follow-up r52858: remove unused "global $wgMessageCache;"
[lhc/web/wiklou.git] / includes / LinkCache.php
index 8664ef8..4f74cdd 100644 (file)
@@ -1,21 +1,43 @@
-<?
-# Cache for article titles and ids linked from one source
-
+<?php
+/**
+ * Cache for article titles (prefixed DB keys) and ids linked from one source
+ *
+ * @ingroup Cache
+ */
 class LinkCache {
+       // Increment $mClassVer whenever old serialized versions of this class
+       // becomes incompatible with the new version.
+       /* private */ var $mClassVer = 4;
+
+       /* private */ var $mGoodLinks, $mBadLinks;
+       /* private */ var $mForUpdate;
+
+       /**
+        * Get an instance of this class
+        */
+       static function &singleton() {
+               static $instance;
+               if ( !isset( $instance ) ) {
+                       $instance = new LinkCache;
+               }
+               return $instance;
+       }
 
-       /* private */ var $mGoodLinks, $mBadLinks, $mActive;
-       /* private */ var $mImageLinks;
-
-       function LinkCache()
-       {
-               $this->mActive = true;
+       function __construct() {
+               $this->mForUpdate = false;
                $this->mGoodLinks = array();
+               $this->mGoodLinkFields = array();
                $this->mBadLinks = array();
-               $this->mImageLinks = array();
        }
 
-       function getGoodLinkID( $title )
-       {
+       /**
+        * General accessor to get/set whether SELECT FOR UPDATE should be used
+        */
+       public function forUpdate( $update = NULL ) {
+               return wfSetVar( $this->mForUpdate, $update );
+       }
+
+       public function getGoodLinkID( $title ) {
                if ( array_key_exists( $title, $this->mGoodLinks ) ) {
                        return $this->mGoodLinks[$title];
                } else {
@@ -23,99 +45,151 @@ class LinkCache {
                }
        }
 
-       function isBadLink( $title )
-       {
-               return in_array( $title, $this->mBadLinks );
-       }
-
-       function addGoodLink( $id, $title )
-       {
-               if ( $this->mActive ) {
-                       $this->mGoodLinks[$title] = $id;
+       /**
+        * Get a field of a title object from cache.
+        * If this link is not good, it will return NULL.
+        * @param Title $title
+        * @param string $field ('length','redirect')
+        * @return mixed
+        */
+       public function getGoodLinkFieldObj( $title, $field ) {
+               $dbkey = $title->getPrefixedDbKey();
+               if ( array_key_exists( $dbkey, $this->mGoodLinkFields ) ) {
+                       return $this->mGoodLinkFields[$dbkey][$field];
+               } else {
+                       return NULL;
                }
        }
 
-       function addBadLink( $title )
-       {
-               if ( $this->mActive && ( ! $this->isBadLink( $title ) ) ) {
-                       array_push( $this->mBadLinks, $title );
-               }
+       public function isBadLink( $title ) {
+               return array_key_exists( $title, $this->mBadLinks );
        }
 
-       function addImageLink( $title )
-       {
-               if ( $this->mActive ) { $this->mImageLinks[$title] = 1; }
+       /**
+        * Add a link for the title to the link cache
+        * @param int $id
+        * @param Title $title
+        * @param int $len
+        * @param int $redir
+        */
+       public function addGoodLinkObj( $id, $title, $len = -1, $redir = NULL ) {
+               $dbkey = $title->getPrefixedDbKey();
+               $this->mGoodLinks[$dbkey] = $id;
+               $this->mGoodLinkFields[$dbkey] = array( 'length' => $len, 'redirect' => $redir );
        }
 
-       function clearBadLink( $title )
-       {
-               $index = array_search( $title, $this->mBadLinks );
-               if ( isset( $index ) ) {
-                       unset( $this->mBadLinks[$index] );
+       public function addBadLinkObj( $title ) {
+               $dbkey = $title->getPrefixedDbKey();
+               if ( !$this->isBadLink( $dbkey ) ) {
+                       $this->mBadLinks[$dbkey] = 1;
                }
        }
 
-       function suspend() { $this->mActive = false; }
-       function resume() { $this->mActive = true; }
-       function getGoodLinks() { return $this->mGoodLinks; }
-       function getBadLinks() { return $this->mBadLinks; }
-       function getImageLinks() { return $this->mImageLinks; }
-
-       function addLink( $title )
-       {
-               if ( $this->isBadLink( $title ) ) { return 0; }
-               $id = $this->getGoodLinkID( $title );
-               if ( 0 != $id ) { return $id; }
+       public function clearBadLink( $title ) {
+               unset( $this->mBadLinks[$title] );
+       }
 
-               wfProfileIn( "LinkCache::addLink-checkdatabase" );
+       public function clearLink( $title ) {
+               $dbkey = $title->getPrefixedDbKey();
+               if( isset($this->mBadLinks[$dbkey]) ) {
+                       unset($this->mBadLinks[$dbkey]);
+               }
+               if( isset($this->mGoodLinks[$dbkey]) ) {
+                       unset($this->mGoodLinks[$dbkey]);
+               }
+               if( isset($this->mGoodLinkFields[$dbkey]) ) {
+                       unset($this->mGoodLinkFields[$dbkey]);
+               }
+       }
 
+       public function getGoodLinks() { return $this->mGoodLinks; }
+       public function getBadLinks() { return array_keys( $this->mBadLinks ); }
+
+       /**
+        * Add a title to the link cache, return the page_id or zero if non-existent
+        * @param $title String: title to add
+        * @param $len int, page size
+        * @param $redir bool, is redirect?
+        * @return integer
+        */
+       public function addLink( $title, $len = -1, $redir = NULL ) {
                $nt = Title::newFromDBkey( $title );
-               $ns = $nt->getNamespace();
-               $t = $nt->getDBkey();
-
-               if ( "" == $t ) { return 0; }
-               $sql = "SELECT HIGH_PRIORITY cur_id FROM cur WHERE cur_namespace=" .
-                 "{$ns} AND cur_title='" . wfStrencode( $t ) . "'";
-               $res = wfQuery( $sql, "LinkCache::addLink" );
-
-               if ( 0 == wfNumRows( $res ) ) {
-                       $id = 0;
+               if( $nt ) {
+                       return $this->addLinkObj( $nt, $len, $redir );
                } else {
-                       $s = wfFetchObject( $res );
-                       $id = $s->cur_id;
+                       return 0;
                }
-               if ( 0 == $id ) { $this->addBadLink( $title ); }
-               else { $this->addGoodLink( $id, $title ); }
-               wfProfileOut();
-               return $id;
        }
 
-       function preFill( $fromtitle )
-       {
-               wfProfileIn( "LinkCache::preFill" );
-               # Note -- $fromtitle is a Title *object*
-               $dbkeyfrom = wfStrencode( $fromtitle->getPrefixedDBKey() );
-               $sql = "SELECT HIGH_PRIORITY cur_id,cur_namespace,cur_title
-                       FROM cur,links
-                       WHERE cur_id=l_to AND l_from='{$dbkeyfrom}'";
-               $res = wfQuery( $sql, "LinkCache::preFill" );
-               while( $s = wfFetchObject( $res ) ) {
-                       $this->addGoodLink( $s->cur_id,
-                               Title::makeName( $s->cur_namespace, $s->cur_title )
-                               );
+       /**
+        * Add a title to the link cache, return the page_id or zero if non-existent
+        * @param $nt Title to add.
+        * @param $len int, page size
+        * @param $redir bool, is redirect?
+        * @return integer
+        */
+       public function addLinkObj( &$nt, $len = -1, $redirect = NULL ) {
+               global $wgAntiLockFlags, $wgProfiler;
+               wfProfileIn( __METHOD__ );
+
+               $key = $nt->getPrefixedDBkey();
+               if ( $this->isBadLink( $key ) ) {
+                       wfProfileOut( __METHOD__ );
+                       return 0;
+               }
+               $id = $this->getGoodLinkID( $key );
+               if ( $id != 0 ) {
+                       wfProfileOut( __METHOD__ );
+                       return $id;
                }
 
-               $sql = "SELECT HIGH_PRIORITY bl_to
-                       FROM brokenlinks
-                       WHERE bl_from='{$dbkeyfrom}'";
-               $res = wfQuery( $sql, "LinkCache::preFill" );
-               while( $s = wfFetchObject( $res ) ) {
-                       $this->addBadLink( $s->bl_to );
+               if ( $key === '' ) {
+                       wfProfileOut( __METHOD__ );
+                       return 0;
+               }
+               
+               # Some fields heavily used for linking...
+               if ( $this->mForUpdate ) {
+                       $db = wfGetDB( DB_MASTER );
+                       if ( !( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) ) {
+                               $options = array( 'FOR UPDATE' );
+                       } else {
+                               $options = array();
+                       }
+               } else {
+                       $db = wfGetDB( DB_SLAVE );
+                       $options = array();
                }
 
-               wfProfileOut();
+               $s = $db->selectRow( 'page', 
+                       array( 'page_id', 'page_len', 'page_is_redirect' ),
+                       array( 'page_namespace' => $nt->getNamespace(), 'page_title' => $nt->getDBkey() ),
+                       __METHOD__, $options );
+               # Set fields...
+               if ( $s !== false ) {
+                       $id = $s->page_id;
+                       $len = $s->page_len;
+                       $redirect = $s->page_is_redirect;
+               } else {
+                       $len = -1;
+                       $redirect = 0;
+               }
+
+               if ( $id == 0 ) {
+                       $this->addBadLinkObj( $nt );
+               } else {
+                       $this->addGoodLinkObj( $id, $nt, $len, $redirect );
+               }
+               wfProfileOut( __METHOD__ );
+               return $id;
        }
 
+       /**
+        * Clears cache
+        */
+       public function clear() {
+               $this->mGoodLinks = array();
+               $this->mGoodLinkFields = array();
+               $this->mBadLinks = array();
+       }
 }
-
-?>