1/*
2 * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
3 * Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#ifndef SharedBuffer_h
28#define SharedBuffer_h
29
30#include "platform/PlatformExport.h"
31#include "platform/PurgeableVector.h"
32#include "third_party/skia/include/core/SkData.h"
33#include "wtf/ArrayBuffer.h"
34#include "wtf/Forward.h"
35#include "wtf/OwnPtr.h"
36#include "wtf/RefCounted.h"
37#include "wtf/text/WTFString.h"
38
39namespace blink {
40
41class PLATFORM_EXPORT SharedBuffer : public RefCounted<SharedBuffer> {
42public:
43    static PassRefPtr<SharedBuffer> create() { return adoptRef(new SharedBuffer); }
44    static PassRefPtr<SharedBuffer> create(size_t size) { return adoptRef(new SharedBuffer(size)); }
45    static PassRefPtr<SharedBuffer> create(const char* c, int i) { return adoptRef(new SharedBuffer(c, i)); }
46    static PassRefPtr<SharedBuffer> create(const unsigned char* c, int i) { return adoptRef(new SharedBuffer(c, i)); }
47
48    static PassRefPtr<SharedBuffer> createPurgeable(const char* c, int i) { return adoptRef(new SharedBuffer(c, i, PurgeableVector::Purgeable)); }
49
50    static PassRefPtr<SharedBuffer> adoptVector(Vector<char>&);
51
52    ~SharedBuffer();
53
54    // Calling this function will force internal segmented buffers to be merged
55    // into a flat buffer. Use getSomeData() whenever possible for better
56    // performance.
57    const char* data() const;
58
59    unsigned size() const;
60
61    bool isEmpty() const { return !size(); }
62
63    void append(PassRefPtr<SharedBuffer>);
64    void append(const char*, unsigned);
65    void append(const Vector<char>&);
66
67    void clear();
68
69    PassRefPtr<SharedBuffer> copy() const;
70
71    // Return the number of consecutive bytes after "position". "data"
72    // points to the first byte.
73    // Return 0 when no more data left.
74    // When extracting all data with getSomeData(), the caller should
75    // repeat calling it until it returns 0.
76    // Usage:
77    //      const char* segment;
78    //      unsigned pos = 0;
79    //      while (unsigned length = sharedBuffer->getSomeData(segment, pos)) {
80    //          // Use the data. for example: decoder->decode(segment, length);
81    //          pos += length;
82    //      }
83    unsigned getSomeData(const char*& data, unsigned position = 0) const;
84
85    // Creates an ArrayBuffer and copies this SharedBuffer's contents to that
86    // ArrayBuffer without merging segmented buffers into a flat buffer. If
87    // allocation of an ArrayBuffer fails, returns 0.
88    PassRefPtr<ArrayBuffer> getAsArrayBuffer() const;
89
90    // Creates an SkData and copies this SharedBuffer's contents to that
91    // SkData without merging segmented buffers into a flat buffer.
92    PassRefPtr<SkData> getAsSkData() const;
93
94    // See PurgeableVector::lock().
95    bool lock();
96
97    // WARNING: Calling unlock() on a SharedBuffer that wasn't created with the
98    // purgeability option does an extra memcpy(). Please use
99    // SharedBuffer::createPurgeable() if you intend to call unlock().
100    void unlock();
101
102    bool isLocked() const;
103
104private:
105    SharedBuffer();
106    explicit SharedBuffer(size_t);
107    SharedBuffer(const char*, int);
108    SharedBuffer(const char*, int, PurgeableVector::PurgeableOption);
109    SharedBuffer(const unsigned char*, int);
110
111    // See SharedBuffer::data().
112    void mergeSegmentsIntoBuffer() const;
113
114    unsigned m_size;
115    mutable PurgeableVector m_buffer;
116    mutable Vector<char*> m_segments;
117};
118
119} // namespace blink
120
121#endif // SharedBuffer_h
122