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         /** @deprecated */
 114         function suspend() { $this->mActive = false; }
 115         /** @deprecated */
 116         function resume() { $this->mActive = true; }
 117
 118         function getPageLinks() { return $this->mPageLinks; }
 119         function getGoodLinks() { return $this->mGoodLinks; }
 120         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 121         function getImageLinks() { return $this->mImageLinks; }
 122         function getCategoryLinks() { return $this->mCategoryLinks; }
 123
 124         /**
 125          * Add a title to the link cache, return the page_id or zero if non-existent
 126          * @param string $title Title to add
 127          * @return integer
 128          */
 129         function addLink( $title ) {
 130                 $nt = Title::newFromDBkey( $title );
 131                 if( $nt ) {
 132                         return $this->addLinkObj( $nt );
 133                 } else {
 134                         return 0;
 135                 }
 136         }
 137
 138         /**
 139          * Add a title to the link cache, return the page_id or zero if non-existent
 140          * @param Title $nt Title to add
 141          * @return integer
 142          */
 143         function addLinkObj( &$nt ) {
 144                 global $wgMemc, $wgLinkCacheMemcached, $wgAntiLockFlags;
 145                 $title = $nt->getPrefixedDBkey();
 146                 if ( $this->isBadLink( $title ) ) { return 0; }
 147                 $id = $this->getGoodLinkID( $title );
 148                 if ( 0 != $id ) { return $id; }
 149
 150                 $fname = 'LinkCache::addLinkObj';
 151                 global $wgProfiling, $wgProfiler;
 152                 if ( $wgProfiling && isset( $wgProfiler ) ) {
 153                         $fname .= ' (' . $wgProfiler->getCurrentSection() . ')';
 154                 }
 155
 156                 wfProfileIn( $fname );
 157
 158                 $ns = $nt->getNamespace();
 159                 $t = $nt->getDBkey();
 160
 161                 if ( '' == $title ) {
 162                         wfProfileOut( $fname );
 163                         return 0;
 164                 }
 165
 166                 $id = NULL;
 167                 if( $wgLinkCacheMemcached )
 168                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 169                 if( ! is_integer( $id ) ) {
 170                         if ( $this->mForUpdate ) {
 171                                 $db =& wfGetDB( DB_MASTER );
 172                                 if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
 173                                         $options = array( 'FOR UPDATE' );
 174                                 } else {
 175                                         $options = array();
 176                                 }
 177                         } else {
 178                                 $db =& wfGetDB( DB_SLAVE );
 179                                 $options = array();
 180                         }
 181
 182                         $id = $db->selectField( 'page', 'page_id',
 183                                         array( 'page_namespace' => $ns, 'page_title' => $t ),
 184                                         $fname, $options );
 185                         if ( !$id ) {
 186                                 $id = 0;
 187                         }
 188                         if( $wgLinkCacheMemcached )
 189                                 $wgMemc->add( $key, $id, 3600*24 );
 190                 }
 191
 192                 if( 0 == $id ) {
 193                         $this->addBadLinkObj( $nt );
 194                 } else {
 195                         $this->addGoodLinkObj( $id, $nt );
 196                 }
 197                 wfProfileOut( $fname );
 198                 return $id;
 199         }
 200
 201         /**
 202          * Bulk-check the pagelinks and page arrays for existence info.
 203          * @param Title $fromtitle
 204          * @deprecated
 205          */
 206         function preFill( &$fromtitle ) {
 207                 global $wgAntiLockFlags;
 208                 $fname = 'LinkCache::preFill';
 209                 wfProfileIn( $fname );
 210
 211                 $this->suspend();
 212                 $id = $fromtitle->getArticleID();
 213                 $this->resume();
 214
 215                 if( $id == 0 ) {
 216                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 217                         wfProfileOut( $fname );
 218                         return;
 219                 }
 220
 221                 if ( $this->mForUpdate ) {
 222                         $db =& wfGetDB( DB_MASTER );
 223                         if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
 224                                 $options = 'FOR UPDATE';
 225                         } else {
 226                                 $options = '';
 227                         }
 228                 } else {
 229                         $db =& wfGetDB( DB_SLAVE );
 230                         $options = '';
 231                 }
 232
 233                 $page = $db->tableName( 'page' );
 234                 $pagelinks = $db->tableName( 'pagelinks' );
 235
 236                 $sql = "SELECT page_id,pl_namespace,pl_title
 237                         FROM $pagelinks
 238                         LEFT JOIN $page
 239                         ON pl_namespace=page_namespace AND pl_title=page_title
 240                         WHERE pl_from=$id $options";
 241                 $res = $db->query( $sql, $fname );
 242                 while( $s = $db->fetchObject( $res ) ) {
 243                         $title = Title::makeTitle( $s->pl_namespace, $s->pl_title );
 244                         if( $s->page_id ) {
 245                                 $this->addGoodLinkObj( $s->page_id, $title );
 246                         } else {
 247                                 $this->addBadLinkObj( $title );
 248                         }
 249                 }
 250                 $this->mPreFilled = true;
 251
 252                 wfProfileOut( $fname );
 253         }
 254
 255         /**
 256          * Clears cache
 257          */
 258         function clear() {
 259                 $this->mPageLinks = array();
 260                 $this->mGoodLinks = array();
 261                 $this->mBadLinks = array();
 262                 $this->mImageLinks = array();
 263                 $this->mCategoryLinks = array();
 264                 $this->mOldGoodLinks = array();
 265                 $this->mOldBadLinks = array();
 266                 $this->mOldPageLinks = array();
 267         }
 268
 269         /**
 270          * Swaps old and current link registers
 271          * @deprecated
 272          */
 273         function swapRegisters() {
 274                 swap( $this->mGoodLinks, $this->mOldGoodLinks );
 275                 swap( $this->mBadLinks, $this->mOldBadLinks );
 276                 swap( $this->mImageLinks, $this->mOldImageLinks );
 277                 swap( $this->mPageLinks, $this->mOldPageLinks );
 278         }
 279 }
 280
 281 /**
 282  * Class representing a list of titles
 283  * The execute() method checks them all for existence and adds them to a LinkCache object
 284  +
 285  * @package MediaWiki
 286  * @subpackage Cache
 287  */
 288 class LinkBatch {
 289         /**
 290          * 2-d array, first index namespace, second index dbkey, value arbitrary
 291          */
 292         var $data = array();
 293
 294         function LinkBatch( $arr = array() ) {
 295                 foreach( $arr as $item ) {
 296                         $this->addObj( $item );
 297                 }
 298         }
 299
 300         function addObj( $title ) {
 301                 if ( is_object( $title ) ) {
 302                         $this->add( $title->getNamespace(), $title->getDBkey() );
 303                 } else {
 304                         wfDebug( "Warning: LinkBatch::addObj got invalid title object\n" );
 305                 }
 306         }
 307
 308         function add( $ns, $dbkey ) {
 309                 if ( $ns < 0 ) {
 310                         return;
 311                 }
 312                 if ( !array_key_exists( $ns, $this->data ) ) {
 313                         $this->data[$ns] = array();
 314                 }
 315
 316                 $this->data[$ns][$dbkey] = 1;
 317         }
 318
 319         /**
 320          * Set the link list to a given 2-d array
 321          * First key is the namespace, second is the DB key, value arbitrary
 322          */
 323         function setArray( $array ) {
 324                 $this->data = $array;
 325         }
 326
 327         /**
 328          * Do the query and add the results to a LinkCache object
 329          * Return an array mapping PDBK to ID
 330          */
 331         function execute( &$cache ) {
 332                 $fname = 'LinkBatch::execute';
 333                 wfProfileIn( $fname );
 334                 // Do query
 335                 $res = $this->doQuery();
 336                 if ( !$res ) {
 337                         wfProfileOut( $fname );
 338                         return array();
 339                 }
 340
 341                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 342
 343                 $ids = array();
 344                 $remaining = $this->data;
 345                 while ( $row = $res->fetchObject() ) {
 346                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 347                         $cache->addGoodLinkObj( $row->page_id, $title );
 348                         $ids[$title->getPrefixedDBkey()] = $row->page_id;
 349                         unset( $remaining[$row->page_namespace][$row->page_title] );
 350                 }
 351                 $res->free();
 352
 353                 // The remaining links in $data are bad links, register them as such
 354                 foreach ( $remaining as $ns => $dbkeys ) {
 355                         foreach ( $dbkeys as $dbkey => $nothing ) {
 356                                 $title = Title::makeTitle( $ns, $dbkey );
 357                                 $cache->addBadLinkObj( $title );
 358                                 $ids[$title->getPrefixedDBkey()] = 0;
 359                         }
 360                 }
 361                 wfProfileOut( $fname );
 362                 return $ids;
 363         }
 364
 365         /**
 366          * Perform the existence test query, return a ResultWrapper with page_id fields
 367          */
 368         function doQuery() {
 369                 $fname = 'LinkBatch::execute';
 370                 $namespaces = array();
 371
 372                 if ( !count( $this->data ) ) {
 373                         return false;
 374                 }
 375                 wfProfileIn( $fname );
 376
 377                 // Construct query
 378                 // This is very similar to Parser::replaceLinkHolders
 379                 $dbr =& wfGetDB( DB_SLAVE );
 380                 $page = $dbr->tableName( 'page' );
 381                 $set = $this->constructSet( 'page', $dbr );
 382                 if ( $set === false ) {
 383                         return false;
 384                 }
 385                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE $set";
 386
 387                 // Do query
 388                 $res = new ResultWrapper( $dbr,  $dbr->query( $sql, $fname ) );
 389                 wfProfileOut( $fname );
 390                 return $res;
 391         }
 392
 393         /**
 394          * Construct a WHERE clause which will match all the given titles.
 395          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 396          *
 397          * @param string $prefix
 398          * @return string
 399          * @access public
 400          */
 401         function constructSet( $prefix, &$db ) {
 402                 $first = true;
 403                 $firstTitle = true;
 404                 $sql = '';
 405                 foreach ( $this->data as $ns => $dbkeys ) {
 406                         if ( !count( $dbkeys ) ) {
 407                                 continue;
 408                         }
 409
 410                         if ( $first ) {
 411                                 $first = false;
 412                         } else {
 413                                 $sql .= ' OR ';
 414                         }
 415                         $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 416
 417                         $firstTitle = true;
 418                         foreach( $dbkeys as $dbkey => $nothing ) {
 419                                 if ( $firstTitle ) {
 420                                         $firstTitle = false;
 421                                 } else {
 422                                         $sql .= ',';
 423                                 }
 424                                 $sql .= $db->addQuotes( $dbkey );
 425                         }
 426
 427                         $sql .= '))';
 428                 }
 429                 if ( $first && $firstTitle ) {
 430                         # No titles added
 431                         return false;
 432                 } else {
 433                         return $sql;
 434                 }
 435         }
 436 }
 437
 438 ?>