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                 $title = $nt->getPrefixedDBkey();
 104                 if ( $this->isBadLink( $title ) ) { return 0; }
 105                 $id = $this->getGoodLinkID( $title );
 106                 if ( 0 != $id ) { return $id; }
 107
 108                 global $wgMemc;
 109                 $fname = "LinkCache::addLinkObj";
 110                 wfProfileIn( $fname );
 111
 112                 $ns = $nt->getNamespace();
 113                 $t = $nt->getDBkey();
 114
 115                 if ( "" == $title ) {
 116                         wfProfileOut( $fname );
 117                         return 0;
 118                 }
 119
 120                 $id = FALSE;
 121                 if( $wgLinkCacheMemcached )
 122                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 123                 if( $id === FALSE ) {
 124                         $sql = "SELECT cur_id FROM cur WHERE cur_namespace=" .
 125                           "{$ns} AND cur_title='" . wfStrencode( $t ) . "'";
 126                         $res = wfQuery( $sql, DB_READ, "LinkCache::addLink" );
 127
 128                         if ( 0 == wfNumRows( $res ) ) {
 129                                 $id = 0;
 130                         } else {
 131                                 $s = wfFetchObject( $res );
 132                                 $id = $s->cur_id;
 133                         }
 134                         if( $wgLinkCacheMemcached )
 135                                 $wgMemc->add( $key, $id, time()+3600 );
 136                 }
 137
 138                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 139                 else { $this->addGoodLink( $id, $title ); }
 140                 wfProfileOut( $fname );
 141                 return $id;
 142         }
 143
 144         function preFill( &$fromtitle )
 145         {
 146                 global $wgEnablePersistentLC, $wgCompressedPersistentLC;
 147
 148                 $fname = "LinkCache::preFill";
 149                 wfProfileIn( $fname );
 150                 # Note -- $fromtitle is a Title *object*
 151                 $dbkeyfrom = wfStrencode( $fromtitle->getPrefixedDBKey() );
 152
 153                 if ( $wgEnablePersistentLC ) {
 154                         $cc =& $this->getFromLinkscc( $dbkeyfrom );
 155                         if( $cc != FALSE ){
 156                                 $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 157                                 $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 158                                 $this->mPreFilled = true;
 159                                 wfProfileOut( $fname );
 160                                 wfDebug( "LinkCache::preFill - got from linkscc\n" );
 161                                 return;
 162                         }
 163                 }
 164
 165
 166                 $sql = "SELECT cur_id,cur_namespace,cur_title
 167                         FROM cur,links
 168                         WHERE cur_id=l_to AND l_from='{$dbkeyfrom}'";
 169                 $res = wfQuery( $sql, DB_READ, $fname );
 170                 while( $s = wfFetchObject( $res ) ) {
 171                         $this->addGoodLink( $s->cur_id,
 172                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 173                                 );
 174                 }
 175
 176                 $this->suspend();
 177                 $id = $fromtitle->getArticleID();
 178                 $this->resume();
 179
 180                 $sql = "SELECT bl_to
 181                         FROM brokenlinks
 182                         WHERE bl_from='{$id}'";
 183                 $res = wfQuery( $sql, DB_READ, "LinkCache::preFill" );
 184                 while( $s = wfFetchObject( $res ) ) {
 185                         $this->addBadLink( $s->bl_to );
 186                 }
 187
 188                 $this->mOldBadLinks = $this->mBadLinks;
 189                 $this->mOldGoodLinks = $this->mGoodLinks;
 190                 $this->mPreFilled = true;
 191
 192                 if ( $wgEnablePersistentLC ) {
 193                         // put fetched link data into cache
 194                         if( $wgCompressedPersistentLC and function_exists( "gzcompress" ) ) {
 195                                 $ser = wfStrencode( gzcompress( serialize( $this ), 3 ));
 196                         } else {
 197                                 $ser = wfStrencode( serialize( $this ) );
 198                         }
 199                         wfQuery("REPLACE INTO linkscc VALUES({$id}, '{$dbkeyfrom}', '{$ser}')",
 200                                 DB_WRITE);
 201                                 wfDebug( "LinkCache::preFill - saved to linkscc\n" );
 202                 }
 203
 204                 wfProfileOut( $fname );
 205         }
 206
 207         function getGoodAdditions()
 208         {
 209                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 210         }
 211
 212         function getBadAdditions()
 213         {
 214                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 215                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 216                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 217         }
 218
 219         function getImageAdditions()
 220         {
 221                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 222         }
 223
 224         function getGoodDeletions()
 225         {
 226                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 227         }
 228
 229         function getBadDeletions()
 230         {
 231                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 232         }
 233
 234         function getImageDeletions()
 235         {
 236                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 237         }
 238
 239         #     Parameters: $which is one of the LINKCACHE_xxx constants, $del and $add are
 240         # the incremental update arrays which will be filled. Returns whether or not it's
 241         # worth doing the incremental version. For example, if [[List of mathematical topics]]
 242         # was blanked, it would take a long, long time to do incrementally.
 243         function incrementalSetup( $which, &$del, &$add )
 244         {
 245                 if ( ! $this->mPreFilled ) {
 246                         return false;
 247                 }
 248
 249                 switch ( $which ) {
 250                         case LINKCACHE_GOOD:
 251                                 $old =& $this->mOldGoodLinks;
 252                                 $cur =& $this->mGoodLinks;
 253                                 $del = $this->getGoodDeletions();
 254                                 $add = $this->getGoodAdditions();
 255                                 break;
 256                         case LINKCACHE_BAD:
 257                                 $old =& $this->mOldBadLinks;
 258                                 $cur =& $this->mBadLinks;
 259                                 $del = $this->getBadDeletions();
 260                                 $add = $this->getBadAdditions();
 261                                 break;
 262                         default: # LINKCACHE_IMAGE
 263                                 return false;
 264                 }
 265
 266                 return true;
 267         }
 268
 269         # Clears cache but leaves old preFill copies alone
 270         function clear()
 271         {
 272                 $this->mGoodLinks = array();
 273                 $this->mBadLinks = array();
 274                 $this->mImageLinks = array();
 275         }
 276
 277
 278         function &getFromLinkscc( $dbkeyfrom ){
 279                 $res = wfQuery("SELECT lcc_cacheobj FROM linkscc WHERE lcc_title = '{$dbkeyfrom}'",
 280                         DB_READ);
 281                 $row = wfFetchObject( $res );
 282                 if( $row == FALSE)
 283                         return false;
 284
 285                 $cacheobj = false;
 286                 if( function_exists( "gzuncompress" ) )
 287                         $cacheobj = @gzuncompress( $row->lcc_cacheobj );
 288
 289                 if($cacheobj == FALSE){
 290                         $cacheobj = $row->lcc_cacheobj;
 291                 }
 292                 $cc = @unserialize( $cacheobj );
 293                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 294                         return $cc;
 295                 } else {
 296                         return FALSE;
 297                 }
 298         }
 299 }
 300 ?>