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Merge pull request #127 from konstin/new

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Support `new Foo(...)` to fix #115
This commit is contained in:
Alex Crichton 2018-04-16 09:49:19 -05:00 committed by GitHub
commit c1df44189e
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5 changed files with 211 additions and 86 deletions
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48
DESIGN.md
View File

@ -536,31 +536,37 @@ available to JS through generated shims. If we take a look at the generated JS
code for this we'll see:
```js
import * as wasm from './foo_bg';
import * as wasm from './js_hello_world_bg';
export class Foo {
constructor(ptr) {
this.ptr = ptr;
}
static __construct(ptr) {
return new Foo(ptr);
}
free() {
const ptr = this.ptr;
this.ptr = 0;
wasm.__wbindgen_foo_free(ptr);
}
constructor(ptr) {
this.ptr = ptr;
}
static new(arg0) {
const ret = wasm.foo_new(arg0);
return new Foo(ret);
}
free() {
const ptr = this.ptr;
this.ptr = 0;
wasm.__wbg_foo_free(ptr);
}
get() {
return wasm.foo_get(this.ptr);
}
static new(arg0) {
const ret = wasm.foo_new(arg0);
return Foo.__construct(ret)
}
set(arg0) {
wasm.foo_set(this.ptr, arg0);
}
get() {
const ret = wasm.foo_get(this.ptr);
return ret;
}
set(arg0) {
const ret = wasm.foo_set(this.ptr, arg0);
return ret;
}
}
```
@ -573,9 +579,7 @@ to JS:
* Manual memory management is exposed in JS as well. The `free` function is
required to be invoked to deallocate resources on the Rust side of things.
It's intended that `new Foo()` is never used in JS. When `wasm-bindgen` is run
with `--debug` it'll actually emit assertions to this effect to ensure that
instances of `Foo` are only constructed with the functions like `Foo.new` in JS.
To be able to use `new Foo()`, you'd need to annotate `new` as `#[wasm_bindgen(constructor)]`.
One important aspect to note here, though, is that once `free` is called the JS
object is "neutered" in that its internal pointer is nulled out. This means that

32
crates/backend/src/ast.rs
View File

@ -14,6 +14,7 @@ pub struct Export {
pub class: Option<syn::Ident>,
pub method: bool,
pub mutable: bool,
pub constructor: Option<String>,
pub function: Function,
}
@ -116,6 +117,7 @@ impl Program {
class: None,
method: false,
mutable: false,
constructor: None,
function: Function::from(f, opts),
});
}
@ -126,8 +128,8 @@ impl Program {
}
syn::Item::Impl(mut i) => {
let opts = opts.unwrap_or_else(|| BindgenAttrs::find(&mut i.attrs));
self.push_impl(&mut i, opts);
i.to_tokens(tokens);
self.push_impl(i, opts);
}
syn::Item::ForeignMod(mut f) => {
let opts = opts.unwrap_or_else(|| BindgenAttrs::find(&mut f.attrs));
@ -145,7 +147,7 @@ impl Program {
}
}
pub fn push_impl(&mut self, item: syn::ItemImpl, _opts: BindgenAttrs) {
pub fn push_impl(&mut self, item: &mut syn::ItemImpl, _opts: BindgenAttrs) {
if item.defaultness.is_some() {
panic!("default impls are not supported");
}
@ -168,16 +170,16 @@ impl Program {
},
_ => panic!("unsupported self type in impl"),
};
for item in item.items.into_iter() {
self.push_impl_item(name, item);
for mut item in item.items.iter_mut() {
self.push_impl_item(name, &mut item);
}
}
fn push_impl_item(&mut self, class: syn::Ident, item: syn::ImplItem) {
let mut method = match item {
fn push_impl_item(&mut self, class: syn::Ident, item: &mut syn::ImplItem) {
let method = match item {
syn::ImplItem::Const(_) => panic!("const definitions aren't supported"),
syn::ImplItem::Type(_) => panic!("type definitions in impls aren't supported"),
syn::ImplItem::Method(m) => m,
syn::ImplItem::Method(ref mut m) => m,
syn::ImplItem::Macro(_) => panic!("macros in impls aren't supported"),
syn::ImplItem::Verbatim(_) => panic!("unparsed impl item?"),
};
@ -196,19 +198,27 @@ impl Program {
}
let opts = BindgenAttrs::find(&mut method.attrs);
let is_constructor = opts.constructor();
let constructor = if is_constructor {
Some(method.sig.ident.to_string())
} else {
None
};
let (function, mutable) = Function::from_decl(
method.sig.ident,
Box::new(method.sig.decl),
method.attrs,
Box::new(method.sig.decl.clone()),
method.attrs.clone(),
opts,
method.vis,
method.vis.clone(),
true,
);
self.exports.push(Export {
class: Some(class),
method: mutable.is_some(),
mutable: mutable.unwrap_or(false),
constructor,
function,
});
}
@ -536,6 +546,7 @@ impl Export {
shared::Export {
class: self.class.map(|s| s.as_ref().to_string()),
method: self.method,
constructor: self.constructor.clone(),
function: self.function.shared(),
}
}
@ -764,6 +775,7 @@ impl syn::synom::Synom for BindgenAttrs {
));
}
#[derive(PartialEq)]
enum BindgenAttr {
Catch,
Constructor,

132
crates/cli-support/src/js.rs
View File

@ -29,6 +29,7 @@ pub struct Context<'a> {
pub struct ExportedClass {
pub contents: String,
pub typescript: String,
pub constructor: Option<String>,
}
pub struct SubContext<'a, 'b: 'a> {
@ -316,42 +317,57 @@ impl<'a> Context<'a> {
ts_dst.push_str("
public ptr: number;
");
if self.config.debug {
self.expose_check_token();
dst.push_str(&format!("
constructor(ptr, sym) {{
_checkToken(sym);
this.ptr = ptr;
}}
"));
ts_dst.push_str("constructor(ptr: number, sym: Symbol);\n");
let new_name = shared::new_function(&class);
if self.wasm_import_needed(&new_name) {
self.expose_add_heap_object();
self.export(&new_name, &format!("
function(ptr) {{
return addHeapObject(new {class}(ptr, token));
if self.config.debug || exports.constructor.is_some() {
self.expose_constructor_token();
dst.push_str(&format!("
static __construct(ptr) {{
return new {}(new ConstructorToken(ptr));
}}
constructor(...args) {{
if (args.length === 1 && args[0] instanceof ConstructorToken) {{
this.ptr = args[0].ptr;
return;
}}
", class = class));
", class));
if let Some(constructor) = exports.constructor {
ts_dst.push_str(&format!("constructor(...args: [any]);\n"));
dst.push_str(&format!("
// This invocation of new will call this constructor with a ConstructorToken
let instance = {class}.{constructor}(...args);
this.ptr = instance.ptr;
", class = class, constructor = constructor));
} else {
dst.push_str("throw new Error('you cannot invoke `new` directly without having a \
method annotated a constructor');");
}
dst.push_str("}");
} else {
dst.push_str(&format!("
static __construct(ptr) {{
return new {}(ptr);
}}
constructor(ptr) {{
this.ptr = ptr;
}}
"));
ts_dst.push_str("constructor(ptr: number);\n");
", class));
}
let new_name = shared::new_function(&class);
if self.wasm_import_needed(&new_name) {
self.expose_add_heap_object();
self.export(&new_name, &format!("
function(ptr) {{
return addHeapObject(new {class}(ptr));
}}
", class = class));
}
let new_name = shared::new_function(&class);
if self.wasm_import_needed(&new_name) {
self.expose_add_heap_object();
self.export(&new_name, &format!("
function(ptr) {{
return addHeapObject({}.__construct(ptr));
}}
", class));
}
dst.push_str(&format!("
@ -589,19 +605,6 @@ impl<'a> Context<'a> {
", get_obj));
}
fn expose_check_token(&mut self) {
if !self.exposed_globals.insert("check_token") {
return;
}
self.globals.push_str(&format!("
const token = Symbol('foo');
function _checkToken(sym) {{
if (token !== sym)
throw new Error('cannot invoke `new` directly');
}}
"));
}
fn expose_assert_num(&mut self) {
if !self.exposed_globals.insert("assert_num") {
return;
@ -765,6 +768,20 @@ impl<'a> Context<'a> {
"));
}
fn expose_constructor_token(&mut self) {
if !self.exposed_globals.insert("ConstructorToken") {
return;
}
self.globals.push_str("
class ConstructorToken {
constructor(ptr) {
this.ptr = ptr;
}
}
");
}
fn expose_get_string_from_wasm(&mut self) {
if !self.exposed_globals.insert("get_string_from_wasm") {
return;
@ -1236,11 +1253,8 @@ impl<'a> Context<'a> {
if let Some(name) = ty.rust_struct() {
dst_ts.push_str(": ");
dst_ts.push_str(name);
return if self.config.debug {
format!("return new {name}(ret, token);", name = name)
} else {
format!("return new {name}(ret);", name = name)
}
return format!("return {}.__construct(ret)",&name);
}
if ty.is_number() {
@ -1324,8 +1338,8 @@ impl<'a, 'b> SubContext<'a, 'b> {
self.cx.typescript.push_str("\n");
}
pub fn generate_export_for_class(&mut self, class: &str, export: &shared::Export) {
let wasm_name = shared::struct_function_export_name(class, &export.function.name);
pub fn generate_export_for_class(&mut self, class_name: &str, export: &shared::Export) {
let wasm_name = shared::struct_function_export_name(class_name, &export.function.name);
let descriptor = self.cx.describe(&wasm_name);
let (js, ts) = self.generate_function(
"",
@ -1334,12 +1348,26 @@ impl<'a, 'b> SubContext<'a, 'b> {
export.method,
&descriptor.unwrap_function(),
);
let class = self.cx.exported_classes.entry(class.to_string())
let class = self.cx.exported_classes.entry(class_name.to_string())
.or_insert(ExportedClass::default());
if !export.method {
class.contents.push_str("static ");
class.typescript.push_str("static ");
}
let constructors: Vec<String> = self.program.exports
.iter()
.filter(|x| x.class == Some(class_name.to_string()))
.filter_map(|x| x.constructor.clone())
.collect();
class.constructor = match constructors.len() {
0 => None,
1 => Some(constructors[0].clone()),
x @ _ => panic!("There must be only one constructor, not {}", x),
};
class.contents.push_str(&export.function.name);
class.contents.push_str(&js);
class.contents.push_str("\n");
@ -1560,15 +1588,11 @@ impl<'a, 'b> SubContext<'a, 'b> {
continue
}
if let Some(s) = arg.rust_struct() {
if let Some(class) = arg.rust_struct() {
if arg.is_by_ref() {
panic!("cannot invoke JS functions with custom ref types yet")
}
let assign = if self.cx.config.debug {
format!("let c{0} = new {class}(arg{0}, token);", i, class = s)
} else {
format!("let c{0} = new {class}(arg{0});", i, class = s)
};
let assign = format!("let c{0} = {1}.__construct(arg{0});", i, class);
extra.push_str(&assign);
invoc_args.push(format!("c{}", i));
continue

1
crates/shared/src/lib.rs
View File

@ -54,6 +54,7 @@ pub struct ImportType {
pub struct Export {
pub class: Option<String>,
pub method: bool,
pub constructor: Option<String>,
pub function: Function,
}

84
tests/all/classes.rs
View File

@ -17,6 +17,7 @@ fn simple() {
#[wasm_bindgen]
impl Foo {
#[wasm_bindgen(constructor)]
pub fn new() -> Foo {
Foo::with_contents(0)
}
@ -47,6 +48,10 @@ fn simple() {
assert.strictEqual(r2.add(2), 13);
assert.strictEqual(r2.add(3), 16);
r2.free();
const r3 = new Foo();
assert.strictEqual(r3.add(42), 42);
r3.free();
}
"#)
.test();
@ -361,3 +366,82 @@ fn pass_into_js_as_js_class() {
"#)
.test();
}
#[test]
fn constructors() {
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]
pub fn cross_item_construction() -> Bar {
Bar::other_name(7, 8)
}
#[wasm_bindgen]
pub struct Foo {
number: u32,
}
#[wasm_bindgen]
impl Foo {
#[wasm_bindgen(constructor)]
pub fn new(number: u32) -> Foo {
Foo { number }
}
pub fn get_number(&self) -> u32 {
self.number
}
}
#[wasm_bindgen]
pub struct Bar {
number: u32,
number2: u32,
}
#[wasm_bindgen]
impl Bar {
#[wasm_bindgen(constructor)]
pub fn other_name(number: u32, number2: u32) -> Bar {
Bar { number, number2 }
}
pub fn get_sum(&self) -> u32 {
self.number + self.number2
}
}
"#)
.file("test.ts", r#"
import * as assert from "assert";
import { Foo, Bar, cross_item_construction } from "./out";
export function test() {
const foo = new Foo(1);
assert.strictEqual(foo.get_number(), 1);
foo.free();
const foo2 = Foo.new(2);
assert.strictEqual(foo2.get_number(), 2);
foo2.free();
const bar = new Bar(3, 4);
assert.strictEqual(bar.get_sum(), 7);
bar.free();
const bar2 = Bar.other_name(5, 6);
assert.strictEqual(bar2.get_sum(), 11);
bar2.free();
assert.strictEqual(cross_item_construction().get_sum(), 15);
}
"#)
.test();
}