CRM/Utils/GlobalStack.php

   1 <?php /*
   2  +--------------------------------------------------------------------+
   3  | CiviCRM version 4.4                                                |
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   5  | Copyright CiviCRM LLC (c) 2004-2013                                |
   6  +--------------------------------------------------------------------+
   7  | This file is a part of CiviCRM.                                    |
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   9  | CiviCRM is free software; you can copy, modify, and distribute it  |
  10  | under the terms of the GNU Affero General Public License           |
  11  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  12  |                                                                    |
  13  | CiviCRM is distributed in the hope that it will be useful, but     |
  14  | WITHOUT ANY WARRANTY; without even the implied warranty of         |
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  16  | See the GNU Affero General Public License for more details.        |
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  21  | at info[AT]civicrm[DOT]org. If you have questions about the        |
  22  | GNU Affero General Public License or the licensing of CiviCRM,     |
  23  | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
  24  +--------------------------------------------------------------------+
  25 */
  26
  27 /**
  28  * Temporarily change a global variable.
  29  *
  30  * @code
  31  * $globals = CRM_Utils_GlobalStack::singleton();
  32  * $globals->push(array(
  33  *   '_GET' => array(
  34  *     'q' => 'some-value
  35  *   ),
  36  * ));
  37  * ...do stuff...
  38  * $globals->pop();
  39  * @endcode
  40  *
  41  * Note: for purposes of this class, we'll refer to the array passed into
  42  * push() as a frame.
  43  */
  44 class CRM_Utils_GlobalStack {
  45   /**
  46    * We don't have a container or dependency-injection, so use singleton instead
  47    *
  48    * @var object
  49    * @static
  50    */
  51   private static $_singleton = NULL;
  52
  53   private $backups = array();
  54
  55   /**
  56    * Get or set the single instance of CRM_Utils_GlobalStack
  57    *
  58    * @return CRM_Utils_GlobalStack
  59    */
  60   static public function singleton() {
  61     if (self::$_singleton === NULL) {
  62       self::$_singleton = new CRM_Utils_GlobalStack();
  63     }
  64     return self::$_singleton;
  65   }
  66
  67   public function push($newFrame) {
  68     $this->backups[] = $this->createBackup($newFrame);
  69     $this->applyFrame($newFrame);
  70   }
  71
  72   public function pop() {
  73     $this->applyFrame(array_pop($this->backups));
  74   }
  75
  76   /**
  77    * @param array $new the new, incoming frame
  78    * @return array frame
  79    */
  80   public function createBackup($new) {
  81     $frame = array();
  82     foreach ($new as $globalKey => $values) {
  83       if (is_array($values)) {
  84         foreach ($values as $key => $value) {
  85           $frame[$globalKey][$key] = CRM_Utils_Array::value($key, $GLOBALS[$globalKey]);
  86         }
  87       } else {
  88         $frame[$globalKey] = CRM_Utils_Array::value($globalKey, $GLOBALS);
  89       }
  90     }
  91     return $frame;
  92   }
  93
  94   public function applyFrame($newFrame) {
  95     foreach ($newFrame as $globalKey => $values) {
  96       if (is_array($values)) {
  97         foreach ($values as $key => $value) {
  98           $GLOBALS[$globalKey][$key] = $value;
  99         }
 100       } else {
 101         $GLOBALS[$globalKey] = $values;
 102       }
 103     }
 104   }
 105 }