components/pairing/message_buffer.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_PAIRING_MESSAGE_BUFFER_H_
   6 #define COMPONENTS_PAIRING_MESSAGE_BUFFER_H_
   7
   8 #include <deque>
   9
  10 #include "base/logging.h"
  11 #include "base/macros.h"
  12 #include "base/memory/ref_counted.h"
  13
  14 namespace net {
  15 class IOBuffer;
  16 }
  17
  18 namespace pairing_chromeos {
  19
  20 // A MessageBuffer is a simple wrapper around an ordered set of buffers received
  21 // from a socket.  It keeps track of the amount of unread data, and allows data
  22 // to be retreived that was split across buffers in a single chunk.
  23 class MessageBuffer {
  24  public:
  25   MessageBuffer();
  26   ~MessageBuffer();
  27
  28   // Returns the number of bytes currently received, but not yet read.
  29   int AvailableBytes();
  30
  31   // Read |size| bytes into |buffer|.  |size| must be smaller than or equal to
  32   // the current number of available bytes.
  33   void ReadBytes(char* buffer, int size);
  34
  35   // Add the data from an IOBuffer.  A reference to the IOBuffer will be
  36   // maintained until it is drained.
  37   void AddIOBuffer(scoped_refptr<net::IOBuffer> io_buffer, int size);
  38
  39  private:
  40   // Offset of the next byte to be read from the current IOBuffer.
  41   int buffer_offset_;
  42   // Total number of bytes in IOBuffers in |pending_data_|, including bytes that
  43   // have already been read.
  44   int total_buffer_size_;
  45   std::deque<std::pair<scoped_refptr<net::IOBuffer>, int> > pending_data_;
  46
  47   DISALLOW_COPY_AND_ASSIGN(MessageBuffer);
  48 };
  49
  50 }  // namespace pairing_chromeos
  51
  52 #endif  // COMPONENTS_PAIRING_MESSAGE_BUFFER_H_