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(PassOwnPtr<PurgeableBuffer>);

    65     

    66     ~SharedBuffer();

    67     

    68 #if PLATFORM(MAC)

    69     NSData *createNSData();

    70     static PassRefPtr<SharedBuffer> wrapNSData(NSData *data);

    71 #endif

    72 #if PLATFORM(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     // Calling this function will force internal segmented buffers

    85     // to be merged into a flat buffer. Use getSomeData() whenever possible

    86     // for better performance.

    87     const Vector<char>& buffer() const;

    88 

    89     bool isEmpty() const { return !size(); }

    90 

    91     void append(const char*, unsigned);

    92     void clear();

    93     const char* platformData() const;

    94     unsigned platformDataSize() const;

    95 

    96     PassRefPtr<SharedBuffer> copy() const;

    97     

    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     void clearPlatformData();

   123     void maybeTransferPlatformData();

   124     bool hasPlatformData() const;

   125     

   126     unsigned m_size;

   127     mutable Vector<char> m_buffer;

   128     mutable Vector<char*> m_segments;

   129     OwnPtr<PurgeableBuffer> m_purgeableBuffer;

   130 #if PLATFORM(CF)

   131     SharedBuffer(CFDataRef);

   132     RetainPtr<CFDataRef> m_cfData;

   133 #endif

   134 };

   135     

   136 }

   137 

   138 #endif // SharedBuffer_h