includes/LinkCache.php

   1 <?php
   2 /**
   3  * Cache for article titles (prefixed DB keys) and ids linked from one source
   4  */
   5
   6 /**
   7  *
   8  */
   9 # These are used in incrementalSetup()
  10 define ('LINKCACHE_GOOD', 0);
  11 define ('LINKCACHE_BAD', 1);
  12 define ('LINKCACHE_IMAGE', 2);
  13
  14 /**
  15  *
  16  */
  17 class LinkCache {
  18         // Increment $mClassVer whenever old serialized versions of this class
  19         // becomes incompatible with the new version.
  20         /* private */ var $mClassVer = 2;
  21
  22         /* private */ var $mGoodLinks, $mBadLinks, $mActive;
  23         /* private */ var $mImageLinks, $mCategoryLinks;
  24         /* private */ var $mPreFilled, $mOldGoodLinks, $mOldBadLinks;
  25         /* private */ var $mForUpdate;
  26
  27         /* private */ function getKey( $title ) {
  28                 global $wgDBname;
  29                 return $wgDBname.':lc:title:'.$title;
  30         }
  31
  32         function LinkCache() {
  33                 $this->mActive = true;
  34                 $this->mPreFilled = false;
  35                 $this->mForUpdate = false;
  36                 $this->mGoodLinks = array();
  37                 $this->mBadLinks = array();
  38                 $this->mImageLinks = array();
  39                 $this->mCategoryLinks = array();
  40                 $this->mOldGoodLinks = array();
  41                 $this->mOldBadLinks = array();
  42         }
  43
  44         /**
  45          * General accessor to get/set whether SELECT FOR UPDATE should be used
  46          */
  47         function forUpdate( $update = NULL ) {
  48                 return wfSetVar( $this->mForUpdate, $update );
  49         }
  50
  51         function getGoodLinkID( $title ) {
  52                 if ( array_key_exists( $title, $this->mGoodLinks ) ) {
  53                         return $this->mGoodLinks[$title];
  54                 } else {
  55                         return 0;
  56                 }
  57         }
  58
  59         function isBadLink( $title ) {
  60                 return array_key_exists( $title, $this->mBadLinks );
  61         }
  62
  63         function addGoodLink( $id, $title ) {
  64                 if ( $this->mActive ) {
  65                         $this->mGoodLinks[$title] = $id;
  66                 }
  67         }
  68
  69         function addBadLink( $title ) {
  70                 if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
  71                         $this->mBadLinks[$title] = 1;
  72                 }
  73         }
  74
  75         function addImageLink( $title ) {
  76                 if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
  77         }
  78
  79         function addImageLinkObj( $nt ) {
  80                 if ( $this->mActive ) { $this->mImageLinks[$nt->getDBkey()] = 1; }
  81         }
  82
  83         function addCategoryLink( $title, $sortkey ) {
  84                 if ( $this->mActive ) { $this->mCategoryLinks[$title] = $sortkey; }
  85         }
  86
  87         function addCategoryLinkObj( &$nt, $sortkey ) {
  88                 $this->addCategoryLink( $nt->getDBkey(), $sortkey );
  89         }
  90
  91         function clearBadLink( $title ) {
  92                 unset( $this->mBadLinks[$title] );
  93                 $this->clearLink( $title );
  94         }
  95
  96         function clearLink( $title ) {
  97                 global $wgMemc, $wgLinkCacheMemcached;
  98                 if( $wgLinkCacheMemcached )
  99                         $wgMemc->delete( $this->getKey( $title ) );
 100         }
 101
 102         function suspend() { $this->mActive = false; }
 103         function resume() { $this->mActive = true; }
 104         function getGoodLinks() { return $this->mGoodLinks; }
 105         function getBadLinks() { return array_keys( $this->mBadLinks ); }
 106         function getImageLinks() { return $this->mImageLinks; }
 107         function getCategoryLinks() { return $this->mCategoryLinks; }
 108
 109         function addLink( $title ) {
 110                 $nt = Title::newFromDBkey( $title );
 111                 if( $nt ) {
 112                         return $this->addLinkObj( $nt );
 113                 } else {
 114                         return 0;
 115                 }
 116         }
 117
 118         function addLinkObj( &$nt ) {
 119                 global $wgMemc, $wgLinkCacheMemcached;
 120                 $title = $nt->getPrefixedDBkey();
 121                 if ( $this->isBadLink( $title ) ) { return 0; }
 122                 $id = $this->getGoodLinkID( $title );
 123                 if ( 0 != $id ) { return $id; }
 124
 125                 $fname = 'LinkCache::addLinkObj';
 126                 wfProfileIn( $fname );
 127
 128                 $ns = $nt->getNamespace();
 129                 $t = $nt->getDBkey();
 130
 131                 if ( '' == $title ) {
 132                         wfProfileOut( $fname );
 133                         return 0;
 134                 }
 135
 136                 $id = NULL;
 137                 if( $wgLinkCacheMemcached )
 138                         $id = $wgMemc->get( $key = $this->getKey( $title ) );
 139                 if( ! is_integer( $id ) ) {
 140                         if ( $this->mForUpdate ) {
 141                                 $db =& wfGetDB( DB_MASTER );
 142                                 $options = array( 'FOR UPDATE' );
 143                         } else {
 144                                 $db =& wfGetDB( DB_SLAVE );
 145                                 $options = array();
 146                         }
 147
 148                         $id = $db->getField( 'cur', 'cur_id', array( 'cur_namespace' => $ns, 'cur_title' => $t ), $fname, $options );
 149                         if ( !$id ) {
 150                                 $id = 0;
 151                         }
 152                         if( $wgLinkCacheMemcached )
 153                                 $wgMemc->add( $key, $id, 3600*24 );
 154                 }
 155
 156                 if ( 0 == $id ) { $this->addBadLink( $title ); }
 157                 else { $this->addGoodLink( $id, $title ); }
 158                 wfProfileOut( $fname );
 159                 return $id;
 160         }
 161
 162         function preFill( &$fromtitle ) {
 163                 global $wgEnablePersistentLC;
 164
 165                 $fname = 'LinkCache::preFill';
 166                 wfProfileIn( $fname );
 167                 # Note -- $fromtitle is a Title *object*
 168
 169                 $this->suspend();
 170                 $id = $fromtitle->getArticleID();
 171                 $this->resume();
 172
 173                 if( $id == 0 ) {
 174                         wfDebug( "$fname - got id 0 for title '" . $fromtitle->getPrefixedDBkey() . "'\n" );
 175                         wfProfileOut( $fname );
 176                         return;
 177                 }
 178
 179                 if ( $wgEnablePersistentLC ) {
 180                         if( $this->fillFromLinkscc( $id ) ){
 181                                 wfProfileOut( $fname );
 182                                 return;
 183                         }
 184                 }
 185                 if ( $this->mForUpdate ) {
 186                         $db =& wfGetDB( DB_MASTER );
 187                         $options = 'FOR UPDATE';
 188                 } else {
 189                         $db =& wfGetDB( DB_SLAVE );
 190                         $options = '';
 191                 }
 192
 193                 $cur = $db->tableName( 'cur' );
 194                 $links = $db->tableName( 'links' );
 195
 196                 $sql = "SELECT cur_id,cur_namespace,cur_title
 197                         FROM $cur,$links
 198                         WHERE cur_id=l_to AND l_from=$id $options";
 199                 $res = $db->query( $sql, $fname );
 200                 while( $s = $db->fetchObject( $res ) ) {
 201                         $this->addGoodLink( $s->cur_id,
 202                                 Title::makeName( $s->cur_namespace, $s->cur_title )
 203                                 );
 204                 }
 205
 206                 $res = $db->select( 'brokenlinks', array( 'bl_to' ), array( 'bl_from' => $id ), $fname, array( $options ) );
 207                 while( $s = $db->fetchObject( $res ) ) {
 208                         $this->addBadLink( $s->bl_to );
 209                 }
 210
 211                 $this->mOldBadLinks = $this->mBadLinks;
 212                 $this->mOldGoodLinks = $this->mGoodLinks;
 213                 $this->mPreFilled = true;
 214
 215                 if ( $wgEnablePersistentLC ) {
 216                         $this->saveToLinkscc( $id );
 217                 }
 218                 wfProfileOut( $fname );
 219         }
 220
 221         function getGoodAdditions() {
 222                 return array_diff( $this->mGoodLinks, $this->mOldGoodLinks );
 223         }
 224
 225         function getBadAdditions() {
 226                 #wfDebug( "mOldBadLinks: " . implode( ', ', array_keys( $this->mOldBadLinks ) ) . "\n" );
 227                 #wfDebug( "mBadLinks: " . implode( ', ', array_keys( $this->mBadLinks ) ) . "\n" );
 228                 return array_values( array_diff( array_keys( $this->mBadLinks ), array_keys( $this->mOldBadLinks ) ) );
 229         }
 230
 231         function getImageAdditions() {
 232                 return array_diff_assoc( $this->mImageLinks, $this->mOldImageLinks );
 233         }
 234
 235         function getGoodDeletions() {
 236                 return array_diff( $this->mOldGoodLinks, $this->mGoodLinks );
 237         }
 238
 239         function getBadDeletions() {
 240                 return array_values( array_diff( array_keys( $this->mOldBadLinks ), array_keys( $this->mBadLinks ) ));
 241         }
 242
 243         function getImageDeletions() {
 244                 return array_diff_assoc( $this->mOldImageLinks, $this->mImageLinks );
 245         }
 246
 247         /**
 248          * Parameters:
 249          * @param $which is one of the LINKCACHE_xxx constants
 250          * @param $del,$add are the incremental update arrays which will be filled.
 251          *
 252          * @return Returns whether or not it's worth doing the incremental version.
 253          *
 254          * For example, if [[List of mathematical topics]] was blanked,
 255          * it would take a long, long time to do incrementally.
 256          */
 257         function incrementalSetup( $which, &$del, &$add ) {
 258                 if ( ! $this->mPreFilled ) {
 259                         return false;
 260                 }
 261
 262                 switch ( $which ) {
 263                         case LINKCACHE_GOOD:
 264                                 $old =& $this->mOldGoodLinks;
 265                                 $cur =& $this->mGoodLinks;
 266                                 $del = $this->getGoodDeletions();
 267                                 $add = $this->getGoodAdditions();
 268                                 break;
 269                         case LINKCACHE_BAD:
 270                                 $old =& $this->mOldBadLinks;
 271                                 $cur =& $this->mBadLinks;
 272                                 $del = $this->getBadDeletions();
 273                                 $add = $this->getBadAdditions();
 274                                 break;
 275                         default: # LINKCACHE_IMAGE
 276                                 return false;
 277                 }
 278
 279                 return true;
 280         }
 281
 282         /**
 283          * Clears cache but leaves old preFill copies alone
 284          */
 285         function clear() {
 286                 $this->mGoodLinks = array();
 287                 $this->mBadLinks = array();
 288                 $this->mImageLinks = array();
 289         }
 290
 291         /**
 292          * @access private
 293          */
 294         function fillFromLinkscc( $id ){
 295                 $fname = 'LinkCache::fillFromLinkscc';
 296
 297                 $id = IntVal( $id );
 298                 if ( $this->mForUpdate ) {
 299                         $db =& wfGetDB( DB_MASTER );
 300                         $options = 'FOR UPDATE';
 301                 } else {
 302                         $db =& wfGetDB( DB_SLAVE );
 303                         $options = '';
 304                 }
 305                 $raw = $db->getField( 'linkscc', 'lcc_cacheobj', array( 'lcc_pageid' => $id ), $fname, $options );
 306                 if ( $raw === false ) {
 307                         return false;
 308                 }
 309
 310                 $cacheobj = false;
 311                 if( function_exists( 'gzuncompress' ) )
 312                         $cacheobj = @gzuncompress( $raw );
 313
 314                 if($cacheobj == FALSE){
 315                         $cacheobj = $raw;
 316                 }
 317                 $cc = @unserialize( $cacheobj );
 318                 if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
 319                         $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
 320                         $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
 321                         $this->mPreFilled = true;
 322                         return TRUE;
 323                 } else {
 324                         return FALSE;
 325                 }
 326
 327         }
 328
 329         /**
 330          * @access private
 331          */
 332         function saveToLinkscc( $pid ){
 333                 global $wgCompressedPersistentLC;
 334                 if( $wgCompressedPersistentLC and function_exists( 'gzcompress' ) ) {
 335                         $ser = gzcompress( serialize( $this ), 3 );
 336                 } else {
 337                         $ser = serialize( $this );
 338                 }
 339                 $db =& wfGetDB( DB_MASTER );
 340                 $db->replace( 'linkscc', array( 'lcc_pageid' ), array( 'lcc_pageid' => $pid, 'lcc_cacheobj' => $ser ) );
 341         }
 342
 343         /**
 344          * Delete linkscc rows which link to here
 345          * @param $pid is a page id
 346          * @static
 347          */
 348         function linksccClearLinksTo( $pid ){
 349                 global $wgEnablePersistentLC;
 350                 if ( $wgEnablePersistentLC ) {
 351                         $fname = 'LinkCache::linksccClearLinksTo';
 352                         $pid = intval( $pid );
 353                         $dbw =& wfGetDB( DB_MASTER );
 354                         # Delete linkscc rows which link to here
 355                         $dbw->deleteJoin( 'linkscc', 'links', 'lcc_pageid', 'l_from', array( 'l_to' => $pid ), $fname );
 356                         # Delete linkscc row representing this page
 357                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ), $fname);
 358                 }
 359
 360         }
 361
 362         /**
 363          * Delete linkscc rows with broken links to here
 364          * @param $title is a prefixed db title for example like Title->getPrefixedDBkey() returns.
 365          * @static
 366          */
 367         function linksccClearBrokenLinksTo( $title ){
 368                 global $wgEnablePersistentLC;
 369                 $fname = 'LinkCache::linksccClearBrokenLinksTo';
 370
 371                 if ( $wgEnablePersistentLC ) {
 372                         $dbw =& wfGetDB( DB_MASTER );
 373                         $dbw->deleteJoin( 'linkscc', 'brokenlinks', 'lcc_pageid', 'bl_from', array( 'bl_to' => $title ), $fname );
 374                 }
 375         }
 376
 377         /**
 378          * @param $pid is a page id
 379          * @static
 380          */
 381         function linksccClearPage( $pid ){
 382                 global $wgEnablePersistentLC;
 383                 if ( $wgEnablePersistentLC ) {
 384                         $pid = intval( $pid );
 385                         $dbw =& wfGetDB( DB_MASTER );
 386                         $dbw->delete( 'linkscc', array( 'lcc_pageid' => $pid ) );
 387                 }
 388         }
 389 }
 390 ?>