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#ifndef QPID_HA_QUEUEGUARD_H
#define QPID_HA_QUEUEGUARD_H
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
#include "types.h"
#include "hash.h"
#include "LogPrefix.h"
#include "qpid/types/Uuid.h"
#include "qpid/sys/Mutex.h"
#include "qpid/sys/unordered_map.h"
#include <boost/shared_ptr.hpp>
#include <boost/intrusive_ptr.hpp>
#include <deque>
#include <set>
namespace qpid {
namespace broker {
class Queue;
struct QueuedMessage;
class Message;
class AsyncCompletion;
}
namespace ha {
class BrokerInfo;
class ReplicatingSubscription;
/**
* A queue guard is a QueueObserver that delays completion of new messages
* arriving on a queue. It works as part of a ReplicatingSubscription to ensure
* messages are not acknowledged till they have been replicated.
*
* The guard can be created before the ReplicatingSubscription to protect
* messages arriving before the creation of the subscription.
*
* THREAD SAFE: Concurrent calls:
* - enqueued() via QueueObserver in arbitrary connection threads.
* - cancel(), complete() from ReplicatingSubscription in subscription thread.
*
*/
class QueueGuard {
public:
QueueGuard(broker::Queue& q, const BrokerInfo&, const LogPrefix&);
~QueueGuard();
/** QueueObserver override. Delay completion of the message.
* NOTE: Called under the queues message lock.
*/
void enqueued(const broker::Message&);
/** QueueObserver override: Complete a delayed message.
* NOTE: Called under the queues message lock.
*/
void dequeued(const broker::Message&);
/** Complete a delayed message.
*@return true if the ID was delayed
*/
bool complete(ReplicationId);
/** Complete all delayed messages. */
void cancel();
/** Return the first known guarded position on the queue. It is possible
* that the guard has seen a few messages before this point.
*/
QueuePosition getFirst() const { return first; } // Thread safe: Immutable.
private:
class QueueObserver;
typedef qpid::sys::unordered_map<ReplicationId,
boost::intrusive_ptr<broker::AsyncCompletion>,
Hasher<ReplicationId> > Delayed;
bool complete(ReplicationId, sys::Mutex::ScopedLock &);
void complete(Delayed::iterator, sys::Mutex::ScopedLock &);
sys::Mutex lock;
QueuePosition first;
bool cancelled;
LogPrefix2 logPrefix;
broker::Queue& queue;
Delayed delayed;
boost::shared_ptr<QueueObserver> observer;
};
}} // namespace qpid::ha
#endif /*!QPID_HA_QUEUEGUARD_H*/
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