/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
'use strict';
import Event, { Emitter } from './event';
var shortcutEvent = Object.freeze(function (callback, context) {
    var handle = setTimeout(callback.bind(context), 0);
    return { dispose: function () { clearTimeout(handle); } };
});
export var CancellationToken;
(function (CancellationToken) {
    CancellationToken.None = Object.freeze({
        isCancellationRequested: false,
        onCancellationRequested: Event.None
    });
    CancellationToken.Cancelled = Object.freeze({
        isCancellationRequested: true,
        onCancellationRequested: shortcutEvent
    });
})(CancellationToken || (CancellationToken = {}));
var MutableToken = /** @class */ (function () {
    function MutableToken() {
        this._isCancelled = false;
    }
    MutableToken.prototype.cancel = function () {
        if (!this._isCancelled) {
            this._isCancelled = true;
            if (this._emitter) {
                this._emitter.fire(undefined);
                this._emitter = undefined;
            }
        }
    };
    Object.defineProperty(MutableToken.prototype, "isCancellationRequested", {
        get: function () {
            return this._isCancelled;
        },
        enumerable: true,
        configurable: true
    });
    Object.defineProperty(MutableToken.prototype, "onCancellationRequested", {
        get: function () {
            if (this._isCancelled) {
                return shortcutEvent;
            }
            if (!this._emitter) {
                this._emitter = new Emitter();
            }
            return this._emitter.event;
        },
        enumerable: true,
        configurable: true
    });
    return MutableToken;
}());
var CancellationTokenSource = /** @class */ (function () {
    function CancellationTokenSource() {
    }
    Object.defineProperty(CancellationTokenSource.prototype, "token", {
        get: function () {
            if (!this._token) {
                // be lazy and create the token only when
                // actually needed
                this._token = new MutableToken();
            }
            return this._token;
        },
        enumerable: true,
        configurable: true
    });
    CancellationTokenSource.prototype.cancel = function () {
        if (!this._token) {
            // save an object by returning the default
            // cancelled token when cancellation happens
            // before someone asks for the token
            this._token = CancellationToken.Cancelled;
        }
        else if (this._token instanceof MutableToken) {
            // actually cancel
            this._token.cancel();
        }
    };
    CancellationTokenSource.prototype.dispose = function () {
        this.cancel();
    };
    return CancellationTokenSource;
}());
export { CancellationTokenSource };
