CRM/Core/Transaction.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 4.5                                                |
   5  +--------------------------------------------------------------------+
   6  | Copyright CiviCRM LLC (c) 2004-2014                                |
   7  +--------------------------------------------------------------------+
   8  | This file is a part of CiviCRM.                                    |
   9  |                                                                    |
  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
  11  | under the terms of the GNU Affero General Public License           |
  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  13  |                                                                    |
  14  | CiviCRM is distributed in the hope that it will be useful, but     |
  15  | WITHOUT ANY WARRANTY; without even the implied warranty of         |
  16  | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
  17  | See the GNU Affero General Public License for more details.        |
  18  |                                                                    |
  19  | You should have received a copy of the GNU Affero General Public   |
  20  | License and the CiviCRM Licensing Exception along                  |
  21  | with this program; if not, contact CiviCRM LLC                     |
  22  | at info[AT]civicrm[DOT]org. If you have questions about the        |
  23  | GNU Affero General Public License or the licensing of CiviCRM,     |
  24  | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
  25  +--------------------------------------------------------------------+
  26 */
  27
  28 /**
  29  *
  30  * @package CRM
  31  * @copyright CiviCRM LLC (c) 2004-2014
  32  * @copyright David Strauss <david@fourkitchens.com> (c) 2007
  33  * $Id$
  34  *
  35  * This file has its origins in Donald Lobo's conversation with David
  36  * Strauss over IRC and the CRM_Core_DAO::transaction() function.
  37  *
  38  * David went on and abstracted this into a class which can be used in PHP 5
  39  * (since destructors are called automagically at the end of the script).
  40  * Lobo modified the code and used CiviCRM coding standards. David's
  41  * PressFlow Transaction module is available at
  42  * http://drupal.org/project/pressflow_transaction
  43  */
  44 class CRM_Core_Transaction {
  45
  46   /**
  47    * These constants represent phases at which callbacks can be invoked
  48    */
  49   CONST PHASE_PRE_COMMIT = 1;
  50   CONST PHASE_POST_COMMIT = 2;
  51   CONST PHASE_PRE_ROLLBACK = 4;
  52   CONST PHASE_POST_ROLLBACK = 8;
  53
  54   /**
  55    * Keep track of the number of opens and close
  56    *
  57    * @var int
  58    */
  59   private static $_count = 0;
  60
  61   /**
  62    * Keep track if we need to commit or rollback
  63    *
  64    * @var boolean
  65    */
  66   private static $_doCommit = TRUE;
  67
  68   /**
  69    * hold a dao singleton for query operations
  70    *
  71    * @var object
  72    */
  73   private static $_dao = NULL;
  74
  75   /**
  76    * Array of callbacks to invoke when the transaction commits or rolls back.
  77    * Array keys are phase constants.
  78    * Array values are arrays of callbacks.
  79    */
  80   private static $_callbacks = NULL;
  81
  82   /**
  83    * Whether commit() has been called on this instance
  84    * of CRM_Core_Transaction
  85    */
  86   private $_pseudoCommitted = FALSE;
  87
  88   /**
  89    *
  90    */
  91   function __construct() {
  92     if (!self::$_dao) {
  93       self::$_dao = new CRM_Core_DAO();
  94     }
  95
  96     if (self::$_count == 0) {
  97       self::$_dao->query('BEGIN');
  98       self::$_callbacks = array(
  99         self::PHASE_PRE_COMMIT => array(),
 100         self::PHASE_POST_COMMIT => array(),
 101         self::PHASE_PRE_ROLLBACK => array(),
 102         self::PHASE_POST_ROLLBACK => array(),
 103       );
 104     }
 105
 106     self::$_count++;
 107   }
 108
 109   function __destruct() {
 110     $this->commit();
 111   }
 112
 113   function commit() {
 114     if (self::$_count > 0 && !$this->_pseudoCommitted) {
 115       $this->_pseudoCommitted = TRUE;
 116       self::$_count--;
 117
 118       if (self::$_count == 0) {
 119
 120         // It's possible that, say, a POST_COMMIT callback creates another
 121         // transaction. That transaction will need its own list of callbacks.
 122         $oldCallbacks = self::$_callbacks;
 123         self::$_callbacks = NULL;
 124
 125         if (self::$_doCommit) {
 126           self::invokeCallbacks(self::PHASE_PRE_COMMIT, $oldCallbacks);
 127           self::$_dao->query('COMMIT');
 128           self::invokeCallbacks(self::PHASE_POST_COMMIT, $oldCallbacks);
 129         }
 130         else {
 131           self::invokeCallbacks(self::PHASE_PRE_ROLLBACK, $oldCallbacks);
 132           self::$_dao->query('ROLLBACK');
 133           self::invokeCallbacks(self::PHASE_POST_ROLLBACK, $oldCallbacks);
 134         }
 135         // this transaction is complete, so reset doCommit flag
 136         self::$_doCommit = TRUE;
 137       }
 138     }
 139   }
 140
 141   /**
 142    * @param $flag
 143    */
 144   static public function rollbackIfFalse($flag) {
 145     if ($flag === FALSE) {
 146       self::$_doCommit = FALSE;
 147     }
 148   }
 149
 150   public function rollback() {
 151     self::$_doCommit = FALSE;
 152   }
 153
 154   /**
 155    * Force an immediate rollback, regardless of how many any
 156    * CRM_Core_Transaction objects are waiting for
 157    * pseudo-commits.
 158    *
 159    * Only rollback if the transaction API has been called.
 160    *
 161    * This is only appropriate when it is _certain_ that the
 162    * callstack will not wind-down normally -- e.g. before
 163    * a call to exit().
 164    */
 165   static public function forceRollbackIfEnabled() {
 166     if (self::$_count > 0) {
 167       $oldCallbacks = self::$_callbacks;
 168       self::$_callbacks = NULL;
 169       self::invokeCallbacks(self::PHASE_PRE_ROLLBACK, $oldCallbacks);
 170       self::$_dao->query('ROLLBACK');
 171       self::invokeCallbacks(self::PHASE_POST_ROLLBACK, $oldCallbacks);
 172       self::$_count = 0;
 173       self::$_doCommit = TRUE;
 174     }
 175   }
 176
 177   /**
 178    * @return bool
 179    */
 180   static public function willCommit() {
 181     return self::$_doCommit;
 182   }
 183
 184   /**
 185    * Determine whether there is a pending transaction
 186    */
 187   static public function isActive() {
 188     return (self::$_count > 0);
 189   }
 190
 191   /**
 192    * Add a transaction callback
 193    *
 194    * Pre-condition: isActive()
 195    *
 196    * @param $phase A constant; one of: self::PHASE_{PRE,POST}_{COMMIT,ROLLBACK}
 197    * @param $callback A PHP callback
 198    * @param mixed $params Optional values to pass to callback.
 199    *          See php manual call_user_func_array for details.
 200    */
 201   static public function addCallback($phase, $callback, $params = null, $id = NULL) {
 202     if ($id) {
 203       self::$_callbacks[$phase][$id] = array(
 204         'callback' => $callback,
 205         'parameters' => (is_array($params) ? $params : array($params))
 206       );
 207     } else {
 208       self::$_callbacks[$phase][] = array(
 209         'callback' => $callback,
 210         'parameters' => (is_array($params) ? $params : array($params))
 211       );
 212     }
 213   }
 214
 215   /**
 216    * @param $phase
 217    * @param $callbacks
 218    */
 219   static protected function invokeCallbacks($phase, $callbacks) {
 220     if (is_array($callbacks[$phase])) {
 221       foreach ($callbacks[$phase] as $cb) {
 222         call_user_func_array($cb['callback'], $cb['parameters']);
 223       }
 224     }
 225   }
 226 }
 227