X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FUtil%2FLock.php;h=eba264ad932d6ba6357c5fd566cafbc8c7ff8a30;hb=1e9bff88bc05fce154edee9f047e7d8922184140;hp=03e8545adfdaadc20866268ce7b8c1156648955c;hpb=32f61016d368401890443efc861fff0032ac6c42;p=friendica.git

diff --git a/src/Util/Lock.php b/src/Util/Lock.php
index 03e8545adf..eba264ad93 100644
--- a/src/Util/Lock.php
+++ b/src/Util/Lock.php
@@ -1,62 +1,211 @@
 <?php
-
+/**
+ * @file src/Util/Lock.php
+ */
 namespace Friendica\Util;
 
 /**
  * @file src/Util/Lock.php
  * @brief Functions for preventing parallel execution of functions
- *
  */
 
+use Friendica\Core\Config;
+use Friendica\Database\DBM;
+use Memcache;
 use dba;
-use dbm;
+
+require_once 'include/dba.php';
 
 /**
  * @brief This class contain Functions for preventing parallel execution of functions
  */
-class Lock {
+class Lock
+{
+	private static $semaphore = [];
+
+	/**
+	 * @brief Check for memcache and open a connection if configured
+	 *
+	 * @return object|boolean The memcache object - or "false" if not successful
+	 */
+	private static function connectMemcache()
+	{
+		if (!function_exists('memcache_connect')) {
+			return false;
+		}
+
+		if (!Config::get('system', 'memcache')) {
+			return false;
+		}
 
+		$memcache_host = Config::get('system', 'memcache_host', '127.0.0.1');
+		$memcache_port = Config::get('system', 'memcache_port', 11211);
 
-// Provide some ability to lock a PHP function so that multiple processes
-// can't run the function concurrently
+		$memcache = new Memcache;
 
-	public static function set($fn_name, $wait_sec = 2, $timeout = 30) {
-		if ($wait_sec == 0) {
-			$wait_sec = 2;
+		if (!$memcache->connect($memcache_host, $memcache_port)) {
+			return false;
 		}
 
+		return $memcache;
+	}
+
+	/**
+	 * @brief Creates a semaphore key
+	 *
+	 * @param string $fn_name Name of the lock
+	 *
+	 * @return ressource the semaphore key
+	 */
+	private static function semaphoreKey($fn_name)
+	{
+		$temp = get_temppath();
+
+		$file = $temp.'/'.$fn_name.'.sem';
+
+		if (!file_exists($file)) {
+			file_put_contents($file, $fn_name);
+		}
+
+		return ftok($file, 'f');
+	}
+
+	/**
+	 * @brief Sets a lock for a given name
+	 *
+	 * @param string  $fn_name Name of the lock
+	 * @param integer $timeout Seconds until we give up
+	 *
+	 * @return boolean Was the lock successful?
+	 */
+	public static function set($fn_name, $timeout = 120)
+	{
 		$got_lock = false;
 		$start = time();
 
-		do {
-			dba:p("LOCK TABLE `locks` WRITE");
-			$lock = dba::select('locks', array('locked'), array('name' => $fn_name), array('limit' => 1));
+		// The second parameter for "sem_acquire" doesn't exist before 5.6.1
+		if (function_exists('sem_get') && version_compare(PHP_VERSION, '5.6.1', '>=')) {
+			self::$semaphore[$fn_name] = sem_get(self::semaphoreKey($fn_name));
+			if (self::$semaphore[$fn_name]) {
+				return sem_acquire(self::$semaphore[$fn_name], ($timeout == 0));
+			}
+		}
 
-			if ((dbm::is_result($lock)) AND !$lock['locked']) {
-				dba::update('locks', array('locked' => true), array('name' => $fn_name));
-				$got_lock = true;
-			} elseif (!dbm::is_result($lock)) {
-				dbm::insert('locks', array('name' => $fn_name, 'locked' => true));
+		$memcache = self::connectMemcache();
+		if (is_object($memcache)) {
+			$cachekey = get_app()->get_hostname().";lock:".$fn_name;
+
+			do {
+				// We only lock to be sure that nothing happens at exactly the same time
+				dba::lock('locks');
+				$lock = $memcache->get($cachekey);
+
+				if (!is_bool($lock)) {
+					$pid = (int)$lock;
+
+					// When the process id isn't used anymore, we can safely claim the lock for us.
+					// Or we do want to lock something that was already locked by us.
+					if (!posix_kill($pid, 0) || ($pid == getmypid())) {
+						$lock = false;
+					}
+				}
+				if (is_bool($lock)) {
+					$memcache->set($cachekey, getmypid(), MEMCACHE_COMPRESSED, 300);
+					$got_lock = true;
+				}
+
+				dba::unlock();
+
+				if (!$got_lock && ($timeout > 0)) {
+					usleep(rand(10000, 200000));
+				}
+			} while (!$got_lock && ((time() - $start) < $timeout));
+
+			return $got_lock;
+		}
+
+		do {
+			dba::lock('locks');
+			$lock = dba::selectFirst('locks', ['locked', 'pid'], ['name' => $fn_name]);
+
+			if (DBM::is_result($lock)) {
+				if ($lock['locked']) {
+					// When the process id isn't used anymore, we can safely claim the lock for us.
+					if (!posix_kill($lock['pid'], 0)) {
+						$lock['locked'] = false;
+					}
+					// We want to lock something that was already locked by us? So we got the lock.
+					if ($lock['pid'] == getmypid()) {
+						$got_lock = true;
+					}
+				}
+				if (!$lock['locked']) {
+					dba::update('locks', ['locked' => true, 'pid' => getmypid()], ['name' => $fn_name]);
+					$got_lock = true;
+				}
+			} elseif (!DBM::is_result($lock)) {
+				dba::insert('locks', ['name' => $fn_name, 'locked' => true, 'pid' => getmypid()]);
 				$got_lock = true;
 			}
 
-			dbm::p("UNLOCK TABLES");
+			dba::unlock();
 
-			if (!$got_lock) {
-				sleep($wait_sec);
+			if (!$got_lock && ($timeout > 0)) {
+				usleep(rand(100000, 2000000));
 			}
-		} while (!$got_lock AND ((time() - $start) < $timeout));
-
-		logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock . ' time = ' . (time() - $start), LOGGER_DEBUG);
+		} while (!$got_lock && ((time() - $start) < $timeout));
 
 		return $got_lock;
 	}
 
-	public static function remove($fn_name) {
-		dba::update('locks', array('locked' => false), array('name' => $fn_name));
+	/**
+	 * @brief Removes a lock if it was set by us
+	 *
+	 * @param string $fn_name Name of the lock
+	 * @return mixed
+	 */
+	public static function remove($fn_name)
+	{
+		if (function_exists('sem_get') && version_compare(PHP_VERSION, '5.6.1', '>=')) {
+			if (empty(self::$semaphore[$fn_name])) {
+				return false;
+			} else {
+				$success = @sem_release(self::$semaphore[$fn_name]);
+				unset(self::$semaphore[$fn_name]);
+				return $success;
+			}
+		}
+
+		$memcache = self::connectMemcache();
+		if (is_object($memcache)) {
+			$cachekey = get_app()->get_hostname().";lock:".$fn_name;
+			$lock = $memcache->get($cachekey);
+
+			if (!is_bool($lock)) {
+				if ((int)$lock == getmypid()) {
+					$memcache->delete($cachekey);
+				}
+			}
+			return;
+		}
+
+		dba::update('locks', ['locked' => false, 'pid' => 0], ['name' => $fn_name, 'pid' => getmypid()]);
+		return;
+	}
 
-		logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
+	/**
+	 * @brief Removes all lock that were set by us
+	 * @return void
+	 */
+	public static function removeAll()
+	{
+		$memcache = self::connectMemcache();
+		if (is_object($memcache)) {
+			// We cannot delete all cache entries, but this doesn't matter with memcache
+			return;
+		}
 
+		dba::update('locks', ['locked' => false, 'pid' => 0], ['pid' => getmypid()]);
 		return;
 	}
 }