[clangd] Cleans up the semantic highlighting resources if clangd stops.

Summary: Disposes of the vscode listeners when clangd crashes and reuses the old highlighter when it restarts. The reason for reusing the highlighter is because this way the highlightings will not disappear as we won't have to dispose of them.

Reviewers: hokein, ilya-biryukov

Subscribers: MaskRay, jkorous, arphaman, kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66743

llvm-svn: 370202

clang-tools-extra/clangd/clients/clangd-vscode/src/extension.ts

@@ -112,14 +112,6 @@ export function activate(context: vscode.ExtensionContext) {
   const semanticHighlightingFeature =
       new semanticHighlighting.SemanticHighlightingFeature();
   clangdClient.registerFeature(semanticHighlightingFeature);
-  // The notification handler must be registered after the client is ready or
-  // the client will crash.
-  clangdClient.onReady().then(
-      () => clangdClient.onNotification(
-          semanticHighlighting.NotificationType,
-          semanticHighlightingFeature.handleNotification.bind(
-              semanticHighlightingFeature)));
-
   console.log('Clang Language Server is now active!');
   context.subscriptions.push(clangdClient.start());
   context.subscriptions.push(vscode.commands.registerCommand(
@@ -149,9 +141,14 @@ export function activate(context: vscode.ExtensionContext) {
       clangdClient.onNotification(
           'textDocument/clangd.fileStatus',
           (fileStatus) => { status.onFileUpdated(fileStatus); });
+      clangdClient.onNotification(
+          semanticHighlighting.NotificationType,
+          semanticHighlightingFeature.handleNotification.bind(
+              semanticHighlightingFeature));
     } else if (newState == vscodelc.State.Stopped) {
       // Clear all cached statuses when clangd crashes.
       status.clear();
+      semanticHighlightingFeature.dispose();
     }
   })
   // An empty place holder for the activate command, otherwise we'll get an

clang-tools-extra/clangd/clients/clangd-vscode/src/semantic-highlighting.ts

@@ -56,6 +56,8 @@ export class SemanticHighlightingFeature implements vscodelc.StaticFeature {
   scopeLookupTable: string[][];
   // The object that applies the highlightings clangd sends.
   highlighter: Highlighter;
+  // Any disposables that should be cleaned up when clangd crashes.
+  private subscriptions: vscode.Disposable[] = [];
   fillClientCapabilities(capabilities: vscodelc.ClientCapabilities) {
     // Extend the ClientCapabilities type and add semantic highlighting
     // capability to the object.
@@ -88,14 +90,15 @@ export class SemanticHighlightingFeature implements vscodelc.StaticFeature {
     // otherwise it could try to update the themeRuleMatcher without the
     // highlighter being created.
     this.highlighter = new Highlighter(this.scopeLookupTable);
+    this.subscriptions.push(vscode.Disposable.from(this.highlighter));
     this.loadCurrentTheme();
     // Event handling for handling with TextDocuments/Editors lifetimes.
-    vscode.window.onDidChangeVisibleTextEditors(
+    this.subscriptions.push(vscode.window.onDidChangeVisibleTextEditors(
         (editors: vscode.TextEditor[]) =>
             editors.forEach((e) => this.highlighter.applyHighlights(
-                                e.document.uri.toString())));
-    vscode.workspace.onDidCloseTextDocument(
-        (doc) => this.highlighter.removeFileHighlightings(doc.uri.toString()));
+                                e.document.uri.toString()))));
+    this.subscriptions.push(vscode.workspace.onDidCloseTextDocument(
+        (doc) => this.highlighter.removeFileHighlightings(doc.uri.toString())));
   }
 
   handleNotification(params: SemanticHighlightingParams) {
@@ -103,6 +106,11 @@ export class SemanticHighlightingFeature implements vscodelc.StaticFeature {
         (line) => ({line : line.line, tokens : decodeTokens(line.tokens)}));
     this.highlighter.highlight(params.textDocument.uri, lines);
   }
+  // Disposes of all disposable resources used by this object.
+  public dispose() {
+    this.subscriptions.forEach((d) => d.dispose());
+    this.subscriptions = [];
+  }
 }
 
 // Converts a string of base64 encoded tokens into the corresponding array of
@@ -138,6 +146,13 @@ export class Highlighter {
   constructor(scopeLookupTable: string[][]) {
     this.scopeLookupTable = scopeLookupTable;
   }
+  public dispose() {
+    this.files.clear();
+    this.decorationTypes.forEach((t) => t.dispose());
+    // Dispose must not be not called multiple times if initialize is
+    // called again.
+    this.decorationTypes = [];
+  }
   // This function must be called at least once or no highlightings will be
   // done. Sets the theme that is used when highlighting. Also triggers a
   // recolorization for all current highlighters. Should be called whenever the
@@ -174,6 +189,27 @@ export class Highlighter {
     this.applyHighlights(fileUri);
   }
 
+  // Applies all the highlightings currently stored for a file with fileUri.
+  public applyHighlights(fileUri: string) {
+    if (!this.files.has(fileUri))
+      // There are no highlightings for this file, must return early or will get
+      // out of bounds when applying the decorations below.
+      return;
+    if (!this.decorationTypes.length)
+      // Can't apply any decorations when there is no theme loaded.
+      return;
+    // This must always do a full re-highlighting due to the fact that
+    // TextEditorDecorationType are very expensive to create (which makes
+    // incremental updates infeasible). For this reason one
+    // TextEditorDecorationType is used per scope.
+    const ranges = this.getDecorationRanges(fileUri);
+    vscode.window.visibleTextEditors.forEach((e) => {
+      if (e.document.uri.toString() !== fileUri)
+        return;
+      this.decorationTypes.forEach((d, i) => e.setDecorations(d, ranges[i]));
+    });
+  }
+
   // Called when a text document is closed. Removes any highlighting entries for
   // the text document that was closed.
   public removeFileHighlightings(fileUri: string) {
@@ -207,27 +243,6 @@ export class Highlighter {
     });
     return decorations;
   }
-
-  // Applies all the highlightings currently stored for a file with fileUri.
-  public applyHighlights(fileUri: string) {
-    if (!this.files.has(fileUri))
-      // There are no highlightings for this file, must return early or will get
-      // out of bounds when applying the decorations below.
-      return;
-    if (!this.decorationTypes.length)
-      // Can't apply any decorations when there is no theme loaded.
-      return;
-    // This must always do a full re-highlighting due to the fact that
-    // TextEditorDecorationType are very expensive to create (which makes
-    // incremental updates infeasible). For this reason one
-    // TextEditorDecorationType is used per scope.
-    const ranges = this.getDecorationRanges(fileUri);
-    vscode.window.visibleTextEditors.forEach((e) => {
-      if (e.document.uri.toString() !== fileUri)
-        return;
-      this.decorationTypes.forEach((d, i) => e.setDecorations(d, ranges[i]));
-    });
-  }
 }
 
 // A rule for how to color TextMate scopes.

clang-tools-extra/clangd/clients/clangd-vscode/test/semantic-highlighting.test.ts

@@ -107,7 +107,8 @@ suite('SemanticHighlighting Tests', () => {
     highlighter.highlight('file1', []);
     assert.deepEqual(highlighter.applicationUriHistory, [ 'file1' ]);
     highlighter.initialize(tm);
-    assert.deepEqual(highlighter.applicationUriHistory, [ 'file1', 'file1', 'file2' ]);
+    assert.deepEqual(highlighter.applicationUriHistory,
+                     [ 'file1', 'file1', 'file2' ]);
     // Groups decorations into the scopes used.
     let highlightingsInLine: semanticHighlighting.SemanticHighlightingLine[] = [
       {