ceph/src/boost/boost/asio/detail/dev_poll_reactor.hpp

   1 //
   2 // detail/dev_poll_reactor.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP
  12 #define BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19
  20 #if defined(BOOST_ASIO_HAS_DEV_POLL)
  21
  22 #include <cstddef>
  23 #include <vector>
  24 #include <sys/devpoll.h>
  25 #include <boost/asio/detail/hash_map.hpp>
  26 #include <boost/asio/detail/limits.hpp>
  27 #include <boost/asio/detail/mutex.hpp>
  28 #include <boost/asio/detail/op_queue.hpp>
  29 #include <boost/asio/detail/reactor_op.hpp>
  30 #include <boost/asio/detail/reactor_op_queue.hpp>
  31 #include <boost/asio/detail/scheduler_task.hpp>
  32 #include <boost/asio/detail/select_interrupter.hpp>
  33 #include <boost/asio/detail/socket_types.hpp>
  34 #include <boost/asio/detail/timer_queue_base.hpp>
  35 #include <boost/asio/detail/timer_queue_set.hpp>
  36 #include <boost/asio/detail/wait_op.hpp>
  37 #include <boost/asio/execution_context.hpp>
  38
  39 #include <boost/asio/detail/push_options.hpp>
  40
  41 namespace boost {
  42 namespace asio {
  43 namespace detail {
  44
  45 class dev_poll_reactor
  46   : public execution_context_service_base<dev_poll_reactor>,
  47     public scheduler_task
  48 {
  49 public:
  50   enum op_types { read_op = 0, write_op = 1,
  51     connect_op = 1, except_op = 2, max_ops = 3 };
  52
  53   // Per-descriptor data.
  54   struct per_descriptor_data
  55   {
  56   };
  57
  58   // Constructor.
  59   BOOST_ASIO_DECL dev_poll_reactor(boost::asio::execution_context& ctx);
  60
  61   // Destructor.
  62   BOOST_ASIO_DECL ~dev_poll_reactor();
  63
  64   // Destroy all user-defined handler objects owned by the service.
  65   BOOST_ASIO_DECL void shutdown();
  66
  67   // Recreate internal descriptors following a fork.
  68   BOOST_ASIO_DECL void notify_fork(
  69       boost::asio::execution_context::fork_event fork_ev);
  70
  71   // Initialise the task.
  72   BOOST_ASIO_DECL void init_task();
  73
  74   // Register a socket with the reactor. Returns 0 on success, system error
  75   // code on failure.
  76   BOOST_ASIO_DECL int register_descriptor(socket_type, per_descriptor_data&);
  77
  78   // Register a descriptor with an associated single operation. Returns 0 on
  79   // success, system error code on failure.
  80   BOOST_ASIO_DECL int register_internal_descriptor(
  81       int op_type, socket_type descriptor,
  82       per_descriptor_data& descriptor_data, reactor_op* op);
  83
  84   // Move descriptor registration from one descriptor_data object to another.
  85   BOOST_ASIO_DECL void move_descriptor(socket_type descriptor,
  86       per_descriptor_data& target_descriptor_data,
  87       per_descriptor_data& source_descriptor_data);
  88
  89   // Post a reactor operation for immediate completion.
  90   void post_immediate_completion(reactor_op* op, bool is_continuation);
  91
  92   // Start a new operation. The reactor operation will be performed when the
  93   // given descriptor is flagged as ready, or an error has occurred.
  94   BOOST_ASIO_DECL void start_op(int op_type, socket_type descriptor,
  95       per_descriptor_data&, reactor_op* op,
  96       bool is_continuation, bool allow_speculative);
  97
  98   // Cancel all operations associated with the given descriptor. The
  99   // handlers associated with the descriptor will be invoked with the
 100   // operation_aborted error.
 101   BOOST_ASIO_DECL void cancel_ops(socket_type descriptor, per_descriptor_data&);
 102
 103   // Cancel all operations associated with the given descriptor and key. The
 104   // handlers associated with the descriptor will be invoked with the
 105   // operation_aborted error.
 106   BOOST_ASIO_DECL void cancel_ops_by_key(socket_type descriptor,
 107       per_descriptor_data& descriptor_data,
 108       int op_type, void* cancellation_key);
 109
 110   // Cancel any operations that are running against the descriptor and remove
 111   // its registration from the reactor. The reactor resources associated with
 112   // the descriptor must be released by calling cleanup_descriptor_data.
 113   BOOST_ASIO_DECL void deregister_descriptor(socket_type descriptor,
 114       per_descriptor_data&, bool closing);
 115
 116   // Remove the descriptor's registration from the reactor. The reactor
 117   // resources associated with the descriptor must be released by calling
 118   // cleanup_descriptor_data.
 119   BOOST_ASIO_DECL void deregister_internal_descriptor(
 120       socket_type descriptor, per_descriptor_data&);
 121
 122   // Perform any post-deregistration cleanup tasks associated with the
 123   // descriptor data.
 124   BOOST_ASIO_DECL void cleanup_descriptor_data(per_descriptor_data&);
 125
 126   // Add a new timer queue to the reactor.
 127   template <typename Time_Traits>
 128   void add_timer_queue(timer_queue<Time_Traits>& queue);
 129
 130   // Remove a timer queue from the reactor.
 131   template <typename Time_Traits>
 132   void remove_timer_queue(timer_queue<Time_Traits>& queue);
 133
 134   // Schedule a new operation in the given timer queue to expire at the
 135   // specified absolute time.
 136   template <typename Time_Traits>
 137   void schedule_timer(timer_queue<Time_Traits>& queue,
 138       const typename Time_Traits::time_type& time,
 139       typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
 140
 141   // Cancel the timer operations associated with the given token. Returns the
 142   // number of operations that have been posted or dispatched.
 143   template <typename Time_Traits>
 144   std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
 145       typename timer_queue<Time_Traits>::per_timer_data& timer,
 146       std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
 147
 148   // Cancel the timer operations associated with the given key.
 149   template <typename Time_Traits>
 150   void cancel_timer_by_key(timer_queue<Time_Traits>& queue,
 151       typename timer_queue<Time_Traits>::per_timer_data* timer,
 152       void* cancellation_key);
 153
 154   // Move the timer operations associated with the given timer.
 155   template <typename Time_Traits>
 156   void move_timer(timer_queue<Time_Traits>& queue,
 157       typename timer_queue<Time_Traits>::per_timer_data& target,
 158       typename timer_queue<Time_Traits>::per_timer_data& source);
 159
 160   // Run /dev/poll once until interrupted or events are ready to be dispatched.
 161   BOOST_ASIO_DECL void run(long usec, op_queue<operation>& ops);
 162
 163   // Interrupt the select loop.
 164   BOOST_ASIO_DECL void interrupt();
 165
 166 private:
 167   // Create the /dev/poll file descriptor. Throws an exception if the descriptor
 168   // cannot be created.
 169   BOOST_ASIO_DECL static int do_dev_poll_create();
 170
 171   // Helper function to add a new timer queue.
 172   BOOST_ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
 173
 174   // Helper function to remove a timer queue.
 175   BOOST_ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
 176
 177   // Get the timeout value for the /dev/poll DP_POLL operation. The timeout
 178   // value is returned as a number of milliseconds. A return value of -1
 179   // indicates that the poll should block indefinitely.
 180   BOOST_ASIO_DECL int get_timeout(int msec);
 181
 182   // Cancel all operations associated with the given descriptor. The do_cancel
 183   // function of the handler objects will be invoked. This function does not
 184   // acquire the dev_poll_reactor's mutex.
 185   BOOST_ASIO_DECL void cancel_ops_unlocked(socket_type descriptor,
 186       const boost::system::error_code& ec);
 187
 188   // Add a pending event entry for the given descriptor.
 189   BOOST_ASIO_DECL ::pollfd& add_pending_event_change(int descriptor);
 190
 191   // The scheduler implementation used to post completions.
 192   scheduler& scheduler_;
 193
 194   // Mutex to protect access to internal data.
 195   boost::asio::detail::mutex mutex_;
 196
 197   // The /dev/poll file descriptor.
 198   int dev_poll_fd_;
 199
 200   // Vector of /dev/poll events waiting to be written to the descriptor.
 201   std::vector< ::pollfd> pending_event_changes_;
 202
 203   // Hash map to associate a descriptor with a pending event change index.
 204   hash_map<int, std::size_t> pending_event_change_index_;
 205
 206   // The interrupter is used to break a blocking DP_POLL operation.
 207   select_interrupter interrupter_;
 208
 209   // The queues of read, write and except operations.
 210   reactor_op_queue<socket_type> op_queue_[max_ops];
 211
 212   // The timer queues.
 213   timer_queue_set timer_queues_;
 214
 215   // Whether the service has been shut down.
 216   bool shutdown_;
 217 };
 218
 219 } // namespace detail
 220 } // namespace asio
 221 } // namespace boost
 222
 223 #include <boost/asio/detail/pop_options.hpp>
 224
 225 #include <boost/asio/detail/impl/dev_poll_reactor.hpp>
 226 #if defined(BOOST_ASIO_HEADER_ONLY)
 227 # include <boost/asio/detail/impl/dev_poll_reactor.ipp>
 228 #endif // defined(BOOST_ASIO_HEADER_ONLY)
 229
 230 #endif // defined(BOOST_ASIO_HAS_DEV_POLL)
 231
 232 #endif // BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP