boost/beast/core/impl/buffered_read_stream.ipp
//
// Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/beast
//
#ifndef BOOST_BEAST_IMPL_BUFFERED_READ_STREAM_IPP
#define BOOST_BEAST_IMPL_BUFFERED_READ_STREAM_IPP
#include <boost/beast/core/bind_handler.hpp>
#include <boost/beast/core/error.hpp>
#include <boost/beast/core/handler_ptr.hpp>
#include <boost/beast/core/read_size.hpp>
#include <boost/beast/core/type_traits.hpp>
#include <boost/beast/core/detail/config.hpp>
#include <boost/asio/associated_allocator.hpp>
#include <boost/asio/associated_executor.hpp>
#include <boost/asio/executor_work_guard.hpp>
#include <boost/asio/handler_continuation_hook.hpp>
#include <boost/asio/handler_invoke_hook.hpp>
#include <boost/asio/post.hpp>
#include <boost/throw_exception.hpp>
namespace boost {
namespace beast {
template<class Stream, class DynamicBuffer>
template<class MutableBufferSequence, class Handler>
class buffered_read_stream<
Stream, DynamicBuffer>::read_some_op
{
buffered_read_stream& s_;
boost::asio::executor_work_guard<decltype(
std::declval<Stream&>().get_executor())> wg_;
MutableBufferSequence b_;
Handler h_;
int step_ = 0;
public:
read_some_op(read_some_op&&) = default;
read_some_op(read_some_op const&) = delete;
template<class DeducedHandler, class... Args>
read_some_op(DeducedHandler&& h,
buffered_read_stream& s,
MutableBufferSequence const& b)
: s_(s)
, wg_(s_.get_executor())
, b_(b)
, h_(std::forward<DeducedHandler>(h))
{
}
using allocator_type =
boost::asio::associated_allocator_t<Handler>;
allocator_type
get_allocator() const noexcept
{
return (boost::asio::get_associated_allocator)(h_);
}
using executor_type =
boost::asio::associated_executor_t<Handler, decltype(
std::declval<buffered_read_stream&>().get_executor())>;
executor_type
get_executor() const noexcept
{
return (boost::asio::get_associated_executor)(
h_, s_.get_executor());
}
void
operator()(error_code const& ec,
std::size_t bytes_transferred);
friend
bool asio_handler_is_continuation(read_some_op* op)
{
using boost::asio::asio_handler_is_continuation;
return asio_handler_is_continuation(
std::addressof(op->h_));
}
template<class Function>
friend
void asio_handler_invoke(Function&& f, read_some_op* op)
{
using boost::asio::asio_handler_invoke;
asio_handler_invoke(f, std::addressof(op->h_));
}
};
template<class Stream, class DynamicBuffer>
template<class MutableBufferSequence, class Handler>
void
buffered_read_stream<Stream, DynamicBuffer>::
read_some_op<MutableBufferSequence, Handler>::operator()(
error_code const& ec, std::size_t bytes_transferred)
{
switch(step_)
{
case 0:
if(s_.buffer_.size() == 0)
{
if(s_.capacity_ == 0)
{
// read (unbuffered)
step_ = 1;
return s_.next_layer_.async_read_some(
b_, std::move(*this));
}
// read
step_ = 2;
return s_.next_layer_.async_read_some(
s_.buffer_.prepare(read_size(
s_.buffer_, s_.capacity_)),
std::move(*this));
}
step_ = 3;
return boost::asio::post(
s_.get_executor(),
bind_handler(std::move(*this), ec, 0));
case 1:
// upcall
break;
case 2:
s_.buffer_.commit(bytes_transferred);
BOOST_FALLTHROUGH;
case 3:
bytes_transferred =
boost::asio::buffer_copy(b_, s_.buffer_.data());
s_.buffer_.consume(bytes_transferred);
break;
}
h_(ec, bytes_transferred);
}
//------------------------------------------------------------------------------
template<class Stream, class DynamicBuffer>
template<class... Args>
buffered_read_stream<Stream, DynamicBuffer>::
buffered_read_stream(Args&&... args)
: next_layer_(std::forward<Args>(args)...)
{
}
template<class Stream, class DynamicBuffer>
template<class ConstBufferSequence, class WriteHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
WriteHandler, void(error_code, std::size_t))
buffered_read_stream<Stream, DynamicBuffer>::
async_write_some(
ConstBufferSequence const& buffers,
WriteHandler&& handler)
{
static_assert(is_async_write_stream<next_layer_type>::value,
"AsyncWriteStream requirements not met");
static_assert(boost::asio::is_const_buffer_sequence<
ConstBufferSequence>::value,
"ConstBufferSequence requirements not met");
static_assert(is_completion_handler<WriteHandler,
void(error_code, std::size_t)>::value,
"WriteHandler requirements not met");
return next_layer_.async_write_some(buffers,
std::forward<WriteHandler>(handler));
}
template<class Stream, class DynamicBuffer>
template<class MutableBufferSequence>
std::size_t
buffered_read_stream<Stream, DynamicBuffer>::
read_some(
MutableBufferSequence const& buffers)
{
static_assert(is_sync_read_stream<next_layer_type>::value,
"SyncReadStream requirements not met");
static_assert(boost::asio::is_mutable_buffer_sequence<
MutableBufferSequence>::value,
"MutableBufferSequence requirements not met");
error_code ec;
auto n = read_some(buffers, ec);
if(ec)
BOOST_THROW_EXCEPTION(system_error{ec});
return n;
}
template<class Stream, class DynamicBuffer>
template<class MutableBufferSequence>
std::size_t
buffered_read_stream<Stream, DynamicBuffer>::
read_some(MutableBufferSequence const& buffers,
error_code& ec)
{
static_assert(is_sync_read_stream<next_layer_type>::value,
"SyncReadStream requirements not met");
static_assert(boost::asio::is_mutable_buffer_sequence<
MutableBufferSequence>::value,
"MutableBufferSequence requirements not met");
using boost::asio::buffer_size;
using boost::asio::buffer_copy;
if(buffer_.size() == 0)
{
if(capacity_ == 0)
return next_layer_.read_some(buffers, ec);
buffer_.commit(next_layer_.read_some(
buffer_.prepare(read_size(buffer_,
capacity_)), ec));
if(ec)
return 0;
}
else
{
ec.assign(0, ec.category());
}
auto bytes_transferred =
buffer_copy(buffers, buffer_.data());
buffer_.consume(bytes_transferred);
return bytes_transferred;
}
template<class Stream, class DynamicBuffer>
template<class MutableBufferSequence, class ReadHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(
ReadHandler, void(error_code, std::size_t))
buffered_read_stream<Stream, DynamicBuffer>::
async_read_some(
MutableBufferSequence const& buffers,
ReadHandler&& handler)
{
static_assert(is_async_read_stream<next_layer_type>::value,
"AsyncReadStream requirements not met");
static_assert(boost::asio::is_mutable_buffer_sequence<
MutableBufferSequence>::value,
"MutableBufferSequence requirements not met");
if(buffer_.size() == 0 && capacity_ == 0)
return next_layer_.async_read_some(buffers,
std::forward<ReadHandler>(handler));
BOOST_BEAST_HANDLER_INIT(
ReadHandler, void(error_code, std::size_t));
read_some_op<MutableBufferSequence, BOOST_ASIO_HANDLER_TYPE(
ReadHandler, void(error_code, std::size_t))>{
std::move(init.completion_handler), *this, buffers}(
error_code{}, 0);
return init.result.get();
}
} // beast
} // boost
#endif