ceph/src/boost/boost/asio/basic_signal_set.hpp

   1 //
   2 // basic_signal_set.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 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_BASIC_SIGNAL_SET_HPP
  12 #define BOOST_ASIO_BASIC_SIGNAL_SET_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_ENABLE_OLD_SERVICES)
  21
  22 #include <boost/asio/basic_io_object.hpp>
  23 #include <boost/asio/detail/handler_type_requirements.hpp>
  24 #include <boost/asio/detail/throw_error.hpp>
  25 #include <boost/asio/error.hpp>
  26 #include <boost/asio/signal_set_service.hpp>
  27
  28 #include <boost/asio/detail/push_options.hpp>
  29
  30 namespace boost {
  31 namespace asio {
  32
  33 /// Provides signal functionality.
  34 /**
  35  * The basic_signal_set class template provides the ability to perform an
  36  * asynchronous wait for one or more signals to occur.
  37  *
  38  * Most applications will use the boost::asio::signal_set typedef.
  39  *
  40  * @par Thread Safety
  41  * @e Distinct @e objects: Safe.@n
  42  * @e Shared @e objects: Unsafe.
  43  *
  44  * @par Example
  45  * Performing an asynchronous wait:
  46  * @code
  47  * void handler(
  48  *     const boost::system::error_code& error,
  49  *     int signal_number)
  50  * {
  51  *   if (!error)
  52  *   {
  53  *     // A signal occurred.
  54  *   }
  55  * }
  56  *
  57  * ...
  58  *
  59  * // Construct a signal set registered for process termination.
  60  * boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
  61  *
  62  * // Start an asynchronous wait for one of the signals to occur.
  63  * signals.async_wait(handler);
  64  * @endcode
  65  *
  66  * @par Queueing of signal notifications
  67  *
  68  * If a signal is registered with a signal_set, and the signal occurs when
  69  * there are no waiting handlers, then the signal notification is queued. The
  70  * next async_wait operation on that signal_set will dequeue the notification.
  71  * If multiple notifications are queued, subsequent async_wait operations
  72  * dequeue them one at a time. Signal notifications are dequeued in order of
  73  * ascending signal number.
  74  *
  75  * If a signal number is removed from a signal_set (using the @c remove or @c
  76  * erase member functions) then any queued notifications for that signal are
  77  * discarded.
  78  *
  79  * @par Multiple registration of signals
  80  *
  81  * The same signal number may be registered with different signal_set objects.
  82  * When the signal occurs, one handler is called for each signal_set object.
  83  *
  84  * Note that multiple registration only works for signals that are registered
  85  * using Asio. The application must not also register a signal handler using
  86  * functions such as @c signal() or @c sigaction().
  87  *
  88  * @par Signal masking on POSIX platforms
  89  *
  90  * POSIX allows signals to be blocked using functions such as @c sigprocmask()
  91  * and @c pthread_sigmask(). For signals to be delivered, programs must ensure
  92  * that any signals registered using signal_set objects are unblocked in at
  93  * least one thread.
  94  */
  95 template <typename SignalSetService = signal_set_service>
  96 class basic_signal_set
  97   : public basic_io_object<SignalSetService>
  98 {
  99 public:
 100   /// Construct a signal set without adding any signals.
 101   /**
 102    * This constructor creates a signal set without registering for any signals.
 103    *
 104    * @param io_context The io_context object that the signal set will use to
 105    * dispatch handlers for any asynchronous operations performed on the set.
 106    */
 107   explicit basic_signal_set(boost::asio::io_context& io_context)
 108     : basic_io_object<SignalSetService>(io_context)
 109   {
 110   }
 111
 112   /// Construct a signal set and add one signal.
 113   /**
 114    * This constructor creates a signal set and registers for one signal.
 115    *
 116    * @param io_context The io_context object that the signal set will use to
 117    * dispatch handlers for any asynchronous operations performed on the set.
 118    *
 119    * @param signal_number_1 The signal number to be added.
 120    *
 121    * @note This constructor is equivalent to performing:
 122    * @code boost::asio::signal_set signals(io_context);
 123    * signals.add(signal_number_1); @endcode
 124    */
 125   basic_signal_set(boost::asio::io_context& io_context, int signal_number_1)
 126     : basic_io_object<SignalSetService>(io_context)
 127   {
 128     boost::system::error_code ec;
 129     this->get_service().add(this->get_implementation(), signal_number_1, ec);
 130     boost::asio::detail::throw_error(ec, "add");
 131   }
 132
 133   /// Construct a signal set and add two signals.
 134   /**
 135    * This constructor creates a signal set and registers for two signals.
 136    *
 137    * @param io_context The io_context object that the signal set will use to
 138    * dispatch handlers for any asynchronous operations performed on the set.
 139    *
 140    * @param signal_number_1 The first signal number to be added.
 141    *
 142    * @param signal_number_2 The second signal number to be added.
 143    *
 144    * @note This constructor is equivalent to performing:
 145    * @code boost::asio::signal_set signals(io_context);
 146    * signals.add(signal_number_1);
 147    * signals.add(signal_number_2); @endcode
 148    */
 149   basic_signal_set(boost::asio::io_context& io_context, int signal_number_1,
 150       int signal_number_2)
 151     : basic_io_object<SignalSetService>(io_context)
 152   {
 153     boost::system::error_code ec;
 154     this->get_service().add(this->get_implementation(), signal_number_1, ec);
 155     boost::asio::detail::throw_error(ec, "add");
 156     this->get_service().add(this->get_implementation(), signal_number_2, ec);
 157     boost::asio::detail::throw_error(ec, "add");
 158   }
 159
 160   /// Construct a signal set and add three signals.
 161   /**
 162    * This constructor creates a signal set and registers for three signals.
 163    *
 164    * @param io_context The io_context object that the signal set will use to
 165    * dispatch handlers for any asynchronous operations performed on the set.
 166    *
 167    * @param signal_number_1 The first signal number to be added.
 168    *
 169    * @param signal_number_2 The second signal number to be added.
 170    *
 171    * @param signal_number_3 The third signal number to be added.
 172    *
 173    * @note This constructor is equivalent to performing:
 174    * @code boost::asio::signal_set signals(io_context);
 175    * signals.add(signal_number_1);
 176    * signals.add(signal_number_2);
 177    * signals.add(signal_number_3); @endcode
 178    */
 179   basic_signal_set(boost::asio::io_context& io_context, int signal_number_1,
 180       int signal_number_2, int signal_number_3)
 181     : basic_io_object<SignalSetService>(io_context)
 182   {
 183     boost::system::error_code ec;
 184     this->get_service().add(this->get_implementation(), signal_number_1, ec);
 185     boost::asio::detail::throw_error(ec, "add");
 186     this->get_service().add(this->get_implementation(), signal_number_2, ec);
 187     boost::asio::detail::throw_error(ec, "add");
 188     this->get_service().add(this->get_implementation(), signal_number_3, ec);
 189     boost::asio::detail::throw_error(ec, "add");
 190   }
 191
 192   /// Add a signal to a signal_set.
 193   /**
 194    * This function adds the specified signal to the set. It has no effect if the
 195    * signal is already in the set.
 196    *
 197    * @param signal_number The signal to be added to the set.
 198    *
 199    * @throws boost::system::system_error Thrown on failure.
 200    */
 201   void add(int signal_number)
 202   {
 203     boost::system::error_code ec;
 204     this->get_service().add(this->get_implementation(), signal_number, ec);
 205     boost::asio::detail::throw_error(ec, "add");
 206   }
 207
 208   /// Add a signal to a signal_set.
 209   /**
 210    * This function adds the specified signal to the set. It has no effect if the
 211    * signal is already in the set.
 212    *
 213    * @param signal_number The signal to be added to the set.
 214    *
 215    * @param ec Set to indicate what error occurred, if any.
 216    */
 217   BOOST_ASIO_SYNC_OP_VOID add(int signal_number, boost::system::error_code& ec)
 218   {
 219     this->get_service().add(this->get_implementation(), signal_number, ec);
 220     BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
 221   }
 222
 223   /// Remove a signal from a signal_set.
 224   /**
 225    * This function removes the specified signal from the set. It has no effect
 226    * if the signal is not in the set.
 227    *
 228    * @param signal_number The signal to be removed from the set.
 229    *
 230    * @throws boost::system::system_error Thrown on failure.
 231    *
 232    * @note Removes any notifications that have been queued for the specified
 233    * signal number.
 234    */
 235   void remove(int signal_number)
 236   {
 237     boost::system::error_code ec;
 238     this->get_service().remove(this->get_implementation(), signal_number, ec);
 239     boost::asio::detail::throw_error(ec, "remove");
 240   }
 241
 242   /// Remove a signal from a signal_set.
 243   /**
 244    * This function removes the specified signal from the set. It has no effect
 245    * if the signal is not in the set.
 246    *
 247    * @param signal_number The signal to be removed from the set.
 248    *
 249    * @param ec Set to indicate what error occurred, if any.
 250    *
 251    * @note Removes any notifications that have been queued for the specified
 252    * signal number.
 253    */
 254   BOOST_ASIO_SYNC_OP_VOID remove(int signal_number,
 255       boost::system::error_code& ec)
 256   {
 257     this->get_service().remove(this->get_implementation(), signal_number, ec);
 258     BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
 259   }
 260
 261   /// Remove all signals from a signal_set.
 262   /**
 263    * This function removes all signals from the set. It has no effect if the set
 264    * is already empty.
 265    *
 266    * @throws boost::system::system_error Thrown on failure.
 267    *
 268    * @note Removes all queued notifications.
 269    */
 270   void clear()
 271   {
 272     boost::system::error_code ec;
 273     this->get_service().clear(this->get_implementation(), ec);
 274     boost::asio::detail::throw_error(ec, "clear");
 275   }
 276
 277   /// Remove all signals from a signal_set.
 278   /**
 279    * This function removes all signals from the set. It has no effect if the set
 280    * is already empty.
 281    *
 282    * @param ec Set to indicate what error occurred, if any.
 283    *
 284    * @note Removes all queued notifications.
 285    */
 286   BOOST_ASIO_SYNC_OP_VOID clear(boost::system::error_code& ec)
 287   {
 288     this->get_service().clear(this->get_implementation(), ec);
 289     BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
 290   }
 291
 292   /// Cancel all operations associated with the signal set.
 293   /**
 294    * This function forces the completion of any pending asynchronous wait
 295    * operations against the signal set. The handler for each cancelled
 296    * operation will be invoked with the boost::asio::error::operation_aborted
 297    * error code.
 298    *
 299    * Cancellation does not alter the set of registered signals.
 300    *
 301    * @throws boost::system::system_error Thrown on failure.
 302    *
 303    * @note If a registered signal occurred before cancel() is called, then the
 304    * handlers for asynchronous wait operations will:
 305    *
 306    * @li have already been invoked; or
 307    *
 308    * @li have been queued for invocation in the near future.
 309    *
 310    * These handlers can no longer be cancelled, and therefore are passed an
 311    * error code that indicates the successful completion of the wait operation.
 312    */
 313   void cancel()
 314   {
 315     boost::system::error_code ec;
 316     this->get_service().cancel(this->get_implementation(), ec);
 317     boost::asio::detail::throw_error(ec, "cancel");
 318   }
 319
 320   /// Cancel all operations associated with the signal set.
 321   /**
 322    * This function forces the completion of any pending asynchronous wait
 323    * operations against the signal set. The handler for each cancelled
 324    * operation will be invoked with the boost::asio::error::operation_aborted
 325    * error code.
 326    *
 327    * Cancellation does not alter the set of registered signals.
 328    *
 329    * @param ec Set to indicate what error occurred, if any.
 330    *
 331    * @note If a registered signal occurred before cancel() is called, then the
 332    * handlers for asynchronous wait operations will:
 333    *
 334    * @li have already been invoked; or
 335    *
 336    * @li have been queued for invocation in the near future.
 337    *
 338    * These handlers can no longer be cancelled, and therefore are passed an
 339    * error code that indicates the successful completion of the wait operation.
 340    */
 341   BOOST_ASIO_SYNC_OP_VOID cancel(boost::system::error_code& ec)
 342   {
 343     this->get_service().cancel(this->get_implementation(), ec);
 344     BOOST_ASIO_SYNC_OP_VOID_RETURN(ec);
 345   }
 346
 347   /// Start an asynchronous operation to wait for a signal to be delivered.
 348   /**
 349    * This function may be used to initiate an asynchronous wait against the
 350    * signal set. It always returns immediately.
 351    *
 352    * For each call to async_wait(), the supplied handler will be called exactly
 353    * once. The handler will be called when:
 354    *
 355    * @li One of the registered signals in the signal set occurs; or
 356    *
 357    * @li The signal set was cancelled, in which case the handler is passed the
 358    * error code boost::asio::error::operation_aborted.
 359    *
 360    * @param handler The handler to be called when the signal occurs. Copies
 361    * will be made of the handler as required. The function signature of the
 362    * handler must be:
 363    * @code void handler(
 364    *   const boost::system::error_code& error, // Result of operation.
 365    *   int signal_number // Indicates which signal occurred.
 366    * ); @endcode
 367    * Regardless of whether the asynchronous operation completes immediately or
 368    * not, the handler will not be invoked from within this function. Invocation
 369    * of the handler will be performed in a manner equivalent to using
 370    * boost::asio::io_context::post().
 371    */
 372   template <typename SignalHandler>
 373   BOOST_ASIO_INITFN_RESULT_TYPE(SignalHandler,
 374       void (boost::system::error_code, int))
 375   async_wait(BOOST_ASIO_MOVE_ARG(SignalHandler) handler)
 376   {
 377     // If you get an error on the following line it means that your handler does
 378     // not meet the documented type requirements for a SignalHandler.
 379     BOOST_ASIO_SIGNAL_HANDLER_CHECK(SignalHandler, handler) type_check;
 380
 381     return this->get_service().async_wait(this->get_implementation(),
 382         BOOST_ASIO_MOVE_CAST(SignalHandler)(handler));
 383   }
 384 };
 385
 386 } // namespace asio
 387 } // namespace boost
 388
 389 #include <boost/asio/detail/pop_options.hpp>
 390
 391 #endif // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 392
 393 #endif // BOOST_ASIO_BASIC_SIGNAL_SET_HPP