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         }
  49
  50         /**
  51          * General accessor to get/set whether SELECT FOR UPDATE should be used
  52          */
  53         function forUpdate( $update = NULL ) {
  54                 return wfSetVar( $this->mForUpdate, $update );
  55         }
  56
  57         function getGoodLinkID( $title ) {
  58                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  59                         return $this->mGoodLinks[$title];
  60                 } else {
  61                         return 0;
  62                 }
  63         }
  64
  65         function isBadLink( $title ) {
  66                 return array_key_exists( $title, $this->mBadLinks );
  67         }
  68
  69         function addGoodLinkObj( $id, $title ) {
  70                 if ( $this->mActive ) {
  71                         $dbkey = $title->getPrefixedDbKey();
  72                         $this->mGoodLinks[$dbkey] = $id;
  73                         $this->mPageLinks[$dbkey] = $title;
  74                 }
  75         }
  76
  77         function addBadLinkObj( $title ) {
  78                 $dbkey = $title->getPrefixedDbKey();
  79                 if ( $this->mActive && ( ! $this->isBadLink( $dbkey ) ) ) {
  80                         $this->mBadLinks[$dbkey] = 1;
  81                         $this->mPageLinks[$dbkey] = $title;
  82                 }
  83         }
  84
  85         function addImageLink( $title ) {
  86                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  87         }
  88
  89         function addImageLinkObj( $nt ) {
  90                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  91         }
  92
  93         function addCategoryLink( $title, $sortkey ) {
  94                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  95         }
  96
  97         function addCategoryLinkObj( &$nt, $sortkey ) {
  98                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
  99         }
 100
 101         function clearBadLink( $title ) {
 102                 unset( $this->mBadLinks[$title] );
 103                 $this->clearLink( $title );
 104         }
 105
 106         function clearLink( $title ) {
 107                 global $wgMemc, $wgLinkCacheMemcached;
 108                 if( $wgLinkCacheMemcached )
 109                         $wgMemc->delete( $this->getKey( $title ) );
 110         }
 111
 112         function suspend() { $this->mActive = false; }
 113         function resume() { $this->mActive = true; }
 114         function getPageLinks() { return $this->mPageLinks; }
 115         function getGoodLinks() { return $this->mGoodLinks; }
 116         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 117         function getImageLinks() { return $this->mImageLinks; }
 118         function getCategoryLinks() { return $this->mCategoryLinks; }
 119
 120         function addLink( $title ) {
 121                 $nt = Title::newFromDBkey( $title );
 122                 if( $nt ) {
 123                         return $this->addLinkObj( $nt );
 124                 } else {
 125                         return 0;
 126                 }
 127         }
 128
 129         function addLinkObj( &$nt ) {
 130                 global $wgMemc, $wgLinkCacheMemcached;
 131                 $title = $nt->getPrefixedDBkey();
 132                 if ( $this->isBadLink( $title ) ) { return 0; }
 133                 $id = $this->getGoodLinkID( $title );
 134                 if ( 0 != $id ) { return $id; }
 135
 136                 $fname = 'LinkCache::addLinkObj';
 137                 wfProfileIn( $fname );
 138
 139                 $ns = $nt->getNamespace();
 140                 $t = $nt->getDBkey();
 141
 142                 if ( '' == $title ) {
 143                         wfProfileOut( $fname );
 144                         return 0;
 145                 }
 146
 147                 $id = NULL;
 148                 if( $wgLinkCacheMemcached )
 149                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 150                 if( ! is_integer( $id ) ) {
 151                         if ( $this->mForUpdate ) {
 152                                 $db =& wfGetDB( DB_MASTER );
 153                                 $options = array( 'FOR UPDATE' );
 154                         } else {
 155                                 $db =& wfGetDB( DB_SLAVE );
 156                                 $options = array();
 157                         }
 158
 159                         $id = $db->selectField( 'page', 'page_id', array( 'page_namespace' => $ns, 'page_title' => $t ), $fname, $options );
 160                         if ( !$id ) {
 161                                 $id = 0;
 162                         }
 163                         if( $wgLinkCacheMemcached )
 164                                 $wgMemc->add( $key, $id, 3600*24 );
 165                 }
 166
 167                 if( 0 == $id ) {
 168                         $this->addBadLinkObj( $nt );
 169                 } else {
 170                         $this->addGoodLinkObj( $id, $nt );
 171                 }
 172                 wfProfileOut( $fname );
 173                 return $id;
 174         }
 175
 176         /**
 177          * Bulk-check the pagelinks and page arrays for existence info.
 178          * @param Title $fromtitle
 179          */
 180         function preFill( &$fromtitle ) {
 181                 global $wgEnablePersistentLC;
 182
 183                 $fname = 'LinkCache::preFill';
 184                 wfProfileIn( $fname );
 185
 186                 $this->suspend();
 187                 $id = $fromtitle->getArticleID();
 188                 $this->resume();
 189
 190                 if( $id == 0 ) {
 191                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 192                         wfProfileOut( $fname );
 193                         return;
 194                 }
 195
 196                 if ( $wgEnablePersistentLC ) {
 197                         if( $this->fillFromLinkscc( $id ) ){
 198                                 wfProfileOut( $fname );
 199                                 return;
 200                         }
 201                 }
 202                 if ( $this->mForUpdate ) {
 203                         $db =& wfGetDB( DB_MASTER );
 204                         $options = 'FOR UPDATE';
 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->mOldPageLinks = $this->mPageLinks;
 228                 $this->mOldBadLinks  = $this->mBadLinks;
 229                 $this->mOldGoodLinks = $this->mGoodLinks;
 230                 $this->mPreFilled = true;
 231
 232                 if ( $wgEnablePersistentLC ) {
 233                         $this->saveToLinkscc( $id );
 234                 }
 235                 wfProfileOut( $fname );
 236         }
 237
 238         function getGoodAdditions() {
 239                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 240         }
 241
 242         function getBadAdditions() {
 243                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 244                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 245                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 246         }
 247
 248         function getImageAdditions() {
 249                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 250         }
 251
 252         function getGoodDeletions() {
 253                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 254         }
 255
 256         function getBadDeletions() {
 257                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 258         }
 259
 260         function getImageDeletions() {
 261                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 262         }
 263
 264         function getPageAdditions() {
 265                 $set = array_diff( array_keys( $this->mPageLinks ), array_keys( $this->mOldPageLinks ) );
 266                 $out = array();
 267                 foreach( $set as $key ) {
 268                         $out[$key] = $this->mPageLinks[$key];
 269                 }
 270                 return $out;
 271         }
 272
 273         function getPageDeletions() {
 274                 $set = array_diff( array_keys( $this->mOldPageLinks ), array_keys( $this->mPageLinks ) );
 275                 $out = array();
 276                 foreach( $set as $key ) {
 277                         $out[$key] = $this->mOldPageLinks[$key];
 278                 }
 279                 return $out;
 280         }
 281
 282         /**
 283          * Parameters:
 284          * @param $which is one of the LINKCACHE_xxx constants
 285          * @param $del,$add are the incremental update arrays which will be filled.
 286          *
 287          * @return Returns whether or not it's worth doing the incremental version.
 288          *
 289          * For example, if [[List of mathematical topics]] was blanked,
 290          * it would take a long, long time to do incrementally.
 291          */
 292         function incrementalSetup( $which, &$del, &$add ) {
 293                 if ( ! $this->mPreFilled ) {
 294                         return false;
 295                 }
 296
 297                 switch ( $which ) {
 298                         case LINKCACHE_GOOD:
 299                                 $old =& $this->mOldGoodLinks;
 300                                 $cur =& $this->mGoodLinks;
 301                                 $del = $this->getGoodDeletions();
 302                                 $add = $this->getGoodAdditions();
 303                                 break;
 304                         case LINKCACHE_BAD:
 305                                 $old =& $this->mOldBadLinks;
 306                                 $cur =& $this->mBadLinks;
 307                                 $del = $this->getBadDeletions();
 308                                 $add = $this->getBadAdditions();
 309                                 break;
 310                         case LINKCACHE_PAGE:
 311                                 $old =& $this->mOldPageLinks;
 312                                 $cur =& $this->mPageLinks;
 313                                 $del = $this->getPageDeletions();
 314                                 $add = $this->getPageAdditions();
 315                                 break;
 316                         default: # LINKCACHE_IMAGE
 317                                 return false;
 318                 }
 319
 320                 return true;
 321         }
 322
 323         /**
 324          * Clears cache but leaves old preFill copies alone
 325          */
 326         function clear() {
 327                 $this->mPageLinks = array();
 328                 $this->mGoodLinks = array();
 329                 $this->mBadLinks = array();
 330                 $this->mImageLinks = array();
 331         }
 332
 333         /**
 334          * @access private
 335          */
 336         function fillFromLinkscc( $id ){
 337                 $fname = 'LinkCache::fillFromLinkscc';
 338
 339                 $id = IntVal( $id );
 340                 if ( $this->mForUpdate ) {
 341                         $db =& wfGetDB( DB_MASTER );
 342                         $options = 'FOR UPDATE';
 343                 } else {
 344                         $db =& wfGetDB( DB_SLAVE );
 345                         $options = '';
 346                 }
 347                 $raw = $db->selectField( 'linkscc', 'lcc_cacheobj', array( 'lcc_pageid' => $id ), $fname, $options );
 348                 if ( $raw === false ) {
 349                         return false;
 350                 }
 351
 352                 $cacheobj = false;
 353                 if( function_exists( 'gzuncompress' ) )
 354                         $cacheobj = @gzuncompress( $raw );
 355
 356                 if($cacheobj == FALSE){
 357                         $cacheobj = $raw;
 358                 }
 359                 $cc = @unserialize( $cacheobj );
 360                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 361                         $this->mOldPageLinks = $this->mPageLinks = $cc->mPageLinks;
 362                         $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 363                         $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 364                         $this->mPreFilled = true;
 365                         return TRUE;
 366                 } else {
 367                         return FALSE;
 368                 }
 369
 370         }
 371
 372         /**
 373          * @access private
 374          */
 375         function saveToLinkscc( $pid ){
 376                 global $wgCompressedPersistentLC;
 377                 if( $wgCompressedPersistentLC and function_exists( 'gzcompress' ) ) {
 378                         $ser = gzcompress( serialize( $this ), 3 );
 379                 } else {
 380                         $ser = serialize( $this );
 381                 }
 382                 $db =& wfGetDB( DB_MASTER );
 383                 $db->replace( 'linkscc', array( 'lcc_pageid' ), array( 'lcc_pageid' => $pid, 'lcc_cacheobj' => $ser ) );
 384         }
 385
 386         /**
 387          * Delete linkscc rows which link to here
 388          * @param $title The page linked to
 389          * @static
 390          */
 391         function linksccClearLinksTo( $title ){
 392                 global $wgEnablePersistentLC;
 393                 if ( $wgEnablePersistentLC ) {
 394                         $fname = 'LinkCache::linksccClearLinksTo';
 395                         $pid = intval( $pid );
 396                         $dbw =& wfGetDB( DB_MASTER );
 397                         # Delete linkscc rows which link to here
 398                         $dbw->deleteJoin( 'linkscc', 'pagelinks', 'lcc_pageid', 'pl_from',
 399                                 array(
 400                                         'pl_namespace' => $title->getNamespace(),
 401                                         'pl-title'     => $title->getDbKey() ),
 402                                 $fname );
 403                         # Delete linkscc row representing this page
 404                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ), $fname);
 405                 }
 406
 407         }
 408
 409         /**
 410          * @param $pid is a page id
 411          * @static
 412          */
 413         function linksccClearPage( $pid ){
 414                 global $wgEnablePersistentLC;
 415                 if ( $wgEnablePersistentLC ) {
 416                         $pid = intval( $pid );
 417                         $dbw =& wfGetDB( DB_MASTER );
 418                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ) );
 419                 }
 420         }
 421 }
 422
 423 /**
 424  * Class representing a list of titles
 425  * The execute() method checks them all for existence and adds them to a LinkCache object
 426  +
 427  * @package MediaWikki
 428  * @subpackage Cache
 429  */
 430 class LinkBatch {
 431         /**
 432          * 2-d array, first index namespace, second index dbkey, value arbitrary
 433          */
 434         var $data = array();
 435
 436         function LinkBatch( $arr = array() ) {
 437                 foreach( $arr as $item ) {
 438                         $this->addObj( $item );
 439                 }
 440         }
 441
 442         function addObj( $title ) {
 443                 $this->add( $title->getNamespace(), $title->getDBkey() );
 444         }
 445
 446         function add( $ns, $dbkey ) {
 447                 if ( $ns < 0 ) {
 448                         return;
 449                 }
 450                 if ( !array_key_exists( $ns, $this->data ) ) {
 451                         $this->data[$ns] = array();
 452                 }
 453
 454                 $this->data[$ns][$dbkey] = 1;
 455         }
 456
 457         function execute( &$cache ) {
 458                 $fname = 'LinkBatch::execute';
 459                 $namespaces = array();
 460
 461                 if ( !count( $this->data ) ) {
 462                         return;
 463                 }
 464
 465                 wfProfileIn( $fname );
 466
 467                 // Construct query
 468                 // This is very similar to Parser::replaceLinkHolders
 469                 $dbr = wfGetDB( DB_SLAVE );
 470                 $page = $dbr->tableName( 'page' );
 471                 $sql = "SELECT page_id, page_namespace, page_title FROM $page WHERE "
 472                         . $this->constructSet( 'page', $dbr );
 473
 474                 // Do query
 475                 $res = $dbr->query( $sql, $fname );
 476
 477                 // Process results
 478                 // For each returned entry, add it to the list of good links, and remove it from $remaining
 479
 480                 $remaining = $this->data;
 481                 while ( $row = $dbr->fetchObject( $res ) ) {
 482                         $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 483                         $cache->addGoodLinkObj( $row->page_id, $title );
 484                         unset( $remaining[$row->page_namespace][$row->page_title] );
 485                 }
 486                 $dbr->freeResult( $res );
 487
 488                 // The remaining links in $data are bad links, register them as such
 489                 foreach ( $remaining as $ns => $dbkeys ) {
 490                         foreach ( $dbkeys as $dbkey => $nothing ) {
 491                                 $title = Title::makeTitle( $ns, $dbkey );
 492                                 $cache->addBadLinkObj( $title );
 493                         }
 494                 }
 495
 496                 wfProfileOut( $fname );
 497         }
 498
 499         /**
 500          * Construct a WHERE clause which will match all the given titles.
 501          * Give the appropriate table's field name prefix ('page', 'pl', etc).
 502          *
 503          * @param string $prefix
 504          * @return string
 505          * @access public
 506          */
 507         function constructSet( $prefix, $db ) {
 508                 $first = true;
 509                 $sql = '';
 510                 foreach ( $this->data as $ns => $dbkeys ) {
 511                         if ( !count( $dbkeys ) ) {
 512                                 continue;
 513                         }
 514
 515                         if ( $first ) {
 516                                 $first = false;
 517                         } else {
 518                                 $sql .= ' OR ';
 519                         }
 520                         $sql .= "({$prefix}_namespace=$ns AND {$prefix}_title IN (";
 521
 522                         $firstTitle = true;
 523                         foreach( $dbkeys as $dbkey => $nothing ) {
 524                                 if ( $firstTitle ) {
 525                                         $firstTitle = false;
 526                                 } else {
 527                                         $sql .= ',';
 528                                 }
 529                                 $sql .= $db->addQuotes( $dbkey );
 530                         }
 531
 532                         $sql .= '))';
 533                 }
 534                 return $sql;
 535         }
 536 }
 537
 538 ?>