Simplify FFIs.

.github/resources/witness-generator/Makefile

@@ -7,19 +7,7 @@ endif
 
 # ---- Common ----
 CXX             := g++
-CXXFLAGS_COMMON := -std=c++11 -O3 -I. -Wno-address-of-packed-member -Dmain=circom_main
-UNAME_S         := $(shell uname -s)
-MACOS_OBJCOPY   := /opt/homebrew/opt/binutils/bin/gobjcopy
-ifeq ($(UNAME_S),Darwin)
-    # On macOS CI we expect GNU objcopy from Homebrew binutils at this exact path.
-    ifeq ($(wildcard $(MACOS_OBJCOPY)),)
-        $(error Missing $(MACOS_OBJCOPY). Install binutils with Homebrew or update OBJCOPY for this environment.)
-    endif
-    OBJCOPY := $(MACOS_OBJCOPY)
-else
-    # On non-macOS targets we assume objcopy is available on PATH.
-    OBJCOPY := objcopy
-endif
+CXXFLAGS_COMMON := -std=c++11 -O3 -I. -Wno-address-of-packed-member -Dmain=circom_main -DCIRCUIT_NAME=$(PROJECT)
 COMMON_SRCS     := main.cpp calcwit.cpp fr.cpp $(PROJECT).cpp
 COMMON_OBJS     := $(COMMON_SRCS:.cpp=.o)
 LIB_ONLY_SRCS   := ffi.cpp
@@ -68,7 +56,6 @@ $(BIN): $(COMMON_OBJS)
 
 $(LIB): $(LIB_OBJS)
 	ar rcs $@ $^
-	$(OBJCOPY) --prefix-symbols=$(PROJECT)_ $@
 
 %.o: %.cpp $(DEPS_HPP)
 	$(CXX) $(CXXFLAGS) -c $< -o $@

src/common.cpp

@@ -1,13 +0,0 @@
-#include "types.hpp"
-
-#include <cstdlib>
-
-extern "C" void free_bytes(Bytes* bytes) {
-    if (bytes == nullptr) {
-        return;
-    }
-
-    free(bytes->data);
-    bytes->data = nullptr;
-    bytes->size = 0;
-}

src/poq/ffi.cpp

@@ -1,4 +1,4 @@
-#include "ffi.hpp"
+#include "poq/ffi.hpp"
 
 #include <string>
 #include <vector>
@@ -15,7 +15,7 @@ using json = nlohmann::json;
 // ---- Forward declarations from circom-generated main.cpp ----
 
 /// This is a forward declaration of circom main(). It's renamed due to UB when calling a main() function.
-/// TODO: Successful path of the function returns nothing despite the int return type.
+/// TODO: Successful path of the function has no explicit return.
 int circom_main(int argc, char* argv[]);
 bool check_valid_number(std::string& s, uint base);
 void json2FrElements(json val, std::vector<FrElement>& vval);
@@ -25,7 +25,6 @@ void qualify_input_list(std::string prefix, json& in, json& in1);
 
 // -------------------------------------------------------------
 
-// ---- File-based entry point (wraps circom-generated main) ----
 template<typename T>
 static Status exceptions_into_status(T&& func) {
     try {
@@ -68,8 +67,8 @@ static Status generate_witness_from_files_impl(const char* dat, const char* inpu
     return status_new(StatusCode_DynError, message.c_str());
 }
 
-extern "C" Status generate_witness_from_files(const char* dat, const char* inputs, const char* output) {
-    const Status status = validate_generate_witness_from_files_input(dat, inputs, output);
+extern "C" Status poq_generate_witness_from_files(const char* dat, const char* inputs, const char* output) {
+    const Status status = validate_generate_witness_from_files_input(dat, inputs, output); // NOLINT: if-init
     if (status_is_error(status)) {
         return status;
     }
@@ -82,13 +81,6 @@ extern "C" Status generate_witness_from_files(const char* dat, const char* input
 // ---- Memory-based entry point ----
 
 static Status validate_witness_input(const WitnessInput* input, const Bytes* output) {
-    if (output == nullptr) {
-        return status_new(StatusCode_InvalidInput, "output is null.");
-    }
-    if (output->data != nullptr) {
-        return status_new(StatusCode_InvalidInput, "output.data is not null.");
-    }
-
     if (input == nullptr) {
         return status_new(StatusCode_InvalidInput, "input is null.");
     }
@@ -101,12 +93,20 @@ static Status validate_witness_input(const WitnessInput* input, const Bytes* out
     if (input->inputs_json == nullptr) {
         return status_new(StatusCode_InvalidInput, "input.inputs_json is null.");
     }
+
+    if (output == nullptr) {
+        return status_new(StatusCode_InvalidInput, "output is null.");
+    }
+    if (output->data != nullptr) {
+        return status_new(StatusCode_InvalidInput, "output.data is not null.");
+    }
+
     return status_ok();
 }
 
 static Status generate_witness_impl(const WitnessInput* input, Bytes* output) {
     // TODO: Implement the actual witness generation logic using the provided input data.
-    const uint8_t dummy_witness[] = {0, 1, 2, 3}; // Placeholder for actual witness data
+    const uint8_t dummy_witness[] = {0, 1, 2, 3};
 
     const size_t witness_size = sizeof(dummy_witness);
     uint8_t* witness_data = static_cast<uint8_t*>(malloc(witness_size));
@@ -121,8 +121,8 @@ static Status generate_witness_impl(const WitnessInput* input, Bytes* output) {
     return status_ok();
 }
 
-extern "C" Status generate_witness(const WitnessInput* input, Bytes* output) {
-    const Status status = validate_witness_input(input, output);
+extern "C" Status poq_generate_witness(const WitnessInput* input, Bytes* output) {
+    const Status status = validate_witness_input(input, output); // NOLINT: if-init
     if (status_is_error(status)) {
         return status;
     }

src/poq/ffi.hpp

@@ -1,16 +1,8 @@
-#ifndef FFI_HPP
-#define FFI_HPP
+#ifndef FFI_POQ_HPP
+#define FFI_POQ_HPP
 
 #include "types.hpp"
 
-/// Inputs for witness generation.
-typedef struct WitnessInput {
-    /// Contents of the circuit's .dat file.
-    const ConstBytes dat;
-    /// Null-terminated JSON string of circuit inputs.
-    const char* inputs_json;
-} WitnessInput;
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -27,7 +19,7 @@ extern "C" {
 ///
 /// On success, returns a `Status` with `StatusCode_Ok` and writes the witness to the specified output file.
 /// On failure, returns a `Status` with an appropriate error code.
-Status generate_witness_from_files(const char* dat, const char* inputs, const char* output);
+Status poq_generate_witness_from_files(const char* dat, const char* inputs, const char* output);
 
 /// Generates a witness from in-memory buffers.
 ///
@@ -41,9 +33,7 @@ Status generate_witness_from_files(const char* dat, const char* inputs, const ch
 /// On success, returns a `Status` with `StatusCode_Ok` and populates `output` with the generated witness bytes. The
 /// caller is responsible for freeing the resources allocated into `output` by this function using `free_bytes`.
 /// On failure, returns a `Status` with an appropriate error code, and `output` will not be modified.
-Status generate_witness(const WitnessInput* input, Bytes* output);
-
-void free_bytes(Bytes* bytes);
+Status poq_generate_witness(const WitnessInput* input, Bytes* output);
 
 #ifdef __cplusplus
 }

src/types.hpp

@@ -3,6 +3,7 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
 
 #define STATUS_MESSAGE_LENGTH 256
@@ -57,6 +58,21 @@ static inline Status status_ok() { return status_from_code(StatusCode_Ok); }
 static inline bool status_is_ok(const Status status) { return status_code_is_ok(status.code); }
 static inline bool status_is_error(const Status status) { return status_code_is_error(status.code); }
 
+/// Inputs for witness generation.
+typedef struct WitnessInput {
+    /// Contents of the circuit's .dat file.
+    const ConstBytes dat;
+    /// Null-terminated JSON string of circuit inputs.
+    const char* inputs_json;
+} WitnessInput;
+
+static inline void free_bytes(Bytes* bytes) {
+    if (bytes == NULL) return;
+    free(bytes->data);
+    bytes->data = NULL;
+    bytes->size = 0;
+}
+
 #ifdef __cplusplus
 }
 #endif