src/third_party/WebKit/Source/devtools/front_end/common/Lock.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @constructor
   7  * @extends {WebInspector.Object}
   8  */
   9 WebInspector.Lock = function()
  10 {
  11     this._count = 0; // Reentrant.
  12 }
  13
  14 /**
  15  * @enum {string}
  16  */
  17 WebInspector.Lock.Events = {
  18     StateChanged: "StateChanged"
  19 }
  20
  21 WebInspector.Lock.prototype = {
  22     /**
  23      * @return {boolean}
  24      */
  25     isAcquired: function()
  26     {
  27         return !!this._count;
  28     },
  29
  30     acquire: function()
  31     {
  32         if (++this._count === 1)
  33             this.dispatchEventToListeners(WebInspector.Lock.Events.StateChanged);
  34     },
  35
  36     release: function()
  37     {
  38         --this._count;
  39         if (this._count < 0) {
  40             console.error("WebInspector.Lock acquire/release calls are unbalanced " + new Error().stack);
  41             return;
  42         }
  43         if (!this._count)
  44             this.dispatchEventToListeners(WebInspector.Lock.Events.StateChanged);
  45     },
  46
  47     __proto__: WebInspector.Object.prototype
  48 }