Added versioning to serialized LinkCache objects. Added pref.

diff --git a/includes/LinkCache.php b/includes/LinkCache.php
index 108f887..7332524 100644 (file)
--- a/includes/LinkCache.php
+++ b/includes/LinkCache.php
@@ -6,7 +6,10 @@ define ('LINKCACHE_GOOD', 0);
 define ('LINKCACHE_BAD', 1);
 define ('LINKCACHE_IMAGE', 2);
 
-class LinkCache {
+class LinkCache {      
+       // Increment $mClassVer whenever old serialized versions of this class
+       // becomes incompatible with the new version.
+       /* private */ var $mClassVer = 1; 
 
        /* private */ var $mGoodLinks, $mBadLinks, $mActive;
        /* private */ var $mImageLinks; 
@@ -140,7 +143,7 @@ class LinkCache {
 
        function preFill( &$fromtitle )
        {
-               global $wgEnablePersistentLC;
+               global $wgEnablePersistentLC, $wgCompressedPersistentLC;
 
                $fname = "LinkCache::preFill";
                wfProfileIn( $fname );
@@ -148,12 +151,8 @@ class LinkCache {
                $dbkeyfrom = wfStrencode( $fromtitle->getPrefixedDBKey() );
 
                if ( $wgEnablePersistentLC ) {
-                       $res = wfQuery("SELECT lcc_cacheobj FROM linkscc WHERE lcc_title = '{$dbkeyfrom}'", 
-                               DB_READ);
-                       $row = wfFetchObject( $res );
-                       if( $row != FALSE){
-                               $cacheobj = gzuncompress( $row->lcc_cacheobj );
-                               $cc = unserialize( $cacheobj );
+                       $cc =& $this->getFromLinkscc( $dbkeyfrom );
+                       if( $cc != FALSE ){
                                $this->mOldGoodLinks = $this->mGoodLinks = $cc->mGoodLinks;
                                $this->mOldBadLinks = $this->mBadLinks = $cc->mBadLinks;
                                $this->mPreFilled = true;
@@ -192,8 +191,12 @@ class LinkCache {
 
                if ( $wgEnablePersistentLC ) {
                        // put fetched link data into cache
-                       $serCachegz = wfStrencode( gzcompress( serialize( $this ), 3) );
-                       wfQuery("REPLACE INTO linkscc VALUES({$id}, '{$dbkeyfrom}', '{$serCachegz}')", 
+                       if( $wgCompressedPersistentLC and function_exists( "gzcompress" ) ) {
+                               $ser = wfStrencode( gzcompress( serialize( $this ), 3 ));
+                       } else {
+                               $ser = wfStrencode( serialize( $this ) );
+                       }
+                       wfQuery("REPLACE INTO linkscc VALUES({$id}, '{$dbkeyfrom}', '{$ser}')", 
                                DB_WRITE);
                                wfDebug( "LinkCache::preFill - saved to linkscc\n" );
                }
@@ -270,6 +273,28 @@ class LinkCache {
                $this->mBadLinks = array();
                $this->mImageLinks = array();
        }
-       
+
+
+       function &getFromLinkscc( $dbkeyfrom ){
+               $res = wfQuery("SELECT lcc_cacheobj FROM linkscc WHERE lcc_title = '{$dbkeyfrom}'", 
+                       DB_READ);
+               $row = wfFetchObject( $res );
+               if( $row == FALSE)
+                       return false;   
+
+               $cacheobj = false;
+               if( function_exists( "gzuncompress" ) )
+                       $cacheobj = @gzuncompress( $row->lcc_cacheobj );
+
+               if($cacheobj == FALSE){
+                       $cacheobj = $row->lcc_cacheobj;
+               }
+               $cc = @unserialize( $cacheobj );
+               if( isset( $cc->mClassVer ) and ($cc->mClassVer == $this->mClassVer ) ){
+                       return $cc;
+               } else {
+                       return FALSE;
+               }
+       }
 }
 ?>