1 files changed, 158 insertions, 0 deletions
diff --git a/toolkit/jetpack/sdk/content/worker-child.js b/toolkit/jetpack/sdk/content/worker-child.js
new file mode 100644
index 000000000..dbf65a933
--- /dev/null
+++ b/toolkit/jetpack/sdk/content/worker-child.js
@@ -0,0 +1,158 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+'use strict';
+
+const { merge } = require('../util/object');
+const { Class } = require('../core/heritage');
+const { emit } = require('../event/core');
+const { EventTarget } = require('../event/target');
+const { getInnerId, getByInnerId } = require('../window/utils');
+const { instanceOf, isObject } = require('../lang/type');
+const system = require('../system/events');
+const { when } = require('../system/unload');
+const { WorkerSandbox } = require('./sandbox');
+const { Ci } = require('chrome');
+const { process, frames } = require('../remote/child');
+
+const EVENTS = {
+  'chrome-page-shown': 'pageshow',
+  'content-page-shown': 'pageshow',
+  'chrome-page-hidden': 'pagehide',
+  'content-page-hidden': 'pagehide',
+  'inner-window-destroyed': 'detach',
+}
+
+// The parent Worker must have been created (or an async message sent to spawn
+// its creation) before creating the WorkerChild or messages from the content
+// script to the parent will get lost.
+const WorkerChild = Class({
+  implements: [EventTarget],
+
+  initialize(options) {
+    merge(this, options);
+    keepAlive.set(this.id, this);
+
+    this.windowId = getInnerId(this.window);
+    if (this.contentScriptOptions)
+      this.contentScriptOptions = JSON.parse(this.contentScriptOptions);
+
+    this.port = EventTarget();
+    this.port.on('*', this.send.bind(this, 'event'));
+    this.on('*', this.send.bind(this));
+
+    this.observe = this.observe.bind(this);
+
+    for (let topic in EVENTS)
+      system.on(topic, this.observe);
+
+    this.receive = this.receive.bind(this);
+    process.port.on('sdk/worker/message', this.receive);
+
+    this.sandbox = WorkerSandbox(this, this.window);
+
+    // If the document has an unexpected readyState, its worker-child instance is initialized
+    // as frozen until one of the known readyState is reached.
+    let initialDocumentReadyState = this.window.document.readyState;
+    this.frozen = [
+      "loading", "interactive", "complete"
+    ].includes(initialDocumentReadyState) ? false : true;
+
+    if (this.frozen) {
+      console.warn("SDK worker-child started as frozen on unexpected initial document.readyState", {
+        initialDocumentReadyState, windowLocation: this.window.location.href,
+      });
+    }
+
+    this.frozenMessages = [];
+    this.on('pageshow', () => {
+      this.frozen = false;
+      this.frozenMessages.forEach(args => this.sandbox.emit(...args));
+      this.frozenMessages = [];
+    });
+    this.on('pagehide', () => {
+      this.frozen = true;
+    });
+  },
+
+  // messages
+  receive(process, id, args) {
+    if (id !== this.id)
+      return;
+    args = JSON.parse(args);
+
+    if (this.frozen)
+      this.frozenMessages.push(args);
+    else
+      this.sandbox.emit(...args);
+
+    if (args[0] === 'detach')
+      this.destroy(args[1]);
+  },
+
+  send(...args) {
+    process.port.emit('sdk/worker/event', this.id, JSON.stringify(args, exceptions));
+  },
+
+  // notifications
+  observe({ type, subject }) {
+    if (!this.sandbox)
+      return;
+
+    if (subject.defaultView && getInnerId(subject.defaultView) === this.windowId) {
+      this.sandbox.emitSync(EVENTS[type]);
+      emit(this, EVENTS[type]);
+    }
+
+    if (type === 'inner-window-destroyed' &&
+        subject.QueryInterface(Ci.nsISupportsPRUint64).data === this.windowId) {
+      this.destroy();
+    }
+  },
+
+  get frame() {
+    return frames.getFrameForWindow(this.window.top);
+  },
+
+  // detach/destroy: unload and release the sandbox
+  destroy(reason) {
+    if (!this.sandbox)
+      return;
+
+    for (let topic in EVENTS)
+      system.off(topic, this.observe);
+    process.port.off('sdk/worker/message', this.receive);
+
+    this.sandbox.destroy(reason);
+    this.sandbox = null;
+    keepAlive.delete(this.id);
+
+    this.send('detach');
+  }
+})
+exports.WorkerChild = WorkerChild;
+
+// Error instances JSON poorly
+function exceptions(key, value) {
+  if (!isObject(value) || !instanceOf(value, Error))
+    return value;
+  let _errorType = value.constructor.name;
+  let { message, fileName, lineNumber, stack, name } = value;
+  return { _errorType, message, fileName, lineNumber, stack, name };
+}
+
+// workers for windows in this tab
+var keepAlive = new Map();
+
+process.port.on('sdk/worker/create', (process, options, cpows) => {
+  options.window = cpows.window;
+  let worker = new WorkerChild(options);
+
+  let frame = frames.getFrameForWindow(options.window.top);
+  frame.port.emit('sdk/worker/connect', options.id, options.window.location.href);
+});
+
+when(reason => {
+  for (let worker of keepAlive.values())
+    worker.destroy(reason);
+});