DevTools: fix race when revealing formatted source code

third_party/WebKit/Source/devtools/front_end/sources/SourceFormatter.js

Index: third_party/WebKit/Source/devtools/front_end/sources/SourceFormatter.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sources/SourceFormatter.js b/third_party/WebKit/Source/devtools/front_end/sources/SourceFormatter.js
index 4ce4d5e5c47727ed9d7f1414dee25273f9b841d0..a6d00a8a9b5ef90b1e5f99c510a7efc9a8cf3356 100644
--- a/third_party/WebKit/Source/devtools/front_end/sources/SourceFormatter.js
+++ b/third_party/WebKit/Source/devtools/front_end/sources/SourceFormatter.js
@@ -36,7 +36,7 @@ Sources.SourceFormatter = class {
         Workspace.workspace, this._projectId, Workspace.projectTypes.Formatter, 'formatter',
         true /* isServiceProject */);
 
-    /** @type {!Map<string, !Workspace.UISourceCode>} */
+    /** @type {!Map<string, !Promise<!Sources.SourceFormatData>>} */
     this._formattedPaths = new Map();
     this._scriptMapping = new Sources.SourceFormatter.ScriptMapping();
     this._styleMapping = new Sources.SourceFormatter.StyleMapping();
@@ -49,9 +49,9 @@ Sources.SourceFormatter = class {
    */
   _onUISourceCodeRemoved(event) {
     var uiSourceCode = /** @type {!Workspace.UISourceCode} */ (event.data);
-    var formattedUISourceCode = this._formattedPaths.get(uiSourceCode.project().id() + ':' + uiSourceCode.url());
-    if (formattedUISourceCode)
-      this.discardFormattedUISourceCode(formattedUISourceCode);
+    var formatDataPromise = this._formattedPaths.get(uiSourceCode.project().id() + ':' + uiSourceCode.url());
+    if (formatDataPromise)
+      formatDataPromise.then(formatData => this.discardFormattedUISourceCode(formatData.formattedSourceCode));

[lushnikov, 2017/05/17 23:39:08]

Since you're caching per projectId + uiSourceCodeURL, do you expect the
_uiSourceCodeRemoved to happen multiple times?

In this case, the discardFormattedUISourceCode might be called multiple times,
which you probably don't want.

(However, caching by project.id() + url is almost the same as caching by
UISourceCode instance itself)

[lushnikov, 2017/05/17 23:57:32]

this._formattedPath.delete(path);

   }
 
   /**
@@ -67,8 +67,9 @@ Sources.SourceFormatter = class {
     this._scriptMapping._setSourceMappingEnabled(formatData, false);
     this._styleMapping._setSourceMappingEnabled(formatData, false);
     this._project.removeFile(formattedUISourceCode.url());
-    this._formattedPaths.remove(formatData.originalPath());
-    return formatData.originalSourceCode;
+    var originalSourceCode = formatData.originalSourceCode;
+    this._formattedPaths.remove(originalSourceCode.project().id() + ':' + originalSourceCode.url());
+    return originalSourceCode;
   }
 
   /**
@@ -84,16 +85,18 @@ Sources.SourceFormatter = class {
    * @return {!Promise<!Sources.SourceFormatData>}
    */
   async format(uiSourceCode) {
-    var formattedUISourceCode = this._formattedPaths.get(uiSourceCode.project().id() + ':' + uiSourceCode.url());
-    if (formattedUISourceCode)
-      return Sources.SourceFormatData._for(formattedUISourceCode);
+    var path = uiSourceCode.project().id() + ':' + uiSourceCode.url();
+    var resultPromise = this._formattedPaths.get(path);
+    if (resultPromise)
+      return resultPromise;
 
-    var content = await uiSourceCode.requestContent();
-    var highlighterType = Bindings.NetworkProject.uiSourceCodeMimeType(uiSourceCode);
     var fulfillFormatPromise;
-    var resultPromise = new Promise(fulfill => {
+    resultPromise = new Promise(fulfill => {
       fulfillFormatPromise = fulfill;
     });
+    this._formattedPaths.set(path, resultPromise);
+    var content = await uiSourceCode.requestContent();
+    var highlighterType = Bindings.NetworkProject.uiSourceCodeMimeType(uiSourceCode);
     Sources.Formatter.format(uiSourceCode.contentType(), highlighterType, content || '', innerCallback.bind(this));
     return resultPromise;
 
@@ -112,9 +115,6 @@ Sources.SourceFormatter = class {
       this._scriptMapping._setSourceMappingEnabled(formatData, true);
       this._styleMapping._setSourceMappingEnabled(formatData, true);
 
-      var path = formatData.originalPath();
-      this._formattedPaths.set(path, formattedUISourceCode);
-
       for (var decoration of uiSourceCode.allDecorations()) {
         var range = decoration.range();
         var startLocation = formatterMapping.originalToFormatted(range.startLine, range.startColumn);