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/*
* Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "WorkQueue.h"
#include "WorkQueueItem.h"
#include <wtf/Assertions.h>
static const unsigned queueLength = 1024;
static WorkQueueItem* theQueue[queueLength];
static unsigned startOfQueue;
static unsigned endOfQueue;
WorkQueue* WorkQueue::shared()
{
static WorkQueue* sharedInstance = new WorkQueue;
return sharedInstance;
}
WorkQueue::WorkQueue()
: m_frozen(false)
{
}
void WorkQueue::queue(WorkQueueItem* item)
{
ASSERT(endOfQueue < queueLength);
ASSERT(endOfQueue >= startOfQueue);
if (m_frozen) {
delete item;
return;
}
theQueue[endOfQueue++] = item;
}
WorkQueueItem* WorkQueue::dequeue()
{
ASSERT(endOfQueue >= startOfQueue);
if (startOfQueue == endOfQueue)
return 0;
return theQueue[startOfQueue++];
}
unsigned WorkQueue::count()
{
return endOfQueue - startOfQueue;
}
void WorkQueue::clear()
{
for (unsigned i = startOfQueue; i < endOfQueue; ++i) {
delete theQueue[i];
theQueue[i] = 0;
}
startOfQueue = 0;
endOfQueue = 0;
}
bool WorkQueue::processWork()
{
bool startedLoad = false;
while (!startedLoad && count()) {
WorkQueueItem* item = dequeue();
ASSERT(item);
startedLoad = item->invoke();
delete item;
}
// If we're done and we didn't start a load, then we're really done, so return true.
return !startedLoad;
}
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