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