DevTools: support live coverage

third_party/WebKit/Source/devtools/front_end/coverage/CoverageDecorationManager.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.
+
+/**
+ * @typedef {!{
+ *    id: string,
+ *    contentProvider: !Common.ContentProvider,
+ *    line: number,
+ *    column: number
+ * }}
+ */
+Coverage.RawLocation;
+
+Coverage.CoverageDecorationManager = class {
+  /**
+   * @param {!Coverage.CoverageModel} coverageModel
+   */
+  constructor(coverageModel) {
+    this._coverageModel = coverageModel;
+    /** @type {!Map<!Common.ContentProvider, ?TextUtils.Text>} */
+    this._textByProvider = new Map();
+    /** @type {!Multimap<!Common.ContentProvider, !Workspace.UISourceCode>} */
+    this._uiSourceCodeByContentProvider = new Multimap();
+
+    for (var uiSourceCode of Workspace.workspace.uiSourceCodes())
+      uiSourceCode.addLineDecoration(0, Coverage.CoverageDecorationManager._decoratorType, this);
+    Workspace.workspace.addEventListener(Workspace.Workspace.Events.UISourceCodeAdded, this._onUISourceCodeAdded, this);
+  }
+
+  dispose() {
+    for (var uiSourceCode of Workspace.workspace.uiSourceCodes())
+      uiSourceCode.removeDecorationsForType(Coverage.CoverageDecorationManager._decoratorType);
+    Workspace.workspace.removeEventListener(
+        Workspace.Workspace.Events.UISourceCodeAdded, this._onUISourceCodeAdded, this);
+  }
+
+  /**
+   * @param {!Array<!Coverage.CoverageInfo>} updatedEntries
+   */
+  update(updatedEntries) {
+    for (var uiSourceCode of Workspace.workspace.uiSourceCodes()) {
+      uiSourceCode.removeDecorationsForType(Coverage.CoverageDecorationManager._decoratorType);
+      uiSourceCode.addLineDecoration(0, Coverage.CoverageDecorationManager._decoratorType, this);
+    }
+  }
+
+  /**
+   * @param {!Workspace.UISourceCode} uiSourceCode
+   * @return {!Promise<!Array<boolean>>}
+   */
+  async usageByLine(uiSourceCode) {
+    var result = [];
+    var sourceText = new TextUtils.Text(uiSourceCode.content() || '');
+    await this._updateTexts(uiSourceCode, sourceText);
+    var lineEndings = sourceText.lineEndings();
+    for (var line = 0; line < sourceText.lineCount(); ++line) {
+      var lineLength = lineEndings[line] - (line ? lineEndings[line - 1] : 0);
+      var startLocations = this._rawLocationsForSourceLocation(uiSourceCode, line, 0);
+      var endLocations = this._rawLocationsForSourceLocation(uiSourceCode, line, lineLength - 1);
+      var used = false;
+      for (var startIndex = 0, endIndex = 0; startIndex < startLocations.length; ++startIndex) {
+        var start = startLocations[startIndex];
+        while (endIndex < endLocations.length &&
+               Coverage.CoverageDecorationManager._compareLocations(start, endLocations[endIndex]) >= 0)

[alph, 2017/05/05 22:50:36]

Shouldn't be ">" instead?
start === endLocations[endIndex] seems to be a legit range.

+          ++endIndex;
+        if (endIndex >= endLocations.length || endLocations[endIndex].id !== start.id)

[alph, 2017/05/05 22:50:36]

hmm. How come "endLocations[endIndex].id !== start.id)"? Should it be an assert?

+          continue;
+        var end = endLocations[endIndex];
+        var text = this._textByProvider.get(end.contentProvider);
+        if (!text)
+          continue;
+        var textValue = text.value();
+        var startOffset = text.offsetFromPosition(start.line, start.column);
+        var endOffset = text.offsetFromPosition(end.line, end.column);
+        while (startOffset <= endOffset && /\s/.test(textValue[startOffset]))
+          ++startOffset;
+        while (startOffset <= endOffset && /\s/.test(textValue[endOffset]))
+          --endOffset;
+        used =
+            startOffset <= endOffset && this._coverageModel.usageForRange(end.contentProvider, startOffset, endOffset);
+        if (used)
+          break;
+      }
+      result.push(used);
+    }
+    return result;
+  }
+
+  /**
+   * @param {!Workspace.UISourceCode} uiSourceCode
+   * @param {!TextUtils.Text} text
+   * @return {!Promise}
+   */
+  _updateTexts(uiSourceCode, text) {
+    var promises = [];
+    for (var line = 0; line < text.lineCount(); ++line) {
+      for (var entry of this._rawLocationsForSourceLocation(uiSourceCode, line, 0)) {
+        if (this._textByProvider.has(entry.contentProvider))
+          continue;
+        this._textByProvider.set(entry.contentProvider, null);
+        this._uiSourceCodeByContentProvider.set(entry.contentProvider, uiSourceCode);
+        promises.push(this._updateTextForProvider(entry.contentProvider));
+      }
+    }
+    return Promise.all(promises);
+  }
+
+  /**
+   * @param {!Common.ContentProvider} contentProvider
+   * @return {!Promise}
+   */
+  async _updateTextForProvider(contentProvider) {
+    var content = await contentProvider.requestContent();
+    this._textByProvider.set(contentProvider, new TextUtils.Text(content));
+  }
+
+  /**
+   * @param {!Workspace.UISourceCode} uiSourceCode
+   * @param {number} line
+   * @param {number} column
+   * @return {!Array<!Coverage.RawLocation>}
+   */
+  _rawLocationsForSourceLocation(uiSourceCode, line, column) {
+    var result = [];
+    var contentType = uiSourceCode.contentType();
+    if (contentType.hasScripts()) {
+      var location = Bindings.debuggerWorkspaceBinding.uiLocationToRawLocation(uiSourceCode, line, column);
+      if (location && location.script()) {
+        result.push({
+          id: `js:${location.scriptId}`,
+          contentProvider: location.script(),
+          line: location.lineNumber,
+          column: location.columnNumber
+        });
+      }
+    }
+    if (contentType.isStyleSheet() || contentType.isDocument()) {
+      var rawStyleLocations =
+          Bindings.cssWorkspaceBinding.uiLocationToRawLocations(new Workspace.UILocation(uiSourceCode, line, column));
+      for (var location of rawStyleLocations) {
+        if (!location.header())
+          continue;
+        result.push({
+          id: `css:${location.styleSheetId}`,
+          contentProvider: location.header(),
+          line: location.lineNumber,
+          column: location.columnNumber
+        });
+      }
+    }
+    result.sort(Coverage.CoverageDecorationManager._compareLocations);
+    return result;
+  }
+
+  /**
+   * @param {!Coverage.RawLocation} a
+   * @param {!Coverage.RawLocation} b

[alph, 2017/05/05 22:50:36]

@return

+   */
+  static _compareLocations(a, b) {
+    return a.id.localeCompare(b.id) || a.line - b.line || a.column - b.column;
+  }
+
+  /**
+   * @param {!Common.Event} event
+   */
+  _onUISourceCodeAdded(event) {
+    var uiSourceCode = /** @type !Workspace.UISourceCode */ (event.data);
+    uiSourceCode.addLineDecoration(0, Coverage.CoverageDecorationManager._decoratorType, this);
+  }
+};
+
+Coverage.CoverageDecorationManager._decoratorType = 'coverage';
+
+/**
+ * @implements {SourceFrame.UISourceCodeFrame.LineDecorator}
+ */
+Coverage.CoverageView.LineDecorator = class {
+  /**
+   * @override
+   * @param {!Workspace.UISourceCode} uiSourceCode
+   * @param {!TextEditor.CodeMirrorTextEditor} textEditor
+   */
+  decorate(uiSourceCode, textEditor) {
+    var decorations = uiSourceCode.decorationsForType(Coverage.CoverageDecorationManager._decoratorType);
+    if (!decorations.size) {
+      textEditor.uninstallGutter(Coverage.CoverageView.LineDecorator._gutterType);
+      return;
+    }
+    var decorationManager =
+        /** @type {!Coverage.CoverageDecorationManager} */ (decorations.values().next().value.data());
+    decorationManager.usageByLine(uiSourceCode).then(lineUsage => {
+      textEditor.operation(() => this._innerDecorate(textEditor, lineUsage));
+    });
+  }
+
+  /**
+   * @param {!TextEditor.CodeMirrorTextEditor} textEditor
+   * @param {!Array<boolean>} lineUsage
+   */
+  _innerDecorate(textEditor, lineUsage) {
+    var gutterType = Coverage.CoverageView.LineDecorator._gutterType;
+    textEditor.uninstallGutter(gutterType);
+    textEditor.installGutter(gutterType, false);
+    for (var line = 0; line < lineUsage.length; ++line) {
+      var className = lineUsage[line] ? 'text-editor-coverage-used-marker' : 'text-editor-coverage-unused-marker';
+      textEditor.setGutterDecoration(line, gutterType, createElementWithClass('div', className));
+    }
+  }
+};
+
+Coverage.CoverageView.LineDecorator._gutterType = 'CodeMirror-gutter-coverage';