asio/detail/io_uring_descriptor_read_at_op.hpp

0001 //
0002 // detail/io_uring_descriptor_read_at_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_AT_OP_HPP
0012 #define BOOST_ASIO_DETAIL_IO_URING_DESCRIPTOR_READ_AT_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/cstdint.hpp>
0025 #include <boost/asio/detail/descriptor_ops.hpp>
0026 #include <boost/asio/detail/fenced_block.hpp>
0027 #include <boost/asio/detail/handler_work.hpp>
0028 #include <boost/asio/detail/io_uring_operation.hpp>
0029 #include <boost/asio/detail/memory.hpp>
0030
0031 #include <boost/asio/detail/push_options.hpp>
0032
0033 namespace boost {
0034 namespace asio {
0035 namespace detail {
0036
0037 template <typename MutableBufferSequence>
0038 class io_uring_descriptor_read_at_op_base : public io_uring_operation
0039 {
0040 public:
0041   io_uring_descriptor_read_at_op_base(
0042       const boost::system::error_code& success_ec, int descriptor,
0043       descriptor_ops::state_type state, uint64_t offset,
0044       const MutableBufferSequence& buffers, func_type complete_func)
0045     : io_uring_operation(success_ec,
0046         &io_uring_descriptor_read_at_op_base::do_prepare,
0047         &io_uring_descriptor_read_at_op_base::do_perform, complete_func),
0048       descriptor_(descriptor),
0049       state_(state),
0050       offset_(offset),
0051       buffers_(buffers),
0052       bufs_(buffers)
0053   {
0054   }
0055
0056   static void do_prepare(io_uring_operation* base, ::io_uring_sqe* sqe)
0057   {
0058     BOOST_ASIO_ASSUME(base != 0);
0059     io_uring_descriptor_read_at_op_base* o(
0060         static_cast<io_uring_descriptor_read_at_op_base*>(base));
0061
0062     if ((o->state_ & descriptor_ops::internal_non_blocking) != 0)
0063     {
0064       ::io_uring_prep_poll_add(sqe, o->descriptor_, POLLIN);
0065     }
0066     else if (o->bufs_.is_single_buffer && o->bufs_.is_registered_buffer)
0067     {
0068       ::io_uring_prep_read_fixed(sqe, o->descriptor_,
0069           o->bufs_.buffers()->iov_base, o->bufs_.buffers()->iov_len,
0070           o->offset_, o->bufs_.registered_id().native_handle());
0071     }
0072     else
0073     {
0074       ::io_uring_prep_readv(sqe, o->descriptor_,
0075           o->bufs_.buffers(), o->bufs_.count(), o->offset_);
0076     }
0077   }
0078
0079   static bool do_perform(io_uring_operation* base, bool after_completion)
0080   {
0081     BOOST_ASIO_ASSUME(base != 0);
0082     io_uring_descriptor_read_at_op_base* o(
0083         static_cast<io_uring_descriptor_read_at_op_base*>(base));
0084
0085     if ((o->state_ & descriptor_ops::internal_non_blocking) != 0)
0086     {
0087       if (o->bufs_.is_single_buffer)
0088       {
0089         return descriptor_ops::non_blocking_read_at1(o->descriptor_,
0090             o->offset_, o->bufs_.first(o->buffers_).data(),
0091             o->bufs_.first(o->buffers_).size(), o->ec_,
0092             o->bytes_transferred_);
0093       }
0094       else
0095       {
0096         return descriptor_ops::non_blocking_read_at(o->descriptor_,
0097             o->offset_, o->bufs_.buffers(), o->bufs_.count(),
0098             o->ec_, o->bytes_transferred_);
0099       }
0100     }
0101     else if (after_completion)
0102     {
0103       if (!o->ec_ && o->bytes_transferred_ == 0)
0104         o->ec_ = boost::asio::error::eof;
0105     }
0106
0107     if (o->ec_ && o->ec_ == boost::asio::error::would_block)
0108     {
0109       o->state_ |= descriptor_ops::internal_non_blocking;
0110       return false;
0111     }
0112
0113     return after_completion;
0114   }
0115
0116 private:
0117   int descriptor_;
0118   descriptor_ops::state_type state_;
0119   uint64_t offset_;
0120   MutableBufferSequence buffers_;
0121   buffer_sequence_adapter<boost::asio::mutable_buffer,
0122       MutableBufferSequence> bufs_;
0123 };
0124
0125 template <typename MutableBufferSequence, typename Handler, typename IoExecutor>
0126 class io_uring_descriptor_read_at_op
0127   : public io_uring_descriptor_read_at_op_base<MutableBufferSequence>
0128 {
0129 public:
0130   BOOST_ASIO_DEFINE_HANDLER_PTR(io_uring_descriptor_read_at_op);
0131
0132   io_uring_descriptor_read_at_op(const boost::system::error_code& success_ec,
0133       int descriptor, descriptor_ops::state_type state, uint64_t offset,
0134       const MutableBufferSequence& buffers,
0135       Handler& handler, const IoExecutor& io_ex)
0136     : io_uring_descriptor_read_at_op_base<MutableBufferSequence>(
0137         success_ec, descriptor, state, offset, buffers,
0138         &io_uring_descriptor_read_at_op::do_complete),
0139       handler_(static_cast<Handler&&>(handler)),
0140       work_(handler_, io_ex)
0141   {
0142   }
0143
0144   static void do_complete(void* owner, operation* base,
0145       const boost::system::error_code& /*ec*/,
0146       std::size_t /*bytes_transferred*/)
0147   {
0148     // Take ownership of the handler object.
0149     BOOST_ASIO_ASSUME(base != 0);
0150     io_uring_descriptor_read_at_op* o
0151       (static_cast<io_uring_descriptor_read_at_op*>(base));
0152     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
0153
0154     BOOST_ASIO_HANDLER_COMPLETION((*o));
0155
0156     // Take ownership of the operation's outstanding work.
0157     handler_work<Handler, IoExecutor> w(
0158         static_cast<handler_work<Handler, IoExecutor>&&>(
0159           o->work_));
0160
0161     BOOST_ASIO_ERROR_LOCATION(o->ec_);
0162
0163     // Make a copy of the handler so that the memory can be deallocated before
0164     // the upcall is made. Even if we're not about to make an upcall, a
0165     // sub-object of the handler may be the true owner of the memory associated
0166     // with the handler. Consequently, a local copy of the handler is required
0167     // to ensure that any owning sub-object remains valid until after we have
0168     // deallocated the memory here.
0169     detail::binder2<Handler, boost::system::error_code, std::size_t>
0170       handler(o->handler_, o->ec_, o->bytes_transferred_);
0171     p.h = boost::asio::detail::addressof(handler.handler_);
0172     p.reset();
0173
0174     // Make the upcall if required.
0175     if (owner)
0176     {
0177       fenced_block b(fenced_block::half);
0178       BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
0179       w.complete(handler, handler.handler_);
0180       BOOST_ASIO_HANDLER_INVOCATION_END;
0181     }
0182   }
0183
0184 private:
0185   Handler handler_;
0186   handler_work<Handler, IoExecutor> work_;
0187 };
0188
0189 } // namespace detail
0190 } // namespace asio
0191 } // namespace boost
0192
0193 #include <boost/asio/detail/pop_options.hpp>
0194
0195 #endif // defined(BOOST_ASIO_HAS_IO_URING)
0196
0197 #endif // BOOST_ASIO_DETAIL_IO_URING_DESCRIPTOR_READ_AT_OP_HPP