從 Rust 到 Go 的回呼函數

問題內容

我正在嘗試建立從 go 呼叫 rust 函數的可能性，然後所述 rust 函數將函數回調到 go。我使用 cgo 作為 go 和 rust 之間的 ffi 介面。 以下是我的 go 程式碼（src/main.go）：

package main

import (
    "c"
    "fmt"
    "unsafe"
)

/*
#cgo cflags: -i./../lib
#cgo ldflags: -l./../bin -lgo_move -wl,-rpath=./bin
#include "move.h"
*/

//export cosmoscallbackwrapper
func cosmoscallbackwrapper(data *c.uchar, datalen c.int) {
    // convert data to go slice
    godata := c.gobytes(unsafe.pointer(data), datalen)

    // call the actual callback function
    cosmoscallback(godata)
}

// setcosmoscallback sets the callback function to be called by the move vm.
func setcosmoscallback(callback func([]byte)) {
    cosmoscallback = callback
    c.set_cosmos_callback((c.cosmos_callback)(unsafe.pointer(c.cosmoscallbackwrapper)))
}

var cosmoscallback func([]byte)

func main() {
    // create a new move interpreter

    // set the callback function
    setcosmoscallback(func(data []byte) {
        fmt.println("received data from move vm:", data)
        // handle data and call cosmos sdk functions as needed
    })
}

這是我的 rust 程式碼 (src/lib.rs)

use std::os::raw::{c_char, c_int};
use std::ffi::cstring;
use std::sync::mutex;
#[macro_use] extern crate lazy_static;
pub fn main() {
}
pub type cosmoscallback = extern "c" fn(*const c_char, c_int);

lazy_static! {
        static ref callback: mutex<option<cosmoscallback>> = mutex::new(none);
}

#[no_mangle]
pub extern "c" fn set_cosmos_callback(callback: cosmoscallback) {
        let mut cb = callback.lock().unwrap();
        *cb = some(callback);
}
#[no_mangle]
pub extern "c" fn cosmoscallbackwrapper(data: *const c_char, data_len: c_int) {
    let cb = callback.lock().unwrap();
    if let some(callback) = &*cb {
        callback(data, data_len);
    }
}

這是我的 cargo.toml 檔案：

[package]
name = "go-move"
version = "0.1.0"
edition = "2021"

[lib]
crate-type = ["cdylib"]

[dependencies]
libc = "0.2"
lazy_static = "1.4.0"


[workspace]
members = [    ".",]

這是 lib/move.h（共享庫的頭檔）：

#ifndef move_vm_lib_h
#define move_vm_lib_h

#include <stdint.h>
//typedef void (*cosmos_callback)(const unsigned char *data, int data_len);
//void set_cosmos_callback(cosmos_callback callback);

typedef void (*cosmos_callback)(const uint8_t* data, int32_t data_len);

void set_cosmos_callback(cosmos_callback callback);
#endif

這是我的 makefile：

shell := /bin/bash
.phony: build
os = $(shell uname)
clean:
        rm -rf bin
        rm -rf target
build:
        @echo the os is $(os)
        mkdir bin
        cargo build --release
ifeq ($(os),linux)
        cp target/release/libgo_move.so bin/
else
        cp target/release/libgo_move.dylib bin/
endif
        cp -a lib/. bin/
        go build --ldflags="-l./bin -lgo_move" -o bin/main src/main.go
run:
        export ld_library_path=./bin && ./main

檔案結構如下：

src
    main.go
    main.rs
bin
    libgo_move.so (after cargo build)
lib
    move.h
cargo.toml
makefile

運行 make clean build 後，我得到以下輸出：

cp target/release/libgo_move.so bin/
cp -a lib/. bin/
go build -o bin/main  src/main.go
# command-line-arguments
src/main.go:27:59: could not determine kind of name for C.cosmosCallbackWrapper
src/main.go:27:25: could not determine kind of name for C.cosmos_callback
src/main.go:27:2: could not determine kind of name for C.set_cosmos_callback

由於某種原因，它找不到 ffi 函數。

正確答案

這是一個愚蠢的錯誤：

/*
#cgo CFLAGS: -I./../lib
#cgo LDFLAGS: -L./../bin -lgo_move -Wl,-rpath=./bin
#include "move.h"
*/

必須在導入之前進行。僅此而已。

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