feat(dialog): handle dialogs (#212)

src/manualPromise.ts

@@ -0,0 +1,127 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class ManualPromise<T = void> extends Promise<T> {
+  private _resolve!: (t: T) => void;
+  private _reject!: (e: Error) => void;
+  private _isDone: boolean;
+
+  constructor() {
+    let resolve: (t: T) => void;
+    let reject: (e: Error) => void;
+    super((f, r) => {
+      resolve = f;
+      reject = r;
+    });
+    this._isDone = false;
+    this._resolve = resolve!;
+    this._reject = reject!;
+  }
+
+  isDone() {
+    return this._isDone;
+  }
+
+  resolve(t: T) {
+    this._isDone = true;
+    this._resolve(t);
+  }
+
+  reject(e: Error) {
+    this._isDone = true;
+    this._reject(e);
+  }
+
+  static override get [Symbol.species]() {
+    return Promise;
+  }
+
+  override get [Symbol.toStringTag]() {
+    return 'ManualPromise';
+  }
+}
+
+export class LongStandingScope {
+  private _terminateError: Error | undefined;
+  private _closeError: Error | undefined;
+  private _terminatePromises = new Map<ManualPromise<Error>, string[]>();
+  private _isClosed = false;
+
+  reject(error: Error) {
+    this._isClosed = true;
+    this._terminateError = error;
+    for (const p of this._terminatePromises.keys())
+      p.resolve(error);
+  }
+
+  close(error: Error) {
+    this._isClosed = true;
+    this._closeError = error;
+    for (const [p, frames] of this._terminatePromises)
+      p.resolve(cloneError(error, frames));
+  }
+
+  isClosed() {
+    return this._isClosed;
+  }
+
+  static async raceMultiple<T>(scopes: LongStandingScope[], promise: Promise<T>): Promise<T> {
+    return Promise.race(scopes.map(s => s.race(promise)));
+  }
+
+  async race<T>(promise: Promise<T> | Promise<T>[]): Promise<T> {
+    return this._race(Array.isArray(promise) ? promise : [promise], false) as Promise<T>;
+  }
+
+  async safeRace<T>(promise: Promise<T>, defaultValue?: T): Promise<T> {
+    return this._race([promise], true, defaultValue);
+  }
+
+  private async _race(promises: Promise<any>[], safe: boolean, defaultValue?: any): Promise<any> {
+    const terminatePromise = new ManualPromise<Error>();
+    const frames = captureRawStack();
+    if (this._terminateError)
+      terminatePromise.resolve(this._terminateError);
+    if (this._closeError)
+      terminatePromise.resolve(cloneError(this._closeError, frames));
+    this._terminatePromises.set(terminatePromise, frames);
+    try {
+      return await Promise.race([
+        terminatePromise.then(e => safe ? defaultValue : Promise.reject(e)),
+        ...promises
+      ]);
+    } finally {
+      this._terminatePromises.delete(terminatePromise);
+    }
+  }
+}
+
+function cloneError(error: Error, frames: string[]) {
+  const clone = new Error();
+  clone.name = error.name;
+  clone.message = error.message;
+  clone.stack = [error.name + ':' + error.message, ...frames].join('\n');
+  return clone;
+}
+
+function captureRawStack(): string[] {
+  const stackTraceLimit = Error.stackTraceLimit;
+  Error.stackTraceLimit = 50;
+  const error = new Error();
+  const stack = error.stack || '';
+  Error.stackTraceLimit = stackTraceLimit;
+  return stack.split('\n');
+}