple/app/hook/applyHook.h>
 #include <ripple/app/ledger/OpenLedger.h>
 #include <ripple/app/ledger/TransactionMaster.h>
@@ -1237,7 +1238,6 @@ hook::apply(
              .hookHash = hookHash,
              .hookCanEmit = hookCanEmit,
              .accountKeylet = keylet::account(account),
-             .ownerDirKeylet = keylet::ownerDir(account),
              .hookKeylet = keylet::hook(account),
              .account = account,
              .otxnAccount = applyCtx.tx.getAccountID(sfAccount),
@@ -2290,35 +2290,9 @@ DEFINE_HOOK_FUNCTION(int64_t, otxn_slot, uint32_t slot_into)
 // hook invocation
 DEFINE_HOOK_FUNCNARG(int64_t, otxn_burden)
 {
-    HOOK_SETUP();  // populates memory_ctx, memory, memory_length, applyCtx,
+    HOOK_SETUP();
-                   // hookCtx on current stack
+    hook::HookAPI api(hookCtx);
-
+    return api.otxn_burden();
-    if (hookCtx.burden)
-        return hookCtx.burden;
-
-    auto const& tx = applyCtx.tx;
-    if (!tx.isFieldPresent(sfEmitDetails))
-        return 1;  // burden is always 1 if the tx wasn't a emit
-
-    auto const& pd = const_cast<ripple::STTx&>(tx)
-                         .getField(sfEmitDetails)
-                         .downcast<STObject>();
-
-    if (!pd.isFieldPresent(sfEmitBurden))
-    {
-        JLOG(j.warn())
-            << "HookError[" << HC_ACC()
-            << "]: found sfEmitDetails but sfEmitBurden was not present";
-        return 1;
-    }
-
-    uint64_t burden = pd.getFieldU64(sfEmitBurden);
-    burden &=
-        ((1ULL << 63) -
-         1);  // wipe out the two high bits just in case somehow they are set
-    hookCtx.burden = burden;
-    return (int64_t)(burden);
-
     HOOK_TEARDOWN();
 }
 
@@ -2327,32 +2301,9 @@ DEFINE_HOOK_FUNCNARG(int64_t, otxn_burden)
 // hook invocation
 DEFINE_HOOK_FUNCNARG(int64_t, otxn_generation)
 {
-    HOOK_SETUP();  // populates memory_ctx, memory, memory_length, applyCtx,
+    HOOK_SETUP();
-                   // hookCtx on current stack
+    hook::HookAPI api(hookCtx);
-
+    return api.otxn_generation();
-    // cache the result as it will not change for this hook execution
-    if (hookCtx.generation)
-        return hookCtx.generation;
-
-    auto const& tx = applyCtx.tx;
-    if (!tx.isFieldPresent(sfEmitDetails))
-        return 0;  // generation is always 0 if the tx wasn't a emit
-
-    auto const& pd = const_cast<ripple::STTx&>(tx)
-                         .getField(sfEmitDetails)
-                         .downcast<STObject>();
-
-    if (!pd.isFieldPresent(sfEmitGeneration))
-    {
-        JLOG(j.warn())
-            << "HookError[" << HC_ACC()
-            << "]: found sfEmitDetails but sfEmitGeneration was not present";
-        return 0;
-    }
-
-    hookCtx.generation = pd.getFieldU32(sfEmitGeneration);
-    return hookCtx.generation;
-
     HOOK_TEARDOWN();
 }
 
@@ -2360,7 +2311,8 @@ DEFINE_HOOK_FUNCNARG(int64_t, otxn_generation)
 DEFINE_HOOK_FUNCNARG(int64_t, etxn_generation)
 {
     // proxy only, no setup or teardown
-    return otxn_generation(hookCtx, frameCtx) + 1;
+    hook::HookAPI api(hookCtx);
+    return api.etxn_generation();
 }
 
 // Return the current ledger sequence number
@@ -3270,341 +3222,43 @@ DEFINE_HOOK_FUNCTION(
     if (write_len < 32)
         return TOO_SMALL;
 
-    auto& app = hookCtx.applyCtx.app;
+    // Delegate to decoupled HookAPI for emit logic
-
+    hook::HookAPI api(hookCtx);
-    if (hookCtx.expected_etxn_count < 0)
+    ripple::Slice txBlob{
-        return PREREQUISITE_NOT_MET;
+        reinterpret_cast<const void*>(memory + read_ptr), read_len};
-
+    if (auto res = api.emit(txBlob))
-    if (hookCtx.result.emittedTxn.size() >= hookCtx.expected_etxn_count)
-        return TOO_MANY_EMITTED_TXN;
-
-    ripple::Blob blob{memory + read_ptr, memory + read_ptr + read_len};
-
-    std::shared_ptr<STTx const> stpTrans;
-    try
     {
-        stpTrans = std::make_shared<STTx const>(
+        auto const& tpTrans = *res;  // 32 bytes
-            SerialIter{memory + read_ptr, read_len});
+        auto const& txID = tpTrans->getID();
+
+        if (txID.size() > write_len)
+            return TOO_SMALL;
+
+        if (NOT_IN_BOUNDS(write_ptr, txID.size(), memory_length))
+            return OUT_OF_BOUNDS;
+
+        auto const write_txid = [&]() -> int64_t {
+            WRITE_WASM_MEMORY_AND_RETURN(
+                write_ptr,
+                txID.size(),
+                txID.data(),
+                txID.size(),
+                memory,
+                memory_length);
+        };
+
+        int64_t result = write_txid();
+
+        if (result == 32)
+            hookCtx.result.emittedTxn.push(tpTrans);
+
+        return result;
     }
-    catch (std::exception& e)
+    else
     {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC() << "]: Failed " << e.what()
+        return res.error();
-                        << "\n";
-        return EMISSION_FAILURE;
     }
 
-    if (isPseudoTx(*stpTrans))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: Attempted to emit pseudo txn.";
-        return EMISSION_FAILURE;
-    }
-
-    ripple::TxType txType = stpTrans->getTxnType();
-
-    ripple::uint256 const& hookCanEmit = hookCtx.result.hookCanEmit;
-    if (!hook::canEmit(txType, hookCanEmit))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: Hook cannot emit this txn.";
-        return EMISSION_FAILURE;
-    }
-
-    // check the emitted txn is valid
-    /* Emitted TXN rules
-     * 0. Account must match the hook account
-     * 1. Sequence: 0
-     * 2. PubSigningKey: 000000000000000
-     * 3. sfEmitDetails present and valid
-     * 4. No sfTxnSignature
-     * 5. LastLedgerSeq > current ledger, > firstledgerseq & LastLedgerSeq < seq
-     * + 5
-     * 6. FirstLedgerSeq > current ledger
-     * 7. Fee must be correctly high
-     * 8. The generation cannot be higher than 10
-     */
-
-    // rule 0: account must match the hook account
-    if (!stpTrans->isFieldPresent(sfAccount) ||
-        stpTrans->getAccountID(sfAccount) != hookCtx.result.account)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfAccount does not match hook account";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 1: sfSequence must be present and 0
-    if (!stpTrans->isFieldPresent(sfSequence) ||
-        stpTrans->getFieldU32(sfSequence) != 0)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfSequence missing or non-zero";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 2: sfSigningPubKey must be present and 00...00
-    if (!stpTrans->isFieldPresent(sfSigningPubKey))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfSigningPubKey missing";
-        return EMISSION_FAILURE;
-    }
-
-    auto const pk = stpTrans->getSigningPubKey();
-    if (pk.size() != 33 && pk.size() != 0)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfSigningPubKey present but wrong size"
-                        << " expecting 33 bytes";
-        return EMISSION_FAILURE;
-    }
-
-    for (int i = 0; i < pk.size(); ++i)
-        if (pk[i] != 0)
-        {
-            JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                            << "]: sfSigningPubKey present but non-zero.";
-            return EMISSION_FAILURE;
-        }
-
-    // rule 2.a: no signers
-    if (stpTrans->isFieldPresent(sfSigners))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfSigners not allowed in emitted txns.";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 2.b: ticketseq cannot be used
-    if (stpTrans->isFieldPresent(sfTicketSequence))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfTicketSequence not allowed in emitted txns.";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 2.c sfAccountTxnID not allowed
-    if (stpTrans->isFieldPresent(sfAccountTxnID))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfAccountTxnID not allowed in emitted txns.";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 3: sfEmitDetails must be present and valid
-    if (!stpTrans->isFieldPresent(sfEmitDetails))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitDetails missing.";
-        return EMISSION_FAILURE;
-    }
-
-    auto const& emitDetails = const_cast<ripple::STTx&>(*stpTrans)
-                                  .getField(sfEmitDetails)
-                                  .downcast<STObject>();
-
-    if (!emitDetails.isFieldPresent(sfEmitGeneration) ||
-        !emitDetails.isFieldPresent(sfEmitBurden) ||
-        !emitDetails.isFieldPresent(sfEmitParentTxnID) ||
-        !emitDetails.isFieldPresent(sfEmitNonce) ||
-        !emitDetails.isFieldPresent(sfEmitHookHash))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitDetails malformed.";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 8: emit generation cannot exceed 10
-    if (emitDetails.getFieldU32(sfEmitGeneration) >= 10)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitGeneration was 10 or more.";
-        return EMISSION_FAILURE;
-    }
-
-    uint32_t gen = emitDetails.getFieldU32(sfEmitGeneration);
-    uint64_t bur = emitDetails.getFieldU64(sfEmitBurden);
-    ripple::uint256 const& pTxnID = emitDetails.getFieldH256(sfEmitParentTxnID);
-    ripple::uint256 const& nonce = emitDetails.getFieldH256(sfEmitNonce);
-
-    std::optional<ripple::AccountID> callback;
-    if (emitDetails.isFieldPresent(sfEmitCallback))
-        callback = emitDetails.getAccountID(sfEmitCallback);
-
-    auto const& hash = emitDetails.getFieldH256(sfEmitHookHash);
-
-    uint32_t gen_proper = etxn_generation(hookCtx, frameCtx);
-
-    if (gen != gen_proper)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitGeneration provided in EmitDetails "
-                        << "not correct (" << gen << ") "
-                        << "should be " << gen_proper;
-        return EMISSION_FAILURE;
-    }
-
-    uint64_t bur_proper = etxn_burden(hookCtx, frameCtx);
-    if (bur != bur_proper)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitBurden provided in EmitDetails "
-                        << "was not correct (" << bur << ") "
-                        << "should be " << bur_proper;
-        return EMISSION_FAILURE;
-    }
-
-    if (pTxnID != applyCtx.tx.getTransactionID())
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitParentTxnID provided in EmitDetails "
-                        << "was not correct";
-        return EMISSION_FAILURE;
-    }
-
-    if (hookCtx.nonce_used.find(nonce) == hookCtx.nonce_used.end())
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitNonce provided in EmitDetails "
-                        << "was not generated by nonce api";
-        return EMISSION_FAILURE;
-    }
-
-    if (callback && *callback != hookCtx.result.account)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfEmitCallback account must be the account "
-                        << "of the emitting hook";
-        return EMISSION_FAILURE;
-    }
-
-    if (hash != hookCtx.result.hookHash)
-    {
-        JLOG(j.trace())
-            << "HookEmit[" << HC_ACC()
-            << "]: sfEmitHookHash must be the hash of the emitting hook";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 4: sfTxnSignature must be absent
-    if (stpTrans->isFieldPresent(sfTxnSignature))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfTxnSignature is present but should not be";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 5: LastLedgerSeq must be present and after current ledger
-    if (!stpTrans->isFieldPresent(sfLastLedgerSequence))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfLastLedgerSequence missing";
-        return EMISSION_FAILURE;
-    }
-
-    uint32_t tx_lls = stpTrans->getFieldU32(sfLastLedgerSequence);
-    uint32_t ledgerSeq = view.info().seq;
-    if (tx_lls < ledgerSeq + 1)
-    {
-        JLOG(j.trace())
-            << "HookEmit[" << HC_ACC()
-            << "]: sfLastLedgerSequence invalid (less than next ledger)";
-        return EMISSION_FAILURE;
-    }
-
-    if (tx_lls > ledgerSeq + 5)
-    {
-        JLOG(j.trace())
-            << "HookEmit[" << HC_ACC()
-            << "]: sfLastLedgerSequence cannot be greater than current seq + 5";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 6
-    if (!stpTrans->isFieldPresent(sfFirstLedgerSequence) ||
-        stpTrans->getFieldU32(sfFirstLedgerSequence) > tx_lls)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: sfFirstLedgerSequence must be present and "
-                        << "<= LastLedgerSequence";
-        return EMISSION_FAILURE;
-    }
-
-    // rule 7 check the emitted txn pays the appropriate fee
-    int64_t minfee = etxn_fee_base(hookCtx, frameCtx, read_ptr, read_len);
-
-    if (minfee < 0)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: Fee could not be calculated";
-        return EMISSION_FAILURE;
-    }
-
-    if (!stpTrans->isFieldPresent(sfFee))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: Fee missing from emitted tx";
-        return EMISSION_FAILURE;
-    }
-
-    int64_t fee = stpTrans->getFieldAmount(sfFee).xrp().drops();
-    if (fee < minfee)
-    {
-        JLOG(j.trace())
-            << "HookEmit[" << HC_ACC()
-            << "]: Fee on emitted txn is less than the minimum required fee";
-        return EMISSION_FAILURE;
-    }
-
-    std::string reason;
-    auto tpTrans = std::make_shared<Transaction>(stpTrans, reason, app);
-    if (tpTrans->getStatus() != NEW)
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: tpTrans->getStatus() != NEW";
-        return EMISSION_FAILURE;
-    }
-
-    // preflight the transaction
-    auto preflightResult = ripple::preflight(
-        applyCtx.app,
-        applyCtx.view().rules(),
-        *stpTrans,
-        ripple::ApplyFlags::tapPREFLIGHT_EMIT,
-        j);
-
-    if (!isTesSuccess(preflightResult.ter))
-    {
-        JLOG(j.trace()) << "HookEmit[" << HC_ACC()
-                        << "]: Transaction preflight failure: "
-                        << preflightResult.ter;
-        return EMISSION_FAILURE;
-    }
-
-    auto const& txID = tpTrans->getID();
-
-    if (txID.size() > write_len)
-        return TOO_SMALL;
-
-    if (NOT_IN_BOUNDS(write_ptr, txID.size(), memory_length))
-        return OUT_OF_BOUNDS;
-
-    auto const write_txid = [&]() -> int64_t {
-        WRITE_WASM_MEMORY_AND_RETURN(
-            write_ptr,
-            txID.size(),
-            txID.data(),
-            txID.size(),
-            memory,
-            memory_length);
-    };
-
-    int64_t result = write_txid();
-
-    if (result == 32)
-        hookCtx.result.emittedTxn.push(tpTrans);
-
-    return result;
     HOOK_TEARDOWN();
 }
 
@@ -3834,22 +3488,9 @@ DEFINE_HOOK_FUNCTION(int64_t, etxn_reserve, uint32_t count)
 // Compute the burden of an emitted transaction based on a number of factors
 DEFINE_HOOK_FUNCNARG(int64_t, etxn_burden)
 {
-    HOOK_SETUP();  // populates memory_ctx, memory, memory_length, applyCtx,
+    HOOK_SETUP();
-                   // hookCtx on current stack
+    hook::HookAPI api(hookCtx);
-
+    return api.etxn_burden();
-    if (hookCtx.expected_etxn_count <= -1)
-        return PREREQUISITE_NOT_MET;
-
-    uint64_t last_burden = (uint64_t)otxn_burden(
-        hookCtx, frameCtx);  // always non-negative so cast is safe
-
-    uint64_t burden = last_burden * hookCtx.expected_etxn_count;
-    if (burden <
-        last_burden)  // this overflow will never happen but handle it anyway
-        return FEE_TOO_LARGE;
-
-    return burden;
-
     HOOK_TEARDOWN();
 }
 
@@ -4633,36 +4274,13 @@ DEFINE_HOOK_FUNCTION(
     uint32_t read_ptr,
     uint32_t read_len)
 {
-    HOOK_SETUP();  // populates memory_ctx, memory, memory_length, applyCtx,
+    HOOK_SETUP();
-                   // hookCtx on current stack
-
     if (NOT_IN_BOUNDS(read_ptr, read_len, memory_length))
         return OUT_OF_BOUNDS;
-
+    hook::HookAPI api(hookCtx);
-    if (hookCtx.expected_etxn_count <= -1)
+    ripple::Slice tx{
-        return PREREQUISITE_NOT_MET;
+        reinterpret_cast<const void*>(read_ptr + memory), read_len};
-
+    return api.etxn_fee_base(tx);
-    try
-    {
-        ripple::Slice tx{
-            reinterpret_cast<const void*>(read_ptr + memory), read_len};
-
-        SerialIter sitTrans(tx);
-
-        std::unique_ptr<STTx const> stpTrans;
-        stpTrans = std::make_unique<STTx const>(std::ref(sitTrans));
-
-        return Transactor::calculateBaseFee(
-                   *(applyCtx.app.openLedger().current()), *stpTrans)
-            .drops();
-    }
-    catch (std::exception& e)
-    {
-        JLOG(j.trace()) << "HookInfo[" << HC_ACC()
-                        << "]: etxn_fee_base exception: " << e.what();
-        return INVALID_TXN;
-    }
-
     HOOK_TEARDOWN();
 }
 

src/test/app/SetHook_test.cpp

@@ -17,11 +17,19 @@
 */
 //==============================================================================
 #include <ripple/app/hook/Enum.h>
+#include <ripple/app/hook/HookAPI.h>
+#include <ripple/app/hook/applyHook.h>
 #include <ripple/app/ledger/LedgerMaster.h>
+#include <ripple/app/tx/impl/ApplyContext.h>
 #include <ripple/app/tx/impl/SetHook.h>
+#include <ripple/basics/base_uint.h>
 #include <ripple/json/json_reader.h>
 #include <ripple/json/json_writer.h>
+#include <ripple/ledger/OpenView.h>
+#include <ripple/protocol/SField.h>
+#include <ripple/protocol/STAccount.h>
 #include <ripple/protocol/TxFlags.h>
+#include <ripple/protocol/TxFormats.h>
 #include <ripple/protocol/jss.h>
 #include <test/app/Import_json.h>
 #include <test/app/SetHook_wasm.h>
@@ -2431,15 +2439,105 @@ public:
         }
     }
 
+    ApplyContext
+    createApplyContext(jtx::Env& env, OpenView ov, STTx const& tx)
+    {
+        ApplyContext applyCtx{
+            env.app(),
+            ov,
+            tx,
+            tesSUCCESS,
+            env.current()->fees().base,
+            tapNONE,
+            env.journal};
+        return applyCtx;
+    }
+
+    hook::HookContext
+    createHookContext(
+        AccountID const& hookAccount,
+        AccountID const& otxnAccount,
+        hook::HookContext ctx)
+    {
+        hook::HookContext hookCtx{
+            .applyCtx = ctx.applyCtx,
+            .result =
+                {
+                    .hookSetTxnID = uint256(),
+                    .hookHash = uint256(),
+                    .hookCanEmit = uint256(),
+                    .accountKeylet = keylet::account(otxnAccount),
+                    .hookKeylet = keylet::hook(hookAccount),
+                    .account = otxnAccount,
+                    .otxnAccount = otxnAccount,
+                    .hookNamespace = uint256(),
+                    .stateMap = ctx.result.stateMap,
+                    .hookParamOverrides = {},
+                    .hookParams = {{}},
+                    .hookSkips = {uint256{}},
+                },
+            .module = nullptr};
+
+        return hookCtx;
+    }
+
     void
     test_emit(FeatureBitset features)
     {
         testcase("Test float_emit");
         using namespace jtx;
-        Env env{*this, features};
 
         auto const alice = Account{"alice"};
         auto const bob = Account{"bob"};
+
+        {
+            Env env{*this, features};
+
+            STTx invokeTx = STTx(ttINVOKE, [&](STObject& obj) {});
+            OpenView ov{*env.current()};
+            ApplyContext applyCtx = createApplyContext(env, ov, invokeTx);
+
+            hook::HookStateMap stateMap;
+            auto hookCtx = hook::HookContext{
+                .applyCtx = applyCtx,
+                .expected_etxn_count = 1,
+                .nonce_used = {{uint256(0), true}},
+                .result =
+                    {
+                        .account = alice.id(),
+                        .accountKeylet = keylet::account(alice),
+                        .hookKeylet = keylet::hook(alice),
+                        .stateMap = stateMap,
+                        .hookParams = {{}},
+                    },
+            };
+
+            hook::HookAPI api(hookCtx);
+
+            STTx emitTx = STTx(ttINVOKE, [&](STObject& obj) {
+                obj[sfAccount] = alice.id();
+                obj[sfSequence] = 0;
+                obj[sfSigningPubKey] = PublicKey();
+                obj[sfFirstLedgerSequence] = env.closed()->seq() + 1;
+                obj[sfLastLedgerSequence] = env.closed()->seq() + 5;
+                obj[sfFee] = env.closed()->fees().base;
+
+                auto& emitDetails = obj.peekFieldObject(sfEmitDetails);
+                emitDetails[sfEmitGeneration] = 1;
+                emitDetails[sfEmitBurden] = 1;
+                emitDetails[sfEmitParentTxnID] = invokeTx.getTransactionID();
+                emitDetails[sfEmitNonce] = uint256();
+                emitDetails[sfEmitHookHash] = uint256();
+            });
+
+            Serializer s;
+            emitTx.add(s);
+            auto result = api.emit(s.slice());
+            BEAST_EXPECT(result.value()->getID() == emitTx.getTransactionID());
+        }
+
+        Env env{*this, features};
+
         env.fund(XRP(10000), alice);
         env.fund(XRP(10000), bob);