includes/cache/localisation/LCStore.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 /**
  22  * Interface for the persistence layer of LocalisationCache.
  23  *
  24  * The persistence layer is two-level hierarchical cache. The first level
  25  * is the language, the second level is the item or subitem.
  26  *
  27  * Since the data for a whole language is rebuilt in one operation, it needs
  28  * to have a fast and atomic method for deleting or replacing all of the
  29  * current data for a given language. The interface reflects this bulk update
  30  * operation. Callers writing to the cache must first call startWrite(), then
  31  * will call set() a couple of thousand times, then will call finishWrite()
  32  * to commit the operation. When finishWrite() is called, the cache is
  33  * expected to delete all data previously stored for that language.
  34  *
  35  * The values stored are PHP variables suitable for serialize(). Implementations
  36  * of LCStore are responsible for serializing and unserializing.
  37  */
  38 interface LCStore {
  39
  40         /**
  41          * Get a value.
  42          * @param string $code Language code
  43          * @param string $key Cache key
  44          */
  45         function get( $code, $key );
  46
  47         /**
  48          * Start a write transaction.
  49          * @param string $code Language code
  50          */
  51         function startWrite( $code );
  52
  53         /**
  54          * Finish a write transaction.
  55          */
  56         function finishWrite();
  57
  58         /**
  59          * Set a key to a given value. startWrite() must be called before this
  60          * is called, and finishWrite() must be called afterwards.
  61          * @param string $key
  62          * @param mixed $value
  63          */
  64         function set( $key, $value );
  65
  66 }