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          * @param $params array
  19          */
  20         public function __construct( $params ) {
  21                 if ( !isset( $params['caches'] ) ) {
  22                         throw new MWException( __METHOD__.': the caches parameter is required' );
  23                 }
  24
  25                 $this->caches = array();
  26                 foreach ( $params['caches'] as $cacheInfo ) {
  27                         $this->caches[] = ObjectCache::newFromParams( $cacheInfo );
  28                 }
  29         }
  30
  31         public function setDebug( $debug ) {
  32                 $this->doWrite( 'setDebug', $debug );
  33         }
  34
  35         public function get( $key ) {
  36                 foreach ( $this->caches as $cache ) {
  37                         $value = $cache->get( $key );
  38                         if ( $value !== false ) {
  39                                 return $value;
  40                         }
  41                 }
  42                 return false;
  43         }
  44
  45         public function set( $key, $value, $exptime = 0 ) {
  46                 return $this->doWrite( 'set', $key, $value, $exptime );
  47         }
  48
  49         public function delete( $key, $time = 0 ) {
  50                 return $this->doWrite( 'delete', $key, $time );
  51         }
  52
  53         public function add( $key, $value, $exptime = 0 ) {
  54                 return $this->doWrite( 'add', $key, $value, $exptime );
  55         }
  56
  57         public function replace( $key, $value, $exptime = 0 ) {
  58                 return $this->doWrite( 'replace', $key, $value, $exptime );
  59         }
  60
  61         public function incr( $key, $value = 1 ) {
  62                 return $this->doWrite( 'incr', $key, $value );
  63         }
  64
  65         public function decr( $key, $value = 1 ) {
  66                 return $this->doWrite( 'decr', $key, $value );
  67         }
  68
  69         public function lock( $key, $timeout = 0 ) {
  70                 // Lock only the first cache, to avoid deadlocks
  71                 if ( isset( $this->caches[0] ) ) {
  72                         return $this->caches[0]->lock( $key, $timeout );
  73                 } else {
  74                         return true;
  75                 }
  76         }
  77
  78         public function unlock( $key ) {
  79                 if ( isset( $this->caches[0] ) ) {
  80                         return $this->caches[0]->unlock( $key );
  81                 } else {
  82                         return true;
  83                 }
  84         }
  85
  86         protected function doWrite( $method /*, ... */ ) {
  87                 $ret = true;
  88                 $args = func_get_args();
  89                 array_shift( $args );
  90
  91                 foreach ( $this->caches as $cache ) {
  92                         if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
  93                                 $ret = false;
  94                         }
  95                 }
  96                 return $ret;
  97         }
  98
  99         /**
 100          * Delete objects expiring before a certain date.
 101          *
 102          * Succeed if any of the child caches succeed.
 103          * @return bool
 104          */
 105         public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
 106                 $ret = false;
 107                 foreach ( $this->caches as $cache ) {
 108                         if ( $cache->deleteObjectsExpiringBefore( $date, $progressCallback ) ) {
 109                                 $ret = true;
 110                         }
 111                 }
 112                 return $ret;
 113         }
 114 }