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/*
*
* 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 "QueueGuard.h"
#include "BrokerInfo.h"
#include "qpid/broker/Queue.h"
#include "qpid/broker/QueuedMessage.h"
#include "qpid/broker/QueueObserver.h"
#include "qpid/log/Statement.h"
#include <boost/bind.hpp>
#include <sstream>
namespace qpid {
namespace ha {
using namespace broker;
using sys::Mutex;
class QueueGuard::QueueObserver : public broker::QueueObserver
{
public:
QueueObserver(QueueGuard& g) : guard(g) {}
void enqueued(const broker::Message& m) { guard.enqueued(m); }
void dequeued(const broker::Message& m) { guard.dequeued(m); }
void acquired(const broker::Message&) {}
void requeued(const broker::Message&) {}
private:
QueueGuard& guard;
};
QueueGuard::QueueGuard(broker::Queue& q, const BrokerInfo& info, const LogPrefix& lp)
: cancelled(false), logPrefix(lp), queue(q)
{
std::ostringstream os;
os << "Guard of " << queue.getName() << " at ";
info.printId(os) << ": ";
logPrefix = os.str();
observer.reset(new QueueObserver(*this));
queue.getObservers().add(observer);
// Set first after adding the observer so we know that the back of the
// queue+1 is (or will be) a guarded position.
QueuePosition front, back;
q.getRange(front, back, broker::REPLICATOR);
first = back + 1;
QPID_LOG(debug, logPrefix << "Guarded: front " << front
<< ", back " << back
<< ", guarded " << first);
}
QueueGuard::~QueueGuard() { cancel(); }
// NOTE: Called with message lock held.
void QueueGuard::enqueued(const Message& m) {
// Delay completion
ReplicationId id = m.getReplicationId();
Mutex::ScopedLock l(lock);
if (cancelled) return; // Don't record enqueues after we are cancelled.
QPID_LOG(trace, logPrefix << "Delayed completion of " << logMessageId(queue, m));
delayed[id] = m.getIngressCompletion();
m.getIngressCompletion()->startCompleter();
}
// NOTE: Called with message lock held.
void QueueGuard::dequeued(const Message& m) {
ReplicationId id = m.getReplicationId();
QPID_LOG(trace, logPrefix << "Dequeued " << logMessageId(queue, m));
Mutex::ScopedLock l(lock);
complete(id, l);
}
void QueueGuard::cancel() {
queue.getObservers().remove(observer);
Mutex::ScopedLock l(lock);
if (cancelled) return;
QPID_LOG(debug, logPrefix << "Cancelled");
cancelled = true;
while (!delayed.empty()) complete(delayed.begin(), l);
}
bool QueueGuard::complete(ReplicationId id) {
Mutex::ScopedLock l(lock);
return complete(id, l);
}
bool QueueGuard::complete(ReplicationId id, Mutex::ScopedLock& l) {
// The same message can be completed twice, by
// ReplicatingSubscription::acknowledged and dequeued. Remove it
// from the map so we only call finishCompleter() once
Delayed::iterator i = delayed.find(id);
if (i != delayed.end()) {
complete(i, l);
return true;
}
return false;
}
void QueueGuard::complete(Delayed::iterator i, Mutex::ScopedLock&) {
QPID_LOG(trace, logPrefix << "Completed " << queue.getName() << " =" << i->first);
i->second->finishCompleter();
delayed.erase(i);
}
}} // namespaces qpid::ha
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