问题

以下是翻译好的内容：

When i am trying to Run this Function From Dart side it's always giving me this Problem
当我尝试从Dart端运行这个函数时，它总是给我这个问题

memory allocation of 140374366121105 bytes failed
内存分配失败，大小为140374366121105字节
Lost connection to device.
与设备的连接丢失。

But my Source folder is only 2.4 kb
但我的源文件夹只有2.4 kb

Here Is my Rust Function:-
以下是我的Rust函数：

fn copy_dir(source: &Path, destination: &Path) -> io::Result<()> {
    if source.is_dir() {
        fs::create_dir_all(destination)?;
        for entry in fs::read_dir(source)? {
            let entry = entry?;
            let entry_path = entry.path();
            let dest_path = destination.join(entry.file_name());
            if entry_path.is_dir() {
                fs::create_dir_all( &entry_path).unwrap();
            } else {
                fs::copy(&entry_path, &dest_path)?;
            }
        }
    } else {
        fs::copy(source, destination)?;
    }
    Ok(())
}

From dart side i am calling this function like this:-
从Dart端，我是这样调用这个函数的：

`typedef CopyDirFunc = ffi.Void Function(
  ffi.Pointer<Utf8> source,
  ffi.Pointer<Utf8> destination,
);

typedef CopyDir = void Function(
  ffi.Pointer<Utf8> source,
  ffi.Pointer<Utf8> destination,
);

void main(){
final path = Platform.isWindows
              ? 'path\\to\\mylib.dll'
              : '/path/to/mylib.so';
          final dylib = ffi.DynamicLibrary.open(path);
          final copyDirPointer =
              dylib.lookup<ffi.NativeFunction<CopyDirFunc>>('copy_dir');
          final copyDir = copyDirPointer.asFunction<CopyDir>();
          const source = '/path/from/ag_fsm_docs'
          ffi.Pointer<Utf8> utf8Pointer = source.toNativeUtf8();

          const destination = '/path/to/rust_play_folder/Jahid'
          ffi.Pointer<Utf8> utf8Pointer2 = destination.toNativeUtf8();

          copyDir(utf8Pointer, utf8Pointer2);

          calloc.free(utf8Pointer);
          calloc.free(utf8Pointer2);
}`

fn copy_dir(source: &Path, destination: &Path) -> io::Result<()> {
    if source.is_dir() {
        fs::create_dir_all(destination)?;
        for entry in fs::read_dir(source)? {
            let entry = entry?;
            let entry_path = entry.path();
            let dest_path = destination.join(entry.file_name());
            if entry_path.is_dir() {
                fs::create_dir_all( &entry_path).unwrap();
            } else {
                fs::copy(&entry_path, &dest_path)?;
            }
        }
    } else {
        fs::copy(source, destination)?;
    }
    Ok(())
}

`typedef CopyDirFunc = ffi.Void Function(
  ffi.Pointer<Utf8> source,
  ffi.Pointer<Utf8> destination,
);

typedef CopyDir = void Function(
  ffi.Pointer<Utf8> source,
  ffi.Pointer<Utf8> destination,
);

void main(){
final path = Platform.isWindows
              ? 'path\\to\\mylib.dll'
              : '/path/to/mylib.so';
          final dylib = ffi.DynamicLibrary.open(path);
          final copyDirPointer =
              dylib.lookup<ffi.NativeFunction<CopyDirFunc>>('copy_dir');
          final copyDir = copyDirPointer.asFunction<CopyDir>();
          const source = '/path/from/ag_fsm_docs';
          ffi.Pointer<Utf8> utf8Pointer = source.toNativeUtf8();

          const destination = '/path/to/rust_play_folder/Jahid';
          ffi.Pointer<Utf8> utf8Pointer2 = destination.toNativeUtf8();

          copyDir(utf8Pointer, utf8Pointer2);

          calloc.free(utf8Pointer);
          calloc.free(utf8Pointer2);
}`

答案1

得分: 1

你需要还原符号并使用 C 调用约定:

#[no_mangle]
extern fn copy_dir(source: *const u8, destination: *const u8) {…}

你也不应该在 FFI 中使用 Result 和 Path。

#[no_mangle]
extern fn copy_dir(source: *const u8, destination: *const u8) {…}