includes/objectcache/MultiWriteBagOStuff.php

   1 <?php
   2
   3 /**
   4  * A cache class that replicates all writes to multiple child caches. Reads
   5  * are implemented by reading from the caches in the order they are given in
   6  * the configuration until a cache gives a positive result.
   7  */
   8 class MultiWriteBagOStuff extends BagOStuff {
   9         var $caches;
  10
  11         /**
  12          * Constructor. Parameters are:
  13          *
  14          *   - caches:   This should have a numbered array of cache parameter
  15          *               structures, in the style required by $wgObjectCaches. See
  16          *               the documentation of $wgObjectCaches for more detail.
  17          */
  18         public function __construct( $params ) {
  19                 if ( !isset( $params['caches'] ) ) {
  20                         throw new MWException( __METHOD__.': the caches parameter is required' );
  21                 }
  22
  23                 $this->caches = array();
  24                 foreach ( $params['caches'] as $cacheInfo ) {
  25                         $this->caches[] = ObjectCache::newFromParams( $cacheInfo );
  26                 }
  27         }
  28
  29         public function setDebug( $debug ) {
  30                 $this->doWrite( 'setDebug', $debug );
  31         }
  32
  33         public function get( $key ) {
  34                 foreach ( $this->caches as $cache ) {
  35                         $value = $cache->get( $key );
  36                         if ( $value !== false ) {
  37                                 return $value;
  38                         }
  39                 }
  40                 return false;
  41         }
  42
  43         public function set( $key, $value, $exptime = 0 ) {
  44                 return $this->doWrite( 'set', $key, $value, $exptime );
  45         }
  46
  47         public function delete( $key, $time = 0 ) {
  48                 return $this->doWrite( 'delete', $key, $time );
  49         }
  50
  51         public function add( $key, $value, $exptime = 0 ) {
  52                 return $this->doWrite( 'add', $key, $value, $exptime );
  53         }
  54
  55         public function replace( $key, $value, $exptime = 0 ) {
  56                 return $this->doWrite( 'replace', $key, $value, $exptime );
  57         }
  58
  59         public function incr( $key, $value = 1 ) {
  60                 return $this->doWrite( 'incr', $key, $value );
  61         }
  62
  63         public function decr( $key, $value = 1 ) {
  64                 return $this->doWrite( 'decr', $key, $value );
  65         }
  66
  67         public function lock( $key, $timeout = 0 ) {
  68                 // Lock only the first cache, to avoid deadlocks
  69                 if ( isset( $this->caches[0] ) ) {
  70                         return $this->caches[0]->lock( $key, $timeout );
  71                 } else {
  72                         return true;
  73                 }
  74         }
  75
  76         public function unlock( $key ) {
  77                 if ( isset( $this->caches[0] ) ) {
  78                         return $this->caches[0]->unlock( $key );
  79                 } else {
  80                         return true;
  81                 }
  82         }
  83
  84         protected function doWrite( $method /*, ... */ ) {
  85                 $ret = true;
  86                 $args = func_get_args();
  87                 array_shift( $args );
  88
  89                 foreach ( $this->caches as $cache ) {
  90                         $ret = $ret && call_user_func_array( array( $cache, $method ), $args );
  91                 }
  92                 return $ret;
  93         }
  94
  95 }