add method to OC_Cache to check whether a fast cache (apc/xdebug/etc) is available

lib/cache.php

@@ -7,9 +7,20 @@
  */
 
 class OC_Cache {
+	/**
+	 * @var OC_Cache $user_cache
+	 */
 	static protected $user_cache;
+	/**
+	 * @var OC_Cache $global_cache
+	 */
 	static protected $global_cache;
+	static protected $isFast=null;
 
+	/**
+	 * get the global cache
+	 * @return OC_Cache
+	 */
 	static public function getGlobalCache() {
 		if (!self::$global_cache) {
 			$fast_cache = null;
@@ -27,6 +38,10 @@ class OC_Cache {
 		return self::$global_cache;
 	}
 
+	/**
+	 * get the user cache
+	 * @return OC_Cache
+	 */
 	static public function getUserCache() {
 		if (!self::$user_cache) {
 			$fast_cache = null;
@@ -44,11 +59,19 @@ class OC_Cache {
 		return self::$user_cache;
 	}
 
+	/**
+	 * get a value from the user cache
+	 * @return mixed
+	 */
 	static public function get($key) {
 		$user_cache = self::getUserCache();
 		return $user_cache->get($key);
 	}
 
+	/**
+	 * set a value in the user cache
+	 * @return bool
+	 */
 	static public function set($key, $value, $ttl=0) {
 		if (empty($key)) {
 			return false;
@@ -57,19 +80,42 @@ class OC_Cache {
 		return $user_cache->set($key, $value, $ttl);
 	}
 
+	/**
+	 * check if a value is set in the user cache
+	 * @return bool
+	 */
 	static public function hasKey($key) {
 		$user_cache = self::getUserCache();
 		return $user_cache->hasKey($key);
 	}
 
+	/**
+	 * remove an item from the user cache
+	 * @return bool
+	 */
 	static public function remove($key) {
 		$user_cache = self::getUserCache();
 		return $user_cache->remove($key);
 	}
 
+	/**
+	 * clear the user cache
+	 * @return bool
+	 */
 	static public function clear() {
 		$user_cache = self::getUserCache();
 		return $user_cache->clear();
 	}
 
+	/**
+	 * check if a fast memory based cache is available
+	 * @return true
+	 */
+	static public function isFast() {
+		if(is_null(self::$isFast)){
+			self::$isFast=function_exists('xcache_set') || function_exists('apc_store');
+		}
+		return self::$isFast;
+	}
+
 }