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      1 //
      2 // detail/select_reactor.hpp
      3 // ~~~~~~~~~~~~~~~~~~~~~~~~~
      4 //
      5 // Copyright (c) 2003-2015 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 ASIO_DETAIL_SELECT_REACTOR_HPP
     12 #define ASIO_DETAIL_SELECT_REACTOR_HPP
     13 
     14 
     15 #include "asio/detail/config.hpp"
     16 
     17 #if defined(ASIO_HAS_IOCP)    || (!defined(ASIO_HAS_DEV_POLL)        && !defined(ASIO_HAS_EPOLL)        && !defined(ASIO_HAS_KQUEUE)        && !defined(ASIO_WINDOWS_RUNTIME))
     18 
     19 #include <cstddef>
     20 #include "asio/detail/fd_set_adapter.hpp"
     21 #include "asio/detail/limits.hpp"
     22 #include "asio/detail/mutex.hpp"
     23 #include "asio/detail/op_queue.hpp"
     24 #include "asio/detail/reactor_op.hpp"
     25 #include "asio/detail/reactor_op_queue.hpp"
     26 #include "asio/detail/select_interrupter.hpp"
     27 #include "asio/detail/socket_types.hpp"
     28 #include "asio/detail/timer_queue_base.hpp"
     29 #include "asio/detail/timer_queue_set.hpp"
     30 #include "asio/detail/wait_op.hpp"
     31 #include "asio/io_service.hpp"
     32 
     33 
     34 #include "asio/detail/push_options.hpp"
     35 
     36 namespace asio {
     37 namespace detail {
     38 
     39 class select_reactor
     40   : public asio::detail::service_base<select_reactor>
     41 {
     42 public:
     43   enum op_types { read_op = 0, write_op = 1, except_op = 2,
     44     max_select_ops = 3, connect_op = 1, max_ops = 3 };
     45 
     46   // Per-descriptor data.
     47   struct per_descriptor_data
     48   {
     49   };
     50 
     51   // Constructor.
     52   ASIO_DECL select_reactor(asio::io_service& io_service);
     53 
     54   // Destructor.
     55   ASIO_DECL ~select_reactor();
     56 
     57   // Destroy all user-defined handler objects owned by the service.
     58   ASIO_DECL void shutdown_service();
     59 
     60   // Recreate internal descriptors following a fork.
     61   ASIO_DECL void fork_service(
     62       asio::io_service::fork_event fork_ev);
     63 
     64   // Initialise the task, but only if the reactor is not in its own thread.
     65   ASIO_DECL void init_task();
     66 
     67   // Register a socket with the reactor. Returns 0 on success, system error
     68   // code on failure.
     69   ASIO_DECL int register_descriptor(socket_type, per_descriptor_data&);
     70 
     71   // Register a descriptor with an associated single operation. Returns 0 on
     72   // success, system error code on failure.
     73   ASIO_DECL int register_internal_descriptor(
     74       int op_type, socket_type descriptor,
     75       per_descriptor_data& descriptor_data, reactor_op* op);
     76 
     77   // Post a reactor operation for immediate completion.
     78   void post_immediate_completion(reactor_op* op, bool is_continuation)
     79   {
     80     io_service_.post_immediate_completion(op, is_continuation);
     81   }
     82 
     83   // Start a new operation. The reactor operation will be performed when the
     84   // given descriptor is flagged as ready, or an error has occurred.
     85   ASIO_DECL void start_op(int op_type, socket_type descriptor,
     86       per_descriptor_data&, reactor_op* op, bool is_continuation, bool);
     87 
     88   // Cancel all operations associated with the given descriptor. The
     89   // handlers associated with the descriptor will be invoked with the
     90   // operation_aborted error.
     91   ASIO_DECL void cancel_ops(socket_type descriptor, per_descriptor_data&);
     92 
     93   // Cancel any operations that are running against the descriptor and remove
     94   // its registration from the reactor.
     95   ASIO_DECL void deregister_descriptor(socket_type descriptor,
     96       per_descriptor_data&, bool closing);
     97 
     98   // Remote the descriptor's registration from the reactor.
     99   ASIO_DECL void deregister_internal_descriptor(
    100       socket_type descriptor, per_descriptor_data& descriptor_data);
    101 
    102   // Move descriptor registration from one descriptor_data object to another.
    103   ASIO_DECL void move_descriptor(socket_type descriptor,
    104       per_descriptor_data& target_descriptor_data,
    105       per_descriptor_data& source_descriptor_data);
    106 
    107   // Add a new timer queue to the reactor.
    108   template <typename Time_Traits>
    109   void add_timer_queue(timer_queue<Time_Traits>& queue);
    110 
    111   // Remove a timer queue from the reactor.
    112   template <typename Time_Traits>
    113   void remove_timer_queue(timer_queue<Time_Traits>& queue);
    114 
    115   // Schedule a new operation in the given timer queue to expire at the
    116   // specified absolute time.
    117   template <typename Time_Traits>
    118   void schedule_timer(timer_queue<Time_Traits>& queue,
    119       const typename Time_Traits::time_type& time,
    120       typename timer_queue<Time_Traits>::per_timer_data& timer, wait_op* op);
    121 
    122   // Cancel the timer operations associated with the given token. Returns the
    123   // number of operations that have been posted or dispatched.
    124   template <typename Time_Traits>
    125   std::size_t cancel_timer(timer_queue<Time_Traits>& queue,
    126       typename timer_queue<Time_Traits>::per_timer_data& timer,
    127       std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
    128 
    129   // Run select once until interrupted or events are ready to be dispatched.
    130   ASIO_DECL void run(bool block, op_queue<operation>& ops);
    131 
    132   // Interrupt the select loop.
    133   ASIO_DECL void interrupt();
    134 
    135 private:
    136 
    137   // Helper function to add a new timer queue.
    138   ASIO_DECL void do_add_timer_queue(timer_queue_base& queue);
    139 
    140   // Helper function to remove a timer queue.
    141   ASIO_DECL void do_remove_timer_queue(timer_queue_base& queue);
    142 
    143   // Get the timeout value for the select call.
    144   ASIO_DECL timeval* get_timeout(timeval& tv);
    145 
    146   // Cancel all operations associated with the given descriptor. This function
    147   // does not acquire the select_reactor's mutex.
    148   ASIO_DECL void cancel_ops_unlocked(socket_type descriptor,
    149       const asio::error_code& ec);
    150 
    151   // The io_service implementation used to post completions.
    152   io_service_impl& io_service_;
    153 
    154   // Mutex to protect access to internal data.
    155   asio::detail::mutex mutex_;
    156 
    157   // The interrupter is used to break a blocking select call.
    158   select_interrupter interrupter_;
    159 
    160   // The queues of read, write and except operations.
    161   reactor_op_queue<socket_type> op_queue_[max_ops];
    162 
    163   // The file descriptor sets to be passed to the select system call.
    164   fd_set_adapter fd_sets_[max_select_ops];
    165 
    166   // The timer queues.
    167   timer_queue_set timer_queues_;
    168 
    169 
    170   // Whether the service has been shut down.
    171   bool shutdown_;
    172 };
    173 
    174 } // namespace detail
    175 } // namespace asio
    176 
    177 #include "asio/detail/pop_options.hpp"
    178 
    179 #include "asio/detail/impl/select_reactor.hpp"
    180 # include "asio/detail/impl/select_reactor.ipp"
    181 
    182 #endif // defined(ASIO_HAS_IOCP)
    183        //   || (!defined(ASIO_HAS_DEV_POLL)
    184        //       && !defined(ASIO_HAS_EPOLL)
    185        //       && !defined(ASIO_HAS_KQUEUE)
    186        //       && !defined(ASIO_WINDOWS_RUNTIME))
    187 
    188 #endif // ASIO_DETAIL_SELECT_REACTOR_HPP
    189