What's this?

This Repository provide tools to build mobile applications in Rust.
It generate bindings from a Rust package and packaged to android aar or iOS framework. You don't need to write jni or other ffi code with this tool.

Step by step.

Setup rust environment.
Install 'rsbind'. cargo install --git https://github.com/sidneywang/rsbind.git --force -- rsbind
Create a Rust library, which contains two directory, contract and imp. You can put your interface to contract module and implemation to imp module. Expose these two modules in lib.rs.

// such as your code in contract dir as below:
pub trait YourContract {
    fn test_simple(arg1: i32, arg2: String) -> String;
    fn test_callback(arg: Box<Callback>);
    fn test_struct() -> StructSimple;
}

pub trait Callback {
    fn on_callback(arg1: i64, arg2: String);
}

pub struct StructSimple {
    pub arg3: String,
    pub arg4: bool,
}

// Your implementation is as below
pub struct YourImplemetation {}

impl YourContract for YourImplemetation {
    fn test_simple(arg1: i32, arg2: String) -> String {
        format!("Your test_simple result is {}_{}", arg1, arg2)
    }

    fn test_callback(arg: Box<Callback>) {
        arg.on_callback(123i64, "hello callback".to_owned());
    }

    fn test_struct() -> StructSimple {
        StructSimple {
            arg1: "struct".to_owned(),
            arg2: true
        }
    }
}

Run rsbind command as below. Then the generated code will be in _gen directory and aar/framework will be in target directory.

Rsbind usage:

rsbind path-of-project android/ios/all ast/bridge/dest/header/build/all

ast: generate simplified ast files with json format to _gen/ast.
bridge: generate c methods to expose our interface to _gen/[ios/android]_bridge.
dest: generate java/swift wrapper and c header, and then put then into a project(_gen/[ios/android]_dest).
build: build bridge modules and copy output to dest project and then build dest project.
all: run all the steps for binding.

It will generate java files packaged in aar or swift files packaged in framework, then you can integrated them to your android/iOS project and call the functions. For android, you can call like as below:

YourContract.test_callback(new Callback(){
       void on_callback(long arg1, String arg2) {
           // do your things.
       }
})

Swift is very similar.

Configuration

You can create a file named Rsbind.toml to add some configuration.

[android]
rustc_param = ""
arch = ["armv7-linux-androideabi"]
arch_64 = ["aarch64-linux-android"]
arch_x86 = ["i686-linux-android"]
release = true
namespace = "com.afoxer.xxx.ffi"
so_name = "demo"
ext_lib = []
features_def = ["xxxx=[]"]

[ios]
rustc_param = ""
arch_phone = ["armv7-apple-ios"]
arch_simu = ["i386-apple-ios", "x86_64-apple-ios"]
release = true
features_def = []

Supported Types

Parameters: Basic types, Callback, Vec
Return: Basic types, Struct, Vec

supported types in Callback:

Parameters: Basic types, Vec, Struct
Return: Basic types.

TODO: add callback support for return types.

It is different to define a callback and a normal trait. It should contains &self in every callback but not in normal trait.

Callback:

pub trait Callback : Sync {
    fn on_callback(&self, arg1: i32, arg2: String, arg3: bool, arg4: f32, arg5: f64) -> i32;
    fn on_callback2(&self, arg1: bool) -> bool;
    fn on_callback_complex(&self, arg1: StructSimple) -> bool;
    fn on_callback_arg_vec(&self, arg1: Vec<StructSimple>) -> bool;
    fn on_callback_arg_vec_simple(&self, arg1: Vec<String>) -> bool;
}

Normal trait:

pub trait TestContract1 {
    fn test_arg_vec(arg: Vec<String>) -> i32;
    fn test_return_vec(arg: u8) -> Vec<i32>;
    fn test_arg_callback(arg: Box<Callback>) -> u8;
    fn test_bool(arg1: bool) -> bool;
    fn test_struct() -> StructSimple;
    fn test_struct_vec() -> Vec<StructSimple>;
}

简单介绍

该库帮助开发者使用Rust语言来开发Android和iOS应用程序。
方式是通过简单的命令，直接生成iOS的framework以及android的aar, 其中自动生成了Rust接口对应的java绑定和swift绑定代码。省去了开发者自己动手写ffi及其转换代码的繁琐。

使用方式

Rust环境搭建
安装rsbind。cargo install --git https://github.com/sidneywang/rsbind.git --force -- rsbind
创建rust项目，并在项目的src目录下建立两个module，分别是contract和imp，contract用于存放Android/iOS调用的接口，而imp则是接口的实现。并需要在根目录lib.rs下将两个module开放出来。具体可以参考demo。比如像下面这样：

// such as your code in contract dir as below:
pub trait YourContract {
    fn test_simple(arg1: i32, arg2: String) -> String;
    fn test_callback(arg: Box<Callback>);
    fn test_struct() -> StructSimple;
}

pub trait Callback {
    fn on_callback(arg1: i64, arg2: String);
}

pub struct StructSimple {
    pub arg3: String,
    pub arg4: bool,
}

// Your implementation is as below
pub struct YourImplemetation {}

impl YourContract for YourImplemetation {
    fn test_simple(arg1: i32, arg2: String) -> String {
        format!("Your test_simple result is {}_{}", arg1, arg2)
    }

    fn test_callback(arg: Box<Callback>) {
        arg.on_callback(123i64, "hello callback".to_owned());
    }

    fn test_struct() -> StructSimple {
        StructSimple {
            arg1: "struct".to_owned(),
            arg2: true
        }
    }
}

执行rsbind命令(具体如下)，那么在A项目的target目录下就有生成的framework了。如果想要看接口，可以在A项目下_gen/[swift/java]_gen下查看文件。
工具生成的aar或者framework你可以集成到自己的工程中，在android中，你的调用方式类似于这样：

YourContract.test_callback(new Callback(){
       void on_callback(long arg1, String arg2) {
           // do your things.
       }
})

Swift的调用也差不多。

错误解决：执行rsbind，如果有Library not load的错误，在启动项中加入如下该配置即可： export LD_LIBRARY_PATH=$(rustc --print sysroot)/lib:$LD_LIBRARY_PATH

rsbind的使用方式：

rsbind path-of-project android/ios/all ast/bridge/dest/header/build/all

ast：生成简化的ast，并以json保存在_gen/ast中
bridge：生成暴露的c接口，并建立一个module放到_gen/[ios/android]_bridge中
dest: 生成java、swift的wrapper代码以及c的头文件，并将工程放到_gen/[ios/android]_dest中
header：单独诚生c header，并放到_gen/header中
build: 编译bridge模块生成.a或者.so并拷贝到dest工程，然后编译dest工程生成最终产物。
all: 执行所有的步骤，并生成产物。

编译参数配置

在module的根目录，新建Rsbind.toml。

[android]
rustc_param = ""
arch = ["armv7-linux-androideabi"]
arch_64 = ["aarch64-linux-android"]
arch_x86 = ["i686-linux-android"]
release = true
namespace = "com.afoxer.xxx.ffi"
so_name = "demo"
ext_lib = []
features_def = ["xxxx=[]"]

[ios]
rustc_param = ""
arch_phone = ["armv7-apple-ios"]
arch_simu = ["i386-apple-ios", "x86_64-apple-ios"]
release = true
features_def = []

已经支持类型

参数：基本类型，Callback，Vec
返回值：基本类型，一层的struct，Vec

Callback支持的类型

参数：基本类型，Vec，一层的struct
返回值：基本类型

待补充：返回值支持callback。

可以使用callback的getter setter来达到复杂类型的作用。

Callback和普通的类定义不同，callback的每个函数需要有&self 比如：

pub trait Callback : Sync {
    fn on_callback(&self, arg1: i32, arg2: String, arg3: bool, arg4: f32, arg5: f64) -> i32;
    fn on_callback2(&self, arg1: bool) -> bool;
    fn on_callback_complex(&self, arg1: StructSimple) -> bool;
    fn on_callback_arg_vec(&self, arg1: Vec<StructSimple>) -> bool;
    fn on_callback_arg_vec_simple(&self, arg1: Vec<String>) -> bool;
}

而普通的类不需要，比如：

pub trait TestContract1 {
    fn test_arg_vec(arg: Vec<String>) -> i32;
    fn test_return_vec(arg: u8) -> Vec<i32>;
    fn test_arg_callback(arg: Box<Callback>) -> u8;
    fn test_bool(arg1: bool) -> bool;
    fn test_struct() -> StructSimple;
    fn test_struct_vec() -> Vec<StructSimple>;
}

Atul9/rsbind