SQL Operations Studio Public Preview 1 (0.23) release source code

src/sql/base/common/async.ts

@@ -0,0 +1,83 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import { ITask } from 'vs/base/common/async';
+import { Promise, TPromise, ValueCallback } from 'vs/base/common/winjs.base';
+
+/**
+ * Bases on vscode Delayer, however, it works by only running the task if it gets
+ * a specified number of requests in a specified time
+ *
+ * Ex. Useful encapsulation of handling double click from click listeners
+ */
+export class MultipleRequestDelayer<T> {
+
+	private timeout: number;
+	private completionPromise: Promise;
+	private onSuccess: ValueCallback;
+	private requests: number = 0;
+	private task: ITask<T>;
+
+	constructor(public delay: number, private maxRequests: number = 2) {
+		this.timeout = null;
+		this.completionPromise = null;
+		this.onSuccess = null;
+	}
+
+	trigger(task: ITask<T>): TPromise<T> {
+		this.cancelTimeout();
+		this.task = task;
+
+		if (++this.requests > this.maxRequests - 1) {
+			this.requests = 0;
+			this.onSuccess(null);
+			return this.completionPromise;
+		}
+
+		if (!this.completionPromise) {
+			this.completionPromise = new TPromise((c) => {
+				this.onSuccess = c;
+			}, () => {
+				// no-op
+			}).then(() => {
+				this.completionPromise = null;
+				this.onSuccess = null;
+				const task = this.task;
+				this.task = null;
+
+				return task();
+			});
+		}
+
+		this.timeout = setTimeout(() => {
+			this.timeout = null;
+			this.requests = 0;
+		}, this.delay);
+
+		return this.completionPromise;
+	}
+
+	isTriggered(): boolean {
+		return this.timeout !== null;
+	}
+
+	cancel(): void {
+		this.cancelTimeout();
+
+		if (this.completionPromise) {
+			this.completionPromise.cancel();
+			this.completionPromise = null;
+		}
+	}
+
+	private cancelTimeout(): void {
+		if (this.timeout !== null) {
+			clearTimeout(this.timeout);
+			this.timeout = null;
+		}
+	}
+}