boost/asio/detail/completion_handler.hpp
//
// detail/completion_handler.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff 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)
//
#ifndef BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP
#define BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/config.hpp>
#include <boost/asio/detail/fenced_block.hpp>
#include <boost/asio/detail/handler_alloc_helpers.hpp>
#include <boost/asio/detail/handler_work.hpp>
#include <boost/asio/detail/memory.hpp>
#include <boost/asio/detail/operation.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
namespace detail {
template <typename Handler>
class completion_handler : public operation
{
public:
BOOST_ASIO_DEFINE_HANDLER_PTR(completion_handler);
completion_handler(Handler& h)
: operation(&completion_handler::do_complete),
handler_(BOOST_ASIO_MOVE_CAST(Handler)(h))
{
handler_work<Handler>::start(handler_);
}
static void do_complete(void* owner, operation* base,
const boost::system::error_code& /*ec*/,
std::size_t /*bytes_transferred*/)
{
// Take ownership of the handler object.
completion_handler* h(static_cast<completion_handler*>(base));
ptr p = { boost::asio::detail::addressof(h->handler_), h, h };
handler_work<Handler> w(h->handler_);
BOOST_ASIO_HANDLER_COMPLETION((*h));
// Make a copy of the handler so that the memory can be deallocated before
// the upcall is made. Even if we're not about to make an upcall, a
// sub-object of the handler may be the true owner of the memory associated
// with the handler. Consequently, a local copy of the handler is required
// to ensure that any owning sub-object remains valid until after we have
// deallocated the memory here.
Handler handler(BOOST_ASIO_MOVE_CAST(Handler)(h->handler_));
p.h = boost::asio::detail::addressof(handler);
p.reset();
// Make the upcall if required.
if (owner)
{
fenced_block b(fenced_block::half);
BOOST_ASIO_HANDLER_INVOCATION_BEGIN(());
w.complete(handler, handler);
BOOST_ASIO_HANDLER_INVOCATION_END;
}
}
private:
Handler handler_;
};
} // namespace detail
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP