mirror of
https://github.com/fluencelabs/wasm-bindgen
synced 2025-06-26 03:01:33 +00:00
Support long-lived closures
Docs coming soon!
This commit is contained in:
Alex Crichton
241
src/closure.rs
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241
src/closure.rs
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@ -0,0 +1,241 @@
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use std::mem::ManuallyDrop;
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use std::marker::{self, Unsize};
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use {throw, JsValue};
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use convert::*;
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use __rt::WasmRefCell;
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pub unsafe trait WasmShim<'a> {
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#[doc(hidden)]
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const DESCRIPTOR: Descriptor;
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#[doc(hidden)]
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type Wrapper;
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#[doc(hidden)]
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fn shim() -> u32;
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#[doc(hidden)]
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32;
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#[doc(hidden)]
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'a;
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#[doc(hidden)]
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fn data(t: &Self::Wrapper) -> [u32; 2];
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}
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union RawPtr<T: ?Sized> {
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ptr: *const T,
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data: [u32; 2]
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}
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macro_rules! doit {
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($(
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($($var:ident)*) => $arity:ident
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)*) => ($(
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// Fn with no return
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unsafe impl<'a, $($var: WasmAbi),*> WasmShim<'a> for Fn($($var),*) + 'a {
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const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
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type Wrapper = Box<Fn($($var),*) + 'a>;
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fn shim() -> u32 {
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#[allow(non_snake_case)]
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unsafe extern fn shim<$($var),*>(
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a: u32,
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b: u32,
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$($var:$var),*
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) {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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(*RawPtr::<Fn($($var),*)> { data: [a, b] }.ptr)($($var),*)
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}
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shim::<$($var),*> as u32
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'a {
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Box::new(u) as Box<Self>
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}
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fn data(t: &Self::Wrapper) -> [u32; 2] {
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unsafe {
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RawPtr::<Self> { ptr: &**t }.data
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}
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}
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}
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// Fn with a return
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unsafe impl<'a, $($var: WasmAbi,)* R: WasmAbi> WasmShim<'a> for Fn($($var),*) -> R + 'a {
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const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
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type Wrapper = Box<Fn($($var),*) -> R + 'a>;
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fn shim() -> u32 {
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#[allow(non_snake_case)]
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unsafe extern fn shim<$($var,)* R>(
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a: u32,
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b: u32,
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$($var:$var),*
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) -> R {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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(*RawPtr::<Fn($($var),*) -> R> { data: [a, b] }.ptr)($($var),*)
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}
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shim::<$($var,)* R> as u32
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'a {
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Box::new(u) as Box<Self>
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}
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fn data(t: &Self::Wrapper) -> [u32; 2] {
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unsafe {
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RawPtr::<Self> { ptr: &**t }.data
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}
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}
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}
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// FnMut with no return
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unsafe impl<'a, $($var: WasmAbi),*> WasmShim<'a> for FnMut($($var),*) + 'a {
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const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
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type Wrapper = Box<WasmRefCell<FnMut($($var),*) + 'a>>;
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fn shim() -> u32 {
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#[allow(non_snake_case)]
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unsafe extern fn shim<$($var),*>(
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a: u32,
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b: u32,
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$($var:$var),*
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) {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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let ptr: *const WasmRefCell<FnMut($($var),*)> = RawPtr {
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data: [a, b],
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}.ptr;
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let mut ptr = (*ptr).borrow_mut();
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(&mut *ptr)($($var),*)
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}
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shim::<$($var),*> as u32
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'a {
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Box::new(WasmRefCell::new(u)) as Box<_>
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}
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fn data(t: &Self::Wrapper) -> [u32; 2] {
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unsafe {
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RawPtr::<WasmRefCell<Self>> { ptr: &**t }.data
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}
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}
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}
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// FnMut with a return
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unsafe impl<'a, $($var: WasmAbi,)* R: WasmAbi> WasmShim<'a> for FnMut($($var),*) -> R + 'a {
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const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
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type Wrapper = Box<WasmRefCell<FnMut($($var),*) -> R + 'a>>;
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fn shim() -> u32 {
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#[allow(non_snake_case)]
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unsafe extern fn shim<$($var,)* R>(
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a: u32,
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b: u32,
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$($var:$var),*
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) -> R {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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let ptr: *const WasmRefCell<FnMut($($var),*) -> R> = RawPtr {
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data: [a, b],
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}.ptr;
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let mut ptr = (*ptr).borrow_mut();
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(&mut *ptr)($($var),*)
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}
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shim::<$($var,)* R> as u32
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'a {
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Box::new(WasmRefCell::new(u)) as Box<_>
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}
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fn data(t: &Self::Wrapper) -> [u32; 2] {
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unsafe {
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RawPtr::<WasmRefCell<Self>> { ptr: &**t }.data
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}
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}
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}
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)*)
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}
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doit! {
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() => __wbindgen_cb_arity0
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(A) => __wbindgen_cb_arity1
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(A B) => __wbindgen_cb_arity2
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(A B C) => __wbindgen_cb_arity3
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(A B C D) => __wbindgen_cb_arity4
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(A B C D E) => __wbindgen_cb_arity5
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(A B C D E F) => __wbindgen_cb_arity6
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(A B C D E F G) => __wbindgen_cb_arity7
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}
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pub struct Closure<'a, T: WasmShim<'a> + ?Sized + 'a> {
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_inner: T::Wrapper,
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js: ManuallyDrop<JsValue>,
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_marker: marker::PhantomData<&'a ()>,
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}
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impl<'a, T> Closure<'a, T>
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where T: WasmShim<'a> + ?Sized,
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{
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pub fn new<U>(t: U) -> Closure<'a, T>
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where U: Unsize<T> + 'a
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{
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Closure::wrap(T::wrap(t))
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}
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pub fn wrap(t: T::Wrapper) -> Closure<'a, T> {
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unsafe {
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let data = T::data(&t);
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let js = T::factory()(T::shim(), data[0], data[1]);
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Closure {
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_inner: t,
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js: ManuallyDrop::new(JsValue::from_abi(js, &mut GlobalStack::new())),
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_marker: marker::PhantomData,
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}
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}
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}
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}
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impl<'a, T> ToRefWasmBoundary for Closure<'a, T>
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where T: WasmShim<'a> + ?Sized,
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{
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type Abi = u32;
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const DESCRIPTOR: Descriptor = T::DESCRIPTOR;
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fn to_abi_ref(&self, extra: &mut Stack) -> u32 {
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self.js.to_abi_ref(extra)
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}
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}
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impl<'a, T> Drop for Closure<'a, T>
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where T: WasmShim<'a> + ?Sized,
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{
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fn drop(&mut self) {
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unsafe {
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let idx = self.js.to_abi_ref(&mut GlobalStack::new());
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super::__wbindgen_cb_drop(idx);
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}
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}
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}
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