1 files changed, 253 insertions, 0 deletions
diff --git a/extensions/web/13_message_port.js b/extensions/web/13_message_port.js
new file mode 100644
index 000000000..50d3f5d04
--- /dev/null
+++ b/extensions/web/13_message_port.js
@@ -0,0 +1,253 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+// @ts-check
+/// <reference path="../../core/lib.deno_core.d.ts" />
+/// <reference path="../webidl/internal.d.ts" />
+/// <reference path="./internal.d.ts" />
+/// <reference path="./lib.deno_web.d.ts" />
+
+"use strict";
+
+((window) => {
+  const core = window.Deno.core;
+  const webidl = window.__bootstrap.webidl;
+  const { setEventTargetData } = window.__bootstrap.eventTarget;
+  const { defineEventHandler } = window.__bootstrap.event;
+
+  class MessageChannel {
+    /** @type {MessagePort} */
+    #port1;
+    /** @type {MessagePort} */
+    #port2;
+
+    constructor() {
+      this[webidl.brand] = webidl.brand;
+      const [port1Id, port2Id] = opCreateEntangledMessagePort();
+      const port1 = createMessagePort(port1Id);
+      const port2 = createMessagePort(port2Id);
+      this.#port1 = port1;
+      this.#port2 = port2;
+    }
+
+    get port1() {
+      webidl.assertBranded(this, MessageChannel);
+      return this.#port1;
+    }
+
+    get port2() {
+      webidl.assertBranded(this, MessageChannel);
+      return this.#port2;
+    }
+
+    [Symbol.for("Deno.inspect")](inspect) {
+      return `MessageChannel ${
+        inspect({ port1: this.port1, port2: this.port2 })
+      }`;
+    }
+
+    get [Symbol.toStringTag]() {
+      return "MessageChannel";
+    }
+  }
+
+  webidl.configurePrototype(MessageChannel);
+
+  const _id = Symbol("id");
+  const _enabled = Symbol("enabled");
+
+  /**
+   * @param {number} id
+   * @returns {MessagePort}
+   */
+  function createMessagePort(id) {
+    const port = webidl.createBranded(MessagePort);
+    setEventTargetData(port);
+    port[_id] = id;
+    return port;
+  }
+
+  class MessagePort extends EventTarget {
+    /** @type {number | null} */
+    [_id] = null;
+    /** @type {boolean} */
+    [_enabled] = false;
+
+    constructor() {
+      super();
+      webidl.illegalConstructor();
+    }
+
+    /**
+     * @param {any} message
+     * @param {object[] | PostMessageOptions} transferOrOptions
+     */
+    postMessage(message, transferOrOptions = {}) {
+      webidl.assertBranded(this, MessagePort);
+      const prefix = "Failed to execute 'postMessage' on 'MessagePort'";
+      webidl.requiredArguments(arguments.length, 1, { prefix });
+      message = webidl.converters.any(message);
+      let options;
+      if (
+        webidl.type(transferOrOptions) === "Object" &&
+        transferOrOptions !== undefined &&
+        transferOrOptions[Symbol.iterator] !== undefined
+      ) {
+        const transfer = webidl.converters["sequence<object>"](
+          transferOrOptions,
+          { prefix, context: "Argument 2" },
+        );
+        options = { transfer };
+      } else {
+        options = webidl.converters.PostMessageOptions(transferOrOptions, {
+          prefix,
+          context: "Argument 2",
+        });
+      }
+      const { transfer } = options;
+      if (transfer.includes(this)) {
+        throw new DOMException("Can not tranfer self", "DataCloneError");
+      }
+      const data = serializeJsMessageData(message, transfer);
+      if (this[_id] === null) return;
+      core.opSync("op_message_port_post_message", this[_id], data);
+    }
+
+    start() {
+      webidl.assertBranded(this, MessagePort);
+      if (this[_enabled]) return;
+      (async () => {
+        this[_enabled] = true;
+        while (true) {
+          if (this[_id] === null) break;
+          const data = await core.opAsync(
+            "op_message_port_recv_message",
+            this[_id],
+          );
+          if (data === null) break;
+          let message, transfer;
+          try {
+            const v = deserializeJsMessageData(data);
+            message = v[0];
+            transfer = v[1];
+          } catch (err) {
+            const event = new MessageEvent("messageerror", { data: err });
+            this.dispatchEvent(event);
+            return;
+          }
+          const event = new MessageEvent("message", {
+            data: message,
+            ports: transfer,
+          });
+          this.dispatchEvent(event);
+        }
+        this[_enabled] = false;
+      })();
+    }
+
+    close() {
+      webidl.assertBranded(this, MessagePort);
+      if (this[_id] !== null) {
+        core.close(this[_id]);
+        this[_id] = null;
+      }
+    }
+  }
+
+  defineEventHandler(MessagePort.prototype, "message", function (self) {
+    self.start();
+  });
+  defineEventHandler(MessagePort.prototype, "messageerror");
+
+  webidl.configurePrototype(MessagePort);
+
+  /**
+   * @returns {[number, number]}
+   */
+  function opCreateEntangledMessagePort() {
+    return core.opSync("op_message_port_create_entangled");
+  }
+
+  /**
+   * @param {globalThis.__bootstrap.messagePort.MessageData} messageData
+   * @returns {[any, object[]]}
+   */
+  function deserializeJsMessageData(messageData) {
+    /** @type {object[]} */
+    const transferables = [];
+
+    for (const transferable of messageData.transferables) {
+      switch (transferable.kind) {
+        case "messagePort": {
+          const port = createMessagePort(transferable.data);
+          transferables.push(port);
+          break;
+        }
+        default:
+          throw new TypeError("Unreachable");
+      }
+    }
+
+    const data = core.deserialize(messageData.data);
+
+    return [data, transferables];
+  }
+
+  /**
+   * @param {any} data
+   * @param {object[]} tranferables
+   * @returns {globalThis.__bootstrap.messagePort.MessageData}
+   */
+  function serializeJsMessageData(data, tranferables) {
+    let serializedData;
+    try {
+      serializedData = core.serialize(data);
+    } catch (err) {
+      throw new DOMException(err.message, "DataCloneError");
+    }
+
+    /** @type {globalThis.__bootstrap.messagePort.Transferable[]} */
+    const serializedTransferables = [];
+
+    for (const transferable of tranferables) {
+      if (transferable instanceof MessagePort) {
+        webidl.assertBranded(transferable, MessagePort);
+        const id = transferable[_id];
+        if (id === null) {
+          throw new DOMException(
+            "Can not transfer disentangled message port",
+            "DataCloneError",
+          );
+        }
+        transferable[_id] = null;
+        serializedTransferables.push({ kind: "messagePort", data: id });
+      } else {
+        throw new DOMException("Value not transferable", "DataCloneError");
+      }
+    }
+
+    return {
+      data: serializedData,
+      transferables: serializedTransferables,
+    };
+  }
+
+  webidl.converters.PostMessageOptions = webidl.createDictionaryConverter(
+    "PostMessageOptions",
+    [
+      {
+        key: "transfer",
+        converter: webidl.converters["sequence<object>"],
+        get defaultValue() {
+          return [];
+        },
+      },
+    ],
+  );
+
+  window.__bootstrap.messagePort = {
+    MessageChannel,
+    MessagePort,
+    deserializeJsMessageData,
+    serializeJsMessageData,
+  };
+})(globalThis);