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Simple JNI with Kotlin and Rust
package rust
external fun test(): String
fun main(args: Array<String>): Unit {
System.loadLibrary("hello")
println(test())
}
[package]
name = "hello"
version = "0.1.0"
authors = ["adelnizamutdinov"]
[lib]
crate-type = ["dylib"]
[dependencies]
jni-sys = "0.1.0"
cesu8 = "1.1.0"
extern crate jni_sys;
extern crate cesu8;
use jni_sys::*;
#[derive(Debug)]
struct ExceptionThrown;
#[derive(Copy, Clone)]
struct SafeJNI(*mut jni_sys::JNIEnv);
impl SafeJNI {
fn string(&self, s: &str) -> Result<jni_sys::jstring, ExceptionThrown> {
let s = cvt(s);
let s = unsafe { ((**self.0).NewStringUTF)(self.0, s.as_ptr() as *const _) };
if s.is_null() {
return Err(ExceptionThrown);
}
Ok(s)
}
}
fn cvt(s: &str) -> Vec<u8> {
let mut s = cesu8::to_java_cesu8(s).to_vec();
s.push(0);
s
}
#[no_mangle]
pub extern "C" fn Java_rust_AppKt_test(env: *mut JNIEnv, class: jclass) -> jstring {
SafeJNI(env).string("this is rust mate").unwrap()
}
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