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         /* private */ var $mForUpdate;
  18
  19         /* private */ function getKey( $title ) {
  20                 global $wgDBname;
  21                 return $wgDBname.':lc:title:'.$title;
  22         }
  23
  24         function LinkCache()
  25         {
  26                 $this->mActive = true;
  27                 $this->mPreFilled = false;
  28                 $this->mForUpdate = false;
  29                 $this->mGoodLinks = array();
  30                 $this->mBadLinks = array();
  31                 $this->mImageLinks = array();
  32                 $this->mCategoryLinks = array();
  33                 $this->mOldGoodLinks = array();
  34                 $this->mOldBadLinks = array();
  35         }
  36
  37         # General accessor to get/set whether SELECT FOR UPDATE should be used
  38         function forUpdate( $update = NULL ) {
  39                 return wfSetVar( $this->mForUpdate, $update );
  40         }
  41
  42         function getGoodLinkID( $title )
  43         {
  44                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  45                         return $this->mGoodLinks[$title];
  46                 } else {
  47                         return 0;
  48                 }
  49         }
  50
  51         function isBadLink( $title )
  52         {
  53                 return array_key_exists( $title, $this->mBadLinks );
  54         }
  55
  56         function addGoodLink( $id, $title )
  57         {
  58                 if ( $this->mActive ) {
  59                         $this->mGoodLinks[$title] = $id;
  60                 }
  61         }
  62
  63         function addBadLink( $title )
  64         {
  65                 if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
  66                         $this->mBadLinks[$title] = 1;
  67                 }
  68         }
  69
  70         function addImageLink( $title )
  71         {
  72                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  73         }
  74
  75         function addImageLinkObj( $nt )
  76         {
  77                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  78         }
  79
  80         function addCategoryLink( $title, $sortkey ) {
  81                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  82         }
  83
  84         function addCategoryLinkObj( &$nt, $sortkey ) {
  85                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
  86         }
  87
  88         function clearBadLink( $title )
  89         {
  90                 unset( $this->mBadLinks[$title] );
  91                 $this->clearLink( $title );
  92         }
  93
  94         function clearLink( $title )
  95         {
  96                 global $wgMemc, $wgLinkCacheMemcached;
  97                 if( $wgLinkCacheMemcached )
  98                         $wgMemc->delete( $this->getKey( $title ) );
  99         }
 100
 101         function suspend() { $this->mActive = false; }
 102         function resume() { $this->mActive = true; }
 103         function getGoodLinks() { return $this->mGoodLinks; }
 104         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 105         function getImageLinks() { return $this->mImageLinks; }
 106         function getCategoryLinks() { return $this->mCategoryLinks; }
 107
 108         function addLink( $title )
 109         {
 110                 $nt = Title::newFromDBkey( $title );
 111                 if( $nt ) {
 112                         return $this->addLinkObj( $nt );
 113                 } else {
 114                         return 0;
 115                 }
 116         }
 117
 118         function addLinkObj( &$nt )
 119         {
 120                 global $wgMemc, $wgLinkCacheMemcached;
 121                 $title = $nt->getPrefixedDBkey();
 122                 if ( $this->isBadLink( $title ) ) { return 0; }
 123                 $id = $this->getGoodLinkID( $title );
 124                 if ( 0 != $id ) { return $id; }
 125
 126                 $fname = 'LinkCache::addLinkObj';
 127                 wfProfileIn( $fname );
 128
 129                 $ns = $nt->getNamespace();
 130                 $t = $nt->getDBkey();
 131
 132                 if ( '' == $title ) {
 133                         wfProfileOut( $fname );
 134                         return 0;
 135                 }
 136
 137                 $id = NULL;
 138                 if( $wgLinkCacheMemcached )
 139                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 140                 if( ! is_integer( $id ) ) {
 141                         if ( $this->mForUpdate ) {
 142                                 $db =& wfGetDB( DB_MASTER );
 143                                 $options = array( 'FOR UPDATE' );
 144                         } else {
 145                                 $db =& wfGetDB( DB_SLAVE );
 146                                 $options = array();
 147                         }
 148
 149                         $id = $db->getField( 'cur', 'cur_id', array( 'cur_namespace' => $ns, 'cur_title' => $t ), $fname, $options );
 150                         if ( !$id ) {
 151                                 $id = 0;
 152                         }
 153                         if( $wgLinkCacheMemcached )
 154                                 $wgMemc->add( $key, $id, 3600*24 );
 155                 }
 156
 157                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 158                 else { $this->addGoodLink( $id, $title ); }
 159                 wfProfileOut( $fname );
 160                 return $id;
 161         }
 162
 163         function preFill( &$fromtitle )
 164         {
 165                 global $wgEnablePersistentLC;
 166
 167                 $fname = 'LinkCache::preFill';
 168                 wfProfileIn( $fname );
 169                 # Note -- $fromtitle is a Title *object*
 170
 171                 $this->suspend();
 172                 $id = $fromtitle->getArticleID();
 173                 $this->resume();
 174
 175                 if( $id == 0 ) {
 176                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 177                         wfProfileOut( $fname );
 178                         return;
 179                 }
 180
 181                 if ( $wgEnablePersistentLC ) {
 182                         if( $this->fillFromLinkscc( $id ) ){
 183                                 wfProfileOut( $fname );
 184                                 return;
 185                         }
 186                 }
 187                 if ( $this->mForUpdate ) {
 188                         $db =& wfGetDB( DB_MASTER );
 189                         $options = 'FOR UPDATE';
 190                 } else {
 191                         $db =& wfGetDB( DB_SLAVE );
 192                         $options = '';
 193                 }
 194
 195                 $cur = $db->tableName( 'cur' );
 196                 $links = $db->tableName( 'links' );
 197
 198                 $sql = "SELECT cur_id,cur_namespace,cur_title
 199                         FROM $cur,$links
 200                         WHERE cur_id=l_to AND l_from=$id $options";
 201                 $res = $db->query( $sql, $fname );
 202                 while( $s = $db->fetchObject( $res ) ) {
 203                         $this->addGoodLink( $s->cur_id,
 204                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 205                                 );
 206                 }
 207
 208                 $res = $db->select( 'brokenlinks', array( 'bl_to' ), array( 'bl_from' => $id ), $fname, array( $options ) );
 209                 while( $s = $db->fetchObject( $res ) ) {
 210                         $this->addBadLink( $s->bl_to );
 211                 }
 212
 213                 $this->mOldBadLinks = $this->mBadLinks;
 214                 $this->mOldGoodLinks = $this->mGoodLinks;
 215                 $this->mPreFilled = true;
 216
 217                 if ( $wgEnablePersistentLC ) {
 218                         $this->saveToLinkscc( $id );
 219                 }
 220                 wfProfileOut( $fname );
 221         }
 222
 223         function getGoodAdditions()
 224         {
 225                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 226         }
 227
 228         function getBadAdditions()
 229         {
 230                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 231                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 232                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 233         }
 234
 235         function getImageAdditions()
 236         {
 237                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 238         }
 239
 240         function getGoodDeletions()
 241         {
 242                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 243         }
 244
 245         function getBadDeletions()
 246         {
 247                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 248         }
 249
 250         function getImageDeletions()
 251         {
 252                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 253         }
 254
 255         #     Parameters: $which is one of the LINKCACHE_xxx constants, $del and $add are
 256         # the incremental update arrays which will be filled. Returns whether or not it's
 257         # worth doing the incremental version. For example, if [[List of mathematical topics]]
 258         # was blanked, it would take a long, long time to do incrementally.
 259         function incrementalSetup( $which, &$del, &$add )
 260         {
 261                 if ( ! $this->mPreFilled ) {
 262                         return false;
 263                 }
 264
 265                 switch ( $which ) {
 266                         case LINKCACHE_GOOD:
 267                                 $old =& $this->mOldGoodLinks;
 268                                 $cur =& $this->mGoodLinks;
 269                                 $del = $this->getGoodDeletions();
 270                                 $add = $this->getGoodAdditions();
 271                                 break;
 272                         case LINKCACHE_BAD:
 273                                 $old =& $this->mOldBadLinks;
 274                                 $cur =& $this->mBadLinks;
 275                                 $del = $this->getBadDeletions();
 276                                 $add = $this->getBadAdditions();
 277                                 break;
 278                         default: # LINKCACHE_IMAGE
 279                                 return false;
 280                 }
 281
 282                 return true;
 283         }
 284
 285         # Clears cache but leaves old preFill copies alone
 286         function clear()
 287         {
 288                 $this->mGoodLinks = array();
 289                 $this->mBadLinks = array();
 290                 $this->mImageLinks = array();
 291         }
 292
 293         /* private */ function fillFromLinkscc( $id ){
 294                 $fname = 'LinkCache::fillFromLinkscc';
 295
 296                 $id = IntVal( $id );
 297                 if ( $this->mForUpdate ) {
 298                         $db =& wfGetDB( DB_MASTER );
 299                         $options = 'FOR UPDATE';
 300                 } else {
 301                         $db =& wfGetDB( DB_SLAVE );
 302                         $options = '';
 303                 }
 304                 $raw = $db->getField( 'linkscc', 'lcc_cacheobj', array( 'lcc_pageid' => $id ), $fname, $options );
 305                 if ( $raw === false ) {
 306                         return false;
 307                 }
 308
 309                 $cacheobj = false;
 310                 if( function_exists( 'gzuncompress' ) )
 311                         $cacheobj = @gzuncompress( $raw );
 312
 313                 if($cacheobj == FALSE){
 314                         $cacheobj = $raw;
 315                 }
 316                 $cc = @unserialize( $cacheobj );
 317                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 318                         $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 319                         $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 320                         $this->mPreFilled = true;
 321                         return TRUE;
 322                 } else {
 323                         return FALSE;
 324                 }
 325
 326         }
 327
 328         /* private */ function saveToLinkscc( $pid ){
 329                 global $wgCompressedPersistentLC;
 330                 if( $wgCompressedPersistentLC and function_exists( 'gzcompress' ) ) {
 331                         $ser = gzcompress( serialize( $this ), 3 );
 332                 } else {
 333                         $ser = serialize( $this );
 334                 }
 335                 $db =& wfGetDB( DB_MASTER );
 336                 $db->replace( 'linkscc', array( 'lcc_pageid' ), array( 'lcc_pageid' => $pid, 'lcc_cacheobj' => $ser ) );
 337         }
 338
 339         # Delete linkscc rows which link to here
 340         # $pid is a page id
 341         /* static */ function linksccClearLinksTo( $pid ){
 342                 global $wgEnablePersistentLC;
 343                 if ( $wgEnablePersistentLC ) {
 344                         $fname = 'LinkCache::linksccClearLinksTo';
 345                         $pid = intval( $pid );
 346                         $dbw =& wfGetDB( DB_MASTER );
 347                         # Delete linkscc rows which link to here
 348                         $dbw->deleteJoin( 'linkscc', 'links', 'lcc_pageid', 'l_from', array( 'l_to' => $pid ), $fname );
 349                         # Delete linkscc row representing this page
 350                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ), $fname);
 351                 }
 352
 353         }
 354
 355         # Delete linkscc rows with broken links to here
 356         # $title is a prefixed db title, for example like Title->getPrefixedDBkey() returns.
 357         /* static */ function linksccClearBrokenLinksTo( $title ){
 358                 global $wgEnablePersistentLC;
 359                 $fname = 'LinkCache::linksccClearBrokenLinksTo';
 360
 361                 if ( $wgEnablePersistentLC ) {
 362                         $dbw =& wfGetDB( DB_MASTER );
 363                         $dbw->deleteJoin( 'linkscc', 'brokenlinks', 'lcc_pageid', 'bl_from', array( 'bl_to' => $title ), $fname );
 364                 }
 365         }
 366
 367         # $pid is a page id
 368         /* static */ function linksccClearPage( $pid ){
 369                 global $wgEnablePersistentLC;
 370                 if ( $wgEnablePersistentLC ) {
 371                         $pid = intval( $pid );
 372                         $dbw =& wfGetDB( DB_MASTER );
 373                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ) );
 374                 }
 375         }
 376 }
 377 ?>