From: Tim Starling <tstarling@users.mediawiki.org>
Date: Sun, 14 Dec 2003 14:32:19 +0000 (+0000)
Subject: MediaWiki namespace handling, mostly consolidated from GlobalFunctions.php and Articl... 
X-Git-Tag: 1.3.0beta1~1243
X-Git-Url: https://git.cyclocoop.org/%27.WWW_URL.%27admin/config/%7B%24admin_url%7D?a=commitdiff_plain;h=edf6b38626;p=lhc%2Fweb%2Fwiklou.git

MediaWiki namespace handling, mostly consolidated from GlobalFunctions.php and Article.php, with some enhancements
---

diff --git a/includes/MessageCache.php b/includes/MessageCache.php
new file mode 100755
index 0000000000..3226653e53
--- /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 );
+}
+?>