include/boost/corosio/native/detail/reactor/reactor_signal_pipe.hpp
100.0% Lines (7/7)
100.0% List of functions (2/2)
Functions (2)
| Line | TLA | Hits | Source Code |
|---|---|---|---|
| 1 | // | ||
| 2 | // Copyright (c) 2026 Michael Vandeberg | ||
| 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/corosio | ||
| 8 | // | ||
| 9 | |||
| 10 | #ifndef BOOST_COROSIO_NATIVE_DETAIL_REACTOR_REACTOR_SIGNAL_PIPE_HPP | ||
| 11 | #define BOOST_COROSIO_NATIVE_DETAIL_REACTOR_REACTOR_SIGNAL_PIPE_HPP | ||
| 12 | |||
| 13 | #include <boost/corosio/detail/platform.hpp> | ||
| 14 | |||
| 15 | #if BOOST_COROSIO_POSIX | ||
| 16 | |||
| 17 | #include <boost/corosio/native/detail/posix/posix_signal_service.hpp> | ||
| 18 | #include <boost/corosio/native/detail/reactor/reactor_descriptor_state.hpp> | ||
| 19 | #include <boost/corosio/native/detail/reactor/reactor_op_base.hpp> | ||
| 20 | |||
| 21 | #include <errno.h> | ||
| 22 | |||
| 23 | /* | ||
| 24 | Reactor signal-pipe reader | ||
| 25 | ========================== | ||
| 26 | |||
| 27 | Bridges the global POSIX signal self-pipe (see posix_signal_service.hpp) | ||
| 28 | to the reactor backends (epoll/kqueue/select). The concrete scheduler owns | ||
| 29 | one of these for its lifetime and, in register_signal_reader(), parks the | ||
| 30 | drain op as the descriptor's read_op then calls register_descriptor(). | ||
| 31 | |||
| 32 | The drain op never completes: on each read-readiness edge, invoke_deferred_io | ||
| 33 | calls perform_io(), which drains the pipe and delivers the pending signals, | ||
| 34 | then reports EAGAIN so the op stays parked and re-fires on the next edge — | ||
| 35 | exactly the path a socket read op takes when the kernel has no more data. | ||
| 36 | Because deliver_signal() runs here, in normal dispatch context (not in the | ||
| 37 | signal handler and not under the reactor poll lock), its mutex locking is | ||
| 38 | safe. | ||
| 39 | */ | ||
| 40 | |||
| 41 | namespace boost::corosio::detail { | ||
| 42 | |||
| 43 | struct reactor_signal_pipe_reader | ||
| 44 | { | ||
| 45 | // Parked read op: drains the self-pipe and re-arms via EAGAIN. | ||
| 46 | struct drain_op final : reactor_op_base | ||
| 47 | { | ||
| 48 | 300x | void perform_io() noexcept override | |
| 49 | { | ||
| 50 | 300x | posix_signal_detail::drain_signal_pipe(); | |
| 51 | // Stay parked: EAGAIN tells invoke_deferred_io to keep this op | ||
| 52 | // installed as read_op and re-run it on the next readiness edge. | ||
| 53 | 300x | errn = EAGAIN; | |
| 54 | 300x | } | |
| 55 | }; | ||
| 56 | |||
| 57 | reactor_descriptor_state desc; | ||
| 58 | drain_op op; | ||
| 59 | |||
| 60 | // Park the drain op and return the descriptor to hand to | ||
| 61 | // scheduler::register_descriptor(read_fd, ...). | ||
| 62 | 82x | reactor_descriptor_state* arm() noexcept | |
| 63 | { | ||
| 64 | 82x | desc.read_op = &op; | |
| 65 | 82x | return &desc; | |
| 66 | } | ||
| 67 | }; | ||
| 68 | |||
| 69 | } // namespace boost::corosio::detail | ||
| 70 | |||
| 71 | #endif // BOOST_COROSIO_POSIX | ||
| 72 | |||
| 73 | #endif // BOOST_COROSIO_NATIVE_DETAIL_REACTOR_REACTOR_SIGNAL_PIPE_HPP | ||
| 74 |