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         function LinkCache()
  16         {
  17                 $this->mActive = true;
  18                 $this->mPreFilled = false;
  19                 $this->mGoodLinks = array();
  20                 $this->mBadLinks = array();
  21                 $this->mImageLinks = array();
  22                 $this->mOldGoodLinks = array();
  23                 $this->mOldBadLinks = array();
  24         }
  25
  26         function getGoodLinkID( $title )
  27         {
  28                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  29                         return $this->mGoodLinks[$title];
  30                 } else {
  31                         return 0;
  32                 }
  33         }
  34
  35         function isBadLink( $title )
  36         {
  37                 return in_array( $title, $this->mBadLinks );
  38         }
  39
  40         function addGoodLink( $id, $title )
  41         {
  42                 if ( $this->mActive ) {
  43                         $this->mGoodLinks[$title] = $id;
  44                 }
  45         }
  46
  47         function addBadLink( $title )
  48         {
  49                 if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
  50                         array_push( $this->mBadLinks, $title );
  51                 }
  52         }
  53
  54         function addImageLink( $title )
  55         {
  56                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  57         }
  58
  59         function clearBadLink( $title )
  60         {
  61                 $index = array_search( $title, $this->mBadLinks );
  62                 if ( isset( $index ) ) {
  63                         unset( $this->mBadLinks[$index] );
  64                 }
  65         }
  66
  67         function suspend() { $this->mActive = false; }
  68         function resume() { $this->mActive = true; }
  69         function getGoodLinks() { return $this->mGoodLinks; }
  70         function getBadLinks() { return $this->mBadLinks; }
  71         function getImageLinks() { return $this->mImageLinks; }
  72
  73         function addLink( $title )
  74         {
  75                 if ( $this->isBadLink( $title ) ) { return 0; }
  76                 $id = $this->getGoodLinkID( $title );
  77                 if ( 0 != $id ) { return $id; }
  78
  79                 wfProfileIn( "LinkCache::addLink-checkdatabase" );
  80
  81                 $nt = Title::newFromDBkey( $title );
  82                 $ns = $nt->getNamespace();
  83                 $t = $nt->getDBkey();
  84
  85                 if ( "" == $t ) { return 0; }
  86                 $sql = "SELECT HIGH_PRIORITY cur_id FROM cur WHERE cur_namespace=" .
  87                   "{$ns} AND cur_title='" . wfStrencode( $t ) . "'";
  88                 $res = wfQuery( $sql, "LinkCache::addLink" );
  89
  90                 if ( 0 == wfNumRows( $res ) ) {
  91                         $id = 0;
  92                 } else {
  93                         $s = wfFetchObject( $res );
  94                         $id = $s->cur_id;
  95                 }
  96                 if ( 0 == $id ) { $this->addBadLink( $title ); }
  97                 else { $this->addGoodLink( $id, $title ); }
  98                 wfProfileOut();
  99                 return $id;
 100         }
 101
 102         function preFill( $fromtitle )
 103         {
 104                 wfProfileIn( "LinkCache::preFill" );
 105                 # Note -- $fromtitle is a Title *object*
 106                 $dbkeyfrom = wfStrencode( $fromtitle->getPrefixedDBKey() );
 107                 $sql = "SELECT HIGH_PRIORITY cur_id,cur_namespace,cur_title
 108                         FROM cur,links
 109                         WHERE cur_id=l_to AND l_from='{$dbkeyfrom}'";
 110                 $res = wfQuery( $sql, "LinkCache::preFill" );
 111                 while( $s = wfFetchObject( $res ) ) {
 112                         $this->addGoodLink( $s->cur_id,
 113                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 114                                 );
 115                 }
 116
 117                 $this->suspend();
 118                 $id = $fromtitle->getArticleID();
 119                 $this->resume();
 120
 121                 $sql = "SELECT HIGH_PRIORITY bl_to
 122                         FROM brokenlinks
 123                         WHERE bl_from='{$id}'";
 124                 $res = wfQuery( $sql, "LinkCache::preFill" );
 125                 while( $s = wfFetchObject( $res ) ) {
 126                         $this->addBadLink( $s->bl_to );
 127                 }
 128
 129                 wfDebug("preFill dbkeyfrom=$dbkeyfrom\n");
 130                 $this->mOldBadLinks = $this->mBadLinks;
 131                 $this->mOldGoodLinks = $this->mGoodLinks;
 132                 $this->mPreFilled = true;
 133
 134                 wfProfileOut();
 135         }
 136
 137         function getGoodAdditions()
 138         {
 139                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 140         }
 141
 142         function getBadAdditions()
 143         {
 144                 return array_values( array_diff( $this->mBadLinks, $this->mOldBadLinks ) );
 145         }
 146
 147         function getImageAdditions()
 148         {
 149                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 150         }
 151
 152         function getGoodDeletions()
 153         {
 154                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 155         }
 156
 157         function getBadDeletions()
 158         {
 159                 return array_values( array_diff( $this->mOldBadLinks, $this->mBadLinks ) );
 160         }
 161
 162         function getImageDeletions()
 163         {
 164                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 165         }
 166
 167         #     Parameters: $which is one of the LINKCACHE_xxx constants, $del and $add are
 168         # the incremental update arrays which will be filled. Returns whether or not it's
 169         # worth doing the incremental version. For example, if [[List of mathematical topics]]
 170         # was blanked, it would take a long, long time to do incrementally.
 171         function incrementalSetup( $which, &$del, &$add )
 172         {
 173                 if ( ! $this->mPreFilled ) {
 174                         return false;
 175                 }
 176
 177                 switch ( $which ) {
 178                         case LINKCACHE_GOOD:
 179                                 $old =& $this->mOldGoodLinks;
 180                                 $cur =& $this->mGoodLinks;
 181                                 $del = $this->getGoodDeletions();
 182                                 $add = $this->getGoodAdditions();
 183                                 break;
 184                         case LINKCACHE_BAD:
 185                                 $old =& $this->mOldBadLinks;
 186                                 $cur =& $this->mBadLinks;
 187                                 $del = $this->getBadDeletions();
 188                                 $add = $this->getBadAdditions();
 189                                 break;
 190                         default: # LINKCACHE_IMAGE
 191                                 return false;
 192                 }
 193                 wfDebug( "which = $which\n" );
 194                 wfDebug( '$old = ' . implode(", ", $old) . "\n" );
 195                 wfDebug( '$cur = ' . implode(", ", $cur) . "\n" );
 196                 wfDebug( '$del = ' . implode(", ", $del) . "\n" );
 197                 wfDebug( '$add = ' . implode(", ", $add) . "\n" );
 198
 199                 # Coefficients here (1,1,3,1) could probably be put in a global object
 200                 $timeDumb = count( $old ) + count( $cur );
 201                 $timeIncr = count( $del ) * 3 + count( $new );
 202
 203                 return $timeIncr < $timeDumb;
 204         }
 205
 206         # Clears cache but leaves old preFill copies alone
 207         function clear()
 208         {
 209                 $this->mGoodLinks = array();
 210                 $this->mBadLinks = array();
 211                 $this->mImageLinks = array();
 212         }
 213 }
 214 ?>