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                                 } else {
 157                                         $options = array();
 158                                 }
 159                         } else {
 160                                 $db =& wfGetDB( DB_SLAVE );
 161                                 $options = array();
 162                         }
 163
 164                         $id = $db->selectField( 'page', 'page_id',
 165                                         array( 'page_namespace' => $ns, 'page_title' => $t ),
 166                                         $fname, $options );
 167 wfdebug("link cache: id=$id\n");
 168                         if ( !$id ) {
 169                                 $id = 0;
 170                         }
 171                         if( $wgLinkCacheMemcached )
 172                                 $wgMemc->add( $key, $id, 3600*24 );
 173                 }
 174
 175                 if( 0 == $id ) {
 176                         $this->addBadLinkObj( $nt );
 177                 } else {
 178                         $this->addGoodLinkObj( $id, $nt );
 179                 }
 180                 wfProfileOut( $fname );
 181                 return $id;
 182         }
 183
 184         /**
 185          * Bulk-check the pagelinks and page arrays for existence info.
 186          * @param Title $fromtitle
 187          */
 188         function preFill( &$fromtitle ) {
 189                 global $wgAntiLockFlags;
 190                 $fname = 'LinkCache::preFill';
 191                 wfProfileIn( $fname );
 192
 193                 $this->suspend();
 194                 $id = $fromtitle->getArticleID();
 195                 $this->resume();
 196
 197                 if( $id == 0 ) {
 198                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 199                         wfProfileOut( $fname );
 200                         return;
 201                 }
 202
 203                 if ( $this->mForUpdate ) {
 204                         $db =& wfGetDB( DB_MASTER );
 205                         if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
 206                                 $options = 'FOR UPDATE';
 207                         } else {
 208                                 $options = '';
 209                         }
 210                 } else {
 211                         $db =& wfGetDB( DB_SLAVE );
 212                         $options = '';
 213                 }
 214
 215                 $page = $db->tableName( 'page' );
 216                 $pagelinks = $db->tableName( 'pagelinks' );
 217
 218                 $sql = "SELECT page_id,pl_namespace,pl_title
 219                         FROM $pagelinks
 220                         LEFT JOIN $page
 221                         ON pl_namespace=page_namespace AND pl_title=page_title
 222                         WHERE pl_from=$id $options";
 223                 $res = $db->query( $sql, $fname );
 224                 while( $s = $db->fetchObject( $res ) ) {
 225                         $title = Title::makeTitle( $s->pl_namespace, $s->pl_title );
 226                         if( $s->page_id ) {
 227                                 $this->addGoodLinkObj( $s->page_id, $title );
 228                         } else {
 229                                 $this->addBadLinkObj( $title );
 230                         }
 231                 }
 232                 $this->mPreFilled = true;
 233
 234                 wfProfileOut( $fname );
 235         }
 236
 237         function getGoodAdditions() {
 238                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 239         }
 240
 241         function getBadAdditions() {
 242                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 243                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 244                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 245         }
 246
 247         function getImageAdditions() {
 248                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 249         }
 250
 251         function getGoodDeletions() {
 252                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 253         }
 254
 255         function getBadDeletions() {
 256                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 257         }
 258
 259         function getImageDeletions() {
 260                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 261         }
 262
 263         function getPageAdditions() {
 264                 $set = array_diff( array_keys( $this->mPageLinks ), array_keys( $this->mOldPageLinks ) );
 265                 $out = array();
 266                 foreach( $set as $key ) {
 267                         $out[$key] = $this->mPageLinks[$key];
 268                 }
 269                 return $out;
 270         }
 271
 272         function getPageDeletions() {
 273                 $set = array_diff( array_keys( $this->mOldPageLinks ), array_keys( $this->mPageLinks ) );
 274                 $out = array();
 275                 foreach( $set as $key ) {
 276                         $out[$key] = $this->mOldPageLinks[$key];
 277                 }
 278                 return $out;
 279         }
 280
 281         /**
 282          * Parameters:
 283          * @param $which is one of the LINKCACHE_xxx constants
 284          * @param $del,$add are the incremental update arrays which will be filled.
 285          *
 286          * @return Returns whether or not it's worth doing the incremental version.
 287          *
 288          * For example, if [[List of mathematical topics]] was blanked,
 289          * it would take a long, long time to do incrementally.
 290          */
 291         function incrementalSetup( $which, &$del, &$add ) {
 292                 if ( ! $this->mPreFilled ) {
 293                         return false;
 294                 }
 295
 296                 switch ( $which ) {
 297                         case LINKCACHE_GOOD:
 298                                 $old =& $this->mOldGoodLinks;
 299                                 $cur =& $this->mGoodLinks;
 300                                 $del = $this->getGoodDeletions();
 301                                 $add = $this->getGoodAdditions();
 302                                 break;
 303                         case LINKCACHE_BAD:
 304                                 $old =& $this->mOldBadLinks;
 305                                 $cur =& $this->mBadLinks;
 306                                 $del = $this->getBadDeletions();
 307                                 $add = $this->getBadAdditions();
 308                                 break;
 309                         case LINKCACHE_PAGE:
 310                                 $old =& $this->mOldPageLinks;
 311                                 $cur =& $this->mPageLinks;
 312                                 $del = $this->getPageDeletions();
 313                                 $add = $this->getPageAdditions();
 314                                 break;
 315                         default: # LINKCACHE_IMAGE
 316                                 return false;
 317                 }
 318
 319                 return true;
 320         }
 321
 322         /**
 323          * Clears cache
 324          */
 325         function clear() {
 326                 $this->mPageLinks = array();
 327                 $this->mGoodLinks = array();
 328                 $this->mBadLinks = array();
 329                 $this->mImageLinks = array();
 330                 $this->mCategoryLinks = array();
 331                 $this->mOldGoodLinks = array();
 332                 $this->mOldBadLinks = array();
 333                 $this->mOldPageLinks = array();
 334         }
 335
 336         /**
 337          * Swaps old and current link registers
 338          */
 339         function swapRegisters() {
 340                 swap( $this->mGoodLinks, $this->mOldGoodLinks );
 341                 swap( $this->mBadLinks, $this->mOldBadLinks );
 342                 swap( $this->mImageLinks, $this->mOldImageLinks );
 343                 swap( $this->mPageLinks, $this->mOldPageLinks );
 344         }
 345 }
 346
 347 /**
 348  * Class representing a list of titles
 349  * The execute() method checks them all for existence and adds them to a LinkCache object
 350  +
 351  * @package MediaWiki
 352  * @subpackage Cache
 353  */
 354 class LinkBatch {
 355         /**
 356          * 2-d array, first index namespace, second index dbkey, value arbitrary
 357          */
 358         var $data = array();
 359
 360         function LinkBatch( $arr = array() ) {
 361                 foreach( $arr as $item ) {
 362                         $this->addObj( $item );
 363                 }
 364         }
 365
 366         function addObj( $title ) {
 367                 $this->add( $title->getNamespace(), $title->getDBkey() );
 368         }
 369
 370         function add( $ns, $dbkey ) {
 371                 if ( $ns < 0 ) {
 372                         return;
 373                 }
 374                 if ( !array_key_exists( $ns, $this->data ) ) {
 375                         $this->data[$ns] = array();
 376                 }
 377
 378                 $this->data[$ns][$dbkey] = 1;
 379         }
 380
 381         function execute( &$cache ) {
 382                 $fname = 'LinkBatch::execute';
 383                 $namespaces = array();
 384
 385                 if ( !count( $this->data ) ) {
 386                         return;
 387                 }
 388
 389                 wfProfileIn( $fname );
 390
 391                 // Construct query
 392                 // This is very similar to Parser::replaceLinkHolders
 393                 $dbr =& wfGetDB( DB_SLAVE );
 394                 $page = $dbr->tableName( 'page' );
 395                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE "
 396                         . $this->constructSet( 'page', $dbr );
 397
 398                 // Do query
 399                 $res = $dbr->query( $sql, $fname );
 400
 401                 // Process results
 402                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 403
 404                 $remaining = $this->data;
 405                 while ( $row = $dbr->fetchObject( $res ) ) {
 406                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 407                         $cache->addGoodLinkObj( $row->page_id, $title );
 408                         unset( $remaining[$row->page_namespace][$row->page_title] );
 409                 }
 410                 $dbr->freeResult( $res );
 411
 412                 // The remaining links in $data are bad links, register them as such
 413                 foreach ( $remaining as $ns => $dbkeys ) {
 414                         foreach ( $dbkeys as $dbkey => $nothing ) {
 415                                 $title = Title::makeTitle( $ns, $dbkey );
 416                                 $cache->addBadLinkObj( $title );
 417                         }
 418                 }
 419
 420                 wfProfileOut( $fname );
 421         }
 422
 423         /**
 424          * Construct a WHERE clause which will match all the given titles.
 425          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 426          *
 427          * @param string $prefix
 428          * @return string
 429          * @access public
 430          */
 431         function constructSet( $prefix, $db ) {
 432                 $first = true;
 433                 $sql = '';
 434                 foreach ( $this->data as $ns => $dbkeys ) {
 435                         if ( !count( $dbkeys ) ) {
 436                                 continue;
 437                         }
 438
 439                         if ( $first ) {
 440                                 $first = false;
 441                         } else {
 442                                 $sql .= ' OR ';
 443                         }
 444                         $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 445
 446                         $firstTitle = true;
 447                         foreach( $dbkeys as $dbkey => $nothing ) {
 448                                 if ( $firstTitle ) {
 449                                         $firstTitle = false;
 450                                 } else {
 451                                         $sql .= ',';
 452                                 }
 453                                 $sql .= $db->addQuotes( $dbkey );
 454                         }
 455
 456                         $sql .= '))';
 457                 }
 458                 return $sql;
 459         }
 460 }
 461
 462 ?>