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                 global $wgAntiLockFlags;
 185                 $fname = 'LinkCache::preFill';
 186                 wfProfileIn( $fname );
 187
 188                 $this->suspend();
 189                 $id = $fromtitle->getArticleID();
 190                 $this->resume();
 191
 192                 if( $id == 0 ) {
 193                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 194                         wfProfileOut( $fname );
 195                         return;
 196                 }
 197
 198                 if ( $this->mForUpdate ) {
 199                         $db =& wfGetDB( DB_MASTER );
 200                         if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
 201                                 $options = 'FOR UPDATE';
 202                         } else {
 203                                 $options = '';
 204                         }
 205                 } else {
 206                         $db =& wfGetDB( DB_SLAVE );
 207                         $options = '';
 208                 }
 209
 210                 $page = $db->tableName( 'page' );
 211                 $pagelinks = $db->tableName( 'pagelinks' );
 212
 213                 $sql = "SELECT page_id,pl_namespace,pl_title
 214                         FROM $pagelinks
 215                         LEFT JOIN $page
 216                         ON pl_namespace=page_namespace AND pl_title=page_title
 217                         WHERE pl_from=$id $options";
 218                 $res = $db->query( $sql, $fname );
 219                 while( $s = $db->fetchObject( $res ) ) {
 220                         $title = Title::makeTitle( $s->pl_namespace, $s->pl_title );
 221                         if( $s->page_id ) {
 222                                 $this->addGoodLinkObj( $s->page_id, $title );
 223                         } else {
 224                                 $this->addBadLinkObj( $title );
 225                         }
 226                 }
 227                 $this->mPreFilled = true;
 228
 229                 wfProfileOut( $fname );
 230         }
 231
 232         function getGoodAdditions() {
 233                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 234         }
 235
 236         function getBadAdditions() {
 237                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 238                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 239                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 240         }
 241
 242         function getImageAdditions() {
 243                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 244         }
 245
 246         function getGoodDeletions() {
 247                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 248         }
 249
 250         function getBadDeletions() {
 251                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 252         }
 253
 254         function getImageDeletions() {
 255                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 256         }
 257
 258         function getPageAdditions() {
 259                 $set = array_diff( array_keys( $this->mPageLinks ), array_keys( $this->mOldPageLinks ) );
 260                 $out = array();
 261                 foreach( $set as $key ) {
 262                         $out[$key] = $this->mPageLinks[$key];
 263                 }
 264                 return $out;
 265         }
 266
 267         function getPageDeletions() {
 268                 $set = array_diff( array_keys( $this->mOldPageLinks ), array_keys( $this->mPageLinks ) );
 269                 $out = array();
 270                 foreach( $set as $key ) {
 271                         $out[$key] = $this->mOldPageLinks[$key];
 272                 }
 273                 return $out;
 274         }
 275
 276         /**
 277          * Parameters:
 278          * @param $which is one of the LINKCACHE_xxx constants
 279          * @param $del,$add are the incremental update arrays which will be filled.
 280          *
 281          * @return Returns whether or not it's worth doing the incremental version.
 282          *
 283          * For example, if [[List of mathematical topics]] was blanked,
 284          * it would take a long, long time to do incrementally.
 285          */
 286         function incrementalSetup( $which, &$del, &$add ) {
 287                 if ( ! $this->mPreFilled ) {
 288                         return false;
 289                 }
 290
 291                 switch ( $which ) {
 292                         case LINKCACHE_GOOD:
 293                                 $old =& $this->mOldGoodLinks;
 294                                 $cur =& $this->mGoodLinks;
 295                                 $del = $this->getGoodDeletions();
 296                                 $add = $this->getGoodAdditions();
 297                                 break;
 298                         case LINKCACHE_BAD:
 299                                 $old =& $this->mOldBadLinks;
 300                                 $cur =& $this->mBadLinks;
 301                                 $del = $this->getBadDeletions();
 302                                 $add = $this->getBadAdditions();
 303                                 break;
 304                         case LINKCACHE_PAGE:
 305                                 $old =& $this->mOldPageLinks;
 306                                 $cur =& $this->mPageLinks;
 307                                 $del = $this->getPageDeletions();
 308                                 $add = $this->getPageAdditions();
 309                                 break;
 310                         default: # LINKCACHE_IMAGE
 311                                 return false;
 312                 }
 313
 314                 return true;
 315         }
 316
 317         /**
 318          * Clears cache
 319          */
 320         function clear() {
 321                 $this->mPageLinks = array();
 322                 $this->mGoodLinks = array();
 323                 $this->mBadLinks = array();
 324                 $this->mImageLinks = array();
 325                 $this->mCategoryLinks = array();
 326                 $this->mOldGoodLinks = array();
 327                 $this->mOldBadLinks = array();
 328                 $this->mOldPageLinks = array();
 329         }
 330
 331         /**
 332          * Swaps old and current link registers
 333          */
 334         function swapRegisters() {
 335                 swap( $this->mGoodLinks, $this->mOldGoodLinks );
 336                 swap( $this->mBadLinks, $this->mOldBadLinks );
 337                 swap( $this->mImageLinks, $this->mOldImageLinks );
 338                 swap( $this->mPageLinks, $this->mOldPageLinks );
 339         }
 340 }
 341
 342 /**
 343  * Class representing a list of titles
 344  * The execute() method checks them all for existence and adds them to a LinkCache object
 345  +
 346  * @package MediaWiki
 347  * @subpackage Cache
 348  */
 349 class LinkBatch {
 350         /**
 351          * 2-d array, first index namespace, second index dbkey, value arbitrary
 352          */
 353         var $data = array();
 354
 355         function LinkBatch( $arr = array() ) {
 356                 foreach( $arr as $item ) {
 357                         $this->addObj( $item );
 358                 }
 359         }
 360
 361         function addObj( $title ) {
 362                 $this->add( $title->getNamespace(), $title->getDBkey() );
 363         }
 364
 365         function add( $ns, $dbkey ) {
 366                 if ( $ns < 0 ) {
 367                         return;
 368                 }
 369                 if ( !array_key_exists( $ns, $this->data ) ) {
 370                         $this->data[$ns] = array();
 371                 }
 372
 373                 $this->data[$ns][$dbkey] = 1;
 374         }
 375
 376         function execute( &$cache ) {
 377                 $fname = 'LinkBatch::execute';
 378                 $namespaces = array();
 379
 380                 if ( !count( $this->data ) ) {
 381                         return;
 382                 }
 383
 384                 wfProfileIn( $fname );
 385
 386                 // Construct query
 387                 // This is very similar to Parser::replaceLinkHolders
 388                 $dbr = wfGetDB( DB_SLAVE );
 389                 $page = $dbr->tableName( 'page' );
 390                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE "
 391                         . $this->constructSet( 'page', $dbr );
 392
 393                 // Do query
 394                 $res = $dbr->query( $sql, $fname );
 395
 396                 // Process results
 397                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 398
 399                 $remaining = $this->data;
 400                 while ( $row = $dbr->fetchObject( $res ) ) {
 401                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 402                         $cache->addGoodLinkObj( $row->page_id, $title );
 403                         unset( $remaining[$row->page_namespace][$row->page_title] );
 404                 }
 405                 $dbr->freeResult( $res );
 406
 407                 // The remaining links in $data are bad links, register them as such
 408                 foreach ( $remaining as $ns => $dbkeys ) {
 409                         foreach ( $dbkeys as $dbkey => $nothing ) {
 410                                 $title = Title::makeTitle( $ns, $dbkey );
 411                                 $cache->addBadLinkObj( $title );
 412                         }
 413                 }
 414
 415                 wfProfileOut( $fname );
 416         }
 417
 418         /**
 419          * Construct a WHERE clause which will match all the given titles.
 420          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 421          *
 422          * @param string $prefix
 423          * @return string
 424          * @access public
 425          */
 426         function constructSet( $prefix, $db ) {
 427                 $first = true;
 428                 $sql = '';
 429                 foreach ( $this->data as $ns => $dbkeys ) {
 430                         if ( !count( $dbkeys ) ) {
 431                                 continue;
 432                         }
 433
 434                         if ( $first ) {
 435                                 $first = false;
 436                         } else {
 437                                 $sql .= ' OR ';
 438                         }
 439                         $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 440
 441                         $firstTitle = true;
 442                         foreach( $dbkeys as $dbkey => $nothing ) {
 443                                 if ( $firstTitle ) {
 444                                         $firstTitle = false;
 445                                 } else {
 446                                         $sql .= ',';
 447                                 }
 448                                 $sql .= $db->addQuotes( $dbkey );
 449                         }
 450
 451                         $sql .= '))';
 452                 }
 453                 return $sql;
 454         }
 455 }
 456
 457 ?>