<?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;
}
}
projects / friendica.git / blobdiff