The Tor Browser / file revision

 /* -*- 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";

 const { classes: Cc, interfaces: Ci, utils: Cu } = Components;

 const DBG_STRINGS_URI = "chrome://browser/locale/devtools/debugger.properties";

 const NEW_SOURCE_IGNORED_URLS = ["debugger eval code", "self-hosted", "XStringBundle"];

 const NEW_SOURCE_DISPLAY_DELAY = 200; // ms

 const FETCH_SOURCE_RESPONSE_DELAY = 200; // ms

 const FETCH_EVENT_LISTENERS_DELAY = 200; // ms

 const FRAME_STEP_CLEAR_DELAY = 100; // ms

 const CALL_STACK_PAGE_SIZE = 25; // frames

 // The panel's window global is an EventEmitter firing the following events:

 const EVENTS = {

   // When the debugger's source editor instance finishes loading or unloading.

   EDITOR_LOADED: "Debugger:EditorLoaded",

   EDITOR_UNLOADED: "Debugger:EditorUnoaded",

   // When new sources are received from the debugger server.

   NEW_SOURCE: "Debugger:NewSource",

   SOURCES_ADDED: "Debugger:SourcesAdded",

   // When a source is shown in the source editor.

   SOURCE_SHOWN: "Debugger:EditorSourceShown",

   SOURCE_ERROR_SHOWN: "Debugger:EditorSourceErrorShown",

   // When the editor has shown a source and set the line / column position

   EDITOR_LOCATION_SET: "Debugger:EditorLocationSet",

   // When scopes, variables, properties and watch expressions are fetched and

   // displayed in the variables view.

   FETCHED_SCOPES: "Debugger:FetchedScopes",

   FETCHED_VARIABLES: "Debugger:FetchedVariables",

   FETCHED_PROPERTIES: "Debugger:FetchedProperties",

   FETCHED_BUBBLE_PROPERTIES: "Debugger:FetchedBubbleProperties",

   FETCHED_WATCH_EXPRESSIONS: "Debugger:FetchedWatchExpressions",

   // When a breakpoint has been added or removed on the debugger server.

   BREAKPOINT_ADDED: "Debugger:BreakpointAdded",

   BREAKPOINT_REMOVED: "Debugger:BreakpointRemoved",

   // When a breakpoint has been shown or hidden in the source editor.

   BREAKPOINT_SHOWN: "Debugger:BreakpointShown",

   BREAKPOINT_HIDDEN: "Debugger:BreakpointHidden",

   // When a conditional breakpoint's popup is showing or hiding.

   CONDITIONAL_BREAKPOINT_POPUP_SHOWING: "Debugger:ConditionalBreakpointPopupShowing",

   CONDITIONAL_BREAKPOINT_POPUP_HIDING: "Debugger:ConditionalBreakpointPopupHiding",

   // When event listeners are fetched or event breakpoints are updated.

   EVENT_LISTENERS_FETCHED: "Debugger:EventListenersFetched",

   EVENT_BREAKPOINTS_UPDATED: "Debugger:EventBreakpointsUpdated",

   // When a file search was performed.

   FILE_SEARCH_MATCH_FOUND: "Debugger:FileSearch:MatchFound",

   FILE_SEARCH_MATCH_NOT_FOUND: "Debugger:FileSearch:MatchNotFound",

   // When a function search was performed.

   FUNCTION_SEARCH_MATCH_FOUND: "Debugger:FunctionSearch:MatchFound",

   FUNCTION_SEARCH_MATCH_NOT_FOUND: "Debugger:FunctionSearch:MatchNotFound",

   // When a global text search was performed.

   GLOBAL_SEARCH_MATCH_FOUND: "Debugger:GlobalSearch:MatchFound",

   GLOBAL_SEARCH_MATCH_NOT_FOUND: "Debugger:GlobalSearch:MatchNotFound",

   // After the stackframes are cleared and debugger won't pause anymore.

   AFTER_FRAMES_CLEARED: "Debugger:AfterFramesCleared",

   // When the options popup is showing or hiding.

   OPTIONS_POPUP_SHOWING: "Debugger:OptionsPopupShowing",

   OPTIONS_POPUP_HIDDEN: "Debugger:OptionsPopupHidden",

   // When the widgets layout has been changed.

   LAYOUT_CHANGED: "Debugger:LayoutChanged"

 };

 // Descriptions for what a stack frame represents after the debugger pauses.

 const FRAME_TYPE = {

   NORMAL: 0,

   CONDITIONAL_BREAKPOINT_EVAL: 1,

   WATCH_EXPRESSIONS_EVAL: 2,

   PUBLIC_CLIENT_EVAL: 3

 };

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

 Cu.import("resource://gre/modules/XPCOMUtils.jsm");

 Cu.import("resource://gre/modules/devtools/event-emitter.js");

 Cu.import("resource://gre/modules/Task.jsm");

 Cu.import("resource:///modules/devtools/SimpleListWidget.jsm");

 Cu.import("resource:///modules/devtools/BreadcrumbsWidget.jsm");

 Cu.import("resource:///modules/devtools/SideMenuWidget.jsm");

 Cu.import("resource:///modules/devtools/VariablesView.jsm");

 Cu.import("resource:///modules/devtools/VariablesViewController.jsm");

 Cu.import("resource:///modules/devtools/ViewHelpers.jsm");

 const require = Cu.import("resource://gre/modules/devtools/Loader.jsm", {}).devtools.require;

 const promise = require("devtools/toolkit/deprecated-sync-thenables");

 const Editor = require("devtools/sourceeditor/editor");

 const DebuggerEditor = require("devtools/sourceeditor/debugger.js");

 const {Tooltip} = require("devtools/shared/widgets/Tooltip");

 const FastListWidget = require("devtools/shared/widgets/FastListWidget");

 XPCOMUtils.defineLazyModuleGetter(this, "Parser",

   "resource:///modules/devtools/Parser.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "devtools",

   "resource://gre/modules/devtools/Loader.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "DevToolsUtils",

   "resource://gre/modules/devtools/DevToolsUtils.jsm");

 XPCOMUtils.defineLazyModuleGetter(this, "ShortcutUtils",

   "resource://gre/modules/ShortcutUtils.jsm");

 Object.defineProperty(this, "NetworkHelper", {

   get: function() {

     return devtools.require("devtools/toolkit/webconsole/network-helper");

   },

   configurable: true,

   enumerable: true

 });

 /**

  * Object defining the debugger controller components.

  */

 let DebuggerController = {

   /**

    * Initializes the debugger controller.

    */

   initialize: function() {

     dumpn("Initializing the DebuggerController");

     this.startupDebugger = this.startupDebugger.bind(this);

     this.shutdownDebugger = this.shutdownDebugger.bind(this);

     this._onTabNavigated = this._onTabNavigated.bind(this);

     this._onTabDetached = this._onTabDetached.bind(this);

   },

   /**

    * Initializes the view.

    *

    * @return object

    *         A promise that is resolved when the debugger finishes startup.

    */

   startupDebugger: function() {

     if (this._startup) {

       return this._startup;

     }

     return this._startup = DebuggerView.initialize();

   },

   /**

    * Destroys the view and disconnects the debugger client from the server.

    *

    * @return object

    *         A promise that is resolved when the debugger finishes shutdown.

    */

   shutdownDebugger: function() {

     if (this._shutdown) {

       return this._shutdown;

     }

     return this._shutdown = DebuggerView.destroy().then(() => {

       DebuggerView.destroy();

       this.SourceScripts.disconnect();

       this.StackFrames.disconnect();

       this.ThreadState.disconnect();

       this.Tracer.disconnect();

       this.disconnect();

     });

   },

   /**

    * Initiates remote debugging based on the current target, wiring event

    * handlers as necessary.

    *

    * @return object

    *         A promise that is resolved when the debugger finishes connecting.

    */

   connect: function() {

     if (this._connection) {

       return this._connection;

     }

     let startedDebugging = promise.defer();

     this._connection = startedDebugging.promise;

     let target = this._target;

     let { client, form: { chromeDebugger, traceActor, addonActor } } = target;

     target.on("close", this._onTabDetached);

     target.on("navigate", this._onTabNavigated);

     target.on("will-navigate", this._onTabNavigated);

     this.client = client;

     if (addonActor) {

       this._startAddonDebugging(addonActor, startedDebugging.resolve);

     } else if (target.chrome) {

       this._startChromeDebugging(chromeDebugger, startedDebugging.resolve);

     } else {

       this._startDebuggingTab(startedDebugging.resolve);

       const startedTracing = promise.defer();

       if (Prefs.tracerEnabled && traceActor) {

         this._startTracingTab(traceActor, startedTracing.resolve);

       } else {

         startedTracing.resolve();

       }

       return promise.all([startedDebugging.promise, startedTracing.promise]);

     }

     return startedDebugging.promise;

   },

   /**

    * Disconnects the debugger client and removes event handlers as necessary.

    */

   disconnect: function() {

     // Return early if the client didn't even have a chance to instantiate.

     if (!this.client) {

       return;

     }

     this._connection = null;

     this.client = null;

     this.activeThread = null;

   },

   /**

    * Called for each location change in the debugged tab.

    *

    * @param string aType

    *        Packet type.

    * @param object aPacket

    *        Packet received from the server.

    */

   _onTabNavigated: function(aType, aPacket) {

     switch (aType) {

       case "will-navigate": {

         // Reset UI.

         DebuggerView.handleTabNavigation();

         // Discard all the cached sources *before* the target starts navigating.

         // Sources may be fetched during navigation, in which case we don't

         // want to hang on to the old source contents.

         DebuggerController.SourceScripts.clearCache();

         DebuggerController.Parser.clearCache();

         SourceUtils.clearCache();

         // Prevent performing any actions that were scheduled before navigation.

         clearNamedTimeout("new-source");

         clearNamedTimeout("event-breakpoints-update");

         clearNamedTimeout("event-listeners-fetch");

         break;

       }

       case "navigate": {

         this.ThreadState.handleTabNavigation();

         this.StackFrames.handleTabNavigation();

         this.SourceScripts.handleTabNavigation();

         break;

       }

     }

   },

   /**

    * Called when the debugged tab is closed.

    */

   _onTabDetached: function() {

     this.shutdownDebugger();

   },

   /**

    * Warn if resuming execution produced a wrongOrder error.

    */

   _ensureResumptionOrder: function(aResponse) {

     if (aResponse.error == "wrongOrder") {

       DebuggerView.Toolbar.showResumeWarning(aResponse.lastPausedUrl);

     }

   },

   /**

    * Sets up a debugging session.

    *

    * @param function aCallback

    *        A function to invoke once the client attaches to the active thread.

    */

   _startDebuggingTab: function(aCallback) {

     this._target.activeTab.attachThread({

       useSourceMaps: Prefs.sourceMapsEnabled

     }, (aResponse, aThreadClient) => {

       if (!aThreadClient) {

         Cu.reportError("Couldn't attach to thread: " + aResponse.error);

         return;

       }

       this.activeThread = aThreadClient;

       this.ThreadState.connect();

       this.StackFrames.connect();

       this.SourceScripts.connect();

       if (aThreadClient.paused) {

         aThreadClient.resume(this._ensureResumptionOrder);

       }

       if (aCallback) {

         aCallback();

       }

     });

   },

   /**

    * Sets up an addon debugging session.

    *

    * @param object aAddonActor

    *        The actor for the addon that is being debugged.

    * @param function aCallback

    *        A function to invoke once the client attaches to the active thread.

    */

   _startAddonDebugging: function(aAddonActor, aCallback) {

     this.client.attachAddon(aAddonActor, (aResponse) => {

       return this._startChromeDebugging(aResponse.threadActor, aCallback);

     });

   },

   /**

    * Sets up a chrome debugging session.

    *

    * @param object aChromeDebugger

    *        The remote protocol grip of the chrome debugger.

    * @param function aCallback

    *        A function to invoke once the client attaches to the active thread.

    */

   _startChromeDebugging: function(aChromeDebugger, aCallback) {

     this.client.attachThread(aChromeDebugger, (aResponse, aThreadClient) => {

       if (!aThreadClient) {

         Cu.reportError("Couldn't attach to thread: " + aResponse.error);

         return;

       }

       this.activeThread = aThreadClient;

       this.ThreadState.connect();

       this.StackFrames.connect();

       this.SourceScripts.connect();

       if (aThreadClient.paused) {

         aThreadClient.resume(this._ensureResumptionOrder);

       }

       if (aCallback) {

         aCallback();

       }

     }, { useSourceMaps: Prefs.sourceMapsEnabled });

   },

   /**

    * Sets up an execution tracing session.

    *

    * @param object aTraceActor

    *        The remote protocol grip of the trace actor.

    * @param function aCallback

    *        A function to invoke once the client attaches to the tracer.

    */

   _startTracingTab: function(aTraceActor, aCallback) {

     this.client.attachTracer(aTraceActor, (response, traceClient) => {

       if (!traceClient) {

         DevToolsUtils.reportException("DebuggerController._startTracingTab",

                                       new Error("Failed to attach to tracing actor."));

         return;

       }

       this.traceClient = traceClient;

       this.Tracer.connect();

       if (aCallback) {

         aCallback();

       }

     });

   },

   /**

    * Detach and reattach to the thread actor with useSourceMaps true, blow

    * away old sources and get them again.

    */

   reconfigureThread: function(aUseSourceMaps) {

     this.activeThread.reconfigure({ useSourceMaps: aUseSourceMaps }, aResponse => {

       if (aResponse.error) {

         let msg = "Couldn't reconfigure thread: " + aResponse.message;

         Cu.reportError(msg);

         dumpn(msg);

         return;

       }

       // Reset the view and fetch all the sources again.

       DebuggerView.handleTabNavigation();

       this.SourceScripts.handleTabNavigation();

       // Update the stack frame list.

       if (this.activeThread.paused) {

         this.activeThread._clearFrames();

         this.activeThread.fillFrames(CALL_STACK_PAGE_SIZE);

       }

     });

   },

   _startup: null,

   _shutdown: null,

   _connection: null,

   client: null,

   activeThread: null

 };

 /**

  * ThreadState keeps the UI up to date with the state of the

  * thread (paused/attached/etc.).

  */

 function ThreadState() {

   this._update = this._update.bind(this);

 }

 ThreadState.prototype = {

   get activeThread() DebuggerController.activeThread,

   /**

    * Connect to the current thread client.

    */

   connect: function() {

     dumpn("ThreadState is connecting...");

     this.activeThread.addListener("paused", this._update);

     this.activeThread.addListener("resumed", this._update);

     this.activeThread.pauseOnExceptions(Prefs.pauseOnExceptions,

                                         Prefs.ignoreCaughtExceptions);

     this.handleTabNavigation();

   },

   /**

    * Disconnect from the client.

    */

   disconnect: function() {

     if (!this.activeThread) {

       return;

     }

     dumpn("ThreadState is disconnecting...");

     this.activeThread.removeListener("paused", this._update);

     this.activeThread.removeListener("resumed", this._update);

   },

   /**

    * Handles any initialization on a tab navigation event issued by the client.

    */

   handleTabNavigation: function() {

     if (!this.activeThread) {

       return;

     }

     dumpn("Handling tab navigation in the ThreadState");

     this._update();

   },

   /**

    * Update the UI after a thread state change.

    */

   _update: function(aEvent) {

     DebuggerView.Toolbar.toggleResumeButtonState(this.activeThread.state);

     if (gTarget && (aEvent == "paused" || aEvent == "resumed")) {

       gTarget.emit("thread-" + aEvent);

     }

   }

 };

 /**

  * Keeps the stack frame list up-to-date, using the thread client's

  * stack frame cache.

  */

 function StackFrames() {

   this._onPaused = this._onPaused.bind(this);

   this._onResumed = this._onResumed.bind(this);

   this._onFrames = this._onFrames.bind(this);

   this._onFramesCleared = this._onFramesCleared.bind(this);

   this._onBlackBoxChange = this._onBlackBoxChange.bind(this);

   this._onPrettyPrintChange = this._onPrettyPrintChange.bind(this);

   this._afterFramesCleared = this._afterFramesCleared.bind(this);

   this.evaluate = this.evaluate.bind(this);

 }

 StackFrames.prototype = {

   get activeThread() DebuggerController.activeThread,

   currentFrameDepth: -1,

   _currentFrameDescription: FRAME_TYPE.NORMAL,

   _syncedWatchExpressions: null,

   _currentWatchExpressions: null,

   _currentBreakpointLocation: null,

   _currentEvaluation: null,

   _currentException: null,

   _currentReturnedValue: null,

   /**

    * Connect to the current thread client.

    */

   connect: function() {

     dumpn("StackFrames is connecting...");

     this.activeThread.addListener("paused", this._onPaused);

     this.activeThread.addListener("resumed", this._onResumed);

     this.activeThread.addListener("framesadded", this._onFrames);

     this.activeThread.addListener("framescleared", this._onFramesCleared);

     this.activeThread.addListener("blackboxchange", this._onBlackBoxChange);

     this.activeThread.addListener("prettyprintchange", this._onPrettyPrintChange);

     this.handleTabNavigation();

   },

   /**

    * Disconnect from the client.

    */

   disconnect: function() {

     if (!this.activeThread) {

       return;

     }

     dumpn("StackFrames is disconnecting...");

     this.activeThread.removeListener("paused", this._onPaused);

     this.activeThread.removeListener("resumed", this._onResumed);

     this.activeThread.removeListener("framesadded", this._onFrames);

     this.activeThread.removeListener("framescleared", this._onFramesCleared);

     this.activeThread.removeListener("blackboxchange", this._onBlackBoxChange);

     this.activeThread.removeListener("prettyprintchange", this._onPrettyPrintChange);

     clearNamedTimeout("frames-cleared");

   },

   /**

    * Handles any initialization on a tab navigation event issued by the client.

    */

   handleTabNavigation: function() {

     dumpn("Handling tab navigation in the StackFrames");

     // Nothing to do here yet.

   },

   /**

    * Handler for the thread client's paused notification.

    *

    * @param string aEvent

    *        The name of the notification ("paused" in this case).

    * @param object aPacket

    *        The response packet.

    */

   _onPaused: function(aEvent, aPacket) {

     switch (aPacket.why.type) {

       // If paused by a breakpoint, store the breakpoint location.

       case "breakpoint":

         this._currentBreakpointLocation = aPacket.frame.where;

         break;

       // If paused by a client evaluation, store the evaluated value.

       case "clientEvaluated":

         this._currentEvaluation = aPacket.why.frameFinished;

         break;

       // If paused by an exception, store the exception value.

       case "exception":

         this._currentException = aPacket.why.exception;

         break;

       // If paused while stepping out of a frame, store the returned value or

       // thrown exception.

       case "resumeLimit":

         if (!aPacket.why.frameFinished) {

           break;

         } else if (aPacket.why.frameFinished.throw) {

           this._currentException = aPacket.why.frameFinished.throw;

         } else if (aPacket.why.frameFinished.return) {

           this._currentReturnedValue = aPacket.why.frameFinished.return;

         }

         break;

     }

     this.activeThread.fillFrames(CALL_STACK_PAGE_SIZE);

     DebuggerView.editor.focus();

   },

   /**

    * Handler for the thread client's resumed notification.

    */

   _onResumed: function() {

     // Prepare the watch expression evaluation string for the next pause.

     if (this._currentFrameDescription != FRAME_TYPE.WATCH_EXPRESSIONS_EVAL) {

       this._currentWatchExpressions = this._syncedWatchExpressions;

     }

   },

   /**

    * Handler for the thread client's framesadded notification.

    */

   _onFrames: function() {

     // Ignore useless notifications.

     if (!this.activeThread || !this.activeThread.cachedFrames.length) {

       return;

     }

     let waitForNextPause = false;

     let breakLocation = this._currentBreakpointLocation;

     let watchExpressions = this._currentWatchExpressions;

     let client = DebuggerController.activeThread.client;

     // We moved conditional breakpoint handling to the server, but

     // need to support it in the client for a while until most of the

     // server code in production is updated with it. bug 990137 is

     // filed to mark this code to be removed.

     if (!client.mainRoot.traits.conditionalBreakpoints) {

       // Conditional breakpoints are { breakpoint, expression } tuples. The

       // boolean evaluation of the expression decides if the active thread

       // automatically resumes execution or not.

       if (breakLocation) {

         // Make sure a breakpoint actually exists at the specified url and line.

         let breakpointPromise = DebuggerController.Breakpoints._getAdded(breakLocation);

         if (breakpointPromise) {

           breakpointPromise.then(({ conditionalExpression: e }) => { if (e) {

             // Evaluating the current breakpoint's conditional expression will

             // cause the stack frames to be cleared and active thread to pause,

             // sending a 'clientEvaluated' packed and adding the frames again.

             this.evaluate(e, { depth: 0, meta: FRAME_TYPE.CONDITIONAL_BREAKPOINT_EVAL });

             waitForNextPause = true;

           }});

         }

       }

       // We'll get our evaluation of the current breakpoint's conditional

       // expression the next time the thread client pauses...

       if (waitForNextPause) {

         return;

       }

       if (this._currentFrameDescription == FRAME_TYPE.CONDITIONAL_BREAKPOINT_EVAL) {

         this._currentFrameDescription = FRAME_TYPE.NORMAL;

         // If the breakpoint's conditional expression evaluation is falsy,

         // automatically resume execution.

         if (VariablesView.isFalsy({ value: this._currentEvaluation.return })) {

           this.activeThread.resume(DebuggerController._ensureResumptionOrder);

           return;

         }

       }

     }

     // Watch expressions are evaluated in the context of the topmost frame,

     // and the results are displayed in the variables view.

     // TODO: handle all of this server-side: Bug 832470, comment 14.

     if (watchExpressions) {

       // Evaluation causes the stack frames to be cleared and active thread to

       // pause, sending a 'clientEvaluated' packet and adding the frames again.

       this.evaluate(watchExpressions, { depth: 0, meta: FRAME_TYPE.WATCH_EXPRESSIONS_EVAL });

       waitForNextPause = true;

     }

     // We'll get our evaluation of the current watch expressions the next time

     // the thread client pauses...

     if (waitForNextPause) {

       return;

     }

     if (this._currentFrameDescription == FRAME_TYPE.WATCH_EXPRESSIONS_EVAL) {

       this._currentFrameDescription = FRAME_TYPE.NORMAL;

       // If an error was thrown during the evaluation of the watch expressions,

       // then at least one expression evaluation could not be performed. So

       // remove the most recent watch expression and try again.

       if (this._currentEvaluation.throw) {

         DebuggerView.WatchExpressions.removeAt(0);

         DebuggerController.StackFrames.syncWatchExpressions();

         return;

       }

     }

     // Make sure the debugger view panes are visible, then refill the frames.

     DebuggerView.showInstrumentsPane();

     this._refillFrames();

     // No additional processing is necessary for this stack frame.

     if (this._currentFrameDescription != FRAME_TYPE.NORMAL) {

       this._currentFrameDescription = FRAME_TYPE.NORMAL;

     }

   },

   /**

    * Fill the StackFrames view with the frames we have in the cache, compressing

    * frames which have black boxed sources into single frames.

    */

   _refillFrames: function() {

     // Make sure all the previous stackframes are removed before re-adding them.

     DebuggerView.StackFrames.empty();

     for (let frame of this.activeThread.cachedFrames) {

       let { depth, where: { url, line }, source } = frame;

       let isBlackBoxed = source ? this.activeThread.source(source).isBlackBoxed : false;

       let location = NetworkHelper.convertToUnicode(unescape(url));

       let title = StackFrameUtils.getFrameTitle(frame);

       DebuggerView.StackFrames.addFrame(title, location, line, depth, isBlackBoxed);

     }

     DebuggerView.StackFrames.selectedDepth = Math.max(this.currentFrameDepth, 0);

     DebuggerView.StackFrames.dirty = this.activeThread.moreFrames;

   },

   /**

    * Handler for the thread client's framescleared notification.

    */

   _onFramesCleared: function() {

     switch (this._currentFrameDescription) {

       case FRAME_TYPE.NORMAL:

         this._currentEvaluation = null;

         this._currentException = null;

         this._currentReturnedValue = null;

         break;

       case FRAME_TYPE.CONDITIONAL_BREAKPOINT_EVAL:

         this._currentBreakpointLocation = null;

         break;

       case FRAME_TYPE.WATCH_EXPRESSIONS_EVAL:

         this._currentWatchExpressions = null;

         break;

     }

     // After each frame step (in, over, out), framescleared is fired, which

     // forces the UI to be emptied and rebuilt on framesadded. Most of the times

     // this is not necessary, and will result in a brief redraw flicker.

     // To avoid it, invalidate the UI only after a short time if necessary.

     setNamedTimeout("frames-cleared", FRAME_STEP_CLEAR_DELAY, this._afterFramesCleared);

   },

   /**

    * Handler for the debugger's blackboxchange notification.

    */

   _onBlackBoxChange: function() {

     if (this.activeThread.state == "paused") {

       // Hack to avoid selecting the topmost frame after blackboxing a source.

       this.currentFrameDepth = NaN;

       this._refillFrames();

     }

   },

   /**

    * Handler for the debugger's prettyprintchange notification.

    */

   _onPrettyPrintChange: function() {

     // Makes sure the selected source remains selected

     // after the fillFrames is called.

     const source = DebuggerView.Sources.selectedValue;

     if (this.activeThread.state == "paused") {

       this.activeThread.fillFrames(

          CALL_STACK_PAGE_SIZE,

          () => DebuggerView.Sources.selectedValue = source);

     }

   },

   /**

    * Called soon after the thread client's framescleared notification.

    */

   _afterFramesCleared: function() {

     // Ignore useless notifications.

     if (this.activeThread.cachedFrames.length) {

       return;

     }

     DebuggerView.editor.clearDebugLocation();

     DebuggerView.StackFrames.empty();

     DebuggerView.Sources.unhighlightBreakpoint();

     DebuggerView.WatchExpressions.toggleContents(true);

     DebuggerView.Variables.empty(0);

     window.emit(EVENTS.AFTER_FRAMES_CLEARED);

   },

   /**

    * Marks the stack frame at the specified depth as selected and updates the

    * properties view with the stack frame's data.

    *

    * @param number aDepth

    *        The depth of the frame in the stack.

    */

   selectFrame: function(aDepth) {

     // Make sure the frame at the specified depth exists first.

     let frame = this.activeThread.cachedFrames[this.currentFrameDepth = aDepth];

     if (!frame) {

       return;

     }

     // Check if the frame does not represent the evaluation of debuggee code.

     let { environment, where } = frame;

     if (!environment) {

       return;

     }

     // Don't change the editor's location if the execution was paused by a

     // public client evaluation. This is useful for adding overlays on

     // top of the editor, like a variable inspection popup.

     let isClientEval = this._currentFrameDescription == FRAME_TYPE.PUBLIC_CLIENT_EVAL;

     let isPopupShown = DebuggerView.VariableBubble.contentsShown();

     if (!isClientEval && !isPopupShown) {

       // Move the editor's caret to the proper url and line.

       DebuggerView.setEditorLocation(where.url, where.line);

       // Highlight the breakpoint at the specified url and line if it exists.

       DebuggerView.Sources.highlightBreakpoint(where, { noEditorUpdate: true });

     }

     // Don't display the watch expressions textbox inputs in the pane.

     DebuggerView.WatchExpressions.toggleContents(false);

     // Start recording any added variables or properties in any scope and

     // clear existing scopes to create each one dynamically.

     DebuggerView.Variables.empty();

     // If watch expressions evaluation results are available, create a scope

     // to contain all the values.

     if (this._syncedWatchExpressions && aDepth == 0) {

       let label = L10N.getStr("watchExpressionsScopeLabel");

       let scope = DebuggerView.Variables.addScope(label);

       // Customize the scope for holding watch expressions evaluations.

       scope.descriptorTooltip = false;

       scope.contextMenuId = "debuggerWatchExpressionsContextMenu";

       scope.separatorStr = L10N.getStr("watchExpressionsSeparatorLabel");

       scope.switch = DebuggerView.WatchExpressions.switchExpression;

       scope.delete = DebuggerView.WatchExpressions.deleteExpression;

       // The evaluation hasn't thrown, so fetch and add the returned results.

       this._fetchWatchExpressions(scope, this._currentEvaluation.return);

       // The watch expressions scope is always automatically expanded.

       scope.expand();

     }

     do {

       // Create a scope to contain all the inspected variables in the

       // current environment.

       let label = StackFrameUtils.getScopeLabel(environment);

       let scope = DebuggerView.Variables.addScope(label);

       let innermost = environment == frame.environment;

       // Handle special additions to the innermost scope.

       if (innermost) {

         this._insertScopeFrameReferences(scope, frame);

       }

       // Handle the expansion of the scope, lazily populating it with the

       // variables in the current environment.

       DebuggerView.Variables.controller.addExpander(scope, environment);

       // The innermost scope is always automatically expanded, because it

       // contains the variables in the current stack frame which are likely to

       // be inspected.

       if (innermost) {

         scope.expand();

       }

     } while ((environment = environment.parent));

     // Signal that scope environments have been shown.

     window.emit(EVENTS.FETCHED_SCOPES);

   },

   /**

    * Loads more stack frames from the debugger server cache.

    */

   addMoreFrames: function() {

     this.activeThread.fillFrames(

       this.activeThread.cachedFrames.length + CALL_STACK_PAGE_SIZE);

   },

   /**

    * Evaluate an expression in the context of the selected frame.

    *

    * @param string aExpression

    *        The expression to evaluate.

    * @param object aOptions [optional]

    *        Additional options for this client evaluation:

    *          - depth: the frame depth used for evaluation, 0 being the topmost.

    *          - meta: some meta-description for what this evaluation represents.

    * @return object

    *         A promise that is resolved when the evaluation finishes,

    *         or rejected if there was no stack frame available or some

    *         other error occurred.

    */

   evaluate: function(aExpression, aOptions = {}) {

     let depth = "depth" in aOptions ? aOptions.depth : this.currentFrameDepth;

     let frame = this.activeThread.cachedFrames[depth];

     if (frame == null) {

       return promise.reject(new Error("No stack frame available."));

     }

     let deferred = promise.defer();

     this.activeThread.addOneTimeListener("paused", (aEvent, aPacket) => {

       let { type, frameFinished } = aPacket.why;

       if (type == "clientEvaluated") {

         if (!("terminated" in frameFinished)) {

           deferred.resolve(frameFinished);

         } else {

           deferred.reject(new Error("The execution was abruptly terminated."));

         }

       } else {

         deferred.reject(new Error("Active thread paused unexpectedly."));

       }

     });

     let meta = "meta" in aOptions ? aOptions.meta : FRAME_TYPE.PUBLIC_CLIENT_EVAL;

     this._currentFrameDescription = meta;

     this.activeThread.eval(frame.actor, aExpression);

     return deferred.promise;

   },

   /**

    * Add nodes for special frame references in the innermost scope.

    *

    * @param Scope aScope

    *        The scope where the references will be placed into.

    * @param object aFrame

    *        The frame to get some references from.

    */

   _insertScopeFrameReferences: function(aScope, aFrame) {

     // Add any thrown exception.

     if (this._currentException) {

       let excRef = aScope.addItem("<exception>", { value: this._currentException });

       DebuggerView.Variables.controller.addExpander(excRef, this._currentException);

     }

     // Add any returned value.

     if (this._currentReturnedValue) {

       let retRef = aScope.addItem("<return>", { value: this._currentReturnedValue });

       DebuggerView.Variables.controller.addExpander(retRef, this._currentReturnedValue);

     }

     // Add "this".

     if (aFrame.this) {

       let thisRef = aScope.addItem("this", { value: aFrame.this });

       DebuggerView.Variables.controller.addExpander(thisRef, aFrame.this);

     }

   },

   /**

    * Adds the watch expressions evaluation results to a scope in the view.

    *

    * @param Scope aScope

    *        The scope where the watch expressions will be placed into.

    * @param object aExp

    *        The grip of the evaluation results.

    */

   _fetchWatchExpressions: function(aScope, aExp) {

     // Fetch the expressions only once.

     if (aScope._fetched) {

       return;

     }

     aScope._fetched = true;

     // Add nodes for every watch expression in scope.

     this.activeThread.pauseGrip(aExp).getPrototypeAndProperties(aResponse => {

       let ownProperties = aResponse.ownProperties;

       let totalExpressions = DebuggerView.WatchExpressions.itemCount;

       for (let i = 0; i < totalExpressions; i++) {

         let name = DebuggerView.WatchExpressions.getString(i);

         let expVal = ownProperties[i].value;

         let expRef = aScope.addItem(name, ownProperties[i]);

         DebuggerView.Variables.controller.addExpander(expRef, expVal);

         // Revert some of the custom watch expressions scope presentation flags,

         // so that they don't propagate to child items.

         expRef.switch = null;

         expRef.delete = null;

         expRef.descriptorTooltip = true;

         expRef.separatorStr = L10N.getStr("variablesSeparatorLabel");

       }

       // Signal that watch expressions have been fetched.

       window.emit(EVENTS.FETCHED_WATCH_EXPRESSIONS);

     });

   },

   /**

    * Updates a list of watch expressions to evaluate on each pause.

    * TODO: handle all of this server-side: Bug 832470, comment 14.

    */

   syncWatchExpressions: function() {

     let list = DebuggerView.WatchExpressions.getAllStrings();

     // Sanity check all watch expressions before syncing them. To avoid

     // having the whole watch expressions array throw because of a single

     // faulty expression, simply convert it to a string describing the error.

     // There's no other information necessary to be offered in such cases.

     let sanitizedExpressions = list.map(aString => {

       // Reflect.parse throws when it encounters a syntax error.

       try {

         Parser.reflectionAPI.parse(aString);

         return aString; // Watch expression can be executed safely.

       } catch (e) {

         return "\"" + e.name + ": " + e.message + "\""; // Syntax error.

       }

     });

     if (sanitizedExpressions.length) {

       this._syncedWatchExpressions =

         this._currentWatchExpressions =

           "[" +

             sanitizedExpressions.map(aString =>

               "eval(\"" +

                 "try {" +

                   // Make sure all quotes are escaped in the expression's syntax,

                   // and add a newline after the statement to avoid comments

                   // breaking the code integrity inside the eval block.

                   aString.replace(/"/g, "\\$&") + "\" + " + "'\\n'" + " + \"" +

                 "} catch (e) {" +

                   "e.name + ': ' + e.message;" + // TODO: Bug 812765, 812764.

                 "}" +

               "\")"

             ).join(",") +

           "]";

     } else {

       this._syncedWatchExpressions =

         this._currentWatchExpressions = null;

     }

     this.currentFrameDepth = -1;

     this._onFrames();

   }

 };

 /**

  * Keeps the source script list up-to-date, using the thread client's

  * source script cache.

  */

 function SourceScripts() {

   this._onNewGlobal = this._onNewGlobal.bind(this);

   this._onNewSource = this._onNewSource.bind(this);

   this._onSourcesAdded = this._onSourcesAdded.bind(this);

   this._onBlackBoxChange = this._onBlackBoxChange.bind(this);

   this._onPrettyPrintChange = this._onPrettyPrintChange.bind(this);

 }

 SourceScripts.prototype = {

   get activeThread() DebuggerController.activeThread,

   get debuggerClient() DebuggerController.client,

   _cache: new Map(),

   /**

    * Connect to the current thread client.

    */

   connect: function() {

     dumpn("SourceScripts is connecting...");

     this.debuggerClient.addListener("newGlobal", this._onNewGlobal);

     this.debuggerClient.addListener("newSource", this._onNewSource);

     this.activeThread.addListener("blackboxchange", this._onBlackBoxChange);

     this.activeThread.addListener("prettyprintchange", this._onPrettyPrintChange);

     this.handleTabNavigation();

   },

   /**

    * Disconnect from the client.

    */

   disconnect: function() {

     if (!this.activeThread) {

       return;

     }

     dumpn("SourceScripts is disconnecting...");

     this.debuggerClient.removeListener("newGlobal", this._onNewGlobal);

     this.debuggerClient.removeListener("newSource", this._onNewSource);

     this.activeThread.removeListener("blackboxchange", this._onBlackBoxChange);

     this.activeThread.addListener("prettyprintchange", this._onPrettyPrintChange);

   },

   /**

    * Clears all the cached source contents.

    */

   clearCache: function() {

     this._cache.clear();

   },

   /**

    * Handles any initialization on a tab navigation event issued by the client.

    */

   handleTabNavigation: function() {

     if (!this.activeThread) {

       return;

     }

     dumpn("Handling tab navigation in the SourceScripts");

     // Retrieve the list of script sources known to the server from before

     // the client was ready to handle "newSource" notifications.

     this.activeThread.getSources(this._onSourcesAdded);

   },

   /**

    * Handler for the debugger client's unsolicited newGlobal notification.

    */

   _onNewGlobal: function(aNotification, aPacket) {

     // TODO: bug 806775, update the globals list using aPacket.hostAnnotations

     // from bug 801084.

   },

   /**

    * Handler for the debugger client's unsolicited newSource notification.

    */

   _onNewSource: function(aNotification, aPacket) {

     // Ignore bogus scripts, e.g. generated from 'clientEvaluate' packets.

     if (NEW_SOURCE_IGNORED_URLS.indexOf(aPacket.source.url) != -1) {

       return;

     }

     // Add the source in the debugger view sources container.

     DebuggerView.Sources.addSource(aPacket.source, { staged: false });

     // Select this source if it's the preferred one.

     let preferredValue = DebuggerView.Sources.preferredValue;

     if (aPacket.source.url == preferredValue) {

       DebuggerView.Sources.selectedValue = preferredValue;

     }

     // ..or the first entry if there's none selected yet after a while

     else {

       setNamedTimeout("new-source", NEW_SOURCE_DISPLAY_DELAY, () => {

         // If after a certain delay the preferred source still wasn't received,

         // just give up on waiting and display the first entry.

         if (!DebuggerView.Sources.selectedValue) {

           DebuggerView.Sources.selectedIndex = 0;

         }

       });

     }

     // If there are any stored breakpoints for this source, display them again,

     // both in the editor and the breakpoints pane.

     DebuggerController.Breakpoints.updateEditorBreakpoints();

     DebuggerController.Breakpoints.updatePaneBreakpoints();

     // Make sure the events listeners are up to date.

     if (DebuggerView.instrumentsPaneTab == "events-tab") {

       DebuggerController.Breakpoints.DOM.scheduleEventListenersFetch();

     }

     // Signal that a new source has been added.

     window.emit(EVENTS.NEW_SOURCE);

   },

   /**

    * Callback for the debugger's active thread getSources() method.

    */

   _onSourcesAdded: function(aResponse) {

     if (aResponse.error) {

       let msg = "Error getting sources: " + aResponse.message;

       Cu.reportError(msg);

       dumpn(msg);

       return;

     }

     if (aResponse.sources.length === 0) {

       DebuggerView.Sources.emptyText = L10N.getStr("noSourcesText");

       window.emit(EVENTS.SOURCES_ADDED);

       return;

     }

     // Add all the sources in the debugger view sources container.

     for (let source of aResponse.sources) {

       // Ignore bogus scripts, e.g. generated from 'clientEvaluate' packets.

       if (NEW_SOURCE_IGNORED_URLS.indexOf(source.url) == -1) {

         DebuggerView.Sources.addSource(source, { staged: true });

       }

     }

     // Flushes all the prepared sources into the sources container.

     DebuggerView.Sources.commit({ sorted: true });

     // Select the preferred source if it exists and was part of the response.

     let preferredValue = DebuggerView.Sources.preferredValue;

     if (DebuggerView.Sources.containsValue(preferredValue)) {

       DebuggerView.Sources.selectedValue = preferredValue;

     }

     // ..or the first entry if there's no one selected yet.

     else if (!DebuggerView.Sources.selectedValue) {

       DebuggerView.Sources.selectedIndex = 0;

     }

     // If there are any stored breakpoints for the sources, display them again,

     // both in the editor and the breakpoints pane.

     DebuggerController.Breakpoints.updateEditorBreakpoints();

     DebuggerController.Breakpoints.updatePaneBreakpoints();

     // Signal that sources have been added.

     window.emit(EVENTS.SOURCES_ADDED);

   },

   /**

    * Handler for the debugger client's 'blackboxchange' notification.

    */

   _onBlackBoxChange: function (aEvent, { url, isBlackBoxed }) {

     const item = DebuggerView.Sources.getItemByValue(url);

     if (item) {

       if (isBlackBoxed) {

         item.target.classList.add("black-boxed");

       } else {

         item.target.classList.remove("black-boxed");

       }

     }

     DebuggerView.Sources.updateToolbarButtonsState();

     DebuggerView.maybeShowBlackBoxMessage();

   },

   /**

    * Set the black boxed status of the given source.

    *

    * @param Object aSource

    *        The source form.

    * @param bool aBlackBoxFlag

    *        True to black box the source, false to un-black box it.

    * @returns Promise

    *          A promize that resolves to [aSource, isBlackBoxed] or rejects to

    *          [aSource, error].

    */

   setBlackBoxing: function(aSource, aBlackBoxFlag) {

     const sourceClient = this.activeThread.source(aSource);

     const deferred = promise.defer();

     sourceClient[aBlackBoxFlag ? "blackBox" : "unblackBox"](aPacket => {

       const { error, message } = aPacket;

       if (error) {

         let msg = "Couldn't toggle black boxing for " + aSource.url + ": " + message;

         dumpn(msg);

         Cu.reportError(msg);

         deferred.reject([aSource, msg]);

       } else {

         deferred.resolve([aSource, sourceClient.isBlackBoxed]);

       }

     });

     return deferred.promise;

   },

   /**

    * Toggle the pretty printing of a source's text. All subsequent calls to

    * |getText| will return the pretty-toggled text. Nothing will happen for

    * non-javascript files.

    *

    * @param Object aSource

    *        The source form from the RDP.

    * @returns Promise

    *          A promise that resolves to [aSource, prettyText] or rejects to

    *          [aSource, error].

    */

   togglePrettyPrint: function(aSource) {

     // Only attempt to pretty print JavaScript sources.

     if (!SourceUtils.isJavaScript(aSource.url, aSource.contentType)) {

       return promise.reject([aSource, "Can't prettify non-javascript files."]);

     }

     const sourceClient = this.activeThread.source(aSource);

     const wantPretty = !sourceClient.isPrettyPrinted;

     // Only use the existing promise if it is pretty printed.

     let textPromise = this._cache.get(aSource.url);

     if (textPromise && textPromise.pretty === wantPretty) {

       return textPromise;

     }

     const deferred = promise.defer();

     deferred.promise.pretty = wantPretty;

     this._cache.set(aSource.url, deferred.promise);

     const afterToggle = ({ error, message, source: text, contentType }) => {

       if (error) {

         // Revert the rejected promise from the cache, so that the original

         // source's text may be shown when the source is selected.

         this._cache.set(aSource.url, textPromise);

         deferred.reject([aSource, message || error]);

         return;

       }

       deferred.resolve([aSource, text, contentType]);

     };

     if (wantPretty) {

       sourceClient.prettyPrint(Prefs.editorTabSize, afterToggle);

     } else {

       sourceClient.disablePrettyPrint(afterToggle);

     }

     return deferred.promise;

   },

   /**

    * Handler for the debugger's prettyprintchange notification.

    */

   _onPrettyPrintChange: function(aEvent, { url }) {

     // Remove the cached source AST from the Parser, to avoid getting

     // wrong locations when searching for functions.

     DebuggerController.Parser.clearSource(url);

   },

   /**

    * Gets a specified source's text.

    *

    * @param object aSource

    *        The source object coming from the active thread.

    * @param function aOnTimeout [optional]

    *        Function called when the source text takes a long time to fetch,

    *        but not necessarily failing. Long fetch times don't cause the

    *        rejection of the returned promise.

    * @param number aDelay [optional]

    *        The amount of time it takes to consider a source slow to fetch.

    *        If unspecified, it defaults to a predefined value.

    * @return object

    *         A promise that is resolved after the source text has been fetched.

    */

   getText: function(aSource, aOnTimeout, aDelay = FETCH_SOURCE_RESPONSE_DELAY) {

     // Fetch the source text only once.

     let textPromise = this._cache.get(aSource.url);

     if (textPromise) {

       return textPromise;

     }

     let deferred = promise.defer();

     this._cache.set(aSource.url, deferred.promise);

     // If the source text takes a long time to fetch, invoke a callback.

     if (aOnTimeout) {

       var fetchTimeout = window.setTimeout(() => aOnTimeout(aSource), aDelay);

     }

     // Get the source text from the active thread.

     this.activeThread.source(aSource)

         .source(({ error, message, source: text, contentType }) => {

       if (aOnTimeout) {

         window.clearTimeout(fetchTimeout);

       }

       if (error) {

         deferred.reject([aSource, message || error]);

       } else {

         deferred.resolve([aSource, text, contentType]);

       }

     });

     return deferred.promise;

   },

   /**

    * Starts fetching all the sources, silently.

    *

    * @param array aUrls

    *        The urls for the sources to fetch. If fetching a source's text

    *        takes too long, it will be discarded.

    * @return object

    *         A promise that is resolved after source texts have been fetched.

    */

   getTextForSources: function(aUrls) {

     let deferred = promise.defer();

     let pending = new Set(aUrls);

     let fetched = [];

     // Can't use promise.all, because if one fetch operation is rejected, then

     // everything is considered rejected, thus no other subsequent source will

     // be getting fetched. We don't want that. Something like Q's allSettled

     // would work like a charm here.

     // Try to fetch as many sources as possible.

     for (let url of aUrls) {

       let sourceItem = DebuggerView.Sources.getItemByValue(url);

       let sourceForm = sourceItem.attachment.source;

       this.getText(sourceForm, onTimeout).then(onFetch, onError);

     }

     /* Called if fetching a source takes too long. */

     function onTimeout(aSource) {

       onError([aSource]);

     }

     /* Called if fetching a source finishes successfully. */

     function onFetch([aSource, aText, aContentType]) {

       // If fetching the source has previously timed out, discard it this time.

       if (!pending.has(aSource.url)) {

         return;

       }

       pending.delete(aSource.url);

       fetched.push([aSource.url, aText, aContentType]);

       maybeFinish();

     }

     /* Called if fetching a source failed because of an error. */

     function onError([aSource, aError]) {

       pending.delete(aSource.url);

       maybeFinish();

     }

     /* Called every time something interesting happens while fetching sources. */

     function maybeFinish() {

       if (pending.size == 0) {

         // Sort the fetched sources alphabetically by their url.

         deferred.resolve(fetched.sort(([aFirst], [aSecond]) => aFirst > aSecond));

       }

     }

     return deferred.promise;

   }

 };

 /**

  * Tracer update the UI according to the messages exchanged with the tracer

  * actor.

  */

 function Tracer() {

   this._trace = null;

   this._idCounter = 0;

   this.onTraces = this.onTraces.bind(this);

 }

 Tracer.prototype = {

   get client() {

     return DebuggerController.client;

   },

   get traceClient() {

     return DebuggerController.traceClient;

   },

   get tracing() {

     return !!this._trace;

   },

   /**

    * Hooks up the debugger controller with the tracer client.

    */

   connect: function() {

     this._stack = [];

     this.client.addListener("traces", this.onTraces);

   },

   /**

    * Disconnects the debugger controller from the tracer client. Any further

    * communcation with the tracer actor will not have any effect on the UI.

    */

   disconnect: function() {

     this._stack = null;

     this.client.removeListener("traces", this.onTraces);

   },

   /**

    * Instructs the tracer actor to start tracing.

    */

   startTracing: function(aCallback = () => {}) {

     DebuggerView.Tracer.selectTab();

     if (this.tracing) {

       return;

     }

     this._trace = "dbg.trace" + Math.random();

     this.traceClient.startTrace([

       "name",

       "location",

       "parameterNames",

       "depth",

       "arguments",

       "return",

       "throw",

       "yield"

     ], this._trace, (aResponse) => {

       const { error } = aResponse;

       if (error) {

         DevToolsUtils.reportException("Tracer.prototype.startTracing", error);

         this._trace = null;

       }

       aCallback(aResponse);

     });

   },

   /**

    * Instructs the tracer actor to stop tracing.

    */

   stopTracing: function(aCallback = () => {}) {

     if (!this.tracing) {

       return;

     }

     this.traceClient.stopTrace(this._trace, aResponse => {

       const { error } = aResponse;

       if (error) {

         DevToolsUtils.reportException("Tracer.prototype.stopTracing", error);

       }

       this._trace = null;

       aCallback(aResponse);

     });

   },

   onTraces: function (aEvent, { traces }) {

     const tracesLength = traces.length;

     let tracesToShow;

     if (tracesLength > TracerView.MAX_TRACES) {

       tracesToShow = traces.slice(tracesLength - TracerView.MAX_TRACES,

                                   tracesLength);

       DebuggerView.Tracer.empty();

       this._stack.splice(0, this._stack.length);

     } else {

       tracesToShow = traces;

     }

     for (let t of tracesToShow) {

       if (t.type == "enteredFrame") {

         this._onCall(t);

       } else {

         this._onReturn(t);

       }

     }

     DebuggerView.Tracer.commit();

   },

   /**

    * Callback for handling a new call frame.

    */

   _onCall: function({ name, location, parameterNames, depth, arguments: args }) {

     const item = {

       name: name,

       location: location,

       id: this._idCounter++

     };

     this._stack.push(item);

     DebuggerView.Tracer.addTrace({

       type: "call",

       name: name,

       location: location,

       depth: depth,

       parameterNames: parameterNames,

       arguments: args,

       frameId: item.id

     });

   },

   /**

    * Callback for handling an exited frame.

    */

   _onReturn: function(aPacket) {

     if (!this._stack.length) {

       return;

     }

     const { name, id, location } = this._stack.pop();

     DebuggerView.Tracer.addTrace({

       type: aPacket.why,

       name: name,

       location: location,

       depth: aPacket.depth,

       frameId: id,

       returnVal: aPacket.return || aPacket.throw || aPacket.yield

     });

   },

   /**

    * Create an object which has the same interface as a normal object client,

    * but since we already have all the information for an object that we will

    * ever get (the server doesn't create actors when tracing, just firehoses

    * data and forgets about it) just return the data immdiately.

    *

    * @param Object aObject

    *        The tracer object "grip" (more like a limited snapshot).

    * @returns Object

    *          The synchronous client object.

    */

   syncGripClient: function(aObject) {

     return {

       get isFrozen() { return aObject.frozen; },

       get isSealed() { return aObject.sealed; },

       get isExtensible() { return aObject.extensible; },

       get ownProperties() { return aObject.ownProperties; },

       get prototype() { return null; },

       getParameterNames: callback => callback(aObject),

       getPrototypeAndProperties: callback => callback(aObject),

       getPrototype: callback => callback(aObject),

       getOwnPropertyNames: (callback) => {

         callback({

           ownPropertyNames: aObject.ownProperties

             ? Object.keys(aObject.ownProperties)

             : []

         });

       },

       getProperty: (property, callback) => {

         callback({

           descriptor: aObject.ownProperties

             ? aObject.ownProperties[property]

             : null

         });

       },

       getDisplayString: callback => callback("[object " + aObject.class + "]"),

       getScope: callback => callback({

         error: "scopeNotAvailable",

         message: "Cannot get scopes for traced objects"

       })

     };

   },

   /**

    * Wraps object snapshots received from the tracer server so that we can

    * differentiate them from long living object grips from the debugger server

    * in the variables view.

    *

    * @param Object aObject

    *        The object snapshot from the tracer actor.

    */

   WrappedObject: function(aObject) {

     this.object = aObject;

   }

 };

 /**

  * Handles breaking on event listeners in the currently debugged target.

  */

 function EventListeners() {

   this._onEventListeners = this._onEventListeners.bind(this);

 }

 EventListeners.prototype = {

   /**

    * A list of event names on which the debuggee will automatically pause

    * when invoked.

    */

   activeEventNames: [],

   /**

    * Updates the list of events types with listeners that, when invoked,

    * will automatically pause the debuggee. The respective events are

    * retrieved from the UI.

    */

   scheduleEventBreakpointsUpdate: function() {

     // Make sure we're not sending a batch of closely repeated requests.

     // This can easily happen when toggling all events of a certain type.

     setNamedTimeout("event-breakpoints-update", 0, () => {

       this.activeEventNames = DebuggerView.EventListeners.getCheckedEvents();

       gThreadClient.pauseOnDOMEvents(this.activeEventNames);

       // Notify that event breakpoints were added/removed on the server.

       window.emit(EVENTS.EVENT_BREAKPOINTS_UPDATED);

     });

   },

   /**

    * Fetches the currently attached event listeners from the debugee.

    */

   scheduleEventListenersFetch: function() {

     let getListeners = aCallback => gThreadClient.eventListeners(aResponse => {

       if (aResponse.error) {

         let msg = "Error getting event listeners: " + aResponse.message;

         DevToolsUtils.reportException("scheduleEventListenersFetch", msg);

         return;

       }

       let outstandingListenersDefinitionSite = aResponse.listeners.map(aListener => {

         const deferred = promise.defer();

         gThreadClient.pauseGrip(aListener.function).getDefinitionSite(aResponse => {

           if (aResponse.error) {

             const msg = "Error getting function definition site: " + aResponse.message;

             DevToolsUtils.reportException("scheduleEventListenersFetch", msg);

           } else {

             aListener.function.url = aResponse.url;

           }

           deferred.resolve(aListener);

         });

         return deferred.promise;

       });

       promise.all(outstandingListenersDefinitionSite).then(aListeners => {

         this._onEventListeners(aListeners);

         // Notify that event listeners were fetched and shown in the view,

         // and callback to resume the active thread if necessary.

         window.emit(EVENTS.EVENT_LISTENERS_FETCHED);

         aCallback && aCallback();

       });

     });

     // Make sure we're not sending a batch of closely repeated requests.

     // This can easily happen whenever new sources are fetched.

     setNamedTimeout("event-listeners-fetch", FETCH_EVENT_LISTENERS_DELAY, () => {

       if (gThreadClient.state != "paused") {

         gThreadClient.interrupt(() => getListeners(() => gThreadClient.resume()));

       } else {

         getListeners();

       }

     });

   },

   /**

    * Callback for a debugger's successful active thread eventListeners() call.

    */

   _onEventListeners: function(aListeners) {

     // Add all the listeners in the debugger view event linsteners container.

     for (let listener of aListeners) {

       DebuggerView.EventListeners.addListener(listener, { staged: true });

     }

     // Flushes all the prepared events into the event listeners container.

     DebuggerView.EventListeners.commit();

   }

 };

 /**

  * Handles all the breakpoints in the current debugger.

  */

 function Breakpoints() {

   this._onEditorBreakpointAdd = this._onEditorBreakpointAdd.bind(this);

   this._onEditorBreakpointRemove = this._onEditorBreakpointRemove.bind(this);

   this.addBreakpoint = this.addBreakpoint.bind(this);

   this.removeBreakpoint = this.removeBreakpoint.bind(this);

 }

 Breakpoints.prototype = {

   /**

    * A map of breakpoint promises as tracked by the debugger frontend.

    * The keys consist of a string representation of the breakpoint location.

    */

   _added: new Map(),

   _removing: new Map(),

   _disabled: new Map(),

   /**

    * Adds the source editor breakpoint handlers.

    *

    * @return object

    *         A promise that is resolved when the breakpoints finishes initializing.

    */

   initialize: function() {

     DebuggerView.editor.on("breakpointAdded", this._onEditorBreakpointAdd);

     DebuggerView.editor.on("breakpointRemoved", this._onEditorBreakpointRemove);

     // Initialization is synchronous, for now.

     return promise.resolve(null);

   },

   /**

    * Removes the source editor breakpoint handlers & all the added breakpoints.

    *

    * @return object

    *         A promise that is resolved when the breakpoints finishes destroying.

    */

   destroy: function() {

     DebuggerView.editor.off("breakpointAdded", this._onEditorBreakpointAdd);

     DebuggerView.editor.off("breakpointRemoved", this._onEditorBreakpointRemove);

     return this.removeAllBreakpoints();

   },

   /**

    * Event handler for new breakpoints that come from the editor.

    *

    * @param number aLine

    *        Line number where breakpoint was set.

    */

   _onEditorBreakpointAdd: function(_, aLine) {

     let url = DebuggerView.Sources.selectedValue;

     let location = { url: url, line: aLine + 1 };

     // Initialize the breakpoint, but don't update the editor, since this

     // callback is invoked because a breakpoint was added in the editor itself.

     this.addBreakpoint(location, { noEditorUpdate: true }).then(aBreakpointClient => {

       // If the breakpoint client has an "requestedLocation" attached, then

       // the original requested placement for the breakpoint wasn't accepted.

       // In this case, we need to update the editor with the new location.

       if (aBreakpointClient.requestedLocation) {

         DebuggerView.editor.removeBreakpoint(aBreakpointClient.requestedLocation.line - 1);

         DebuggerView.editor.addBreakpoint(aBreakpointClient.location.line - 1);

       }

       // Notify that we've shown a breakpoint in the source editor.

       window.emit(EVENTS.BREAKPOINT_SHOWN);

     });

   },

   /**

    * Event handler for breakpoints that are removed from the editor.

    *

    * @param number aLine

    *        Line number where breakpoint was removed.

    */

   _onEditorBreakpointRemove: function(_, aLine) {

     let url = DebuggerView.Sources.selectedValue;

     let location = { url: url, line: aLine + 1 };

     // Destroy the breakpoint, but don't update the editor, since this callback

     // is invoked because a breakpoint was removed from the editor itself.

     this.removeBreakpoint(location, { noEditorUpdate: true }).then(() => {

       // Notify that we've hidden a breakpoint in the source editor.

       window.emit(EVENTS.BREAKPOINT_HIDDEN);

     });

   },

   /**

    * Update the breakpoints in the editor view. This function takes the list of

    * breakpoints in the debugger and adds them back into the editor view.

    * This is invoked when the selected script is changed, or when new sources

    * are received via the _onNewSource and _onSourcesAdded event listeners.

    */

   updateEditorBreakpoints: function() {

     for (let breakpointPromise of this._addedOrDisabled) {

       breakpointPromise.then(aBreakpointClient => {

         let currentSourceUrl = DebuggerView.Sources.selectedValue;

         let breakpointUrl = aBreakpointClient.location.url;

         // Update the view only if the breakpoint is in the currently shown source.

         if (currentSourceUrl == breakpointUrl) {

           this._showBreakpoint(aBreakpointClient, { noPaneUpdate: true });

         }

       });

     }

   },

   /**

    * Update the breakpoints in the pane view. This function takes the list of

    * breakpoints in the debugger and adds them back into the breakpoints pane.

    * This is invoked when new sources are received via the _onNewSource and

    * _onSourcesAdded event listeners.

    */

   updatePaneBreakpoints: function() {

     for (let breakpointPromise of this._addedOrDisabled) {

       breakpointPromise.then(aBreakpointClient => {

         let container = DebuggerView.Sources;

         let breakpointUrl = aBreakpointClient.location.url;

         // Update the view only if the breakpoint exists in a known source.

         if (container.containsValue(breakpointUrl)) {

           this._showBreakpoint(aBreakpointClient, { noEditorUpdate: true });

         }

       });

     }

   },

   /**

    * Add a breakpoint.

    *

    * @param object aLocation

    *        The location where you want the breakpoint.

    *        This object must have two properties:

    *          - url: the breakpoint's source location.

    *          - line: the breakpoint's line number.

    *        It can also have the following optional properties:

    *          - condition: only pause if this condition evaluates truthy

    * @param object aOptions [optional]

    *        Additional options or flags supported by this operation:

    *          - openPopup: tells if the expression popup should be shown.

    *          - noEditorUpdate: tells if you want to skip editor updates.

    *          - noPaneUpdate: tells if you want to skip breakpoint pane updates.

    * @return object

    *         A promise that is resolved after the breakpoint is added, or

    *         rejected if there was an error.

    */

   addBreakpoint: Task.async(function*(aLocation, aOptions = {}) {

     // Make sure a proper location is available.

     if (!aLocation) {

       throw new Error("Invalid breakpoint location.");

     }

     let addedPromise, removingPromise;

     // If the breakpoint was already added, or is currently being added at the

     // specified location, then return that promise immediately.

     if ((addedPromise = this._getAdded(aLocation))) {

       return addedPromise;

     }

     // If the breakpoint is currently being removed from the specified location,

     // then wait for that to finish.

     if ((removingPromise = this._getRemoving(aLocation))) {

       yield removingPromise;

     }

     let deferred = promise.defer();

     // Remember the breakpoint initialization promise in the store.

     let identifier = this.getIdentifier(aLocation);

     this._added.set(identifier, deferred.promise);

     // Try adding the breakpoint.

     gThreadClient.setBreakpoint(aLocation, Task.async(function*(aResponse, aBreakpointClient) {

       // If the breakpoint response has an "actualLocation" attached, then

       // the original requested placement for the breakpoint wasn't accepted.

       if (aResponse.actualLocation) {

         // Remember the initialization promise for the new location instead.

         let oldIdentifier = identifier;

         let newIdentifier = identifier = this.getIdentifier(aResponse.actualLocation);

         this._added.delete(oldIdentifier);

         this._added.set(newIdentifier, deferred.promise);

       }

       // By default, new breakpoints are always enabled. Disabled breakpoints

       // are, in fact, removed from the server but preserved in the frontend,

       // so that they may not be forgotten across target navigations.

       let disabledPromise = this._disabled.get(identifier);

       if (disabledPromise) {

         let aPrevBreakpointClient = yield disabledPromise;

         let condition = aPrevBreakpointClient.getCondition();

         this._disabled.delete(identifier);

         if (condition) {

           aBreakpointClient = yield aBreakpointClient.setCondition(

             gThreadClient,

             condition

           );

         }

       }

       if (aResponse.actualLocation) {

         // Store the originally requested location in case it's ever needed

         // and update the breakpoint client with the actual location.

         aBreakpointClient.requestedLocation = aLocation;

         aBreakpointClient.location = aResponse.actualLocation;

       }

       // Preserve information about the breakpoint's line text, to display it

       // in the sources pane without requiring fetching the source (for example,

       // after the target navigated). Note that this will get out of sync

       // if the source text contents change.

       let line = aBreakpointClient.location.line - 1;

       aBreakpointClient.text = DebuggerView.editor.getText(line).trim();

       // Show the breakpoint in the editor and breakpoints pane, and resolve.

       this._showBreakpoint(aBreakpointClient, aOptions);

       // Notify that we've added a breakpoint.

       window.emit(EVENTS.BREAKPOINT_ADDED, aBreakpointClient);

       deferred.resolve(aBreakpointClient);

     }.bind(this)));

     return deferred.promise;

   }),

   /**

    * Remove a breakpoint.

    *

    * @param object aLocation

    *        @see DebuggerController.Breakpoints.addBreakpoint

    * @param object aOptions [optional]

    *        @see DebuggerController.Breakpoints.addBreakpoint

    * @return object

    *         A promise that is resolved after the breakpoint is removed, or

    *         rejected if there was an error.

    */

   removeBreakpoint: function(aLocation, aOptions = {}) {

     // Make sure a proper location is available.

     if (!aLocation) {

       return promise.reject(new Error("Invalid breakpoint location."));

     }

     // If the breakpoint was already removed, or has never even been added,

     // then return a resolved promise immediately.

     let addedPromise = this._getAdded(aLocation);

     if (!addedPromise) {

       return promise.resolve(aLocation);

     }

     // If the breakpoint is currently being removed from the specified location,

     // then return that promise immediately.

     let removingPromise = this._getRemoving(aLocation);

     if (removingPromise) {

       return removingPromise;

     }

     let deferred = promise.defer();

     // Remember the breakpoint removal promise in the store.

     let identifier = this.getIdentifier(aLocation);

     this._removing.set(identifier, deferred.promise);

     // Retrieve the corresponding breakpoint client first.

     addedPromise.then(aBreakpointClient => {

       // Try removing the breakpoint.

       aBreakpointClient.remove(aResponse => {

         // If there was an error removing the breakpoint, reject the promise

         // and forget about it that the breakpoint may be re-removed later.

         if (aResponse.error) {

           deferred.reject(aResponse);

           return void this._removing.delete(identifier);

         }

         // When a breakpoint is removed, the frontend may wish to preserve some

         // details about it, so that it can be easily re-added later. In such

         // cases, breakpoints are marked and stored as disabled, so that they

         // may not be forgotten across target navigations.

         if (aOptions.rememberDisabled) {

           aBreakpointClient.disabled = true;

           this._disabled.set(identifier, promise.resolve(aBreakpointClient));

         }

         // Forget both the initialization and removal promises from the store.

         this._added.delete(identifier);

         this._removing.delete(identifier);

         // Hide the breakpoint from the editor and breakpoints pane, and resolve.

         this._hideBreakpoint(aLocation, aOptions);

         // Notify that we've removed a breakpoint.

         window.emit(EVENTS.BREAKPOINT_REMOVED, aLocation);

         deferred.resolve(aLocation);

       });

     });

     return deferred.promise;

   },

   /**

    * Removes all the currently enabled breakpoints.

    *

    * @return object

    *         A promise that is resolved after all breakpoints are removed, or

    *         rejected if there was an error.

    */

   removeAllBreakpoints: function() {

     /* Gets an array of all the existing breakpoints promises. */

     let getActiveBreakpoints = (aPromises, aStore = []) => {

       for (let [, breakpointPromise] of aPromises) {

         aStore.push(breakpointPromise);

       }

       return aStore;

     }

     /* Gets an array of all the removed breakpoints promises. */

     let getRemovedBreakpoints = (aClients, aStore = []) => {

       for (let breakpointClient of aClients) {

         aStore.push(this.removeBreakpoint(breakpointClient.location));

       }

       return aStore;

     }

     // First, populate an array of all the currently added breakpoints promises.

     // Then, once all the breakpoints clients are retrieved, populate an array

     // of all the removed breakpoints promises and wait for their fulfillment.

     return promise.all(getActiveBreakpoints(this._added)).then(aBreakpointClients => {

       return promise.all(getRemovedBreakpoints(aBreakpointClients));

     });

   },

   /**

    * Update the condition of a breakpoint.

    *

    * @param object aLocation

    *        @see DebuggerController.Breakpoints.addBreakpoint

    * @param string aClients

    *        The condition to set on the breakpoint

    * @return object

    *         A promise that will be resolved with the breakpoint client

    */

   updateCondition: function(aLocation, aCondition) {

     let addedPromise = this._getAdded(aLocation);

     if (!addedPromise) {

       return promise.reject(new Error('breakpoint does not exist ' +

                                       'in specified location'));

     }

     var promise = addedPromise.then(aBreakpointClient => {

       return aBreakpointClient.setCondition(gThreadClient, aCondition);

     });

     // `setCondition` returns a new breakpoint that has the condition,

     // so we need to update the store

     this._added.set(this.getIdentifier(aLocation), promise);

     return promise;

   },

   /**

    * Update the editor and breakpoints pane to show a specified breakpoint.

    *

    * @param object aBreakpointData

    *        Information about the breakpoint to be shown.

    *        This object must have the following properties:

    *          - location: the breakpoint's source location and line number

    *          - disabled: the breakpoint's disabled state, boolean

    *          - text: the breakpoint's line text to be displayed

    * @param object aOptions [optional]

    *        @see DebuggerController.Breakpoints.addBreakpoint

    */

   _showBreakpoint: function(aBreakpointData, aOptions = {}) {

     let currentSourceUrl = DebuggerView.Sources.selectedValue;

     let location = aBreakpointData.location;

     // Update the editor if required.

     if (!aOptions.noEditorUpdate && !aBreakpointData.disabled) {

       if (location.url == currentSourceUrl) {

         DebuggerView.editor.addBreakpoint(location.line - 1);

       }

     }

     // Update the breakpoints pane if required.

     if (!aOptions.noPaneUpdate) {

       DebuggerView.Sources.addBreakpoint(aBreakpointData, aOptions);

     }

   },

   /**

    * Update the editor and breakpoints pane to hide a specified breakpoint.

    *

    * @param object aLocation

    *        @see DebuggerController.Breakpoints.addBreakpoint

    * @param object aOptions [optional]

    *        @see DebuggerController.Breakpoints.addBreakpoint

    */

   _hideBreakpoint: function(aLocation, aOptions = {}) {

     let currentSourceUrl = DebuggerView.Sources.selectedValue;

     // Update the editor if required.

     if (!aOptions.noEditorUpdate) {

       if (aLocation.url == currentSourceUrl) {

         DebuggerView.editor.removeBreakpoint(aLocation.line - 1);

       }

     }

     // Update the breakpoints pane if required.

     if (!aOptions.noPaneUpdate) {

       DebuggerView.Sources.removeBreakpoint(aLocation);

     }

   },

   /**

    * Get a Promise for the BreakpointActor client object which is already added

    * or currently being added at the given location.

    *

    * @param object aLocation

    *        @see DebuggerController.Breakpoints.addBreakpoint

    * @return object | null

    *         A promise that is resolved after the breakpoint is added, or

    *         null if no breakpoint was found.

    */

   _getAdded: function(aLocation) {

     return this._added.get(this.getIdentifier(aLocation));

   },

   /**

    * Get a Promise for the BreakpointActor client object which is currently

    * being removed from the given location.

    *

    * @param object aLocation

    *        @see DebuggerController.Breakpoints.addBreakpoint

    * @return object | null

    *         A promise that is resolved after the breakpoint is removed, or

    *         null if no breakpoint was found.

    */

   _getRemoving: function(aLocation) {

     return this._removing.get(this.getIdentifier(aLocation));

   },

   /**

    * Get an identifier string for a given location. Breakpoint promises are

    * identified in the store by a string representation of their location.

    *

    * @param object aLocation

    *        The location to serialize to a string.

    * @return string

    *         The identifier string.

    */

   getIdentifier: function(aLocation) {

     return aLocation.url + ":" + aLocation.line;

   }

 };

 /**

  * Gets all Promises for the BreakpointActor client objects that are

  * either enabled (added to the server) or disabled (removed from the server,

  * but for which some details are preserved).

  */

 Object.defineProperty(Breakpoints.prototype, "_addedOrDisabled", {

   get: function* () {

     yield* this._added.values();

     yield* this._disabled.values();

   }

 });

 /**

  * Localization convenience methods.

  */

 let L10N = new ViewHelpers.L10N(DBG_STRINGS_URI);

 /**

  * Shortcuts for accessing various debugger preferences.

  */

 let Prefs = new ViewHelpers.Prefs("devtools", {

   sourcesWidth: ["Int", "debugger.ui.panes-sources-width"],

   instrumentsWidth: ["Int", "debugger.ui.panes-instruments-width"],

   panesVisibleOnStartup: ["Bool", "debugger.ui.panes-visible-on-startup"],

   variablesSortingEnabled: ["Bool", "debugger.ui.variables-sorting-enabled"],

   variablesOnlyEnumVisible: ["Bool", "debugger.ui.variables-only-enum-visible"],

   variablesSearchboxVisible: ["Bool", "debugger.ui.variables-searchbox-visible"],

   pauseOnExceptions: ["Bool", "debugger.pause-on-exceptions"],

   ignoreCaughtExceptions: ["Bool", "debugger.ignore-caught-exceptions"],

   sourceMapsEnabled: ["Bool", "debugger.source-maps-enabled"],

   prettyPrintEnabled: ["Bool", "debugger.pretty-print-enabled"],

   autoPrettyPrint: ["Bool", "debugger.auto-pretty-print"],

   tracerEnabled: ["Bool", "debugger.tracer"],

   editorTabSize: ["Int", "editor.tabsize"]

 });

 /**

  * Convenient way of emitting events from the panel window.

  */

 EventEmitter.decorate(this);

 /**

  * Preliminary setup for the DebuggerController object.

  */

 DebuggerController.initialize();

 DebuggerController.Parser = new Parser();

 DebuggerController.ThreadState = new ThreadState();

 DebuggerController.StackFrames = new StackFrames();

 DebuggerController.SourceScripts = new SourceScripts();

 DebuggerController.Breakpoints = new Breakpoints();

 DebuggerController.Breakpoints.DOM = new EventListeners();

 DebuggerController.Tracer = new Tracer();

 /**

  * Export some properties to the global scope for easier access.

  */

 Object.defineProperties(window, {

   "gTarget": {

     get: function() DebuggerController._target

   },

   "gHostType": {

     get: function() DebuggerView._hostType

   },

   "gClient": {

     get: function() DebuggerController.client

   },

   "gThreadClient": {

     get: function() DebuggerController.activeThread

   },

   "gCallStackPageSize": {

     get: function() CALL_STACK_PAGE_SIZE

   }

 });

 /**

  * Helper method for debugging.

  * @param string

  */

 function dumpn(str) {

   if (wantLogging) {

     dump("DBG-FRONTEND: " + str + "\n");

   }

 }

 let wantLogging = Services.prefs.getBoolPref("devtools.debugger.log");