includes/Interwiki.php

   1 <?php
   2 /**
   3  * @file
   4  * Interwiki table entry
   5  */
   6
   7 /**
   8  * The interwiki class
   9  * All information is loaded on creation when called by Interwiki::fetch( $prefix ).
  10  * All work is done on slave, because this should *never* change (except during schema updates etc, which arent wiki-related)
  11  */
  12 class Interwiki {
  13
  14         // Cache - removed in LRU order when it hits limit
  15         protected static $smCache = array();
  16         const CACHE_LIMIT = 100; // 0 means unlimited, any other value is max number of entries.
  17
  18         protected $mPrefix, $mURL, $mLocal, $mTrans;
  19
  20         function __construct( $prefix = null, $url = '', $local = 0, $trans = 0 )
  21         {
  22                 $this->mPrefix = $prefix;
  23                 $this->mURL = $url;
  24                 $this->mLocal = $local;
  25                 $this->mTrans = $trans;
  26         }
  27
  28         /**
  29          * Fetch an Interwiki object
  30          *
  31          * @return Interwiki Object, or null if not valid
  32          * @param $prefix string Interwiki prefix to use
  33          */
  34         static public function fetch( $prefix ) {
  35                 if( isset( self::$smCache[$prefix] ) ){
  36                         return self::$smCache[$prefix];
  37                 }
  38                 global $wgInterwikiCache;
  39                 if ($wgInterwikiCache) {
  40                         return Interwiki::getInterwikiCached( $key );
  41                 }
  42                 $iw = new Interwiki;
  43                 $iw->load( $prefix );
  44                 if( self::CACHE_LIMIT && count( self::$smCache ) >= self::CACHE_LIMIT ){
  45                         array_shift( self::$smCache );
  46                 }
  47                 self::$smCache[$prefix] = &$iw;
  48                 return $iw;
  49         }
  50
  51         /**
  52          * Fetch interwiki prefix data from local cache in constant database.
  53          *
  54          * @note More logic is explained in DefaultSettings.
  55          *
  56          * @param $key \type{\string} Database key
  57          * @return \type{\string} URL of interwiki site
  58          */
  59         protected static function getInterwikiCached( $key ) {
  60                 global $wgInterwikiCache, $wgInterwikiScopes, $wgInterwikiFallbackSite;
  61                 static $db, $site;
  62
  63                 if (!$db)
  64                         $db=dba_open($wgInterwikiCache,'r','cdb');
  65                 /* Resolve site name */
  66                 if ($wgInterwikiScopes>=3 and !$site) {
  67                         $site = dba_fetch('__sites:' . wfWikiID(), $db);
  68                         if ($site=="")
  69                                 $site = $wgInterwikiFallbackSite;
  70                 }
  71                 $value = dba_fetch( wfMemcKey( $key ), $db);
  72                 if ($value=='' and $wgInterwikiScopes>=3) {
  73                         /* try site-level */
  74                         $value = dba_fetch("_{$site}:{$key}", $db);
  75                 }
  76                 if ($value=='' and $wgInterwikiScopes>=2) {
  77                         /* try globals */
  78                         $value = dba_fetch("__global:{$key}", $db);
  79                 }
  80                 if ($value=='undef')
  81                         $value='';
  82                 $s = new Interwiki( $key );
  83                 if ( $value != '' ) {
  84                         list( $local, $url ) = explode( ' ', $value, 2 );
  85                         $s->mURL = $url;
  86                         $s->mLocal = (int)$local;
  87                 }
  88                 if( self::CACHE_LIMIT && count( self::$smCache ) >= self::CACHE_LIMIT ){
  89                         array_shift( self::$smCache );
  90                 }
  91                 self::$smCache[$prefix] = &$s;
  92                 return $s;
  93         }
  94
  95         /**
  96          * Clear all member variables in the current object. Does not clear
  97          * the block from the DB.
  98          */
  99         function clear() {
 100                 $this->mURL = '';
 101                 $this->mLocal = $this->mTrans = 0;
 102                 $this->mPrefix = null;
 103         }
 104
 105         /**
 106          * Get the DB object
 107          *
 108          * @return Database
 109          */
 110         function &getDB(){
 111                 $db = wfGetDB( DB_SLAVE );
 112                 return $db;
 113         }
 114
 115         /**
 116          * Load interwiki from the DB
 117          *
 118          * @param $prefix The interwiki prefix
 119          * @return bool The prefix is valid
 120          *
 121          */
 122         function load( $prefix ) {
 123                 global $wgMemc;
 124                 $key = wfMemcKey( 'interwiki', $prefix );
 125                 $mc = $wgMemc->get( $key );
 126                 if( $mc ){
 127                         if( $this->loadFromArray( $mc ) ){
 128                                 wfDebug("Succeeded\n");
 129                                 return true;
 130                         }
 131                 }else{
 132                         $db =& $this->getDB();
 133
 134                         $res = $db->resultObject( $db->select( 'interwiki', '*', array( 'iw_prefix' => $prefix ),
 135                                 __METHOD__ ) );
 136                         if ( $this->loadFromResult( $res ) ) {
 137                                 $mc = array( 'url' => $this->mURL, 'local' => $this->mLocal, 'trans' => $this->mTrans );
 138                                 $wgMemc->add( $key, $mc );
 139                                 return true;
 140                         }
 141                 }
 142
 143                 # Give up
 144                 $this->clear();
 145                 return false;
 146         }
 147
 148         /**
 149          * Fill in member variables from an array (e.g. memcached result)
 150          *
 151          * @return bool Whether everything was there
 152          * @param $res ResultWrapper Row from the interwiki table
 153          */
 154         function loadFromArray( $mc ) {
 155                 if( isset( $mc['url'] ) && isset( $mc['local'] ) && isset( $mc['trans'] ) ){
 156                         $this->mURL = $mc['url'];
 157                         $this->mLocal = $mc['local'];
 158                         $this->mTrans = $mc['trans'];
 159                         return true;
 160                 }
 161                 return false;
 162         }
 163
 164         /**
 165          * Fill in member variables from a result wrapper
 166          *
 167          * @return bool Whether there was a row there
 168          * @param $res ResultWrapper Row from the interwiki table
 169          */
 170         function loadFromResult( ResultWrapper $res ) {
 171                 $ret = false;
 172                 if ( 0 != $res->numRows() ) {
 173                         # Get first entry
 174                         $row = $res->fetchObject();
 175                         $this->initFromRow( $row );
 176                         $ret = true;
 177                 }
 178                 $res->free();
 179                 return $ret;
 180         }
 181
 182         /**
 183          * Given a database row from the interwiki table, initialize
 184          * member variables
 185          *
 186          * @param $row ResultWrapper A row from the interwiki table
 187          */
 188         function initFromRow( $row ) {
 189                 $this->mPrefix = $row->iw_prefix;
 190                 $this->mURL = $row->iw_url;
 191                 $this->mLocal = $row->iw_local;
 192                 $this->mTrans = $row->iw_trans;
 193         }
 194
 195         /**
 196          * Get the URL for a particular title (or with $1 if no title given)
 197          *
 198          * @param $title string What text to put for the article name
 199          * @return string The URL
 200          */
 201         function getURL( $title = null ){
 202                 $url = $this->mURL;
 203                 if( $title != null ){
 204                         $url = str_replace( "$1", $title, $url );
 205                 }
 206                 return $url;
 207         }
 208
 209         function isLocal(){
 210                 return $this->mLocal;
 211         }
 212
 213         function isTranscludable(){
 214                 return $this->mTrans;
 215         }
 216
 217 }