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      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 PLATFORM(CF)
     36 #include <wtf/RetainPtr.h>
     37 #endif
     38 
     39 #if PLATFORM(MAC)
     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:
     54     static PassRefPtr<SharedBuffer> create() { return adoptRef(new SharedBuffer); }
     55     static PassRefPtr<SharedBuffer> create(const char* c, int i) { return adoptRef(new SharedBuffer(c, 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(PurgeableBuffer* buffer);
     65 
     66 #if PLATFORM(ANDROID)
     67     virtual
     68 #endif
     69     ~SharedBuffer();
     70 
     71 #if PLATFORM(MAC)
     72     NSData *createNSData();
     73     static PassRefPtr<SharedBuffer> wrapNSData(NSData *data);
     74 #endif
     75 #if PLATFORM(CF)
     76     CFDataRef createCFData();
     77     static PassRefPtr<SharedBuffer> wrapCFData(CFDataRef);
     78 #endif
     79 
     80 #if PLATFORM(ANDROID)
     81     virtual
     82 #endif
     83     // Calling this function will force internal segmented buffers
     84     // to be merged into a flat buffer. Use getSomeData() whenever possible
     85     // for better performance.
     86     const char* data() const;
     87 #if PLATFORM(ANDROID)
     88     virtual
     89 #endif
     90     unsigned size() const;
     91 
     92     // Calling this function will force internal segmented buffers
     93     // to be merged into a flat buffer. Use getSomeData() whenever possible
     94     // for better performance.
     95     const Vector<char>& buffer() const;
     96 
     97     bool isEmpty() const { return !size(); }
     98 
     99     void append(const char*, unsigned);
    100     void clear();
    101     const char* platformData() const;
    102     unsigned platformDataSize() const;
    103 
    104     PassRefPtr<SharedBuffer> copy() const;
    105 
    106     bool hasPurgeableBuffer() const { return m_purgeableBuffer.get(); }
    107 
    108     // Ensure this buffer has no other clients before calling this.
    109     PurgeableBuffer* releasePurgeableBuffer();
    110 
    111     // Return the number of consecutive bytes after "position". "data"
    112     // points to the first byte.
    113     // Return 0 when no more data left.
    114     // When extracting all data with getSomeData(), the caller should
    115     // repeat calling it until it returns 0.
    116     // Usage:
    117     //      const char* segment;
    118     //      unsigned pos = 0;
    119     //      while (unsigned length = sharedBuffer->getSomeData(segment, pos)) {
    120     //          // Use the data. for example: decoder->decode(segment, length);
    121     //          pos += length;
    122     //      }
    123     unsigned getSomeData(const char*& data, unsigned position = 0) const;
    124 
    125 private:
    126     SharedBuffer();
    127     SharedBuffer(const char*, int);
    128     SharedBuffer(const unsigned char*, int);
    129 
    130     void clearPlatformData();
    131     void maybeTransferPlatformData();
    132     bool hasPlatformData() const;
    133 
    134     unsigned m_size;
    135     mutable Vector<char> m_buffer;
    136     mutable Vector<char*> m_segments;
    137     OwnPtr<PurgeableBuffer> m_purgeableBuffer;
    138 #if PLATFORM(CF)
    139     SharedBuffer(CFDataRef);
    140     RetainPtr<CFDataRef> m_cfData;
    141 #endif
    142 };
    143 
    144 }
    145 
    146 #endif // SharedBuffer_h
    147