azuredatastudio/extensions/mssql/src/objectExplorerNodeProvider/cancelableStream.ts

/*---------------------------------------------------------------------------------------------
 *  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 { Transform } from 'stream';
import * as vscode from 'vscode';
import * as nls from 'vscode-nls';

const localize = nls.loadMessageBundle();

export class CancelableStream extends Transform {
	constructor(private cancelationToken: vscode.CancellationTokenSource) {
		super();
	}

	public _transform(chunk: any, encoding: string, callback: Function): void {
		if (this.cancelationToken && this.cancelationToken.token.isCancellationRequested) {
			callback(new Error(localize('streamCanceled', "Stream operation canceled by the user")));
		} else {
			this.push(chunk);
			callback();
		}
	}
}