mirror of
https://github.com/fluencelabs/wasm-bindgen
synced 2025-06-26 19:21:35 +00:00
Support closures with "rich" arguments
This commit adds support for closures with arguments like strings and such. In other words, closures passed to JS can now have the same suite of arguments as all functions that can be exported from Rust, as one might expect! At this time due to the way trait objects work closures still cannot use types with references like `&str`, but bare values like `String` or `ImportedType` should work just fine. Closes #104
This commit is contained in:
Alex Crichton
257
src/closure.rs
257
src/closure.rs
@ -4,13 +4,13 @@
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//! closures" from Rust to JS. Some more details can be found on the `Closure`
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//! type itself.
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use std::mem::{self, ManuallyDrop};
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use std::cell::UnsafeCell;
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use std::marker::Unsize;
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use std::mem::{self, ManuallyDrop};
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use {throw, JsValue};
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use JsValue;
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use convert::*;
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use describe::*;
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use __rt::WasmRefCell;
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/// A handle to both a closure in Rust as well as JS closure which will invoke
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/// the Rust closure.
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@ -63,13 +63,13 @@ use __rt::WasmRefCell;
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/// ClosureHandle(cb)
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/// }
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/// ```
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pub struct Closure<T: WasmShim + ?Sized> {
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_inner: T::Wrapper,
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js: ManuallyDrop<JsValue>,
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pub struct Closure<T: ?Sized> {
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inner: UnsafeCell<Box<T>>,
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js: UnsafeCell<ManuallyDrop<JsValue>>,
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}
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impl<T> Closure<T>
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where T: WasmShim + ?Sized,
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where T: ?Sized,
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{
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/// Creates a new instance of `Closure` from the provided Rust closure.
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///
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@ -86,21 +86,17 @@ impl<T> Closure<T>
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pub fn new<F>(t: F) -> Closure<T>
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where F: Unsize<T> + 'static
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{
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Closure::wrap(T::wrap(t))
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Closure::wrap(Box::new(t) as Box<T>)
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}
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/// A mostly internal function to wrap a boxed closure inside a `Closure`
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/// type.
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///
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/// This is the function where the JS closure is manufactured.
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pub fn wrap(t: T::Wrapper) -> Closure<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 { idx: js }),
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}
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pub fn wrap(t: Box<T>) -> Closure<T> {
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Closure {
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inner: UnsafeCell::new(t),
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js: UnsafeCell::new(ManuallyDrop::new(JsValue { idx: !0 })),
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}
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}
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@ -117,14 +113,17 @@ impl<T> Closure<T>
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/// cleanup as it can.
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pub fn forget(self) {
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unsafe {
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super::__wbindgen_cb_forget(self.js.idx);
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let idx = (*self.js.get()).idx;
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if idx != !0 {
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super::__wbindgen_cb_forget(idx);
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}
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mem::forget(self);
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}
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}
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}
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impl<T> WasmDescribe for Closure<T>
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where T: WasmShim + ?Sized,
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where T: WasmClosure + ?Sized,
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{
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fn describe() {
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inform(CLOSURE);
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@ -134,21 +133,38 @@ impl<T> WasmDescribe for Closure<T>
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// `Closure` can only be passed by reference to imports.
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impl<'a, T> IntoWasmAbi for &'a Closure<T>
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where T: WasmShim + ?Sized,
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where T: WasmClosure + ?Sized,
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{
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type Abi = u32;
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fn into_abi(self, _extra: &mut Stack) -> u32 {
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self.js.idx
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fn into_abi(self, extra: &mut Stack) -> u32 {
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unsafe {
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let fnptr = WasmClosure::into_abi(&mut **self.inner.get(), extra);
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extra.push(fnptr);
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&mut (*self.js.get()).idx as *const u32 as u32
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}
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}
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}
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fn _check() {
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fn _assert<T: IntoWasmAbi>() {}
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_assert::<&Closure<Fn()>>();
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_assert::<&Closure<Fn(String)>>();
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_assert::<&Closure<Fn() -> String>>();
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_assert::<&Closure<FnMut()>>();
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_assert::<&Closure<FnMut(String)>>();
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_assert::<&Closure<FnMut() -> String>>();
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}
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impl<T> Drop for Closure<T>
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where T: WasmShim + ?Sized,
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where T: ?Sized,
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{
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fn drop(&mut self) {
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unsafe {
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super::__wbindgen_cb_drop(self.js.idx);
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let idx = (*self.js.get()).idx;
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if idx != !0 {
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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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}
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@ -157,191 +173,76 @@ impl<T> Drop for Closure<T>
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///
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/// This trait is not stable and it's not recommended to use this in bounds or
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/// implement yourself.
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pub unsafe trait WasmShim: WasmDescribe {
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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> + 'static;
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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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pub unsafe trait WasmClosure: 'static {
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fn describe();
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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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unsafe fn into_abi(me: *mut Self, extra: &mut Stack) -> u32;
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}
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macro_rules! doit {
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($(
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($($var:ident)*) => $arity:ident
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($($var:ident)*)
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)*) => ($(
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// Fn with no return
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unsafe impl<$($var),*> WasmShim for Fn($($var),*)
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where $($var: WasmAbi + WasmDescribe,)*
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unsafe impl<$($var),*> WasmClosure for Fn($($var),*)
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where $($var: FromWasmAbi + 'static,)*
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{
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type Wrapper = Box<Fn($($var),*)>;
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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:$var),*
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) {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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(*RawPtr::<Fn($($var),*)> { data: [a, b] }.ptr)($($var),*)
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}
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shim::<$($var),*> as u32
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fn describe() {
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<&Self>::describe();
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
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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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unsafe fn into_abi(me: *mut Self, extra: &mut Stack) -> u32 {
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IntoWasmAbi::into_abi(&*me, extra)
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}
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}
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// Fn with a return
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unsafe impl<$($var,)* R> WasmShim for Fn($($var),*) -> R
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where $($var: WasmAbi + WasmDescribe,)*
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R: WasmAbi + WasmDescribe,
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// Fn with return
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unsafe impl<$($var,)* R> WasmClosure for Fn($($var),*) -> R
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where $($var: FromWasmAbi + 'static,)*
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R: IntoWasmAbi + 'static,
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{
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type Wrapper = Box<Fn($($var),*) -> R>;
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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:$var),*
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) -> R {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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(*RawPtr::<Fn($($var),*) -> R> { data: [a, b] }.ptr)($($var),*)
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}
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shim::<$($var,)* R> as u32
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fn describe() {
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<&Self>::describe();
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
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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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unsafe fn into_abi(me: *mut Self, extra: &mut Stack) -> u32 {
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IntoWasmAbi::into_abi(&*me, extra)
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}
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}
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// FnMut with no return
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unsafe impl<$($var),*> WasmShim for FnMut($($var),*)
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where $($var: WasmAbi + WasmDescribe,)*
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unsafe impl<$($var),*> WasmClosure for FnMut($($var),*)
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where $($var: FromWasmAbi + 'static,)*
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{
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type Wrapper = Box<WasmRefCell<FnMut($($var),*)>>;
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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:$var),*
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) {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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let ptr: *const WasmRefCell<FnMut($($var),*)> = RawPtr {
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data: [a, b],
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}.ptr;
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let mut ptr = (*ptr).borrow_mut();
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(&mut *ptr)($($var),*)
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}
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shim::<$($var),*> as u32
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fn describe() {
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<&mut Self>::describe();
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
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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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unsafe fn into_abi(me: *mut Self, extra: &mut Stack) -> u32 {
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IntoWasmAbi::into_abi(&mut *me, extra)
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}
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}
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// FnMut with a return
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unsafe impl<$($var,)* R> WasmShim for FnMut($($var),*) -> R
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where $($var: WasmAbi + WasmDescribe,)*
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R: WasmAbi + WasmDescribe,
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// FnMut with return
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unsafe impl<$($var,)* R> WasmClosure for FnMut($($var),*) -> R
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where $($var: FromWasmAbi + 'static,)*
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R: IntoWasmAbi + 'static,
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{
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type Wrapper = Box<WasmRefCell<FnMut($($var),*) -> R>>;
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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:$var),*
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) -> R {
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if a == 0 {
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throw("closure has been destroyed already");
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}
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let ptr: *const WasmRefCell<FnMut($($var),*) -> R> = RawPtr {
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data: [a, b],
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}.ptr;
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let mut ptr = (*ptr).borrow_mut();
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(&mut *ptr)($($var),*)
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}
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shim::<$($var,)* R> as u32
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fn describe() {
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<&Self>::describe();
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}
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fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
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super::$arity
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}
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fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
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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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unsafe fn into_abi(me: *mut Self, extra: &mut Stack) -> u32 {
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IntoWasmAbi::into_abi(&mut *me, extra)
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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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(A)
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(A B)
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(A B C)
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(A B C D)
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(A B C D E)
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(A B C D E F)
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(A B C D E F G)
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}
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