gecko/testing/marionette/marionette-server.js

/* 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 FRAME_SCRIPT = "chrome://marionette/content/marionette-listener.js";

// import logger
Cu.import("resource://gre/modules/services-common/log4moz.js");
let logger = Log4Moz.repository.getLogger("Marionette");
logger.info('marionette-server.js loaded');

let loader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
               .getService(Ci.mozIJSSubScriptLoader);
loader.loadSubScript("chrome://marionette/content/marionette-simpletest.js");
loader.loadSubScript("chrome://marionette/content/marionette-log-obj.js");
Cu.import("chrome://marionette/content/marionette-elements.js");
let utils = {};
loader.loadSubScript("chrome://marionette/content/EventUtils.js", utils);
loader.loadSubScript("chrome://marionette/content/ChromeUtils.js", utils);
loader.loadSubScript("chrome://marionette/content/atoms.js", utils);

let specialpowers = {};
loader.loadSubScript("chrome://specialpowers/content/SpecialPowersObserver.js",
                     specialpowers);
specialpowers.specialPowersObserver = new specialpowers.SpecialPowersObserver();
specialpowers.specialPowersObserver.init();

Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/FileUtils.jsm");
Cu.import("resource://gre/modules/NetUtil.jsm");  

Services.prefs.setBoolPref("marionette.contentListener", false);
let appName = Services.appinfo.name;

// dumpn needed/used by dbg-transport.js
this.dumpn = function dumpn(str) {
  logger.trace(str);
}
loader.loadSubScript("resource://gre/modules/devtools/DevToolsUtils.js");
loader.loadSubScript("resource://gre/modules/devtools/server/transport.js");

let bypassOffline = false;
let qemu = "0";
let device = null;

try {
  XPCOMUtils.defineLazyGetter(this, "libcutils", function () {
    Cu.import("resource://gre/modules/systemlibs.js");
    return libcutils;
  });
  if (libcutils) {
    qemu = libcutils.property_get("ro.kernel.qemu");
    logger.info("B2G emulator: " + (qemu == "1" ? "yes" : "no"));
    device = libcutils.property_get("ro.product.device");
    logger.info("Device detected is " + device);
    bypassOffline = (qemu == "1" || device == "panda");
  }
}
catch(e) {}

if (bypassOffline) {
  logger.info("Bypassing offline status.");
  Services.prefs.setBoolPref("network.gonk.manage-offline-status", false);
  Services.io.manageOfflineStatus = false;
  Services.io.offline = false;
}

// This is used to prevent newSession from returning before the telephony
// API's are ready; see bug 792647.  This assumes that marionette-server.js
// will be loaded before the 'system-message-listener-ready' message
// is fired.  If this stops being true, this approach will have to change.
let systemMessageListenerReady = false;
Services.obs.addObserver(function() {
  systemMessageListenerReady = true;
}, "system-message-listener-ready", false);

/**
 * An object representing a frame that Marionette has loaded a
 * frame script in.
 */
function MarionetteRemoteFrame(windowId, frameId) {
  this.windowId = windowId;
  this.frameId = frameId;
  this.targetFrameId = null;
  this.messageManager = null;
  this.command_id = null;
}
// persistent list of remote frames that Marionette has loaded a frame script in
let remoteFrames = [];

/*
 * Custom exceptions
 */
function FrameSendNotInitializedError(frame) {
  this.code = 54;
  this.frame = frame;
  this.message = "Error sending message to frame (NS_ERROR_NOT_INITIALIZED)";
  this.toString = function() {
    return this.message + " " + this.frame + "; frame has closed.";
  }
}

function FrameSendFailureError(frame) {
  this.code = 55;
  this.frame = frame;
  this.message = "Error sending message to frame (NS_ERROR_FAILURE)";
  this.toString = function() {
    return this.message + " " + this.frame + "; frame not responding.";
  }
}

/**
 * The server connection is responsible for all marionette API calls. It gets created
 * for each connection and manages all chrome and browser based calls. It
 * mediates content calls by issuing appropriate messages to the content process.
 */
function MarionetteServerConnection(aPrefix, aTransport, aServer)
{
  this.uuidGen = Cc["@mozilla.org/uuid-generator;1"]
                   .getService(Ci.nsIUUIDGenerator);

  this.prefix = aPrefix;
  this.server = aServer;
  this.conn = aTransport;
  this.conn.hooks = this;

  // marionette uses a protocol based on the debugger server, which requires
  // passing back "actor ids" with responses. unlike the debugger server,
  // we don't have multiple actors, so just use a dummy value of "0" here
  this.actorID = "0";

  this.globalMessageManager = Cc["@mozilla.org/globalmessagemanager;1"]
                             .getService(Ci.nsIMessageBroadcaster);
  this.messageManager = this.globalMessageManager;
  this.browsers = {}; //holds list of BrowserObjs
  this.curBrowser = null; // points to current browser
  this.context = "content";
  this.scriptTimeout = null;
  this.searchTimeout = null;
  this.pageTimeout = null;
  this.timer = null;
  this.marionetteLog = new MarionetteLogObj();
  this.command_id = null;
  this.mainFrame = null; //topmost chrome frame
  this.curFrame = null; //subframe that currently has focus
  this.importedScripts = FileUtils.getFile('TmpD', ['marionettescriptchrome']);
  this.currentRemoteFrame = null; // a member of remoteFrames
  this.testName = null;
  this.mozBrowserClose = null;

  //register all message listeners
  this.addMessageManagerListeners(this.messageManager);
}

MarionetteServerConnection.prototype = {

  /**
   * Debugger transport callbacks:
   */
  onPacket: function MSC_onPacket(aPacket) {
    // Dispatch the request
    if (this.requestTypes && this.requestTypes[aPacket.type]) {
      try {
        this.requestTypes[aPacket.type].bind(this)(aPacket);
      } catch(e) {
        this.conn.send({ error: ("error occurred while processing '" +
                                 aPacket.type),
                        message: e });
      }
    } else {
      this.conn.send({ error: "unrecognizedPacketType",
                       message: ('Marionette does not ' +
                                 'recognize the packet type "' +
                                 aPacket.type + '"') });
    }
  },

  onClosed: function MSC_onClosed(aStatus) {
    this.server._connectionClosed(this);
    this.deleteSession();
  },

  /**
   * Helper methods:
   */

  /**
   * Switches to the global ChromeMessageBroadcaster, potentially replacing a frame-specific
   * ChromeMessageSender.  Has no effect if the global ChromeMessageBroadcaster is already
   * in use.  If this replaces a frame-specific ChromeMessageSender, it removes the message
   * listeners from that sender, and then puts the corresponding frame script "to sleep",
   * which removes most of the message listeners from it as well.
   */
  switchToGlobalMessageManager: function MDA_switchToGlobalMM() {
    if (this.currentRemoteFrame !== null) {
      this.removeMessageManagerListeners(this.messageManager);
      this.sendAsync("sleepSession", null, null, true);
    }
    this.messageManager = this.globalMessageManager;
    this.currentRemoteFrame = null;
  },

  /**
   * Helper method to send async messages to the content listener
   *
   * @param string name
   *        Suffix of the targetted message listener (Marionette:<suffix>)
   * @param object values
   *        Object to send to the listener
   */
  sendAsync: function MDA_sendAsync(name, values, commandId, ignoreFailure) {
    let success = true;
    if (values instanceof Object && commandId) {
      values.command_id = commandId;
    }
    if (this.currentRemoteFrame !== null) {
      try {
        this.messageManager.sendAsyncMessage(
          "Marionette:" + name + this.currentRemoteFrame.targetFrameId, values);
      }
      catch(e) {
        if (!ignoreFailure) {
          success = false;
          let error = e;
          switch(e.result) {
            case Components.results.NS_ERROR_FAILURE:
              error = new FrameSendFailureError(this.currentRemoteFrame);
              break;
            case Components.results.NS_ERROR_NOT_INITIALIZED:
              error = new FrameSendNotInitializedError(this.currentRemoteFrame);
              break;
            default:
              break;
          }
          let code = error.hasOwnProperty('code') ? e.code : 500;
          this.sendError(error.toString(), code, error.stack, commandId);
        }
      }
    }
    else {
      this.messageManager.broadcastAsyncMessage(
        "Marionette:" + name + this.curBrowser.curFrameId, values);
    }
    return success;
  },

  /**
   * Adds listeners for messages from content frame scripts.
   *
   * @param object messageManager
   *        The messageManager object (ChromeMessageBroadcaster or ChromeMessageSender)
   *        to which the listeners should be added.
   */
  addMessageManagerListeners: function MDA_addMessageManagerListeners(messageManager) {
    messageManager.addMessageListener("Marionette:ok", this);
    messageManager.addMessageListener("Marionette:done", this);
    messageManager.addMessageListener("Marionette:error", this);
    messageManager.addMessageListener("Marionette:log", this);
    messageManager.addMessageListener("Marionette:shareData", this);
    messageManager.addMessageListener("Marionette:register", this);
    messageManager.addMessageListener("Marionette:runEmulatorCmd", this);
    messageManager.addMessageListener("Marionette:switchToFrame", this);
  },

  /**
   * Removes listeners for messages from content frame scripts.
   *
   * @param object messageManager
   *        The messageManager object (ChromeMessageBroadcaster or ChromeMessageSender)
   *        from which the listeners should be removed.
   */
  removeMessageManagerListeners: function MDA_removeMessageManagerListeners(messageManager) {
    messageManager.removeMessageListener("Marionette:ok", this);
    messageManager.removeMessageListener("Marionette:done", this);
    messageManager.removeMessageListener("Marionette:error", this);
    messageManager.removeMessageListener("Marionette:log", this);
    messageManager.removeMessageListener("Marionette:shareData", this);
    messageManager.removeMessageListener("Marionette:register", this);
    messageManager.removeMessageListener("Marionette:runEmulatorCmd", this);
    messageManager.removeMessageListener("Marionette:switchToFrame", this);
  },

  logRequest: function MDA_logRequest(type, data) {
    logger.debug("Got request: " + type + ", data: " + JSON.stringify(data) + ", id: " + this.command_id);
  },

  /**
   * Generic method to pass a response to the client
   *
   * @param object msg
   *        Response to send back to client
   * @param string command_id
   *        Unique identifier assigned to the client's request.
   *        Used to distinguish the asynchronous responses.
   */
  sendToClient: function MDA_sendToClient(msg, command_id) {
    logger.info("sendToClient: " + JSON.stringify(msg) + ", " + command_id +
                ", " + this.command_id);
    if (!command_id) {
      logger.warn("got a response with no command_id");
      return;
    }
    else if (command_id != -1) {
      // A command_id of -1 is used for emulator callbacks, and those
      // don't use this.command_id.
      if (!this.command_id) {
        // A null value for this.command_id means we've already processed
        // a message for the previous value, and so the current message is a
        // duplicate.
        logger.warn("ignoring duplicate response for command_id " + command_id);
        return;
      }
      else if (this.command_id != command_id) {
        logger.warn("ignoring out-of-sync response");
        return;
      }
    }
    this.conn.send(msg);
    if (command_id != -1) {
      // Don't unset this.command_id if this message is to process an
      // emulator callback, since another response for this command_id is
      // expected, after the containing call to execute_async_script finishes.
      this.command_id = null;
    }
  },

  /**
   * Send a value to client
   *
   * @param object value
   *        Value to send back to client
   * @param string command_id
   *        Unique identifier assigned to the client's request.
   *        Used to distinguish the asynchronous responses.
   */
  sendResponse: function MDA_sendResponse(value, command_id) {
    if (typeof(value) == 'undefined')
        value = null;
    this.sendToClient({from:this.actorID, value: value}, command_id);
  },

  sayHello: function MDA_sayHello() {
    this.conn.send({ from: "root",
                     applicationType: "gecko",
                     traits: [] });
  },

  getMarionetteID: function MDA_getMarionette() {
    this.conn.send({ "from": "root", "id": this.actorID });
  },

  /**
   * Send ack to client
   * 
   * @param string command_id
   *        Unique identifier assigned to the client's request.
   *        Used to distinguish the asynchronous responses.
   */
  sendOk: function MDA_sendOk(command_id) {
    this.sendToClient({from:this.actorID, ok: true}, command_id);
  },

  /**
   * Send error message to client
   *
   * @param string message
   *        Error message
   * @param number status
   *        Status number
   * @param string trace
   *        Stack trace
   * @param string command_id
   *        Unique identifier assigned to the client's request.
   *        Used to distinguish the asynchronous responses.
   */
  sendError: function MDA_sendError(message, status, trace, command_id) {
    let error_msg = {message: message, status: status, stacktrace: trace};
    this.sendToClient({from:this.actorID, error: error_msg}, command_id);
  },

  /**
   * Creates an error message for a JavaScript exception thrown during
   * execute_(async_)script.
   *
   * This will generate a [msg, trace] pair like:
   *
   * ['ReferenceError: foo is not defined',
   *  'execute_script @test_foo.py, line 10
   *   inline javascript, line 2
   *   src: "return foo;"']
   *
   * @param error An Error object passed to a catch() clause.
            fnName The name of the function to use in the stack trace message
                   (e.g., 'execute_script').
            pythonFile The filename of the test file containing the Marionette
                    command that caused this exception to occur.
            pythonLine The line number of the above test file.
            script The JS script being executed in text form.
   */
  createStackMessage: function MDA_createStackMessage(error, fnName, pythonFile,
      pythonLine, script) {
    let python_stack = fnName + " @" + pythonFile + ", line " + pythonLine;
    let stack = error.stack.split("\n");
    let line = stack[0].substr(stack[0].lastIndexOf(':') + 1);
    let msg = error.name + ": " + error.message;
    let trace = python_stack +
                "\ninline javascript, line " + line +
                "\nsrc: \"" + script.split("\n")[line] + "\"";
    return [msg, trace];
  },

  /**
   * Gets the current active window
   * 
   * @return nsIDOMWindow
   */
  getCurrentWindow: function MDA_getCurrentWindow() {
    let type = null;
    if (this.curFrame == null) {
      if (this.curBrowser == null) {
        if (this.context == "content") {
          type = 'navigator:browser';
        }
        return Services.wm.getMostRecentWindow(type);
      }
      else {
        return this.curBrowser.window;
      }
    }
    else {
      return this.curFrame;
    }
  },

  /**
   * Gets the the window enumerator
   *
   * @return nsISimpleEnumerator
   */
  getWinEnumerator: function MDA_getWinEnumerator() {
    let type = null;
    if (appName != "B2G" && this.context == "content") {
      type = 'navigator:browser';
    }
    return Services.wm.getEnumerator(type);
  },

  /**
   * Create a new BrowserObj for window and add to known browsers
   * 
   * @param nsIDOMWindow win
   *        Window for which we will create a BrowserObj
   *
   * @return string
   *        Returns the unique server-assigned ID of the window
   */
  addBrowser: function MDA_addBrowser(win) {
    let browser = new BrowserObj(win);
    let winId = win.QueryInterface(Ci.nsIInterfaceRequestor).
                    getInterface(Ci.nsIDOMWindowUtils).outerWindowID;
    winId = winId + ((appName == "B2G") ? '-b2g' : '');
    this.browsers[winId] = browser;
    this.curBrowser = this.browsers[winId];
    if (this.curBrowser.elementManager.seenItems[winId] == undefined) {
      //add this to seenItems so we can guarantee the user will get winId as this window's id
      this.curBrowser.elementManager.seenItems[winId] = Cu.getWeakReference(win);
    }
  },

  /**
   * Start a new session in a new browser. 
   *
   * If newSession is true, we will switch focus to the start frame 
   * when it registers. Also, if it is in desktop, then a new tab 
   * with the start page uri (about:blank) will be opened.
   *
   * @param nsIDOMWindow win
   *        Window whose browser we need to access
   * @param boolean newSession
   *        True if this is the first time we're talking to this browser
   */
  startBrowser: function MDA_startBrowser(win, newSession) {
    this.mainFrame = win;
    this.curFrame = null;
    this.addBrowser(win);
    this.curBrowser.newSession = newSession;
    this.curBrowser.startSession(newSession, win, this.whenBrowserStarted.bind(this));
  },

  /**
   * Callback invoked after a new session has been started in a browser.
   * Loads the Marionette frame script into the browser if needed.
   *
   * @param nsIDOMWindow win
   *        Window whose browser we need to access
   * @param boolean newSession
   *        True if this is the first time we're talking to this browser
   */
  whenBrowserStarted: function MDA_whenBrowserStarted(win, newSession) {
    try {
      if (!Services.prefs.getBoolPref("marionette.contentListener") || !newSession) {
        this.curBrowser.loadFrameScript(FRAME_SCRIPT, win);
      }
    }
    catch (e) {
      //there may not always be a content process
      logger.info("could not load listener into content for page: " + win.location.href);
    }
    utils.window = win;
  },

  /**
   * Recursively get all labeled text
   *
   * @param nsIDOMElement el
   *        The parent element
   * @param array lines
   *        Array that holds the text lines
   */
  getVisibleText: function MDA_getVisibleText(el, lines) {
    let nodeName = el.nodeName;
    try {
      if (utils.isElementDisplayed(el)) {
        if (el.value) {
          lines.push(el.value);
        }
        for (var child in el.childNodes) {
          this.getVisibleText(el.childNodes[child], lines);
        };
      }
    }
    catch (e) {
      if (nodeName == "#text") {
        lines.push(el.textContent);
      }
    }
  },

  getCommandId: function MDA_getCommandId() {
    return this.uuidGen.generateUUID().toString();
  },

  /**
   * Marionette API:
   *
   * All methods implementing a command from the client should create a
   * command_id, and then use this command_id in all messages exchanged with
   * the frame scripts and with responses sent to the client.  This prevents
   * commands and responses from getting out-of-sync, which can happen in
   * the case of execute_async calls that timeout and then later send a
   * response, and other situations.  See bug 779011. See setScriptTimeout()
   * for a basic example.
   */

  /**
   * Create a new session. This creates a BrowserObj.
   *
   * In a desktop environment, this opens a new 'about:blank' tab for 
   * the client to test in.
   *
   */
  newSession: function MDA_newSession() {
    this.command_id = this.getCommandId();
    this.newSessionCommandId = this.command_id;

    this.scriptTimeout = 10000;

    function waitForWindow() {
      let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
      let win = this.getCurrentWindow();
      if (!win ||
          (appName == "Firefox" && !win.gBrowser) ||
          (appName == "Fennec" && !win.BrowserApp)) { 
        checkTimer.initWithCallback(waitForWindow.bind(this), 100, Ci.nsITimer.TYPE_ONE_SHOT);
      }
      else {
        this.startBrowser(win, true);
      }
    }

    this.switchToGlobalMessageManager();

    if (!Services.prefs.getBoolPref("marionette.contentListener")) {
      waitForWindow.call(this);
    }
    else if ((appName != "Firefox") && (this.curBrowser == null)) {
      //if there is a content listener, then we just wake it up
      this.addBrowser(this.getCurrentWindow());
      this.curBrowser.startSession(false, this.getCurrentWindow(), this.whenBrowserStarted);
      this.messageManager.broadcastAsyncMessage("Marionette:restart", {});
    }
    else {
      this.sendError("Session already running", 500, null, this.command_id);
    }
  },

  getSessionCapabilities: function MDA_getSessionCapabilities(){
    this.command_id = this.getCommandId();

    let rotatable = appName == "B2G" ? true : false;

    let value = {
          'appBuildId' : Services.appinfo.appBuildID,
          'XULappId' : Services.appinfo.ID,
          'cssSelectorsEnabled': true,
          'browserName': appName,
          'handlesAlerts': false,
          'javascriptEnabled': true,
          'nativeEvents': false,
          'platform': Services.appinfo.OS,
          'device': qemu == "1" ? "qemu" : (!device ? "desktop" : device),
          'rotatable': rotatable,
          'takesScreenshot': false,
          'version': Services.appinfo.version
    };

    this.sendResponse(value, this.command_id);
  },

  getStatus: function MDA_getStatus(){
    this.command_id = this.getCommandId();

    let arch;
    try {
      arch = (Services.appinfo.XPCOMABI || 'unknown').split('-')[0]
    }
    catch (ignored) {
      arch = 'unknown'
    };

    let value = {
          'os': {
            'arch': arch,
            'name': Services.appinfo.OS,
            'version': 'unknown'
          },
          'build': {
            'revision': 'unknown',
            'time': Services.appinfo.platformBuildID,
            'version': Services.appinfo.version
          }
    };

    this.sendResponse(value, this.command_id);
  },

  /**
   * Log message. Accepts user defined log-level.
   *
   * @param object aRequest
   *        'value' member holds log message
   *        'level' member hold log level
   */
  log: function MDA_log(aRequest) {
    this.command_id = this.getCommandId();
    this.marionetteLog.log(aRequest.value, aRequest.level);
    this.sendOk(this.command_id);
  },

  /**
   * Return all logged messages.
   */
  getLogs: function MDA_getLogs() {
    this.command_id = this.getCommandId();
    this.sendResponse(this.marionetteLog.getLogs(), this.command_id);
  },

  /**
   * Sets the context of the subsequent commands to be either 'chrome' or 'content'
   *
   * @param object aRequest
   *        'value' member holds the name of the context to be switched to
   */
  setContext: function MDA_setContext(aRequest) {
    this.command_id = this.getCommandId();
    this.logRequest("setContext", aRequest);
    let context = aRequest.value;
    if (context != "content" && context != "chrome") {
      this.sendError("invalid context", 500, null, this.command_id);
    }
    else {
      this.context = context;
      this.sendOk(this.command_id);
    }
  },

  /**
   * Returns a chrome sandbox that can be used by the execute_foo functions.
   *
   * @param nsIDOMWindow aWindow
   *        Window in which we will execute code
   * @param Marionette marionette
   *        Marionette test instance
   * @param object args
   *        Client given args
   * @return Sandbox
   *        Returns the sandbox
   */
  createExecuteSandbox: function MDA_createExecuteSandbox(aWindow, marionette, args, specialPowers, command_id) {
    try {
      args = this.curBrowser.elementManager.convertWrappedArguments(args, aWindow);
    }
    catch(e) {
      this.sendError(e.message, e.code, e.stack, command_id);
      return;
    }

    let _chromeSandbox = new Cu.Sandbox(aWindow,
       { sandboxPrototype: aWindow, wantXrays: false, sandboxName: ''});
    _chromeSandbox.__namedArgs = this.curBrowser.elementManager.applyNamedArgs(args);
    _chromeSandbox.__marionetteParams = args;
    _chromeSandbox.testUtils = utils;

    marionette.exports.forEach(function(fn) {
      try {
        _chromeSandbox[fn] = marionette[fn].bind(marionette);
      }
      catch(e) {
        _chromeSandbox[fn] = marionette[fn];
      }
    });

    _chromeSandbox.isSystemMessageListenerReady =
        function() { return systemMessageListenerReady; }

    if (specialPowers == true) {
      loader.loadSubScript("chrome://specialpowers/content/specialpowersAPI.js",
                           _chromeSandbox);
      loader.loadSubScript("chrome://specialpowers/content/SpecialPowersObserverAPI.js",
                           _chromeSandbox);
      loader.loadSubScript("chrome://specialpowers/content/ChromePowers.js",
                           _chromeSandbox);
    }

    return _chromeSandbox;
  },

  /**
   * Executes a script in the given sandbox.
   *
   * @param Sandbox sandbox
   *        Sandbox in which the script will run
   * @param string script
   *        The script to run
   * @param boolean directInject
   *        If true, then the script will be run as is,
   *        and not as a function body (as you would
   *        do using the WebDriver spec)
   * @param boolean async
   *        True if the script is asynchronous
   */
  executeScriptInSandbox: function MDA_executeScriptInSandbox(sandbox, script,
     directInject, async, command_id, timeout) {

    if (directInject && async &&
        (timeout == null || timeout == 0)) {
      this.sendError("Please set a timeout", 21, null, command_id);
      return;
    }

    if (this.importedScripts.exists()) {
      let stream = Cc["@mozilla.org/network/file-input-stream;1"].  
                    createInstance(Ci.nsIFileInputStream);
      stream.init(this.importedScripts, -1, 0, 0);
      let data = NetUtil.readInputStreamToString(stream, stream.available());
      script = data + script;
    }

    let res = Cu.evalInSandbox(script, sandbox, "1.8", "dummy file", 0);

    if (directInject && !async &&
        (res == undefined || res.passed == undefined)) {
      this.sendError("finish() not called", 500, null, command_id);
      return;
    }

    if (!async) {
      this.sendResponse(this.curBrowser.elementManager.wrapValue(res),
                        command_id);
    }
  },

  /**
   * Execute the given script either as a function body (executeScript)
   * or directly (for 'mochitest' like JS Marionette tests)
   *
   * @param object aRequest
   *        'value' member is the script to run
   *        'args' member holds the arguments to the script
   * @param boolean directInject
   *        if true, it will be run directly and not as a 
   *        function body
   */
  execute: function MDA_execute(aRequest, directInject) {
    let timeout = aRequest.scriptTimeout ? aRequest.scriptTimeout : this.scriptTimeout;
    let command_id = this.command_id = this.getCommandId();
    let script;
    this.logRequest("execute", aRequest);
    if (aRequest.newSandbox == undefined) {
      //if client does not send a value in newSandbox, 
      //then they expect the same behaviour as webdriver
      aRequest.newSandbox = true;
    }
    if (this.context == "content") {
      this.sendAsync("executeScript",
                     {
                       value: aRequest.value,
                       args: aRequest.args,
                       newSandbox: aRequest.newSandbox,
                       timeout: timeout,
                       specialPowers: aRequest.specialPowers,
                       filename: aRequest.filename,
                       line: aRequest.line
                     },
                     command_id);
      return;
    }

    let curWindow = this.getCurrentWindow();
    let marionette = new Marionette(this, curWindow, "chrome",
                                    this.marionetteLog,
                                    timeout, this.testName);
    let _chromeSandbox = this.createExecuteSandbox(curWindow,
                                                   marionette,
                                                   aRequest.args,
                                                   aRequest.specialPowers,
                                                   command_id);
    if (!_chromeSandbox)
      return;

    try {
      _chromeSandbox.finish = function chromeSandbox_finish() {
        return marionette.generate_results();
      };

      if (directInject) {
        script = aRequest.value;
      }
      else {
        script = "let func = function() {" +
                       aRequest.value + 
                     "};" +
                     "func.apply(null, __marionetteParams);";
      }
      this.executeScriptInSandbox(_chromeSandbox, script, directInject,
                                  false, command_id, timeout);
    }
    catch (e) {
      let error = this.createStackMessage(e,
                                          "execute_script",
                                          aRequest.filename,
                                          aRequest.line,
                                          script);
      this.sendError(error[0], 17, error[1], command_id);
    }
  },

  /**
   * Set the timeout for asynchronous script execution
   *
   * @param object aRequest
   *        'value' member is time in milliseconds to set timeout
   */
  setScriptTimeout: function MDA_setScriptTimeout(aRequest) {
    this.command_id = this.getCommandId();
    let timeout = parseInt(aRequest.value);
    if(isNaN(timeout)){
      this.sendError("Not a Number", 500, null, this.command_id);
    }
    else {
      this.scriptTimeout = timeout;
      this.sendOk(this.command_id);
    }
  },

  /**
   * execute pure JS script. Used to execute 'mochitest'-style Marionette tests.
   *
   * @param object aRequest
   *        'value' member holds the script to execute
   *        'args' member holds the arguments to the script
   *        'timeout' member will be used as the script timeout if it is given
   */
  executeJSScript: function MDA_executeJSScript(aRequest) {
    let timeout = aRequest.scriptTimeout ? aRequest.scriptTimeout : this.scriptTimeout;
    let command_id = this.command_id = this.getCommandId();
    //all pure JS scripts will need to call Marionette.finish() to complete the test.
    if (aRequest.newSandbox == undefined) {
      //if client does not send a value in newSandbox, 
      //then they expect the same behaviour as webdriver
      aRequest.newSandbox = true;
    }
    if (this.context == "chrome") {
      if (aRequest.async) {
        this.executeWithCallback(aRequest, aRequest.async);
      }
      else {
        this.execute(aRequest, true);
      }
    }
    else {
      this.sendAsync("executeJSScript",
                     {
                       value: aRequest.value,
                       args: aRequest.args,
                       newSandbox: aRequest.newSandbox,
                       async: aRequest.async,
                       timeout: timeout,
                       specialPowers: aRequest.specialPowers
                     },
                     command_id);
   }
  },

  /**
   * This function is used by executeAsync and executeJSScript to execute a script
   * in a sandbox. 
   * 
   * For executeJSScript, it will return a message only when the finish() method is called.
   * For executeAsync, it will return a response when marionetteScriptFinished/arguments[arguments.length-1] 
   * method is called, or if it times out.
   *
   * @param object aRequest
   *        'value' member holds the script to execute
   *        'args' member holds the arguments for the script
   * @param boolean directInject
   *        if true, it will be run directly and not as a 
   *        function body
   */
  executeWithCallback: function MDA_executeWithCallback(aRequest, directInject) {
    let timeout = aRequest.scriptTimeout ? aRequest.scriptTimeout : this.scriptTimeout;
    let command_id = this.command_id = this.getCommandId();
    let script;
    this.logRequest("executeWithCallback", aRequest);
    if (aRequest.newSandbox == undefined) {
      //if client does not send a value in newSandbox, 
      //then they expect the same behaviour as webdriver
      aRequest.newSandbox = true;
    }

    if (this.context == "content") {
      this.sendAsync("executeAsyncScript",
                     {
                       value: aRequest.value,
                       args: aRequest.args,
                       id: this.command_id,
                       newSandbox: aRequest.newSandbox,
                       timeout: timeout,
                       specialPowers: aRequest.specialPowers,
                       filename: aRequest.filename,
                       line: aRequest.line
                     },
                     command_id);
      return;
    }

    let curWindow = this.getCurrentWindow();
    let original_onerror = curWindow.onerror;
    let that = this;
    that.timeout = timeout;
    let marionette = new Marionette(this, curWindow, "chrome",
                                    this.marionetteLog,
                                    timeout, this.testName);
    marionette.command_id = this.command_id;

    function chromeAsyncReturnFunc(value, status, stacktrace) {
      if (that._emu_cbs && Object.keys(that._emu_cbs).length) {
        value = "Emulator callback still pending when finish() called";
        status = 500;
        that._emu_cbs = null;
      }

      if (value == undefined)
        value = null;
      if (that.command_id == marionette.command_id) {
        if (that.timer != null) {
          that.timer.cancel();
          that.timer = null;
        }

        curWindow.onerror = original_onerror;

        if (status == 0 || status == undefined) {
          that.sendToClient({from: that.actorID, value: that.curBrowser.elementManager.wrapValue(value), status: status},
                            marionette.command_id);
        }
        else {
          let error_msg = {message: value, status: status, stacktrace: stacktrace};
          that.sendToClient({from: that.actorID, error: error_msg},
                            marionette.command_id);
        }
      }
    }

    curWindow.onerror = function (errorMsg, url, lineNumber) {
      chromeAsyncReturnFunc(errorMsg + " at: " + url + " line: " + lineNumber, 17);
      return true;
    };

    function chromeAsyncFinish() {
      chromeAsyncReturnFunc(marionette.generate_results(), 0);
    }

    let _chromeSandbox = this.createExecuteSandbox(curWindow,
                                                   marionette,
                                                   aRequest.args,
                                                   aRequest.specialPowers,
                                                   command_id);
    if (!_chromeSandbox)
      return;

    try {

      this.timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
      if (this.timer != null) {
        this.timer.initWithCallback(function() {
          chromeAsyncReturnFunc("timed out", 28);
        }, that.timeout, Ci.nsITimer.TYPE_ONESHOT);
      }

      _chromeSandbox.returnFunc = chromeAsyncReturnFunc;
      _chromeSandbox.finish = chromeAsyncFinish;

      if (directInject) {
        script = aRequest.value;
      }
      else {
        script =  '__marionetteParams.push(returnFunc);'
                + 'let marionetteScriptFinished = returnFunc;'
                + 'let __marionetteFunc = function() {' + aRequest.value + '};'
                + '__marionetteFunc.apply(null, __marionetteParams);';
      }

      this.executeScriptInSandbox(_chromeSandbox, script, directInject,
                                  true, command_id, timeout);
    } catch (e) {
      let error = this.createStackMessage(e,
                                          "execute_async_script",
                                          aRequest.filename,
                                          aRequest.line,
                                          script);
      chromeAsyncReturnFunc(error[0], 17, error[1]);
    }
  },

  /**
   * Navigates to given url
   *
   * @param object aRequest
   *        'value' member holds the url to navigate to
   */
  goUrl: function MDA_goUrl(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context != "chrome") {
      aRequest.command_id = command_id;
      aRequest.pageTimeout = this.pageTimeout;
      this.sendAsync("goUrl", aRequest, command_id);
      return;
    }

    this.getCurrentWindow().location.href = aRequest.value;
    let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
    let start = new Date().getTime();
    let end = null;
    function checkLoad() { 
      end = new Date().getTime();
      let elapse = end - start;
      if (this.pageTimeout == null || elapse <= this.pageTimeout){
        if (curWindow.document.readyState == "complete") { 
          sendOk(command_id);
          return;
        }
        else{ 
          checkTimer.initWithCallback(checkLoad, 100, Ci.nsITimer.TYPE_ONE_SHOT);
        }
      }
      else{
        sendError("Error loading page", 13, null, command_id);
        return;
      }
    }//end
    checkTimer.initWithCallback(checkLoad, 100, Ci.nsITimer.TYPE_ONE_SHOT);
  },

  /**
   * Gets current url
   */
  getUrl: function MDA_getUrl() {
    this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      this.sendResponse(this.getCurrentWindow().location.href, this.command_id);
    }
    else {
      this.sendAsync("getUrl", {}, this.command_id);
    }
  },

  /**
   * Gets the current title of the window
   */
  getTitle: function MDA_getTitle() {
    this.command_id = this.getCommandId();
    if (this.context == "chrome"){
      var curWindow = this.getCurrentWindow();
      var title = curWindow.document.documentElement.getAttribute('title');
      this.sendResponse(title, this.command_id);
    }
    else {
      this.sendAsync("getTitle", {}, this.command_id);
    }
  },

  /**
   * Gets the current type of the window
   */
  getWindowType: function MDA_getWindowType() {
    this.command_id = this.getCommandId();
      var curWindow = this.getCurrentWindow();
      var type = curWindow.document.documentElement.getAttribute('windowtype');
      this.sendResponse(type, this.command_id);
  },

  /**
   * Gets the page source of the content document
   */
  getPageSource: function MDA_getPageSource(){
    this.command_id = this.getCommandId();
    if (this.context == "chrome"){
      let curWindow = this.getCurrentWindow();
      let XMLSerializer = curWindow.XMLSerializer; 
      let pageSource = new XMLSerializer().serializeToString(curWindow.document);
      this.sendResponse(pageSource, this.command_id);
    }
    else {
      this.sendAsync("getPageSource", {}, this.command_id);
    }
  },

  /**
   * Go back in history
   */
  goBack: function MDA_goBack() {
    this.command_id = this.getCommandId();
    this.sendAsync("goBack", {}, this.command_id);
  },

  /**
   * Go forward in history
   */
  goForward: function MDA_goForward() {
    this.command_id = this.getCommandId();
    this.sendAsync("goForward", {}, this.command_id);
  },

  /**
   * Refresh the page
   */
  refresh: function MDA_refresh() {
    this.command_id = this.getCommandId();
    this.sendAsync("refresh", {}, this.command_id);
  },

  /**
   * Get the current window's server-assigned ID
   */
  getWindow: function MDA_getWindow() {
    this.command_id = this.getCommandId();
    for (let i in this.browsers) {
      if (this.curBrowser == this.browsers[i]) {
        this.sendResponse(i, this.command_id);
      }
    }
  },

  /**
   * Get the server-assigned IDs of all available windows
   */
  getWindows: function MDA_getWindows() {
    this.command_id = this.getCommandId();
    let res = [];
    let winEn = this.getWinEnumerator(); 
    while(winEn.hasMoreElements()) {
      let foundWin = winEn.getNext();
      let winId = foundWin.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils).outerWindowID;
      winId = winId + ((appName == "B2G") ? '-b2g' : '');
      res.push(winId)
    }
    this.sendResponse(res, this.command_id);
  },

  /**
   * Switch to a window based on name or server-assigned id.
   * Searches based on name, then id.
   *
   * @param object aRequest
   *        'value' member holds the name or id of the window to switch to
   */
  switchToWindow: function MDA_switchToWindow(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    let winEn = this.getWinEnumerator(); 
    while(winEn.hasMoreElements()) {
      let foundWin = winEn.getNext();
      let winId = foundWin.QueryInterface(Ci.nsIInterfaceRequestor)
                          .getInterface(Ci.nsIDOMWindowUtils)
                          .outerWindowID;
      winId = winId + ((appName == "B2G") ? '-b2g' : '');
      if (aRequest.value == foundWin.name || aRequest.value == winId) {
        if (this.browsers[winId] == undefined) {
          //enable Marionette in that browser window
          this.startBrowser(foundWin, false);
        }
        else {
          utils.window = foundWin;
          this.curBrowser = this.browsers[winId];
        }
        this.sendOk(command_id);
        return;
      }
    }
    this.sendError("Unable to locate window " + aRequest.value, 23, null,
                   command_id);
  },
 
  /**
   * Switch to a given frame within the current window
   *
   * @param object aRequest
   *        'element' is the element to switch to
   *        'value' if element is not set, then this
   *                holds either the id, name or index 
   *                of the frame to switch to
   */
  switchToFrame: function MDA_switchToFrame(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    this.logRequest("switchToFrame", aRequest);
    let checkTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
    let curWindow = this.getCurrentWindow();
    let checkLoad = function() { 
      let errorRegex = /about:.+(error)|(blocked)\?/;
      if (curWindow.document.readyState == "complete") { 
        this.sendOk(command_id);
        return;
      } 
      else if (curWindow.document.readyState == "interactive" && errorRegex.exec(curWindow.document.baseURI)) {
        this.sendError("Error loading page", 13, null, command_id);
        return;
      }
      
      checkTimer.initWithCallback(checkLoad.bind(this), 100, Ci.nsITimer.TYPE_ONE_SHOT);
    }
    if (this.context == "chrome") {
      let foundFrame = null;
      if ((aRequest.value == null) && (aRequest.element == null)) {
        this.curFrame = null;
        if (aRequest.focus) {
          this.mainFrame.focus();
        }
        checkTimer.initWithCallback(checkLoad.bind(this), 100, Ci.nsITimer.TYPE_ONE_SHOT);
        return;
      }
      if (aRequest.element != undefined) {
        if (this.curBrowser.elementManager.seenItems[aRequest.element] != undefined) {
          let wantedFrame = this.curBrowser.elementManager.getKnownElement(aRequest.element, curWindow); //HTMLIFrameElement
          let numFrames = curWindow.frames.length;
          for (let i = 0; i < numFrames; i++) {
            if (curWindow.frames[i].frameElement == wantedFrame) {
              curWindow = curWindow.frames[i]; 
              this.curFrame = curWindow;
              if (aRequest.focus) {
                this.curFrame.focus();
              }
              checkTimer.initWithCallback(checkLoad.bind(this), 100, Ci.nsITimer.TYPE_ONE_SHOT);
              return;
          }
        }
      }
    }
    switch(typeof(aRequest.value)) {
      case "string" :
        let foundById = null;
        let numFrames = curWindow.frames.length;
        for (let i = 0; i < numFrames; i++) {
          //give precedence to name
          let frame = curWindow.frames[i];
          let frameElement = frame.frameElement;
          if (frame.name == aRequest.value) {
            foundFrame = i;
            break;
          } else if ((foundById == null) && (frameElement.id == aRequest.value)) {
            foundById = i;
          }
        }
        if ((foundFrame == null) && (foundById != null)) {
          foundFrame = foundById;
        }
        break;
      case "number":
        if (curWindow.frames[aRequest.value] != undefined) {
          foundFrame = aRequest.value;
        }
        break;
      }
      if (foundFrame != null) {
        curWindow = curWindow.frames[foundFrame];
        this.curFrame = curWindow;
        if (aRequest.focus) {
          this.curFrame.focus();
        }
        checkTimer.initWithCallback(checkLoad.bind(this), 100, Ci.nsITimer.TYPE_ONE_SHOT);
      } else {
        this.sendError("Unable to locate frame: " + aRequest.value, 8, null,
                       command_id);
      }
    }
    else {
      if ((!aRequest.value) && (!aRequest.element) &&
          (this.currentRemoteFrame !== null)) {
        // We're currently using a ChromeMessageSender for a remote frame, so this
        // request indicates we need to switch back to the top-level (parent) frame.
        // We'll first switch to the parent's (global) ChromeMessageBroadcaster, so
        // we send the message to the right listener.
        this.switchToGlobalMessageManager();
      }
      aRequest.command_id = command_id;
      this.sendAsync("switchToFrame", aRequest, command_id);
    }
  },

  /**
   * Set timeout for searching for elements
   *
   * @param object aRequest
   *        'value' holds the search timeout in milliseconds
   */
  setSearchTimeout: function MDA_setSearchTimeout(aRequest) {
    this.command_id = this.getCommandId();
    let timeout = parseInt(aRequest.value);
    if (isNaN(timeout)) {
      this.sendError("Not a Number", 500, null, this.command_id);
    }
    else {
      this.searchTimeout = timeout;
      this.sendOk(this.command_id);
    }
  },

  /**
   * Set timeout for page loading, searching and scripts
   *
   * @param object aRequest
   *        'type' hold the type of timeout
   *        'ms' holds the timeout in milliseconds
   */
  timeouts: function MDA_timeouts(aRequest){
    /*setTimeout*/
    this.command_id = this.getCommandId();
    let timeout_type = aRequest.timeoutType;
    let timeout = parseInt(aRequest.ms);
    if (isNaN(timeout)) {
      this.sendError("Not a Number", 500, null, this.command_id);
    }
    else {
      if (timeout_type == "implicit") {
        aRequest.value = aRequest.ms;
        this.setSearchTimeout(aRequest);
      }
      else if (timeout_type == "script") {
        aRequest.value = aRequest.ms;
        this.setScriptTimeout(aRequest);
      }
      else {
        this.pageTimeout = timeout;
        this.sendOk(this.command_id);
      }
    }
  },

  /**
   * Single Tap
   *
   * @param object aRequest
            'element' represents the ID of the element to single tap on
   */
  singleTap: function MDA_singleTap(aRequest) {
    this.command_id = this.getCommandId();
    let serId = aRequest.element;
    let x = aRequest.x;
    let y = aRequest.y;
    if (this.context == "chrome") {
      this.sendError("Command 'singleTap' is not available in chrome context", 500, null, this.command_id);
    }
    else {
      this.sendAsync("singleTap",
                     {
                       value: serId,
                       corx: x,
                       cory: y
                     },
                     this.command_id);
    }
  },

  /**
   * actionChain
   *
   * @param object aRequest
   *        'value' represents a nested array: inner array represents each event; outer array represents collection of events
   */
  actionChain: function MDA_actionChain(aRequest) {
    this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      this.sendError("Command 'actionChain' is not available in chrome context", 500, null, this.command_id);
    }
    else {
      this.sendAsync("actionChain",
                     {
                       chain: aRequest.chain,
                       nextId: aRequest.nextId
                     },
                     this.command_id);
    }
  },

  /**
   * multiAction
   *
   * @param object aRequest
   *        'value' represents a nested array: inner array represents each event;
   *        middle array represents collection of events for each finger
   *        outer array represents all the fingers
   */

  multiAction: function MDA_multiAction(aRequest) {
    this.command_id = this.getCommandId();
    if (this.context == "chrome") {
       this.sendError("Command 'multiAction' is not available in chrome context", 500, null, this.command_id);
    }
    else {
      this.sendAsync("multiAction",
                     {
                       value: aRequest.value,
                       maxlen: aRequest.max_length
                     },
                     this.command_id);
   }
 },

  /**
   * Find an element using the indicated search strategy.
   *
   * @param object aRequest
   *        'using' member indicates which search method to use
   *        'value' member is the value the client is looking for
   */
  findElement: function MDA_findElement(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      let id;
      try {
        let on_success = this.sendResponse.bind(this);
        let on_error = this.sendError.bind(this);
        id = this.curBrowser.elementManager.find(
                              this.getCurrentWindow(),
                              aRequest,
                              this.searchTimeout,
                              on_success,
                              on_error,
                              false,
                              command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
        return;
      }
    }
    else {
      this.sendAsync("findElementContent",
                     {
                       value: aRequest.value,
                       using: aRequest.using,
                       element: aRequest.element,
                       searchTimeout: this.searchTimeout
                     },
                     command_id);
    }
  },

  /**
   * Find elements using the indicated search strategy.
   *
   * @param object aRequest
   *        'using' member indicates which search method to use
   *        'value' member is the value the client is looking for
   */
  findElements: function MDA_findElements(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      let id;
      try {
        let on_success = this.sendResponse.bind(this);
        let on_error = this.sendError.bind(this);
        id = this.curBrowser.elementManager.find(this.getCurrentWindow(),
                                                 aRequest,
                                                 this.searchTimeout,
                                                 on_success,
                                                 on_error,
                                                 true,
                                                 command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
        return;
      }
    }
    else {
      this.sendAsync("findElementsContent",
                     {
                       value: aRequest.value,
                       using: aRequest.using,
                       element: aRequest.element,
                       searchTimeout: this.searchTimeout
                     },
                     command_id);
    }
  },

  /**
   * Return the active element on the page
   */
  getActiveElement: function MDA_getActiveElement(){
    let command_id = this.command_id = this.getCommandId();
    this.sendAsync("getActiveElement", {}, command_id);
  },

  /**
   * Send click event to element
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be clicked
   */
  clickElement: function MDA_clickElement(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        //NOTE: click atom fails, fall back to click() action
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        el.click();
        this.sendOk(command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      // We need to protect against the click causing an OOP frame to close. 
      // This fires the mozbrowserclose event when it closes so we need to 
      // listen for it and then just send an error back. The person making the
      // call should be aware something isnt right and handle accordingly
      let curWindow = this.getCurrentWindow();
      let self = this;
      this.mozBrowserClose = function() { 
        curWindow.removeEventListener('mozbrowserclose', self.mozBrowserClose, true);
        self.switchToGlobalMessageManager();
        self.sendError("The frame closed during the click, recovering to allow further communications", 500, null, command_id);
      };
      curWindow.addEventListener('mozbrowserclose', this.mozBrowserClose, true);
      this.sendAsync("clickElement",
                     { element: aRequest.element },
                     command_id);
    }
  },

  /**
   * Get a given attribute of an element
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be inspected
   *        'name' member holds the name of the attribute to retrieve
   */
  getElementAttribute: function MDA_getElementAttribute(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        this.sendResponse(utils.getElementAttribute(el, aRequest.name),
                          command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("getElementAttribute",
                     {
                       element: aRequest.element,
                       name: aRequest.name
                     },
                     command_id);
    }
  },

  /**
   * Get the text of an element, if any. Includes the text of all child elements.
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be inspected 
   */
  getElementText: function MDA_getElementText(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      //Note: for chrome, we look at text nodes, and any node with a "label" field
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        let lines = [];
        this.getVisibleText(el, lines);
        lines = lines.join("\n");
        this.sendResponse(lines, command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("getElementText",
                     { element: aRequest.element },
                     command_id);
    }
  },

  /**
   * Get the tag name of the element.
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be inspected 
   */
  getElementTagName: function MDA_getElementTagName(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        this.sendResponse(el.tagName.toLowerCase(), command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("getElementTagName",
                     { element: aRequest.element },
                     command_id);
    }
  },

  /**
   * Check if element is displayed
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be checked 
   */
  isElementDisplayed: function MDA_isElementDisplayed(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        this.sendResponse(utils.isElementDisplayed(el), command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("isElementDisplayed",
                     { element:aRequest.element },
                     command_id);
    }
  },

  /**
   * Return the property of the computed style of an element
   *
   * @param object aRequest
   *               'element' member holds the reference id to
   *               the element that will be checked
   *               'propertyName' is the CSS rule that is being requested
   */
  getElementValueOfCssProperty: function MDA_getElementValueOfCssProperty(aRequest){
    let command_id = this.command_id = this.getCommandId();
    this.sendAsync("getElementValueOfCssProperty",
                   {element: aRequest.element, propertyName: aRequest.propertyName},
                   command_id);
  },

  /**
   * Check if element is enabled
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be checked
   */
  isElementEnabled: function MDA_isElementEnabled(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        //Selenium atom doesn't quite work here
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        if (el.disabled != undefined) {
          this.sendResponse(!!!el.disabled, command_id);
        }
        else {
        this.sendResponse(true, command_id);
        }
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("isElementEnabled",
                     { element:aRequest.element },
                     command_id);
    }
  },

  /**
   * Check if element is selected
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be checked
   */
  isElementSelected: function MDA_isElementSelected(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        //Selenium atom doesn't quite work here
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        if (el.checked != undefined) {
          this.sendResponse(!!el.checked, command_id);
        }
        else if (el.selected != undefined) {
          this.sendResponse(!!el.selected, command_id);
        }
        else {
          this.sendResponse(true, command_id);
        }
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("isElementSelected",
                     { element:aRequest.element },
                     command_id);
    }
  },

  getElementSize: function MDA_getElementSize(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        let clientRect = el.getBoundingClientRect();  
        this.sendResponse({width: clientRect.width, height: clientRect.height},
                          command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("getElementSize",
                     { element:aRequest.element },
                     command_id);
    }
  },

  /**
   * Send key presses to element after focusing on it
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be checked
   *        'value' member holds the value to send to the element
   */
  sendKeysToElement: function MDA_sendKeysToElement(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        el.focus();
        utils.sendString(aRequest.value.join(""), utils.window);
        this.sendOk(command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("sendKeysToElement",
                     {
                       element:aRequest.element,
                       value: aRequest.value
                     },
                     command_id);
    }
  },

  /**
   * Sets the test name
   *
   * The test name is used in logging messages.
   */
  setTestName: function MDA_setTestName(aRequest) {
    this.command_id = this.getCommandId();
    this.logRequest("setTestName", aRequest);
    this.testName = aRequest.value;
    this.sendAsync("setTestName",
                   { value: aRequest.value },
                   this.command_id);
  },

  /**
   * Clear the text of an element
   *
   * @param object aRequest
   *        'element' member holds the reference id to
   *        the element that will be cleared 
   */
  clearElement: function MDA_clearElement(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      //the selenium atom doesn't work here
      try {
        let el = this.curBrowser.elementManager.getKnownElement(
            aRequest.element, this.getCurrentWindow());
        if (el.nodeName == "textbox") {
          el.value = "";
        }
        else if (el.nodeName == "checkbox") {
          el.checked = false;
        }
        this.sendOk(command_id);
      }
      catch (e) {
        this.sendError(e.message, e.code, e.stack, command_id);
      }
    }
    else {
      this.sendAsync("clearElement",
                     { element:aRequest.element },
                     command_id);
    }
  },

  getElementPosition: function MDA_getElementPosition(aRequest) {
    this.command_id = this.getCommandId();
    this.sendAsync("getElementPosition",
                   { element:aRequest.element },
                   this.command_id);
  },

  /**
   * Add a cookie to the document.
   */
  addCookie: function MDA_addCookie(aRequest) {
    this.command_id = this.getCommandId();
    this.sendAsync("addCookie",
                   { cookie:aRequest.cookie },
                   this.command_id);
  },

  /**
   * Get all visible cookies for a document
   */
  getAllCookies: function MDA_getAllCookies() {
    this.command_id = this.getCommandId();
    this.sendAsync("getAllCookies", {}, this.command_id);
  },

  /**
   * Delete all cookies that are visible to a document
   */
  deleteAllCookies: function MDA_deleteAllCookies() {
    this.command_id = this.getCommandId();
    this.sendAsync("deleteAllCookies", {}, this.command_id);
  },

  /**
   * Delete a cookie by name
   */
  deleteCookie: function MDA_deleteCookie(aRequest) {
    this.command_id = this.getCommandId();
    this.sendAsync("deleteCookie",
                   { name:aRequest.name },
                   this.command_id);
  },

  /**
   * Closes the Browser Window.
   *
   * If it is B2G it returns straight away and does not do anything
   *
   * If is desktop it calculates how many windows are open and if there is only 
   * 1 then it deletes the session otherwise it closes the window
   */
  closeWindow: function MDA_closeWindow() {
    let command_id = this.command_id = this.getCommandId();
    if (appName == "B2G") {
      // We can't close windows so just return
      this.sendOk(command_id);
    }
    else {
      // Get the total number of windows
      let numOpenWindows = 0;
      let winEnum = this.getWinEnumerator();
      while (winEnum.hasMoreElements()) {
        numOpenWindows += 1;
        winEnum.getNext(); 
      }

      // if there is only 1 window left, delete the session
      if (numOpenWindows === 1){
        this.deleteSession();
        return;
      }

      try{
        this.messageManager.removeDelayedFrameScript(FRAME_SCRIPT); 
        this.getCurrentWindow().close();
        this.sendOk(command_id);
      }
      catch (e) {
        this.sendError("Could not close window: " + e.message, 13, e.stack,
                       command_id);
      }
    }
  }, 

  /**
   * Deletes the session.
   * 
   * If it is a desktop environment, it will close the session's tab and close all listeners
   *
   * If it is a B2G environment, it will make the main content listener sleep, and close
   * all other listeners. The main content listener persists after disconnect (it's the homescreen),
   * and can safely be reused.
   */
  deleteSession: function MDA_deleteSession() {
    let command_id = this.command_id = this.getCommandId();
    if (this.curBrowser != null) {
      if (appName == "B2G") {
        this.globalMessageManager.broadcastAsyncMessage(
            "Marionette:sleepSession" + this.curBrowser.mainContentId, {});
        this.curBrowser.knownFrames.splice(
            this.curBrowser.knownFrames.indexOf(this.curBrowser.mainContentId), 1);
      }
      else {
        //don't set this pref for B2G since the framescript can be safely reused
        Services.prefs.setBoolPref("marionette.contentListener", false);
      }
      this.curBrowser.closeTab();
      //delete session in each frame in each browser
      for (let win in this.browsers) {
        for (let i in this.browsers[win].knownFrames) {
          this.globalMessageManager.broadcastAsyncMessage("Marionette:deleteSession" + this.browsers[win].knownFrames[i], {});
        }
      }
      let winEnum = this.getWinEnumerator();
      while (winEnum.hasMoreElements()) {
        winEnum.getNext().messageManager.removeDelayedFrameScript(FRAME_SCRIPT); 
      }
    }
    this.sendOk(command_id);
    this.removeMessageManagerListeners(this.globalMessageManager);
    this.switchToGlobalMessageManager();
    // reset frame to the top-most frame
    this.curFrame = null;
    if (this.mainFrame) {
      this.mainFrame.focus();
    }
    this.curBrowser = null;
    try {
      this.importedScripts.remove(false);
    }
    catch (e) {
    }
  },

  /**
   * Returns the current status of the Application Cache
   */
  getAppCacheStatus: function MDA_getAppCacheStatus(aRequest) {
    this.command_id = this.getCommandId();
    this.sendAsync("getAppCacheStatus", {}, this.command_id);
  },

  _emu_cb_id: 0,
  _emu_cbs: null,
  runEmulatorCmd: function runEmulatorCmd(cmd, callback) {
    if (callback) {
      if (!this._emu_cbs) {
        this._emu_cbs = {};
      }
      this._emu_cbs[this._emu_cb_id] = callback;
    }
    this.sendToClient({emulator_cmd: cmd, id: this._emu_cb_id}, -1);
    this._emu_cb_id += 1;
  },

  emulatorCmdResult: function emulatorCmdResult(message) {
    if (this.context != "chrome") {
      this.sendAsync("emulatorCmdResult", message, -1);
      return;
    }

    if (!this._emu_cbs) {
      return;
    }

    let cb = this._emu_cbs[message.id];
    delete this._emu_cbs[message.id];
    if (!cb) {
      return;
    }
    try {
      cb(message.result);
    }
    catch(e) {
      this.sendError(e.message, e.code, e.stack, -1);
      return;
    }
  },
  
  importScript: function MDA_importScript(aRequest) {
    let command_id = this.command_id = this.getCommandId();
    if (this.context == "chrome") {
      let file;
      if (this.importedScripts.exists()) {
        file = FileUtils.openFileOutputStream(this.importedScripts,
            FileUtils.MODE_APPEND | FileUtils.MODE_WRONLY);
      }
      else {
        //Note: The permission bits here don't actually get set (bug 804563)
        this.importedScripts.createUnique(
            Components.interfaces.nsIFile.NORMAL_FILE_TYPE, parseInt("0666", 8));
        file = FileUtils.openFileOutputStream(this.importedScripts,
            FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE);
        this.importedScripts.permissions = parseInt("0666", 8); //actually set permissions
      }
      file.write(aRequest.script, aRequest.script.length);
      file.close();
      this.sendOk(command_id);
    }
    else {
      this.sendAsync("importScript",
                     { script: aRequest.script },
                     command_id);
    }
  },

  /**
   * Takes a screenshot of a DOM node. If there is no node given a screenshot
   * of the window will be taken.
   */
  screenShot: function MDA_saveScreenshot(aRequest) {
    this.command_id = this.getCommandId();
    this.sendAsync("screenShot",
                   {
                     element: aRequest.element,
                     highlights: aRequest.highlights
                   },
                   this.command_id);
  },

  /**
   * Helper function to convert an outerWindowID into a UID that Marionette
   * tracks.
   */
  generateFrameId: function MDA_generateFrameId(id) {
    let uid = id + (appName == "B2G" ? "-b2g" : "");
    return uid;
  },

  /**
   * Receives all messages from content messageManager
   */
  receiveMessage: function MDA_receiveMessage(message) {
    // We need to just check if we need to remove the mozbrowserclose listener
    if (this.mozBrowserClose !== null){
      let curWindow = this.getCurrentWindow();
      curWindow.removeEventListener('mozbrowserclose', this.mozBrowserClose, true);
      this.mozBrowserClose = null;
    }

    switch (message.name) {
      case "Marionette:done":
        this.sendResponse(message.json.value, message.json.command_id);
        break;
      case "Marionette:ok":
        this.sendOk(message.json.command_id);
        break;
      case "Marionette:error":
        this.sendError(message.json.message, message.json.status, message.json.stacktrace, message.json.command_id);
        break;
      case "Marionette:log":
        //log server-side messages
        logger.info(message.json.message);
        break;
      case "Marionette:shareData":
        //log messages from tests
        if (message.json.log) {
          this.marionetteLog.addLogs(message.json.log);
        }
        break;
      case "Marionette:runEmulatorCmd":
        this.sendToClient(message.json, -1);
        break;
      case "Marionette:switchToFrame":
        // Switch to a remote frame.
        let frameWindow = Services.wm.getOuterWindowWithId(message.json.win);
        let thisFrame = frameWindow.document.getElementsByTagName("iframe")[message.json.frame];
        let mm = thisFrame.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader.messageManager;

        // See if this frame already has our frame script loaded in it; if so,
        // just wake it up.
        for (let i = 0; i < remoteFrames.length; i++) {
          let frame = remoteFrames[i];
          if ((frame.messageManager == mm)) {
            this.currentRemoteFrame = frame;
            this.currentRemoteFrame.command_id = message.json.command_id;
            this.messageManager = frame.messageManager;
            this.addMessageManagerListeners(this.messageManager);
            this.messageManager.sendAsyncMessage("Marionette:restart", {});
            return;
          }
        }

        // Load the frame script in this frame, and set the frame's ChromeMessageSender
        // as the active message manager.
        this.addMessageManagerListeners(mm);
        mm.loadFrameScript(FRAME_SCRIPT, true);
        this.messageManager = mm;
        let aFrame = new MarionetteRemoteFrame(message.json.win, message.json.frame);
        aFrame.messageManager = this.messageManager;
        aFrame.command_id = message.json.command_id;
        remoteFrames.push(aFrame);
        this.currentRemoteFrame = aFrame;
        break;
      case "Marionette:register":
        // This code processes the content listener's registration information
        // and either accepts the listener, or ignores it
        let nullPrevious = (this.curBrowser.curFrameId == null);
        let listenerWindow =
          Services.wm.getOuterWindowWithId(message.json.value);

        if (!listenerWindow || (listenerWindow.location.href != message.json.href) &&
            (this.currentRemoteFrame !== null)) {
          // The outerWindowID from an OOP frame will not be meaningful to
          // the parent process here, since each process maintains its own
          // independent window list.  So, it will either be null (!listenerWindow)
          // or it will point to some random window, which will hopefully 
          // cause an href mistmach.  Currently this only happens
          // in B2G for OOP frames registered in Marionette:switchToFrame, so
          // we'll acknowledge the switchToFrame message here.
          // XXX: Should have a better way of determining that this message
          // is from a remote frame.
          this.currentRemoteFrame.targetFrameId = this.generateFrameId(message.json.value);
          this.sendOk(this.currentRemoteFrame.command_id);
        }

        let browserType;
        try {
          browserType = message.target.getAttribute("type");
        } catch (ex) {
          // browserType remains undefined.
        }
        let reg = {};
        if (!browserType || browserType != "content") {
          reg.id = this.curBrowser.register(this.generateFrameId(message.json.value),
                                            listenerWindow);
        }
        this.curBrowser.elementManager.seenItems[reg.id] = Cu.getWeakReference(listenerWindow);
        reg.importedScripts = this.importedScripts.path;
        if (nullPrevious && (this.curBrowser.curFrameId != null)) {
          if (!this.sendAsync("newSession",
                              { B2G: (appName == "B2G") },
                              this.newSessionCommandId)) {
            return;
          }
          if (this.curBrowser.newSession) {
            this.sendResponse(reg.id, this.newSessionCommandId);
            this.newSessionCommandId = null;
          }
        }
        return reg;
    }
  }
};

MarionetteServerConnection.prototype.requestTypes = {
  "getMarionetteID": MarionetteServerConnection.prototype.getMarionetteID,
  "sayHello": MarionetteServerConnection.prototype.sayHello,
  "newSession": MarionetteServerConnection.prototype.newSession,
  "getSessionCapabilities": MarionetteServerConnection.prototype.getSessionCapabilities,
  "getStatus": MarionetteServerConnection.prototype.getStatus,
  "log": MarionetteServerConnection.prototype.log,
  "getLogs": MarionetteServerConnection.prototype.getLogs,
  "setContext": MarionetteServerConnection.prototype.setContext,
  "executeScript": MarionetteServerConnection.prototype.execute,
  "setScriptTimeout": MarionetteServerConnection.prototype.setScriptTimeout,
  "timeouts": MarionetteServerConnection.prototype.timeouts,
  "singleTap": MarionetteServerConnection.prototype.singleTap,
  "actionChain": MarionetteServerConnection.prototype.actionChain,
  "multiAction": MarionetteServerConnection.prototype.multiAction,
  "executeAsyncScript": MarionetteServerConnection.prototype.executeWithCallback,
  "executeJSScript": MarionetteServerConnection.prototype.executeJSScript,
  "setSearchTimeout": MarionetteServerConnection.prototype.setSearchTimeout,
  "findElement": MarionetteServerConnection.prototype.findElement,
  "findElements": MarionetteServerConnection.prototype.findElements,
  "clickElement": MarionetteServerConnection.prototype.clickElement,
  "getElementAttribute": MarionetteServerConnection.prototype.getElementAttribute,
  "getElementText": MarionetteServerConnection.prototype.getElementText,
  "getElementTagName": MarionetteServerConnection.prototype.getElementTagName,
  "isElementDisplayed": MarionetteServerConnection.prototype.isElementDisplayed,
  "getElementValueOfCssProperty": MarionetteServerConnection.prototype.getElementValueOfCssProperty,
  "getElementSize": MarionetteServerConnection.prototype.getElementSize,
  "isElementEnabled": MarionetteServerConnection.prototype.isElementEnabled,
  "isElementSelected": MarionetteServerConnection.prototype.isElementSelected,
  "sendKeysToElement": MarionetteServerConnection.prototype.sendKeysToElement,
  "getElementPosition": MarionetteServerConnection.prototype.getElementPosition,
  "clearElement": MarionetteServerConnection.prototype.clearElement,
  "getTitle": MarionetteServerConnection.prototype.getTitle,
  "getWindowType": MarionetteServerConnection.prototype.getWindowType,
  "getPageSource": MarionetteServerConnection.prototype.getPageSource,
  "goUrl": MarionetteServerConnection.prototype.goUrl,
  "getUrl": MarionetteServerConnection.prototype.getUrl,
  "goBack": MarionetteServerConnection.prototype.goBack,
  "goForward": MarionetteServerConnection.prototype.goForward,
  "refresh":  MarionetteServerConnection.prototype.refresh,
  "getWindow":  MarionetteServerConnection.prototype.getWindow,
  "getWindows":  MarionetteServerConnection.prototype.getWindows,
  "switchToFrame": MarionetteServerConnection.prototype.switchToFrame,
  "switchToWindow": MarionetteServerConnection.prototype.switchToWindow,
  "deleteSession": MarionetteServerConnection.prototype.deleteSession,
  "emulatorCmdResult": MarionetteServerConnection.prototype.emulatorCmdResult,
  "importScript": MarionetteServerConnection.prototype.importScript,
  "getAppCacheStatus": MarionetteServerConnection.prototype.getAppCacheStatus,
  "closeWindow": MarionetteServerConnection.prototype.closeWindow,
  "setTestName": MarionetteServerConnection.prototype.setTestName,
  "screenShot": MarionetteServerConnection.prototype.screenShot,
  "addCookie": MarionetteServerConnection.prototype.addCookie,
  "getAllCookies": MarionetteServerConnection.prototype.getAllCookies,
  "deleteAllCookies": MarionetteServerConnection.prototype.deleteAllCookies,
  "deleteCookie": MarionetteServerConnection.prototype.deleteCookie,
  "getActiveElement": MarionetteServerConnection.prototype.getActiveElement
};

/**
 * Creates a BrowserObj. BrowserObjs handle interactions with the
 * browser, according to the current environment (desktop, b2g, etc.)
 *
 * @param nsIDOMWindow win
 *        The window whose browser needs to be accessed
 */

function BrowserObj(win) {
  this.DESKTOP = "desktop";
  this.B2G = "B2G";
  this.browser;
  this.tab = null;
  this.window = win;
  this.knownFrames = [];
  this.curFrameId = null;
  this.startPage = "about:blank";
  this.mainContentId = null; // used in B2G to identify the homescreen content page
  this.newSession = true; //used to set curFrameId upon new session
  this.elementManager = new ElementManager([SELECTOR, NAME, LINK_TEXT, PARTIAL_LINK_TEXT]);
  this.setBrowser(win);
}

BrowserObj.prototype = {
  /**
   * Set the browser if the application is not B2G
   *
   * @param nsIDOMWindow win
   *        current window reference
   */
  setBrowser: function BO_setBrowser(win) {
    switch (appName) {
      case "Firefox":
        this.browser = win.gBrowser;
        break;
      case "Fennec":
        this.browser = win.BrowserApp;
        break;
    }
  },
  /**
   * Called when we start a session with this browser.
   *
   * In a desktop environment, if newTab is true, it will start 
   * a new 'about:blank' tab and change focus to this tab.
   *
   * This will also set the active messagemanager for this object
   *
   * @param boolean newTab
   *        If true, create new tab
   */
  startSession: function BO_startSession(newTab, win, callback) {
    if (appName != "Firefox") {
      callback(win, newTab);
    }
    else if (newTab) {
      this.tab = this.addTab(this.startPage);
      //if we have a new tab, make it the selected tab
      this.browser.selectedTab = this.tab;
      let newTabBrowser = this.browser.getBrowserForTab(this.tab);
      // wait for tab to be loaded
      newTabBrowser.addEventListener("load", function onLoad() {
        newTabBrowser.removeEventListener("load", onLoad, true);
        callback(win, newTab);
      }, true);
    }
    else {
      //set this.tab to the currently focused tab
      if (this.browser != undefined && this.browser.selectedTab != undefined) {
        this.tab = this.browser.selectedTab;
      }
      callback(win, newTab);
    }
  },

  /**
   * Closes current tab
   */
  closeTab: function BO_closeTab() {
    if (this.tab != null && (appName != "B2G")) {
      this.browser.removeTab(this.tab);
      this.tab = null;
    }
  },

  /**
   * Opens a tab with given uri
   *
   * @param string uri
   *      URI to open
   */
  addTab: function BO_addTab(uri) {
    return this.browser.addTab(uri, true);
  },

  /**
   * Loads content listeners if we don't already have them
   *
   * @param string script
   *        path of script to load
   * @param nsIDOMWindow frame
   *        frame to load the script in
   */
  loadFrameScript: function BO_loadFrameScript(script, frame) {
    frame.window.messageManager.loadFrameScript(script, true);
    Services.prefs.setBoolPref("marionette.contentListener", true);
  },

  /**
   * Registers a new frame, and sets its current frame id to this frame
   * if it is not already assigned, and if a) we already have a session 
   * or b) we're starting a new session and it is the right start frame.
   *
   * @param string uid
   *        frame uid
   * @param object frameWindow
   *        the DOMWindow object of the frame that's being registered
   */
  register: function BO_register(uid, frameWindow) {
    if (this.curFrameId == null) {
      // If we're setting up a new session on Firefox, we only process the
      // registration for this frame if it belongs to the tab we've just
      // created.
      if ((!this.newSession) ||
          (this.newSession &&
            ((appName != "Firefox") ||
             frameWindow == this.browser.getBrowserForTab(this.tab).contentWindow))) {
        this.curFrameId = uid;
        this.mainContentId = uid;
      }
    }
    this.knownFrames.push(uid); //used to delete sessions
    return uid;
  },
}

/**
 * Marionette server -- this class holds a reference to a socket and creates
 * MarionetteServerConnection objects as needed.
 */
this.MarionetteServer = function MarionetteServer(port, forceLocal) {
  let flags = Ci.nsIServerSocket.KeepWhenOffline;
  if (forceLocal) {
    flags |= Ci.nsIServerSocket.LoopbackOnly;
  }
  let socket = new ServerSocket(port, flags, 4);
  logger.info("Listening on port " + socket.port + "\n");
  socket.asyncListen(this);
  this.listener = socket;
  this.nextConnId = 0;
  this.connections = {};
};

MarionetteServer.prototype = {
  onSocketAccepted: function(serverSocket, clientSocket)
  {
    logger.debug("accepted connection on " + clientSocket.host + ":" + clientSocket.port);

    let input = clientSocket.openInputStream(0, 0, 0);
    let output = clientSocket.openOutputStream(0, 0, 0);
    let aTransport = new DebuggerTransport(input, output);
    let connID = "conn" + this.nextConnID++ + '.';
    let conn = new MarionetteServerConnection(connID, aTransport, this);
    this.connections[connID] = conn;

    // Create a root actor for the connection and send the hello packet.
    conn.sayHello();
    aTransport.ready();
  },

  closeListener: function() {
    this.listener.close();
    this.listener = null;
  },

  _connectionClosed: function DS_connectionClosed(aConnection) {
    delete this.connections[aConnection.prefix];
  }
};