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Merge pull request #101 from rustwasm/closures

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Initial support for closures
This commit is contained in:
Alex Crichton 2018-04-09 16:36:01 -05:00 committed by GitHub
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23 changed files with 1357 additions and 84 deletions
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3
Cargo.toml
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@ -32,7 +32,10 @@ members = [
"examples/math", "examples/math",
"examples/performance", "examples/performance",
"examples/wasm-in-wasm", "examples/wasm-in-wasm",
"examples/closures",
] ]
[profile.release] [profile.release]
lto = true lto = true
opt-level = 'z'
panic = 'abort'

44
DESIGN.md
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@ -872,6 +872,7 @@ Under the hood this generates shims that do a bunch of translation, but it
suffices to say that a call in wasm to `foo` should always return suffices to say that a call in wasm to `foo` should always return
appropriately. appropriately.
## Customizing import behavior ## Customizing import behavior
The `#[wasm_bindgen]` macro supports a good amount of configuration for The `#[wasm_bindgen]` macro supports a good amount of configuration for
@ -1037,6 +1038,49 @@ possibilities!
All of these functions will call `console.log` in Rust, but each identifier All of these functions will call `console.log` in Rust, but each identifier
will have only one signature in Rust. will have only one signature in Rust.
## Closures
Closures are a particularly tricky topic in wasm-bindgen right now. They use
somewhat advanced language features to currently be implemented and *still* the
amount of functionality you can use is quite limiting.
Most of the implementation details of closures can be found in `src/convert.rs`
and `src/closure.rs`, effectively the `ToRefWasmBoundary` implementations for
closure types. Stack closures are pretty straightforward in that they pass
a function pointer and a data pointer to JS. This function pointer is accessed
via the exported `WebAssembly.Table` in JS, and the data pointer is passed along
eventually when the JS closure is invoked.
Stack closures currently only support `Fn` because there's no great location to
insert a `RefCell` for types like `FnMut`. This restriction may be lift-able
though in the future...
Long-lived closures are a bit more complicated. The general idea there is:
* First you create a `Closure`. This manufactures a JS callback and "passes it"
to Rust so Rust can store it.
* Next you later pass it as `&Closure<...>` to JS. This extracts the callback
from Rust and passes it to JS.
* Finally you eventually drop the Rust `Closure` which invalidates the JS
closure.
Creation of the initial JS function is done with a bunch of
`__wbindgen_cb_arityN` functions. These functions create a JS closure with the
given arity (number of arguments). This isn't really that scalable unfortunately
and also means that it's very difficult to support richer types one day. Unsure
how to solve this.
The `ToRefWasmBoundary` is quite straightforward for `Closure` as it just plucks
out the JS closure and passes it along. The real meat comes down to the
`WasmShim` internal trait. This is implemented for all the *unsized* closure
types to avoid running afoul with coherence. Each trait impl defines a shim
function to be invokeable from JS as well as the ability to wrap up the sized
verion (aka transition from `F: FnMut()` to `FnMut()`). Impls for `FnMut` also
embed the `RefCell` internally.
The `WasmShim` design is basically the first thing that got working today. It's
not great and will likely change in the future to hopefully be more flexible!
## Wrapping up ## Wrapping up
That's currently at least what `wasm-bindgen` has to offer! If you've got more That's currently at least what `wasm-bindgen` has to offer! If you've got more

77
README.md
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@ -24,8 +24,8 @@ Notable features of this project includes:
* Importing JS functionality in to Rust such as [DOM manipulation][dom-ex], * Importing JS functionality in to Rust such as [DOM manipulation][dom-ex],
[console logging][console-log], or [performance monitoring][perf-ex]. [console logging][console-log], or [performance monitoring][perf-ex].
* [Exporting Rust functionality][smorg-ex] to JS such as classes, functions, etc. * [Exporting Rust functionality][smorg-ex] to JS such as classes, functions, etc.
* Working with rich types like strings, numbers, classes, and objects rather * Working with rich types like strings, numbers, classes, closures, and objects
than simply `u32` and floats. rather than simply `u32` and floats.
This project is still relatively new but feedback is of course always This project is still relatively new but feedback is of course always
welcome! If you're curious about the design plus even more information about welcome! If you're curious about the design plus even more information about
@ -397,6 +397,79 @@ export class Awesome {
booted.then(main); booted.then(main);
``` ```
## Closures
The `#[wasm_bindgen]` attribute supports a limited subset of Rust closures being
passed to JS at this time. There are plans to expand this support currently but
it's not clear how to proceed unfortunately. In any case some examples of what
you can do are:
```rust
#[wasm_bindgen]
extern {
fn foo(a: &Fn()); // must be `Fn`, not `FnMut`
}
```
Here a function `foo` is imported from JS where the first argument is a *stack
closure*. You can call this function with a `&Fn()` argument and JS will receive
a JS function. When the `foo` function returns, however, the JS function will be
invalidated and any future usage of it will raise an exception.
Closures also support arguments and return values native to the wasm type
system, aka f32/u32:
```rust
#[wasm_bindgen]
extern {
fn bar(a: &Fn(u32, f32) -> f64);
}
```
At this time [types like strings aren't supported][cbstr] unfortunately.
[cbstr]: https://github.com/rustwasm/wasm-bindgen/issues/104
Sometimes the stack behavior of these closures is not desired. For example you'd
like to schedule a closure to be run on the next turn of the event loop in JS
through `setTimeout`. For this you want the imported function to return but the
JS closure still needs to be valid!
To support this use case you can also do:
```rust
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
extern {
fn baz(a: &Closure<Fn()>);
}
```
The `Closure` type is defined in the `wasm_bindgen` crate and represents a "long
lived" closure. The JS closure passed to `baz` is still valid after `baz`
returns, and the validity of the JS closure is tied to the lifetime of the
`Closure` in Rust. Once `Closure` is dropped it will deallocate its internal
memory and invalidate the corresponding JS function.
Unlike stack closures a `Closure` supports `FnMut`:
```rust
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
extern {
fn another(a: &Closure<FnMut() -> u32>);
}
```
Like stack closures, however, only wasm types like u32/f32 are supported today.
At this time you cannot [pass a JS closure to Rust][cbjs], you can only pass a
Rust closure to JS in limited circumstances.
[cbjs]: https://github.com/rustwasm/wasm-bindgen/issues/103
## Feature reference ## Feature reference
Here this section will attempt to be a reference for the various features Here this section will attempt to be a reference for the various features

112
crates/backend/src/ast.rs
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@ -81,10 +81,25 @@ pub struct Variant {
pub value: u32, pub value: u32,
} }
pub enum Type { pub struct Type {
ByRef(syn::Type), pub ty: syn::Type,
ByMutRef(syn::Type), pub kind: TypeKind,
ByValue(syn::Type), pub loc: TypeLocation,
}
#[derive(Copy, Clone)]
pub enum TypeKind {
ByRef,
ByMutRef,
ByValue,
}
#[derive(Copy, Clone)]
pub enum TypeLocation {
ImportArgument,
ImportRet,
ExportArgument,
ExportRet,
} }
impl Program { impl Program {
@ -197,6 +212,7 @@ impl Program {
opts, opts,
method.vis, method.vis,
true, true,
false,
); );
self.exports.push(Export { self.exports.push(Export {
class: Some(class), class: Some(class),
@ -284,7 +300,15 @@ impl Program {
pub fn push_foreign_fn(&mut self, f: syn::ForeignItemFn, opts: BindgenAttrs) -> ImportKind { pub fn push_foreign_fn(&mut self, f: syn::ForeignItemFn, opts: BindgenAttrs) -> ImportKind {
let js_name = opts.js_name().unwrap_or(f.ident); let js_name = opts.js_name().unwrap_or(f.ident);
let mut wasm = Function::from_decl(js_name, f.decl, f.attrs, opts, f.vis, false).0; let mut wasm = Function::from_decl(
js_name,
f.decl,
f.attrs,
opts,
f.vis,
false,
true,
).0;
if wasm.opts.catch() { if wasm.opts.catch() {
// TODO: this assumes a whole bunch: // TODO: this assumes a whole bunch:
// //
@ -301,11 +325,7 @@ impl Program {
let class = wasm.arguments let class = wasm.arguments
.get(0) .get(0)
.expect("methods must have at least one argument"); .expect("methods must have at least one argument");
let class = match *class { let class_name = match class.ty {
Type::ByRef(ref t) | Type::ByValue(ref t) => t,
Type::ByMutRef(_) => panic!("first method argument cannot be mutable ref"),
};
let class_name = match *class {
syn::Type::Path(syn::TypePath { syn::Type::Path(syn::TypePath {
qself: None, qself: None,
ref path, ref path,
@ -317,11 +337,11 @@ impl Program {
ImportFunctionKind::Method { ImportFunctionKind::Method {
class: class_name.as_ref().to_string(), class: class_name.as_ref().to_string(),
ty: class.clone(), ty: class.ty.clone(),
} }
} else if wasm.opts.constructor() { } else if wasm.opts.constructor() {
let class = match wasm.ret { let class = match wasm.ret {
Some(Type::ByValue(ref t)) => t, Some(Type { ref ty, kind: TypeKind::ByValue, .. }) => ty,
_ => panic!("constructor returns must be bare types"), _ => panic!("constructor returns must be bare types"),
}; };
let class_name = match *class { let class_name = match *class {
@ -416,7 +436,15 @@ impl Function {
panic!("can only bindgen safe functions"); panic!("can only bindgen safe functions");
} }
Function::from_decl(input.ident, input.decl, input.attrs, opts, input.vis, false).0 Function::from_decl(
input.ident,
input.decl,
input.attrs,
opts,
input.vis,
false,
false,
).0
} }
pub fn from_decl( pub fn from_decl(
@ -426,6 +454,7 @@ impl Function {
opts: BindgenAttrs, opts: BindgenAttrs,
vis: syn::Visibility, vis: syn::Visibility,
allow_self: bool, allow_self: bool,
import: bool,
) -> (Function, Option<bool>) { ) -> (Function, Option<bool>) {
if decl.variadic.is_some() { if decl.variadic.is_some() {
panic!("can't bindgen variadic functions") panic!("can't bindgen variadic functions")
@ -449,12 +478,24 @@ impl Function {
} }
_ => panic!("arguments cannot be `self` or ignored"), _ => panic!("arguments cannot be `self` or ignored"),
}) })
.map(|arg| Type::from(&arg.ty)) .map(|arg| {
Type::from(&arg.ty, if import {
TypeLocation::ImportArgument
} else {
TypeLocation::ExportArgument
})
})
.collect::<Vec<_>>(); .collect::<Vec<_>>();
let ret = match decl.output { let ret = match decl.output {
syn::ReturnType::Default => None, syn::ReturnType::Default => None,
syn::ReturnType::Type(_, ref t) => Some(Type::from(t)), syn::ReturnType::Type(_, ref t) => {
Some(Type::from(t, if import {
TypeLocation::ImportRet
} else {
TypeLocation::ExportRet
}))
}
}; };
( (
@ -486,19 +527,6 @@ pub fn extract_path_ident(path: &syn::Path) -> Option<syn::Ident> {
path.segments.first().map(|v| v.value().ident) path.segments.first().map(|v| v.value().ident)
} }
impl Type {
pub fn from(ty: &syn::Type) -> Type {
if let syn::Type::Reference(ref r) = *ty {
return if r.mutability.is_some() {
Type::ByMutRef((*r.elem).clone())
} else {
Type::ByRef((*r.elem).clone())
}
}
Type::ByValue(ty.clone())
}
}
impl Export { impl Export {
pub fn rust_symbol(&self) -> syn::Ident { pub fn rust_symbol(&self) -> syn::Ident {
let mut generated_name = format!("__wasm_bindgen_generated"); let mut generated_name = format!("__wasm_bindgen_generated");
@ -540,6 +568,22 @@ impl Struct {
} }
} }
impl Type {
pub fn from(ty: &syn::Type, loc: TypeLocation) -> Type {
let (ty, kind) = match *ty {
syn::Type::Reference(ref r) => {
if r.mutability.is_some() {
((*r.elem).clone(), TypeKind::ByMutRef)
} else {
((*r.elem).clone(), TypeKind::ByRef)
}
}
_ => (ty.clone(), TypeKind::ByValue),
};
Type { loc, ty, kind }
}
}
#[derive(Default)] #[derive(Default)]
pub struct BindgenAttrs { pub struct BindgenAttrs {
attrs: Vec<BindgenAttr>, attrs: Vec<BindgenAttr>,
@ -719,12 +763,12 @@ impl syn::synom::Synom for BindgenAttr {
} }
fn extract_first_ty_param(ty: Option<&Type>) -> Option<Option<Type>> { fn extract_first_ty_param(ty: Option<&Type>) -> Option<Option<Type>> {
let ty = match ty { let t = match ty {
Some(t) => t, Some(t) => t,
None => return Some(None), None => return Some(None),
}; };
let ty = match *ty { let ty = match *t {
Type::ByValue(ref t) => t, Type { ref ty, kind: TypeKind::ByValue, .. } => ty,
_ => return None, _ => return None,
}; };
let path = match *ty { let path = match *ty {
@ -747,7 +791,11 @@ fn extract_first_ty_param(ty: Option<&Type>) -> Option<Option<Type>> {
syn::Type::Tuple(ref t) if t.elems.len() == 0 => return Some(None), syn::Type::Tuple(ref t) if t.elems.len() == 0 => return Some(None),
_ => {} _ => {}
} }
Some(Some(Type::from(ty))) Some(Some(Type {
ty: ty.clone(),
kind: TypeKind::ByValue,
loc: t.loc,
}))
} }
fn term<'a>(cursor: syn::buffer::Cursor<'a>, name: &str) -> syn::synom::PResult<'a, ()> { fn term<'a>(cursor: syn::buffer::Cursor<'a>, name: &str) -> syn::synom::PResult<'a, ()> {

48
crates/backend/src/codegen.rs
View File

@ -210,8 +210,9 @@ impl ToTokens for ast::Export {
for (i, ty) in self.function.arguments.iter().enumerate() { for (i, ty) in self.function.arguments.iter().enumerate() {
let i = i + offset; let i = i + offset;
let ident = syn::Ident::from(format!("arg{}", i)); let ident = syn::Ident::from(format!("arg{}", i));
match *ty { let t = &ty.ty;
ast::Type::ByValue(ref t) => { match ty.kind {
ast::TypeKind::ByValue => {
args.push(quote! { args.push(quote! {
#ident: <#t as ::wasm_bindgen::convert::WasmBoundary>::Abi #ident: <#t as ::wasm_bindgen::convert::WasmBoundary>::Abi
}); });
@ -222,25 +223,25 @@ impl ToTokens for ast::Export {
}; };
}); });
} }
ast::Type::ByRef(ref ty) => { ast::TypeKind::ByRef => {
args.push(quote! { args.push(quote! {
#ident: <#ty as ::wasm_bindgen::convert::FromRefWasmBoundary>::Abi #ident: <#t as ::wasm_bindgen::convert::FromRefWasmBoundary>::Abi
}); });
arg_conversions.push(quote! { arg_conversions.push(quote! {
let #ident = unsafe { let #ident = unsafe {
<#ty as ::wasm_bindgen::convert::FromRefWasmBoundary> <#t as ::wasm_bindgen::convert::FromRefWasmBoundary>
::from_abi_ref(#ident, &mut __stack) ::from_abi_ref(#ident, &mut __stack)
}; };
let #ident = &*#ident; let #ident = &*#ident;
}); });
} }
ast::Type::ByMutRef(ref ty) => { ast::TypeKind::ByMutRef => {
args.push(quote! { args.push(quote! {
#ident: <#ty as ::wasm_bindgen::convert::FromRefMutWasmBoundary>::Abi #ident: <#t as ::wasm_bindgen::convert::FromRefMutWasmBoundary>::Abi
}); });
arg_conversions.push(quote! { arg_conversions.push(quote! {
let mut #ident = unsafe { let mut #ident = unsafe {
<#ty as ::wasm_bindgen::convert::FromRefMutWasmBoundary> <#t as ::wasm_bindgen::convert::FromRefMutWasmBoundary>
::from_abi_ref_mut(#ident, &mut __stack) ::from_abi_ref_mut(#ident, &mut __stack)
}; };
let #ident = &mut *#ident; let #ident = &mut *#ident;
@ -252,19 +253,19 @@ impl ToTokens for ast::Export {
let ret_ty; let ret_ty;
let convert_ret; let convert_ret;
match self.function.ret { match self.function.ret {
Some(ast::Type::ByValue(ref t)) => { Some(ast::Type { ref ty, kind: ast::TypeKind::ByValue, .. }) => {
ret_ty = quote! { ret_ty = quote! {
-> <#t as ::wasm_bindgen::convert::WasmBoundary>::Abi -> <#ty as ::wasm_bindgen::convert::WasmBoundary>::Abi
}; };
convert_ret = quote! { convert_ret = quote! {
<#t as ::wasm_bindgen::convert::WasmBoundary> <#ty as ::wasm_bindgen::convert::WasmBoundary>
::into_abi(#ret, &mut unsafe { ::into_abi(#ret, &mut unsafe {
::wasm_bindgen::convert::GlobalStack::new() ::wasm_bindgen::convert::GlobalStack::new()
}) })
}; };
} }
Some(ast::Type::ByMutRef(_)) Some(ast::Type { kind: ast::TypeKind::ByMutRef, .. }) |
| Some(ast::Type::ByRef(_)) => { Some(ast::Type { kind: ast::TypeKind::ByRef, .. }) => {
panic!("can't return a borrowed ref"); panic!("can't return a borrowed ref");
} }
None => { None => {
@ -432,8 +433,9 @@ impl ToTokens for ast::ImportFunction {
}); });
for (i, (ty, name)) in self.function.arguments.iter().zip(names).enumerate() { for (i, (ty, name)) in self.function.arguments.iter().zip(names).enumerate() {
match *ty { let t = &ty.ty;
ast::Type::ByValue(ref t) => { match ty.kind {
ast::TypeKind::ByValue => {
abi_argument_names.push(name); abi_argument_names.push(name);
abi_arguments.push(quote! { abi_arguments.push(quote! {
#name: <#t as ::wasm_bindgen::convert::WasmBoundary>::Abi #name: <#t as ::wasm_bindgen::convert::WasmBoundary>::Abi
@ -448,8 +450,8 @@ impl ToTokens for ast::ImportFunction {
::into_abi(#var, &mut __stack); ::into_abi(#var, &mut __stack);
}); });
} }
ast::Type::ByMutRef(_) => panic!("urgh mut"), ast::TypeKind::ByMutRef => panic!("urgh mut"),
ast::Type::ByRef(ref t) => { ast::TypeKind::ByRef => {
abi_argument_names.push(name); abi_argument_names.push(name);
abi_arguments.push(quote! { #name: u32 }); abi_arguments.push(quote! { #name: u32 });
let var = if i == 0 && is_method { let var = if i == 0 && is_method {
@ -467,20 +469,22 @@ impl ToTokens for ast::ImportFunction {
let abi_ret; let abi_ret;
let mut convert_ret; let mut convert_ret;
match self.function.ret { match self.function.ret {
Some(ast::Type::ByValue(ref t)) => { Some(ast::Type { ref ty, kind: ast::TypeKind::ByValue, .. }) => {
abi_ret = quote! { abi_ret = quote! {
<#t as ::wasm_bindgen::convert::WasmBoundary>::Abi <#ty as ::wasm_bindgen::convert::WasmBoundary>::Abi
}; };
convert_ret = quote! { convert_ret = quote! {
<#t as ::wasm_bindgen::convert::WasmBoundary> <#ty as ::wasm_bindgen::convert::WasmBoundary>
::from_abi( ::from_abi(
#ret_ident, #ret_ident,
&mut ::wasm_bindgen::convert::GlobalStack::new(), &mut ::wasm_bindgen::convert::GlobalStack::new(),
) )
}; };
} }
Some(ast::Type::ByRef(_)) Some(ast::Type { kind: ast::TypeKind::ByRef, .. }) |
| Some(ast::Type::ByMutRef(_)) => panic!("can't return a borrowed ref"), Some(ast::Type { kind: ast::TypeKind::ByMutRef, .. }) => {
panic!("can't return a borrowed ref")
}
None => { None => {
abi_ret = quote! { () }; abi_ret = quote! { () };
convert_ret = quote! { () }; convert_ret = quote! { () };

25
crates/backend/src/literal.rs
View File

@ -139,19 +139,32 @@ impl Literal for ast::Function {
impl Literal for ast::Type { impl Literal for ast::Type {
fn literal(&self, a: &mut LiteralBuilder) { fn literal(&self, a: &mut LiteralBuilder) {
match *self { let t = &self.ty;
ast::Type::ByValue(ref t) => { match self.kind {
ast::TypeKind::ByValue => {
a.as_char(quote! { a.as_char(quote! {
<#t as ::wasm_bindgen::convert::WasmBoundary>::DESCRIPTOR <#t as ::wasm_bindgen::convert::WasmBoundary>::DESCRIPTOR
}); });
} }
ast::Type::ByRef(ref ty) | ast::Type::ByMutRef(ref ty) => { ast::TypeKind::ByRef |
// TODO: this assumes `ToRef*` and `FromRef*` use the same ast::TypeKind::ByMutRef => {
// descriptor. match self.loc {
ast::TypeLocation::ImportArgument |
ast::TypeLocation::ExportRet => {
a.as_char(quote! { a.as_char(quote! {
<#ty as ::wasm_bindgen::convert::FromRefWasmBoundary>::DESCRIPTOR <#t as ::wasm_bindgen::convert::ToRefWasmBoundary>
::DESCRIPTOR
}); });
} }
ast::TypeLocation::ImportRet |
ast::TypeLocation::ExportArgument => {
a.as_char(quote! {
<#t as ::wasm_bindgen::convert::FromRefWasmBoundary>
::DESCRIPTOR
});
}
}
}
} }
} }
} }

121
crates/cli-support/src/js.rs
View File

@ -2,8 +2,10 @@ use std::collections::{HashSet, HashMap};
use std::fmt::Write; use std::fmt::Write;
use std::mem; use std::mem;
use shared;
use parity_wasm::elements::*; use parity_wasm::elements::*;
use parity_wasm;
use shared;
use wasm_gc;
use super::Bindgen; use super::Bindgen;
@ -19,6 +21,7 @@ pub struct Context<'a> {
pub custom_type_names: HashMap<u32, String>, pub custom_type_names: HashMap<u32, String>,
pub imported_names: HashSet<String>, pub imported_names: HashSet<String>,
pub exported_classes: HashMap<String, ExportedClass>, pub exported_classes: HashMap<String, ExportedClass>,
pub function_table_needed: bool,
} }
#[derive(Default)] #[derive(Default)]
@ -60,6 +63,8 @@ impl<'a> Context<'a> {
} }
pub fn finalize(&mut self, module_name: &str) -> (String, String) { pub fn finalize(&mut self, module_name: &str) -> (String, String) {
self.unexport_unused_internal_exports();
self.gc();
self.write_classes(); self.write_classes();
{ {
let mut bind = |name: &str, f: &Fn(&mut Self) -> String| { let mut bind = |name: &str, f: &Fn(&mut Self) -> String| {
@ -219,6 +224,43 @@ impl<'a> Context<'a> {
return ptr; return ptr;
}") }")
}); });
for i in 0..8 {
let name = format!("__wbindgen_cb_arity{}", i);
bind(&name, &|me| {
me.expose_add_heap_object();
me.function_table_needed = true;
let args = (0..i)
.map(|x| format!("arg{}", x))
.collect::<Vec<_>>()
.join(", ");
format!("function(a, b, c) {{
const cb = function({0}) {{
return this.f(this.a, this.b {1} {0});
}};
cb.a = b;
cb.b = c;
cb.f = wasm.__wbg_function_table.get(a);
let real = cb.bind(cb);
real.original = cb;
return addHeapObject(real);
}}", args, if i == 0 {""} else {","})
});
}
bind("__wbindgen_cb_drop", &|me| {
me.expose_drop_ref();
String::from("function(i) {
let obj = getObject(i).original;
obj.a = obj.b = 0;
dropRef(i);
}")
});
bind("__wbindgen_cb_forget", &|me| {
me.expose_drop_ref();
String::from("function(i) {
dropRef(i);
}")
});
} }
self.rewrite_imports(module_name); self.rewrite_imports(module_name);
@ -245,7 +287,8 @@ impl<'a> Context<'a> {
footer = self.footer, footer = self.footer,
); );
self.unexport_unused_internal_exports(); self.export_table();
self.gc();
(js, self.typescript.clone()) (js, self.typescript.clone())
} }
@ -270,6 +313,7 @@ impl<'a> Context<'a> {
let new_name = shared::new_function(&class); let new_name = shared::new_function(&class);
if self.wasm_import_needed(&new_name) { if self.wasm_import_needed(&new_name) {
self.expose_add_heap_object();
self.export(&new_name, &format!(" self.export(&new_name, &format!("
function(ptr) {{ function(ptr) {{
return addHeapObject(new {class}(ptr, token)); return addHeapObject(new {class}(ptr, token));
@ -286,6 +330,7 @@ impl<'a> Context<'a> {
let new_name = shared::new_function(&class); let new_name = shared::new_function(&class);
if self.wasm_import_needed(&new_name) { if self.wasm_import_needed(&new_name) {
self.expose_add_heap_object();
self.export(&new_name, &format!(" self.export(&new_name, &format!("
function(ptr) {{ function(ptr) {{
return addHeapObject(new {class}(ptr)); return addHeapObject(new {class}(ptr));
@ -313,6 +358,22 @@ impl<'a> Context<'a> {
} }
} }
fn export_table(&mut self) {
if !self.function_table_needed {
return
}
for section in self.module.sections_mut() {
let exports = match *section {
Section::Export(ref mut s) => s,
_ => continue,
};
let entry = ExportEntry::new("__wbg_function_table".to_string(),
Internal::Table(0));
exports.entries_mut().push(entry);
break
}
}
fn rewrite_imports(&mut self, module_name: &str) { fn rewrite_imports(&mut self, module_name: &str) {
for (name, contents) in self._rewrite_imports(module_name) { for (name, contents) in self._rewrite_imports(module_name) {
self.export(&name, &contents); self.export(&name, &contents);
@ -1105,6 +1166,16 @@ impl<'a> Context<'a> {
} }
"); ");
} }
fn gc(&mut self) {
let module = mem::replace(self.module, Module::default());
let wasm_bytes = parity_wasm::serialize(module).unwrap();
let bytes = wasm_gc::Config::new()
.demangle(false)
.gc(&wasm_bytes)
.unwrap();
*self.module = deserialize_buffer(&bytes).unwrap();
}
} }
impl<'a, 'b> SubContext<'a, 'b> { impl<'a, 'b> SubContext<'a, 'b> {
@ -1404,6 +1475,7 @@ impl<'a, 'b> SubContext<'a, 'b> {
let mut abi_args = Vec::new(); let mut abi_args = Vec::new();
let mut extra = String::new(); let mut extra = String::new();
let mut finally = String::new();
let mut next_global = 0; let mut next_global = 0;
for (i, arg) in import.function.arguments.iter().enumerate() { for (i, arg) in import.function.arguments.iter().enumerate() {
@ -1419,6 +1491,40 @@ impl<'a, 'b> SubContext<'a, 'b> {
self.cx.expose_get_object(); self.cx.expose_get_object();
format!("getObject(arg{})", i) format!("getObject(arg{})", i)
} }
shared::TYPE_FUNC => {
self.cx.expose_get_object();
format!("getObject(arg{})", i)
}
shared::TYPE_STACK_FUNC0 |
shared::TYPE_STACK_FUNC1 |
shared::TYPE_STACK_FUNC2 |
shared::TYPE_STACK_FUNC3 |
shared::TYPE_STACK_FUNC4 |
shared::TYPE_STACK_FUNC5 |
shared::TYPE_STACK_FUNC6 |
shared::TYPE_STACK_FUNC7 => {
let nargs = *arg - shared::TYPE_STACK_FUNC0;
let args = (0..nargs)
.map(|i| format!("arg{}", i))
.collect::<Vec<_>>()
.join(", ");
self.cx.expose_get_global_argument();
self.cx.function_table_needed = true;
let sep = if nargs == 0 {""} else {","};
extra.push_str(&format!("
let cb{0} = function({args}) {{
return this.f(this.a, this.b {sep} {args});
}};
cb{0}.f = wasm.__wbg_function_table.get(arg{0});
cb{0}.a = getGlobalArgument({next_global});
cb{0}.b = getGlobalArgument({next_global} + 1);
", i, next_global = next_global, args = args, sep = sep));
next_global += 2;
finally.push_str(&format!("
cb{0}.a = cb{0}.b = 0;
", i));
format!("cb{0}.bind(cb{0})", i)
}
other => { other => {
match VectorType::from(other) { match VectorType::from(other) {
Some(ty) => { Some(ty) => {
@ -1585,6 +1691,17 @@ impl<'a, 'b> SubContext<'a, 'b> {
} else { } else {
invoc invoc
}; };
let invoc = if finally.len() > 0 {
format!("
try {{
{}
}} finally {{
{}
}}
", invoc, finally)
} else {
invoc
};
dst.push_str(&abi_args.join(", ")); dst.push_str(&abi_args.join(", "));
dst.push_str(") {\n"); dst.push_str(") {\n");

6
crates/cli-support/src/lib.rs
View File

@ -94,6 +94,7 @@ impl Bindgen {
exported_classes: Default::default(), exported_classes: Default::default(),
config: &self, config: &self,
module: &mut module, module: &mut module,
function_table_needed: false,
}; };
for program in programs.iter() { for program in programs.iter() {
cx.add_custom_type_names(program); cx.add_custom_type_names(program);
@ -128,10 +129,7 @@ impl Bindgen {
let wasm_bytes = parity_wasm::serialize(module).map_err(|e| { let wasm_bytes = parity_wasm::serialize(module).map_err(|e| {
Error(format!("{:?}", e)) Error(format!("{:?}", e))
})?; })?;
let bytes = wasm_gc::Config::new() File::create(&wasm_path)?.write_all(&wasm_bytes)?;
.demangle(false)
.gc(&wasm_bytes)?;
File::create(&wasm_path)?.write_all(&bytes)?;
Ok(()) Ok(())
} }

11
crates/shared/src/lib.rs
View File

@ -146,8 +146,17 @@ pub const TYPE_SLICE_F64: u32 = 20;
pub const TYPE_VECTOR_F64: u32 = 21; pub const TYPE_VECTOR_F64: u32 = 21;
pub const TYPE_JS_OWNED: u32 = 22; pub const TYPE_JS_OWNED: u32 = 22;
pub const TYPE_JS_REF: u32 = 23; pub const TYPE_JS_REF: u32 = 23;
pub const TYPE_STACK_FUNC0: u32 = 24;
pub const TYPE_STACK_FUNC1: u32 = 25;
pub const TYPE_STACK_FUNC2: u32 = 26;
pub const TYPE_STACK_FUNC3: u32 = 27;
pub const TYPE_STACK_FUNC4: u32 = 28;
pub const TYPE_STACK_FUNC5: u32 = 29;
pub const TYPE_STACK_FUNC6: u32 = 30;
pub const TYPE_STACK_FUNC7: u32 = 31;
pub const TYPE_FUNC: u32 = 32;
pub const TYPE_CUSTOM_START: u32 = 24; pub const TYPE_CUSTOM_START: u32 = 40;
pub const TYPE_CUSTOM_REF_FLAG: u32 = 1; pub const TYPE_CUSTOM_REF_FLAG: u32 = 1;
pub fn name_to_descriptor(name: &str) -> u32 { pub fn name_to_descriptor(name: &str) -> u32 {

2
examples/README.md
View File

@ -22,3 +22,5 @@ The examples here are:
operations in Rust operations in Rust
* `wasm-in-wasm` - how to interact with namespaced APIs like * `wasm-in-wasm` - how to interact with namespaced APIs like
`WebAssembly.Module` and shows off creation of a WebAssembly module from Rust `WebAssembly.Module` and shows off creation of a WebAssembly module from Rust
* `closures` - an example of how to invoke functions like `setInterval` or use
the `onclick` property in conjunction with closures.

4
examples/closures/.gitignore vendored Normal file
View File

@ -0,0 +1,4 @@
package-lock.json
closures.js
closures_bg.js
closures_bg.wasm

10
examples/closures/Cargo.toml Normal file
View File

@ -0,0 +1,10 @@
[package]
name = "closures"
version = "0.1.0"
authors = ["Alex Crichton <alex@alexcrichton.com>"]
[lib]
crate-type = ["cdylib"]
[dependencies]
wasm-bindgen = { path = "../.." }

20
examples/closures/README.md Normal file
View File

@ -0,0 +1,20 @@
# Closure examples
This directory is an example of using the `#[wasm_bindgen]` macro with closures
to interact with the DOM.
You can build the example with:
```
$ ./build.sh
```
(or running the commands on Windows manually)
and then opening up `index.html` in a web browser should show a hello message on
the web page generated by the wasm.
For more information about this example be sure to check out
[`hello_world`][hello] which also has more comments about caveats and such.
[hello]: https://github.com/alexcrichton/wasm-bindgen/tree/master/examples/hello_world

12
examples/closures/build.sh Executable file
View File

@ -0,0 +1,12 @@
#!/bin/sh
# For more coments about what's going on here, see the `hello_world` example
set -ex
cargo +nightly build --target wasm32-unknown-unknown
cargo +nightly run --manifest-path ../../crates/cli/Cargo.toml \
--bin wasm-bindgen -- \
../../target/wasm32-unknown-unknown/debug/closures.wasm --out-dir .
#npm install
npm run serve

40
examples/closures/index.html Normal file
View File

@ -0,0 +1,40 @@
<html>
<head>
<meta content="text/html;charset=utf-8" http-equiv="Content-Type"/>
<style>
#green-square {
background: green;
width: 200px;
height: 200px;
text-align: center;
line-height: 200px;
color: white;
}
#green-square span {
display: inline-block;
vertical-align: middle;
}
</style>
</head>
<body>
<div id='loading'>
Loading...
</div>
<div id='script' style='display:none'>
<p>
The current time is:
<span id='current-time'>...</span>
</p>
<div id='green-square'>
<span>Click me!</span>
</div>
<p>
You've clicked the green square
<span id='num-clicks'>0</span>
times
</p>
</div>
<script src='./index.js'></script>
</body>
</html>

4
examples/closures/index.js Normal file
View File

@ -0,0 +1,4 @@
// For more comments about what's going on here, check out the `hello_world`
// example
const rust = import("./closures");
rust.then(m => m.run());

10
examples/closures/package.json Normal file
View File

@ -0,0 +1,10 @@
{
"scripts": {
"serve": "webpack-dev-server"
},
"devDependencies": {
"webpack": "^4.0.1",
"webpack-cli": "^2.0.10",
"webpack-dev-server": "^3.1.0"
}
}

94
examples/closures/src/lib.rs Normal file
View File

@ -0,0 +1,94 @@
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
extern {
// Binding for the `setInverval` method in JS. This function takes a "long
// lived" closure as the first argument so we use `Closure` instead of
// a bare `&Fn()` which only surives for that one stack frame.
//
// The second argument is then the interval and the return value is how we
// clear this interval. We're not going to clear our interval in this
// example though so the return value is ignored.
#[wasm_bindgen(js_name = setInterval)]
fn set_interval(cb: &Closure<FnMut()>, delay: u32) -> f64;
// Bindings for JS `Date` so we can update our local timer
type Date;
#[wasm_bindgen(constructor)]
fn new() -> Date;
#[wasm_bindgen(method, js_name = toLocaleString)]
fn to_locale_string(this: &Date) -> String;
// Bindings for `document` and various methods of updating HTML elements.
// Like with the `dom` example these'll ideally be upstream in a generated
// crate one day but for now we manually define them.
type HTMLDocument;
static document: HTMLDocument;
#[wasm_bindgen(method, js_name = getElementById)]
fn get_element_by_id(this: &HTMLDocument, id: &str) -> Element;
#[wasm_bindgen(method, js_name = getElementById)]
fn get_html_element_by_id(this: &HTMLDocument, id: &str) -> HTMLElement;
type Element;
#[wasm_bindgen(method, setter = innerHTML)]
fn set_inner_html(this: &Element, html: &str);
type HTMLElement;
#[wasm_bindgen(method, setter)]
fn set_onclick(this: &HTMLElement, cb: &Closure<FnMut()>);
#[wasm_bindgen(method, getter)]
fn style(this: &HTMLElement) -> CSS2Properties;
type CSS2Properties;
#[wasm_bindgen(method, setter)]
fn set_display(this: &CSS2Properties, display: &str);
}
#[wasm_bindgen]
pub fn run() {
// Set up a clock on our page and update it each second to ensure it's got
// an accurate date.
let a = Closure::new(update_time);
set_interval(&a, 1000);
update_time();
fn update_time() {
document.get_element_by_id("current-time")
.set_inner_html(&Date::new().to_locale_string());
}
// We also want to count the number of times that our green square has been
// clicked. Our callback will update the `#num-clicks` div
let square = document.get_html_element_by_id("green-square");
let mut clicks = 0;
let b = Closure::new(move || {
clicks += 1;
document.get_element_by_id("num-clicks")
.set_inner_html(&clicks.to_string());
});
square.set_onclick(&b);
// The instances of `Closure` that we created will invalidate their
// corresponding JS callback whenever they're dropped, so if we were to
// normally return from `run` then both of our registered closures will
// raise exceptions when invoked.
//
// Normally we'd store these handles to later get dropped at an appropriate
// time but for now we want these to be global handlers so we use the
// `forget` method to drop them without invalidating the closure. Note that
// this is leaking memory in Rust, so this should be done judiciously!
a.forget();
b.forget();
// And finally now that our demo is ready to go let's switch things up so
// everything is displayed and our loading prompt is hidden.
document.get_html_element_by_id("loading")
.style()
.set_display("none");
document.get_html_element_by_id("script")
.style()
.set_display("block");
}

10
examples/closures/webpack.config.js Normal file
View File

@ -0,0 +1,10 @@
const path = require('path');
module.exports = {
entry: "./index.js",
output: {
path: path.resolve(__dirname, "dist"),
filename: "index.js",
},
mode: "development"
};

335
src/closure.rs Normal file
View File

@ -0,0 +1,335 @@
//! Support for long-lived closures in `wasm-bindgen`
//!
//! This module defines the `Closure` type which is used to pass "owned
//! closures" from Rust to JS. Some more details can be found on the `Closure`
//! type itself.
use std::mem::{self, ManuallyDrop};
use std::marker::Unsize;
use {throw, JsValue};
use convert::*;
use __rt::WasmRefCell;
/// A handle to both a closure in Rust as well as JS closure which will invoke
/// the Rust closure.
///
/// A `Closure` is the primary way that a `'static` lifetime closure is
/// transferred from Rust to JS. `Closure` currently requires that the closures
/// it's created with have the `'static` lifetime in Rust for soundness reasons.
///
/// This type is a "handle" in the sense that whenever it is dropped it will
/// invalidate the JS closure that it refers to. Any usage of the closure in JS
/// after the `Closure` has been dropped will raise an exception. It's then up
/// to you to arrange for `Closure` to be properly deallocate at an appropriate
/// location in your program.
///
/// The type parameter on `Closure` is the type of closure that this represents.
/// Currently this can only be the `Fn` and `FnMut` traits with up to 7
/// arguments (and an optional return value). The arguments/return value of the
/// trait must be numbers like `u32` for now, although this restriction may be
/// lifted in the future!
///
/// # Example
///
/// ```rust,no_run
/// #[wasm_bindgen]
/// extern {
/// fn setTimeout(closure: &Closure<FnMut()>, time: u32);
///
/// #[wasm_bindgen(js_namespace = console)]
/// fn log(s: &str);
/// }
///
/// #[wasm_bindgen]
/// pub struct ClosureHandle(Closure<FnMut()>);
///
/// #[wasm_bindgen]
/// pub fn run() -> ClosureHandle {
/// // First up we use `Closure::new` to wrap up a Rust closure and create
/// a JS closure.
/// let cb = Closure::new(|| {
/// log("timeout elapsed!");
/// });
///
/// // Next we pass this via reference to the `setTimeout` function, and
/// // `setTimeout` gets a handle to the corresponding JS closure.
/// setTimeout(&cb, 1_000);
///
/// // If we were to drop `cb` here it would cause an exception to be raised
/// // when the timeout elapses. Instead we *return* our handle back to JS
/// // so JS can tell us later when it would like to deallocate this handle.
/// ClosureHandle(cb)
/// }
/// ```
pub struct Closure<T: WasmShim + ?Sized> {
_inner: T::Wrapper,
js: ManuallyDrop<JsValue>,
}
impl<T> Closure<T>
where T: WasmShim + ?Sized,
{
/// Creates a new instance of `Closure` from the provided Rust closure.
///
/// Note that the closure provided here, `F`, has a few requirements
/// associated with it:
///
/// * It must implement `Fn` or `FnMut`
/// * It must be `'static`, aka no stack references (use the `move` keyword)
/// * It can have at most 7 arguments
/// * Its arguments and return values are all wasm types like u32/f64.
///
/// This is unfortunately pretty restrictive for now but hopefully some of
/// these restrictions can be lifted in the future!
pub fn new<F>(t: F) -> Closure<T>
where F: Unsize<T> + 'static
{
Closure::wrap(T::wrap(t))
}
/// A mostly internal function to wrap a boxed closure inside a `Closure`
/// type.
///
/// This is the function where the JS closure is manufactured.
pub fn wrap(t: T::Wrapper) -> Closure<T> {
unsafe {
let data = T::data(&t);
let js = T::factory()(T::shim(), data[0], data[1]);
Closure {
_inner: t,
js: ManuallyDrop::new(JsValue::from_abi(js, &mut GlobalStack::new())),
}
}
}
/// Leaks this `Closure` to ensure it remains valid for the duration of the
/// entire program.
///
/// > **Note**: this function will leak memory. It should be used sparingly
/// > to ensure the memory leak doesn't affect the program too much.
///
/// When a `Closure` is dropped it will invalidate the associated JS
/// closure, but this isn't always desired. Some callbacks are alive for
/// the entire duration of the program, so this can be used to conveniently
/// leak this instance of `Closure` while performing as much internal
/// cleanup as it can.
pub fn forget(self) {
unsafe {
super::__wbindgen_cb_forget(self.js.to_abi_ref(&mut GlobalStack::new()));
mem::forget(self);
}
}
}
// `Closure` can only be passed by reference to imports.
impl<T> ToRefWasmBoundary for Closure<T>
where T: WasmShim + ?Sized,
{
type Abi = u32;
const DESCRIPTOR: Descriptor = T::DESCRIPTOR;
fn to_abi_ref(&self, extra: &mut Stack) -> u32 {
self.js.to_abi_ref(extra)
}
}
impl<T> Drop for Closure<T>
where T: WasmShim + ?Sized,
{
fn drop(&mut self) {
unsafe {
let idx = self.js.to_abi_ref(&mut GlobalStack::new());
super::__wbindgen_cb_drop(idx);
}
}
}
/// An internal trait for the `Closure` type.
///
/// This trait is not stable and it's not recommended to use this in bounds or
/// implement yourself.
pub unsafe trait WasmShim {
#[doc(hidden)]
const DESCRIPTOR: Descriptor;
#[doc(hidden)]
type Wrapper;
#[doc(hidden)]
fn shim() -> u32;
#[doc(hidden)]
fn factory() -> unsafe extern fn(u32, u32, u32) -> u32;
#[doc(hidden)]
fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static;
#[doc(hidden)]
fn data(t: &Self::Wrapper) -> [u32; 2];
}
union RawPtr<T: ?Sized> {
ptr: *const T,
data: [u32; 2]
}
macro_rules! doit {
($(
($($var:ident)*) => $arity:ident
)*) => ($(
// Fn with no return
unsafe impl<$($var: WasmAbi),*> WasmShim for Fn($($var),*) {
const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
type Wrapper = Box<Fn($($var),*)>;
fn shim() -> u32 {
#[allow(non_snake_case)]
unsafe extern fn shim<$($var),*>(
a: u32,
b: u32,
$($var:$var),*
) {
if a == 0 {
throw("closure has been destroyed already");
}
(*RawPtr::<Fn($($var),*)> { data: [a, b] }.ptr)($($var),*)
}
shim::<$($var),*> as u32
}
fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
super::$arity
}
fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
Box::new(u) as Box<Self>
}
fn data(t: &Self::Wrapper) -> [u32; 2] {
unsafe {
RawPtr::<Self> { ptr: &**t }.data
}
}
}
// Fn with a return
unsafe impl<$($var: WasmAbi,)* R: WasmAbi> WasmShim for Fn($($var),*) -> R {
const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
type Wrapper = Box<Fn($($var),*) -> R>;
fn shim() -> u32 {
#[allow(non_snake_case)]
unsafe extern fn shim<$($var,)* R>(
a: u32,
b: u32,
$($var:$var),*
) -> R {
if a == 0 {
throw("closure has been destroyed already");
}
(*RawPtr::<Fn($($var),*) -> R> { data: [a, b] }.ptr)($($var),*)
}
shim::<$($var,)* R> as u32
}
fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
super::$arity
}
fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
Box::new(u) as Box<Self>
}
fn data(t: &Self::Wrapper) -> [u32; 2] {
unsafe {
RawPtr::<Self> { ptr: &**t }.data
}
}
}
// FnMut with no return
unsafe impl<$($var: WasmAbi),*> WasmShim for FnMut($($var),*) {
const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
type Wrapper = Box<WasmRefCell<FnMut($($var),*)>>;
fn shim() -> u32 {
#[allow(non_snake_case)]
unsafe extern fn shim<$($var),*>(
a: u32,
b: u32,
$($var:$var),*
) {
if a == 0 {
throw("closure has been destroyed already");
}
let ptr: *const WasmRefCell<FnMut($($var),*)> = RawPtr {
data: [a, b],
}.ptr;
let mut ptr = (*ptr).borrow_mut();
(&mut *ptr)($($var),*)
}
shim::<$($var),*> as u32
}
fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
super::$arity
}
fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
Box::new(WasmRefCell::new(u)) as Box<_>
}
fn data(t: &Self::Wrapper) -> [u32; 2] {
unsafe {
RawPtr::<WasmRefCell<Self>> { ptr: &**t }.data
}
}
}
// FnMut with a return
unsafe impl<$($var: WasmAbi,)* R: WasmAbi> WasmShim for FnMut($($var),*) -> R {
const DESCRIPTOR: Descriptor = DESCRIPTOR_FUNC;
type Wrapper = Box<WasmRefCell<FnMut($($var),*) -> R>>;
fn shim() -> u32 {
#[allow(non_snake_case)]
unsafe extern fn shim<$($var,)* R>(
a: u32,
b: u32,
$($var:$var),*
) -> R {
if a == 0 {
throw("closure has been destroyed already");
}
let ptr: *const WasmRefCell<FnMut($($var),*) -> R> = RawPtr {
data: [a, b],
}.ptr;
let mut ptr = (*ptr).borrow_mut();
(&mut *ptr)($($var),*)
}
shim::<$($var,)* R> as u32
}
fn factory() -> unsafe extern fn(u32, u32, u32) -> u32 {
super::$arity
}
fn wrap<U>(u: U) -> Self::Wrapper where U: Unsize<Self> + 'static {
Box::new(WasmRefCell::new(u)) as Box<_>
}
fn data(t: &Self::Wrapper) -> [u32; 2] {
unsafe {
RawPtr::<WasmRefCell<Self>> { ptr: &**t }.data
}
}
}
)*)
}
doit! {
() => __wbindgen_cb_arity0
(A) => __wbindgen_cb_arity1
(A B) => __wbindgen_cb_arity2
(A B C) => __wbindgen_cb_arity3
(A B C D) => __wbindgen_cb_arity4
(A B C D E) => __wbindgen_cb_arity5
(A B C D E F) => __wbindgen_cb_arity6
(A B C D E F G) => __wbindgen_cb_arity7
}

87
src/convert.rs
View File

@ -3,7 +3,7 @@ use std::ops::{Deref, DerefMut};
use std::slice; use std::slice;
use std::str; use std::str;
use super::JsValue; use {JsValue, throw};
#[derive(PartialEq, Eq, Copy, Clone)] #[derive(PartialEq, Eq, Copy, Clone)]
pub struct Descriptor { pub struct Descriptor {
@ -21,6 +21,17 @@ pub const DESCRIPTOR_BOOLEAN: Descriptor = Descriptor { __x: *b" 5", };
pub const DESCRIPTOR_JS_OWNED: Descriptor = Descriptor { __x: *b" 22", }; pub const DESCRIPTOR_JS_OWNED: Descriptor = Descriptor { __x: *b" 22", };
pub const DESCRIPTOR_JS_REF: Descriptor = Descriptor { __x: *b" 23", }; pub const DESCRIPTOR_JS_REF: Descriptor = Descriptor { __x: *b" 23", };
pub const DESCRIPTOR_STACK_FUNC0: Descriptor = Descriptor { __x: *b" 24", };
pub const DESCRIPTOR_STACK_FUNC1: Descriptor = Descriptor { __x: *b" 25", };
pub const DESCRIPTOR_STACK_FUNC2: Descriptor = Descriptor { __x: *b" 26", };
pub const DESCRIPTOR_STACK_FUNC3: Descriptor = Descriptor { __x: *b" 27", };
pub const DESCRIPTOR_STACK_FUNC4: Descriptor = Descriptor { __x: *b" 28", };
pub const DESCRIPTOR_STACK_FUNC5: Descriptor = Descriptor { __x: *b" 29", };
pub const DESCRIPTOR_STACK_FUNC6: Descriptor = Descriptor { __x: *b" 30", };
pub const DESCRIPTOR_STACK_FUNC7: Descriptor = Descriptor { __x: *b" 31", };
pub const DESCRIPTOR_FUNC: Descriptor = Descriptor { __x: *b" 32", };
pub trait WasmBoundary { pub trait WasmBoundary {
type Abi: WasmAbi; type Abi: WasmAbi;
const DESCRIPTOR: Descriptor; const DESCRIPTOR: Descriptor;
@ -337,3 +348,77 @@ impl Stack for GlobalStack {
pub unsafe extern fn __wbindgen_global_argument_ptr() -> *mut u32 { pub unsafe extern fn __wbindgen_global_argument_ptr() -> *mut u32 {
GLOBAL_STACK.as_mut_ptr() GLOBAL_STACK.as_mut_ptr()
} }
macro_rules! stack_closures {
($(
($($var:ident)*) => $descriptor:ident
)*) => ($(
impl<'a, $($var,)* R> ToRefWasmBoundary for Fn($($var),*) -> R + 'a
where $($var: WasmAbi,)*
R: WasmAbi
{
type Abi = u32;
const DESCRIPTOR: Descriptor = $descriptor;
fn to_abi_ref(&self, extra: &mut Stack) -> u32 {
#[allow(non_snake_case)]
unsafe extern fn invoke<$($var,)* R>(
a: usize,
b: usize,
$($var: $var),*
) -> R {
if a == 0 {
throw("closure has been destroyed already");
}
let f: &Fn($($var),*) -> R = mem::transmute((a, b));
f($($var),*)
}
unsafe {
let (a, b): (usize, usize) = mem::transmute(self);
extra.push(a as u32);
extra.push(b as u32);
invoke::<$($var,)* R> as u32
}
}
}
impl<'a, $($var,)*> ToRefWasmBoundary for Fn($($var),*) + 'a
where $($var: WasmAbi,)*
{
type Abi = u32;
const DESCRIPTOR: Descriptor = $descriptor;
fn to_abi_ref(&self, extra: &mut Stack) -> u32 {
#[allow(non_snake_case)]
unsafe extern fn invoke<$($var,)* >(
a: usize,
b: usize,
$($var: $var),*
) {
if a == 0 {
throw("closure has been destroyed already");
}
let f: &Fn($($var),*) = mem::transmute((a, b));
f($($var),*)
}
unsafe {
let (a, b): (usize, usize) = mem::transmute(self);
extra.push(a as u32);
extra.push(b as u32);
invoke::<$($var,)*> as u32
}
}
}
)*)
}
stack_closures! {
() => DESCRIPTOR_STACK_FUNC0
(A) => DESCRIPTOR_STACK_FUNC1
(A B) => DESCRIPTOR_STACK_FUNC2
(A B C) => DESCRIPTOR_STACK_FUNC3
(A B C D) => DESCRIPTOR_STACK_FUNC4
(A B C D E) => DESCRIPTOR_STACK_FUNC5
(A B C D E F) => DESCRIPTOR_STACK_FUNC6
(A B C D E F G) => DESCRIPTOR_STACK_FUNC7
}

37
src/lib.rs
View File

@ -5,7 +5,7 @@
//! this crate and this crate also provides JS bindings through the `JsValue` //! this crate and this crate also provides JS bindings through the `JsValue`
//! interface. //! interface.
#![feature(use_extern_macros, wasm_import_module, try_reserve)] #![feature(use_extern_macros, wasm_import_module, try_reserve, unsize)]
extern crate wasm_bindgen_macro; extern crate wasm_bindgen_macro;
@ -23,9 +23,11 @@ use convert::WasmBoundary;
pub mod prelude { pub mod prelude {
pub use wasm_bindgen_macro::wasm_bindgen; pub use wasm_bindgen_macro::wasm_bindgen;
pub use JsValue; pub use JsValue;
pub use closure::Closure;
} }
pub mod convert; pub mod convert;
pub mod closure;
/// Representation of an object owned by JS. /// Representation of an object owned by JS.
/// ///
@ -230,6 +232,17 @@ extern {
fn __wbindgen_is_symbol(idx: u32) -> u32; fn __wbindgen_is_symbol(idx: u32) -> u32;
fn __wbindgen_string_get(idx: u32, len: *mut usize) -> *mut u8; fn __wbindgen_string_get(idx: u32, len: *mut usize) -> *mut u8;
fn __wbindgen_throw(a: *const u8, b: usize) -> !; fn __wbindgen_throw(a: *const u8, b: usize) -> !;
fn __wbindgen_cb_arity0(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity1(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity2(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity3(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity4(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity5(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity6(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_arity7(a: u32, b: u32, c: u32) -> u32;
fn __wbindgen_cb_drop(idx: u32);
fn __wbindgen_cb_forget(idx: u32);
} }
impl Clone for JsValue { impl Clone for JsValue {
@ -341,13 +354,13 @@ pub mod __rt {
/// guard accidental reentrancy, so this vendored version is intended solely /// guard accidental reentrancy, so this vendored version is intended solely
/// to not panic in libstd. Instead when it "panics" it calls our `throw` /// to not panic in libstd. Instead when it "panics" it calls our `throw`
/// function in this crate which raises an error in JS. /// function in this crate which raises an error in JS.
pub struct WasmRefCell<T> { pub struct WasmRefCell<T: ?Sized> {
borrow: Cell<usize>, borrow: Cell<usize>,
value: UnsafeCell<T>, value: UnsafeCell<T>,
} }
impl<T> WasmRefCell<T> { impl<T: ?Sized> WasmRefCell<T> {
pub fn new(value: T) -> WasmRefCell<T> { pub fn new(value: T) -> WasmRefCell<T> where T: Sized {
WasmRefCell { WasmRefCell {
value: UnsafeCell::new(value), value: UnsafeCell::new(value),
borrow: Cell::new(0), borrow: Cell::new(0),
@ -386,17 +399,17 @@ pub mod __rt {
} }
} }
pub fn into_inner(self) -> T { pub fn into_inner(self) -> T where T: Sized {
self.value.into_inner() self.value.into_inner()
} }
} }
pub struct Ref<'b, T: 'b> { pub struct Ref<'b, T: ?Sized + 'b> {
value: &'b T, value: &'b T,
borrow: &'b Cell<usize>, borrow: &'b Cell<usize>,
} }
impl<'b, T> Deref for Ref<'b, T> { impl<'b, T: ?Sized> Deref for Ref<'b, T> {
type Target = T; type Target = T;
#[inline] #[inline]
@ -405,18 +418,18 @@ pub mod __rt {
} }
} }
impl<'b, T> Drop for Ref<'b, T> { impl<'b, T: ?Sized> Drop for Ref<'b, T> {
fn drop(&mut self) { fn drop(&mut self) {
self.borrow.set(self.borrow.get() - 1); self.borrow.set(self.borrow.get() - 1);
} }
} }
pub struct RefMut<'b, T: 'b> { pub struct RefMut<'b, T: ?Sized + 'b> {
value: &'b mut T, value: &'b mut T,
borrow: &'b Cell<usize>, borrow: &'b Cell<usize>,
} }
impl<'b, T> Deref for RefMut<'b, T> { impl<'b, T: ?Sized> Deref for RefMut<'b, T> {
type Target = T; type Target = T;
#[inline] #[inline]
@ -425,14 +438,14 @@ pub mod __rt {
} }
} }
impl<'b, T> DerefMut for RefMut<'b, T> { impl<'b, T: ?Sized> DerefMut for RefMut<'b, T> {
#[inline] #[inline]
fn deref_mut(&mut self) -> &mut T { fn deref_mut(&mut self) -> &mut T {
self.value self.value
} }
} }
impl<'b, T> Drop for RefMut<'b, T> { impl<'b, T: ?Sized> Drop for RefMut<'b, T> {
fn drop(&mut self) { fn drop(&mut self) {
self.borrow.set(0); self.borrow.set(0);
} }

325
tests/closures.rs Normal file
View File

@ -0,0 +1,325 @@
extern crate test_support;
#[test]
fn works() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use std::cell::Cell;
use wasm_bindgen::prelude::*;
#[wasm_bindgen(module = "./test")]
extern {
fn call(a: &Fn());
fn thread(a: &Fn(u32) -> u32) -> u32;
}
#[wasm_bindgen]
pub fn run() {
let a = Cell::new(false);
call(&|| a.set(true));
assert!(a.get());
assert_eq!(thread(&|a| a + 1), 3);
}
"#)
.file("test.ts", r#"
import { run } from "./out";
export function call(a: any) {
a();
}
export function thread(a: any) {
return a(2);
}
export function test() {
run();
}
"#)
.test();
}
#[test]
fn cannot_reuse() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use std::cell::Cell;
use wasm_bindgen::prelude::*;
#[wasm_bindgen(module = "./test")]
extern {
fn call(a: &Fn());
#[wasm_bindgen(catch)]
fn call_again() -> Result<(), JsValue>;
}
#[wasm_bindgen]
pub fn run() {
call(&|| {});
assert!(call_again().is_err());
}
"#)
.file("test.ts", r#"
import { run } from "./out";
let CACHE: any = null;
export function call(a: any) {
CACHE = a;
}
export function call_again() {
CACHE();
}
export function test() {
run();
}
"#)
.test();
}
#[test]
fn long_lived() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use std::cell::Cell;
use wasm_bindgen::prelude::*;
#[wasm_bindgen(module = "./test")]
extern {
fn call1(a: &Closure<Fn()>);
fn call2(a: &Closure<FnMut(u32) -> u32>) -> u32;
}
#[wasm_bindgen]
pub fn run() {
let hit = Cell::new(false);
let a = Closure::new(|| hit.set(true));
assert!(!hit.get());
call1(&a);
assert!(hit.get());
let mut hit = false;
{
let a = Closure::new(|x| {
hit = true;
x + 3
});
assert_eq!(call2(&a), 5);
}
assert!(hit);
}
"#)
.file("test.ts", r#"
import { run } from "./out";
export function call1(a: any) {
a();
}
export function call2(a: any) {
return a(2);
}
export function test() {
run();
}
"#)
.test();
}
#[test]
fn many_arity() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
#[wasm_bindgen(module = "./test")]
extern {
fn call1(a: &Closure<Fn()>);
fn call2(a: &Closure<Fn(u32)>);
fn call3(a: &Closure<Fn(u32, u32)>);
fn call4(a: &Closure<Fn(u32, u32, u32)>);
fn call5(a: &Closure<Fn(u32, u32, u32, u32)>);
fn call6(a: &Closure<Fn(u32, u32, u32, u32, u32)>);
fn call7(a: &Closure<Fn(u32, u32, u32, u32, u32, u32)>);
fn call8(a: &Closure<Fn(u32, u32, u32, u32, u32, u32, u32)>);
#[wasm_bindgen(js_name = call1)]
fn stack1(a: &Fn());
#[wasm_bindgen(js_name = call2)]
fn stack2(a: &Fn(u32));
#[wasm_bindgen(js_name = call3)]
fn stack3(a: &Fn(u32, u32));
#[wasm_bindgen(js_name = call4)]
fn stack4(a: &Fn(u32, u32, u32));
#[wasm_bindgen(js_name = call5)]
fn stack5(a: &Fn(u32, u32, u32, u32));
#[wasm_bindgen(js_name = call6)]
fn stack6(a: &Fn(u32, u32, u32, u32, u32));
#[wasm_bindgen(js_name = call7)]
fn stack7(a: &Fn(u32, u32, u32, u32, u32, u32));
#[wasm_bindgen(js_name = call8)]
fn stack8(a: &Fn(u32, u32, u32, u32, u32, u32, u32));
}
#[wasm_bindgen]
pub fn run() {
call1(&Closure::new(|| {}));
call2(&Closure::new(|a| assert_eq!(a, 1)));
call3(&Closure::new(|a, b| assert_eq!((a, b), (1, 2))));
call4(&Closure::new(|a, b, c| assert_eq!((a, b, c), (1, 2, 3))));
call5(&Closure::new(|a, b, c, d| {
assert_eq!((a, b, c, d), (1, 2, 3, 4))
}));
call6(&Closure::new(|a, b, c, d, e| {
assert_eq!((a, b, c, d, e), (1, 2, 3, 4, 5))
}));
call7(&Closure::new(|a, b, c, d, e, f| {
assert_eq!((a, b, c, d, e, f), (1, 2, 3, 4, 5, 6))
}));
call8(&Closure::new(|a, b, c, d, e, f, g| {
assert_eq!((a, b, c, d, e, f, g), (1, 2, 3, 4, 5, 6, 7))
}));
stack1(&(|| {}));
stack2(&(|a| assert_eq!(a, 1)));
stack3(&(|a, b| assert_eq!((a, b), (1, 2))));
stack4(&(|a, b, c| assert_eq!((a, b, c), (1, 2, 3))));
stack5(&(|a, b, c, d| {
assert_eq!((a, b, c, d), (1, 2, 3, 4))
}));
stack6(&(|a, b, c, d, e| {
assert_eq!((a, b, c, d, e), (1, 2, 3, 4, 5))
}));
stack7(&(|a, b, c, d, e, f| {
assert_eq!((a, b, c, d, e, f), (1, 2, 3, 4, 5, 6))
}));
stack8(&(|a, b, c, d, e, f, g| {
assert_eq!((a, b, c, d, e, f, g), (1, 2, 3, 4, 5, 6, 7))
}));
}
"#)
.file("test.ts", r#"
import { run } from "./out";
export function call1(a: any) { a() }
export function call2(a: any) { a(1) }
export function call3(a: any) { a(1, 2) }
export function call4(a: any) { a(1, 2, 3) }
export function call5(a: any) { a(1, 2, 3, 4) }
export function call6(a: any) { a(1, 2, 3, 4, 5) }
export function call7(a: any) { a(1, 2, 3, 4, 5, 6) }
export function call8(a: any) { a(1, 2, 3, 4, 5, 6, 7) }
export function test() {
run();
}
"#)
.test();
}
#[test]
fn long_lived_dropping() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use std::cell::Cell;
use wasm_bindgen::prelude::*;
#[wasm_bindgen(module = "./test")]
extern {
fn cache(a: &Closure<Fn()>);
#[wasm_bindgen(catch)]
fn call() -> Result<(), JsValue>;
}
#[wasm_bindgen]
pub fn run() {
let hit = Cell::new(false);
let a = Closure::new(|| hit.set(true));
cache(&a);
assert!(!hit.get());
assert!(call().is_ok());
assert!(hit.get());
drop(a);
assert!(call().is_err());
}
"#)
.file("test.ts", r#"
import { run } from "./out";
let CACHE: any = null;
export function cache(a: any) { CACHE = a; }
export function call() { CACHE() }
export function test() {
run();
}
"#)
.test();
}
#[test]
fn long_fnmut_recursive() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use std::cell::Cell;
use wasm_bindgen::prelude::*;
#[wasm_bindgen(module = "./test")]
extern {
fn cache(a: &Closure<FnMut()>);
#[wasm_bindgen(catch)]
fn call() -> Result<(), JsValue>;
}
#[wasm_bindgen]
pub fn run() {
let a = Closure::new(|| {
assert!(call().is_err());
});
cache(&a);
assert!(call().is_ok());
}
"#)
.file("test.ts", r#"
import { run } from "./out";
let CACHE: any = null;
export function cache(a: any) { CACHE = a; }
export function call() { CACHE() }
export function test() {
run();
}
"#)
.test();
}