includes/LinkCache.php

   1 <?
   2 # Cache for article titles and ids linked from one source
   3
   4 # These are used in incrementalSetup()
   5 define ('LINKCACHE_GOOD', 0);
   6 define ('LINKCACHE_BAD', 1);
   7 define ('LINKCACHE_IMAGE', 2);
   8
   9 class LinkCache {
  10         // Increment $mClassVer whenever old serialized versions of this class
  11         // becomes incompatible with the new version.
  12         /* private */ var $mClassVer = 1;
  13
  14         /* private */ var $mGoodLinks, $mBadLinks, $mActive;
  15         /* private */ var $mImageLinks;
  16         /* private */ var $mPreFilled, $mOldGoodLinks, $mOldBadLinks;
  17
  18         /* private */ function getKey( $title ) {
  19                 global $wgDBname;
  20                 return "$wgDBname:lc:title:$title";
  21         }
  22
  23         function LinkCache()
  24         {
  25                 $this->mActive = true;
  26                 $this->mPreFilled = false;
  27                 $this->mGoodLinks = array();
  28                 $this->mBadLinks = array();
  29                 $this->mImageLinks = array();
  30                 $this->mOldGoodLinks = array();
  31                 $this->mOldBadLinks = array();
  32         }
  33
  34         function getGoodLinkID( $title )
  35         {
  36                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  37                         return $this->mGoodLinks[$title];
  38                 } else {
  39                         return 0;
  40                 }
  41         }
  42
  43         function isBadLink( $title )
  44         {
  45                 return array_key_exists( $title, $this->mBadLinks );
  46         }
  47
  48         function addGoodLink( $id, $title )
  49         {
  50                 if ( $this->mActive ) {
  51                         $this->mGoodLinks[$title] = $id;
  52                 }
  53         }
  54
  55         function addBadLink( $title )
  56         {
  57                 if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
  58                         $this->mBadLinks[$title] = 1;
  59                 }
  60         }
  61
  62         function addImageLink( $title )
  63         {
  64                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  65         }
  66
  67         function addImageLinkObj( $nt )
  68         {
  69                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  70         }
  71
  72         function clearBadLink( $title )
  73         {
  74                 unset( $this->mBadLinks[$title] );
  75                 $this->clearLink( $title );
  76         }
  77
  78         function clearLink( $title )
  79         {
  80                 global $wgMemc, $wgLinkCacheMemcached;
  81                 if( $wgLinkCacheMemcached )
  82                         $wgMemc->delete( $this->getKey( $title ) );
  83         }
  84
  85         function suspend() { $this->mActive = false; }
  86         function resume() { $this->mActive = true; }
  87         function getGoodLinks() { return $this->mGoodLinks; }
  88         function getBadLinks() { return array_keys( $this->mBadLinks ); }
  89         function getImageLinks() { return $this->mImageLinks; }
  90
  91         function addLink( $title )
  92         {
  93                 $nt = Title::newFromDBkey( $title );
  94                 if( $nt ) {
  95                         return $this->addLinkObj( $nt );
  96                 } else {
  97                         return 0;
  98                 }
  99         }
 100
 101         function addLinkObj( &$nt )
 102         {
 103                 global $wgMemc, $wgLinkCacheMemcached;
 104
 105                 $title = $nt->getPrefixedDBkey();
 106                 if ( $this->isBadLink( $title ) ) { return 0; }
 107                 $id = $this->getGoodLinkID( $title );
 108                 if ( 0 != $id ) { return $id; }
 109
 110                 $fname = "LinkCache::addLinkObj";
 111                 wfProfileIn( $fname );
 112
 113                 $ns = $nt->getNamespace();
 114                 $t = $nt->getDBkey();
 115
 116                 if ( "" == $title ) {
 117                         wfProfileOut( $fname );
 118                         return 0;
 119                 }
 120
 121                 $id = FALSE;
 122                 if( $wgLinkCacheMemcached )
 123                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 124                 if( $id === FALSE ) {
 125                         $sql = "SELECT cur_id FROM cur WHERE cur_namespace=" .
 126                           "{$ns} AND cur_title='" . wfStrencode( $t ) . "'";
 127                         $res = wfQuery( $sql, DB_READ, "LinkCache::addLink" );
 128
 129                         if ( 0 == wfNumRows( $res ) ) {
 130                                 $id = 0;
 131                         } else {
 132                                 $s = wfFetchObject( $res );
 133                                 $id = $s->cur_id;
 134                         }
 135                         if( $wgLinkCacheMemcached )
 136                                 $wgMemc->add( $key, $id, time()+3600 );
 137                 }
 138
 139                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 140                 else { $this->addGoodLink( $id, $title ); }
 141                 wfProfileOut( $fname );
 142                 return $id;
 143         }
 144
 145         function preFill( &$fromtitle )
 146         {
 147                 global $wgEnablePersistentLC, $wgCompressedPersistentLC;
 148
 149                 $fname = "LinkCache::preFill";
 150                 wfProfileIn( $fname );
 151                 # Note -- $fromtitle is a Title *object*
 152                 $dbkeyfrom = wfStrencode( $fromtitle->getPrefixedDBKey() );
 153
 154                 if ( $wgEnablePersistentLC ) {
 155                         $cc =& $this->getFromLinkscc( $dbkeyfrom );
 156                         if( $cc != FALSE ){
 157                                 $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 158                                 $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 159                                 $this->mPreFilled = true;
 160                                 wfProfileOut( $fname );
 161                                 wfDebug( "LinkCache::preFill - got from linkscc\n" );
 162                                 return;
 163                         }
 164                 }
 165
 166
 167                 $sql = "SELECT cur_id,cur_namespace,cur_title
 168                         FROM cur,links
 169                         WHERE cur_id=l_to AND l_from='{$dbkeyfrom}'";
 170                 $res = wfQuery( $sql, DB_READ, $fname );
 171                 while( $s = wfFetchObject( $res ) ) {
 172                         $this->addGoodLink( $s->cur_id,
 173                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 174                                 );
 175                 }
 176
 177                 $this->suspend();
 178                 $id = $fromtitle->getArticleID();
 179                 $this->resume();
 180
 181                 if( $id == 0 ) {
 182                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 183                         wfProfileOut( $fname );
 184                         return;
 185                 }
 186
 187                 $sql = "SELECT bl_to
 188                         FROM brokenlinks
 189                         WHERE bl_from='{$id}'";
 190                 $res = wfQuery( $sql, DB_READ, "LinkCache::preFill" );
 191                 while( $s = wfFetchObject( $res ) ) {
 192                         $this->addBadLink( $s->bl_to );
 193                 }
 194
 195                 $this->mOldBadLinks = $this->mBadLinks;
 196                 $this->mOldGoodLinks = $this->mGoodLinks;
 197                 $this->mPreFilled = true;
 198
 199                 if ( $wgEnablePersistentLC ) {
 200                         // put fetched link data into cache
 201                         if( $wgCompressedPersistentLC and function_exists( "gzcompress" ) ) {
 202                                 $ser = wfStrencode( gzcompress( serialize( $this ), 3 ));
 203                         } else {
 204                                 $ser = wfStrencode( serialize( $this ) );
 205                         }
 206                         wfQuery("REPLACE INTO linkscc(lcc_pageid,lcc_title,lcc_cacheobj) VALUES({$id}, '{$dbkeyfrom}', '{$ser}')",
 207                                 DB_WRITE);
 208                                 wfDebug( "$fname - saved to linkscc\n" );
 209                 }
 210
 211                 wfProfileOut( $fname );
 212         }
 213
 214         function getGoodAdditions()
 215         {
 216                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 217         }
 218
 219         function getBadAdditions()
 220         {
 221                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 222                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 223                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 224         }
 225
 226         function getImageAdditions()
 227         {
 228                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 229         }
 230
 231         function getGoodDeletions()
 232         {
 233                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 234         }
 235
 236         function getBadDeletions()
 237         {
 238                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 239         }
 240
 241         function getImageDeletions()
 242         {
 243                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 244         }
 245
 246         #     Parameters: $which is one of the LINKCACHE_xxx constants, $del and $add are
 247         # the incremental update arrays which will be filled. Returns whether or not it's
 248         # worth doing the incremental version. For example, if [[List of mathematical topics]]
 249         # was blanked, it would take a long, long time to do incrementally.
 250         function incrementalSetup( $which, &$del, &$add )
 251         {
 252                 if ( ! $this->mPreFilled ) {
 253                         return false;
 254                 }
 255
 256                 switch ( $which ) {
 257                         case LINKCACHE_GOOD:
 258                                 $old =& $this->mOldGoodLinks;
 259                                 $cur =& $this->mGoodLinks;
 260                                 $del = $this->getGoodDeletions();
 261                                 $add = $this->getGoodAdditions();
 262                                 break;
 263                         case LINKCACHE_BAD:
 264                                 $old =& $this->mOldBadLinks;
 265                                 $cur =& $this->mBadLinks;
 266                                 $del = $this->getBadDeletions();
 267                                 $add = $this->getBadAdditions();
 268                                 break;
 269                         default: # LINKCACHE_IMAGE
 270                                 return false;
 271                 }
 272
 273                 return true;
 274         }
 275
 276         # Clears cache but leaves old preFill copies alone
 277         function clear()
 278         {
 279                 $this->mGoodLinks = array();
 280                 $this->mBadLinks = array();
 281                 $this->mImageLinks = array();
 282         }
 283
 284
 285         function &getFromLinkscc( $dbkeyfrom ){
 286                 $res = wfQuery("SELECT lcc_cacheobj FROM linkscc WHERE lcc_title = '{$dbkeyfrom}'",
 287                         DB_READ);
 288                 $row = wfFetchObject( $res );
 289                 if( $row == FALSE)
 290                         return false;
 291
 292                 $cacheobj = false;
 293                 if( function_exists( "gzuncompress" ) )
 294                         $cacheobj = @gzuncompress( $row->lcc_cacheobj );
 295
 296                 if($cacheobj == FALSE){
 297                         $cacheobj = $row->lcc_cacheobj;
 298                 }
 299                 $cc = @unserialize( $cacheobj );
 300                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 301                         return $cc;
 302                 } else {
 303                         return FALSE;
 304                 }
 305         }
 306 }
 307 ?>