1/*
2 * Copyright (C) 2010 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 ArgumentDecoder_h
27#define ArgumentDecoder_h
28
29#include "ArgumentCoder.h"
30#include "Attachment.h"
31#include <wtf/PassOwnPtr.h>
32#include <wtf/TypeTraits.h>
33#include <wtf/Vector.h>
34
35namespace CoreIPC {
36
37class DataReference;
38
39class ArgumentDecoder {
40public:
41    static PassOwnPtr<ArgumentDecoder> create(const uint8_t* buffer, size_t bufferSize);
42    virtual ~ArgumentDecoder();
43
44    uint64_t destinationID() const { return m_destinationID; }
45    size_t length() const { return m_bufferEnd - m_buffer; }
46
47    bool isInvalid() const { return m_bufferPos > m_bufferEnd; }
48    void markInvalid() { m_bufferPos = m_bufferEnd + 1; }
49
50    bool decodeFixedLengthData(uint8_t*, size_t, unsigned alignment);
51
52    // The data in the data reference here will only be valid for the lifetime of the ArgumentDecoder object.
53    bool decodeVariableLengthByteArray(DataReference&);
54
55    bool decode(bool&);
56    bool decode(uint8_t&);
57    bool decode(uint16_t&);
58    bool decode(uint32_t&);
59    bool decode(uint64_t&);
60    bool decode(int32_t&);
61    bool decode(int64_t&);
62    bool decode(float&);
63    bool decode(double&);
64
65    template<typename T> bool decodeEnum(T& result)
66    {
67        COMPILE_ASSERT(sizeof(T) <= sizeof(uint64_t), enum_type_must_not_be_larger_than_64_bits);
68
69        uint64_t value;
70        if (!decode(value))
71            return false;
72
73        result = static_cast<T>(value);
74        return true;
75    }
76
77    template<typename T>
78    bool bufferIsLargeEnoughToContain(size_t numElements) const
79    {
80        COMPILE_ASSERT(WTF::IsArithmetic<T>::value, type_must_have_known_encoded_size);
81
82        if (numElements > std::numeric_limits<size_t>::max() / sizeof(T))
83            return false;
84
85        return bufferIsLargeEnoughToContain(__alignof(T), numElements * sizeof(T));
86    }
87
88    // Generic type decode function.
89    template<typename T> bool decode(T& t)
90    {
91        return ArgumentCoder<T>::decode(*this, t);
92    }
93
94    bool removeAttachment(Attachment&);
95
96protected:
97    ArgumentDecoder(const uint8_t* buffer, size_t bufferSize, Vector<Attachment>&);
98
99    void initialize(const uint8_t* buffer, size_t bufferSize);
100
101    bool alignBufferPosition(unsigned alignment, size_t size);
102    bool bufferIsLargeEnoughToContain(unsigned alignment, size_t size) const;
103
104// FIXME: Move m_destinationID to MessageDecoder.
105protected:
106    uint64_t m_destinationID;
107
108private:
109    uint8_t* m_allocatedBase;
110    uint8_t* m_buffer;
111    uint8_t* m_bufferPos;
112    uint8_t* m_bufferEnd;
113
114    Vector<Attachment> m_attachments;
115};
116
117} // namespace CoreIPC
118
119#endif // ArgumentDecoder_h
120