The Tor Browser: toolkit/devtools/server/main.js@6474c204b198 (annotated)

toolkit/devtools/server/main.js@6474c204b198 (annotated)

toolkit/devtools/server/main.js

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: javascript; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ft=javascript ts=2 et sw=2 tw=80: */
 /* 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";
 /**
  * Toolkit glue for the remote debugging protocol, loaded into the
  * debugging global.
  */
 let { Ci, Cc, CC, Cu, Cr } = require("chrome");
 let Debugger = require("Debugger");
 let Services = require("Services");
 let { ActorPool } = require("devtools/server/actors/common");
 let { DebuggerTransport, LocalDebuggerTransport, ChildDebuggerTransport } = require("devtools/server/transport");
 let DevToolsUtils = require("devtools/toolkit/DevToolsUtils");
 let { dumpn, dbg_assert } = DevToolsUtils;
 let Services = require("Services");
 let EventEmitter = require("devtools/toolkit/event-emitter");
 // Until all Debugger server code is converted to SDK modules,
 // imports Components.* alias from chrome module.
 var { Ci, Cc, CC, Cu, Cr } = require("chrome");
 // On B2G, `this` != Global scope, so `Ci` won't be binded on `this`
 // (i.e. this.Ci is undefined) Then later, when using loadSubScript,
 // Ci,... won't be defined for sub scripts.
 this.Ci = Ci;
 this.Cc = Cc;
 this.CC = CC;
 this.Cu = Cu;
 this.Cr = Cr;
 this.Debugger = Debugger;
 this.Services = Services;
 this.ActorPool = ActorPool;
 this.DevToolsUtils = DevToolsUtils;
 this.dumpn = dumpn;
 this.dbg_assert = dbg_assert;
 // Overload `Components` to prevent SDK loader exception on Components
 // object usage
 Object.defineProperty(this, "Components", {
   get: function () require("chrome").components
 });
 const DBG_STRINGS_URI = "chrome://global/locale/devtools/debugger.properties";
 const nsFile = CC("@mozilla.org/file/local;1", "nsIFile", "initWithPath");
 Cu.import("resource://gre/modules/reflect.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 dumpn.wantLogging = Services.prefs.getBoolPref("devtools.debugger.log");
 Cu.import("resource://gre/modules/devtools/deprecated-sync-thenables.js");
 function loadSubScript(aURL)
 {
   try {
     let loader = Cc["@mozilla.org/moz/jssubscript-loader;1"]
       .getService(Ci.mozIJSSubScriptLoader);
     loader.loadSubScript(aURL, this);
   } catch(e) {
     let errorStr = "Error loading: " + aURL + ":\n" +
                    (e.fileName ? "at " + e.fileName + " : " + e.lineNumber + "\n" : "") +
                    e + " - " + e.stack + "\n";
     dump(errorStr);
     Cu.reportError(errorStr);
     throw e;
   }
 }
 let events = require("sdk/event/core");
 let {defer, resolve, reject, all} = require("devtools/toolkit/deprecated-sync-thenables");
 this.defer = defer;
 this.resolve = resolve;
 this.reject = reject;
 this.all = all;
 Cu.import("resource://gre/modules/devtools/SourceMap.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "console",
                                   "resource://gre/modules/devtools/Console.jsm");
 XPCOMUtils.defineLazyGetter(this, "NetworkMonitorManager", () => {
   return require("devtools/toolkit/webconsole/network-monitor").NetworkMonitorManager;
 });
 // XPCOM constructors
 const ServerSocket = CC("@mozilla.org/network/server-socket;1",
                         "nsIServerSocket",
                         "initSpecialConnection");
 const UnixDomainServerSocket = CC("@mozilla.org/network/server-socket;1",
                                   "nsIServerSocket",
                                   "initWithFilename");
 var gRegisteredModules = Object.create(null);
 /**
  * The ModuleAPI object is passed to modules loaded using the
  * DebuggerServer.registerModule() API.  Modules can use this
  * object to register actor factories.
  * Factories registered through the module API will be removed
  * when the module is unregistered or when the server is
  * destroyed.
  */
 function ModuleAPI() {
   let activeTabActors = new Set();
   let activeGlobalActors = new Set();
   return {
     // See DebuggerServer.addGlobalActor for a description.
     addGlobalActor: function(factory, name) {
       DebuggerServer.addGlobalActor(factory, name);
       activeGlobalActors.add(factory);
     },
     // See DebuggerServer.removeGlobalActor for a description.
     removeGlobalActor: function(factory) {
       DebuggerServer.removeGlobalActor(factory);
       activeGlobalActors.delete(factory);
     },
     // See DebuggerServer.addTabActor for a description.
     addTabActor: function(factory, name) {
       DebuggerServer.addTabActor(factory, name);
       activeTabActors.add(factory);
     },
     // See DebuggerServer.removeTabActor for a description.
     removeTabActor: function(factory) {
       DebuggerServer.removeTabActor(factory);
       activeTabActors.delete(factory);
     },
     // Destroy the module API object, unregistering any
     // factories registered by the module.
     destroy: function() {
       for (let factory of activeTabActors) {
         DebuggerServer.removeTabActor(factory);
       }
       activeTabActors = null;
       for (let factory of activeGlobalActors) {
         DebuggerServer.removeGlobalActor(factory);
       }
       activeGlobalActors = null;
     }
   }
 };
 /***
  * Public API
  */
 var DebuggerServer = {
   _listener: null,
   _initialized: false,
   _transportInitialized: false,
   xpcInspector: null,
   // Number of currently open TCP connections.
   _socketConnections: 0,
   // Map of global actor names to actor constructors provided by extensions.
   globalActorFactories: {},
   // Map of tab actor names to actor constructors provided by extensions.
   tabActorFactories: {},
   LONG_STRING_LENGTH: 10000,
   LONG_STRING_INITIAL_LENGTH: 1000,
   LONG_STRING_READ_LENGTH: 65 * 1024,
   /**
    * A handler function that prompts the user to accept or decline the incoming
    * connection.
    */
   _allowConnection: null,
   /**
    * The windowtype of the chrome window to use for actors that use the global
    * window (i.e the global style editor). Set this to your main window type,
    * for example "navigator:browser".
    */
   chromeWindowType: null,
   /**
    * Prompt the user to accept or decline the incoming connection. This is the
    * default implementation that products embedding the debugger server may
    * choose to override.
    *
    * @return true if the connection should be permitted, false otherwise
    */
   _defaultAllowConnection: function DS__defaultAllowConnection() {
     let title = L10N.getStr("remoteIncomingPromptTitle");
     let msg = L10N.getStr("remoteIncomingPromptMessage");
     let disableButton = L10N.getStr("remoteIncomingPromptDisable");
     let prompt = Services.prompt;
     let flags = prompt.BUTTON_POS_0 * prompt.BUTTON_TITLE_OK +
                 prompt.BUTTON_POS_1 * prompt.BUTTON_TITLE_CANCEL +
                 prompt.BUTTON_POS_2 * prompt.BUTTON_TITLE_IS_STRING +
                 prompt.BUTTON_POS_1_DEFAULT;
     let result = prompt.confirmEx(null, title, msg, flags, null, null,
                                   disableButton, null, { value: false });
     if (result == 0) {
       return true;
     }
     if (result == 2) {
       DebuggerServer.closeListener(true);
       Services.prefs.setBoolPref("devtools.debugger.remote-enabled", false);
     }
     return false;
   },
   /**
    * Initialize the debugger server.
    *
    * @param function aAllowConnectionCallback
    *        The embedder-provider callback, that decides whether an incoming
    *        remote protocol conection should be allowed or refused.
    */
   init: function DS_init(aAllowConnectionCallback) {
     if (this.initialized) {
       return;
     }
     this.xpcInspector = Cc["@mozilla.org/jsinspector;1"].getService(Ci.nsIJSInspector);
     this.initTransport(aAllowConnectionCallback);
     this.addActors("resource://gre/modules/devtools/server/actors/root.js");
     this._initialized = true;
   },
   protocol: require("devtools/server/protocol"),
   /**
    * Initialize the debugger server's transport variables.  This can be
    * in place of init() for cases where the jsdebugger isn't needed.
    *
    * @param function aAllowConnectionCallback
    *        The embedder-provider callback, that decides whether an incoming
    *        remote protocol conection should be allowed or refused.
    */
   initTransport: function DS_initTransport(aAllowConnectionCallback) {
     if (this._transportInitialized) {
       return;
     }
     this._connections = {};
     this._nextConnID = 0;
     this._transportInitialized = true;
     this._allowConnection = aAllowConnectionCallback ?
                             aAllowConnectionCallback :
                             this._defaultAllowConnection;
   },
   get initialized() this._initialized,
   /**
    * Performs cleanup tasks before shutting down the debugger server. Such tasks
    * include clearing any actor constructors added at runtime. This method
    * should be called whenever a debugger server is no longer useful, to avoid
    * memory leaks. After this method returns, the debugger server must be
    * initialized again before use.
    */
   destroy: function DS_destroy() {
     if (!this._initialized) {
       return;
     }
     for (let connID of Object.getOwnPropertyNames(this._connections)) {
       this._connections[connID].close();
     }
     for (let id of Object.getOwnPropertyNames(gRegisteredModules)) {
       let mod = gRegisteredModules[id];
       mod.module.unregister(mod.api);
     }
     gRegisteredModules = {};
     this.closeListener();
     this.globalActorFactories = {};
     this.tabActorFactories = {};
     this._allowConnection = null;
     this._transportInitialized = false;
     this._initialized = false;
     dumpn("Debugger server is shut down.");
   },
   /**
    * Load a subscript into the debugging global.
    *
    * @param aURL string A url that will be loaded as a subscript into the
    *        debugging global.  The user must load at least one script
    *        that implements a createRootActor() function to create the
    *        server's root actor.
    */
   addActors: function DS_addActors(aURL) {
     loadSubScript.call(this, aURL);
   },
   /**
    * Register a CommonJS module with the debugger server.
    * @param id string
    *    The ID of a CommonJS module.  This module must export
    *    'register' and 'unregister' functions.
    */
   registerModule: function(id) {
     if (id in gRegisteredModules) {
       throw new Error("Tried to register a module twice: " + id + "\n");
     }
     let moduleAPI = ModuleAPI();
     let mod = require(id);
     mod.register(moduleAPI);
     gRegisteredModules[id] = { module: mod, api: moduleAPI };
   },
   /**
    * Returns true if a module id has been registered.
    */
   isModuleRegistered: function(id) {
     return (id in gRegisteredModules);
   },
   /**
    * Unregister a previously-loaded CommonJS module from the debugger server.
    */
   unregisterModule: function(id) {
     let mod = gRegisteredModules[id];
     if (!mod) {
       throw new Error("Tried to unregister a module that was not previously registered.");
     }
     mod.module.unregister(mod.api);
     mod.api.destroy();
     delete gRegisteredModules[id];
   },
   /**
    * Install Firefox-specific actors.
    *
    * /!\ Be careful when adding a new actor, especially global actors.
    * Any new global actor will be exposed and returned by the root actor.
    *
    * That's the reason why tab actors aren't loaded on demand via
    * restrictPrivileges=true, to prevent exposing them on b2g parent process's
    * root actor.
    */
   addBrowserActors: function(aWindowType = "navigator:browser", restrictPrivileges = false) {
     this.chromeWindowType = aWindowType;
     this.addActors("resource://gre/modules/devtools/server/actors/webbrowser.js");
     if (!restrictPrivileges) {
       this.addTabActors();
       this.addGlobalActor(this.ChromeDebuggerActor, "chromeDebugger");
       this.registerModule("devtools/server/actors/preference");
     }
     this.addActors("resource://gre/modules/devtools/server/actors/webapps.js");
     this.registerModule("devtools/server/actors/device");
   },
   /**
    * Install tab actors in documents loaded in content childs
    */
   addChildActors: function () {
     // In case of apps being loaded in parent process, DebuggerServer is already
     // initialized and browser actors are already loaded,
     // but childtab.js hasn't been loaded yet.
     if (!DebuggerServer.tabActorFactories.hasOwnProperty("consoleActor")) {
       this.addTabActors();
     }
     // But webbrowser.js and childtab.js aren't loaded from shell.js.
     if (!("BrowserTabActor" in this)) {
       this.addActors("resource://gre/modules/devtools/server/actors/webbrowser.js");
     }
     if (!("ContentActor" in this)) {
       this.addActors("resource://gre/modules/devtools/server/actors/childtab.js");
     }
   },
   /**
    * Install tab actors.
    */
   addTabActors: function() {
     this.addActors("resource://gre/modules/devtools/server/actors/script.js");
     this.registerModule("devtools/server/actors/webconsole");
     this.registerModule("devtools/server/actors/inspector");
     this.registerModule("devtools/server/actors/call-watcher");
     this.registerModule("devtools/server/actors/canvas");
     this.registerModule("devtools/server/actors/webgl");
     this.registerModule("devtools/server/actors/webaudio");
     this.registerModule("devtools/server/actors/stylesheets");
     this.registerModule("devtools/server/actors/styleeditor");
     this.registerModule("devtools/server/actors/storage");
     this.registerModule("devtools/server/actors/gcli");
     this.registerModule("devtools/server/actors/tracer");
     this.registerModule("devtools/server/actors/memory");
     this.registerModule("devtools/server/actors/eventlooplag");
     if ("nsIProfiler" in Ci) {
       this.addActors("resource://gre/modules/devtools/server/actors/profiler.js");
     }
   },
   /**
    * Passes a set of options to the BrowserAddonActors for the given ID.
    *
    * @param aId string
    *        The ID of the add-on to pass the options to
    * @param aOptions object
    *        The options.
    * @return a promise that will be resolved when complete.
    */
   setAddonOptions: function DS_setAddonOptions(aId, aOptions) {
     if (!this._initialized) {
       return;
     }
     let promises = [];
     // Pass to all connections
     for (let connID of Object.getOwnPropertyNames(this._connections)) {
       promises.push(this._connections[connID].setAddonOptions(aId, aOptions));
     }
     return all(promises);
   },
   /**
    * Listens on the given port or socket file for remote debugger connections.
    *
    * @param aPortOrPath int, string
    *        If given an integer, the port to listen on.
    *        Otherwise, the path to the unix socket domain file to listen on.
    */
   openListener: function DS_openListener(aPortOrPath) {
     if (!Services.prefs.getBoolPref("devtools.debugger.remote-enabled")) {
       return false;
     }
     this._checkInit();
     // Return early if the server is already listening.
     if (this._listener) {
       return true;
     }
     let flags = Ci.nsIServerSocket.KeepWhenOffline;
     // A preference setting can force binding on the loopback interface.
     if (Services.prefs.getBoolPref("devtools.debugger.force-local")) {
       flags |= Ci.nsIServerSocket.LoopbackOnly;
     }
     try {
       let backlog = 4;
       let socket;
       let port = Number(aPortOrPath);
       if (port) {
         socket = new ServerSocket(port, flags, backlog);
       } else {
         let file = nsFile(aPortOrPath);
         if (file.exists())
           file.remove(false);
         socket = new UnixDomainServerSocket(file, parseInt("666", 8), backlog);
       }
       socket.asyncListen(this);
       this._listener = socket;
     } catch (e) {
       dumpn("Could not start debugging listener on '" + aPortOrPath + "': " + e);
       throw Cr.NS_ERROR_NOT_AVAILABLE;
     }
     this._socketConnections++;
     return true;
   },
   /**
    * Close a previously-opened TCP listener.
    *
    * @param aForce boolean [optional]
    *        If set to true, then the socket will be closed, regardless of the
    *        number of open connections.
    */
   closeListener: function DS_closeListener(aForce) {
     if (!this._listener || this._socketConnections == 0) {
       return false;
     }
     // Only close the listener when the last connection is closed, or if the
     // aForce flag is passed.
     if (--this._socketConnections == 0 || aForce) {
       this._listener.close();
       this._listener = null;
       this._socketConnections = 0;
     }
     return true;
   },
   /**
    * Creates a new connection to the local debugger speaking over a fake
    * transport. This connection results in straightforward calls to the onPacket
    * handlers of each side.
    *
    * @param aPrefix string [optional]
    *    If given, all actors in this connection will have names starting
    *    with |aPrefix + ':'|.
    * @returns a client-side DebuggerTransport for communicating with
    *    the newly-created connection.
    */
   connectPipe: function DS_connectPipe(aPrefix) {
     this._checkInit();
     let serverTransport = new LocalDebuggerTransport;
     let clientTransport = new LocalDebuggerTransport(serverTransport);
     serverTransport.other = clientTransport;
     let connection = this._onConnection(serverTransport, aPrefix);
     // I'm putting this here because I trust you.
     //
     // There are times, when using a local connection, when you're going
     // to be tempted to just get direct access to the server.  Resist that
     // temptation!  If you succumb to that temptation, you will make the
     // fine developers that work on Fennec and Firefox OS sad.  They're
     // professionals, they'll try to act like they understand, but deep
     // down you'll know that you hurt them.
     //
     // This reference allows you to give in to that temptation.  There are
     // times this makes sense: tests, for example, and while porting a
     // previously local-only codebase to the remote protocol.
     //
     // But every time you use this, you will feel the shame of having
     // used a property that starts with a '_'.
     clientTransport._serverConnection = connection;
     return clientTransport;
   },
   /**
    * In a content child process, create a new connection that exchanges
    * nsIMessageSender messages with our parent process.
    *
    * @param aPrefix
    *    The prefix we should use in our nsIMessageSender message names and
    *    actor names. This connection will use messages named
    *    "debug:<prefix>:packet", and all its actors will have names
    *    beginning with "<prefix>:".
    */
   connectToParent: function(aPrefix, aMessageManager) {
     this._checkInit();
     let transport = new ChildDebuggerTransport(aMessageManager, aPrefix);
     return this._onConnection(transport, aPrefix, true);
   },
   /**
    * Connect to a child process.
    *
    * @param object aConnection
    *        The debugger server connection to use.
    * @param nsIDOMElement aFrame
    *        The browser element that holds the child process.
    * @param function [aOnDisconnect]
    *        Optional function to invoke when the child is disconnected.
    * @return object
    *         A promise object that is resolved once the connection is
    *         established.
    */
   connectToChild: function(aConnection, aFrame, aOnDisconnect) {
     let deferred = defer();
     let mm = aFrame.QueryInterface(Ci.nsIFrameLoaderOwner).frameLoader
              .messageManager;
     mm.loadFrameScript("resource://gre/modules/devtools/server/child.js", false);
     let actor, childTransport;
     let prefix = aConnection.allocID("child");
     let netMonitor = null;
     let onActorCreated = DevToolsUtils.makeInfallible(function (msg) {
       mm.removeMessageListener("debug:actor", onActorCreated);
       // Pipe Debugger message from/to parent/child via the message manager
       childTransport = new ChildDebuggerTransport(mm, prefix);
       childTransport.hooks = {
         onPacket: aConnection.send.bind(aConnection),
         onClosed: function () {}
       };
       childTransport.ready();
       aConnection.setForwarding(prefix, childTransport);
       dumpn("establishing forwarding for app with prefix " + prefix);
       actor = msg.json.actor;
       netMonitor = new NetworkMonitorManager(aFrame, actor.actor);
       deferred.resolve(actor);
     }).bind(this);
     mm.addMessageListener("debug:actor", onActorCreated);
     let onMessageManagerDisconnect = DevToolsUtils.makeInfallible(function (subject, topic, data) {
       if (subject == mm) {
         Services.obs.removeObserver(onMessageManagerDisconnect, topic);
         if (childTransport) {
           // If we have a child transport, the actor has already
           // been created. We need to stop using this message manager.
           childTransport.close();
           childTransport = null;
           aConnection.cancelForwarding(prefix);
         } else {
           // Otherwise, the app has been closed before the actor
           // had a chance to be created, so we are not able to create
           // the actor.
           deferred.resolve(null);
         }
         if (actor) {
           // The ContentActor within the child process doesn't necessary
           // have to time to uninitialize itself when the app is closed/killed.
           // So ensure telling the client that the related actor is detached.
           aConnection.send({ from: actor.actor, type: "tabDetached" });
           actor = null;
         }
         if (netMonitor) {
           netMonitor.destroy();
           netMonitor = null;
         }
         if (aOnDisconnect) {
           aOnDisconnect(mm);
         }
       }
     }).bind(this);
     Services.obs.addObserver(onMessageManagerDisconnect,
                              "message-manager-disconnect", false);
     events.once(aConnection, "closed", () => {
       if (childTransport) {
         // When the client disconnects, we have to unplug the dedicated
         // ChildDebuggerTransport...
         childTransport.close();
         childTransport = null;
         aConnection.cancelForwarding(prefix);
         // ... and notify the child process to clean the tab actors.
         mm.sendAsyncMessage("debug:disconnect");
       }
       Services.obs.removeObserver(onMessageManagerDisconnect, "message-manager-disconnect");
     });
     mm.sendAsyncMessage("debug:connect", { prefix: prefix });
     return deferred.promise;
   },
   // nsIServerSocketListener implementation
   onSocketAccepted:
   DevToolsUtils.makeInfallible(function DS_onSocketAccepted(aSocket, aTransport) {
     if (Services.prefs.getBoolPref("devtools.debugger.prompt-connection") && !this._allowConnection()) {
       return;
     }
     dumpn("New debugging connection on " + aTransport.host + ":" + aTransport.port);
     let input = aTransport.openInputStream(0, 0, 0);
     let output = aTransport.openOutputStream(0, 0, 0);
     let transport = new DebuggerTransport(input, output);
     DebuggerServer._onConnection(transport);
   }, "DebuggerServer.onSocketAccepted"),
   onStopListening: function DS_onStopListening(aSocket, status) {
     dumpn("onStopListening, status: " + status);
   },
   /**
    * Raises an exception if the server has not been properly initialized.
    */
   _checkInit: function DS_checkInit() {
     if (!this._transportInitialized) {
       throw "DebuggerServer has not been initialized.";
     }
     if (!this.createRootActor) {
       throw "Use DebuggerServer.addActors() to add a root actor implementation.";
     }
   },
   /**
    * Create a new debugger connection for the given transport. Called after
    * connectPipe(), from connectToParent, or from an incoming socket
    * connection handler.
    *
    * If present, |aForwardingPrefix| is a forwarding prefix that a parent
    * server is using to recognizes messages intended for this server. Ensure
    * that all our actors have names beginning with |aForwardingPrefix + ':'|.
    * In particular, the root actor's name will be |aForwardingPrefix + ':root'|.
    */
   _onConnection: function DS_onConnection(aTransport, aForwardingPrefix, aNoRootActor = false) {
     let connID;
     if (aForwardingPrefix) {
       connID = aForwardingPrefix + ":";
     } else {
       connID = "conn" + this._nextConnID++ + '.';
     }
     let conn = new DebuggerServerConnection(connID, aTransport);
     this._connections[connID] = conn;
     // Create a root actor for the connection and send the hello packet.
     if (!aNoRootActor) {
       conn.rootActor = this.createRootActor(conn);
       if (aForwardingPrefix)
         conn.rootActor.actorID = aForwardingPrefix + ":root";
       else
         conn.rootActor.actorID = "root";
       conn.addActor(conn.rootActor);
       aTransport.send(conn.rootActor.sayHello());
     }
     aTransport.ready();
     this.emit("connectionchange", "opened", conn);
     return conn;
   },
   /**
    * Remove the connection from the debugging server.
    */
   _connectionClosed: function DS_connectionClosed(aConnection) {
     delete this._connections[aConnection.prefix];
     this.emit("connectionchange", "closed", aConnection);
   },
   // DebuggerServer extension API.
   /**
    * Registers handlers for new tab-scoped request types defined dynamically.
    * This is used for example by add-ons to augment the functionality of the tab
    * actor. Note that the name or actorPrefix of the request type is not allowed
    * to clash with existing protocol packet properties, like 'title', 'url' or
    * 'actor', since that would break the protocol.
    *
    * @param aFunction function
    *        The constructor function for this request type. This expects to be
    *        called as a constructor (i.e. with 'new'), and passed two
    *        arguments: the DebuggerServerConnection, and the BrowserTabActor
    *        with which it will be associated.
    *
    * @param aName string [optional]
    *        The name of the new request type. If this is not present, the
    *        actorPrefix property of the constructor prototype is used.
    */
   addTabActor: function DS_addTabActor(aFunction, aName) {
     let name = aName ? aName : aFunction.prototype.actorPrefix;
     if (["title", "url", "actor"].indexOf(name) != -1) {
       throw Error(name + " is not allowed");
     }
     if (DebuggerServer.tabActorFactories.hasOwnProperty(name)) {
       throw Error(name + " already exists");
     }
     DebuggerServer.tabActorFactories[name] = aFunction;
   },
   /**
    * Unregisters the handler for the specified tab-scoped request type.
    * This may be used for example by add-ons when shutting down or upgrading.
    *
    * @param aFunction function
    *        The constructor function for this request type.
    */
   removeTabActor: function DS_removeTabActor(aFunction) {
     for (let name in DebuggerServer.tabActorFactories) {
       let handler = DebuggerServer.tabActorFactories[name];
       if (handler.name == aFunction.name) {
         delete DebuggerServer.tabActorFactories[name];
       }
     }
   },
   /**
    * Registers handlers for new browser-scoped request types defined
    * dynamically. This is used for example by add-ons to augment the
    * functionality of the root actor. Note that the name or actorPrefix of the
    * request type is not allowed to clash with existing protocol packet
    * properties, like 'from', 'tabs' or 'selected', since that would break the
    * protocol.
    *
    * @param aFunction function
    *        The constructor function for this request type. This expects to be
    *        called as a constructor (i.e. with 'new'), and passed two
    *        arguments: the DebuggerServerConnection, and the BrowserRootActor
    *        with which it will be associated.
    *
    * @param aName string [optional]
    *        The name of the new request type. If this is not present, the
    *        actorPrefix property of the constructor prototype is used.
    */
   addGlobalActor: function DS_addGlobalActor(aFunction, aName) {
     let name = aName ? aName : aFunction.prototype.actorPrefix;
     if (["from", "tabs", "selected"].indexOf(name) != -1) {
       throw Error(name + " is not allowed");
     }
     if (DebuggerServer.globalActorFactories.hasOwnProperty(name)) {
       throw Error(name + " already exists");
     }
     DebuggerServer.globalActorFactories[name] = aFunction;
   },
   /**
    * Unregisters the handler for the specified browser-scoped request type.
    * This may be used for example by add-ons when shutting down or upgrading.
    *
    * @param aFunction function
    *        The constructor function for this request type.
    */
   removeGlobalActor: function DS_removeGlobalActor(aFunction) {
     for (let name in DebuggerServer.globalActorFactories) {
       let handler = DebuggerServer.globalActorFactories[name];
       if (handler.name == aFunction.name) {
         delete DebuggerServer.globalActorFactories[name];
       }
     }
   }
 };
 EventEmitter.decorate(DebuggerServer);
 if (this.exports) {
   exports.DebuggerServer = DebuggerServer;
 }
 // Needed on B2G (See header note)
 this.DebuggerServer = DebuggerServer;
 // Export ActorPool for requirers of main.js
 if (this.exports) {
   exports.ActorPool = ActorPool;
 }
 /**
  * Creates a DebuggerServerConnection.
  *
  * Represents a connection to this debugging global from a client.
  * Manages a set of actors and actor pools, allocates actor ids, and
  * handles incoming requests.
  *
  * @param aPrefix string
  *        All actor IDs created by this connection should be prefixed
  *        with aPrefix.
  * @param aTransport transport
  *        Packet transport for the debugging protocol.
  */
 function DebuggerServerConnection(aPrefix, aTransport)
 {
   this._prefix = aPrefix;
   this._transport = aTransport;
   this._transport.hooks = this;
   this._nextID = 1;
   this._actorPool = new ActorPool(this);
   this._extraPools = [];
   // Responses to a given actor must be returned the the client
   // in the same order as the requests that they're replying to, but
   // Implementations might finish serving requests in a different
   // order.  To keep things in order we generate a promise for each
   // request, chained to the promise for the request before it.
   // This map stores the latest request promise in the chain, keyed
   // by an actor ID string.
   this._actorResponses = new Map;
   /*
    * We can forward packets to other servers, if the actors on that server
    * all use a distinct prefix on their names. This is a map from prefixes
    * to transports: it maps a prefix P to a transport T if T conveys
    * packets to the server whose actors' names all begin with P + ":".
    */
   this._forwardingPrefixes = new Map;
 }
 DebuggerServerConnection.prototype = {
   _prefix: null,
   get prefix() { return this._prefix },
   _transport: null,
   get transport() { return this._transport },
   close: function() {
     this._transport.close();
   },
   send: function DSC_send(aPacket) {
     this.transport.send(aPacket);
   },
   allocID: function DSC_allocID(aPrefix) {
     return this.prefix + (aPrefix || '') + this._nextID++;
   },
   /**
    * Add a map of actor IDs to the connection.
    */
   addActorPool: function DSC_addActorPool(aActorPool) {
     this._extraPools.push(aActorPool);
   },
   /**
    * Remove a previously-added pool of actors to the connection.
    *
    * @param ActorPool aActorPool
    *        The ActorPool instance you want to remove.
    * @param boolean aNoCleanup [optional]
    *        True if you don't want to disconnect each actor from the pool, false
    *        otherwise.
    */
   removeActorPool: function DSC_removeActorPool(aActorPool, aNoCleanup) {
     let index = this._extraPools.lastIndexOf(aActorPool);
     if (index > -1) {
       let pool = this._extraPools.splice(index, 1);
       if (!aNoCleanup) {
         pool.map(function(p) { p.cleanup(); });
       }
     }
   },
   /**
    * Add an actor to the default actor pool for this connection.
    */
   addActor: function DSC_addActor(aActor) {
     this._actorPool.addActor(aActor);
   },
   /**
    * Remove an actor to the default actor pool for this connection.
    */
   removeActor: function DSC_removeActor(aActor) {
     this._actorPool.removeActor(aActor);
   },
   /**
    * Match the api expected by the protocol library.
    */
   unmanage: function(aActor) {
     return this.removeActor(aActor);
   },
   /**
    * Look up an actor implementation for an actorID.  Will search
    * all the actor pools registered with the connection.
    *
    * @param aActorID string
    *        Actor ID to look up.
    */
   getActor: function DSC_getActor(aActorID) {
     let pool = this.poolFor(aActorID);
     if (pool) {
       return pool.get(aActorID);
     }
     if (aActorID === "root") {
       return this.rootActor;
     }
     return null;
   },
   poolFor: function DSC_actorPool(aActorID) {
     if (this._actorPool && this._actorPool.has(aActorID)) {
       return this._actorPool;
     }
     for (let pool of this._extraPools) {
       if (pool.has(aActorID)) {
         return pool;
       }
     }
     return null;
   },
   _unknownError: function DSC__unknownError(aPrefix, aError) {
     let errorString = aPrefix + ": " + DevToolsUtils.safeErrorString(aError);
     Cu.reportError(errorString);
     dumpn(errorString);
     return {
       error: "unknownError",
       message: errorString
     };
   },
   /**
    * Passes a set of options to the BrowserAddonActors for the given ID.
    *
    * @param aId string
    *        The ID of the add-on to pass the options to
    * @param aOptions object
    *        The options.
    * @return a promise that will be resolved when complete.
    */
   setAddonOptions: function DSC_setAddonOptions(aId, aOptions) {
     let addonList = this.rootActor._parameters.addonList;
     if (!addonList) {
       return resolve();
     }
     return addonList.getList().then((addonActors) => {
       for (let actor of addonActors) {
         if (actor.id != aId) {
           continue;
         }
         actor.setOptions(aOptions);
         return;
       }
     });
   },
   /* Forwarding packets to other transports based on actor name prefixes. */
   /*
    * Arrange to forward packets to another server. This is how we
    * forward debugging connections to child processes.
    *
    * If we receive a packet for an actor whose name begins with |aPrefix|
    * followed by ':', then we will forward that packet to |aTransport|.
    *
    * This overrides any prior forwarding for |aPrefix|.
    *
    * @param aPrefix string
    *    The actor name prefix, not including the ':'.
    * @param aTransport object
    *    A packet transport to which we should forward packets to actors
    *    whose names begin with |(aPrefix + ':').|
    */
   setForwarding: function(aPrefix, aTransport) {
     this._forwardingPrefixes.set(aPrefix, aTransport);
   },
   /*
    * Stop forwarding messages to actors whose names begin with
    * |aPrefix+':'|. Such messages will now elicit 'noSuchActor' errors.
    */
   cancelForwarding: function(aPrefix) {
     this._forwardingPrefixes.delete(aPrefix);
   },
   // Transport hooks.
   /**
    * Called by DebuggerTransport to dispatch incoming packets as appropriate.
    *
    * @param aPacket object
    *        The incoming packet.
    */
   onPacket: function DSC_onPacket(aPacket) {
     // If the actor's name begins with a prefix we've been asked to
     // forward, do so.
     //
     // Note that the presence of a prefix alone doesn't indicate that
     // forwarding is needed: in DebuggerServerConnection instances in child
     // processes, every actor has a prefixed name.
     if (this._forwardingPrefixes.size > 0) {
       let colon = aPacket.to.indexOf(':');
       if (colon >= 0) {
         let forwardTo = this._forwardingPrefixes.get(aPacket.to.substring(0, colon));
         if (forwardTo) {
           forwardTo.send(aPacket);
           return;
         }
       }
     }
     let actor = this.getActor(aPacket.to);
     if (!actor) {
       this.transport.send({ from: aPacket.to ? aPacket.to : "root",
                             error: "noSuchActor",
                             message: "No such actor for ID: " + aPacket.to });
       return;
     }
     // Dyamically-loaded actors have to be created lazily.
     if (typeof actor == "function") {
       let instance;
       try {
         instance = new actor();
       } catch (e) {
         this.transport.send(this._unknownError(
           "Error occurred while creating actor '" + actor.name,
           e));
       }
       instance.parentID = actor.parentID;
       // We want the newly-constructed actor to completely replace the factory
       // actor. Reusing the existing actor ID will make sure ActorPool.addActor
       // does the right thing.
       instance.actorID = actor.actorID;
       actor.registeredPool.addActor(instance);
       actor = instance;
     }
     var ret = null;
     // handle "requestTypes" RDP request.
     if (aPacket.type == "requestTypes") {
       ret = { from: actor.actorID, requestTypes: Object.keys(actor.requestTypes) };
     } else if (actor.requestTypes && actor.requestTypes[aPacket.type]) {
       // Dispatch the request to the actor.
       try {
         this.currentPacket = aPacket;
         ret = actor.requestTypes[aPacket.type].bind(actor)(aPacket, this);
       } catch(e) {
         this.transport.send(this._unknownError(
           "error occurred while processing '" + aPacket.type,
           e));
       } finally {
         this.currentPacket = undefined;
       }
     } else {
       ret = { error: "unrecognizedPacketType",
               message: ('Actor "' + actor.actorID +
                         '" does not recognize the packet type "' +
                         aPacket.type + '"') };
     }
     if (!ret) {
       // This should become an error once we've converted every user
       // of this to promises in bug 794078.
       return;
     }
     let pendingResponse = this._actorResponses.get(actor.actorID) || resolve(null);
     let response = pendingResponse.then(() => {
       return ret;
     }).then(aResponse => {
       if (!aResponse.from) {
         aResponse.from = aPacket.to;
       }
       this.transport.send(aResponse);
     }).then(null, (e) => {
       let errorPacket = this._unknownError(
         "error occurred while processing '" + aPacket.type,
         e);
       errorPacket.from = aPacket.to;
       this.transport.send(errorPacket);
     });
     this._actorResponses.set(actor.actorID, response);
   },
   /**
    * Called by DebuggerTransport when the underlying stream is closed.
    *
    * @param aStatus nsresult
    *        The status code that corresponds to the reason for closing
    *        the stream.
    */
   onClosed: function DSC_onClosed(aStatus) {
     dumpn("Cleaning up connection.");
     if (!this._actorPool) {
       // Ignore this call if the connection is already closed.
       return;
     }
     events.emit(this, "closed", aStatus);
     this._actorPool.cleanup();
     this._actorPool = null;
     this._extraPools.map(function(p) { p.cleanup(); });
     this._extraPools = null;
     DebuggerServer._connectionClosed(this);
   },
   /*
    * Debugging helper for inspecting the state of the actor pools.
    */
   _dumpPools: function DSC_dumpPools() {
     dumpn("/-------------------- dumping pools:");
     if (this._actorPool) {
       dumpn("--------------------- actorPool actors: " +
             uneval(Object.keys(this._actorPool._actors)));
     }
     for each (let pool in this._extraPools)
       dumpn("--------------------- extraPool actors: " +
             uneval(Object.keys(pool._actors)));
   },
   /*
    * Debugging helper for inspecting the state of an actor pool.
    */
   _dumpPool: function DSC_dumpPools(aPool) {
     dumpn("/-------------------- dumping pool:");
     dumpn("--------------------- actorPool actors: " +
           uneval(Object.keys(aPool._actors)));
   }
 };
 /**
  * Localization convenience methods.
  */
 let L10N = {
   /**
    * L10N shortcut function.
    *
    * @param string aName
    * @return string
    */
   getStr: function L10N_getStr(aName) {
     return this.stringBundle.GetStringFromName(aName);
   }
 };
 XPCOMUtils.defineLazyGetter(L10N, "stringBundle", function() {
   return Services.strings.createBundle(DBG_STRINGS_URI);
 });