#12: Add expiration time for memcache lock storage

.travis.php.ini

@@ -0,0 +1,2 @@
+extension=memcache.so
+extension=memcached.so

.travis.yml

@@ -17,8 +17,7 @@ services:
  - redis-server
 
 before_script:
- - ./tests/travis/memcache-setup.sh
- - ./tests/travis/memcached-setup.sh
+ - if [[ "$TRAVIS_PHP_VERSION" != "hhvm" ]]; then cat .travis.php.ini >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini ; echo "Loading additional config for version $TRAVIS_PHP_VERSION" ; fi
  - ./tests/travis/composer-setup.sh
  - ./tests/travis/mysql-setup.sh
 

src/NinjaMutex/Lock/LockExpirationInterface.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * This file is part of ninja-mutex.
+ *
+ * (C) Kamil Dziedzic <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace NinjaMutex\Lock;
+
+/**
+ * Lock implementor
+ *
+ * @author Kamil Dziedzic <[email protected]>
+ */
+interface LockExpirationInterface
+{
+    /**
+     * @param int $expiration Expiration time of the lock in seconds.
+     */
+    public function setExpiration($expiration);
+
+    /**
+     * @param  string $name
+     * @return bool
+     */
+    public function clearLock($name);
+}

src/NinjaMutex/Lock/MemcacheLock.php

@@ -16,13 +16,107 @@
  *
  * @author Kamil Dziedzic <[email protected]>
  */
-class MemcacheLock extends MemcacheLockAbstract
+class MemcacheLock extends LockAbstract implements LockExpirationInterface
 {
+    /**
+     * Maximum expiration time in seconds (30 days)
+     * http://php.net/manual/en/memcache.add.php
+     */
+    const MAX_EXPIRATION = 2592000;
+
+    /**
+     * Memcache connection
+     *
+     * @var Memcache
+     */
+    protected $memcache;
+
+    /**
+     * @var int Expiration time of the lock in seconds
+     */
+    protected $expiration = 0;
+
     /**
      * @param Memcache $memcache
      */
     public function __construct(Memcache $memcache)
     {
-        parent::__construct($memcache);
+        parent::__construct();
+
+        $this->memcache = $memcache;
+    }
+
+    /**
+     * @param int $expiration Expiration time of the lock in seconds. If it's equal to zero (default), the lock will never expire.
+     *                        Max 2592000s (30 days), if greater it will be capped to 2592000 without throwing an error.
+     *                        WARNING: Using value higher than 0 may lead to race conditions. If you set too low expiration time
+     *                        e.g. 30s and critical section will run for 31s another process will gain lock at the same time,
+     *                        leading to unpredicted behaviour. Use with caution.
+     */
+    public function setExpiration($expiration)
+    {
+        if ($expiration > static::MAX_EXPIRATION) {
+            $expiration = static::MAX_EXPIRATION;
+        }
+        $this->expiration = $expiration;
+    }
+
+    /**
+     * Clear lock without releasing it
+     * Do not use this method unless you know what you do
+     *
+     * @param  string $name name of lock
+     * @return bool
+     */
+    public function clearLock($name)
+    {
+        if (!isset($this->locks[$name])) {
+            return false;
+        }
+
+        unset($this->locks[$name]);
+        return true;
+    }
+
+    /**
+     * @param  string $name name of lock
+     * @param  bool   $blocking
+     * @return bool
+     */
+    protected function getLock($name, $blocking)
+    {
+        if (!$this->memcache->add($name, serialize($this->getLockInformation()), 0, $this->expiration)) {
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Release lock
+     *
+     * @param  string $name name of lock
+     * @return bool
+     */
+    public function releaseLock($name)
+    {
+        if (isset($this->locks[$name]) && $this->memcache->delete($name)) {
+            unset($this->locks[$name]);
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Check if lock is locked
+     *
+     * @param  string $name name of lock
+     * @return bool
+     */
+    public function isLocked($name)
+    {
+        return false !== $this->memcache->get($name);
     }
 }

src/NinjaMutex/Lock/MemcachedLock.php

@@ -16,13 +16,108 @@
  *
  * @author Kamil Dziedzic <[email protected]>
  */
-class MemcachedLock extends MemcacheLockAbstract
+class MemcachedLock extends LockAbstract implements LockExpirationInterface
 {
+    /**
+     * Maximum expiration time in seconds (30 days)
+     * http://php.net/manual/en/memcached.add.php
+     */
+    const MAX_EXPIRATION = 2592000;
+
+    /**
+     * Memcache connection
+     *
+     * @var Memcached
+     */
+    protected $memcached;
+
+    /**
+     * @var int Expiration time of the lock in seconds
+     */
+    protected $expiration = 0;
+
     /**
      * @param Memcached $memcached
      */
-    public function __construct(Memcached $memcached)
+    public function __construct($memcached)
+    {
+        parent::__construct();
+
+        $this->memcached = $memcached;
+    }
+
+    /**
+     * @param int $expiration Expiration time of the lock in seconds. If it's equal to zero (default), the lock will never expire.
+     *                        Max 2592000s (30 days), if greater it will be capped to 2592000 without throwing an error.
+     *                        WARNING: Using value higher than 0 may lead to race conditions. If you set too low expiration time
+     *                        e.g. 30s and critical section will run for 31s another process will gain lock at the same time,
+     *                        leading to unpredicted behaviour. Use with caution.
+     */
+    public function setExpiration($expiration)
+    {
+        if ($expiration > static::MAX_EXPIRATION) {
+            $expiration = static::MAX_EXPIRATION;
+        }
+        $this->expiration = $expiration;
+    }
+
+    /**
+     * Clear lock without releasing it
+     * Do not use this method unless you know what you do
+     *
+     * @param  string $name name of lock
+     * @return bool
+     */
+    public function clearLock($name)
     {
-        parent::__construct($memcached);
+        if (!isset($this->locks[$name])) {
+            return false;
+        }
+
+        unset($this->locks[$name]);
+        return true;
+    }
+
+    /**
+     * @param  string $name name of lock
+     * @param  bool   $blocking
+     * @return bool
+     */
+    protected function getLock($name, $blocking)
+    {
+        if (!$this->memcached->add($name, serialize($this->getLockInformation()), $this->expiration)) {
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Release lock
+     *
+     * @param  string $name name of lock
+     * @return bool
+     */
+    public function releaseLock($name)
+    {
+        if (isset($this->locks[$name]) && $this->memcached->delete($name)) {
+            unset($this->locks[$name]);
+
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Check if lock is locked
+     *
+     * @param  string $name name of lock
+     * @return bool
+     */
+    public function isLocked($name)
+    {
+        return false !== $this->memcached->get($name);
     }
 }
+