Use EventEmitter in MultiCancellationToken

Author: aeisenberg

extensions/ql-vscode/src/common/vscode/multi-cancellation-token.ts

@@ -1,28 +1,25 @@
-import { CancellationToken, Disposable } from "vscode";
+import { CancellationToken, Event, EventEmitter } from "vscode";
 
 /**
  * A cancellation token that cancels when any of its constituent
  * cancellation tokens are cancelled.
  */
 export class MultiCancellationToken implements CancellationToken {
   private readonly tokens: CancellationToken[];
+  private readonly onCancellationRequestedEvent = new EventEmitter<void>();
 
   constructor(...tokens: CancellationToken[]) {
     this.tokens = tokens;
+    tokens.forEach((t) =>
+      t.onCancellationRequested(() => this.onCancellationRequestedEvent.fire()),
+    );
   }
 
   get isCancellationRequested(): boolean {
     return this.tokens.some((t) => t.isCancellationRequested);
   }
 
-  onCancellationRequested<T>(listener: (e: T) => any): Disposable {
-    this.tokens.forEach((t) => t.onCancellationRequested(listener));
-    return {
-      dispose: () => {
-        this.tokens.forEach((t) =>
-          t.onCancellationRequested(listener).dispose(),
-        );
-      },
-    };
+  get onCancellationRequested(): Event<any> {
+    return this.onCancellationRequestedEvent.event;
   }
 }