database: added DBConnRef wrapper to manage calling reuseConnection()

[lhc/web/wiklou.git] / includes / db / LoadBalancer.php

diff --git a/includes/db/LoadBalancer.php b/includes/db/LoadBalancer.php
index e2434a0..ab200b4 100644 (file)
--- a/includes/db/LoadBalancer.php
+++ b/includes/db/LoadBalancer.php
@@ -78,7 +78,7 @@ class LoadBalancer {
                        }
                }
 
-               foreach( $params['servers'] as $i => $server ) {
+               foreach ( $params['servers'] as $i => $server ) {
                        $this->mLoads[$i] = $server['load'];
                        if ( isset( $server['groupLoads'] ) ) {
                                foreach ( $server['groupLoads'] as $group => $ratio ) {
@@ -117,7 +117,7 @@ class LoadBalancer {
         * Given an array of non-normalised probabilities, this function will select
         * an element and return the appropriate key
         *
-        * @deprecated 1.21, use ArrayUtils::pickRandom()
+        * @deprecated since 1.21, use ArrayUtils::pickRandom()
         *
         * @param $weights array
         *
@@ -479,6 +479,7 @@ class LoadBalancer {
 
                # Operation-based index
                if ( $i == DB_SLAVE ) {
+                       $this->mLastError = 'Unknown error'; // reset error string
                        $i = $this->getReaderIndex( false, $wiki );
                        # Couldn't find a working server in getReaderIndex()?
                        if ( $i === false ) {
@@ -544,6 +545,22 @@ class LoadBalancer {
                }
        }
 
+       /**
+        * Get a database connection handle reference
+        *
+        * The handle's methods wrap simply wrap those of a DatabaseBase handle
+        *
+        * @see LoadBalancer::getConnection() for parameter information
+        *
+        * @param integer $db
+        * @param mixed $groups
+        * @param string $wiki
+        * @return DBConnRef
+        */
+       public function getConnectionRef( $db, $groups = array(), $wiki = false ) {
+               return new DBConnRef( $this, $this->getConnection( $db, $groups, $wiki ) );
+       }
+
        /**
         * Open a connection to the server given by the specified index
         * Index must be an actual index into the array.
@@ -665,7 +682,7 @@ class LoadBalancer {
         * @return bool
         */
        function isOpen( $index ) {
-               if( !is_integer( $index ) ) {
+               if ( !is_integer( $index ) ) {
                        return false;
                }
                return (bool)$this->getAnyOpenConnection( $index );
@@ -682,7 +699,7 @@ class LoadBalancer {
         * @return DatabaseBase
         */
        function reallyOpenConnection( $server, $dbNameOverride = false ) {
-               if( !is_array( $server ) ) {
+               if ( !is_array( $server ) ) {
                        throw new MWException( 'You must update your load-balancing configuration. ' .
                                'See DefaultSettings.php entry for $wgDBservers.' );
                }
@@ -833,7 +850,7 @@ class LoadBalancer {
         */
        function closeAll() {
                foreach ( $this->mConns as $conns2 ) {
-                       foreach  ( $conns2 as $conns3 ) {
+                       foreach ( $conns2 as $conns3 ) {
                                foreach ( $conns3 as $conn ) {
                                        $conn->close();
                                }
@@ -1067,3 +1084,33 @@ class LoadBalancer {
                $this->mLagTimes = null;
        }
 }
+
+/**
+ * Helper class to handle automatically marking connectons as reusable (via RAII pattern)
+ *
+ * @ingroup Database
+ * @since 1.22
+ */
+class DBConnRef {
+       /** @var LoadBalancer */
+       protected $lb;
+       /** @var DatabaseBase */
+       protected $conn;
+
+       /**
+        * @param $lb LoadBalancer
+        * @param $conn DatabaseBase
+        */
+       public function __construct( LoadBalancer $lb, DatabaseBase $conn ) {
+               $this->lb = $lb;
+               $this->conn = $conn;
+       }
+
+       public function __call( $name, $arguments ) {
+               return call_user_func_array( array( $this->conn, $name ), $arguments );
+       }
+
+       function __destruct() {
+               $this->lb->reuseConnection( $this->conn );
+       }
+}