perf: check diagnostics in most recently used order

This commit adds an optimization to check diagnostics for open files in most
recently used order.

Author: kyliau

server/src/session.ts

@@ -21,7 +21,7 @@ import {readNgCompletionData, tsCompletionEntryToLspCompletionItem} from './comp
 import {tsDiagnosticToLspDiagnostic} from './diagnostic';
 import {resolveAndRunNgcc} from './ngcc';
 import {ServerHost} from './server_host';
-import {filePathToUri, isConfiguredProject, isDebugMode, lspPositionToTsPosition, lspRangeToTsPositions, tsTextSpanToLspRange, uriToFilePath} from './utils';
+import {filePathToUri, isConfiguredProject, isDebugMode, lspPositionToTsPosition, lspRangeToTsPositions, MruTracker, tsTextSpanToLspRange, uriToFilePath} from './utils';
 import {resolve, Version} from './version_provider';
 
 export interface SessionOptions {
@@ -54,6 +54,7 @@ export class Session {
   private readonly ivy: boolean;
   private readonly configuredProjToExternalProj = new Map<string, string>();
   private readonly logToConsole: boolean;
+  private readonly openFiles = new MruTracker();
   private diagnosticsTimeout: NodeJS.Timeout|null = null;
   private isProjectLoading = false;
   /**
@@ -308,12 +309,9 @@ export class Session {
       // not affect other files because it is local to the Component.
       files.push(file);
     } else {
-      // Get all open files. Cast is needed because the key of the map is
-      // actually ts.Path. See
-      // https://github.com/microsoft/TypeScript/blob/496a1d3caa21c762daa95b1ac1b75823f8774575/src/server/editorServices.ts#L978
-      const openFiles = toArray(this.projectService.openFiles.keys()) as ts.Path[];
-      for (const openFile of openFiles) {
-        const scriptInfo = this.projectService.getScriptInfoForPath(openFile);
+      // Get all open files, most recently used first.
+      for (const openFile of this.openFiles.getAll()) {
+        const scriptInfo = this.projectService.getScriptInfo(openFile);
         if (scriptInfo) {
           files.push(scriptInfo.fileName);
         }
@@ -460,6 +458,7 @@ export class Session {
     if (!filePath) {
       return;
     }
+    this.openFiles.update(filePath);
     // External templates (HTML files) should be tagged as ScriptKind.Unknown
     // so that they don't get parsed as TS files. See
     // https://github.com/microsoft/TypeScript/blob/b217f22e798c781f55d17da72ed099a9dee5c650/src/compiler/program.ts#L1897-L1899
@@ -521,6 +520,7 @@ export class Session {
     if (!filePath) {
       return;
     }
+    this.openFiles.delete(filePath);
     this.projectService.closeClientFile(filePath);
   }
 
@@ -557,6 +557,7 @@ export class Session {
     if (!filePath) {
       return;
     }
+    this.openFiles.update(filePath);
     const scriptInfo = this.projectService.getScriptInfo(filePath);
     if (!scriptInfo) {
       this.error(`Failed to get script info for ${filePath}`);
@@ -582,6 +583,10 @@ export class Session {
   private onDidSaveTextDocument(params: lsp.DidSaveTextDocumentParams) {
     const {text, textDocument} = params;
     const filePath = uriToFilePath(textDocument.uri);
+    if (!filePath) {
+      return;
+    }
+    this.openFiles.update(filePath);
     const scriptInfo = this.projectService.getScriptInfo(filePath);
     if (!scriptInfo) {
       return;

server/src/tests/utils_spec.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {filePathToUri, uriToFilePath} from '../utils';
+import {filePathToUri, MruTracker, uriToFilePath} from '../utils';
 
 describe('filePathToUri', () => {
   it('should return URI with File scheme', () => {
@@ -52,3 +52,40 @@ describe('uriToFilePath', () => {
     });
   }
 });
+
+
+describe('MruTracker', () => {
+  it('should track new items', () => {
+    const tracker = new MruTracker();
+    tracker.update('a');
+    expect(tracker.getAll()).toEqual(['a']);
+  });
+
+  it('should delete existing items', () => {
+    const tracker = new MruTracker();
+    tracker.update('a');
+    tracker.delete('a');
+    expect(tracker.getAll()).toEqual([]);
+  });
+
+  it('should allow deletion of item that does not exist', () => {
+    const tracker = new MruTracker();
+    tracker.delete('a');
+    expect(tracker.getAll()).toEqual([]);
+  });
+
+  it('should return items in most recently used order', () => {
+    const tracker = new MruTracker();
+    tracker.update('a');
+    tracker.update('b');
+    expect(tracker.getAll()).toEqual(['b', 'a']);
+  });
+
+  it('should update existing item', () => {
+    const tracker = new MruTracker();
+    tracker.update('a');
+    tracker.update('b');
+    tracker.update('a');
+    expect(tracker.getAll()).toEqual(['a', 'b']);
+  });
+});

server/src/utils.ts

@@ -81,3 +81,32 @@ export function isConfiguredProject(project: ts.server.Project):
     project is ts.server.ConfiguredProject {
   return project.projectKind === ts.server.ProjectKind.Configured;
 }
+
+/**
+ * A class that tracks items in most recently used order.
+ */
+export class MruTracker {
+  private readonly set = new Set<string>();
+
+  update(item: string) {
+    if (this.set.has(item)) {
+      this.set.delete(item);
+    }
+    this.set.add(item);
+  }
+
+  delete(item: string) {
+    this.set.delete(item);
+  }
+
+  /**
+   * Returns all items sorted by most recently used.
+   */
+  getAll(): string[] {
+    // Javascript Set maintains insertion order, see
+    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
+    // Since items are sorted from least recently used to most recently used,
+    // we reverse the result.
+    return [...this.set].reverse();
+  }
+}