wasm-bindgen-rayon and new OMT plugin (#1007)

* WIP: wasm-bindgen-rayon and new OMT plugin

* Bump package-lock

* Make OMT work again

* Update year

* Restore accidental change

* Prevent minification of `nextDefineUri`

* Delay loading external deps

This gives inline `define` calls a chance to define dependencies for earlier `define` calls on the same page.

* Add comment

codecs/oxipng/Cargo.lock

@@ -1,5 +1,7 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
 [[package]]
 name = "adler"
 version = "0.2.3"
@@ -232,6 +234,15 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "js-sys"
+version = "0.3.48"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc9f84f9b115ce7843d60706df1422a916680bfdfcbdb0447c5614ff9d7e4d78"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -350,12 +361,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "once_cell"
-version = "1.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13bd41f508810a131401606d54ac32a467c97172d74ba7662562ebba5ad07fa0"
-
 [[package]]
 name = "oxipng"
 version = "4.0.3"
@@ -401,9 +406,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "a152013215dca273577e18d2bf00fa862b89b24169fb78c4c95aeb07992c9cec"
 dependencies = [
  "unicode-xid",
 ]
@@ -484,24 +489,28 @@ dependencies = [
  "pest",
 ]
 
+[[package]]
+name = "spmc"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "02a8428da277a8e3a15271d79943e80ccc2ef254e78813a166a08d65e4c3ece5"
+
 [[package]]
 name = "squoosh-oxipng"
 version = "0.1.0"
 dependencies = [
- "crossbeam-channel",
  "libdeflater",
  "log",
- "once_cell",
  "oxipng",
- "rayon",
  "wasm-bindgen",
+ "wasm-bindgen-rayon",
 ]
 
 [[package]]
 name = "syn"
-version = "1.0.58"
+version = "1.0.72"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc60a3d73ea6594cd712d830cc1f0390fd71542d8c8cd24e70cc54cdfd5e05d5"
+checksum = "a1e8cdbefb79a9a5a65e0db8b47b723ee907b7c7f8496c76a1770b5c310bab82"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -522,9 +531,9 @@ checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.69"
+version = "0.2.73"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3cd364751395ca0f68cafb17666eee36b63077fb5ecd972bbcd74c90c4bf736e"
+checksum = "83240549659d187488f91f33c0f8547cbfef0b2088bc470c116d1d260ef623d9"
 dependencies = [
  "cfg-if 1.0.0",
  "wasm-bindgen-macro",
@@ -532,9 +541,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-backend"
-version = "0.2.69"
+version = "0.2.73"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1114f89ab1f4106e5b55e688b828c0ab0ea593a1ea7c094b141b14cbaaec2d62"
+checksum = "ae70622411ca953215ca6d06d3ebeb1e915f0f6613e3b495122878d7ebec7dae"
 dependencies = [
  "bumpalo",
  "lazy_static",
@@ -547,9 +556,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.69"
+version = "0.2.73"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a6ac8995ead1f084a8dea1e65f194d0973800c7f571f6edd70adf06ecf77084"
+checksum = "3e734d91443f177bfdb41969de821e15c516931c3c3db3d318fa1b68975d0f6f"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -557,9 +566,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.69"
+version = "0.2.73"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5a48c72f299d80557c7c62e37e7225369ecc0c963964059509fbafe917c7549"
+checksum = "d53739ff08c8a68b0fdbcd54c372b8ab800b1449ab3c9d706503bc7dd1621b2c"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -569,7 +578,19 @@ dependencies = [
 ]
 
 [[package]]
-name = "wasm-bindgen-shared"
-version = "0.2.69"
+name = "wasm-bindgen-rayon"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7e7811dd7f9398f14cc76efd356f98f03aa30419dea46aa810d71e819fc97158"
+checksum = "3069d2a42e7a7e3bfde668f84adb5fbc35701ca2b39b27a064cbd5ede4e78194"
+dependencies = [
+ "js-sys",
+ "rayon",
+ "spmc",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.73"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9a543ae66aa233d14bb765ed9af4a33e81b8b58d1584cf1b47ff8cd0b9e4489"

codecs/oxipng/Cargo.toml

@@ -14,15 +14,13 @@ crate-type = ["cdylib"]
 [dependencies]
 oxipng = { version = "4.0.1", default-features = false, features = ["libdeflater"] }
 libdeflater = { version = "0.7.1", features = ["freestanding"] }
-wasm-bindgen = "0.2.68"
+wasm-bindgen = "0.2.73"
 log = { version = "0.4.11", features = ["release_max_level_off"] }
-rayon = { version = "1.5.0", optional = true }
-once_cell = { version = "1.5.2", optional = true }
-crossbeam-channel = { version = "0.5.0", optional = true }
+wasm-bindgen-rayon = { version = "1.0", optional = true }
 
 [profile.release]
 lto = true
 opt-level = "s"
 
 [features]
-parallel = ["oxipng/parallel", "rayon", "crossbeam-channel", "once_cell"]
+parallel = ["oxipng/parallel", "wasm-bindgen-rayon"]

codecs/oxipng/build.sh

@@ -6,6 +6,4 @@ rm -rf pkg,{-parallel}
 export CFLAGS="${CFLAGS} -DUNALIGNED_ACCESS_IS_FAST=1"
 wasm-pack build -t web
 RUSTFLAGS='-C target-feature=+atomics,+bulk-memory' wasm-pack build -t web -d pkg-parallel -- -Z build-std=panic_abort,std --features=parallel
-# Workaround https://github.com/rustwasm/wasm-bindgen/issues/2133:
-sed -i "s|maybe_memory:|maybe_memory?:|" pkg-parallel/squoosh_oxipng.d.ts
 rm pkg{,-parallel}/.gitignore

codecs/oxipng/pkg-parallel/snippets/wasm-bindgen-rayon-3d2df09ebec17a22/src/workerHelpers.js

@@ -0,0 +1,98 @@
+/**
+ * Copyright 2021 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Note: we use `wasm_bindgen_worker_`-prefixed message types to make sure
+// we can handle bundling into other files, which might happen to have their
+// own `postMessage`/`onmessage` communication channels.
+//
+// If we didn't take that into the account, we could send much simpler signals
+// like just `0` or whatever, but the code would be less resilient.
+
+function waitForMsgType(target, type) {
+  return new Promise(resolve => {
+    target.addEventListener('message', function onMsg({ data }) {
+      if (data == null || data.type !== type) return;
+      target.removeEventListener('message', onMsg);
+      resolve(data);
+    });
+  });
+}
+
+waitForMsgType(self, 'wasm_bindgen_worker_init').then(async data => {
+  // # Note 1
+  // Our JS should have been generated in
+  // `[out-dir]/snippets/wasm-bindgen-rayon-[hash]/workerHelpers.js`,
+  // resolve the main module via `../../..`.
+  //
+  // This might need updating if the generated structure changes on wasm-bindgen
+  // side ever in the future, but works well with bundlers today. The whole
+  // point of this crate, after all, is to abstract away unstable features
+  // and temporary bugs so that you don't need to deal with them in your code.
+  //
+  // # Note 2
+  // This could be a regular import, but then some bundlers complain about
+  // circular deps.
+  //
+  // Dynamic import could be cheap if this file was inlined into the parent,
+  // which would require us just using `../../..` in `new Worker` below,
+  // but that doesn't work because wasm-pack unconditionally adds
+  // "sideEffects":false (see below).
+  //
+  // OTOH, even though it can't be inlined, it should be still reasonably
+  // cheap since the requested file is already in cache (it was loaded by
+  // the main thread).
+  const pkg = await import('../../..');
+  await pkg.default(data.module, data.memory);
+  postMessage({ type: 'wasm_bindgen_worker_ready' });
+  pkg.wbg_rayon_start_worker(data.receiver);
+});
+
+export async function startWorkers(module, memory, builder) {
+  const workerInit = {
+    type: 'wasm_bindgen_worker_init',
+    module,
+    memory,
+    receiver: builder.receiver()
+  };
+
+  try {
+    await Promise.all(
+      Array.from({ length: builder.numThreads() }, () => {
+        // Self-spawn into a new Worker.
+        //
+        // TODO: while `new URL('...', import.meta.url) becomes a semi-standard
+        // way to get asset URLs relative to the module across various bundlers
+        // and browser, ideally we should switch to `import.meta.resolve`
+        // once it becomes a standard.
+        //
+        // Note: we could use `../../..` as the URL here to inline workerHelpers.js
+        // into the parent entry instead of creating another split point -
+        // this would be preferable from optimization perspective -
+        // however, Webpack then eliminates all message handler code
+        // because wasm-pack produces "sideEffects":false in package.json
+        // unconditionally.
+        //
+        // The only way to work around that is to have side effect code
+        // in an entry point such as Worker file itself.
+        const worker = new Worker(new URL('./workerHelpers.js', import.meta.url), {
+          type: 'module'
+        });
+        worker.postMessage(workerInit);
+        return waitForMsgType(worker, 'wasm_bindgen_worker_ready');
+      })
+    );
+    builder.build();
+  } finally {
+    builder.free();
+  }
+}

codecs/oxipng/pkg-parallel/squoosh_oxipng.d.ts

@@ -7,25 +7,43 @@
 */
 export function optimise(data: Uint8Array, level: number): Uint8Array;
 /**
-* @param {number} num
-* @returns {any}
+* @param {number} num_threads
+* @returns {Promise<any>}
 */
-export function worker_initializer(num: number): any;
+export function initThreadPool(num_threads: number): Promise<any>;
+/**
+* @param {number} receiver
+*/
+export function wbg_rayon_start_worker(receiver: number): void;
 /**
 */
-export function start_main_thread(): void;
+export class wbg_rayon_PoolBuilder {
+  free(): void;
+/**
+* @returns {number}
+*/
+  numThreads(): number;
+/**
+* @returns {number}
+*/
+  receiver(): number;
 /**
 */
-export function start_worker_thread(): void;
+  build(): void;
+}
 
 export type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembly.Module;
 
 export interface InitOutput {
   readonly optimise: (a: number, b: number, c: number, d: number) => void;
-  readonly worker_initializer: (a: number) => number;
-  readonly start_main_thread: () => void;
-  readonly start_worker_thread: () => void;
+  readonly __wbg_wbg_rayon_poolbuilder_free: (a: number) => void;
+  readonly wbg_rayon_poolbuilder_numThreads: (a: number) => number;
+  readonly wbg_rayon_poolbuilder_receiver: (a: number) => number;
+  readonly wbg_rayon_poolbuilder_build: (a: number) => void;
+  readonly initThreadPool: (a: number) => number;
+  readonly wbg_rayon_start_worker: (a: number) => void;
   readonly __wbindgen_export_0: WebAssembly.Memory;
+  readonly __wbindgen_add_to_stack_pointer: (a: number) => number;
   readonly __wbindgen_malloc: (a: number) => number;
   readonly __wbindgen_free: (a: number, b: number) => void;
   readonly __wbindgen_start: () => void;
@@ -41,4 +59,3 @@ export interface InitOutput {
 * @returns {Promise<InitOutput>}
 */
 export default function init (module_or_path?: InitInput | Promise<InitInput>, maybe_memory?: WebAssembly.Memory): Promise<InitOutput>;
-        

codecs/oxipng/pkg-parallel/squoosh_oxipng.js

@@ -1,21 +1,6 @@
+import { startWorkers } from './snippets/wasm-bindgen-rayon-3d2df09ebec17a22/src/workerHelpers.js';
 
 let wasm;
-let memory;
-
-const heap = new Array(32).fill(undefined);
-
-heap.push(undefined, null, true, false);
-
-let heap_next = heap.length;
-
-function addHeapObject(obj) {
-    if (heap_next === heap.length) heap.push(heap.length + 1);
-    const idx = heap_next;
-    heap_next = heap[idx];
-
-    heap[idx] = obj;
-    return idx;
-}
 
 let cachedTextDecoder = new TextDecoder('utf-8', { ignoreBOM: true, fatal: true });
 
@@ -33,6 +18,21 @@ function getStringFromWasm0(ptr, len) {
     return cachedTextDecoder.decode(getUint8Memory0().slice(ptr, ptr + len));
 }
 
+const heap = new Array(32).fill(undefined);
+
+heap.push(undefined, null, true, false);
+
+let heap_next = heap.length;
+
+function addHeapObject(obj) {
+    if (heap_next === heap.length) heap.push(heap.length + 1);
+    const idx = heap_next;
+    heap_next = heap[idx];
+
+    heap[idx] = obj;
+    return idx;
+}
+
 let WASM_VECTOR_LEN = 0;
 
 function passArray8ToWasm0(arg, malloc) {
@@ -60,8 +60,7 @@ function getArrayU8FromWasm0(ptr, len) {
 */
 export function optimise(data, level) {
     try {
-        const retptr = wasm.__wbindgen_export_1.value - 16;
-        wasm.__wbindgen_export_1.value = retptr;
+        const retptr = wasm.__wbindgen_add_to_stack_pointer(-16);
         var ptr0 = passArray8ToWasm0(data, wasm.__wbindgen_malloc);
         var len0 = WASM_VECTOR_LEN;
         wasm.optimise(retptr, ptr0, len0, level);
@@ -71,7 +70,7 @@ export function optimise(data, level) {
         wasm.__wbindgen_free(r0, r1 * 1);
         return v1;
     } finally {
-        wasm.__wbindgen_export_1.value += 16;
+        wasm.__wbindgen_add_to_stack_pointer(16);
     }
 }
 
@@ -89,29 +88,66 @@ function takeObject(idx) {
     return ret;
 }
 /**
-* @param {number} num
-* @returns {any}
+* @param {number} num_threads
+* @returns {Promise<any>}
 */
-export function worker_initializer(num) {
-    var ret = wasm.worker_initializer(num);
+export function initThreadPool(num_threads) {
+    var ret = wasm.initThreadPool(num_threads);
     return takeObject(ret);
 }
 
 /**
+* @param {number} receiver
 */
-export function start_main_thread() {
-    wasm.start_main_thread();
+export function wbg_rayon_start_worker(receiver) {
+    wasm.wbg_rayon_start_worker(receiver);
 }
 
 /**
 */
-export function start_worker_thread() {
-    wasm.start_worker_thread();
+export class wbg_rayon_PoolBuilder {
+
+    static __wrap(ptr) {
+        const obj = Object.create(wbg_rayon_PoolBuilder.prototype);
+        obj.ptr = ptr;
+
+        return obj;
+    }
+
+    __destroy_into_raw() {
+        const ptr = this.ptr;
+        this.ptr = 0;
+
+        return ptr;
+    }
+
+    free() {
+        const ptr = this.__destroy_into_raw();
+        wasm.__wbg_wbg_rayon_poolbuilder_free(ptr);
+    }
+    /**
+    * @returns {number}
+    */
+    numThreads() {
+        var ret = wasm.wbg_rayon_poolbuilder_numThreads(this.ptr);
+        return ret >>> 0;
+    }
+    /**
+    * @returns {number}
+    */
+    receiver() {
+        var ret = wasm.wbg_rayon_poolbuilder_receiver(this.ptr);
+        return ret;
+    }
+    /**
+    */
+    build() {
+        wasm.wbg_rayon_poolbuilder_build(this.ptr);
+    }
 }
 
-async function load(module, imports, maybe_memory) {
+async function load(module, imports) {
     if (typeof Response === 'function' && module instanceof Response) {
-        memory = imports.wbg.memory = new WebAssembly.Memory({initial:17,maximum:16384,shared:true});
         if (typeof WebAssembly.instantiateStreaming === 'function') {
             try {
                 return await WebAssembly.instantiateStreaming(module, imports);
@@ -130,7 +166,6 @@ async function load(module, imports, maybe_memory) {
         return await WebAssembly.instantiate(bytes, imports);
 
     } else {
-        memory = imports.wbg.memory = maybe_memory;
         const instance = await WebAssembly.instantiate(module, imports);
 
         if (instance instanceof WebAssembly.Instance) {
@@ -144,10 +179,13 @@ async function load(module, imports, maybe_memory) {
 
 async function init(input, maybe_memory) {
     if (typeof input === 'undefined') {
-        input = import.meta.url.replace(/\.js$/, '_bg.wasm');
+        input = new URL('squoosh_oxipng_bg.wasm', import.meta.url);
     }
     const imports = {};
     imports.wbg = {};
+    imports.wbg.__wbindgen_throw = function(arg0, arg1) {
+        throw new Error(getStringFromWasm0(arg0, arg1));
+    };
     imports.wbg.__wbindgen_module = function() {
         var ret = init.__wbindgen_wasm_module;
         return addHeapObject(ret);
@@ -156,19 +194,18 @@ async function init(input, maybe_memory) {
         var ret = wasm.__wbindgen_export_0;
         return addHeapObject(ret);
     };
-    imports.wbg.__wbg_of_6510501edc06d65e = function(arg0, arg1) {
-        var ret = Array.of(takeObject(arg0), takeObject(arg1));
+    imports.wbg.__wbg_startWorkers_914655bb4d5bb5e1 = function(arg0, arg1, arg2) {
+        var ret = startWorkers(takeObject(arg0), takeObject(arg1), wbg_rayon_PoolBuilder.__wrap(arg2));
         return addHeapObject(ret);
     };
-    imports.wbg.__wbindgen_throw = function(arg0, arg1) {
-        throw new Error(getStringFromWasm0(arg0, arg1));
-    };
 
     if (typeof input === 'string' || (typeof Request === 'function' && input instanceof Request) || (typeof URL === 'function' && input instanceof URL)) {
         input = fetch(input);
     }
 
-    const { instance, module } = await load(await input, imports, maybe_memory);
+    imports.wbg.memory = maybe_memory || new WebAssembly.Memory({initial:17,maximum:16384,shared:true});
+
+    const { instance, module } = await load(await input, imports);
 
     wasm = instance.exports;
     init.__wbindgen_wasm_module = module;

codecs/oxipng/pkg-parallel/squoosh_oxipng_bg.wasm.d.ts

@@ -1,10 +1,14 @@
 /* tslint:disable */
 /* eslint-disable */
 export function optimise(a: number, b: number, c: number, d: number): void;
-export function worker_initializer(a: number): number;
-export function start_main_thread(): void;
-export function start_worker_thread(): void;
+export function __wbg_wbg_rayon_poolbuilder_free(a: number): void;
+export function wbg_rayon_poolbuilder_numThreads(a: number): number;
+export function wbg_rayon_poolbuilder_receiver(a: number): number;
+export function wbg_rayon_poolbuilder_build(a: number): void;
+export function initThreadPool(a: number): number;
+export function wbg_rayon_start_worker(a: number): void;
 export const __wbindgen_export_0: WebAssembly.Memory;
+export function __wbindgen_add_to_stack_pointer(a: number): number;
 export function __wbindgen_malloc(a: number): number;
 export function __wbindgen_free(a: number, b: number): void;
 export function __wbindgen_start(): void;

codecs/oxipng/pkg/squoosh_oxipng.d.ts

@@ -12,6 +12,7 @@ export type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembl
 export interface InitOutput {
   readonly memory: WebAssembly.Memory;
   readonly optimise: (a: number, b: number, c: number, d: number) => void;
+  readonly __wbindgen_add_to_stack_pointer: (a: number) => number;
   readonly __wbindgen_malloc: (a: number) => number;
   readonly __wbindgen_free: (a: number, b: number) => void;
 }
@@ -25,4 +26,3 @@ export interface InitOutput {
 * @returns {Promise<InitOutput>}
 */
 export default function init (module_or_path?: InitInput | Promise<InitInput>): Promise<InitOutput>;
-        

codecs/oxipng/pkg/squoosh_oxipng.js

@@ -44,8 +44,7 @@ function getArrayU8FromWasm0(ptr, len) {
 */
 export function optimise(data, level) {
     try {
-        const retptr = wasm.__wbindgen_export_0.value - 16;
-        wasm.__wbindgen_export_0.value = retptr;
+        const retptr = wasm.__wbindgen_add_to_stack_pointer(-16);
         var ptr0 = passArray8ToWasm0(data, wasm.__wbindgen_malloc);
         var len0 = WASM_VECTOR_LEN;
         wasm.optimise(retptr, ptr0, len0, level);
@@ -55,13 +54,12 @@ export function optimise(data, level) {
         wasm.__wbindgen_free(r0, r1 * 1);
         return v1;
     } finally {
-        wasm.__wbindgen_export_0.value += 16;
+        wasm.__wbindgen_add_to_stack_pointer(16);
     }
 }
 
 async function load(module, imports) {
     if (typeof Response === 'function' && module instanceof Response) {
-
         if (typeof WebAssembly.instantiateStreaming === 'function') {
             try {
                 return await WebAssembly.instantiateStreaming(module, imports);
@@ -80,7 +78,6 @@ async function load(module, imports) {
         return await WebAssembly.instantiate(bytes, imports);
 
     } else {
-
         const instance = await WebAssembly.instantiate(module, imports);
 
         if (instance instanceof WebAssembly.Instance) {
@@ -94,7 +91,7 @@ async function load(module, imports) {
 
 async function init(input) {
     if (typeof input === 'undefined') {
-        input = import.meta.url.replace(/\.js$/, '_bg.wasm');
+        input = new URL('squoosh_oxipng_bg.wasm', import.meta.url);
     }
     const imports = {};
     imports.wbg = {};
@@ -106,6 +103,8 @@ async function init(input) {
         input = fetch(input);
     }
 
+
+
     const { instance, module } = await load(await input, imports);
 
     wasm = instance.exports;

codecs/oxipng/pkg/squoosh_oxipng_bg.wasm.d.ts

@@ -2,5 +2,6 @@
 /* eslint-disable */
 export const memory: WebAssembly.Memory;
 export function optimise(a: number, b: number, c: number, d: number): void;
+export function __wbindgen_add_to_stack_pointer(a: number): number;
 export function __wbindgen_malloc(a: number): number;
 export function __wbindgen_free(a: number, b: number): void;

codecs/oxipng/src/lib.rs

@@ -1,9 +1,9 @@
+#[cfg(feature = "parallel")]
+pub use wasm_bindgen_rayon::init_thread_pool;
+
 use oxipng::AlphaOptim;
 use wasm_bindgen::prelude::*;
 
-#[cfg(feature = "parallel")]
-pub mod parallel;
-
 #[wasm_bindgen]
 pub fn optimise(data: &[u8], level: u8) -> Vec<u8> {
     let mut options = oxipng::Options::from_preset(level);

codecs/oxipng/src/parallel.rs

@@ -1,62 +0,0 @@
-use crossbeam_channel::{bounded, Receiver, Sender};
-use once_cell::sync::OnceCell;
-use wasm_bindgen::prelude::*;
-use wasm_bindgen::JsValue;
-
-#[wasm_bindgen]
-extern "C" {
-    #[wasm_bindgen(js_namespace = Array, js_name = of)]
-    fn array_of_2(a: JsValue, b: JsValue) -> JsValue;
-}
-
-// This is one of the parts that work around Chromium incorrectly implementing postMessage:
-// https://bugs.chromium.org/p/chromium/issues/detail?id=1075645
-//
-// rayon::ThreadPoolBuilder (used below) executes spawn handler to populate the worker pool,
-// and then blocks the current thread until each worker unblocks its (opaque) lock.
-//
-// Normally, we could use postMessage directly inside the spawn handler to
-// post module + memory + threadPtr to each worker, and the block the current thread.
-//
-// However, that bug means that postMessage is currently delayed until the next event loop,
-// which will never spin since we block the current thread, and so the other workers will
-// never be able to unblock us.
-//
-// To work around this problem, we:
-// 1) Expose `worker_initializer` that returns module + memory pair (without threadPtr)
-//    that workers can be initialised with to become native threads.
-//    JavaScript can postMessage this pair in advance, and asynchronously wait for workers
-//    to acknowledge the receipt.
-// 2) Create a global communication channel on the Rust side using crossbeam.
-//    It will be used to send threadPtr to the pre-initialised workers
-//    instead of postMessage.
-// 3) Provide a separate `start_main_thread` that expects all workers to be ready,
-//    and just uses the provided channel to send `threadPtr`s using the
-//    shared memory and blocks the current thread until they're all grabbed.
-// 4) Provide a `worker_initializer` that is expected to be invoked from various workers,
-//    reads one `threadPtr` from the shared channel and starts running it.
-static CHANNEL: OnceCell<(Sender<rayon::ThreadBuilder>, Receiver<rayon::ThreadBuilder>)> =
-    OnceCell::new();
-
-#[wasm_bindgen]
-pub fn worker_initializer(num: usize) -> JsValue {
-    CHANNEL.get_or_init(|| bounded(num));
-    array_of_2(wasm_bindgen::module(), wasm_bindgen::memory())
-}
-
-#[wasm_bindgen]
-pub fn start_main_thread() {
-    let (sender, _) = CHANNEL.get().unwrap();
-
-    rayon::ThreadPoolBuilder::new()
-        .num_threads(sender.capacity().unwrap())
-        .spawn_handler(|thread| Ok(sender.send(thread).unwrap_throw()))
-        .build_global()
-        .unwrap_throw()
-}
-
-#[wasm_bindgen]
-pub fn start_worker_thread() {
-    let (_, receiver) = CHANNEL.get().unwrap();
-    receiver.recv().unwrap_throw().run()
-}