10 files changed, 94 insertions, 24 deletions
diff --git a/phpBB/includes/cache/driver/apc.php b/phpBB/includes/cache/driver/apc.php
index dc0144fac3..0516b669c8 100644
--- a/phpBB/includes/cache/driver/apc.php
+++ b/phpBB/includes/cache/driver/apc.php
@@ -26,7 +26,7 @@ class phpbb_cache_driver_apc extends phpbb_cache_driver_memory
 	/**
 	* Purge cache data
 	*
-	* @return void
+	* @return null
 	*/
 	function purge()
 	{
diff --git a/phpBB/includes/cache/driver/eaccelerator.php b/phpBB/includes/cache/driver/eaccelerator.php
index 7939f043c9..257b90c76e 100644
--- a/phpBB/includes/cache/driver/eaccelerator.php
+++ b/phpBB/includes/cache/driver/eaccelerator.php
@@ -30,7 +30,7 @@ class phpbb_cache_driver_eaccelerator extends phpbb_cache_driver_memory
 	/**
 	* Purge cache data
 	*
-	* @return void
+	* @return null
 	*/
 	function purge()
 	{
@@ -47,7 +47,7 @@ class phpbb_cache_driver_eaccelerator extends phpbb_cache_driver_memory
 	/**
 	 * Perform cache garbage collection
 	 *
-	 * @return void
+	 * @return null
 	 */
 	function tidy()
 	{
diff --git a/phpBB/includes/cache/driver/file.php b/phpBB/includes/cache/driver/file.php
index 5014ba18af..691abe0438 100644
--- a/phpBB/includes/cache/driver/file.php
+++ b/phpBB/includes/cache/driver/file.php
@@ -388,10 +388,10 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 
 		if ($this->_write('sql_' . md5($query), $this->sql_rowset[$query_id], $ttl + time(), $query))
 		{
-			$query_result = $query_id;
+			return $query_id;
 		}
 
-		return $query_id;
+		return $query_result;
 	}
 
 	/**
@@ -653,10 +653,11 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 
 		$file = "{$this->cache_dir}$filename.$phpEx";
 
+		$lock = new phpbb_lock_flock($file);
+		$lock->acquire();
+
 		if ($handle = @fopen($file, 'wb'))
 		{
-			@flock($handle, LOCK_EX);
-
 			// File header
 			fwrite($handle, '<' . '?php exit; ?' . '>');
 
@@ -697,7 +698,6 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 				fwrite($handle, $data);
 			}
 
-			@flock($handle, LOCK_UN);
 			fclose($handle);
 
 			if (!function_exists('phpbb_chmod'))
@@ -708,10 +708,16 @@ class phpbb_cache_driver_file extends phpbb_cache_driver_base
 
 			phpbb_chmod($file, CHMOD_READ | CHMOD_WRITE);
 
-			return true;
+			$return_value = true;
+		}
+		else
+		{
+			$return_value = false;
 		}
 
-		return false;
+		$lock->release();
+
+		return $return_value;
 	}
 
 	/**
diff --git a/phpBB/includes/cache/driver/interface.php b/phpBB/includes/cache/driver/interface.php
index 847ba97262..d403bbcd71 100644
--- a/phpBB/includes/cache/driver/interface.php
+++ b/phpBB/includes/cache/driver/interface.php
@@ -63,42 +63,81 @@ interface phpbb_cache_driver_interface
 	public function destroy($var_name, $table = '');
 
 	/**
-	* Check if a given cache entry exist
+	* Check if a given cache entry exists
 	*/
 	public function _exists($var_name);
 
 	/**
-	* Load cached sql query
+	* Load result of an SQL query from cache.
+	*
+	* @param string $query			SQL query
+	*
+	* @return int|bool				Query ID (integer) if cache contains a rowset
+	*								for the specified query.
+	*								False otherwise.
 	*/
 	public function sql_load($query);
 
 	/**
-	* Save sql query
+	* Save result of an SQL query in cache.
+	*
+	* In persistent cache stores, this function stores the query
+	* result to persistent storage. In other words, there is no need
+	* to call save() afterwards.
+	*
+	* @param string $query			SQL query, should be used for generating storage key
+	* @param mixed $query_result	The result from dbal::sql_query, to be passed to
+	* 								dbal::sql_fetchrow to get all rows and store them
+	* 								in cache.
+	* @param int $ttl				Time to live, after this timeout the query should
+	*								expire from the cache.
+	* @return int|mixed				If storing in cache succeeded, an integer $query_id
+	* 								representing the query should be returned. Otherwise
+	* 								the original $query_result should be returned.
 	*/
 	public function sql_save($query, $query_result, $ttl);
 
 	/**
-	* Ceck if a given sql query exist in cache
+	* Check if result for a given SQL query exists in cache.
+	*
+	* @param int $query_id
+	* @return bool
 	*/
 	public function sql_exists($query_id);
 
 	/**
 	* Fetch row from cache (database)
+	*
+	* @param int $query_id
+	* @return array|bool 			The query result if found in the cache, otherwise
+	* 								false.
 	*/
 	public function sql_fetchrow($query_id);
 
 	/**
 	* Fetch a field from the current row of a cached database result (database)
+	*
+	* @param int $query_id
+	* @param $field 				The name of the column.
+	* @return string|bool 			The field of the query result if found in the cache,
+	* 								otherwise false.
 	*/
 	public function sql_fetchfield($query_id, $field);
 
 	/**
 	* Seek a specific row in an a cached database result (database)
+	*
+	* @param int $rownum 			Row to seek to.
+	* @param int $query_id
+	* @return bool
 	*/
 	public function sql_rowseek($rownum, $query_id);
 
 	/**
 	* Free memory used for a cached database result (database)
+	*
+	* @param int $query_id
+	* @return bool
 	*/
 	public function sql_freeresult($query_id);
 }
diff --git a/phpBB/includes/cache/driver/memcache.php b/phpBB/includes/cache/driver/memcache.php
index 9fe70f8b44..3fd16b23b0 100644
--- a/phpBB/includes/cache/driver/memcache.php
+++ b/phpBB/includes/cache/driver/memcache.php
@@ -64,7 +64,7 @@ class phpbb_cache_driver_memcache extends phpbb_cache_driver_memory
 	/**
 	* Unload the cache resources
 	*
-	* @return void
+	* @return null
 	*/
 	function unload()
 	{
@@ -76,7 +76,7 @@ class phpbb_cache_driver_memcache extends phpbb_cache_driver_memory
 	/**
 	* Purge cache data
 	*
-	* @return void
+	* @return null
 	*/
 	function purge()
 	{
diff --git a/phpBB/includes/cache/driver/memory.php b/phpBB/includes/cache/driver/memory.php
index f6c42c0ea6..c39f9f7850 100644
--- a/phpBB/includes/cache/driver/memory.php
+++ b/phpBB/includes/cache/driver/memory.php
@@ -299,7 +299,7 @@ abstract class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 		if (!preg_match('/FROM \\(?(`?\\w+`?(?: \\w+)?(?:, ?`?\\w+`?(?: \\w+)?)*)\\)?/', $query, $regs))
 		{
 			// Bail out if the match fails.
-			return;
+			return $query_result;
 		}
 		$tables = array_map('trim', explode(',', $regs[1]));
 
@@ -339,8 +339,6 @@ abstract class phpbb_cache_driver_memory extends phpbb_cache_driver_base
 
 		$this->_write('sql_' . $hash, $this->sql_rowset[$query_id], $ttl);
 
-		$query_result = $query_id;
-
 		return $query_id;
 	}
 
diff --git a/phpBB/includes/cache/driver/null.php b/phpBB/includes/cache/driver/null.php
index df2c6c026f..687604d14f 100644
--- a/phpBB/includes/cache/driver/null.php
+++ b/phpBB/includes/cache/driver/null.php
@@ -109,6 +109,7 @@ class phpbb_cache_driver_null extends phpbb_cache_driver_base
 	*/
 	function sql_save($query, $query_result, $ttl)
 	{
+		return $query_result;
 	}
 
 	/**
diff --git a/phpBB/includes/cache/driver/redis.php b/phpBB/includes/cache/driver/redis.php
index a768885962..960735b673 100644
--- a/phpBB/includes/cache/driver/redis.php
+++ b/phpBB/includes/cache/driver/redis.php
@@ -39,13 +39,39 @@ class phpbb_cache_driver_redis extends phpbb_cache_driver_memory
 
 	var $redis;
 
+	/**
+	* Creates a redis cache driver.
+	*
+	* The following global constants affect operation:
+	*
+	* PHPBB_ACM_REDIS_HOST
+	* PHPBB_ACM_REDIS_PORT
+	* PHPBB_ACM_REDIS_PASSWORD
+	* PHPBB_ACM_REDIS_DB
+	*
+	* There are no publicly documented constructor parameters.
+	*/
 	function __construct()
 	{
 		// Call the parent constructor
 		parent::__construct();
 
 		$this->redis = new Redis();
-		$this->redis->connect(PHPBB_ACM_REDIS_HOST, PHPBB_ACM_REDIS_PORT);
+
+		$args = func_get_args();
+		if (!empty($args))
+		{
+			$ok = call_user_func_array(array($this->redis, 'connect'), $args);
+		}
+		else
+		{
+			$ok = $this->redis->connect(PHPBB_ACM_REDIS_HOST, PHPBB_ACM_REDIS_PORT);
+		}
+
+		if (!$ok)
+		{
+			trigger_error('Could not connect to redis server');
+		}
 
 		if (defined('PHPBB_ACM_REDIS_PASSWORD'))
 		{
@@ -74,7 +100,7 @@ class phpbb_cache_driver_redis extends phpbb_cache_driver_memory
 	/**
 	* Unload the cache resources
 	*
-	* @return void
+	* @return null
 	*/
 	function unload()
 	{
@@ -86,7 +112,7 @@ class phpbb_cache_driver_redis extends phpbb_cache_driver_memory
 	/**
 	* Purge cache data
 	*
-	* @return void
+	* @return null
 	*/
 	function purge()
 	{
diff --git a/phpBB/includes/cache/driver/wincache.php b/phpBB/includes/cache/driver/wincache.php
index fa9eb95f88..58f3b4a581 100644
--- a/phpBB/includes/cache/driver/wincache.php
+++ b/phpBB/includes/cache/driver/wincache.php
@@ -26,7 +26,7 @@ class phpbb_cache_driver_wincache extends phpbb_cache_driver_memory
 	/**
 	* Purge cache data
 	*
-	* @return void
+	* @return null
 	*/
 	function purge()
 	{
diff --git a/phpBB/includes/cache/driver/xcache.php b/phpBB/includes/cache/driver/xcache.php
index 0b768bdb3e..06c5fafd97 100644
--- a/phpBB/includes/cache/driver/xcache.php
+++ b/phpBB/includes/cache/driver/xcache.php
@@ -41,7 +41,7 @@ class phpbb_cache_driver_xcache extends phpbb_cache_driver_memory
 	/**
 	* Purge cache data
 	*
-	* @return void
+	* @return null
 	*/
 	function purge()
 	{