MediaWiki namespace handling, mostly consolidated from GlobalFunctions.php and Articl...

diff --git a/includes/MessageCache.php b/includes/MessageCache.php
new file mode 100755 (executable)
index 0000000..3226653
--- /dev/null
+++ b/includes/MessageCache.php
@@ -0,0 +1,200 @@
+<?
+
+# Message cache
+# Performs various useful MediaWiki namespace-related functions
+
+define( "MSG_LOAD_TIMEOUT", 60);
+define( "MSG_LOCK_TIMEOUT", 10);
+define( "MSG_WAIT_TIMEOUT", 10);
+
+class MessageCache
+{
+       var $mCache, $mUseCache, $mDisable, $mExpiry;
+       var $mMemcKey, $mKeys;
+
+       function MessageCache( $useMemCached, $useDB, $expiry, $memcPrefix ) {
+               $this->initialise( $useMemCached, $useDB, $expiry, $memcPrefix );
+       }
+
+       function initialise( $useMemCached, $useDB, $expiry, $memcPrefix ) {
+               $this->mUseCache = $useMemCached;
+               $this->mDisable = !$useDB;
+               $this->mExpiry = $expiry;
+               $this->mMemcKey = "$memcPrefix:messages";
+               $this->mKeys = false; # initialised on demand
+               
+               $this->load();
+       }
+
+       # Loads messages either from memcached or the database, if not disabled
+       # On error, quietly switches to a fallback mode
+       # Returns false for a reportable error, true otherwise
+       function load() {
+               global $wgAllMessagesEn, $wgMemc;
+               
+               if ( $this->mDisable ) {
+                       return true;
+               }
+               
+               $success = true;
+               
+               if ( $this->mUseCache ) {
+                       $this->mCache = $wgMemc->get( $this->mMemcKey );
+                       
+                       # If there's nothing in memcached, load all the messages from the database
+                       if ( !$this->mCache ) {
+                               $this->lock();
+                               # Other threads don't need to load the messages if another thread is doing it.
+                               $wgMemc->set( $this->mMemcKey, "loading", MSG_LOAD_TIMEOUT );
+                               $this->loadFromDB();
+                               # Save in memcached
+                               if ( !$wgMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry ) ) {
+                                       # Hack for slabs reassignment problem
+                                       $wgMemc->set( $this->mMemcKey, "error" );
+                                       wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
+                               }
+                               $this->unlock();
+                       }
+                       
+                       if ( !is_array( $this->mCache ) ) {
+                               # If it is 'loading' or 'error', switch to individual message mode, otherwise disable
+                               if ( $this->mCache == "loading" ) {
+                                       $this->mUseCache = false;
+                               } elseif ( $this->mCache == "error" ) {
+                                       $this->mUseCache = false;
+                                       $success = false;
+                               } else {
+                                       $this->mDisable = true;
+                                       $success = false;
+                               }
+                               $this->mCache = false;
+                       }
+               }
+               return $success;
+       }
+
+       # Loads all cacheable messages from the database
+       function loadFromDB()
+       {
+               $sql = "SELECT cur_title,cur_text FROM cur WHERE cur_namespace=" . NS_MEDIAWIKI;
+               $sql .= " AND cur_title IN ('";
+               $sql .= implode( "','", $this->getKeys() ) . "')";
+               wfDebug( "$sql\n" );
+
+               $res = wfQuery( $sql, DB_READ, $fname );
+               
+               $this->mCache = array();
+               for ( $row = wfFetchObject( $res ); $row; $row = wfFetchObject( $res ) ) {
+                       $this->mCache[$row->cur_title] = $row->cur_text;
+               }
+
+               wfDebug( var_export( $this->mCache, true ) );
+
+               wfFreeResult( $res );
+       }
+       
+       function getKeys() {
+               global $wgAllMessagesEn;
+               if ( !$this->mKeys ) {
+                       $this->mKeys = array_map( 'ucfirst', array_keys( $wgAllMessagesEn ) );
+               }
+               return $this->mKeys;
+       }
+       
+       function isCacheable( $key ) {
+               global $wgAllMessagesEn;
+               return array_key_exists( lcfirst( $key ), $wgAllMessagesEn ) || 
+                       array_key_exists( $key, $wgAllMessagesEn );
+       }
+
+       function replace( $title, $text ) {
+               global $wgMemc;
+               if ( $this->isCacheable( $title ) ) {
+                       $this->lock();
+                       $this->load();
+                       if ( is_array( $this->mCache ) ) {
+                               $this->mCache[$title] = $text;
+                               $wgMemc->set( $this->mMemcKey, $this->mCache, $this->mExpiry );
+                       }
+                       $this->unlock();
+               }
+       }
+
+       # Returns success
+       # Represents a write lock on the messages key
+       function lock() {
+               global $wgMemc;
+
+               if ( !$this->mUseCache ) {
+                       return true;
+               }
+
+               $lockKey = $this->mMemcKey . "lock";
+               for ($i=0; $i < MSG_WAIT_TIMEOUT && !$wgMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT ); $i++ ) {
+                       sleep(1);
+               }
+               
+               return $i >= MSG_WAIT_TIMEOUT;
+       }
+       
+       function unlock() {
+               global $wgMemc;
+               
+               if ( !$this->mUseCache ) {
+                       return;
+               }
+
+               $lockKey = $this->mMemcKey . "lock";
+               $wgMemc->delete( $lockKey );
+       }
+       
+       function get( $key, $useDB ) {
+               global $wgLang, $wgLanguageCode;
+
+               if ( $this->mDisable ) {
+                       return $wgLang->getMessage( $key );
+               }
+               $title = ucfirst( $key );
+               
+               $message = false;
+
+               # Try the cache
+               if ( $this->mUseCache && $this->mCache ) {
+                       $message = $this->mCache[$title];
+               }
+               
+               # If it wasn't in the cache, load each message from the DB individually
+               if ( !$message && $useDB) {
+                       $sql = "SELECT cur_text FROM cur WHERE cur_namespace=" . NS_MEDIAWIKI . 
+                               " AND cur_title='$title'";
+                       $res = wfQuery( $sql, DB_READ, $fname );
+
+                       if ( wfNumRows( $res ) ) {
+                               $obj = wfFetchObject( $res );
+                               $message = $obj->cur_text;
+                               wfFreeResult( $res );
+                       }
+               }
+
+               # Try the array in $wgLang
+               if ( !$message ) {
+                       $message = $wgLang->getMessage( $key );
+               } 
+
+               # Try the English array
+               if ( !$message && $wgLanguageCode != "en" ) {
+                       $message = Language::getMessage( $key );
+               }
+               
+               # Final fallback
+               if ( !$message ) {
+                       $message = "&lt;$key&gt;";
+               }
+               return $message;
+       }
+}
+
+function lcfirst( $s ) {
+       return strtolower( $s{0}  ). substr( $s, 1 );
+}
+?>