includes/LinkCache.php

   1 <?php
   2 # Cache for article titles (prefixed DB keys) 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 = 2;
  13
  14         /* private */ var $mGoodLinks, $mBadLinks, $mActive;
  15         /* private */ var $mImageLinks, $mCategoryLinks;
  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->mCategoryLinks = array();
  31                 $this->mOldGoodLinks = array();
  32                 $this->mOldBadLinks = array();
  33         }
  34
  35         function getGoodLinkID( $title )
  36         {
  37                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  38                         return $this->mGoodLinks[$title];
  39                 } else {
  40                         return 0;
  41                 }
  42         }
  43
  44         function isBadLink( $title )
  45         {
  46                 return array_key_exists( $title, $this->mBadLinks );
  47         }
  48
  49         function addGoodLink( $id, $title )
  50         {
  51                 if ( $this->mActive ) {
  52                         $this->mGoodLinks[$title] = $id;
  53                 }
  54         }
  55
  56         function addBadLink( $title )
  57         {
  58                 if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
  59                         $this->mBadLinks[$title] = 1;
  60                 }
  61         }
  62
  63         function addImageLink( $title )
  64         {
  65                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  66         }
  67
  68         function addImageLinkObj( $nt )
  69         {
  70                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  71         }
  72
  73         function addCategoryLink( $title, $sortkey ) {
  74                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  75         }
  76
  77         function addCategoryLinkObj( &$nt, $sortkey ) {
  78                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
  79         }
  80
  81         function clearBadLink( $title )
  82         {
  83                 unset( $this->mBadLinks[$title] );
  84                 $this->clearLink( $title );
  85         }
  86
  87         function clearLink( $title )
  88         {
  89                 global $wgMemc, $wgLinkCacheMemcached;
  90                 if( $wgLinkCacheMemcached )
  91                         $wgMemc->delete( $this->getKey( $title ) );
  92         }
  93
  94         function suspend() { $this->mActive = false; }
  95         function resume() { $this->mActive = true; }
  96         function getGoodLinks() { return $this->mGoodLinks; }
  97         function getBadLinks() { return array_keys( $this->mBadLinks ); }
  98         function getImageLinks() { return $this->mImageLinks; }
  99         function getCategoryLinks() { return $this->mCategoryLinks; }
 100
 101         function addLink( $title )
 102         {
 103                 $nt = Title::newFromDBkey( $title );
 104                 if( $nt ) {
 105                         return $this->addLinkObj( $nt );
 106                 } else {
 107                         return 0;
 108                 }
 109         }
 110
 111         function addLinkObj( &$nt )
 112         {
 113                 global $wgMemc, $wgLinkCacheMemcached;
 114                 $title = $nt->getPrefixedDBkey();
 115                 if ( $this->isBadLink( $title ) ) { return 0; }
 116                 $id = $this->getGoodLinkID( $title );
 117                 if ( 0 != $id ) { return $id; }
 118
 119                 $fname = "LinkCache::addLinkObj";
 120                 wfProfileIn( $fname );
 121
 122                 $ns = $nt->getNamespace();
 123                 $t = $nt->getDBkey();
 124
 125                 if ( "" == $title ) {
 126                         wfProfileOut( $fname );
 127                         return 0;
 128                 }
 129
 130                 $id = NULL;
 131                 if( $wgLinkCacheMemcached )
 132                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 133                 if( ! is_integer( $id ) ) {
 134                         $sql = "SELECT cur_id FROM cur WHERE cur_namespace=" .
 135                           "{$ns} AND cur_title='" . wfStrencode( $t ) . "'";
 136                         $res = wfQuery( $sql, DB_READ, "LinkCache::addLink" );
 137
 138                         if ( 0 == wfNumRows( $res ) ) {
 139                                 $id = 0;
 140                         } else {
 141                                 $s = wfFetchObject( $res );
 142                                 $id = $s->cur_id;
 143                         }
 144                         if( $wgLinkCacheMemcached )
 145                                 $wgMemc->add( $key, $id, 3600*24 );
 146                 }
 147
 148                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 149                 else { $this->addGoodLink( $id, $title ); }
 150                 wfProfileOut( $fname );
 151                 return $id;
 152         }
 153
 154         function preFill( &$fromtitle )
 155         {
 156                 global $wgEnablePersistentLC;
 157
 158                 $fname = "LinkCache::preFill";
 159                 wfProfileIn( $fname );
 160                 # Note -- $fromtitle is a Title *object*
 161
 162                 $this->suspend();
 163                 $id = $fromtitle->getArticleID();
 164                 $this->resume();
 165
 166                 if( $id == 0 ) {
 167                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 168                         wfProfileOut( $fname );
 169                         return;
 170                 }
 171
 172                 if ( $wgEnablePersistentLC ) {
 173                         if( $this->fillFromLinkscc( $id ) ){
 174                                 return;
 175                         }
 176                 }
 177
 178                 $sql = "SELECT cur_id,cur_namespace,cur_title
 179                         FROM cur,links
 180                         WHERE cur_id=l_to AND l_from=$id";
 181                 $res = wfQuery( $sql, DB_READ, $fname );
 182                 while( $s = wfFetchObject( $res ) ) {
 183                         $this->addGoodLink( $s->cur_id,
 184                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 185                                 );
 186                 }
 187
 188                 $sql = "SELECT bl_to
 189                         FROM brokenlinks
 190                         WHERE bl_from='{$id}'";
 191                 $res = wfQuery( $sql, DB_READ, "LinkCache::preFill" );
 192                 while( $s = wfFetchObject( $res ) ) {
 193                         $this->addBadLink( $s->bl_to );
 194                 }
 195
 196                 $this->mOldBadLinks = $this->mBadLinks;
 197                 $this->mOldGoodLinks = $this->mGoodLinks;
 198                 $this->mPreFilled = true;
 199
 200                 if ( $wgEnablePersistentLC ) {
 201                         $this->saveToLinkscc( $id );
 202                 }
 203                 wfProfileOut( $fname );
 204         }
 205
 206         function getGoodAdditions()
 207         {
 208                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 209         }
 210
 211         function getBadAdditions()
 212         {
 213                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 214                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 215                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 216         }
 217
 218         function getImageAdditions()
 219         {
 220                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 221         }
 222
 223         function getGoodDeletions()
 224         {
 225                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 226         }
 227
 228         function getBadDeletions()
 229         {
 230                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 231         }
 232
 233         function getImageDeletions()
 234         {
 235                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 236         }
 237
 238         #     Parameters: $which is one of the LINKCACHE_xxx constants, $del and $add are
 239         # the incremental update arrays which will be filled. Returns whether or not it's
 240         # worth doing the incremental version. For example, if [[List of mathematical topics]]
 241         # was blanked, it would take a long, long time to do incrementally.
 242         function incrementalSetup( $which, &$del, &$add )
 243         {
 244                 if ( ! $this->mPreFilled ) {
 245                         return false;
 246                 }
 247
 248                 switch ( $which ) {
 249                         case LINKCACHE_GOOD:
 250                                 $old =& $this->mOldGoodLinks;
 251                                 $cur =& $this->mGoodLinks;
 252                                 $del = $this->getGoodDeletions();
 253                                 $add = $this->getGoodAdditions();
 254                                 break;
 255                         case LINKCACHE_BAD:
 256                                 $old =& $this->mOldBadLinks;
 257                                 $cur =& $this->mBadLinks;
 258                                 $del = $this->getBadDeletions();
 259                                 $add = $this->getBadAdditions();
 260                                 break;
 261                         default: # LINKCACHE_IMAGE
 262                                 return false;
 263                 }
 264
 265                 return true;
 266         }
 267
 268         # Clears cache but leaves old preFill copies alone
 269         function clear()
 270         {
 271                 $this->mGoodLinks = array();
 272                 $this->mBadLinks = array();
 273                 $this->mImageLinks = array();
 274         }
 275
 276         /* private */ function fillFromLinkscc( $id ){
 277                 $id = IntVal( $id );
 278                 $res = wfQuery("SELECT lcc_cacheobj FROM linkscc WHERE lcc_pageid = $id",
 279                         DB_READ);
 280                 $row = wfFetchObject( $res );
 281                 if( $row == FALSE)
 282                         return false;
 283
 284                 $cacheobj = false;
 285                 if( function_exists( "gzuncompress" ) )
 286                         $cacheobj = @gzuncompress( $row->lcc_cacheobj );
 287
 288                 if($cacheobj == FALSE){
 289                         $cacheobj = $row->lcc_cacheobj;
 290                 }
 291                 $cc = @unserialize( $cacheobj );
 292                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 293                         $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 294                         $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 295                         $this->mPreFilled = true;
 296                         return TRUE;
 297                 } else {
 298                         return FALSE;
 299                 }
 300
 301         }
 302
 303         /* private */ function saveToLinkscc( $pid ){
 304                 global $wgCompressedPersistentLC;
 305                 if( $wgCompressedPersistentLC and function_exists( "gzcompress" ) ) {
 306                         $ser = wfStrencode( gzcompress( serialize( $this ), 3 ));
 307                 } else {
 308                         $ser = wfStrencode( serialize( $this ) );
 309                 }
 310                 wfQuery("REPLACE INTO linkscc(lcc_pageid,lcc_cacheobj) " .
 311                         "VALUES({$pid}, '{$ser}')", DB_WRITE);
 312         }
 313
 314         # $pid is a page id
 315         /* static */ function linksccClearLinksTo( $pid ){
 316                 $pid = intval( $pid );
 317                 wfQuery("DELETE linkscc FROM linkscc,links ".
 318                         "WHERE lcc_pageid=links.l_from AND l_to={$pid}", DB_WRITE);
 319                 wfQuery("DELETE FROM linkscc WHERE lcc_pageid='{$pid}'", DB_WRITE);
 320         }
 321
 322         # $title is a prefixed db title, for example like Title->getPrefixedDBkey() returns.
 323         /* static */ function linksccClearBrokenLinksTo( $title ){
 324                 $title = wfStrencode( $title );
 325                 wfQuery("DELETE linkscc FROM linkscc,brokenlinks ".
 326                         "WHERE lcc_pageid=bl_from AND bl_to='{$title}'", DB_WRITE);
 327         }
 328
 329         # $pid is a page id
 330         /* static */ function linksccClearPage( $pid ){
 331                 $pid = intval( $pid );
 332                 wfQuery("DELETE FROM linkscc WHERE lcc_pageid='{$pid}'", DB_WRITE);
 333         }
 334 }
 335 ?>