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 ShareableResource_h
27#define ShareableResource_h
28
29#include "SharedMemory.h"
30
31#include <wtf/PassRefPtr.h>
32#include <wtf/RefCounted.h>
33#include <wtf/RefPtr.h>
34
35namespace WebCore {
36class SharedBuffer;
37}
38
39namespace WebKit {
40
41class ShareableResource : public RefCounted<ShareableResource> {
42public:
43
44    class Handle {
45        WTF_MAKE_NONCOPYABLE(Handle);
46    public:
47        Handle();
48
49        bool isNull() const { return m_handle.isNull(); }
50        unsigned size() const { return m_size; }
51
52        void encode(CoreIPC::ArgumentEncoder&) const;
53        static bool decode(CoreIPC::ArgumentDecoder&, Handle&);
54
55        PassRefPtr<WebCore::SharedBuffer> tryWrapInSharedBuffer() const;
56
57    private:
58        friend class ShareableResource;
59
60        mutable SharedMemory::Handle m_handle;
61        unsigned m_offset;
62        unsigned m_size;
63    };
64
65    // Create a shareable resource that uses malloced memory.
66    static PassRefPtr<ShareableResource> create(PassRefPtr<SharedMemory>, unsigned offset, unsigned size);
67
68    // Create a shareable resource from a handle.
69    static PassRefPtr<ShareableResource> create(const Handle&);
70
71    // Create a handle.
72    bool createHandle(Handle&);
73
74    ~ShareableResource();
75
76    const char* data() const;
77    unsigned size() const;
78
79private:
80    ShareableResource(PassRefPtr<SharedMemory>, unsigned offset, unsigned size);
81
82    RefPtr<SharedMemory> m_sharedMemory;
83
84    unsigned m_offset;
85    unsigned m_size;
86};
87
88} // namespace WebKit
89
90#endif // ShareableResource_h
91