1/*
2 * Copyright (C) 2011, 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 ConnectionStack_h
27#define ConnectionStack_h
28
29#include <wtf/Vector.h>
30
31namespace IPC {
32    class Connection;
33}
34
35namespace WebKit {
36
37class ConnectionStack {
38public:
39    static ConnectionStack& shared();
40
41    IPC::Connection* current()
42    {
43        return m_connectionStack.last();
44    }
45
46    class CurrentConnectionPusher {
47    public:
48        CurrentConnectionPusher(ConnectionStack& connectionStack, IPC::Connection* connection)
49            : m_connectionStack(connectionStack)
50#if !ASSERT_DISABLED
51            , m_connection(connection)
52#endif
53        {
54            m_connectionStack.m_connectionStack.append(connection);
55        }
56
57        ~CurrentConnectionPusher()
58        {
59            ASSERT(m_connectionStack.current() == m_connection);
60            m_connectionStack.m_connectionStack.removeLast();
61        }
62
63    private:
64        ConnectionStack& m_connectionStack;
65#if !ASSERT_DISABLED
66        IPC::Connection* m_connection;
67#endif
68    };
69
70private:
71    // It's OK for these to be weak pointers because we only push object on the stack
72    // from within didReceiveMessage and didReceiveSyncMessage and the Connection objects are
73    // already ref'd for the duration of those functions.
74    Vector<IPC::Connection*, 4> m_connectionStack;
75};
76
77} // namespace WebKit
78
79#endif // ConnectionStack_h
80