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 addBadLinkObj( &$nt ) {
  78                 $this->addBadLink( $nt->getPrefixedDBkey() );
  79         }
  80
  81         function addImageLink( $title ) {
  82                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  83         }
  84
  85         function addImageLinkObj( $nt ) {
  86                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  87         }
  88
  89         function addCategoryLink( $title, $sortkey ) {
  90                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  91         }
  92
  93         function addCategoryLinkObj( &$nt, $sortkey ) {
  94                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
  95         }
  96
  97         function clearBadLink( $title ) {
  98                 unset( $this->mBadLinks[$title] );
  99                 $this->clearLink( $title );
 100         }
 101
 102         function clearLink( $title ) {
 103                 global $wgMemc, $wgLinkCacheMemcached;
 104                 if( $wgLinkCacheMemcached )
 105                         $wgMemc->delete( $this->getKey( $title ) );
 106         }
 107
 108         function suspend() { $this->mActive = false; }
 109         function resume() { $this->mActive = true; }
 110         function getGoodLinks() { return $this->mGoodLinks; }
 111         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 112         function getImageLinks() { return $this->mImageLinks; }
 113         function getCategoryLinks() { return $this->mCategoryLinks; }
 114
 115         function addLink( $title ) {
 116                 $nt = Title::newFromDBkey( $title );
 117                 if( $nt ) {
 118                         return $this->addLinkObj( $nt );
 119                 } else {
 120                         return 0;
 121                 }
 122         }
 123
 124         function addLinkObj( &$nt ) {
 125                 global $wgMemc, $wgLinkCacheMemcached;
 126                 $title = $nt->getPrefixedDBkey();
 127                 if ( $this->isBadLink( $title ) ) { return 0; }
 128                 $id = $this->getGoodLinkID( $title );
 129                 if ( 0 != $id ) { return $id; }
 130
 131                 $fname = 'LinkCache::addLinkObj';
 132                 wfProfileIn( $fname );
 133
 134                 $ns = $nt->getNamespace();
 135                 $t = $nt->getDBkey();
 136
 137                 if ( '' == $title ) {
 138                         wfProfileOut( $fname );
 139                         return 0;
 140                 }
 141
 142                 $id = NULL;
 143                 if( $wgLinkCacheMemcached )
 144                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 145                 if( ! is_integer( $id ) ) {
 146                         if ( $this->mForUpdate ) {
 147                                 $db =& wfGetDB( DB_MASTER );
 148                                 $options = array( 'FOR UPDATE' );
 149                         } else {
 150                                 $db =& wfGetDB( DB_SLAVE );
 151                                 $options = array();
 152                         }
 153
 154                         $id = $db->selectField( 'cur', 'cur_id', array( 'cur_namespace' => $ns, 'cur_title' => $t ), $fname, $options );
 155                         if ( !$id ) {
 156                                 $id = 0;
 157                         }
 158                         if( $wgLinkCacheMemcached )
 159                                 $wgMemc->add( $key, $id, 3600*24 );
 160                 }
 161
 162                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 163                 else { $this->addGoodLink( $id, $title ); }
 164                 wfProfileOut( $fname );
 165                 return $id;
 166         }
 167
 168         function preFill( &$fromtitle ) {
 169                 global $wgEnablePersistentLC;
 170
 171                 $fname = 'LinkCache::preFill';
 172                 wfProfileIn( $fname );
 173                 # Note -- $fromtitle is a Title *object*
 174
 175                 $this->suspend();
 176                 $id = $fromtitle->getArticleID();
 177                 $this->resume();
 178
 179                 if( $id == 0 ) {
 180                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 181                         wfProfileOut( $fname );
 182                         return;
 183                 }
 184
 185                 if ( $wgEnablePersistentLC ) {
 186                         if( $this->fillFromLinkscc( $id ) ){
 187                                 wfProfileOut( $fname );
 188                                 return;
 189                         }
 190                 }
 191                 if ( $this->mForUpdate ) {
 192                         $db =& wfGetDB( DB_MASTER );
 193                         $options = 'FOR UPDATE';
 194                 } else {
 195                         $db =& wfGetDB( DB_SLAVE );
 196                         $options = '';
 197                 }
 198
 199                 $cur = $db->tableName( 'cur' );
 200                 $links = $db->tableName( 'links' );
 201
 202                 $sql = "SELECT cur_id,cur_namespace,cur_title
 203                         FROM $cur,$links
 204                         WHERE cur_id=l_to AND l_from=$id $options";
 205                 $res = $db->query( $sql, $fname );
 206                 while( $s = $db->fetchObject( $res ) ) {
 207                         $this->addGoodLink( $s->cur_id,
 208                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 209                                 );
 210                 }
 211
 212                 $res = $db->select( 'brokenlinks', array( 'bl_to' ), array( 'bl_from' => $id ), $fname, array( $options ) );
 213                 while( $s = $db->fetchObject( $res ) ) {
 214                         $this->addBadLink( $s->bl_to );
 215                 }
 216
 217                 $this->mOldBadLinks = $this->mBadLinks;
 218                 $this->mOldGoodLinks = $this->mGoodLinks;
 219                 $this->mPreFilled = true;
 220
 221                 if ( $wgEnablePersistentLC ) {
 222                         $this->saveToLinkscc( $id );
 223                 }
 224                 wfProfileOut( $fname );
 225         }
 226
 227         function getGoodAdditions() {
 228                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 229         }
 230
 231         function getBadAdditions() {
 232                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 233                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 234                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 235         }
 236
 237         function getImageAdditions() {
 238                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 239         }
 240
 241         function getGoodDeletions() {
 242                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 243         }
 244
 245         function getBadDeletions() {
 246                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 247         }
 248
 249         function getImageDeletions() {
 250                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 251         }
 252
 253         /**
 254          * Parameters:
 255          * @param $which is one of the LINKCACHE_xxx constants
 256          * @param $del,$add are the incremental update arrays which will be filled.
 257          *
 258          * @return Returns whether or not it's worth doing the incremental version.
 259          *
 260          * For example, if [[List of mathematical topics]] was blanked,
 261          * it would take a long, long time to do incrementally.
 262          */
 263         function incrementalSetup( $which, &$del, &$add ) {
 264                 if ( ! $this->mPreFilled ) {
 265                         return false;
 266                 }
 267
 268                 switch ( $which ) {
 269                         case LINKCACHE_GOOD:
 270                                 $old =& $this->mOldGoodLinks;
 271                                 $cur =& $this->mGoodLinks;
 272                                 $del = $this->getGoodDeletions();
 273                                 $add = $this->getGoodAdditions();
 274                                 break;
 275                         case LINKCACHE_BAD:
 276                                 $old =& $this->mOldBadLinks;
 277                                 $cur =& $this->mBadLinks;
 278                                 $del = $this->getBadDeletions();
 279                                 $add = $this->getBadAdditions();
 280                                 break;
 281                         default: # LINKCACHE_IMAGE
 282                                 return false;
 283                 }
 284
 285                 return true;
 286         }
 287
 288         /**
 289          * Clears cache but leaves old preFill copies alone
 290          */
 291         function clear() {
 292                 $this->mGoodLinks = array();
 293                 $this->mBadLinks = array();
 294                 $this->mImageLinks = array();
 295         }
 296
 297         /**
 298          * @access private
 299          */
 300         function fillFromLinkscc( $id ){
 301                 $fname = 'LinkCache::fillFromLinkscc';
 302
 303                 $id = IntVal( $id );
 304                 if ( $this->mForUpdate ) {
 305                         $db =& wfGetDB( DB_MASTER );
 306                         $options = 'FOR UPDATE';
 307                 } else {
 308                         $db =& wfGetDB( DB_SLAVE );
 309                         $options = '';
 310                 }
 311                 $raw = $db->selectField( 'linkscc', 'lcc_cacheobj', array( 'lcc_pageid' => $id ), $fname, $options );
 312                 if ( $raw === false ) {
 313                         return false;
 314                 }
 315
 316                 $cacheobj = false;
 317                 if( function_exists( 'gzuncompress' ) )
 318                         $cacheobj = @gzuncompress( $raw );
 319
 320                 if($cacheobj == FALSE){
 321                         $cacheobj = $raw;
 322                 }
 323                 $cc = @unserialize( $cacheobj );
 324                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 325                         $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 326                         $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 327                         $this->mPreFilled = true;
 328                         return TRUE;
 329                 } else {
 330                         return FALSE;
 331                 }
 332
 333         }
 334
 335         /**
 336          * @access private
 337          */
 338         function saveToLinkscc( $pid ){
 339                 global $wgCompressedPersistentLC;
 340                 if( $wgCompressedPersistentLC and function_exists( 'gzcompress' ) ) {
 341                         $ser = gzcompress( serialize( $this ), 3 );
 342                 } else {
 343                         $ser = serialize( $this );
 344                 }
 345                 $db =& wfGetDB( DB_MASTER );
 346                 $db->replace( 'linkscc', array( 'lcc_pageid' ), array( 'lcc_pageid' => $pid, 'lcc_cacheobj' => $ser ) );
 347         }
 348
 349         /**
 350          * Delete linkscc rows which link to here
 351          * @param $pid is a page id
 352          * @static
 353          */
 354         function linksccClearLinksTo( $pid ){
 355                 global $wgEnablePersistentLC;
 356                 if ( $wgEnablePersistentLC ) {
 357                         $fname = 'LinkCache::linksccClearLinksTo';
 358                         $pid = intval( $pid );
 359                         $dbw =& wfGetDB( DB_MASTER );
 360                         # Delete linkscc rows which link to here
 361                         $dbw->deleteJoin( 'linkscc', 'links', 'lcc_pageid', 'l_from', array( 'l_to' => $pid ), $fname );
 362                         # Delete linkscc row representing this page
 363                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ), $fname);
 364                 }
 365
 366         }
 367
 368         /**
 369          * Delete linkscc rows with broken links to here
 370          * @param $title is a prefixed db title for example like Title->getPrefixedDBkey() returns.
 371          * @static
 372          */
 373         function linksccClearBrokenLinksTo( $title ){
 374                 global $wgEnablePersistentLC;
 375                 $fname = 'LinkCache::linksccClearBrokenLinksTo';
 376
 377                 if ( $wgEnablePersistentLC ) {
 378                         $dbw =& wfGetDB( DB_MASTER );
 379                         $dbw->deleteJoin( 'linkscc', 'brokenlinks', 'lcc_pageid', 'bl_from', array( 'bl_to' => $title ), $fname );
 380                 }
 381         }
 382
 383         /**
 384          * @param $pid is a page id
 385          * @static
 386          */
 387         function linksccClearPage( $pid ){
 388                 global $wgEnablePersistentLC;
 389                 if ( $wgEnablePersistentLC ) {
 390                         $pid = intval( $pid );
 391                         $dbw =& wfGetDB( DB_MASTER );
 392                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ) );
 393                 }
 394         }
 395 }
 396 ?>