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#ifndef QPID_BROKER_PRIORITYQUEUE_H
#define QPID_BROKER_PRIORITYQUEUE_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 "qpid/broker/MessageDeque.h"
#include "qpid/broker/IndexedDeque.h"
#include "qpid/sys/IntegerTypes.h"
#include <deque>
#include <vector>
namespace qpid {
namespace broker {
/**
* Basic priority queue with a configurable number of recognised
* priority levels. This is implemented as a separate deque per
* priority level.
*
* Browsing is FIFO not priority order. There is a MessageDeque
* for fast browsing.
*/
class PriorityQueue : public Messages
{
public:
PriorityQueue(int levels);
virtual ~PriorityQueue() {}
size_t size();
bool deleted(const QueueCursor&);
void publish(const Message& added);
Message* next(QueueCursor&);
Message* release(const QueueCursor& cursor);
Message* find(const QueueCursor&);
Message* find(const framing::SequenceNumber&, QueueCursor*);
void foreach(Functor);
static uint getPriority(const Message&);
protected:
const int levels;
struct Priority
{
const int start;
int current;
Priority(int s) : start(s), current(start) {}
};
virtual Priority firstLevel();
virtual bool nextLevel(Priority& );
private:
struct MessageHolder
{
Message message;
int priority;
framing::SequenceNumber id;
framing::SequenceNumber getSequence() const;
void setState(MessageState);
MessageState getState() const;
operator Message&();
};
struct MessagePointer
{
MessageHolder* holder;
framing::SequenceNumber id;//used only for padding
framing::SequenceNumber getSequence() const;
void setState(MessageState);
MessageState getState() const;
operator Message&();
};
typedef IndexedDeque<MessageHolder> Deque;
typedef std::vector<Deque> PriorityLevels;
typedef std::vector<framing::SequenceNumber> Counters;
/** Holds pointers to messages (stored in the fifo index) separated by priority.
*/
PriorityLevels messages;
Counters counters;
/** FIFO index of messages for fast browsing and indexing */
IndexedDeque<MessagePointer> fifo;
uint frontLevel;
bool haveFront;
bool cached;
uint getPriorityLevel(const Message&) const;
MessageHolder priorityPadding(qpid::framing::SequenceNumber);
MessagePointer fifoPadding(qpid::framing::SequenceNumber);
};
}} // namespace qpid::broker
#endif /*!QPID_BROKER_PRIORITYQUEUE_H*/
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