doumanash/dart-sys

Rust bindings to dart sdk

dart-sys

Bindings to dart FFI.

Crate version corresponds to Dart SDK release

Use cases

General requirements

• Build your rust code as cdylib lib

Flutter application

• When building for mobile device, you need to build with correct target (i.e. for android-arm64 your rust target must be aarch64-linux-android)

• Place rust library into android/app/src/main/jniLibs accordingly to your target (i.e. for android-arm64 you need to place it inside arm64-v8a)

• Build flutter application;

• Refer to Dart application for next steps. Flutter embeds your library inside APK so you can refer to it by just library full name.

Dart application

• Dart FFI provides API to load C shared libraries: ffi.DynamicLibrary.open(<path to shared library>);

• Once library successfully loaded, returned object can be used to lookup function pointers.

Given following rust function:

#[no_mangle]
pub unsafe extern "C" fn handle(rd: *const c_char) -> i8 {
    //Do something
    return 0;
}

You can access its pointer in following way

import 'dart:ffi' as ffi;
// External package https://pub.dev/packages/ffi
import 'package:ffi/ffi.dart' as ffiUtils;

typedef NativeFunctionT = ffi.Int8 Function(ffi.Pointer<ffiUtils.Utf8>);
typedef DartFunctionT = int Function(ffi.Pointer<ffiUtils.Utf8>);

final d = ffi.DynamicLibrary.open("my_shared_lib_name.so");
final DartFunctionT sendDataToRust = d.lookupFunction<RustRxNativeFunc, RustRxDartFunc>("handle");

/// Use function to send string data which internally converts it to C compatible char buffer.
void sendNative(DartFunctionT sendDataToRust, String d) {
    final data = d.toNativeUtf8();
    sendDataToRust(data);
    ffiUtils.calloc.free(data);
}

How-to update to new SDK version

1. Update version in Cargo.toml to be equal to desired version of SDK

2. Run cargo build --features download-sources,build-bindings

3. Optionally run rustfmt src/lib.rs to make it pretty

4. Commit and publish

dart-sys's Issues

library not found for -ldart (macos)

如图

build.rs 如下

use std::path::Path;

fn main() {
  let dart_path = Path::new("/usr/local/opt/dart/libexec");
  println!(
    r#"cargo:rustc-link-search=native={}"#,
    dart_path.join("bin").to_str().unwrap()
  );
  println!(r"cargo:rustc-link-lib=dart");
}

No build script to automatically link for embedded dart vm

Hi,

I keep getting this link error:

= note: vm.histy2mu0occs4k.rcgu.o : error LNK2019: unresolved external symbol Dart_VersionString referenced in function _ZN2vm4main17h0ad19c8a20b6b3a7E
...
fatal error LNK1120: 1 unresolved externals

Are these bindings working on your side?