Modularise the wasm module

include/xrpl/tx/transactors/smart_escrow/EscrowWasm.h

@@ -0,0 +1,65 @@
+#pragma once
+
+#include <xrpl/tx/transactors/smart_escrow/HostFunc.h>
+
+#include <string_view>
+#include <vector>
+
+namespace xrpl {
+
+// Escrow-specific WASM constants
+static std::string_view const ESCROW_FUNCTION_NAME = "finish";
+
+/**
+ * Creates WASM imports for smart escrow execution.
+ *
+ * Binds all host functions (ledger access, crypto, float operations, etc.)
+ * to the WASM import table with their associated gas costs.
+ *
+ * @param hfs The host functions implementation to bind
+ * @return Shared pointer to the import vector
+ */
+std::shared_ptr<ImportVec>
+createWasmImport(HostFunctions& hfs);
+
+/**
+ * Runs smart escrow WASM code.
+ *
+ * Executes the specified function in the WASM module with the given parameters
+ * and gas limit.
+ *
+ * @param wasmCode The compiled WASM bytecode
+ * @param hfs Host functions implementation
+ * @param funcName Function to execute (default: "finish")
+ * @param params Parameters to pass to the function
+ * @param gasLimit Maximum gas to consume (-1 for unlimited)
+ * @return EscrowResult on success, TER error code on failure
+ */
+Expected<EscrowResult, TER>
+runEscrowWasm(
+    Bytes const& wasmCode,
+    std::shared_ptr<HostFunctions> const& hfs,
+    std::string_view funcName = ESCROW_FUNCTION_NAME,
+    std::vector<WasmParam> const& params = {},
+    int64_t gasLimit = -1);
+
+/**
+ * Validates smart escrow WASM code during preflight.
+ *
+ * Checks that the WASM module is valid and contains the expected function
+ * signature without actually executing the code.
+ *
+ * @param wasmCode The compiled WASM bytecode
+ * @param hfs Host functions implementation
+ * @param funcName Function to validate (default: "finish")
+ * @param params Parameters to validate against
+ * @return tesSUCCESS if valid, error code otherwise
+ */
+NotTEC
+preflightEscrowWasm(
+    Bytes const& wasmCode,
+    std::shared_ptr<HostFunctions> const& hfs,
+    std::string_view funcName = ESCROW_FUNCTION_NAME,
+    std::vector<WasmParam> const& params = {});
+
+}  // namespace xrpl

src/xrpld/app/wasm/HostFunc.h → include/xrpl/tx/transactors/smart_escrow/HostFunc.h

@@ -1,7 +1,5 @@
 #pragma once
 
-#include <xrpld/app/wasm/ParamsHelper.h>
-
 #include <xrpl/basics/Expected.h>
 #include <xrpl/basics/Slice.h>
 #include <xrpl/beast/utility/Journal.h>
@@ -10,6 +8,7 @@
 #include <xrpl/protocol/Keylet.h>
 #include <xrpl/protocol/TER.h>
 #include <xrpl/protocol/UintTypes.h>
+#include <xrpl/tx/transactors/smart_escrow/ParamsHelper.h>
 
 namespace xrpl {
 

src/xrpld/app/wasm/HostFuncImpl.h → include/xrpl/tx/transactors/smart_escrow/HostFuncImpl.h

@@ -1,8 +1,7 @@
 #pragma once
 
-#include <xrpld/app/wasm/HostFunc.h>
-
 #include <xrpl/tx/ApplyContext.h>
+#include <xrpl/tx/transactors/smart_escrow/HostFunc.h>
 
 namespace xrpl {
 class WasmHostFunctionsImpl : public HostFunctions

src/xrpld/app/wasm/HostFuncWrapper.h → include/xrpl/tx/transactors/smart_escrow/HostFuncWrapper.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <xrpld/app/wasm/WasmiVM.h>
+#include <xrpl/tx/transactors/smart_escrow/wasm/WasmiRuntime.h>
 
 namespace xrpl {
 

src/xrpld/app/wasm/README.md → include/xrpl/tx/transactors/smart_escrow/README.md

@@ -14,11 +14,14 @@ The module follows a layered architecture:
 
 ```
 ┌─────────────────────────────────────────────────────────────┐
-│                 WasmEngine (WasmVM.h)                       │
+│                 EscrowWasm.h                                │
 │         runEscrowWasm(), preflightEscrowWasm()              │
 │              Host function registration                     │
 ├─────────────────────────────────────────────────────────────┤
-│                 WasmiEngine (WasmiVM.h)                     │
+│                 wasm/WasmEngine.h                           │
+│         Singleton facade for WASM runtime execution         │
+├─────────────────────────────────────────────────────────────┤
+│                 wasm/WasmiRuntime.h                         │
 │            Low-level wasmi interpreter integration          │
 ├─────────────────────────────────────────────────────────────┤
 │    HostFuncWrapper          │       HostFuncImpl            │
@@ -31,15 +34,18 @@ The module follows a layered architecture:
 
 ### Key Components
 
-- **`WasmVM.h` / `detail/WasmVM.cpp`** - High-level facade providing:
-  - `WasmEngine` singleton that wraps the underlying WASM interpreter
+- **`EscrowWasm.h` / `EscrowWasm.cpp`** - Escrow-specific WASM functions:
   - `runEscrowWasm()` - Execute WASM code for escrow finish
   - `preflightEscrowWasm()` - Validate WASM code during preflight
   - `createWasmImport()` - Register all host functions
 
-- **`WasmiVM.h` / `detail/WasmiVM.cpp`** - Low-level integration with the
-  [wasmi](https://github.com/wasmi-labs/wasmi) WebAssembly interpreter:
-  - `WasmiEngine` - Manages WASM modules, instances, and execution
+- **`wasm/WasmEngine.h` / `wasm/WasmEngine.cpp`** - Generic WASM engine facade:
+  - `WasmEngine` singleton that wraps the underlying WASM interpreter
+  - WASM constants (`W_ENV`, `W_MEM`, `MAX_PAGES`, etc.)
+
+- **`wasm/WasmiRuntime.h` / `wasm/WasmiRuntime.cpp`** - Low-level integration
+  with the [wasmi](https://github.com/wasmi-labs/wasmi) WebAssembly interpreter:
+  - `WasmiRuntime` - Manages WASM modules, instances, and execution
   - Memory management and gas metering
   - Function invocation and result handling
 
@@ -85,13 +91,13 @@ organized into categories:
 
 For the complete list of available host functions, their WASM names, and gas
 costs, see the [XLS-0102 specification](https://xls.xrpl.org/xls/XLS-0102-wasm-vm.html)
-or `detail/WasmVM.cpp` where they are registered via `WASM_IMPORT_FUNC2` macros.
+or `EscrowWasm.cpp` where they are registered via `WASM_IMPORT_FUNC2` macros.
 For method signatures, see `HostFunc.h`.
 
 ## Gas Model
 
 Each host function has an associated gas cost. The gas cost is specified when
-registering the function in `detail/WasmVM.cpp`:
+registering the function in `EscrowWasm.cpp`:
 
 ```cpp
 WASM_IMPORT_FUNC2(i, getLedgerSqn, "get_ledger_sqn", hfs, 60);
@@ -173,7 +179,7 @@ myNewFunction_wrap(void* env, wasm_val_vec_t const* params, wasm_val_vec_t* resu
 }
 ```
 
-### 6. Register in WasmVM.cpp
+### 6. Register in EscrowWasm.cpp
 
 Add the function registration in `setCommonHostFunctions()` or
 `createWasmImport()`:
@@ -184,6 +190,6 @@ WASM_IMPORT_FUNC2(i, myNewFunction, "my_new_function", hfs, 100);
 ```
 
 > [!IMPORTANT]
-> New host functions MUST be amendment-gated in `WasmVM.cpp`.
+> New host functions MUST be amendment-gated in `EscrowWasm.cpp`.
 > Wrap the registration in an amendment check to ensure the function is only
 > available after the corresponding amendment is enabled on the network.

src/xrpld/app/wasm/WasmVM.h → include/xrpl/tx/transactors/smart_escrow/wasm/WasmEngine.h

@@ -1,11 +1,12 @@
 #pragma once
 
-#include <xrpld/app/wasm/HostFunc.h>
+#include <xrpl/tx/transactors/smart_escrow/HostFunc.h>
 
 #include <string_view>
 
 namespace xrpl {
 
+// Generic WASM constants
 static std::string_view const W_ENV = "env";
 static std::string_view const W_HOST_LIB = "host_lib";
 static std::string_view const W_MEM = "memory";
@@ -16,15 +17,19 @@ static std::string_view const W_ALLOC = "allocate";
 static std::string_view const W_DEALLOC = "deallocate";
 static std::string_view const W_PROC_EXIT = "proc_exit";
 
-static std::string_view const ESCROW_FUNCTION_NAME = "finish";
-
 uint32_t const MAX_PAGES = 128;  // 8MB = 64KB*128
 
-class WasmiEngine;
+class WasmiRuntime;
 
+/**
+ * WasmEngine - Singleton facade for WASM runtime execution.
+ *
+ * This class provides a high-level interface to the underlying Wasmi runtime,
+ * hiding the implementation details and providing a simple API for WASM execution.
+ */
 class WasmEngine
 {
-    std::unique_ptr<WasmiEngine> const impl;
+    std::unique_ptr<WasmiRuntime> const impl;
 
     WasmEngine();
 
@@ -67,24 +72,4 @@ class WasmEngine
     getJournal() const;
 };
 
-////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-std::shared_ptr<ImportVec>
-createWasmImport(HostFunctions& hfs);
-
-Expected<EscrowResult, TER>
-runEscrowWasm(
-    Bytes const& wasmCode,
-    std::shared_ptr<HostFunctions> const& hfs,
-    std::string_view funcName = ESCROW_FUNCTION_NAME,
-    std::vector<WasmParam> const& params = {},
-    int64_t gasLimit = -1);
-
-NotTEC
-preflightEscrowWasm(
-    Bytes const& wasmCode,
-    std::shared_ptr<HostFunctions> const& hfs,
-    std::string_view funcName = ESCROW_FUNCTION_NAME,
-    std::vector<WasmParam> const& params = {});
-
 }  // namespace xrpl

src/xrpld/app/wasm/WasmiVM.h → include/xrpl/tx/transactors/smart_escrow/wasm/WasmiRuntime.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <xrpld/app/wasm/WasmVM.h>
+#include <xrpl/tx/transactors/smart_escrow/wasm/WasmEngine.h>
 
 #include <wasm.h>
 #include <wasmi.h>
@@ -178,7 +178,7 @@ struct ModuleWrapper
     buildImports(StorePtr& s, std::shared_ptr<ImportVec> const& imports);
 };
 
-class WasmiEngine
+class WasmiRuntime
 {
     EnginePtr engine_;
     StorePtr store_;
@@ -192,8 +192,8 @@ class WasmiEngine
     std::shared_ptr<HostFunctions> hfs_;
 
 public:
-    WasmiEngine();
-    ~WasmiEngine() = default;
+    WasmiRuntime();
+    ~WasmiRuntime() = default;
 
     static EnginePtr
     init();

src/xrpld/app/wasm/detail/WasmVM.cpp → src/libxrpl/tx/transactors/smart_escrow/EscrowWasm.cpp

@@ -2,16 +2,9 @@
 // #define DEBUG_OUTPUT 1
 #endif
 
-#include <xrpld/app/wasm/HostFunc.h>
-#include <xrpld/app/wasm/HostFuncWrapper.h>
-#include <xrpld/app/wasm/WasmiVM.h>
-
-#include <xrpl/basics/Log.h>
-#include <xrpl/protocol/AccountID.h>
-#include <xrpl/protocol/Feature.h>
-#include <xrpl/protocol/LedgerFormats.h>
-
-#include <memory>
+#include <xrpl/tx/transactors/smart_escrow/EscrowWasm.h>
+#include <xrpl/tx/transactors/smart_escrow/HostFuncWrapper.h>
+#include <xrpl/tx/transactors/smart_escrow/wasm/WasmEngine.h>
 
 namespace xrpl {
 
@@ -110,12 +103,13 @@ runEscrowWasm(
 {
     //  create VM and set cost limit
     auto& vm = WasmEngine::instance();
-    // vm.initMaxPages(MAX_PAGES);
 
     auto const ret = vm.run(wasmCode, funcName, params, createWasmImport(*hfs), hfs, gasLimit, hfs->getJournal());
 
-    // std::cout << "runEscrowWasm, mod size: " << wasmCode.size()
-    //           << ", gasLimit: " << gasLimit << ", funcName: " << funcName;
+#ifdef DEBUG_OUTPUT
+    std::cout << "runEscrowWasm, mod size: " << wasmCode.size() << ", gasLimit: " << gasLimit
+              << ", funcName: " << funcName;
+#endif
 
     if (!ret)
     {
@@ -140,63 +134,10 @@ preflightEscrowWasm(
 {
     //  create VM and set cost limit
     auto& vm = WasmEngine::instance();
-    // vm.initMaxPages(MAX_PAGES);
 
     auto const ret = vm.check(wasmCode, funcName, params, createWasmImport(*hfs), hfs, hfs->getJournal());
 
     return ret;
 }
 
-////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-WasmEngine::WasmEngine() : impl(std::make_unique<WasmiEngine>())
-{
-}
-
-WasmEngine&
-WasmEngine::instance()
-{
-    static WasmEngine e;
-    return e;
-}
-
-Expected<WasmResult<int32_t>, TER>
-WasmEngine::run(
-    Bytes const& wasmCode,
-    std::string_view funcName,
-    std::vector<WasmParam> const& params,
-    std::shared_ptr<ImportVec> const& imports,
-    std::shared_ptr<HostFunctions> const& hfs,
-    int64_t gasLimit,
-    beast::Journal j)
-{
-    return impl->run(wasmCode, funcName, params, imports, hfs, gasLimit, j);
-}
-
-NotTEC
-WasmEngine::check(
-    Bytes const& wasmCode,
-    std::string_view funcName,
-    std::vector<WasmParam> const& params,
-    std::shared_ptr<ImportVec> const& imports,
-    std::shared_ptr<HostFunctions> const& hfs,
-    beast::Journal j)
-{
-    return impl->check(wasmCode, funcName, params, imports, hfs, j);
-}
-
-void*
-WasmEngine::newTrap(std::string const& msg)
-{
-    return impl->newTrap(msg);
-}
-
-// LCOV_EXCL_START
-beast::Journal
-WasmEngine::getJournal() const
-{
-    return impl->getJournal();
-}
-// LCOV_EXCL_STOP
-
 }  // namespace xrpl

src/xrpld/app/wasm/detail/HostFuncImpl.cpp → src/libxrpl/tx/transactors/smart_escrow/HostFuncImpl.cpp

@@ -1,7 +1,6 @@
-#include <xrpld/app/wasm/HostFuncImpl.h>
-
 #include <xrpl/protocol/STBitString.h>
 #include <xrpl/protocol/digest.h>
+#include <xrpl/tx/transactors/smart_escrow/HostFuncImpl.h>
 
 namespace xrpl {
 

src/xrpld/app/wasm/detail/HostFuncImplFloat.cpp → src/libxrpl/tx/transactors/smart_escrow/HostFuncImplFloat.cpp

@@ -1,7 +1,6 @@
-#include <xrpld/app/wasm/HostFuncImpl.h>
-
 #include <xrpl/protocol/STBitString.h>
 #include <xrpl/protocol/digest.h>
+#include <xrpl/tx/transactors/smart_escrow/HostFunc.h>
 
 #ifdef _DEBUG
 // #define DEBUG_OUTPUT 1

src/xrpld/app/wasm/detail/HostFuncImplGetter.cpp → src/libxrpl/tx/transactors/smart_escrow/HostFuncImplGetter.cpp

@@ -1,7 +1,7 @@
-#include <xrpld/app/wasm/HostFuncImpl.h>
-
+#include <xrpl/protocol/STArray.h>
 #include <xrpl/protocol/STBitString.h>
 #include <xrpl/protocol/digest.h>
+#include <xrpl/tx/transactors/smart_escrow/HostFuncImpl.h>
 
 namespace xrpl {