DevTools: migrate from external Maps to symbols in the bindings objects.

third_party/WebKit/Source/devtools/front_end/bindings/DebuggerWorkspaceBinding.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @implements {SDK.TargetManager.Observer}
  * @unrestricted
  */
 Bindings.DebuggerWorkspaceBinding = class extends Common.Object {
   /**
    * @param {!SDK.TargetManager} targetManager
@@ skipping 68 matching lines @@
   pushSourceMapping(script, sourceMapping) {
     var info = this._ensureInfoForScript(script);
     info._pushSourceMapping(sourceMapping);
   }
 
   /**
    * @param {!SDK.Script} script
    * @return {!Bindings.DebuggerSourceMapping}
    */
   popSourceMapping(script) {
-    var info = this._infoForScript(script.target(), script.scriptId);
+    var info = this._infoForScript(script);
     console.assert(info);
     return info._popSourceMapping();
   }
 
   /**
    * @param {!SDK.Target} target
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {?Bindings.DebuggerSourceMapping} sourceMapping
    */
   setSourceMapping(target, uiSourceCode, sourceMapping) {
     var data = this._targetToData.get(target);
     if (data)
       data._setSourceMapping(uiSourceCode, sourceMapping);
   }
 
   /**
    * @param {!SDK.Script} script
    */
   updateLocations(script) {
-    var info = this._infoForScript(script.target(), script.scriptId);
+    var info = this._infoForScript(script);
     if (info)
       info._updateLocations();
   }
 
   /**
    * @param {!SDK.DebuggerModel.Location} rawLocation
    * @param {function(!Bindings.LiveLocation)} updateDelegate
    * @param {!Bindings.LiveLocationPool} locationPool
    * @return {!Bindings.DebuggerWorkspaceBinding.Location}
    */
   createLiveLocation(rawLocation, updateDelegate, locationPool) {
-    var info = this._infoForScript(rawLocation.target(), rawLocation.scriptId);
+    var info = this._infoForScript(rawLocation.script());
     console.assert(info);
     var location =
         new Bindings.DebuggerWorkspaceBinding.Location(info._script, rawLocation, this, updateDelegate, locationPool);
     info._addLocation(location);
     return location;
   }
 
   /**
    * @param {!Array<!SDK.DebuggerModel.Location>} rawLocations
    * @param {function(!Bindings.LiveLocation)} updateDelegate
@@ skipping 23 matching lines @@
     var liveLocation = this.createLiveLocation(location, updateDelegate, locationPool);
     this._registerCallFrameLiveLocation(target, liveLocation);
     return liveLocation;
   }
 
   /**
    * @param {!SDK.DebuggerModel.Location} rawLocation
    * @return {!Workspace.UILocation}
    */
   rawLocationToUILocation(rawLocation) {
-    var info = this._infoForScript(rawLocation.target(), rawLocation.scriptId);
+    var info = this._infoForScript(rawLocation.script());
     console.assert(info);
     return info._rawLocationToUILocation(rawLocation);
   }
 
   /**
    * @param {!SDK.Target} target
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {number} lineNumber
    * @param {number} columnNumber
    * @return {?SDK.DebuggerModel.Location}
@@ skipping 97 matching lines @@
     var targetData = this._targetToData.get(target);
     targetData.callFrameLocations.valuesArray().forEach((location) => this._removeLiveLocation(location));
     targetData.callFrameLocations.clear();
   }
 
   /**
    * @param {!SDK.Script} script
    * @return {!Bindings.DebuggerWorkspaceBinding.ScriptInfo}
    */
   _ensureInfoForScript(script) {
-    var scriptDataMap = this._targetToData.get(script.target()).scriptDataMap;
-    var info = scriptDataMap.get(script.scriptId);
+    var info = script[Bindings.DebuggerWorkspaceBinding._scriptInfoSymbol];
     if (!info) {
       info = new Bindings.DebuggerWorkspaceBinding.ScriptInfo(script);
-      scriptDataMap.set(script.scriptId, info);
+      script[Bindings.DebuggerWorkspaceBinding._scriptInfoSymbol] = info;
     }
     return info;
   }
 
   /**
-   * @param {!SDK.Target} target
-   * @param {string} scriptId
+   * @param {?SDK.Script} script
    * @return {?Bindings.DebuggerWorkspaceBinding.ScriptInfo}
    */
-  _infoForScript(target, scriptId) {
-    var data = this._targetToData.get(target);
-    if (!data)
+  _infoForScript(script) {
+    if (!script)
       return null;
-    return data.scriptDataMap.get(scriptId) || null;
+    return script[Bindings.DebuggerWorkspaceBinding._scriptInfoSymbol] || null;
   }
 
   /**
    * @param {!SDK.Target} target
    * @param {!Bindings.DebuggerWorkspaceBinding.Location} location
    */
   _registerCallFrameLiveLocation(target, location) {
     var locations = this._targetToData.get(target).callFrameLocations;
     locations.add(location);
   }
 
   /**
    * @param {!Bindings.DebuggerWorkspaceBinding.Location} location
    */
   _removeLiveLocation(location) {
-    var info = this._infoForScript(location._script.target(), location._script.scriptId);
+    var info = this._infoForScript(location._script);
     if (info)
       info._removeLocation(location);
   }
 
   /**
    * @param {!Common.Event} event
    */
   _debuggerResumed(event) {
     var debuggerModel = /** @type {!SDK.DebuggerModel} */ (event.data);
     this._reset(debuggerModel.target());
   }
 };
 
+Bindings.DebuggerWorkspaceBinding._scriptInfoSymbol = Symbol('scriptDataMap');
+Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol = Symbol('sourceMapping');
+
 /**
  * @unrestricted
  */
 Bindings.DebuggerWorkspaceBinding.TargetData = class {
   /**
    * @param {!SDK.DebuggerModel} debuggerModel
    * @param {!Bindings.DebuggerWorkspaceBinding} debuggerWorkspaceBinding
    */
   constructor(debuggerModel, debuggerWorkspaceBinding) {
     this._debuggerModel = debuggerModel;
     this._debuggerWorkspaceBinding = debuggerWorkspaceBinding;
 
-    /** @type {!Map.<string, !Bindings.DebuggerWorkspaceBinding.ScriptInfo>} */
-    this.scriptDataMap = new Map();
-
     /** @type {!Set.<!Bindings.DebuggerWorkspaceBinding.Location>} */
     this.callFrameLocations = new Set();
 
     var workspace = debuggerWorkspaceBinding._workspace;
 
     this._defaultMapping = new Bindings.DefaultScriptMapping(debuggerModel, workspace, debuggerWorkspaceBinding);
     this._resourceMapping = new Bindings.ResourceScriptMapping(debuggerModel, workspace, debuggerWorkspaceBinding);
     this._compilerMapping = new Bindings.CompilerScriptMapping(
         debuggerModel, workspace, Bindings.NetworkProject.forTarget(this._debuggerModel.target()),
         debuggerWorkspaceBinding);
 
-    /** @type {!Map.<!Workspace.UISourceCode, !Bindings.DebuggerSourceMapping>} */
-    this._uiSourceCodeToSourceMapping = new Map();
-
     debuggerModel.setBeforePausedCallback(this._beforePaused.bind(this));
     this._eventListeners = [
       debuggerModel.addEventListener(SDK.DebuggerModel.Events.ParsedScriptSource, this._parsedScriptSource, this),
-      debuggerModel.addEventListener(SDK.DebuggerModel.Events.FailedToParseScriptSource, this._parsedScriptSource, this)
+      debuggerModel.addEventListener(
+          SDK.DebuggerModel.Events.FailedToParseScriptSource, this._parsedScriptSource, this),
     ];
   }
 
   /**
    * @param {!SDK.DebuggerPausedDetails} debuggerPausedDetails
    * @return {boolean}
    */
   _beforePaused(debuggerPausedDetails) {
     return !!this._compilerMapping.mapsToSourceCode(debuggerPausedDetails.callFrames[0].location());
   }
 
   /**
    * @param {!Common.Event} event
    */
   _parsedScriptSource(event) {
     var script = /** @type {!SDK.Script} */ (event.data);
     this._defaultMapping.addScript(script);
     this._resourceMapping.addScript(script);
 
     if (Common.moduleSetting('jsSourceMapsEnabled').get())
       this._compilerMapping.addScript(script);
   }
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {?Bindings.DebuggerSourceMapping} sourceMapping
    */
   _setSourceMapping(uiSourceCode, sourceMapping) {
-    if (this._uiSourceCodeToSourceMapping.get(uiSourceCode) === sourceMapping)
+    if (uiSourceCode[Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol] === sourceMapping)
       return;
 
     if (sourceMapping)
-      this._uiSourceCodeToSourceMapping.set(uiSourceCode, sourceMapping);
+      uiSourceCode[Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol] = sourceMapping;
     else
-      this._uiSourceCodeToSourceMapping.remove(uiSourceCode);
+      delete uiSourceCode[Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol];
 
-    this._debuggerWorkspaceBinding.dispatchEventToListeners(Bindings.DebuggerWorkspaceBinding.Events.SourceMappingChanged, {
-      uiSourceCode: uiSourceCode,
-      target: this._debuggerModel.target(),
-      isIdentity: sourceMapping ? sourceMapping.isIdentity() : false
-    });
+    this._debuggerWorkspaceBinding.dispatchEventToListeners(
+        Bindings.DebuggerWorkspaceBinding.Events.SourceMappingChanged, {
+          uiSourceCode: uiSourceCode,
+          target: this._debuggerModel.target(),
+          isIdentity: sourceMapping ? sourceMapping.isIdentity() : false
+        });
   }
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {number} lineNumber
    * @param {number} columnNumber
    * @return {?SDK.DebuggerModel.Location}
    */
   _uiLocationToRawLocation(uiSourceCode, lineNumber, columnNumber) {
-    var sourceMapping = this._uiSourceCodeToSourceMapping.get(uiSourceCode);
+    var sourceMapping = uiSourceCode[Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol];
     return sourceMapping ? sourceMapping.uiLocationToRawLocation(uiSourceCode, lineNumber, columnNumber) : null;
   }
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {number} lineNumber
    * @return {boolean}
    */
   _uiLineHasMapping(uiSourceCode, lineNumber) {
-    var sourceMapping = this._uiSourceCodeToSourceMapping.get(uiSourceCode);
+    var sourceMapping = uiSourceCode[Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol];
     return sourceMapping ? sourceMapping.uiLineHasMapping(uiSourceCode, lineNumber) : true;
   }
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
    */
   _uiSourceCodeRemoved(uiSourceCode) {
-    this._uiSourceCodeToSourceMapping.remove(uiSourceCode);
+    delete uiSourceCode[Bindings.DebuggerWorkspaceBinding._sourceMappingSymbol];
   }
 
   _dispose() {
     this._debuggerModel.setBeforePausedCallback(null);
     Common.EventTarget.removeEventListeners(this._eventListeners);
     this._compilerMapping.dispose();
     this._resourceMapping.dispose();
     this._defaultMapping.dispose();
-    this._uiSourceCodeToSourceMapping.clear();
   }
 };
 
 /** @enum {symbol} */
 Bindings.DebuggerWorkspaceBinding.Events = {
   SourceMappingChanged: Symbol('SourceMappingChanged'),
 };
 
 
 /**
  * @unrestricted
  */
 Bindings.DebuggerWorkspaceBinding.ScriptInfo = class {
   /**
    * @param {!SDK.Script} script
    */
   constructor(script) {
     this._script = script;
-
-    /** @type {!Array.<!Bindings.DebuggerSourceMapping>} */
-    this._sourceMappings = [];
-
-    /** @type {!Set<!Bindings.LiveLocation>} */
-    this._locations = new Set();
+    // We create a lot of these, do not add arrays/collections/expensive data structures.
   }
 
   /**
    * @param {!Bindings.DebuggerSourceMapping} sourceMapping
    */
   _pushSourceMapping(sourceMapping) {
-    this._sourceMappings.push(sourceMapping);
+    if (this._sourceMapping) {
+      if (!this._backupMappings) {
+        /** @type {!Array.<!Bindings.DebuggerSourceMapping>} */
+        this._backupMappings = [];
+      }
+      this._backupMappings.push(this._sourceMapping);
+    }
+    this._sourceMapping = sourceMapping;
     this._updateLocations();
   }
 
   /**
    * @return {!Bindings.DebuggerSourceMapping}
    */
   _popSourceMapping() {
-    var sourceMapping = this._sourceMappings.pop();
+    var sourceMapping = this._sourceMapping;
+    this._sourceMapping = this._backupMappings.pop();

[dgozman, 2017/01/04 01:04:08]

this._backupMappings could be undefined

[pfeldman, 2017/01/04 01:13:47]

Done.

     this._updateLocations();
     return sourceMapping;
   }
 
   /**
    * @param {!Bindings.LiveLocation} location
    */
   _addLocation(location) {
+    if (!this._locations) {
+      /** @type {!Set<!Bindings.LiveLocation>} */
+      this._locations = new Set();
+    }
     this._locations.add(location);
     location.update();
   }
 
   /**
    * @param {!Bindings.LiveLocation} location
    */
   _removeLocation(location) {
+    if (!this._locations)
+      return;
     this._locations.delete(location);
   }
 
   _updateLocations() {
+    if (!this._locations)
+      return;
     for (var location of this._locations)
       location.update();
   }
 
   /**
    * @param {!SDK.DebuggerModel.Location} rawLocation
    * @return {!Workspace.UILocation}
    */
   _rawLocationToUILocation(rawLocation) {
-    var uiLocation;
-    for (var i = this._sourceMappings.length - 1; !uiLocation && i >= 0; --i)
-      uiLocation = this._sourceMappings[i].rawLocationToUILocation(rawLocation);
+    var uiLocation = this._sourceMapping ? this._sourceMapping.rawLocationToUILocation(rawLocation) : null;
+    if (!uiLocation && this._backupMappings) {
+      for (var i = this._backupMappings.length - 1; !uiLocation && i >= 0; --i)
+        uiLocation = this._backupMappings[i].rawLocationToUILocation(rawLocation);
+    }
     console.assert(uiLocation, 'Script raw location cannot be mapped to any UI location.');
     return /** @type {!Workspace.UILocation} */ (uiLocation);
   }
 };
 
 /**
  * @unrestricted
  */
 Bindings.DebuggerWorkspaceBinding.Location = class extends Bindings.LiveLocationWithPool {
   /**
@@ skipping 132 matching lines @@
    * @param {number} lineNumber
    * @return {boolean}
    */
   uiLineHasMapping(uiSourceCode, lineNumber) {}
 };
 
 /**
  * @type {!Bindings.DebuggerWorkspaceBinding}
  */
 Bindings.debuggerWorkspaceBinding;