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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 "qpid/broker/MessageDeque.h"
#include "qpid/broker/QueuedMessage.h"
#include "qpid/log/Statement.h"
namespace qpid {
namespace broker {
MessageDeque::MessageDeque() : available(0), head(0) {}
size_t MessageDeque::index(const framing::SequenceNumber& position)
{
//assuming a monotonic sequence, with no messages removed except
//from the ends of the deque, we can use the position to determin
//an index into the deque
if (messages.empty() || position < messages.front().position) return 0;
return position - messages.front().position;
}
bool MessageDeque::deleted(const QueuedMessage& m)
{
size_t i = index(m.position);
if (i < messages.size()) {
messages[i].status = QueuedMessage::DELETED;
clean();
return true;
} else {
return false;
}
}
size_t MessageDeque::size()
{
return available;
}
void MessageDeque::release(const QueuedMessage& message)
{
size_t i = index(message.position);
if (i < messages.size()) {
QueuedMessage& m = messages[i];
if (m.status == QueuedMessage::ACQUIRED) {
if (head > i) head = i;
m.status = QueuedMessage::AVAILABLE;
++available;
}
} else {
QPID_LOG(error, "Failed to release message at " << message.position << " " << message.payload->getFrames().getContent() << "; no such message (index=" << i << ", size=" << messages.size() << ")");
}
}
bool MessageDeque::acquire(const framing::SequenceNumber& position, QueuedMessage& message)
{
if (position < messages.front().position) return false;
size_t i = index(position);
if (i < messages.size()) {
QueuedMessage& temp = messages[i];
if (temp.status == QueuedMessage::AVAILABLE) {
temp.status = QueuedMessage::ACQUIRED;
--available;
message = temp;
return true;
}
}
return false;
}
bool MessageDeque::find(const framing::SequenceNumber& position, QueuedMessage& message)
{
size_t i = index(position);
if (i < messages.size()) {
message = messages[i];
return true;
} else {
return false;
}
}
bool MessageDeque::browse(const framing::SequenceNumber& position, QueuedMessage& message, bool unacquired)
{
//get first message that is greater than position
size_t i = index(position + 1);
while (i < messages.size()) {
QueuedMessage& m = messages[i++];
if (m.status == QueuedMessage::AVAILABLE || (!unacquired && m.status == QueuedMessage::ACQUIRED)) {
message = m;
return true;
}
}
return false;
}
bool MessageDeque::consume(QueuedMessage& message)
{
while (head < messages.size()) {
QueuedMessage& i = messages[head++];
if (i.status == QueuedMessage::AVAILABLE) {
i.status = QueuedMessage::ACQUIRED;
--available;
message = i;
return true;
}
}
return false;
}
bool MessageDeque::push(const QueuedMessage& added, QueuedMessage& /*not needed*/)
{
//add padding to prevent gaps in sequence, which break the index
//calculation (needed for queue replication)
while (messages.size() && (added.position - messages.back().position) > 1) {
QueuedMessage dummy;
dummy.position = messages.back().position + 1;
dummy.status = QueuedMessage::DELETED;
messages.push_back(dummy);
QPID_LOG(debug, "Adding padding at " << dummy.position << ", between " << messages.back().position << " and " << added.position);
}
messages.push_back(added);
messages.back().status = QueuedMessage::AVAILABLE;
if (head >= messages.size()) head = messages.size() - 1;
++available;
return false;//adding a message never causes one to be removed for deque
}
void MessageDeque::clean()
{
while (messages.size() && messages.front().status == QueuedMessage::DELETED) {
messages.pop_front();
if (head) --head;
}
}
void MessageDeque::foreach(Functor f)
{
for (Deque::iterator i = messages.begin(); i != messages.end(); ++i) {
if (i->status == QueuedMessage::AVAILABLE) {
f(*i);
}
}
}
void MessageDeque::removeIf(Predicate p)
{
for (Deque::iterator i = messages.begin(); i != messages.end(); ++i) {
if (i->status == QueuedMessage::AVAILABLE && p(*i)) {
//Use special status for this as messages are not yet
//dequeued, but should not be considered on the queue
//either (used for purging and moving)
i->status = QueuedMessage::REMOVED;
--available;
}
}
clean();
}
}} // namespace qpid::broker
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