Initial rust support for erpc #465

etherealjoy · 2025-08-07T12:03:28Z

Pull request

This PR introduce rust support for eRPC

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bug
feature

Describe the pull request

This PR introduce rust support for eRPC, with client and server examples,

To Reproduce

Expected behavior

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OS:
Linux Ubuntu
eRPC Version:

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I read Contribution details and did appropriate actions.
PR code is tested.
PR code is formatted.
Allow edits from maintainers pull request option is set (recommended).

Additional context

Pleae read the crate README_rust.md for more information.
Currently tested only on TCP transport. Serial would be done in the future

Tests include
C++ client to rust server
Java client to rust server
Rust client to Java server
Rust client to C++ server

Copilot

Pull Request Overview

This PR introduces comprehensive Rust support for eRPC, adding a new Rust code generator that produces both client and server bindings for eRPC services. The implementation includes automatic generation of Rust modules from IDL files, async/await support, proper type mapping from eRPC to Rust, and complete interoperability with existing C++ and Java implementations.

Addition of a full Rust code generator (RustGenerator.cpp) with comprehensive IDL-to-Rust type mapping
New Rust example project demonstrating temperature sensor monitoring with cross-language compatibility
Build system integration for Rust template generation across Make, CMake, and Visual Studio

Reviewed Changes

Copilot reviewed 32 out of 34 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
examples/temp_alarm_rust/src/temp_alarm.rs	Generated Rust bindings with client/server traits and implementations
examples/temp_alarm_rust/src/server_impl.rs	Reference server implementation with TCP transport support
examples/temp_alarm_rust/src/main.rs	Command-line application entry point for client/server modes
examples/temp_alarm_rust/src/client_impl.rs	Reference client implementation demonstrating API usage
examples/temp_alarm_rust/Cargo.toml	Rust project configuration with eRPC dependencies
erpcgen/src/RustGenerator.hpp	Rust code generator class declaration with comprehensive type mapping
erpcgen/src/RustGenerator.cpp	Full Rust code generator implementation with async support
erpcgen/src/templates/rust_template.template	Template for generating Rust source files
erpcgen/src/erpcgen.cpp	Integration of Rust generator into CLI tool

Copilot · 2025-08-07T19:18:39Z

examples/temp_alarm_rust/src/temp_alarm.rs

+                        Ok(list)
+                    })()?;
+
+                    let _ = self.service.read_results(results).await;


The result of the async call is being ignored with let _. Consider logging the error or handling it appropriately for better error tracking in production code.

Copilot · 2025-08-07T19:18:40Z

examples/temp_alarm_rust/src/temp_alarm.rs

+
+            let request_data = request_codec.as_bytes().to_vec();
+
+            let _ = self


Similar to the server side, the client is ignoring the result of async operations. Consider proper error handling or at least logging for debugging purposes.

Suggested change

let _ = self

if let Err(e) = self

Copilot · 2025-08-07T19:18:41Z

erpcgen/src/RustGenerator.cpp

+    (void)fnType; // Suppress unused variable warning
+    return format_string(
+        "fn(%s) -> %s", "/* params */",
+        "/* return */"); // TODO: Implement proper function type


The function type handling is incomplete with a TODO comment. This suggests that function pointer types are not fully supported, which could be problematic for callbacks in eRPC.

Suggested change

"/* return */"); // TODO: Implement proper function type

// Build parameter type list

std::vector<std::string> paramTypes;

for (auto param : fnType->getParameters()) {

paramTypes.push_back(getTypeString(param->getDataType()));

}

std::string paramsStr;

if (paramTypes.empty()) {

paramsStr = "";

} else {

paramsStr = paramTypes[0];

for (size_t i = 1; i < paramTypes.size(); ++i) {

paramsStr += ", " + paramTypes[i];

}

}

// Get return type

std::string retType = getTypeString(fnType->getReturnType());

// If return type is void, use ()

if (fnType->getReturnType() && fnType->getReturnType()->getDataType() == DataType::data_type_t::kVoidType) {

retType = "()";

}

return format_string("fn(%s) -> %s", paramsStr.c_str(), retType.c_str());

Copilot · 2025-08-07T19:18:41Z

erpcgen/src/RustGenerator.cpp

+  // In eRPC, enums follow C/C++ convention where the underlying type is int32
+  // This ensures wire compatibility with C++ and Java implementations
+  (void)enumType; // Suppress unused parameter warning
+


[nitpick] The function ignores the enum type parameter and always returns i32. This may not be optimal for enums with small value ranges that could use u8 or u16 for better memory efficiency.

Suggested change

// Use the actual underlying data type from the enum definition if available.

// If not specified, default to i32 for compatibility.

if (enumType && enumType->hasUnderlyingType()) {

// Map the underlying type to the appropriate Rust type string.

BuiltinType::builtin_type_t underlyingType = enumType->getUnderlyingType();

switch (underlyingType) {

case BuiltinType::builtin_type_t::kUInt8Type:

return "u8";

case BuiltinType::builtin_type_t::kUInt16Type:

return "u16";

case BuiltinType::builtin_type_t::kUInt32Type:

return "u32";

case BuiltinType::builtin_type_t::kUInt64Type:

return "u64";

case BuiltinType::builtin_type_t::kInt8Type:

return "i8";

case BuiltinType::builtin_type_t::kInt16Type:

return "i16";

case BuiltinType::builtin_type_t::kInt32Type:

return "i32";

case BuiltinType::builtin_type_t::kInt64Type:

return "i64";

default:

return "i32"; // Fallback for unknown types

}

}

Copilot · 2025-08-07T19:18:41Z

erpcgen/src/RustGenerator.cpp

+        default:
+          code << "                    let " << paramName
+               << " = Default::default(); // TODO: Handle "
+               << builtinType->getName() << "\n";


The default case generates TODO comments in the output code, which indicates incomplete type support. This could lead to compilation errors in generated Rust code.

Suggested change

<< builtinType->getName() << "\n";

throw std::runtime_error(

std::string("Unsupported builtin type in Rust code generation: ") +

builtinType->getName());

Copilot AI review requested due to automatic review settings August 7, 2025 12:03

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etherealjoy force-pushed the add_erpc_rust branch from 25f39a8 to 5f2117d Compare August 7, 2025 14:20

Initial rust support for erpc

d776a55

etherealjoy force-pushed the add_erpc_rust branch from b517ecc to d776a55 Compare August 7, 2025 18:53

etherealjoy requested a review from Copilot August 7, 2025 19:16

Copilot AI reviewed Aug 7, 2025

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Initial rust support for erpc #465

Initial rust support for erpc #465

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		let request_data = request_codec.as_bytes().to_vec();

		let _ = self

-        "/* return */"); // TODO: Implement proper function type
+    // Build parameter type list
+    std::vector<std::string> paramTypes;
+    for (auto param : fnType->getParameters()) {
+      paramTypes.push_back(getTypeString(param->getDataType()));
+    }
+    std::string paramsStr;
+    if (paramTypes.empty()) {
+      paramsStr = "";
+    } else {
+      paramsStr = paramTypes[0];
+      for (size_t i = 1; i < paramTypes.size(); ++i) {
+        paramsStr += ", " + paramTypes[i];
+      }
+    }
+    // Get return type
+    std::string retType = getTypeString(fnType->getReturnType());
+    // If return type is void, use ()
+    if (fnType->getReturnType() && fnType->getReturnType()->getDataType() == DataType::data_type_t::kVoidType) {
+      retType = "()";
+    }
+    return format_string("fn(%s) -> %s", paramsStr.c_str(), retType.c_str());

+  // Use the actual underlying data type from the enum definition if available.
+  // If not specified, default to i32 for compatibility.
+  if (enumType && enumType->hasUnderlyingType()) {
+    // Map the underlying type to the appropriate Rust type string.
+    BuiltinType::builtin_type_t underlyingType = enumType->getUnderlyingType();
+    switch (underlyingType) {
+      case BuiltinType::builtin_type_t::kUInt8Type:
+        return "u8";
+      case BuiltinType::builtin_type_t::kUInt16Type:
+        return "u16";
+      case BuiltinType::builtin_type_t::kUInt32Type:
+        return "u32";
+      case BuiltinType::builtin_type_t::kUInt64Type:
+        return "u64";
+      case BuiltinType::builtin_type_t::kInt8Type:
+        return "i8";
+      case BuiltinType::builtin_type_t::kInt16Type:
+        return "i16";
+      case BuiltinType::builtin_type_t::kInt32Type:
+        return "i32";
+      case BuiltinType::builtin_type_t::kInt64Type:
+        return "i64";
+      default:
+        return "i32"; // Fallback for unknown types
+    }
+  }

-               << builtinType->getName() << "\n";
+          throw std::runtime_error(
+              std::string("Unsupported builtin type in Rust code generation: ") +
+              builtinType->getName());

Initial rust support for erpc #465

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Initial rust support for erpc #465

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etherealjoy commented Aug 7, 2025

Pull request

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Pull Request Overview

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