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/Condition.h>
30#include <wtf/HashMap.h>
31#include <wtf/Lock.h>
32#include <wtf/Noncopyable.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 std::unique_ptr<T> waitForResponse(uint64_t requestID)
42 {
43 while (true) {
44 std::unique_lock<Lock> lock(m_mutex);
45
46 if (m_canceled)
47 return nullptr;
48
49 if (std::unique_ptr<T> response = m_responses.take(requestID))
50 return response;
51
52 m_condition.wait(lock);
53 }
54
55 return nullptr;
56 }
57
58 void didReceiveResponse(uint64_t requestID, std::unique_ptr<T> response)
59 {
60 std::lock_guard<Lock> lock(m_mutex);
61 ASSERT(!m_responses.contains(requestID));
62
63 m_responses.set(requestID, WTFMove(response));
64
65 // FIXME: Could get a slight speed-up from using notifyOne().
66 m_condition.notifyAll();
67 }
68
69 void cancel()
70 {
71 m_canceled = true;
72
73 // FIXME: Could get a slight speed-up from using notifyOne().
74 m_condition.notifyAll();
75 }
76
77private:
78 Lock m_mutex;
79 Condition m_condition;
80
81 HashMap<uint64_t, std::unique_ptr<T>> m_responses;
82 bool m_canceled;
83};
84
85#endif // BlockingResponseMap_h
86