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 in_array( $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                         array_push( $this->mBadLinks, $title );
  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                 $index = array_search( $title, $this->mBadLinks );
  72                 if ( isset( $index ) ) {
  73                         unset( $this->mBadLinks[$index] );
  74                 }
  75                 $this->clearLink( $title );
  76         }
  77
  78         function clearLink( $title ) {
  79                 global $wgMemc;
  80                 $wgMemc->delete( $this->getKey( $title ) );
  81         }
  82
  83         function suspend() { $this->mActive = false; }
  84         function resume() { $this->mActive = true; }
  85         function getGoodLinks() { return $this->mGoodLinks; }
  86         function getBadLinks() { return $this->mBadLinks; }
  87         function getImageLinks() { return $this->mImageLinks; }
  88
  89         function addLink( $title )
  90         {
  91                 $nt = Title::newFromDBkey( $title );
  92                 if( $nt ) {
  93                         return $this->addLinkObj( $nt );
  94                 } else {
  95                         return 0;
  96                 }
  97         }
  98
  99         function addLinkObj( &$nt )
 100         {
 101                 $title = $nt->getPrefixedDBkey();
 102                 if ( $this->isBadLink( $title ) ) { return 0; }
 103                 $id = $this->getGoodLinkID( $title );
 104                 if ( 0 != $id ) { return $id; }
 105
 106                 global $wgMemc;
 107                 $fname = "LinkCache::addLinkObj";
 108                 wfProfileIn( $fname );
 109
 110                 $ns = $nt->getNamespace();
 111                 $t = $nt->getDBkey();
 112
 113                 if ( "" == $title ) {
 114                         wfProfileOut( $fname );
 115                         return 0;
 116                 }
 117
 118                 $id = $wgMemc->get( $key = $this->getKey( $title ) );
 119                 if( $id === FALSE ) {
 120                         $sql = "SELECT cur_id FROM cur WHERE cur_namespace=" .
 121                           "{$ns} AND cur_title='" . wfStrencode( $t ) . "'";
 122                         $res = wfQuery( $sql, DB_READ, "LinkCache::addLink" );
 123
 124                         if ( 0 == wfNumRows( $res ) ) {
 125                                 $id = 0;
 126                         } else {
 127                                 $s = wfFetchObject( $res );
 128                                 $id = $s->cur_id;
 129                         }
 130                         $wgMemc->add( $key, $id, time()+3600 );
 131                 }
 132                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 133                 else { $this->addGoodLink( $id, $title ); }
 134                 wfProfileOut( $fname );
 135                 return $id;
 136         }
 137
 138         function preFill( &$fromtitle )
 139         {
 140                 global $wgEnablePersistentLC;
 141
 142                 $fname = "LinkCache::preFill";
 143                 wfProfileIn( $fname );
 144                 # Note -- $fromtitle is a Title *object*
 145                 $dbkeyfrom = wfStrencode( $fromtitle->getPrefixedDBKey() );
 146
 147                 if ( $wgEnablePersistentLC ) {
 148                         $res = wfQuery("SELECT lcc_cacheobj FROM linkscc WHERE lcc_title = '{$dbkeyfrom}'",
 149                                 DB_READ);
 150                         $row = wfFetchObject( $res );
 151                         if( $row != FALSE){
 152                                 $cacheobj = gzuncompress( $row->lcc_cacheobj );
 153                                 $cc = unserialize( $cacheobj );
 154                                 $this->mGoodLinks = $cc->mGoodLinks;
 155                                 $this->mBadLinks = $cc->mBadLinks;
 156                                 $this->mPreFilled = true;
 157                                 wfProfileOut( $fname );
 158                                 return;
 159                         }
 160                 }
 161
 162
 163                 $sql = "SELECT cur_id,cur_namespace,cur_title
 164                         FROM cur,links
 165                         WHERE cur_id=l_to AND l_from='{$dbkeyfrom}'";
 166                 $res = wfQuery( $sql, DB_READ, $fname );
 167                 while( $s = wfFetchObject( $res ) ) {
 168                         $this->addGoodLink( $s->cur_id,
 169                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 170                                 );
 171                 }
 172
 173                 $this->suspend();
 174                 $id = $fromtitle->getArticleID();
 175                 $this->resume();
 176
 177                 $sql = "SELECT bl_to
 178                         FROM brokenlinks
 179                         WHERE bl_from='{$id}'";
 180                 $res = wfQuery( $sql, DB_READ, "LinkCache::preFill" );
 181                 while( $s = wfFetchObject( $res ) ) {
 182                         $this->addBadLink( $s->bl_to );
 183                 }
 184
 185                 $this->mOldBadLinks = $this->mBadLinks;
 186                 $this->mOldGoodLinks = $this->mGoodLinks;
 187                 $this->mPreFilled = true;
 188
 189                 if ( $wgEnablePersistentLC ) {
 190                         // put fetched link data into cache
 191                         $serCachegz = wfStrencode( gzcompress( serialize( $this ), 3) );
 192                         wfQuery("REPLACE INTO linkscc VALUES({$id}, '{$dbkeyfrom}', '{$serCachegz}')",
 193                                 DB_WRITE);
 194                 }
 195
 196                 wfProfileOut( $fname );
 197         }
 198
 199         function getGoodAdditions()
 200         {
 201                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 202         }
 203
 204         function getBadAdditions()
 205         {
 206                 return array_values( array_diff( $this->mBadLinks, $this->mOldBadLinks ) );
 207         }
 208
 209         function getImageAdditions()
 210         {
 211                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 212         }
 213
 214         function getGoodDeletions()
 215         {
 216                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 217         }
 218
 219         function getBadDeletions()
 220         {
 221                 return array_values( array_diff( $this->mOldBadLinks, $this->mBadLinks ) );
 222         }
 223
 224         function getImageDeletions()
 225         {
 226                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 227         }
 228
 229         #     Parameters: $which is one of the LINKCACHE_xxx constants, $del and $add are
 230         # the incremental update arrays which will be filled. Returns whether or not it's
 231         # worth doing the incremental version. For example, if [[List of mathematical topics]]
 232         # was blanked, it would take a long, long time to do incrementally.
 233         function incrementalSetup( $which, &$del, &$add )
 234         {
 235                 if ( ! $this->mPreFilled ) {
 236                         return false;
 237                 }
 238
 239                 switch ( $which ) {
 240                         case LINKCACHE_GOOD:
 241                                 $old =& $this->mOldGoodLinks;
 242                                 $cur =& $this->mGoodLinks;
 243                                 $del = $this->getGoodDeletions();
 244                                 $add = $this->getGoodAdditions();
 245                                 break;
 246                         case LINKCACHE_BAD:
 247                                 $old =& $this->mOldBadLinks;
 248                                 $cur =& $this->mBadLinks;
 249                                 $del = $this->getBadDeletions();
 250                                 $add = $this->getBadAdditions();
 251                                 break;
 252                         default: # LINKCACHE_IMAGE
 253                                 return false;
 254                 }
 255
 256                 return true;
 257         }
 258
 259         # Clears cache but leaves old preFill copies alone
 260         function clear()
 261         {
 262                 $this->mGoodLinks = array();
 263                 $this->mBadLinks = array();
 264                 $this->mImageLinks = array();
 265         }
 266
 267 }
 268 ?>