Line data    Source code

       1              : //
       2              : // Copyright (c) 2025 Vinnie Falco (vinnie dot falco at gmail dot com)
       3              : //
       4              : // Distributed under the Boost Software License, Version 1.0. (See accompanying
       5              : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
       6              : //
       7              : // Official repository: https://github.com/cppalliance/capy
       8              : //
       9              : 
      10              : #ifndef BOOST_CAPY_WRITE_HPP
      11              : #define BOOST_CAPY_WRITE_HPP
      12              : 
      13              : #include <boost/capy/detail/config.hpp>
      14              : #include <boost/capy/io_result.hpp>
      15              : #include <boost/capy/task.hpp>
      16              : #include <boost/capy/buffers.hpp>
      17              : #include <boost/capy/buffers/consuming_buffers.hpp>
      18              : #include <boost/capy/concept/write_stream.hpp>
      19              : #include <system_error>
      20              : 
      21              : #include <cstddef>
      22              : 
      23              : namespace boost {
      24              : namespace capy {
      25              : 
      26              : /** Asynchronously write the entire buffer sequence.
      27              : 
      28              :     Writes data to the stream by calling `write_some` repeatedly
      29              :     until the entire buffer sequence is written or an error occurs.
      30              : 
      31              :     @li The operation completes when:
      32              :     @li The entire buffer sequence has been written
      33              :     @li An error occurs
      34              :     @li The operation is cancelled
      35              : 
      36              :     @par Cancellation
      37              :     Supports cancellation via `stop_token` propagated through the
      38              :     IoAwaitable protocol. When cancelled, returns with `cond::canceled`.
      39              : 
      40              :     @param stream The stream to write to. The caller retains ownership.
      41              :     @param buffers The buffer sequence to write. The caller retains
      42              :         ownership and must ensure validity until the operation completes.
      43              : 
      44              :     @return An awaitable yielding `(error_code, std::size_t)`.
      45              :         On success, `n` equals `buffer_size(buffers)`. On error,
      46              :         `n` is the number of bytes written before the error. Compare
      47              :         error codes to conditions:
      48              :         @li `cond::canceled` - Operation was cancelled
      49              :         @li `std::errc::broken_pipe` - Peer closed connection
      50              : 
      51              :     @par Example
      52              : 
      53              :     @code
      54              :     task<> send_response( WriteStream auto& stream, std::string_view body )
      55              :     {
      56              :         auto [ec, n] = co_await write( stream, make_buffer( body ) );
      57              :         if( ec.failed() )
      58              :             detail::throw_system_error( ec );
      59              :         // All bytes written successfully
      60              :     }
      61              :     @endcode
      62              : 
      63              :     @see write_some, WriteStream, ConstBufferSequence
      64              : */
      65              : auto
      66           44 : write(
      67              :     WriteStream auto& stream,
      68              :     ConstBufferSequence auto const& buffers) ->
      69              :         task<io_result<std::size_t>>
      70              : {
      71              :     consuming_buffers consuming(buffers);
      72              :     std::size_t const total_size = buffer_size(buffers);
      73              :     std::size_t total_written = 0;
      74              : 
      75              :     while(total_written < total_size)
      76              :     {
      77              :         auto [ec, n] = co_await stream.write_some(consuming);
      78              :         if(ec)
      79              :             co_return {ec, total_written};
      80              :         consuming.consume(n);
      81              :         total_written += n;
      82              :     }
      83              : 
      84              :     co_return {{}, total_written};
      85           88 : }
      86              : 
      87              : } // namespace capy
      88              : } // namespace boost
      89              : 
      90              : #endif