CRM/Utils/GlobalStack.php

   1 <?php /*
   2  +--------------------------------------------------------------------+
   3  | Copyright CiviCRM LLC. All rights reserved.                        |
   4  |                                                                    |
   5  | This work is published under the GNU AGPLv3 license with some      |
   6  | permitted exceptions and without any warranty. For full license    |
   7  | and copyright information, see https://civicrm.org/licensing       |
   8  +--------------------------------------------------------------------+
   9  */
  10
  11 /**
  12  *
  13  * @package CRM
  14  * @copyright CiviCRM LLC https://civicrm.org/licensing
  15  */
  16
  17 /**
  18  * Temporarily change a global variable.
  19  *
  20  * @code
  21  * $globals = CRM_Utils_GlobalStack::singleton();
  22  * $globals->push(array(
  23  *   '_GET' => array(
  24  *     'q' => 'some-value
  25  *   ),
  26  * ));
  27  * ...do stuff...
  28  * $globals->pop();
  29  * @endcode
  30  *
  31  * Note: for purposes of this class, we'll refer to the array passed into
  32  * push() as a frame.
  33  */
  34 class CRM_Utils_GlobalStack {
  35   /**
  36    * We don't have a container or dependency-injection, so use singleton instead
  37    *
  38    * @var object
  39    */
  40   private static $_singleton = NULL;
  41
  42   private $backups = [];
  43
  44   /**
  45    * Get or set the single instance of CRM_Utils_GlobalStack.
  46    *
  47    * @return CRM_Utils_GlobalStack
  48    */
  49   public static function singleton() {
  50     if (self::$_singleton === NULL) {
  51       self::$_singleton = new CRM_Utils_GlobalStack();
  52     }
  53     return self::$_singleton;
  54   }
  55
  56   /**
  57    * @param $newFrame
  58    */
  59   public function push($newFrame) {
  60     $this->backups[] = $this->createBackup($newFrame);
  61     $this->applyFrame($newFrame);
  62   }
  63
  64   public function pop() {
  65     $this->applyFrame(array_pop($this->backups));
  66   }
  67
  68   /**
  69    * @param array $new
  70    *   The new, incoming frame.
  71    * @return array
  72    *   frame
  73    */
  74   public function createBackup($new) {
  75     $frame = [];
  76     foreach ($new as $globalKey => $values) {
  77       if (is_array($values)) {
  78         foreach ($values as $key => $value) {
  79           $frame[$globalKey][$key] = CRM_Utils_Array::value($key, $GLOBALS[$globalKey]);
  80         }
  81       }
  82       else {
  83         $frame[$globalKey] = CRM_Utils_Array::value($globalKey, $GLOBALS);
  84       }
  85     }
  86     return $frame;
  87   }
  88
  89   /**
  90    * @param $newFrame
  91    */
  92   public function applyFrame($newFrame) {
  93     foreach ($newFrame as $globalKey => $values) {
  94       if (is_array($values)) {
  95         foreach ($values as $key => $value) {
  96           $GLOBALS[$globalKey][$key] = $value;
  97         }
  98       }
  99       else {
 100         $GLOBALS[$globalKey] = $values;
 101       }
 102     }
 103   }
 104
 105 }