includes/BlockCache.php

   1 <?php
   2 /**
   3  * Contain the blockcache class
   4  */
   5
   6 /**
   7  * Object for fast lookup of IP blocks
   8  * Represents a memcached value, and in some sense, the entire ipblocks table
   9  */
  10 class BlockCache
  11 {
  12         var $mData = false, $mMemcKey;
  13
  14         function BlockCache( $deferLoad = false, $dbName = '' ) {
  15                 global $wgDBname;
  16
  17                 if ( $dbName == '' ) {
  18                         $dbName = $wgDBname;
  19                 }
  20
  21                 $this->mMemcKey = $dbName.':ipblocks';
  22
  23                 if ( !$deferLoad ) {
  24                         $this->load();
  25                 }
  26         }
  27
  28         # Load the blocks from the database and save them to memcached
  29         function loadFromDB() {
  30                 global $wgUseMemCached, $wgMemc;
  31                 $this->mData = array();
  32                 # Selecting FOR UPDATE is a convenient way to serialise the memcached and DB operations,
  33                 # which is necessary even though we don't update the DB
  34                 if ( $wgUseMemCached ) {
  35                         Block::enumBlocks( 'wfBlockCacheInsert', '', EB_FOR_UPDATE );
  36                         $wgMemc->set( $this->mMemcKey, $this->mData, 0 );
  37                 } else {
  38                         Block::enumBlocks( 'wfBlockCacheInsert', '' );
  39                 }
  40         }
  41
  42         # Load the cache from memcached or, if that's not possible, from the DB
  43         function load() {
  44                 global $wgUseMemCached, $wgMemc;
  45
  46                 if ( $this->mData === false) {
  47                         # Try memcached
  48                         if ( $wgUseMemCached ) {
  49                                 $this->mData = $wgMemc->get( $this->mMemcKey );
  50                         }
  51
  52                         if ( !is_array( $this->mData ) ) {
  53                                 $this->loadFromDB();
  54                         }
  55                 }
  56         }
  57
  58         # Add a block to the cache
  59         function insert( &$block ) {
  60                 if ( $block->mUser == 0 ) {
  61                         $nb = $block->getNetworkBits();
  62                         $ipint = $block->getIntegerAddr();
  63                         $index = $ipint >> ( 32 - $nb );
  64
  65                         if ( !array_key_exists( $nb, $this->mData ) ) {
  66                                 $this->mData[$nb] = array();
  67                         }
  68
  69                         $this->mData[$nb][$index] = 1;
  70                 }
  71         }
  72
  73         # Find out if a given IP address is blocked
  74         function get( $ip ) {
  75                 $this->load();
  76                 $ipint = ip2long( $ip );
  77                 $blocked = false;
  78
  79                 foreach ( $this->mData as $networkBits => $blockInts ) {
  80                         if ( array_key_exists( $ipint >> ( 32 - $networkBits ), $blockInts ) ) {
  81                                 $blocked = true;
  82                                 break;
  83                         }
  84                 }
  85                 if ( $blocked ) {
  86                         # Clear low order bits
  87                         if ( $networkBits != 32 ) {
  88                                 $ip .= '/'.$networkBits;
  89                                 $ip = Block::normaliseRange( $ip );
  90                         }
  91                         $block = new Block();
  92                         $block->load( $ip );
  93                 } else {
  94                         $block = false;
  95                 }
  96
  97                 return $block;
  98         }
  99
 100         # Clear the local cache
 101         # There was once a clear() to clear memcached too, but I deleted it
 102         function clearLocal() {
 103                 $this->mData = false;
 104         }
 105 }
 106
 107 function wfBlockCacheInsert( $block, $tag ) {
 108         global $wgBlockCache;
 109         $wgBlockCache->insert( $block );
 110 }