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use jni::objects::{JObject, JValue}; use jni::{sys, JNIEnv, JavaVM, NativeMethod}; use super::Reference; pub trait Object { fn from_reference(reference: Reference) -> Self; fn as_reference(&self) -> &Reference; } pub struct VM(JavaVM); impl VM { pub fn env(&self) -> Env { Env::from(self.0.get_env().unwrap()) } pub(crate) fn internal_clone(&self) -> VM { unsafe { VM(JavaVM::from_raw(self.0.get_java_vm_pointer()).unwrap()) } } } #[derive(Clone)] pub struct Env<'a> { env: JNIEnv<'a>, } static mut SHARED_VM: Option<JavaVM> = None; impl<'a> Env<'a> { pub unsafe fn new(env: *mut sys::JNIEnv) -> Env<'a> { let env = Env { env: JNIEnv::from_raw(env).unwrap(), }; Self::set_vm(env.env.get_java_vm().unwrap()); env } pub fn set_vm(vm: JavaVM) { unsafe { SHARED_VM.replace(vm); } } pub fn current() -> Env<'a> { unsafe { Env { env: SHARED_VM.as_ref().map(|vm| vm.get_env()).unwrap().unwrap(), } .prolong_lifetime() } } pub unsafe fn retain(&self, object: JObject<'a>) -> Reference { Reference { global_ref: self.unwrap(self.env.new_global_ref(object)), vm: VM(self.env.get_java_vm().unwrap()), } } pub unsafe fn prolong_lifetime<'b>(&self) -> Env<'b> { Env { env: std::mem::transmute(self.env.clone()), } } pub unsafe fn call_constructor( &self, name: &str, sig: &str, args: &[JValue<'a>], ) -> JObject<'a> { let class = self.unwrap(self.env.find_class(name)); let args = args.into_iter().map(|&arg| arg.into()).collect::<Vec<_>>(); self.unwrap(self.env.new_object(class, sig, &args)) } pub unsafe fn call_static_method( &self, class: &str, name: &str, sig: &str, args: &[JValue], ) -> JValue<'a> { let class = self.unwrap(self.env.find_class(class)); let args = args.into_iter().map(|&arg| arg.into()).collect::<Vec<_>>(); self.unwrap(self.env.call_static_method(class, name, sig, &args)) } pub unsafe fn call_method( &self, object: JObject<'a>, name: &str, sig: &str, args: &[JValue], ) -> JValue<'a> { let args = args.into_iter().map(|&arg| arg.into()).collect::<Vec<_>>(); self.unwrap(self.env.call_method(object, name, sig, &args)) } pub unsafe fn register_natives( &self, name: &str, methods: impl IntoIterator<Item = NativeMethod>, ) { let class = self.unwrap(self.env.find_class(name)); self.unwrap( self.env.register_native_methods( class, &methods .into_iter() .map(|method| jni::NativeMethod { name: method.name.into(), sig: method.sig.into(), fn_ptr: method.fn_ptr, }) .collect::<Vec<_>>(), ), ); } unsafe fn unwrap<T>(&self, value: jni::errors::Result<T>) -> T { if value.is_err() { let _ = self.env.exception_describe(); } value.unwrap() } pub unsafe fn assume_object(&self, value: JValue<'a>) -> JObject<'a> { match value { JValue::Object(object) => object, _ => unreachable!(), } } pub unsafe fn byte_array(&self, values: &[u8]) -> JObject<'a> { assert!(values.len() <= std::i32::MAX as usize); let array = self.unwrap(self.env.new_byte_array(values.len() as i32)); let elements = self.unwrap(self.env.get_byte_array_elements(array)); std::ptr::copy_nonoverlapping(values.as_ptr(), elements.0 as *mut u8, values.len()); self.unwrap(self.env.release_byte_array_elements( array, elements.0.as_mut().unwrap(), jni::objects::ReleaseMode::NoCopyBack, )); array.into() } } impl<'a> From<JNIEnv<'a>> for Env<'a> { fn from(env: JNIEnv<'a>) -> Self { Env { env } } }