ceph/src/boost/boost/asio/buffered_read_stream.hpp

   1 //
   2 // buffered_read_stream.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_BUFFERED_READ_STREAM_HPP
  12 #define BOOST_ASIO_BUFFERED_READ_STREAM_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19 #include <cstddef>
  20 #include <boost/asio/async_result.hpp>
  21 #include <boost/asio/buffered_read_stream_fwd.hpp>
  22 #include <boost/asio/buffer.hpp>
  23 #include <boost/asio/detail/bind_handler.hpp>
  24 #include <boost/asio/detail/buffer_resize_guard.hpp>
  25 #include <boost/asio/detail/buffered_stream_storage.hpp>
  26 #include <boost/asio/detail/noncopyable.hpp>
  27 #include <boost/asio/detail/type_traits.hpp>
  28 #include <boost/asio/error.hpp>
  29 #include <boost/asio/io_context.hpp>
  30
  31 #include <boost/asio/detail/push_options.hpp>
  32
  33 namespace boost {
  34 namespace asio {
  35
  36 /// Adds buffering to the read-related operations of a stream.
  37 /**
  38  * The buffered_read_stream class template can be used to add buffering to the
  39  * synchronous and asynchronous read operations of a stream.
  40  *
  41  * @par Thread Safety
  42  * @e Distinct @e objects: Safe.@n
  43  * @e Shared @e objects: Unsafe.
  44  *
  45  * @par Concepts:
  46  * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
  47  */
  48 template <typename Stream>
  49 class buffered_read_stream
  50   : private noncopyable
  51 {
  52 public:
  53   /// The type of the next layer.
  54   typedef typename remove_reference<Stream>::type next_layer_type;
  55
  56   /// The type of the lowest layer.
  57   typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
  58
  59   /// The type of the executor associated with the object.
  60   typedef typename lowest_layer_type::executor_type executor_type;
  61
  62 #if defined(GENERATING_DOCUMENTATION)
  63   /// The default buffer size.
  64   static const std::size_t default_buffer_size = implementation_defined;
  65 #else
  66   BOOST_ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
  67 #endif
  68
  69   /// Construct, passing the specified argument to initialise the next layer.
  70   template <typename Arg>
  71   explicit buffered_read_stream(Arg& a)
  72     : next_layer_(a),
  73       storage_(default_buffer_size)
  74   {
  75   }
  76
  77   /// Construct, passing the specified argument to initialise the next layer.
  78   template <typename Arg>
  79   buffered_read_stream(Arg& a, std::size_t buffer_size)
  80     : next_layer_(a),
  81       storage_(buffer_size)
  82   {
  83   }
  84
  85   /// Get a reference to the next layer.
  86   next_layer_type& next_layer()
  87   {
  88     return next_layer_;
  89   }
  90
  91   /// Get a reference to the lowest layer.
  92   lowest_layer_type& lowest_layer()
  93   {
  94     return next_layer_.lowest_layer();
  95   }
  96
  97   /// Get a const reference to the lowest layer.
  98   const lowest_layer_type& lowest_layer() const
  99   {
 100     return next_layer_.lowest_layer();
 101   }
 102
 103   /// Get the executor associated with the object.
 104   executor_type get_executor() BOOST_ASIO_NOEXCEPT
 105   {
 106     return next_layer_.lowest_layer().get_executor();
 107   }
 108
 109 #if !defined(BOOST_ASIO_NO_DEPRECATED)
 110   /// (Deprecated: Use get_executor().) Get the io_context associated with the
 111   /// object.
 112   boost::asio::io_context& get_io_context()
 113   {
 114     return next_layer_.get_io_context();
 115   }
 116
 117   /// (Deprecated: Use get_executor().) Get the io_context associated with the
 118   /// object.
 119   boost::asio::io_context& get_io_service()
 120   {
 121     return next_layer_.get_io_service();
 122   }
 123 #endif // !defined(BOOST_ASIO_NO_DEPRECATED)
 124
 125   /// Close the stream.
 126   void close()
 127   {
 128     next_layer_.close();
 129   }
 130
 131   /// Close the stream.
 132   BOOST_ASIO_SYNC_OP_VOID close(boost::system::error_code& ec)
 133   {
 134     next_layer_.close(ec);
 135     BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
 136   }
 137
 138   /// Write the given data to the stream. Returns the number of bytes written.
 139   /// Throws an exception on failure.
 140   template <typename ConstBufferSequence>
 141   std::size_t write_some(const ConstBufferSequence& buffers)
 142   {
 143     return next_layer_.write_some(buffers);
 144   }
 145
 146   /// Write the given data to the stream. Returns the number of bytes written,
 147   /// or 0 if an error occurred.
 148   template <typename ConstBufferSequence>
 149   std::size_t write_some(const ConstBufferSequence& buffers,
 150       boost::system::error_code& ec)
 151   {
 152     return next_layer_.write_some(buffers, ec);
 153   }
 154
 155   /// Start an asynchronous write. The data being written must be valid for the
 156   /// lifetime of the asynchronous operation.
 157   template <typename ConstBufferSequence, typename WriteHandler>
 158   BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
 159       void (boost::system::error_code, std::size_t))
 160   async_write_some(const ConstBufferSequence& buffers,
 161       BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
 162   {
 163     return next_layer_.async_write_some(buffers,
 164         BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
 165   }
 166
 167   /// Fill the buffer with some data. Returns the number of bytes placed in the
 168   /// buffer as a result of the operation. Throws an exception on failure.
 169   std::size_t fill();
 170
 171   /// Fill the buffer with some data. Returns the number of bytes placed in the
 172   /// buffer as a result of the operation, or 0 if an error occurred.
 173   std::size_t fill(boost::system::error_code& ec);
 174
 175   /// Start an asynchronous fill.
 176   template <typename ReadHandler>
 177   BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
 178       void (boost::system::error_code, std::size_t))
 179   async_fill(BOOST_ASIO_MOVE_ARG(ReadHandler) handler);
 180
 181   /// Read some data from the stream. Returns the number of bytes read. Throws
 182   /// an exception on failure.
 183   template <typename MutableBufferSequence>
 184   std::size_t read_some(const MutableBufferSequence& buffers);
 185
 186   /// Read some data from the stream. Returns the number of bytes read or 0 if
 187   /// an error occurred.
 188   template <typename MutableBufferSequence>
 189   std::size_t read_some(const MutableBufferSequence& buffers,
 190       boost::system::error_code& ec);
 191
 192   /// Start an asynchronous read. The buffer into which the data will be read
 193   /// must be valid for the lifetime of the asynchronous operation.
 194   template <typename MutableBufferSequence, typename ReadHandler>
 195   BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
 196       void (boost::system::error_code, std::size_t))
 197   async_read_some(const MutableBufferSequence& buffers,
 198       BOOST_ASIO_MOVE_ARG(ReadHandler) handler);
 199
 200   /// Peek at the incoming data on the stream. Returns the number of bytes read.
 201   /// Throws an exception on failure.
 202   template <typename MutableBufferSequence>
 203   std::size_t peek(const MutableBufferSequence& buffers);
 204
 205   /// Peek at the incoming data on the stream. Returns the number of bytes read,
 206   /// or 0 if an error occurred.
 207   template <typename MutableBufferSequence>
 208   std::size_t peek(const MutableBufferSequence& buffers,
 209       boost::system::error_code& ec);
 210
 211   /// Determine the amount of data that may be read without blocking.
 212   std::size_t in_avail()
 213   {
 214     return storage_.size();
 215   }
 216
 217   /// Determine the amount of data that may be read without blocking.
 218   std::size_t in_avail(boost::system::error_code& ec)
 219   {
 220     ec = boost::system::error_code();
 221     return storage_.size();
 222   }
 223
 224 private:
 225   /// Copy data out of the internal buffer to the specified target buffer.
 226   /// Returns the number of bytes copied.
 227   template <typename MutableBufferSequence>
 228   std::size_t copy(const MutableBufferSequence& buffers)
 229   {
 230     std::size_t bytes_copied = boost::asio::buffer_copy(
 231         buffers, storage_.data(), storage_.size());
 232     storage_.consume(bytes_copied);
 233     return bytes_copied;
 234   }
 235
 236   /// Copy data from the internal buffer to the specified target buffer, without
 237   /// removing the data from the internal buffer. Returns the number of bytes
 238   /// copied.
 239   template <typename MutableBufferSequence>
 240   std::size_t peek_copy(const MutableBufferSequence& buffers)
 241   {
 242     return boost::asio::buffer_copy(buffers, storage_.data(), storage_.size());
 243   }
 244
 245   /// The next layer.
 246   Stream next_layer_;
 247
 248   // The data in the buffer.
 249   detail::buffered_stream_storage storage_;
 250 };
 251
 252 } // namespace asio
 253 } // namespace boost
 254
 255 #include <boost/asio/detail/pop_options.hpp>
 256
 257 #include <boost/asio/impl/buffered_read_stream.hpp>
 258
 259 #endif // BOOST_ASIO_BUFFERED_READ_STREAM_HPP