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Support passing JS objects through Rust

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This commit is contained in:
Alex Crichton 2017-12-19 09:25:41 -08:00
parent eda9beae25
commit 946e5317fe
9 changed files with 436 additions and 13 deletions
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18
README.md
View File

@ -17,10 +17,10 @@ Notable features of this project includes:
* Exposing Rust functions to JS
* Managing arguments between JS/Rust (strings, numbers, classes, etc)
* Importing JS functions with richer types (strings)
* Receiving arbitrary JS objects in Rust, passing them through to JS
Planned features include:
* Receiving arbitrary JS objects in Rust
* An optional flag to generate Typescript bindings
* Field setters/getters in JS through Rust functions
* ... and more coming soon!
@ -240,20 +240,21 @@ wasm_bindgen! {
pub struct Bar {
contents: u32,
opaque: JsObject, // defined in `wasm_bindgen`, imported via prelude
}
extern "JS" {
fn bar_on_reset(to: &str);
fn bar_on_reset(to: &str, opaque: &JsObject);
}
impl Bar {
pub fn from_str(s: &str) -> Bar {
Bar { contents: s.parse().unwrap_or(0) }
pub fn from_str(s: &str, opaque: JsObject) -> Bar {
Bar { contents: s.parse().unwrap_or(0), opaque }
}
pub fn reset(&mut self, s: &str) {
if let Ok(n) = s.parse() {
bar_on_reset(s);
bar_on_reset(s, &self.opaque);
self.contents = n;
}
}
@ -282,8 +283,9 @@ and this can be worked with similarly to above with:
.then(bytes => {
return instantiate(bytes, {
env: {
bar_on_reset(s) {
console.log(`an instance of bar was reset to ${s}`);
bar_on_reset(s, token) {
console.log(token);
console.log(`this instance of bar was reset to ${s}`);
},
}
});
@ -301,7 +303,7 @@ and this can be worked with similarly to above with:
// Pass objects to one another
let foo1 = mod.Foo.new();
let bar = mod.Bar.from_str("22");
let bar = mod.Bar.from_str("22", { opaque: 'object' });
foo1.add_other(bar);
// We also don't have to `free` the `bar` variable as this function is

3
crates/test-support/src/lib.rs
View File

@ -55,6 +55,8 @@ pub fn project() -> Project {
out.instantiate(wasm, test.imports).then(m => {
test.test(m);
if (m.assertHeapAndStackEmpty)
m.assertHeapAndStackEmpty();
}).catch(function(error) {
console.error(error);
process.exit(1);
@ -146,6 +148,7 @@ impl Project {
let obj = cli::Bindgen::new()
.input_path(&out)
.nodejs(true)
.debug(true)
.generate()
.expect("failed to run bindgen");
obj.write_js_to(root.join("out.js")).expect("failed to write js");

127
crates/wasm-bindgen-cli-support/src/js.rs
View File

@ -9,10 +9,12 @@ pub struct Js {
expose_assert_num: bool,
expose_assert_class: bool,
expose_token: bool,
expose_objects: bool,
exports: Vec<(String, String)>,
classes: Vec<String>,
imports: Vec<String>,
pub nodejs: bool,
pub debug: bool,
}
impl Js {
@ -149,11 +151,31 @@ impl Js {
", i = i, arg = name, struct_ = s));
pass(&format!("ptr{}", i));
}
shared::Type::JsObject => {
self.expose_objects = true;
arg_conversions.push_str(&format!("\
const idx{i} = addHeapObject({arg});
", i = i, arg = name));
pass(&format!("idx{}", i));
}
shared::Type::JsObjectRef => {
self.expose_objects = true;
arg_conversions.push_str(&format!("\
const idx{i} = addBorrowedObject({arg});
", i = i, arg = name));
destructors.push_str("popBorrowedObject();\n");
pass(&format!("idx{}", i));
}
}
}
let convert_ret = match ret {
None |
Some(&shared::Type::Number) => format!("return ret;"),
Some(&shared::Type::JsObject) => {
self.expose_objects = true;
format!("return takeObject(ret);")
}
Some(&shared::Type::JsObjectRef) |
Some(&shared::Type::BorrowedStr) |
Some(&shared::Type::ByMutRef(_)) |
Some(&shared::Type::ByRef(_)) => panic!(),
@ -221,6 +243,16 @@ impl Js {
invocation.push_str(&format!("getStringFromWasm(ptr{0}, len{0})", i));
dst.push_str(&format!("ptr{0}, len{0}", i));
}
shared::Type::JsObject => {
self.expose_objects = true;
invocation.push_str(&format!("takeObject(arg{})", i));
dst.push_str(&format!("arg{}", i));
}
shared::Type::JsObjectRef => {
self.expose_objects = true;
invocation.push_str(&format!("getObject(arg{})", i));
dst.push_str(&format!("arg{}", i));
}
shared::Type::String |
shared::Type::ByRef(_) |
shared::Type::ByMutRef(_) |
@ -235,7 +267,7 @@ impl Js {
self.imports.push(dst);
}
pub fn to_string(&self) -> String {
pub fn to_string(&mut self) -> String {
let mut globals = String::new();
let mut real_globals = String::new();
if self.expose_global_memory ||
@ -328,6 +360,92 @@ impl Js {
");
}
if self.expose_objects {
real_globals.push_str("
let stack = [];
let slab = [];
let slab_next = 0;
function addHeapObject(obj) {
if (slab_next == slab.length) {
slab.push(slab.length + 1);
}
const idx = slab_next;
slab_next = slab[idx];
slab[idx] = { obj, cnt: 1 };
return idx << 1;
}
function addBorrowedObject(obj) {
stack.push(obj);
return ((stack.length - 1) << 1) | 1;
}
function popBorrowedObject() {
stack.pop();
}
function getObject(idx) {
if (idx & 1 == 1) {
return stack[idx >> 1];
} else {
return slab[idx >> 1].obj;
}
}
function takeObject(idx) {
const ret = getObject(idx);
dropRef(idx);
return ret;
}
function cloneRef(idx) {
// If this object is on the stack promote it to the heap.
if (idx & 1 == 1) {
return addHeapObject(getObject(idx));
}
// Otherwise if the object is on the heap just bump the
// refcount and move on
slab[idx >> 1].cnt += 1;
return idx;
}
function dropRef(idx) {
if (idx & 1 == 1)
throw new Error('cannot drop ref of stack objects');
// Decrement our refcount, but if it's still larger than one
// keep going
let obj = slab[idx >> 1];
obj.cnt -= 1;
if (obj.cnt > 0)
return;
// If we hit 0 then free up our space in the slab
slab[idx >> 1] = slab_next;
slab_next = idx >> 1;
}
");
if self.debug {
self.exports.push(
(
"assertHeapAndStackEmpty".to_string(),
"function() {
if (stack.length > 0)
throw new Error('stack is not empty');
for (let i = 0; i < slab.length; i++) {
if (typeof(slab[i]) !== 'number')
throw new Error('slab is not empty');
}
}".to_string(),
)
);
}
}
let mut exports = String::new();
for class in self.classes.iter() {
exports.push_str(class);
@ -345,6 +463,13 @@ impl Js {
imports.push_str(import);
imports.push_str("\n");
}
if self.expose_objects {
imports.push_str("
imports.env.__wasm_bindgen_object_clone_ref = cloneRef;
imports.env.__wasm_bindgen_object_drop_ref = dropRef;
");
}
format!("
{}
function xform(obj) {{

10
crates/wasm-bindgen-cli-support/src/lib.rs
View File

@ -16,12 +16,14 @@ mod js;
pub struct Bindgen {
path: Option<PathBuf>,
nodejs: bool,
debug: bool,
}
pub struct Object {
module: Module,
program: shared::Program,
nodejs: bool,
debug: bool,
}
impl Bindgen {
@ -29,6 +31,7 @@ impl Bindgen {
Bindgen {
path: None,
nodejs: false,
debug: false,
}
}
@ -42,6 +45,11 @@ impl Bindgen {
self
}
pub fn debug(&mut self, debug: bool) -> &mut Bindgen {
self.debug = debug;
self
}
pub fn generate(&mut self) -> Result<Object, Error> {
let input = match self.path {
Some(ref path) => path,
@ -55,6 +63,7 @@ impl Bindgen {
module,
program,
nodejs: self.nodejs,
debug: self.debug,
})
}
}
@ -89,6 +98,7 @@ impl Object {
pub fn generate_js(&self) -> String {
let mut js = js::Js::default();
js.nodejs = self.nodejs;
js.debug = self.debug;
js.generate_program(&self.program);
js.to_string()
}

9
crates/wasm-bindgen-macro/src/ast.rs
View File

@ -29,6 +29,8 @@ pub enum Type {
ByValue(syn::Ident),
ByRef(syn::Ident),
ByMutRef(syn::Ident),
JsObject,
JsObjectRef,
}
pub struct Struct {
@ -227,6 +229,10 @@ impl Type {
}
Type::BorrowedStr
}
"JsObject" if !mutable => Type::JsObjectRef,
"JsObject" if mutable => {
panic!("can't have mutable js object refs")
}
_ if mutable => Type::ByMutRef(ident),
_ => Type::ByRef(ident),
}
@ -250,6 +256,7 @@ impl Type {
Type::Integer(ident)
}
"String" => Type::String,
"JsObject" => Type::JsObject,
_ => Type::ByValue(ident),
}
}
@ -265,6 +272,8 @@ impl Type {
Type::ByValue(n) => shared::Type::ByValue(n.to_string()),
Type::ByRef(n) => shared::Type::ByRef(n.to_string()),
Type::ByMutRef(n) => shared::Type::ByMutRef(n.to_string()),
Type::JsObject => shared::Type::JsObject,
Type::JsObjectRef => shared::Type::JsObjectRef,
}
}
}

49
crates/wasm-bindgen-macro/src/lib.rs
View File

@ -101,7 +101,7 @@ pub fn wasm_bindgen(input: TokenStream) -> TokenStream {
*#generated_static_value;
}).to_tokens(&mut ret);
println!("{}", ret);
// println!("{}", ret);
ret.into()
}
@ -241,6 +241,21 @@ fn bindgen(export_name: &syn::Lit,
let #ident = &mut *#ident;
});
}
ast::Type::JsObject => {
args.push(my_quote! { #ident: u32 });
arg_conversions.push(my_quote! {
let #ident = ::wasm_bindgen::JsObject::__from_idx(#ident);
});
}
ast::Type::JsObjectRef => {
args.push(my_quote! { #ident: u32 });
arg_conversions.push(my_quote! {
let #ident = ::std::mem::ManuallyDrop::new(
::wasm_bindgen::JsObject::__from_idx(#ident)
);
let #ident = &*#ident;
});
}
}
converted_arguments.push(my_quote! { #ident });
}
@ -265,6 +280,15 @@ fn bindgen(export_name: &syn::Lit,
Box::into_raw(Box::new(::std::cell::RefCell::new(#ret)))
};
}
Some(&ast::Type::JsObject) => {
ret_ty = my_quote! { -> u32 };
convert_ret = my_quote! {
::wasm_bindgen::JsObject::__into_idx(#ret)
};
}
Some(&ast::Type::JsObjectRef) => {
panic!("can't return a borrowed ref");
}
None => {
ret_ty = my_quote! {};
convert_ret = my_quote! {};
@ -407,11 +431,25 @@ fn bindgen_import(import: &ast::Import, tokens: &mut Tokens) {
let #len = #name.len();
});
}
ast::Type::JsObject => {
abi_argument_names.push(name);
abi_arguments.push(my_quote! { #name: u32 });
arg_conversions.push(my_quote! {
let #name = ::wasm_bindgen::JsObject::__into_idx(#name);
});
}
ast::Type::JsObjectRef => {
abi_argument_names.push(name);
abi_arguments.push(my_quote! { #name: u32 });
arg_conversions.push(my_quote! {
let #name = ::wasm_bindgen::JsObject::__get_idx(#name);
});
}
ast::Type::String => panic!("can't use `String` in foreign functions"),
ast::Type::ByValue(_name) |
ast::Type::ByRef(_name) |
ast::Type::ByMutRef(_name) => {
panic!("can't use strct types in foreign functions yet");
panic!("can't use struct types in foreign functions yet");
}
}
}
@ -422,6 +460,13 @@ fn bindgen_import(import: &ast::Import, tokens: &mut Tokens) {
abi_ret = my_quote! { #i };
convert_ret = my_quote! { #ret_ident };
}
Some(ast::Type::JsObject) => {
abi_ret = my_quote! { u32 };
convert_ret = my_quote! {
::wasm_bindgen::JsObject::__from_idx(#ret_ident)
};
}
Some(ast::Type::JsObjectRef) => panic!("can't return a borrowed ref"),
Some(ast::Type::BorrowedStr) => panic!("can't return a borrowed string"),
Some(ast::Type::ByRef(_)) => panic!("can't return a borrowed ref"),
Some(ast::Type::ByMutRef(_)) => panic!("can't return a borrowed ref"),

2
crates/wasm-bindgen-shared/src/lib.rs
View File

@ -63,6 +63,8 @@ pub enum Type {
ByValue(String),
ByRef(String),
ByMutRef(String),
JsObject,
JsObjectRef,
}
impl Type {

47
src/lib.rs
View File

@ -2,11 +2,54 @@
extern crate wasm_bindgen_macro;
use std::mem;
pub mod prelude {
pub use wasm_bindgen_macro::wasm_bindgen;
pub use Object;
pub use JsObject;
}
pub struct Object {
pub struct JsObject {
idx: u32,
}
impl JsObject {
#[doc(hidden)]
pub fn __from_idx(idx: u32) -> JsObject {
JsObject { idx }
}
#[doc(hidden)]
pub fn __get_idx(&self) -> u32 {
self.idx
}
#[doc(hidden)]
pub fn __into_idx(self) -> u32 {
let ret = self.idx;
mem::forget(self);
return ret
}
}
extern {
fn __wasm_bindgen_object_clone_ref(idx: u32) -> u32;
fn __wasm_bindgen_object_drop_ref(idx: u32);
}
impl Clone for JsObject {
fn clone(&self) -> JsObject {
unsafe {
let idx = __wasm_bindgen_object_clone_ref(self.idx);
JsObject { idx }
}
}
}
impl Drop for JsObject {
fn drop(&mut self) {
unsafe {
__wasm_bindgen_object_drop_ref(self.idx);
}
}
}

184
tests/jsobjects.rs Normal file
View File

@ -0,0 +1,184 @@
extern crate test_support;
#[test]
fn simple() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
wasm_bindgen! {
extern "JS" {
fn foo(s: &JsObject);
}
pub fn bar(s: &JsObject) {
foo(s);
}
}
"#)
.file("test.js", r#"
import * as assert from "assert";
let ARG = null;
export const imports = {
env: {
foo(s) {
assert.strictEqual(ARG, null);
ARG = s;
},
},
};
export function test(wasm) {
assert.strictEqual(ARG, null);
let sym = Symbol('test');
wasm.bar(sym);
assert.strictEqual(ARG, sym);
}
"#)
.test();
}
#[test]
fn owned() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
wasm_bindgen! {
extern "JS" {
fn foo(s: JsObject);
}
pub fn bar(s: JsObject) {
foo(s);
}
}
"#)
.file("test.js", r#"
import * as assert from "assert";
let ARG = null;
export const imports = {
env: {
foo(s) {
assert.strictEqual(ARG, null);
ARG = s;
},
},
};
export function test(wasm) {
assert.strictEqual(ARG, null);
let sym = Symbol('test');
wasm.bar(sym);
assert.strictEqual(ARG, sym);
}
"#)
.test();
}
#[test]
fn clone() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
wasm_bindgen! {
extern "JS" {
fn foo1(s: JsObject);
fn foo2(s: &JsObject);
fn foo3(s: JsObject);
fn foo4(s: &JsObject);
fn foo5(s: JsObject);
}
pub fn bar(s: JsObject) {
foo1(s.clone());
foo2(&s);
foo3(s.clone());
foo4(&s);
foo5(s);
}
}
"#)
.file("test.js", r#"
import * as assert from "assert";
let ARG = Symbol('test');
export const imports = {
env: {
foo1(s) { assert.strictEqual(s, ARG); },
foo2(s) { assert.strictEqual(s, ARG); },
foo3(s) { assert.strictEqual(s, ARG); },
foo4(s) { assert.strictEqual(s, ARG); },
foo5(s) { assert.strictEqual(s, ARG); },
},
};
export function test(wasm) {
wasm.bar(ARG);
}
"#)
.test();
}
#[test]
fn promote() {
test_support::project()
.file("src/lib.rs", r#"
#![feature(proc_macro)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
wasm_bindgen! {
extern "JS" {
fn foo1(s: &JsObject);
fn foo2(s: JsObject);
fn foo3(s: &JsObject);
fn foo4(s: JsObject);
}
pub fn bar(s: &JsObject) {
foo1(s);
foo2(s.clone());
foo3(s);
foo4(s.clone());
}
}
"#)
.file("test.js", r#"
import * as assert from "assert";
let ARG = Symbol('test');
export const imports = {
env: {
foo1(s) { assert.strictEqual(s, ARG); },
foo2(s) { assert.strictEqual(s, ARG); },
foo3(s) { assert.strictEqual(s, ARG); },
foo4(s) { assert.strictEqual(s, ARG); },
},
};
export function test(wasm) {
wasm.bar(ARG);
}
"#)
.test();
}