Adding multihost - locking

Adding Unit-Tests for it

src/Core/Cache/RedisCacheDriver.php

@@ -11,7 +11,7 @@ use Friendica\Core\Cache;
  * @author Hypolite Petovan <mrpetovan@gmail.com>
  * @author Roland Haeder <roland@mxchange.org>
  */
-class RedisCacheDriver extends BaseObject implements ICacheDriver
+class RedisCacheDriver extends BaseObject implements IMemoryCacheDriver
 {
 	/**
 	 * @var Redis
@@ -55,14 +55,21 @@ class RedisCacheDriver extends BaseObject implements ICacheDriver
 		return $return;
 	}
 
-	public function set($key, $value, $duration = Cache::MONTH)
+	public function set($key, $value, $ttl = Cache::FIVE_MINUTES)
 	{
 		// We store with the hostname as key to avoid problems with other applications
-		return $this->redis->set(
-			self::getApp()->get_hostname() . ":" . $key,
-			serialize($value),
-			time() + $duration
-		);
+		if ($ttl > 0) {
+			return $this->redis->setex(
+				self::getApp()->get_hostname() . ":" . $key,
+				time() + $ttl,
+				serialize($value)
+			);
+		} else {
+			return $this->redis->set(
+				self::getApp()->get_hostname() . ":" . $key,
+				serialize($value)
+			);
+		}
 	}
 
 	public function delete($key)
@@ -74,4 +81,75 @@ class RedisCacheDriver extends BaseObject implements ICacheDriver
 	{
 		return true;
 	}
+
+
+	/**
+	 * @brief Sets a value if it's not already stored
+	 *
+	 * @param string $key The cache key
+	 * @param mixed $value The old value we know from the cache
+	 * @param int    $ttl      The cache lifespan, must be one of the Cache constants
+	 * @return bool
+	 */
+	public function add($key, $value, $ttl = Cache::FIVE_MINUTES)
+	{
+		if (!is_int($value)) {
+			$value = serialize($value);
+		}
+
+		return $this->redis->setnx(self::getApp()->get_hostname() . ":" . $key, $value);
+	}
+
+	/**
+	 * @brief Compares if the old value is set and sets the new value
+	 *
+	 * @param string $key The cache key
+	 * @param mixed $oldValue The old value we know
+	 * @param mixed $newValue The new value we want to set
+	 * @param int    $ttl      The cache lifespan, must be one of the Cache constants
+	 * @return bool
+	 */
+	public function compareSet($key, $oldValue, $newValue, $ttl = Cache::FIVE_MINUTES)
+	{
+		if (!is_int($newValue)) {
+			$newValue = serialize($newValue);
+		}
+
+		$this->redis->watch(self::getApp()->get_hostname() . ":" . $key);
+		// If the old value isn't what we expected, somebody else changed the key meanwhile
+		if ($this->get($key) === $oldValue) {
+			if ($ttl > 0) {
+				$result = $this->redis->multi()
+					->setex(self::getApp()->get_hostname() . ":" . $ttl, $key, $newValue)
+					->exec();
+			} else {
+				$result = $this->redis->multi()
+					->set(self::getApp()->get_hostname() . ":" . $key, $newValue)
+					->exec();
+			}
+			return $result !== false;
+		}
+		$this->redis->unwatch();
+		return false;
+	}
+	/**
+	 * @brief Compares if the old value is set and removes it
+	 *
+	 * @param string $key The cache key
+	 * @param mixed $value The old value we know and want to delete
+	 * @return bool
+	 */
+	public function compareDelete($key, $value)
+	{
+		$this->redis->watch(self::getApp()->get_hostname() . ":" . $key);
+		// If the old value isn't what we expected, somebody else changed the key meanwhile
+		if ($this->get($key) === $value) {
+			$result = $this->redis->multi()
+				->del(self::getApp()->get_hostname() . ":" . $key)
+				->exec();
+			return $result !== false;
+		}
+		$this->redis->unwatch();
+		return false;
+	}
 }