1/*
2 * Copyright (C) 2012 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef BlockingResponseMap_h
27#define BlockingResponseMap_h
28
29#include <wtf/HashMap.h>
30#include <wtf/OwnPtr.h>
31#include <wtf/PassOwnPtr.h>
32#include <wtf/ThreadingPrimitives.h>
33
34template<typename T>
35class BlockingResponseMap {
36WTF_MAKE_NONCOPYABLE(BlockingResponseMap);
37public:
38    BlockingResponseMap() : m_canceled(false) { }
39    ~BlockingResponseMap() { ASSERT(m_responses.isEmpty()); }
40
41    PassOwnPtr<T> waitForResponse(uint64_t requestID)
42    {
43        while (true) {
44            MutexLocker locker(m_mutex);
45
46            if (m_canceled)
47                return nullptr;
48
49            if (OwnPtr<T> response = m_responses.take(requestID))
50                return response.release();
51
52            m_condition.wait(m_mutex);
53        }
54
55        return nullptr;
56    }
57
58    void didReceiveResponse(uint64_t requestID, PassOwnPtr<T> response)
59    {
60        MutexLocker locker(m_mutex);
61        ASSERT(!m_responses.contains(requestID));
62
63        m_responses.set(requestID, response);
64        // FIXME: Waking up all threads is quite inefficient.
65        m_condition.broadcast();
66    }
67
68    void cancel()
69    {
70        m_canceled = true;
71
72        // FIXME: Waking up all threads is quite inefficient.
73        m_condition.broadcast();
74    }
75
76private:
77    Mutex m_mutex;
78    ThreadCondition m_condition;
79
80    HashMap<uint64_t, OwnPtr<T>> m_responses;
81    bool m_canceled;
82};
83
84#endif // BlockingResponseMap_h
85