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   1  /*
   2  YUI 3.17.2 (build 9c3c78e)
   3  Copyright 2014 Yahoo! Inc. All rights reserved.
   4  Licensed under the BSD License.
   5  http://yuilibrary.com/license/
   6  */
   7  
   8  YUI.add('io-queue', function (Y, NAME) {
   9  
  10  /**
  11  Extends IO to implement Queue for synchronous
  12  transaction processing.
  13  @module io
  14  @submodule io-queue
  15  @for IO
  16  **/
  17  var io = Y.io._map['io:0'] || new Y.IO();
  18  
  19  Y.mix(Y.IO.prototype, {
  20     /**
  21      * Array of transactions queued for processing
  22      *
  23      * @property _q
  24      * @private
  25      * @static
  26      * @type {Object}
  27      */
  28      _q: new Y.Queue(),
  29      _qActiveId: null,
  30      _qInit: false,
  31  
  32     /**
  33      * Property to determine whether the queue is set to
  34      * 1 (active) or 0 (inactive).  When inactive, transactions
  35      * will be stored in the queue until the queue is set to active.
  36      *
  37      * @property _qState
  38      * @private
  39      * @static
  40      * @type {Number}
  41      */
  42      _qState: 1,
  43  
  44     /**
  45      * Method Process the first transaction from the
  46      * queue in FIFO order.
  47      *
  48      * @method _qShift
  49      * @private
  50      * @static
  51      */
  52      _qShift: function() {
  53          var io = this,
  54              o = io._q.next();
  55  
  56          io._qActiveId = o.id;
  57          io._qState = 0;
  58          io.send(o.uri, o.cfg, o.id);
  59      },
  60  
  61     /**
  62      * Method for queueing a transaction before the request is sent to the
  63      * resource, to ensure sequential processing.
  64      *
  65      * @method queue
  66      * @static
  67      * @return {Object}
  68      */
  69      queue: function(uri, c) {
  70          var io = this,
  71              o = { uri: uri, cfg:c, id: this._id++ };
  72  
  73          if(!io._qInit) {
  74              Y.on('io:complete', function(id, o) { io._qNext(id); }, io);
  75              io._qInit = true;
  76          }
  77  
  78          io._q.add(o);
  79          if (io._qState === 1) {
  80              io._qShift();
  81          }
  82  
  83          Y.log('Object queued.  Transaction id is' + o.id, 'info', 'io');
  84          return o;
  85      },
  86  
  87      _qNext: function(id) {
  88          var io = this;
  89          io._qState = 1;
  90          if (io._qActiveId === id && io._q.size() > 0) {
  91              io._qShift();
  92          }
  93      },
  94  
  95     /**
  96      * Method for promoting a transaction to the top of the queue.
  97      *
  98      * @method promote
  99      * @static
 100      */
 101      qPromote: function(o) {
 102          this._q.promote(o);
 103      },
 104  
 105     /**
 106      * Method for removing a specific, pending transaction from
 107      * the queue.
 108      *
 109      * @method remove
 110      * @private
 111      * @static
 112      */
 113      qRemove: function(o) {
 114          this._q.remove(o);
 115      },
 116  
 117     /**
 118      * Method for cancel all pending transaction from
 119      * the queue.
 120      *
 121      * @method empty
 122      * @static
 123      * @since 3.7.3
 124      */
 125      qEmpty: function() {
 126          this._q = new Y.Queue();
 127      },
 128  
 129      qStart: function() {
 130          var io = this;
 131          io._qState = 1;
 132  
 133          if (io._q.size() > 0) {
 134              io._qShift();
 135          }
 136          Y.log('Queue started.', 'info', 'io');
 137      },
 138  
 139     /**
 140      * Method for setting queue processing to inactive.
 141      * Transaction requests to YUI.io.queue() will be stored in the queue, but
 142      * not processed until the queue is reset to "active".
 143      *
 144      * @method _stop
 145      * @private
 146      * @static
 147      */
 148      qStop: function() {
 149          this._qState = 0;
 150          Y.log('Queue stopped.', 'info', 'io');
 151      },
 152  
 153     /**
 154      * Method to query the current size of the queue.
 155      *
 156      * @method _size
 157      * @private
 158      * @static
 159      * @return {Number}
 160      */
 161      qSize: function() {
 162          return this._q.size();
 163      }
 164  
 165  }, true);
 166  
 167  function _queue(u, c) {
 168      return io.queue.apply(io, [u, c]);
 169  }
 170  
 171  _queue.start = function () { io.qStart(); };
 172  _queue.stop = function () { io.qStop(); };
 173  _queue.promote = function (o) { io.qPromote(o); };
 174  _queue.remove = function (o) { io.qRemove(o); };
 175  _queue.size = function () { io.qSize(); };
 176  _queue.empty = function () { io.qEmpty(); };
 177  Y.io.queue = _queue;
 178  
 179  
 180  }, '3.17.2', {"requires": ["io-base", "queue-promote"]});