DevTools: carefully cleanup javascript sourcemaps

third_party/WebKit/Source/devtools/front_end/sdk/SourceMapManager.js

 // Copyright 2017 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.
 
 /**
  * @template T
  */
 SDK.SourceMapManager = class extends SDK.SDKObject {
   /**
    * @param {!SDK.Target} target
@@ skipping 113 matching lines @@
       return;
     this._relativeSourceURL.set(client, sourceURL);
     this._relativeSourceMapURL.set(client, sourceMapURL);
     this._resolvedSourceMapURL.set(client, resolvedURLs.sourceMapURL);
 
     sourceURL = resolvedURLs.sourceURL;
     sourceMapURL = resolvedURLs.sourceMapURL;
     if (!this._isEnabled)
       return;
 
+    this.dispatchEventToListeners(SDK.SourceMapManager.Events.SourceMapWillAttach, client);
+
     if (this._sourceMapByURL.has(sourceMapURL)) {
       attach.call(this, sourceMapURL, client);
       return;
     }
     if (!this._sourceMapURLToLoadingClients.has(sourceMapURL)) {
       SDK.TextSourceMap.load(sourceMapURL, sourceURL)
           .then(onTextSourceMapLoaded.bind(this, sourceMapURL))
           .then(onSourceMap.bind(this, sourceMapURL));
     }
     this._sourceMapURLToLoadingClients.set(sourceMapURL, client);
@@ skipping 18 matching lines @@
 
     /**
      * @param {string} sourceMapURL
      * @param {?SDK.SourceMap} sourceMap
      * @this {SDK.SourceMapManager}
      */
     function onSourceMap(sourceMapURL, sourceMap) {
       this._sourceMapLoadedForTest();
       var clients = this._sourceMapURLToLoadingClients.get(sourceMapURL);
       this._sourceMapURLToLoadingClients.removeAll(sourceMapURL);
-      if (!sourceMap || !clients.size)
+      if (!clients.size)
         return;
+      if (!sourceMap) {
+        for (var client of clients)
+          this.dispatchEventToListeners(SDK.SourceMapManager.Events.SourceMapFailedToAttach, client);
+        return;
+      }
       this._sourceMapByURL.set(sourceMapURL, sourceMap);
       for (var client of clients)
         attach.call(this, sourceMapURL, client);
     }
 
     /**
      * @param {string} sourceMapURL
      * @param {!T} client
      * @this {SDK.SourceMapManager}
      */
@@ skipping 26 matching lines @@
    */
   detachSourceMap(client) {
     var sourceMapURL = this._resolvedSourceMapURL.get(client);
     this._relativeSourceURL.delete(client);
     this._relativeSourceMapURL.delete(client);
     this._resolvedSourceMapURL.delete(client);
 
     if (!sourceMapURL)
       return;
     if (!this._sourceMapURLToClients.hasValue(sourceMapURL, client)) {
-      this._sourceMapURLToLoadingClients.remove(sourceMapURL, client);
+      if (this._sourceMapURLToLoadingClients.remove(sourceMapURL, client))
+        this.dispatchEventToListeners(SDK.SourceMapManager.Events.SourceMapFailedToAttach, client);
       return;
     }
     this._sourceMapURLToClients.remove(sourceMapURL, client);
     var sourceMap = this._sourceMapByURL.get(sourceMapURL);
     if (!this._sourceMapURLToClients.has(sourceMapURL))
       this._sourceMapByURL.delete(sourceMapURL);
     this.dispatchEventToListeners(
         SDK.SourceMapManager.Events.SourceMapDetached, {client: client, sourceMap: sourceMap});
   }
 
   _sourceMapLoadedForTest() {
   }
 
   dispose() {
     SDK.targetManager.removeEventListener(
         SDK.TargetManager.Events.InspectedURLChanged, this._inspectedURLChanged, this);
   }
 };
 
 SDK.SourceMapManager.Events = {
+  SourceMapWillAttach: Symbol('SourceMapWillAttach'),
+  SourceMapFailedToAttach: Symbol('SourceMapFailedToAttach'),
   SourceMapAttached: Symbol('SourceMapAttached'),
   SourceMapDetached: Symbol('SourceMapDetached'),
   SourceMapChanged: Symbol('SourceMapChanged')
 };