napi-rs/crates/napi/src/threadsafe_function.rs

769 lines
22 KiB
Rust

#![allow(clippy::single_component_path_imports)]
use std::convert::Into;
use std::ffi::CString;
use std::marker::PhantomData;
use std::os::raw::c_void;
use std::ptr;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, RwLock};
use crate::bindgen_runtime::{FromNapiValue, ToNapiValue, TypeName, ValidateNapiValue};
use crate::{check_status, sys, Env, JsError, JsUnknown, Result, Status};
/// ThreadSafeFunction Context object
/// the `value` is the value passed to `call` method
pub struct ThreadSafeCallContext<T: 'static> {
pub env: Env,
pub value: T,
}
#[repr(u8)]
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ThreadsafeFunctionCallMode {
NonBlocking,
Blocking,
}
impl From<ThreadsafeFunctionCallMode> for sys::napi_threadsafe_function_call_mode {
fn from(value: ThreadsafeFunctionCallMode) -> Self {
match value {
ThreadsafeFunctionCallMode::Blocking => sys::ThreadsafeFunctionCallMode::blocking,
ThreadsafeFunctionCallMode::NonBlocking => sys::ThreadsafeFunctionCallMode::nonblocking,
}
}
}
type_level_enum! {
/// Type-level `enum` to express how to feed [`ThreadsafeFunction`] errors to
/// the inner [`JsFunction`].
///
/// ### Context
///
/// For callbacks that expect a `Result`-like kind of input, the convention is
/// to have the callback take an `error` parameter as its first parameter.
///
/// This way receiving a `Result<Args…>` can be modelled as follows:
///
/// - In case of `Err(error)`, feed that `error` entity as the first parameter
/// of the callback;
///
/// - Otherwise (in case of `Ok(_)`), feed `null` instead.
///
/// In pseudo-code:
///
/// ```rust,ignore
/// match result_args {
/// Ok(args) => {
/// let js_null = /* … */;
/// callback.call(
/// // this
/// None,
/// // args…
/// &iter::once(js_null).chain(args).collect::<Vec<_>>(),
/// )
/// },
/// Err(err) => callback.call(None, &[JsError::from(err)]),
/// }
/// ```
///
/// **Note that the `Err` case can stem from a failed conversion from native
/// values to js values when calling the callback!**
///
/// That's why:
///
/// > **[This][`ErrorStrategy::CalleeHandled`] is the default error strategy**.
///
/// In order to opt-out of it, [`ThreadsafeFunction`] has an optional second
/// generic parameter (of "kind" [`ErrorStrategy::T`]) that defines whether
/// this behavior ([`ErrorStrategy::CalleeHandled`]) or a non-`Result` one
/// ([`ErrorStrategy::Fatal`]) is desired.
pub enum ErrorStrategy {
/// Input errors (including conversion errors) are left for the callee to
/// handle:
///
/// The callee receives an extra `error` parameter (the first one), which is
/// `null` if no error occurred, and the error payload otherwise.
CalleeHandled,
/// Input errors (including conversion errors) are deemed fatal:
///
/// they can thus cause a `panic!` or abort the process.
///
/// The callee thus is not expected to have to deal with [that extra `error`
/// parameter][CalleeHandled], which is thus not added.
Fatal,
}
}
struct ThreadsafeFunctionHandle {
raw: sys::napi_threadsafe_function,
aborted: RwLock<bool>,
referred: AtomicBool,
}
unsafe impl Send for ThreadsafeFunctionHandle {}
unsafe impl Sync for ThreadsafeFunctionHandle {}
impl Drop for ThreadsafeFunctionHandle {
fn drop(&mut self) {
let aborted_guard = self
.aborted
.read()
.expect("Threadsafe Function aborted lock failed");
if !*aborted_guard && self.referred.load(Ordering::Acquire) {
let release_status = unsafe {
sys::napi_release_threadsafe_function(self.raw, sys::ThreadsafeFunctionReleaseMode::release)
};
assert!(
release_status == sys::Status::napi_ok,
"Threadsafe Function release failed {}",
Status::from(release_status)
);
}
}
}
#[repr(u8)]
enum ThreadsafeFunctionCallVariant {
Direct,
WithCallback,
}
struct ThreadsafeFunctionCallJsBackData<T> {
data: T,
call_variant: ThreadsafeFunctionCallVariant,
callback: Box<dyn FnOnce(JsUnknown) -> Result<()>>,
}
/// Communicate with the addon's main thread by invoking a JavaScript function from other threads.
///
/// ## Example
/// An example of using `ThreadsafeFunction`:
///
/// ```rust
/// #[macro_use]
/// extern crate napi_derive;
///
/// use std::thread;
///
/// use napi::{
/// threadsafe_function::{
/// ThreadSafeCallContext, ThreadsafeFunctionCallMode, ThreadsafeFunctionReleaseMode,
/// },
/// CallContext, Error, JsFunction, JsNumber, JsUndefined, Result, Status,
/// };
///
/// #[js_function(1)]
/// pub fn test_threadsafe_function(ctx: CallContext) -> Result<JsUndefined> {
/// let func = ctx.get::<JsFunction>(0)?;
///
/// let tsfn =
/// ctx
/// .env
/// .create_threadsafe_function(&func, 0, |ctx: ThreadSafeCallContext<Vec<u32>>| {
/// ctx.value
/// .iter()
/// .map(|v| ctx.env.create_uint32(*v))
/// .collect::<Result<Vec<JsNumber>>>()
/// })?;
///
/// let tsfn_cloned = tsfn.clone();
///
/// thread::spawn(move || {
/// let output: Vec<u32> = vec![0, 1, 2, 3];
/// // It's okay to call a threadsafe function multiple times.
/// tsfn.call(Ok(output.clone()), ThreadsafeFunctionCallMode::Blocking);
/// });
///
/// thread::spawn(move || {
/// let output: Vec<u32> = vec![3, 2, 1, 0];
/// // It's okay to call a threadsafe function multiple times.
/// tsfn_cloned.call(Ok(output.clone()), ThreadsafeFunctionCallMode::NonBlocking);
/// });
///
/// ctx.env.get_undefined()
/// }
/// ```
pub struct ThreadsafeFunction<T: 'static, ES: ErrorStrategy::T = ErrorStrategy::CalleeHandled> {
handle: Arc<ThreadsafeFunctionHandle>,
_phantom: PhantomData<(T, ES)>,
}
impl<T: 'static, ES: ErrorStrategy::T> Clone for ThreadsafeFunction<T, ES> {
fn clone(&self) -> Self {
let aborted_guard = self
.handle
.aborted
.read()
.expect("Threadsafe Function aborted lock failed");
if *aborted_guard {
panic!("ThreadsafeFunction was aborted, can not clone it");
}
Self {
handle: self.handle.clone(),
_phantom: PhantomData,
}
}
}
impl<T: ToNapiValue + 'static, ES: ErrorStrategy::T> FromNapiValue for ThreadsafeFunction<T, ES> {
unsafe fn from_napi_value(env: sys::napi_env, napi_val: sys::napi_value) -> Result<Self> {
Self::create(env, napi_val, 0, |ctx| Ok(vec![ctx.value]))
}
}
impl<T: 'static, ES: ErrorStrategy::T> ThreadsafeFunction<T, ES> {
/// See [napi_create_threadsafe_function](https://nodejs.org/api/n-api.html#n_api_napi_create_threadsafe_function)
/// for more information.
pub(crate) fn create<
V: ToNapiValue,
R: 'static + Send + FnMut(ThreadSafeCallContext<T>) -> Result<Vec<V>>,
>(
env: sys::napi_env,
func: sys::napi_value,
max_queue_size: usize,
callback: R,
) -> Result<Self> {
let mut async_resource_name = ptr::null_mut();
let s = "napi_rs_threadsafe_function";
let len = s.len();
let s = CString::new(s)?;
check_status!(unsafe {
sys::napi_create_string_utf8(env, s.as_ptr(), len, &mut async_resource_name)
})?;
let mut raw_tsfn = ptr::null_mut();
let callback_ptr = Box::into_raw(Box::new(callback));
check_status!(unsafe {
sys::napi_create_threadsafe_function(
env,
func,
ptr::null_mut(),
async_resource_name,
max_queue_size,
1,
ptr::null_mut(),
Some(thread_finalize_cb::<T, V, R>),
callback_ptr.cast(),
Some(call_js_cb::<T, V, R, ES>),
&mut raw_tsfn,
)
})?;
Ok(ThreadsafeFunction {
handle: Arc::new(ThreadsafeFunctionHandle {
raw: raw_tsfn,
aborted: RwLock::new(false),
referred: AtomicBool::new(true),
}),
_phantom: PhantomData,
})
}
/// See [napi_ref_threadsafe_function](https://nodejs.org/api/n-api.html#n_api_napi_ref_threadsafe_function)
/// for more information.
///
/// "ref" is a keyword so that we use "refer" here.
pub fn refer(&mut self, env: &Env) -> Result<()> {
let aborted_guard = self
.handle
.aborted
.read()
.expect("Threadsafe Function aborted lock failed");
if !*aborted_guard && !self.handle.referred.load(Ordering::Acquire) {
check_status!(unsafe { sys::napi_ref_threadsafe_function(env.0, self.handle.raw) })?;
self.handle.referred.store(true, Ordering::Release);
}
Ok(())
}
/// See [napi_unref_threadsafe_function](https://nodejs.org/api/n-api.html#n_api_napi_unref_threadsafe_function)
/// for more information.
pub fn unref(&mut self, env: &Env) -> Result<()> {
let aborted_guard = self
.handle
.aborted
.read()
.expect("Threadsafe Function aborted lock failed");
if !*aborted_guard && self.handle.referred.load(Ordering::Acquire) {
check_status!(unsafe { sys::napi_unref_threadsafe_function(env.0, self.handle.raw) })?;
self.handle.referred.store(false, Ordering::Release);
}
Ok(())
}
pub fn aborted(&self) -> bool {
let aborted_guard = self
.handle
.aborted
.read()
.expect("Threadsafe Function aborted lock failed");
*aborted_guard
}
pub fn abort(self) -> Result<()> {
let mut aborted_guard = self
.handle
.aborted
.write()
.expect("Threadsafe Function aborted lock failed");
if !*aborted_guard {
check_status!(unsafe {
sys::napi_release_threadsafe_function(
self.handle.raw,
sys::ThreadsafeFunctionReleaseMode::abort,
)
})?;
*aborted_guard = true;
}
Ok(())
}
/// Get the raw `ThreadSafeFunction` pointer
pub fn raw(&self) -> sys::napi_threadsafe_function {
self.handle.raw
}
}
impl<T: 'static> ThreadsafeFunction<T, ErrorStrategy::CalleeHandled> {
/// See [napi_call_threadsafe_function](https://nodejs.org/api/n-api.html#n_api_napi_call_threadsafe_function)
/// for more information.
pub fn call(&self, value: Result<T>, mode: ThreadsafeFunctionCallMode) -> Status {
unsafe {
sys::napi_call_threadsafe_function(
self.handle.raw,
Box::into_raw(Box::new(value.map(|data| {
ThreadsafeFunctionCallJsBackData {
data,
call_variant: ThreadsafeFunctionCallVariant::Direct,
callback: Box::new(|_d: JsUnknown| Ok(())),
}
})))
.cast(),
mode.into(),
)
}
.into()
}
pub fn call_with_return_value<D: FromNapiValue, F: 'static + FnOnce(D) -> Result<()>>(
&self,
value: Result<T>,
mode: ThreadsafeFunctionCallMode,
cb: F,
) -> Status {
unsafe {
sys::napi_call_threadsafe_function(
self.handle.raw,
Box::into_raw(Box::new(value.map(|data| {
ThreadsafeFunctionCallJsBackData {
data,
call_variant: ThreadsafeFunctionCallVariant::WithCallback,
callback: Box::new(move |d: JsUnknown| {
D::from_napi_value(d.0.env, d.0.value).and_then(cb)
}),
}
})))
.cast(),
mode.into(),
)
}
.into()
}
#[cfg(feature = "tokio_rt")]
pub async fn call_async<D: 'static + FromNapiValue>(&self, value: Result<T>) -> Result<D> {
let (sender, receiver) = tokio::sync::oneshot::channel::<D>();
check_status!(unsafe {
sys::napi_call_threadsafe_function(
self.handle.raw,
Box::into_raw(Box::new(value.map(|data| {
ThreadsafeFunctionCallJsBackData {
data,
call_variant: ThreadsafeFunctionCallVariant::WithCallback,
callback: Box::new(move |d: JsUnknown| {
D::from_napi_value(d.0.env, d.0.value).and_then(move |d| {
sender.send(d).map_err(|_| {
crate::Error::from_reason("Failed to send return value to tokio sender")
})
})
}),
}
})))
.cast(),
ThreadsafeFunctionCallMode::NonBlocking.into(),
)
})?;
receiver
.await
.map_err(|err| crate::Error::new(Status::GenericFailure, format!("{}", err)))
}
}
impl<T: 'static> ThreadsafeFunction<T, ErrorStrategy::Fatal> {
/// See [napi_call_threadsafe_function](https://nodejs.org/api/n-api.html#n_api_napi_call_threadsafe_function)
/// for more information.
pub fn call(&self, value: T, mode: ThreadsafeFunctionCallMode) -> Status {
unsafe {
sys::napi_call_threadsafe_function(
self.handle.raw,
Box::into_raw(Box::new(ThreadsafeFunctionCallJsBackData {
data: value,
call_variant: ThreadsafeFunctionCallVariant::Direct,
callback: Box::new(|_d: JsUnknown| Ok(())),
}))
.cast(),
mode.into(),
)
}
.into()
}
pub fn call_with_return_value<D: FromNapiValue, F: 'static + FnOnce(D) -> Result<()>>(
&self,
value: T,
mode: ThreadsafeFunctionCallMode,
cb: F,
) -> Status {
unsafe {
sys::napi_call_threadsafe_function(
self.handle.raw,
Box::into_raw(Box::new(ThreadsafeFunctionCallJsBackData {
data: value,
call_variant: ThreadsafeFunctionCallVariant::WithCallback,
callback: Box::new(move |d: JsUnknown| {
D::from_napi_value(d.0.env, d.0.value).and_then(cb)
}),
}))
.cast(),
mode.into(),
)
}
.into()
}
#[cfg(feature = "tokio_rt")]
pub async fn call_async<D: 'static + FromNapiValue>(&self, value: T) -> Result<D> {
let (sender, receiver) = tokio::sync::oneshot::channel::<D>();
check_status!(unsafe {
sys::napi_call_threadsafe_function(
self.handle.raw,
Box::into_raw(Box::new(ThreadsafeFunctionCallJsBackData {
data: value,
call_variant: ThreadsafeFunctionCallVariant::WithCallback,
callback: Box::new(move |d: JsUnknown| {
D::from_napi_value(d.0.env, d.0.value).and_then(move |d| {
sender.send(d).map_err(|_| {
crate::Error::from_reason("Failed to send return value to tokio sender")
})
})
}),
}))
.cast(),
ThreadsafeFunctionCallMode::NonBlocking.into(),
)
})?;
receiver
.await
.map_err(|err| crate::Error::new(Status::GenericFailure, format!("{}", err)))
}
}
#[allow(unused_variables)]
unsafe extern "C" fn thread_finalize_cb<T: 'static, V: ToNapiValue, R>(
env: sys::napi_env,
finalize_data: *mut c_void,
finalize_hint: *mut c_void,
) where
R: 'static + Send + FnMut(ThreadSafeCallContext<T>) -> Result<Vec<V>>,
{
// cleanup
drop(unsafe { Box::<R>::from_raw(finalize_hint.cast()) });
}
unsafe extern "C" fn call_js_cb<T: 'static, V: ToNapiValue, R, ES>(
raw_env: sys::napi_env,
js_callback: sys::napi_value,
context: *mut c_void,
data: *mut c_void,
) where
R: 'static + Send + FnMut(ThreadSafeCallContext<T>) -> Result<Vec<V>>,
ES: ErrorStrategy::T,
{
// env and/or callback can be null when shutting down
if raw_env.is_null() || js_callback.is_null() {
return;
}
let ctx: &mut R = unsafe { Box::leak(Box::from_raw(context.cast())) };
let val = unsafe {
match ES::VALUE {
ErrorStrategy::CalleeHandled::VALUE => {
*Box::<Result<ThreadsafeFunctionCallJsBackData<T>>>::from_raw(data.cast())
}
ErrorStrategy::Fatal::VALUE => Ok(*Box::<ThreadsafeFunctionCallJsBackData<T>>::from_raw(
data.cast(),
)),
}
};
let mut recv = ptr::null_mut();
unsafe { sys::napi_get_undefined(raw_env, &mut recv) };
let ret = val.and_then(|v| {
(ctx)(ThreadSafeCallContext {
env: unsafe { Env::from_raw(raw_env) },
value: v.data,
})
.map(|ret| (ret, v.call_variant, v.callback))
});
// Follow async callback conventions: https://nodejs.org/en/knowledge/errors/what-are-the-error-conventions/
// Check if the Result is okay, if so, pass a null as the first (error) argument automatically.
// If the Result is an error, pass that as the first argument.
let status = match ret {
Ok((values, call_variant, callback)) => {
let values = values
.into_iter()
.map(|v| unsafe { ToNapiValue::to_napi_value(raw_env, v) });
let args: Result<Vec<sys::napi_value>> = if ES::VALUE == ErrorStrategy::CalleeHandled::VALUE {
let mut js_null = ptr::null_mut();
unsafe { sys::napi_get_null(raw_env, &mut js_null) };
::core::iter::once(Ok(js_null)).chain(values).collect()
} else {
values.collect()
};
let mut return_value = ptr::null_mut();
let status = match args {
Ok(args) => unsafe {
sys::napi_call_function(
raw_env,
recv,
js_callback,
args.len(),
args.as_ptr(),
&mut return_value,
)
},
Err(e) => match ES::VALUE {
ErrorStrategy::Fatal::VALUE => unsafe {
sys::napi_fatal_exception(raw_env, JsError::from(e).into_value(raw_env))
},
ErrorStrategy::CalleeHandled::VALUE => unsafe {
sys::napi_call_function(
raw_env,
recv,
js_callback,
1,
[JsError::from(e).into_value(raw_env)].as_mut_ptr(),
&mut return_value,
)
},
},
};
if let ThreadsafeFunctionCallVariant::WithCallback = call_variant {
if let Err(err) = callback(JsUnknown(crate::Value {
env: raw_env,
value: return_value,
value_type: crate::ValueType::Unknown,
})) {
let message = format!(
"Failed to convert return value in ThreadsafeFunction callback into Rust value: {}",
err
);
let message_length = message.len();
unsafe {
sys::napi_fatal_error(
"threadsafe_function.rs:573\0".as_ptr().cast(),
26,
CString::new(message).unwrap().into_raw(),
message_length,
)
};
}
}
status
}
Err(e) if ES::VALUE == ErrorStrategy::Fatal::VALUE => unsafe {
sys::napi_fatal_exception(raw_env, JsError::from(e).into_value(raw_env))
},
Err(e) => unsafe {
sys::napi_call_function(
raw_env,
recv,
js_callback,
1,
[JsError::from(e).into_value(raw_env)].as_mut_ptr(),
ptr::null_mut(),
)
},
};
if status == sys::Status::napi_ok {
return;
}
if status == sys::Status::napi_pending_exception {
let mut error_result = ptr::null_mut();
assert_eq!(
unsafe { sys::napi_get_and_clear_last_exception(raw_env, &mut error_result) },
sys::Status::napi_ok
);
// When shutting down, napi_fatal_exception sometimes returns another exception
let stat = unsafe { sys::napi_fatal_exception(raw_env, error_result) };
assert!(stat == sys::Status::napi_ok || stat == sys::Status::napi_pending_exception);
} else {
let error_code: Status = status.into();
let error_code_string = format!("{:?}", error_code);
let mut error_code_value = ptr::null_mut();
assert_eq!(
unsafe {
sys::napi_create_string_utf8(
raw_env,
error_code_string.as_ptr() as *const _,
error_code_string.len(),
&mut error_code_value,
)
},
sys::Status::napi_ok,
);
let error_msg = "Call JavaScript callback failed in thread safe function";
let mut error_msg_value = ptr::null_mut();
assert_eq!(
unsafe {
sys::napi_create_string_utf8(
raw_env,
error_msg.as_ptr() as *const _,
error_msg.len(),
&mut error_msg_value,
)
},
sys::Status::napi_ok,
);
let mut error_value = ptr::null_mut();
assert_eq!(
unsafe {
sys::napi_create_error(raw_env, error_code_value, error_msg_value, &mut error_value)
},
sys::Status::napi_ok,
);
assert_eq!(
unsafe { sys::napi_fatal_exception(raw_env, error_value) },
sys::Status::napi_ok
);
}
}
/// Helper
macro_rules! type_level_enum {(
$( #[doc = $doc:tt] )*
$pub:vis
enum $EnumName:ident {
$(
$( #[doc = $doc_variant:tt] )*
$Variant:ident
),* $(,)?
}
) => (type_level_enum! { // This requires the macro to be in scope when called.
with_docs! {
$( #[doc = $doc] )*
///
/// ### Type-level `enum`
///
/// Until `const_generics` can handle custom `enum`s, this pattern must be
/// implemented at the type level.
///
/// We thus end up with:
///
/// ```rust,ignore
/// #[type_level_enum]
#[doc = ::core::concat!(
" enum ", ::core::stringify!($EnumName), " {",
)]
$(
#[doc = ::core::concat!(
" ", ::core::stringify!($Variant), ",",
)]
)*
#[doc = " }"]
/// ```
///
#[doc = ::core::concat!(
"With [`", ::core::stringify!($EnumName), "::T`](#reexports) \
being the type-level \"enum type\":",
)]
///
/// ```rust,ignore
#[doc = ::core::concat!(
"<Param: ", ::core::stringify!($EnumName), "::T>"
)]
/// ```
}
#[allow(warnings)]
$pub mod $EnumName {
#[doc(no_inline)]
pub use $EnumName as T;
super::type_level_enum! {
with_docs! {
#[doc = ::core::concat!(
"See [`", ::core::stringify!($EnumName), "`]\
[super::", ::core::stringify!($EnumName), "]"
)]
}
pub trait $EnumName : __sealed::$EnumName + ::core::marker::Sized + 'static {
const VALUE: __value::$EnumName;
}
}
mod __sealed { pub trait $EnumName {} }
mod __value {
#[derive(Debug, PartialEq, Eq)]
pub enum $EnumName { $( $Variant ),* }
}
$(
$( #[doc = $doc_variant] )*
pub enum $Variant {}
impl __sealed::$EnumName for $Variant {}
impl $EnumName for $Variant {
const VALUE: __value::$EnumName = __value::$EnumName::$Variant;
}
impl $Variant {
pub const VALUE: __value::$EnumName = __value::$EnumName::$Variant;
}
)*
}
});(
with_docs! {
$( #[doc = $doc:expr] )*
}
$item:item
) => (
$( #[doc = $doc] )*
$item
)}
use type_level_enum;
pub struct UnknownReturnValue;
impl TypeName for UnknownReturnValue {
fn type_name() -> &'static str {
"UnknownReturnValue"
}
fn value_type() -> crate::ValueType {
crate::ValueType::Unknown
}
}
impl ValidateNapiValue for UnknownReturnValue {}
impl FromNapiValue for UnknownReturnValue {
unsafe fn from_napi_value(_env: sys::napi_env, _napi_val: sys::napi_value) -> Result<Self> {
Ok(UnknownReturnValue)
}
}