Zabbix

/*

** Zabbix

** Copyright (C) 2001-2022 Zabbix SIA

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU General Public License as published by

** the Free Software Foundation; either version 2 of the License, or

** (at your option) any later version.

**

** This program is distributed in the hope that it will be useful,

** but WITHOUT ANY WARRANTY; without even the implied warranty of

** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

** GNU General Public License for more details.

**

** You should have received a copy of the GNU General Public License

** along with this program; if not, write to the Free Software

** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

**/

​

​

/**

 * A stack implementation for identified overlay objects.

 *

 * @prop {int} length   Overlay collection size.

 * @prop {array} stack  Array of overlay identifiers.

 * @prop {object} map   Overlay objects keyed by their identifiers.

 */

function OverlayCollection() {

    this.stack = [];

    this.map = {};

}

​

Object.defineProperty(OverlayCollection.prototype, 'length', {

    get: function () {

        return this.stack.length;

    },

    writeable: false

});

​

/**

 * Fetches overlay object positioned at top of stack.

 *

 * @return {object|undefined}  Overlay object currently in top of stack.

 */

OverlayCollection.prototype.end = function() {

    return this.getById(this.stack[this.length - 1]);

};

​

/**

 * Retrieve overlay by it's ID.

 *

 * @param {string} id  Overlay identifier.

 *

 * @return {object|undefined}  Overlay object.

 */

OverlayCollection.prototype.getById = function(id) {

    return this.map[id];

};

​

/**

 * Adds new overlay to the stack or, if it already exists, moves it to the top of the stack.

 *

 * @param {object} Overlay object.