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 #ifndef SharedBuffer_h
27 #define SharedBuffer_h
28 
29 #include "PlatformString.h"
30 #include <wtf/Forward.h>
31 #include <wtf/OwnPtr.h>
32 #include <wtf/RefCounted.h>
33 #include <wtf/Vector.h>
34 
35 #if USE(CF)
36 #include <wtf/RetainPtr.h>
37 #endif
38 
39 #if PLATFORM(MAC) || (PLATFORM(QT) && USE(QTKIT))
40 #ifdef __OBJC__
41 @class NSData;
42 #else
43 class NSData;
44 #endif
45 
46 #endif
47 
48 namespace WebCore {
49 
50 class PurgeableBuffer;
51 
52 class SharedBuffer : public RefCounted<SharedBuffer> {
53 public:
create()54     static PassRefPtr<SharedBuffer> create() { return adoptRef(new SharedBuffer); }
create(const char * c,int i)55     static PassRefPtr<SharedBuffer> create(const char* c, int i) { return adoptRef(new SharedBuffer(c, i)); }
create(const unsigned char * c,int i)56     static PassRefPtr<SharedBuffer> create(const unsigned char* c, int i) { return adoptRef(new SharedBuffer(c, i)); }
57 
58     static PassRefPtr<SharedBuffer> createWithContentsOfFile(const String& filePath);
59 
60     static PassRefPtr<SharedBuffer> adoptVector(Vector<char>& vector);
61 
62     // The buffer must be in non-purgeable state before adopted to a SharedBuffer.
63     // It will stay that way until released.
64     static PassRefPtr<SharedBuffer> adoptPurgeableBuffer(PassOwnPtr<PurgeableBuffer>);
65 
66     ~SharedBuffer();
67 
68 #if PLATFORM(MAC) || (PLATFORM(QT) && USE(QTKIT))
69     NSData *createNSData();
70     static PassRefPtr<SharedBuffer> wrapNSData(NSData *data);
71 #endif
72 #if USE(CF)
73     CFDataRef createCFData();
74     static PassRefPtr<SharedBuffer> wrapCFData(CFDataRef);
75 #endif
76 
77     // Calling this function will force internal segmented buffers
78     // to be merged into a flat buffer. Use getSomeData() whenever possible
79     // for better performance.
80     const char* data() const;
81 
82     unsigned size() const;
83 
84 
isEmpty()85     bool isEmpty() const { return !size(); }
86 
87     void append(const char*, unsigned);
88     void clear();
89     const char* platformData() const;
90     unsigned platformDataSize() const;
91 
92 #if HAVE(CFNETWORK_DATA_ARRAY_CALLBACK)
93     void append(CFDataRef);
94 #endif
95 
96     PassRefPtr<SharedBuffer> copy() const;
97 
hasPurgeableBuffer()98     bool hasPurgeableBuffer() const { return m_purgeableBuffer.get(); }
99 
100     // Ensure this buffer has no other clients before calling this.
101     PassOwnPtr<PurgeableBuffer> releasePurgeableBuffer();
102 
103     // Return the number of consecutive bytes after "position". "data"
104     // points to the first byte.
105     // Return 0 when no more data left.
106     // When extracting all data with getSomeData(), the caller should
107     // repeat calling it until it returns 0.
108     // Usage:
109     //      const char* segment;
110     //      unsigned pos = 0;
111     //      while (unsigned length = sharedBuffer->getSomeData(segment, pos)) {
112     //          // Use the data. for example: decoder->decode(segment, length);
113     //          pos += length;
114     //      }
115     unsigned getSomeData(const char*& data, unsigned position = 0) const;
116 
117 private:
118     SharedBuffer();
119     SharedBuffer(const char*, int);
120     SharedBuffer(const unsigned char*, int);
121 
122     // Calling this function will force internal segmented buffers
123     // to be merged into a flat buffer. Use getSomeData() whenever possible
124     // for better performance.
125     // As well, be aware that this method does *not* return any purgeable
126     // memory, which can be a source of bugs.
127     const Vector<char>& buffer() const;
128 
129     void clearPlatformData();
130     void maybeTransferPlatformData();
131     bool hasPlatformData() const;
132 
133     unsigned m_size;
134     mutable Vector<char> m_buffer;
135     mutable Vector<char*> m_segments;
136     OwnPtr<PurgeableBuffer> m_purgeableBuffer;
137 #if HAVE(CFNETWORK_DATA_ARRAY_CALLBACK)
138     mutable Vector<RetainPtr<CFDataRef> > m_dataArray;
139     void copyDataArrayAndClear(char *destination, unsigned bytesToCopy) const;
140 #endif
141 #if USE(CF)
142     SharedBuffer(CFDataRef);
143     RetainPtr<CFDataRef> m_cfData;
144 #endif
145 };
146 
147 }
148 
149 #endif // SharedBuffer_h
150