includes/LinkCache.php

   1 <?php
   2 /**
   3  * Cache for article titles (prefixed DB keys) and ids linked from one source
   4  * @package MediaWiki
   5  * @subpackage Cache
   6  */
   7
   8 /**
   9  *
  10  */
  11 # These are used in incrementalSetup()
  12 define ('LINKCACHE_GOOD', 0);
  13 define ('LINKCACHE_BAD', 1);
  14 define ('LINKCACHE_IMAGE', 2);
  15 define ('LINKCACHE_PAGE', 3);
  16
  17 /**
  18  * @package MediaWiki
  19  * @subpackage Cache
  20  */
  21 class LinkCache {
  22         // Increment $mClassVer whenever old serialized versions of this class
  23         // becomes incompatible with the new version.
  24         /* private */ var $mClassVer = 3;
  25
  26         /* private */ var $mPageLinks;
  27         /* private */ var $mGoodLinks, $mBadLinks, $mActive;
  28         /* private */ var $mImageLinks, $mCategoryLinks;
  29         /* private */ var $mPreFilled, $mOldGoodLinks, $mOldBadLinks;
  30         /* private */ var $mForUpdate;
  31
  32         /* private */ function getKey( $title ) {
  33                 global $wgDBname;
  34                 return $wgDBname.':lc:title:'.$title;
  35         }
  36
  37         function LinkCache() {
  38                 $this->mActive = true;
  39                 $this->mPreFilled = false;
  40                 $this->mForUpdate = false;
  41                 $this->mPageLinks = array();
  42                 $this->mGoodLinks = array();
  43                 $this->mBadLinks = array();
  44                 $this->mImageLinks = array();
  45                 $this->mCategoryLinks = array();
  46                 $this->mOldGoodLinks = array();
  47                 $this->mOldBadLinks = array();
  48                 $this->mOldPageLinks = array();
  49         }
  50
  51         /**
  52          * General accessor to get/set whether SELECT FOR UPDATE should be used
  53          */
  54         function forUpdate( $update = NULL ) {
  55                 return wfSetVar( $this->mForUpdate, $update );
  56         }
  57
  58         function getGoodLinkID( $title ) {
  59                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  60                         return $this->mGoodLinks[$title];
  61                 } else {
  62                         return 0;
  63                 }
  64         }
  65
  66         function isBadLink( $title ) {
  67                 return array_key_exists( $title, $this->mBadLinks );
  68         }
  69
  70         function addGoodLinkObj( $id, $title ) {
  71                 if ( $this->mActive ) {
  72                         $dbkey = $title->getPrefixedDbKey();
  73                         $this->mGoodLinks[$dbkey] = $id;
  74                         $this->mPageLinks[$dbkey] = $title;
  75                 }
  76         }
  77
  78         function addBadLinkObj( $title ) {
  79                 $dbkey = $title->getPrefixedDbKey();
  80                 if ( $this->mActive && ( ! $this->isBadLink( $dbkey ) ) ) {
  81                         $this->mBadLinks[$dbkey] = 1;
  82                         $this->mPageLinks[$dbkey] = $title;
  83                 }
  84         }
  85
  86         function addImageLink( $title ) {
  87                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  88         }
  89
  90         function addImageLinkObj( $nt ) {
  91                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  92         }
  93
  94         function addCategoryLink( $title, $sortkey ) {
  95                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  96         }
  97
  98         function addCategoryLinkObj( &$nt, $sortkey ) {
  99                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
 100         }
 101
 102         function clearBadLink( $title ) {
 103                 unset( $this->mBadLinks[$title] );
 104                 $this->clearLink( $title );
 105         }
 106
 107         function clearLink( $title ) {
 108                 global $wgMemc, $wgLinkCacheMemcached;
 109                 if( $wgLinkCacheMemcached )
 110                         $wgMemc->delete( $this->getKey( $title ) );
 111         }
 112
 113         function suspend() { $this->mActive = false; }
 114         function resume() { $this->mActive = true; }
 115         function getPageLinks() { return $this->mPageLinks; }
 116         function getGoodLinks() { return $this->mGoodLinks; }
 117         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 118         function getImageLinks() { return $this->mImageLinks; }
 119         function getCategoryLinks() { return $this->mCategoryLinks; }
 120
 121         function addLink( $title ) {
 122                 $nt = Title::newFromDBkey( $title );
 123                 if( $nt ) {
 124                         return $this->addLinkObj( $nt );
 125                 } else {
 126                         return 0;
 127                 }
 128         }
 129
 130         function addLinkObj( &$nt ) {
 131                 global $wgMemc, $wgLinkCacheMemcached, $wgAntiLockFlags;
 132                 $title = $nt->getPrefixedDBkey();
 133                 if ( $this->isBadLink( $title ) ) { return 0; }
 134                 $id = $this->getGoodLinkID( $title );
 135                 if ( 0 != $id ) { return $id; }
 136
 137                 $fname = 'LinkCache::addLinkObj';
 138                 wfProfileIn( $fname );
 139
 140                 $ns = $nt->getNamespace();
 141                 $t = $nt->getDBkey();
 142
 143                 if ( '' == $title ) {
 144                         wfProfileOut( $fname );
 145                         return 0;
 146                 }
 147
 148                 $id = NULL;
 149                 if( $wgLinkCacheMemcached )
 150                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 151                 if( ! is_integer( $id ) ) {
 152                         if ( $this->mForUpdate ) {
 153                                 $db =& wfGetDB( DB_MASTER );
 154                                 if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
 155                                         $options = array( 'FOR UPDATE' );
 156                                 }
 157                         } else {
 158                                 $db =& wfGetDB( DB_SLAVE );
 159                                 $options = array();
 160                         }
 161
 162                         $id = $db->selectField( 'page', 'page_id', array( 'page_namespace' => $ns, 'page_title' => $t ), $fname, $options );
 163                         if ( !$id ) {
 164                                 $id = 0;
 165                         }
 166                         if( $wgLinkCacheMemcached )
 167                                 $wgMemc->add( $key, $id, 3600*24 );
 168                 }
 169
 170                 if( 0 == $id ) {
 171                         $this->addBadLinkObj( $nt );
 172                 } else {
 173                         $this->addGoodLinkObj( $id, $nt );
 174                 }
 175                 wfProfileOut( $fname );
 176                 return $id;
 177         }
 178
 179         /**
 180          * Bulk-check the pagelinks and page arrays for existence info.
 181          * @param Title $fromtitle
 182          */
 183         function preFill( &$fromtitle ) {
 184                 $fname = 'LinkCache::preFill';
 185                 wfProfileIn( $fname );
 186
 187                 $this->suspend();
 188                 $id = $fromtitle->getArticleID();
 189                 $this->resume();
 190
 191                 if( $id == 0 ) {
 192                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 193                         wfProfileOut( $fname );
 194                         return;
 195                 }
 196
 197                 if ( $this->mForUpdate ) {
 198                         $db =& wfGetDB( DB_MASTER );
 199                         $options = 'FOR UPDATE';
 200                 } else {
 201                         $db =& wfGetDB( DB_SLAVE );
 202                         $options = '';
 203                 }
 204
 205                 $page = $db->tableName( 'page' );
 206                 $pagelinks = $db->tableName( 'pagelinks' );
 207
 208                 $sql = "SELECT page_id,pl_namespace,pl_title
 209                         FROM $pagelinks
 210                         LEFT JOIN $page
 211                         ON pl_namespace=page_namespace AND pl_title=page_title
 212                         WHERE pl_from=$id $options";
 213                 $res = $db->query( $sql, $fname );
 214                 while( $s = $db->fetchObject( $res ) ) {
 215                         $title = Title::makeTitle( $s->pl_namespace, $s->pl_title );
 216                         if( $s->page_id ) {
 217                                 $this->addGoodLinkObj( $s->page_id, $title );
 218                         } else {
 219                                 $this->addBadLinkObj( $title );
 220                         }
 221                 }
 222                 $this->mPreFilled = true;
 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         function getPageAdditions() {
 254                 $set = array_diff( array_keys( $this->mPageLinks ), array_keys( $this->mOldPageLinks ) );
 255                 $out = array();
 256                 foreach( $set as $key ) {
 257                         $out[$key] = $this->mPageLinks[$key];
 258                 }
 259                 return $out;
 260         }
 261
 262         function getPageDeletions() {
 263                 $set = array_diff( array_keys( $this->mOldPageLinks ), array_keys( $this->mPageLinks ) );
 264                 $out = array();
 265                 foreach( $set as $key ) {
 266                         $out[$key] = $this->mOldPageLinks[$key];
 267                 }
 268                 return $out;
 269         }
 270
 271         /**
 272          * Parameters:
 273          * @param $which is one of the LINKCACHE_xxx constants
 274          * @param $del,$add are the incremental update arrays which will be filled.
 275          *
 276          * @return Returns whether or not it's worth doing the incremental version.
 277          *
 278          * For example, if [[List of mathematical topics]] was blanked,
 279          * it would take a long, long time to do incrementally.
 280          */
 281         function incrementalSetup( $which, &$del, &$add ) {
 282                 if ( ! $this->mPreFilled ) {
 283                         return false;
 284                 }
 285
 286                 switch ( $which ) {
 287                         case LINKCACHE_GOOD:
 288                                 $old =& $this->mOldGoodLinks;
 289                                 $cur =& $this->mGoodLinks;
 290                                 $del = $this->getGoodDeletions();
 291                                 $add = $this->getGoodAdditions();
 292                                 break;
 293                         case LINKCACHE_BAD:
 294                                 $old =& $this->mOldBadLinks;
 295                                 $cur =& $this->mBadLinks;
 296                                 $del = $this->getBadDeletions();
 297                                 $add = $this->getBadAdditions();
 298                                 break;
 299                         case LINKCACHE_PAGE:
 300                                 $old =& $this->mOldPageLinks;
 301                                 $cur =& $this->mPageLinks;
 302                                 $del = $this->getPageDeletions();
 303                                 $add = $this->getPageAdditions();
 304                                 break;
 305                         default: # LINKCACHE_IMAGE
 306                                 return false;
 307                 }
 308
 309                 return true;
 310         }
 311
 312         /**
 313          * Clears cache
 314          */
 315         function clear() {
 316                 $this->mPageLinks = array();
 317                 $this->mGoodLinks = array();
 318                 $this->mBadLinks = array();
 319                 $this->mImageLinks = array();
 320                 $this->mCategoryLinks = array();
 321                 $this->mOldGoodLinks = array();
 322                 $this->mOldBadLinks = array();
 323                 $this->mOldPageLinks = array();
 324         }
 325
 326         /**
 327          * Swaps old and current link registers
 328          */
 329         function swapRegisters() {
 330                 swap( $this->mGoodLinks, $this->mOldGoodLinks );
 331                 swap( $this->mBadLinks, $this->mOldBadLinks );
 332                 swap( $this->mImageLinks, $this->mOldImageLinks );
 333                 swap( $this->mPageLinks, $this->mOldPageLinks );
 334         }
 335 }
 336
 337 /**
 338  * Class representing a list of titles
 339  * The execute() method checks them all for existence and adds them to a LinkCache object
 340  +
 341  * @package MediaWiki
 342  * @subpackage Cache
 343  */
 344 class LinkBatch {
 345         /**
 346          * 2-d array, first index namespace, second index dbkey, value arbitrary
 347          */
 348         var $data = array();
 349
 350         function LinkBatch( $arr = array() ) {
 351                 foreach( $arr as $item ) {
 352                         $this->addObj( $item );
 353                 }
 354         }
 355
 356         function addObj( $title ) {
 357                 $this->add( $title->getNamespace(), $title->getDBkey() );
 358         }
 359
 360         function add( $ns, $dbkey ) {
 361                 if ( $ns < 0 ) {
 362                         return;
 363                 }
 364                 if ( !array_key_exists( $ns, $this->data ) ) {
 365                         $this->data[$ns] = array();
 366                 }
 367
 368                 $this->data[$ns][$dbkey] = 1;
 369         }
 370
 371         function execute( &$cache ) {
 372                 $fname = 'LinkBatch::execute';
 373                 $namespaces = array();
 374
 375                 if ( !count( $this->data ) ) {
 376                         return;
 377                 }
 378
 379                 wfProfileIn( $fname );
 380
 381                 // Construct query
 382                 // This is very similar to Parser::replaceLinkHolders
 383                 $dbr = wfGetDB( DB_SLAVE );
 384                 $page = $dbr->tableName( 'page' );
 385                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE "
 386                         . $this->constructSet( 'page', $dbr );
 387
 388                 // Do query
 389                 $res = $dbr->query( $sql, $fname );
 390
 391                 // Process results
 392                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 393
 394                 $remaining = $this->data;
 395                 while ( $row = $dbr->fetchObject( $res ) ) {
 396                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 397                         $cache->addGoodLinkObj( $row->page_id, $title );
 398                         unset( $remaining[$row->page_namespace][$row->page_title] );
 399                 }
 400                 $dbr->freeResult( $res );
 401
 402                 // The remaining links in $data are bad links, register them as such
 403                 foreach ( $remaining as $ns => $dbkeys ) {
 404                         foreach ( $dbkeys as $dbkey => $nothing ) {
 405                                 $title = Title::makeTitle( $ns, $dbkey );
 406                                 $cache->addBadLinkObj( $title );
 407                         }
 408                 }
 409
 410                 wfProfileOut( $fname );
 411         }
 412
 413         /**
 414          * Construct a WHERE clause which will match all the given titles.
 415          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 416          *
 417          * @param string $prefix
 418          * @return string
 419          * @access public
 420          */
 421         function constructSet( $prefix, $db ) {
 422                 $first = true;
 423                 $sql = '';
 424                 foreach ( $this->data as $ns => $dbkeys ) {
 425                         if ( !count( $dbkeys ) ) {
 426                                 continue;
 427                         }
 428
 429                         if ( $first ) {
 430                                 $first = false;
 431                         } else {
 432                                 $sql .= ' OR ';
 433                         }
 434                         $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 435
 436                         $firstTitle = true;
 437                         foreach( $dbkeys as $dbkey => $nothing ) {
 438                                 if ( $firstTitle ) {
 439                                         $firstTitle = false;
 440                                 } else {
 441                                         $sql .= ',';
 442                                 }
 443                                 $sql .= $db->addQuotes( $dbkey );
 444                         }
 445
 446                         $sql .= '))';
 447                 }
 448                 return $sql;
 449         }
 450 }
 451
 452 ?>