2 * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 #include "WorkQueue.h"
33 #include "WorkQueueItemQt.h"
35 #include "WorkQueueItem.h"
37 #include <wtf/Assertions.h>
39 static const unsigned queueLength = 1024;
41 static WorkQueueItem* theQueue[queueLength];
42 static unsigned startOfQueue;
43 static unsigned endOfQueue;
45 WorkQueue* WorkQueue::shared()
47 static WorkQueue* sharedInstance = new WorkQueue;
48 return sharedInstance;
51 WorkQueue::WorkQueue()
56 void WorkQueue::queue(WorkQueueItem* item)
58 ASSERT(endOfQueue < queueLength);
59 ASSERT(endOfQueue >= startOfQueue);
66 theQueue[endOfQueue++] = item;
69 WorkQueueItem* WorkQueue::dequeue()
71 ASSERT(endOfQueue >= startOfQueue);
73 if (startOfQueue == endOfQueue)
76 return theQueue[startOfQueue++];
79 unsigned WorkQueue::count()
81 return endOfQueue - startOfQueue;
84 void WorkQueue::clear()
86 for (unsigned i = startOfQueue; i < endOfQueue; ++i) {
95 bool WorkQueue::processWork()
97 bool startedLoad = false;
99 while (!startedLoad && count()) {
100 WorkQueueItem* item = dequeue();
102 startedLoad = item->invoke();
106 // If we're done and we didn't start a load, then we're really done, so return true.