84 lines
1.9 KiB
PHP
84 lines
1.9 KiB
PHP
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<?php
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namespace Friendica\Core\Lock;
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use dba;
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use Friendica\Database\DBM;
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/**
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* Locking driver that stores the locks in the database
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*/
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class DatabaseLockDriver implements ILockDriver
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{
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/**
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* @brief Sets a lock for a given name
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*
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* @param string $key The Name of the lock
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* @param integer $timeout Seconds until we give up
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*
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* @return boolean Was the lock successful?
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*/
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public function acquireLock($key, $timeout = 120)
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{
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$got_lock = false;
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$start = time();
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do {
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dba::lock('locks');
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$lock = dba::selectFirst('locks', ['locked', 'pid'], ['name' => $key]);
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if (DBM::is_result($lock)) {
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if ($lock['locked']) {
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// When the process id isn't used anymore, we can safely claim the lock for us.
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if (!posix_kill($lock['pid'], 0)) {
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$lock['locked'] = false;
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}
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// We want to lock something that was already locked by us? So we got the lock.
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if ($lock['pid'] == getmypid()) {
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$got_lock = true;
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}
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}
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if (!$lock['locked']) {
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dba::update('locks', ['locked' => true, 'pid' => getmypid()], ['name' => $key]);
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$got_lock = true;
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}
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} elseif (!DBM::is_result($lock)) {
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dba::insert('locks', ['name' => $key, 'locked' => true, 'pid' => getmypid()]);
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$got_lock = true;
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}
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dba::unlock();
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if (!$got_lock && ($timeout > 0)) {
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usleep(rand(100000, 2000000));
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}
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} while (!$got_lock && ((time() - $start) < $timeout));
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return $got_lock;
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}
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/**
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* @brief Removes a lock if it was set by us
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*
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* @param string $key Name of the lock
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*
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* @return mixed
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*/
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public function releaseLock($key)
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{
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dba::update('locks', ['locked' => false, 'pid' => 0], ['name' => $key, 'pid' => getmypid()]);
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return;
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}
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/**
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* @brief Removes all lock that were set by us
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*
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* @return void
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*/
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public function releaseAll()
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{
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dba::update('locks', ['locked' => false, 'pid' => 0], ['pid' => getmypid()]);
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}
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}
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