function DatabaseLockBackend::acquire
Same name in this branch
- 10 core/lib/Drupal/Core/ProxyClass/Lock/DatabaseLockBackend.php \Drupal\Core\ProxyClass\Lock\DatabaseLockBackend::acquire()
Same name in other branches
- 9 core/lib/Drupal/Core/ProxyClass/Lock/DatabaseLockBackend.php \Drupal\Core\ProxyClass\Lock\DatabaseLockBackend::acquire()
- 9 core/lib/Drupal/Core/Lock/DatabaseLockBackend.php \Drupal\Core\Lock\DatabaseLockBackend::acquire()
- 8.9.x core/lib/Drupal/Core/ProxyClass/Lock/DatabaseLockBackend.php \Drupal\Core\ProxyClass\Lock\DatabaseLockBackend::acquire()
- 8.9.x core/lib/Drupal/Core/Lock/DatabaseLockBackend.php \Drupal\Core\Lock\DatabaseLockBackend::acquire()
- 11.x core/lib/Drupal/Core/ProxyClass/Lock/DatabaseLockBackend.php \Drupal\Core\ProxyClass\Lock\DatabaseLockBackend::acquire()
- 11.x core/lib/Drupal/Core/Lock/DatabaseLockBackend.php \Drupal\Core\Lock\DatabaseLockBackend::acquire()
Overrides LockBackendInterface::acquire
File
-
core/
lib/ Drupal/ Core/ Lock/ DatabaseLockBackend.php, line 45
Class
- DatabaseLockBackend
- Defines the database lock backend. This is the default backend in Drupal.
Namespace
Drupal\Core\LockCode
public function acquire($name, $timeout = 30.0) {
$name = $this->normalizeName($name);
// Insure that the timeout is at least 1 ms.
$timeout = max($timeout, 0.001);
$expire = microtime(TRUE) + $timeout;
if (isset($this->locks[$name])) {
// Try to extend the expiration of a lock we already acquired.
$success = (bool) $this->database
->update('semaphore')
->fields([
'expire' => $expire,
])
->condition('name', $name)
->condition('value', $this->getLockId())
->execute();
if (!$success) {
// The lock was broken.
unset($this->locks[$name]);
}
return $success;
}
else {
// Optimistically try to acquire the lock, then retry once if it fails.
// The first time through the loop cannot be a retry.
$retry = FALSE;
// We always want to do this code at least once.
do {
try {
$this->database
->insert('semaphore')
->fields([
'name' => $name,
'value' => $this->getLockId(),
'expire' => $expire,
])
->execute();
// We track all acquired locks in the global variable.
$this->locks[$name] = TRUE;
// We never need to try again.
$retry = FALSE;
} catch (IntegrityConstraintViolationException $e) {
// Suppress the error. If this is our first pass through the loop,
// then $retry is FALSE. In this case, the insert failed because some
// other request acquired the lock but did not release it. We decide
// whether to retry by checking lockMayBeAvailable(). This will clear
// the offending row from the database table in case it has expired.
$retry = $retry ? FALSE : $this->lockMayBeAvailable($name);
} catch (\Exception $e) {
// Create the semaphore table if it does not exist and retry.
if ($this->ensureTableExists()) {
// Retry only once.
$retry = !$retry;
}
else {
throw $e;
}
}
// We only retry in case the first attempt failed, but we then broke
// an expired lock.
} while ($retry);
}
return isset($this->locks[$name]);
}
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