public function lockAcquire($name, $timeout = 30.0)
{
$client = Redis_Client::getClient();
$key = $this->getKey($name);
$id = $this->getLockId();
// Insure that the timeout is at least 1 second, we cannot do otherwise with
// Redis, this is a minor change to the function signature, but in real life
// nobody will notice with so short duration.
$timeout = ceil(max($timeout, 1));
// If we already have the lock, check for his owner and attempt a new EXPIRE
// command on it.
if (isset($this->_locks[$name])) {
// Create a new transaction, for atomicity.
$client->watch($key);
// Global tells us we are the owner, but in real life it could have expired
// and another process could have taken it, check that.
if ($client->get($key) != $id) {
$client->unwatch($key);
unset($this->_locks[$name]);
return FALSE;
}
switch (Redis_Client_Predis::getPredisVersionMajor()) {
case 0:
$replies = $client->pipeline(function ($pipe) use($key, $timeout, $id) {
$pipe->multi();
$pipe->setex($key, $timeout, $id);
$pipe->exec();
});
break;
default:
$replies = $client->transaction(function ($pipe) use($key, $timeout, $id) {
$pipe->setex($key, $timeout, $id);
});
break;
}
$execReply = array_pop($replies);
if (FALSE === $execReply[0]) {
unset($this->_locks[$name]);
return FALSE;
}
return TRUE;
} else {
$client->watch($key);
$owner = $client->get($key);
if (!empty($owner) && $owner != $id) {
$client->unwatch();
unset($this->_locks[$name]);
return FALSE;
}
$replies = $client->pipeline(function ($pipe) use($key, $timeout, $id) {
$pipe->multi();
$pipe->setex($key, $timeout, $id);
$pipe->exec();
});
$execReply = array_pop($replies);
// If another client modified the $key value, transaction will be discarded
// $result will be set to FALSE. This means atomicity have been broken and
// the other client took the lock instead of us.
// EXPIRE and SETEX won't return something here, EXEC return is index 0
// This was determined debugging, seems to be Predis specific.
if (FALSE === $execReply[0]) {
return FALSE;
}
// Register the lock and return.
return $this->_locks[$name] = TRUE;
}
return FALSE;
}
