feat(extensions): add BroadcastChannel

Co-Authored-By: Ben Noordhuis <[email protected]>
Fixes: #10354

Cargo.toml

@@ -16,6 +16,7 @@ members = [
   "extensions/webgpu",
   "extensions/webidl",
   "extensions/websocket",
+  "extensions/broadcast_channel",
 ]
 exclude = [
   "std/hash/_wasm"

cli/build.rs

@@ -8,6 +8,7 @@ use deno_core::serde_json::json;
 use deno_core::serde_json::Value;
 use deno_core::JsRuntime;
 use deno_core::RuntimeOptions;
+use deno_runtime::deno_broadcast_channel;
 use deno_runtime::deno_console;
 use deno_runtime::deno_crypto;
 use deno_runtime::deno_fetch;
@@ -74,6 +75,10 @@ fn create_compiler_snapshot(
   op_crate_libs.insert("deno.websocket", deno_websocket::get_declaration());
   op_crate_libs.insert("deno.webstorage", deno_webstorage::get_declaration());
   op_crate_libs.insert("deno.crypto", deno_crypto::get_declaration());
+  op_crate_libs.insert(
+    "deno.broadcast_channel",
+    deno_broadcast_channel::get_declaration(),
+  );
 
   // ensure we invalidate the build properly.
   for (_, path) in op_crate_libs.iter() {
@@ -300,6 +305,10 @@ fn main() {
     "cargo:rustc-env=DENO_CRYPTO_LIB_PATH={}",
     deno_crypto::get_declaration().display()
   );
+  println!(
+    "cargo:rustc-env=DENO_BROADCAST_CHANNEL_LIB_PATH={}",
+    deno_broadcast_channel::get_declaration().display()
+  );
 
   println!("cargo:rustc-env=TARGET={}", env::var("TARGET").unwrap());
   println!("cargo:rustc-env=PROFILE={}", env::var("PROFILE").unwrap());

cli/main.rs

@@ -302,7 +302,7 @@ fn print_cache_info(
 
 pub fn get_types(unstable: bool) -> String {
   let mut types = format!(
-    "{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}",
+    "{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}",
     crate::tsc::DENO_NS_LIB,
     crate::tsc::DENO_CONSOLE_LIB,
     crate::tsc::DENO_URL_LIB,
@@ -313,6 +313,7 @@ pub fn get_types(unstable: bool) -> String {
     crate::tsc::DENO_WEBSOCKET_LIB,
     crate::tsc::DENO_WEBSTORAGE_LIB,
     crate::tsc::DENO_CRYPTO_LIB,
+    crate::tsc::DENO_BROADCAST_CHANNEL_LIB,
     crate::tsc::SHARED_GLOBALS_LIB,
     crate::tsc::WINDOW_LIB,
   );

cli/tsc.rs

@@ -41,6 +41,8 @@ pub static DENO_WEBSOCKET_LIB: &str =
 pub static DENO_WEBSTORAGE_LIB: &str =
   include_str!(env!("DENO_WEBSTORAGE_LIB_PATH"));
 pub static DENO_CRYPTO_LIB: &str = include_str!(env!("DENO_CRYPTO_LIB_PATH"));
+pub static DENO_BROADCAST_CHANNEL_LIB: &str =
+  include_str!(env!("DENO_BROADCAST_CHANNEL_LIB_PATH"));
 pub static SHARED_GLOBALS_LIB: &str =
   include_str!("dts/lib.deno.shared_globals.d.ts");
 pub static WINDOW_LIB: &str = include_str!("dts/lib.deno.window.d.ts");

extensions/broadcast_channel/01_broadcast_channel.js

@@ -0,0 +1,117 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+"use strict";
+
+((window) => {
+  const core = window.Deno.core;
+  const webidl = window.__bootstrap.webidl;
+
+  const handlerSymbol = Symbol("eventHandlers");
+  function makeWrappedHandler(handler) {
+    function wrappedHandler(...args) {
+      if (typeof wrappedHandler.handler !== "function") {
+        return;
+      }
+      return wrappedHandler.handler.call(this, ...args);
+    }
+    wrappedHandler.handler = handler;
+    return wrappedHandler;
+  }
+  // TODO(lucacasonato) reuse when we can reuse code between web crates
+  function defineEventHandler(emitter, name) {
+    // HTML specification section 8.1.5.1
+    Object.defineProperty(emitter, `on${name}`, {
+      get() {
+        return this[handlerSymbol]?.get(name)?.handler;
+      },
+      set(value) {
+        if (!this[handlerSymbol]) {
+          this[handlerSymbol] = new Map();
+        }
+        let handlerWrapper = this[handlerSymbol]?.get(name);
+        if (handlerWrapper) {
+          handlerWrapper.handler = value;
+        } else {
+          handlerWrapper = makeWrappedHandler(value);
+          this.addEventListener(name, handlerWrapper);
+        }
+        this[handlerSymbol].set(name, handlerWrapper);
+      },
+      configurable: true,
+      enumerable: true,
+    });
+  }
+
+  const _name = Symbol("[[name]]");
+  const _closed = Symbol("[[closed]]");
+  const _rid = Symbol("[[rid]]");
+
+  class BroadcastChannel extends EventTarget {
+    [_name];
+    [_closed] = false;
+    [_rid];
+
+    get name() {
+      return this[_name];
+    }
+
+    constructor(name) {
+      super();
+
+      window.location;
+
+      const prefix = "Failed to construct 'broadcastChannel'";
+      webidl.requiredArguments(arguments.length, 1, { prefix });
+
+      this[_name] = webidl.converters["DOMString"](name, {
+        prefix,
+        context: "Argument 1",
+      });
+
+      this[_rid] = core.opSync("op_broadcast_open", this[_name]);
+
+      this[webidl.brand] = webidl.brand;
+
+      this.#eventLoop();
+    }
+
+    postMessage(message) {
+      webidl.assertBranded(this, BroadcastChannel);
+
+      if (this[_closed]) {
+        throw new DOMException("Already closed", "InvalidStateError");
+      }
+
+      core.opAsync("op_broadcast_send", this[_rid], core.serialize(message));
+    }
+
+    close() {
+      webidl.assertBranded(this, BroadcastChannel);
+
+      this[_closed] = true;
+      core.close(this[_rid]);
+    }
+
+    async #eventLoop() {
+      while (!this[_closed]) {
+        const message = await core.opAsync(
+          "op_broadcast_next_event",
+          this[_rid],
+        );
+
+        if (message.length !== 0) {
+          const event = new MessageEvent("message", {
+            data: core.deserialize(message),
+            origin: window.location,
+          });
+          event.target = this;
+          this.dispatchEvent(event);
+        }
+      }
+    }
+  }
+
+  defineEventHandler(BroadcastChannel.prototype, "message");
+  defineEventHandler(BroadcastChannel.prototype, "messageerror");
+
+  window.__bootstrap.broadcastChannel = { BroadcastChannel };
+})(this);

extensions/broadcast_channel/Cargo.toml

@@ -0,0 +1,18 @@
+# Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+[package]
+name = "deno_broadcast_channel"
+version = "0.1.0"
+edition = "2018"
+description = "Implementation of BroadcastChannel API for Deno"
+authors = ["the Deno authors"]
+license = "MIT"
+readme = "README.md"
+repository = "https://github.com/denoland/deno"
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+deno_core = { version = "0.87.0", path = "../../core" }
+tokio = { version = "1.4.0", features = ["full"] }

extensions/broadcast_channel/README.md

@@ -0,0 +1,5 @@
+# deno_broadcast_channel
+
+This crate implements the BroadcastChannel functions of Deno.
+
+Spec: https://html.spec.whatwg.org/multipage/web-messaging.html

extensions/broadcast_channel/lib.deno_broadcast_channel.d.ts

@@ -0,0 +1,55 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+// deno-lint-ignore-file no-explicit-any
+
+/// <reference no-default-lib="true" />
+/// <reference lib="esnext" />
+
+interface BroadcastChannelEventMap {
+  "message": MessageEvent;
+  "messageerror": MessageEvent;
+}
+
+interface BroadcastChannel extends EventTarget {
+  /**
+   * Returns the channel name (as passed to the constructor).
+   */
+  readonly name: string;
+  onmessage: ((this: BroadcastChannel, ev: MessageEvent) => any) | null;
+  onmessageerror: ((this: BroadcastChannel, ev: MessageEvent) => any) | null;
+  /**
+   * Closes the BroadcastChannel object, opening it up to garbage collection.
+   */
+  close(): void;
+  /**
+   * Sends the given message to other BroadcastChannel objects set up for
+   * this channel. Messages can be structured objects, e.g. nested objects
+   * and arrays.
+   */
+  postMessage(message: any): void;
+  addEventListener<K extends keyof BroadcastChannelEventMap>(
+    type: K,
+    listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any,
+    options?: boolean | AddEventListenerOptions,
+  ): void;
+  addEventListener(
+    type: string,
+    listener: EventListenerOrEventListenerObject,
+    options?: boolean | AddEventListenerOptions,
+  ): void;
+  removeEventListener<K extends keyof BroadcastChannelEventMap>(
+    type: K,
+    listener: (this: BroadcastChannel, ev: BroadcastChannelEventMap[K]) => any,
+    options?: boolean | EventListenerOptions,
+  ): void;
+  removeEventListener(
+    type: string,
+    listener: EventListenerOrEventListenerObject,
+    options?: boolean | EventListenerOptions,
+  ): void;
+}
+
+declare var BroadcastChannel: {
+  prototype: BroadcastChannel;
+  new (name: string): BroadcastChannel;
+};