michael@0: /* -*- Mode: JavaScript; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0:  */
michael@0: 
michael@0: /*
michael@0:  * This is an implementation of a "Shared Worker" using a remote browser
michael@0:  * in the hidden DOM window.  This is the implementation that lives in the
michael@0:  * "chrome process".  See FrameWorkerContent for code that lives in the
michael@0:  * "content" process and which sets up a sandbox for the worker.
michael@0:  */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
michael@0: 
michael@0: Cu.import("resource://gre/modules/Services.jsm");
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: Cu.import("resource://gre/modules/MessagePortBase.jsm");
michael@0: Cu.import("resource://gre/modules/Promise.jsm");
michael@0: 
michael@0: XPCOMUtils.defineLazyModuleGetter(this, "SocialService",
michael@0:   "resource://gre/modules/SocialService.jsm");
michael@0: 
michael@0: const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
michael@0: const HTML_NS = "http://www.w3.org/1999/xhtml";
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ["getFrameWorkerHandle"];
michael@0: 
michael@0: var workerCache = {}; // keyed by URL.
michael@0: var _nextPortId = 1;
michael@0: 
michael@0: // Retrieves a reference to a WorkerHandle associated with a FrameWorker and a
michael@0: // new ClientPort.
michael@0: this.getFrameWorkerHandle =
michael@0:  function getFrameWorkerHandle(url, clientWindow, name, origin, exposeLocalStorage = false) {
michael@0:   // prevent data/about urls - see bug 891516
michael@0:   if (['http', 'https'].indexOf(Services.io.newURI(url, null, null).scheme) < 0)
michael@0:     throw new Error("getFrameWorkerHandle requires http/https urls");
michael@0: 
michael@0:   // See if we already have a worker with this URL.
michael@0:   let existingWorker = workerCache[url];
michael@0:   if (!existingWorker) {
michael@0:     // create a remote browser and _Worker object - this will message the
michael@0:     // remote browser to do the content side of things.
michael@0:     let browserPromise = makeRemoteBrowser();
michael@0:     let options = { url: url, name: name, origin: origin,
michael@0:                     exposeLocalStorage: exposeLocalStorage };
michael@0: 
michael@0:     existingWorker = workerCache[url] = new _Worker(browserPromise, options);
michael@0:   }
michael@0: 
michael@0:   // message the content so it can establish a new connection with the worker.
michael@0:   let portid = _nextPortId++;
michael@0:   existingWorker.browserPromise.then(browser => {
michael@0:     browser.messageManager.sendAsyncMessage("frameworker:connect",
michael@0:                                             { portId: portid });
michael@0:   });
michael@0:   // return the pseudo worker object.
michael@0:   let port = new ParentPort(portid, existingWorker.browserPromise, clientWindow);
michael@0:   existingWorker.ports.set(portid, port);
michael@0:   return new WorkerHandle(port, existingWorker);
michael@0: };
michael@0: 
michael@0: // A "_Worker" is an internal representation of a worker.  It's never returned
michael@0: // directly to consumers.
michael@0: function _Worker(browserPromise, options) {
michael@0:   this.browserPromise = browserPromise;
michael@0:   this.options = options;
michael@0:   this.ports = new Map();
michael@0:   browserPromise.then(browser => {
michael@0:     browser.addEventListener("oop-browser-crashed", () => {
michael@0:       Cu.reportError("FrameWorker remote process crashed");
michael@0:       notifyWorkerError(options.origin);
michael@0:     });
michael@0: 
michael@0:     let mm = browser.messageManager;
michael@0:     // execute the content script and send the message to bootstrap the content
michael@0:     // side of the world.
michael@0:     mm.loadFrameScript("resource://gre/modules/FrameWorkerContent.js", true);
michael@0:     mm.sendAsyncMessage("frameworker:init", this.options);
michael@0:     mm.addMessageListener("frameworker:port-message", this);
michael@0:     mm.addMessageListener("frameworker:notify-worker-error", this);
michael@0:   });
michael@0: }
michael@0: 
michael@0: _Worker.prototype = {
michael@0:   // Message handler.
michael@0:   receiveMessage: function(msg) {
michael@0:     switch (msg.name) {
michael@0:       case "frameworker:port-message":
michael@0:         let port = this.ports.get(msg.data.portId);
michael@0:         port._onmessage(msg.data.data);
michael@0:         break;
michael@0:       case "frameworker:notify-worker-error":
michael@0:         notifyWorkerError(msg.data.origin);
michael@0:         break;
michael@0:     }
michael@0:   }
michael@0: }
michael@0: 
michael@0: // This WorkerHandle is exposed to consumers - it has the new port instance
michael@0: // the consumer uses to communicate with the worker.
michael@0: // public methods/properties on WorkerHandle should conform to the SharedWorker
michael@0: // api - currently that's just .port and .terminate()
michael@0: function WorkerHandle(port, worker) {
michael@0:   this.port = port;
michael@0:   this._worker = worker;
michael@0: }
michael@0: 
michael@0: WorkerHandle.prototype = {
michael@0:   // A method to terminate the worker.  The worker spec doesn't define a
michael@0:   // callback to be made in the worker when this happens, so we just kill the
michael@0:   // browser element.
michael@0:   terminate: function terminate() {
michael@0:     let url = this._worker.options.url;
michael@0:     if (!(url in workerCache)) {
michael@0:       // terminating an already terminated worker - ignore it
michael@0:       return;
michael@0:     }
michael@0:     delete workerCache[url];
michael@0:     // close all the ports we have handed out.
michael@0:     for (let [portid, port] of this._worker.ports) {
michael@0:       port.close();
michael@0:     }
michael@0:     this._worker.ports.clear();
michael@0:     this._worker.ports = null;
michael@0:     this._worker.browserPromise.then(browser => {
michael@0:       let iframe = browser.ownerDocument.defaultView.frameElement;
michael@0:       iframe.parentNode.removeChild(iframe);
michael@0:     });
michael@0:     // wipe things out just incase other reference have snuck out somehow...
michael@0:     this._worker.browserPromise = null;
michael@0:     this._worker = null;
michael@0:   }
michael@0: };
michael@0: 
michael@0: // The port that lives in the parent chrome process.  The other end of this
michael@0: // port is the "client" port in the content process, which itself is just a
michael@0: // shim which shuttles messages to/from the worker itself.
michael@0: function ParentPort(portid, browserPromise, clientWindow) {
michael@0:   this._clientWindow = clientWindow;
michael@0:   this._browserPromise = browserPromise;
michael@0:   AbstractPort.call(this, portid);
michael@0: }
michael@0: 
michael@0: ParentPort.prototype = {
michael@0:   __exposedProps__: {
michael@0:     onmessage: "rw",
michael@0:     postMessage: "r",
michael@0:     close: "r",
michael@0:     toString: "r"
michael@0:   },
michael@0:   __proto__: AbstractPort.prototype,
michael@0:   _portType: "parent",
michael@0: 
michael@0:   _dopost: function(data) {
michael@0:     this._browserPromise.then(browser => {
michael@0:       browser.messageManager.sendAsyncMessage("frameworker:port-message", data);
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   _onerror: function(err) {
michael@0:     Cu.reportError("FrameWorker: Port " + this + " handler failed: " + err + "\n" + err.stack);
michael@0:   },
michael@0: 
michael@0:   _JSONParse: function(data) {
michael@0:     if (this._clientWindow) {
michael@0:       return XPCNativeWrapper.unwrap(this._clientWindow).JSON.parse(data);
michael@0:     }
michael@0:     return JSON.parse(data);
michael@0:   },
michael@0: 
michael@0:   close: function() {
michael@0:     if (this._closed) {
michael@0:       return; // already closed.
michael@0:     }
michael@0:     // a leaky abstraction due to the worker spec not specifying how the
michael@0:     // other end of a port knows it is closing.
michael@0:     this.postMessage({topic: "social.port-closing"});
michael@0:     AbstractPort.prototype.close.call(this);
michael@0:     this._clientWindow = null;
michael@0:     // this._pendingMessagesOutgoing should still be drained, as a closed
michael@0:     // port will still get "entangled" quickly enough to deliver the messages.
michael@0:   }
michael@0: }
michael@0: 
michael@0: // Make the <browser remote="true"> element that hosts the worker.
michael@0: function makeRemoteBrowser() {
michael@0:   let deferred = Promise.defer();
michael@0:   let hiddenDoc = Services.appShell.hiddenDOMWindow.document;
michael@0:   // Create a HTML iframe with a chrome URL, then this can host the browser.
michael@0:   let iframe = hiddenDoc.createElementNS(HTML_NS, "iframe");
michael@0:   iframe.setAttribute("src", "chrome://global/content/mozilla.xhtml");
michael@0:   iframe.addEventListener("load", function onLoad() {
michael@0:     iframe.removeEventListener("load", onLoad, true);
michael@0:     let browser = iframe.contentDocument.createElementNS(XUL_NS, "browser");
michael@0:     browser.setAttribute("type", "content");
michael@0:     browser.setAttribute("disableglobalhistory", "true");
michael@0:     browser.setAttribute("remote", "true");
michael@0: 
michael@0:     iframe.contentDocument.documentElement.appendChild(browser);
michael@0:     deferred.resolve(browser);
michael@0:   }, true);
michael@0:   hiddenDoc.documentElement.appendChild(iframe);
michael@0:   return deferred.promise;
michael@0: }
michael@0: 
michael@0: function notifyWorkerError(origin) {
michael@0:   // Try to retrieve the worker's associated provider, if it has one, to set its
michael@0:   // error state.
michael@0:   SocialService.getProvider(origin, function (provider) {
michael@0:     if (provider)
michael@0:       provider.errorState = "frameworker-error";
michael@0:     Services.obs.notifyObservers(null, "social:frameworker-error", origin);
michael@0:   });
michael@0: }