asio/detail/io_uring_descriptor_read_op.hpp

0001 //
0002 // detail/io_uring_descriptor_read_op.hpp
0003 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0004 //
0005 // Copyright (c) 2003-2023 Christopher M. Kohlhoff (chris at kohlhoff dot com)
0006 //
0007 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0008 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0009 //
0010
0011 #ifndef BOOST_ASIO_DETAIL_IO_URING_DESCRIPTOR_READ_OP_HPP
0012 #define BOOST_ASIO_DETAIL_IO_URING_DESCRIPTOR_READ_OP_HPP
0013
0014 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
0015 # pragma once
0016 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
0017
0018 #include <boost/asio/detail/config.hpp>
0019
0020 #if defined(BOOST_ASIO_HAS_IO_URING)
0021
0022 #include <boost/asio/detail/bind_handler.hpp>
0023 #include <boost/asio/detail/buffer_sequence_adapter.hpp>
0024 #include <boost/asio/detail/descriptor_ops.hpp>
0025 #include <boost/asio/detail/fenced_block.hpp>
0026 #include <boost/asio/detail/handler_work.hpp>
0027 #include <boost/asio/detail/io_uring_operation.hpp>
0028 #include <boost/asio/detail/memory.hpp>
0029
0030 #include <boost/asio/detail/push_options.hpp>
0031
0032 namespace boost {
0033 namespace asio {
0034 namespace detail {
0035
0036 template <typename MutableBufferSequence>
0037 class io_uring_descriptor_read_op_base : public io_uring_operation
0038 {
0039 public:
0040   io_uring_descriptor_read_op_base(const boost::system::error_code& success_ec,
0041       int descriptor, descriptor_ops::state_type state,
0042       const MutableBufferSequence& buffers, func_type complete_func)
0043     : io_uring_operation(success_ec,
0044         &io_uring_descriptor_read_op_base::do_prepare,
0045         &io_uring_descriptor_read_op_base::do_perform, complete_func),
0046       descriptor_(descriptor),
0047       state_(state),
0048       buffers_(buffers),
0049       bufs_(buffers)
0050   {
0051   }
0052
0053   static void do_prepare(io_uring_operation* base, ::io_uring_sqe* sqe)
0054   {
0055     BOOST_ASIO_ASSUME(base != 0);
0056     io_uring_descriptor_read_op_base* o(
0057         static_cast<io_uring_descriptor_read_op_base*>(base));
0058
0059     if ((o->state_ & descriptor_ops::internal_non_blocking) != 0)
0060     {
0061       ::io_uring_prep_poll_add(sqe, o->descriptor_, POLLIN);
0062     }
0063     else if (o->bufs_.is_single_buffer && o->bufs_.is_registered_buffer)
0064     {
0065       ::io_uring_prep_read_fixed(sqe, o->descriptor_,
0066           o->bufs_.buffers()->iov_base, o->bufs_.buffers()->iov_len,
0067           0, o->bufs_.registered_id().native_handle());
0068     }
0069     else
0070     {
0071       ::io_uring_prep_readv(sqe, o->descriptor_,
0072           o->bufs_.buffers(), o->bufs_.count(), -1);
0073     }
0074   }
0075
0076   static bool do_perform(io_uring_operation* base, bool after_completion)
0077   {
0078     BOOST_ASIO_ASSUME(base != 0);
0079     io_uring_descriptor_read_op_base* o(
0080         static_cast<io_uring_descriptor_read_op_base*>(base));
0081
0082     if ((o->state_ & descriptor_ops::internal_non_blocking) != 0)
0083     {
0084       if (o->bufs_.is_single_buffer)
0085       {
0086         return descriptor_ops::non_blocking_read1(
0087             o->descriptor_, o->bufs_.first(o->buffers_).data(),
0088             o->bufs_.first(o->buffers_).size(), o->ec_,
0089             o->bytes_transferred_);
0090       }
0091       else
0092       {
0093         return descriptor_ops::non_blocking_read(
0094             o->descriptor_, o->bufs_.buffers(), o->bufs_.count(),
0095             o->ec_, o->bytes_transferred_);
0096       }
0097     }
0098     else if (after_completion)
0099     {
0100       if (!o->ec_ && o->bytes_transferred_ == 0)
0101         o->ec_ = boost::asio::error::eof;
0102     }
0103
0104     if (o->ec_ && o->ec_ == boost::asio::error::would_block)
0105     {
0106       o->state_ |= descriptor_ops::internal_non_blocking;
0107       return false;
0108     }
0109
0110     return after_completion;
0111   }
0112
0113 private:
0114   int descriptor_;
0115   descriptor_ops::state_type state_;
0116   MutableBufferSequence buffers_;
0117   buffer_sequence_adapter<boost::asio::mutable_buffer,
0118       MutableBufferSequence> bufs_;
0119 };
0120
0121 template <typename MutableBufferSequence, typename Handler, typename IoExecutor>
0122 class io_uring_descriptor_read_op
0123   : public io_uring_descriptor_read_op_base<MutableBufferSequence>
0124 {
0125 public:
0126   BOOST_ASIO_DEFINE_HANDLER_PTR(io_uring_descriptor_read_op);
0127
0128   io_uring_descriptor_read_op(const boost::system::error_code& success_ec,
0129       int descriptor, descriptor_ops::state_type state,
0130       const MutableBufferSequence& buffers,
0131       Handler& handler, const IoExecutor& io_ex)
0132     : io_uring_descriptor_read_op_base<MutableBufferSequence>(success_ec,
0133         descriptor, state, buffers, &io_uring_descriptor_read_op::do_complete),
0134       handler_(static_cast<Handler&&>(handler)),
0135       work_(handler_, io_ex)
0136   {
0137   }
0138
0139   static void do_complete(void* owner, operation* base,
0140       const boost::system::error_code& /*ec*/,
0141       std::size_t /*bytes_transferred*/)
0142   {
0143     // Take ownership of the handler object.
0144     BOOST_ASIO_ASSUME(base != 0);
0145     io_uring_descriptor_read_op* o
0146       (static_cast<io_uring_descriptor_read_op*>(base));
0147     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
0148
0149     BOOST_ASIO_HANDLER_COMPLETION((*o));
0150
0151     // Take ownership of the operation's outstanding work.
0152     handler_work<Handler, IoExecutor> w(
0153         static_cast<handler_work<Handler, IoExecutor>&&>(
0154           o->work_));
0155
0156     BOOST_ASIO_ERROR_LOCATION(o->ec_);
0157
0158     // Make a copy of the handler so that the memory can be deallocated before
0159     // the upcall is made. Even if we're not about to make an upcall, a
0160     // sub-object of the handler may be the true owner of the memory associated
0161     // with the handler. Consequently, a local copy of the handler is required
0162     // to ensure that any owning sub-object remains valid until after we have
0163     // deallocated the memory here.
0164     detail::binder2<Handler, boost::system::error_code, std::size_t>
0165       handler(o->handler_, o->ec_, o->bytes_transferred_);
0166     p.h = boost::asio::detail::addressof(handler.handler_);
0167     p.reset();
0168
0169     // Make the upcall if required.
0170     if (owner)
0171     {
0172       fenced_block b(fenced_block::half);
0173       BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
0174       w.complete(handler, handler.handler_);
0175       BOOST_ASIO_HANDLER_INVOCATION_END;
0176     }
0177   }
0178
0179 private:
0180   Handler handler_;
0181   handler_work<Handler, IoExecutor> work_;
0182 };
0183
0184 } // namespace detail
0185 } // namespace asio
0186 } // namespace boost
0187
0188 #include <boost/asio/detail/pop_options.hpp>
0189
0190 #endif // defined(BOOST_ASIO_HAS_IO_URING)
0191
0192 #endif // BOOST_ASIO_DETAIL_IO_URING_DESCRIPTOR_READ_OP_HPP