includes/LinkCache.php

   1 <?php
   2 /**
   3  * Cache for article titles (prefixed DB keys) and ids linked from one source
   4  * @package MediaWiki
   5  */
   6
   7 /**
   8  *
   9  */
  10 # These are used in incrementalSetup()
  11 define ('LINKCACHE_GOOD', 0);
  12 define ('LINKCACHE_BAD', 1);
  13 define ('LINKCACHE_IMAGE', 2);
  14
  15 /**
  16  *
  17  * @package MediaWiki
  18  */
  19 class LinkCache {
  20         // Increment $mClassVer whenever old serialized versions of this class
  21         // becomes incompatible with the new version.
  22         /* private */ var $mClassVer = 2;
  23
  24         /* private */ var $mGoodLinks, $mBadLinks, $mActive;
  25         /* private */ var $mImageLinks, $mCategoryLinks;
  26         /* private */ var $mPreFilled, $mOldGoodLinks, $mOldBadLinks;
  27         /* private */ var $mForUpdate;
  28
  29         /* private */ function getKey( $title ) {
  30                 global $wgDBname;
  31                 return $wgDBname.':lc:title:'.$title;
  32         }
  33
  34         function LinkCache() {
  35                 $this->mActive = true;
  36                 $this->mPreFilled = false;
  37                 $this->mForUpdate = false;
  38                 $this->mGoodLinks = array();
  39                 $this->mBadLinks = array();
  40                 $this->mImageLinks = array();
  41                 $this->mCategoryLinks = array();
  42                 $this->mOldGoodLinks = array();
  43                 $this->mOldBadLinks = array();
  44         }
  45
  46         /**
  47          * General accessor to get/set whether SELECT FOR UPDATE should be used
  48          */
  49         function forUpdate( $update = NULL ) {
  50                 return wfSetVar( $this->mForUpdate, $update );
  51         }
  52
  53         function getGoodLinkID( $title ) {
  54                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  55                         return $this->mGoodLinks[$title];
  56                 } else {
  57                         return 0;
  58                 }
  59         }
  60
  61         function isBadLink( $title ) {
  62                 return array_key_exists( $title, $this->mBadLinks );
  63         }
  64
  65         function addGoodLink( $id, $title ) {
  66                 if ( $this->mActive ) {
  67                         $this->mGoodLinks[$title] = $id;
  68                 }
  69         }
  70
  71         function addBadLink( $title ) {
  72                 if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
  73                         $this->mBadLinks[$title] = 1;
  74                 }
  75         }
  76
  77         function addImageLink( $title ) {
  78                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  79         }
  80
  81         function addImageLinkObj( $nt ) {
  82                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  83         }
  84
  85         function addCategoryLink( $title, $sortkey ) {
  86                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  87         }
  88
  89         function addCategoryLinkObj( &$nt, $sortkey ) {
  90                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
  91         }
  92
  93         function clearBadLink( $title ) {
  94                 unset( $this->mBadLinks[$title] );
  95                 $this->clearLink( $title );
  96         }
  97
  98         function clearLink( $title ) {
  99                 global $wgMemc, $wgLinkCacheMemcached;
 100                 if( $wgLinkCacheMemcached )
 101                         $wgMemc->delete( $this->getKey( $title ) );
 102         }
 103
 104         function suspend() { $this->mActive = false; }
 105         function resume() { $this->mActive = true; }
 106         function getGoodLinks() { return $this->mGoodLinks; }
 107         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 108         function getImageLinks() { return $this->mImageLinks; }
 109         function getCategoryLinks() { return $this->mCategoryLinks; }
 110
 111         function addLink( $title ) {
 112                 $nt = Title::newFromDBkey( $title );
 113                 if( $nt ) {
 114                         return $this->addLinkObj( $nt );
 115                 } else {
 116                         return 0;
 117                 }
 118         }
 119
 120         function addLinkObj( &$nt ) {
 121                 global $wgMemc, $wgLinkCacheMemcached;
 122                 $title = $nt->getPrefixedDBkey();
 123                 if ( $this->isBadLink( $title ) ) { return 0; }
 124                 $id = $this->getGoodLinkID( $title );
 125                 if ( 0 != $id ) { return $id; }
 126
 127                 $fname = 'LinkCache::addLinkObj';
 128                 wfProfileIn( $fname );
 129
 130                 $ns = $nt->getNamespace();
 131                 $t = $nt->getDBkey();
 132
 133                 if ( '' == $title ) {
 134                         wfProfileOut( $fname );
 135                         return 0;
 136                 }
 137
 138                 $id = NULL;
 139                 if( $wgLinkCacheMemcached )
 140                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 141                 if( ! is_integer( $id ) ) {
 142                         if ( $this->mForUpdate ) {
 143                                 $db =& wfGetDB( DB_MASTER );
 144                                 $options = array( 'FOR UPDATE' );
 145                         } else {
 146                                 $db =& wfGetDB( DB_SLAVE );
 147                                 $options = array();
 148                         }
 149
 150                         $id = $db->getField( 'cur', 'cur_id', array( 'cur_namespace' => $ns, 'cur_title' => $t ), $fname, $options );
 151                         if ( !$id ) {
 152                                 $id = 0;
 153                         }
 154                         if( $wgLinkCacheMemcached )
 155                                 $wgMemc->add( $key, $id, 3600*24 );
 156                 }
 157
 158                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 159                 else { $this->addGoodLink( $id, $title ); }
 160                 wfProfileOut( $fname );
 161                 return $id;
 162         }
 163
 164         function preFill( &$fromtitle ) {
 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                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 225         }
 226
 227         function getBadAdditions() {
 228                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 229                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 230                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 231         }
 232
 233         function getImageAdditions() {
 234                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 235         }
 236
 237         function getGoodDeletions() {
 238                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 239         }
 240
 241         function getBadDeletions() {
 242                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 243         }
 244
 245         function getImageDeletions() {
 246                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 247         }
 248
 249         /**
 250          * Parameters:
 251          * @param $which is one of the LINKCACHE_xxx constants
 252          * @param $del,$add are the incremental update arrays which will be filled.
 253          *
 254          * @return Returns whether or not it's worth doing the incremental version.
 255          *
 256          * For example, if [[List of mathematical topics]] was blanked,
 257          * it would take a long, long time to do incrementally.
 258          */
 259         function incrementalSetup( $which, &$del, &$add ) {
 260                 if ( ! $this->mPreFilled ) {
 261                         return false;
 262                 }
 263
 264                 switch ( $which ) {
 265                         case LINKCACHE_GOOD:
 266                                 $old =& $this->mOldGoodLinks;
 267                                 $cur =& $this->mGoodLinks;
 268                                 $del = $this->getGoodDeletions();
 269                                 $add = $this->getGoodAdditions();
 270                                 break;
 271                         case LINKCACHE_BAD:
 272                                 $old =& $this->mOldBadLinks;
 273                                 $cur =& $this->mBadLinks;
 274                                 $del = $this->getBadDeletions();
 275                                 $add = $this->getBadAdditions();
 276                                 break;
 277                         default: # LINKCACHE_IMAGE
 278                                 return false;
 279                 }
 280
 281                 return true;
 282         }
 283
 284         /**
 285          * Clears cache but leaves old preFill copies alone
 286          */
 287         function clear() {
 288                 $this->mGoodLinks = array();
 289                 $this->mBadLinks = array();
 290                 $this->mImageLinks = array();
 291         }
 292
 293         /**
 294          * @access private
 295          */
 296         function fillFromLinkscc( $id ){
 297                 $fname = 'LinkCache::fillFromLinkscc';
 298
 299                 $id = IntVal( $id );
 300                 if ( $this->mForUpdate ) {
 301                         $db =& wfGetDB( DB_MASTER );
 302                         $options = 'FOR UPDATE';
 303                 } else {
 304                         $db =& wfGetDB( DB_SLAVE );
 305                         $options = '';
 306                 }
 307                 $raw = $db->getField( 'linkscc', 'lcc_cacheobj', array( 'lcc_pageid' => $id ), $fname, $options );
 308                 if ( $raw === false ) {
 309                         return false;
 310                 }
 311
 312                 $cacheobj = false;
 313                 if( function_exists( 'gzuncompress' ) )
 314                         $cacheobj = @gzuncompress( $raw );
 315
 316                 if($cacheobj == FALSE){
 317                         $cacheobj = $raw;
 318                 }
 319                 $cc = @unserialize( $cacheobj );
 320                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 321                         $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 322                         $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 323                         $this->mPreFilled = true;
 324                         return TRUE;
 325                 } else {
 326                         return FALSE;
 327                 }
 328
 329         }
 330
 331         /**
 332          * @access private
 333          */
 334         function saveToLinkscc( $pid ){
 335                 global $wgCompressedPersistentLC;
 336                 if( $wgCompressedPersistentLC and function_exists( 'gzcompress' ) ) {
 337                         $ser = gzcompress( serialize( $this ), 3 );
 338                 } else {
 339                         $ser = serialize( $this );
 340                 }
 341                 $db =& wfGetDB( DB_MASTER );
 342                 $db->replace( 'linkscc', array( 'lcc_pageid' ), array( 'lcc_pageid' => $pid, 'lcc_cacheobj' => $ser ) );
 343         }
 344
 345         /**
 346          * Delete linkscc rows which link to here
 347          * @param $pid is a page id
 348          * @static
 349          */
 350         function linksccClearLinksTo( $pid ){
 351                 global $wgEnablePersistentLC;
 352                 if ( $wgEnablePersistentLC ) {
 353                         $fname = 'LinkCache::linksccClearLinksTo';
 354                         $pid = intval( $pid );
 355                         $dbw =& wfGetDB( DB_MASTER );
 356                         # Delete linkscc rows which link to here
 357                         $dbw->deleteJoin( 'linkscc', 'links', 'lcc_pageid', 'l_from', array( 'l_to' => $pid ), $fname );
 358                         # Delete linkscc row representing this page
 359                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ), $fname);
 360                 }
 361
 362         }
 363
 364         /**
 365          * Delete linkscc rows with broken links to here
 366          * @param $title is a prefixed db title for example like Title->getPrefixedDBkey() returns.
 367          * @static
 368          */
 369         function linksccClearBrokenLinksTo( $title ){
 370                 global $wgEnablePersistentLC;
 371                 $fname = 'LinkCache::linksccClearBrokenLinksTo';
 372
 373                 if ( $wgEnablePersistentLC ) {
 374                         $dbw =& wfGetDB( DB_MASTER );
 375                         $dbw->deleteJoin( 'linkscc', 'brokenlinks', 'lcc_pageid', 'bl_from', array( 'bl_to' => $title ), $fname );
 376                 }
 377         }
 378
 379         /**
 380          * @param $pid is a page id
 381          * @static
 382          */
 383         function linksccClearPage( $pid ){
 384                 global $wgEnablePersistentLC;
 385                 if ( $wgEnablePersistentLC ) {
 386                         $pid = intval( $pid );
 387                         $dbw =& wfGetDB( DB_MASTER );
 388                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ) );
 389                 }
 390         }
 391 }
 392 ?>