ceph/src/boost/boost/asio/basic_deadline_timer.hpp

   1 //
   2 // basic_deadline_timer.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_DEADLINE_TIMER_HPP
  12 #define BOOST_ASIO_BASIC_DEADLINE_TIMER_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_BOOST_DATE_TIME) \
  21   || defined(GENERATING_DOCUMENTATION)
  22
  23 #include <cstddef>
  24 #include <boost/asio/basic_io_object.hpp>
  25 #include <boost/asio/detail/handler_type_requirements.hpp>
  26 #include <boost/asio/detail/throw_error.hpp>
  27 #include <boost/asio/error.hpp>
  28 #include <boost/asio/time_traits.hpp>
  29
  30 #if defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
  31 # include <boost/asio/deadline_timer_service.hpp>
  32 #else // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
  33 # include <boost/asio/detail/deadline_timer_service.hpp>
  34 # define BOOST_ASIO_SVC_T detail::deadline_timer_service<TimeTraits>
  35 #endif // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
  36
  37 #include <boost/asio/detail/push_options.hpp>
  38
  39 namespace boost {
  40 namespace asio {
  41
  42 /// Provides waitable timer functionality.
  43 /**
  44  * The basic_deadline_timer class template provides the ability to perform a
  45  * blocking or asynchronous wait for a timer to expire.
  46  *
  47  * A deadline timer is always in one of two states: "expired" or "not expired".
  48  * If the wait() or async_wait() function is called on an expired timer, the
  49  * wait operation will complete immediately.
  50  *
  51  * Most applications will use the boost::asio::deadline_timer typedef.
  52  *
  53  * @par Thread Safety
  54  * @e Distinct @e objects: Safe.@n
  55  * @e Shared @e objects: Unsafe.
  56  *
  57  * @par Examples
  58  * Performing a blocking wait:
  59  * @code
  60  * // Construct a timer without setting an expiry time.
  61  * boost::asio::deadline_timer timer(io_context);
  62  *
  63  * // Set an expiry time relative to now.
  64  * timer.expires_from_now(boost::posix_time::seconds(5));
  65  *
  66  * // Wait for the timer to expire.
  67  * timer.wait();
  68  * @endcode
  69  *
  70  * @par
  71  * Performing an asynchronous wait:
  72  * @code
  73  * void handler(const boost::system::error_code& error)
  74  * {
  75  *   if (!error)
  76  *   {
  77  *     // Timer expired.
  78  *   }
  79  * }
  80  *
  81  * ...
  82  *
  83  * // Construct a timer with an absolute expiry time.
  84  * boost::asio::deadline_timer timer(io_context,
  85  *     boost::posix_time::time_from_string("2005-12-07 23:59:59.000"));
  86  *
  87  * // Start an asynchronous wait.
  88  * timer.async_wait(handler);
  89  * @endcode
  90  *
  91  * @par Changing an active deadline_timer's expiry time
  92  *
  93  * Changing the expiry time of a timer while there are pending asynchronous
  94  * waits causes those wait operations to be cancelled. To ensure that the action
  95  * associated with the timer is performed only once, use something like this:
  96  * used:
  97  *
  98  * @code
  99  * void on_some_event()
 100  * {
 101  *   if (my_timer.expires_from_now(seconds(5)) > 0)
 102  *   {
 103  *     // We managed to cancel the timer. Start new asynchronous wait.
 104  *     my_timer.async_wait(on_timeout);
 105  *   }
 106  *   else
 107  *   {
 108  *     // Too late, timer has already expired!
 109  *   }
 110  * }
 111  *
 112  * void on_timeout(const boost::system::error_code& e)
 113  * {
 114  *   if (e != boost::asio::error::operation_aborted)
 115  *   {
 116  *     // Timer was not cancelled, take necessary action.
 117  *   }
 118  * }
 119  * @endcode
 120  *
 121  * @li The boost::asio::basic_deadline_timer::expires_from_now() function
 122  * cancels any pending asynchronous waits, and returns the number of
 123  * asynchronous waits that were cancelled. If it returns 0 then you were too
 124  * late and the wait handler has already been executed, or will soon be
 125  * executed. If it returns 1 then the wait handler was successfully cancelled.
 126  *
 127  * @li If a wait handler is cancelled, the boost::system::error_code passed to
 128  * it contains the value boost::asio::error::operation_aborted.
 129  */
 130 template <typename Time,
 131     typename TimeTraits = boost::asio::time_traits<Time>
 132     BOOST_ASIO_SVC_TPARAM_DEF2(= deadline_timer_service<Time, TimeTraits>)>
 133 class basic_deadline_timer
 134   : BOOST_ASIO_SVC_ACCESS basic_io_object<BOOST_ASIO_SVC_T>
 135 {
 136 public:
 137   /// The type of the executor associated with the object.
 138   typedef io_context::executor_type executor_type;
 139
 140   /// The time traits type.
 141   typedef TimeTraits traits_type;
 142
 143   /// The time type.
 144   typedef typename traits_type::time_type time_type;
 145
 146   /// The duration type.
 147   typedef typename traits_type::duration_type duration_type;
 148
 149   /// Constructor.
 150   /**
 151    * This constructor creates a timer without setting an expiry time. The
 152    * expires_at() or expires_from_now() functions must be called to set an
 153    * expiry time before the timer can be waited on.
 154    *
 155    * @param io_context The io_context object that the timer will use to dispatch
 156    * handlers for any asynchronous operations performed on the timer.
 157    */
 158   explicit basic_deadline_timer(boost::asio::io_context& io_context)
 159     : basic_io_object<BOOST_ASIO_SVC_T>(io_context)
 160   {
 161   }
 162
 163   /// Constructor to set a particular expiry time as an absolute time.
 164   /**
 165    * This constructor creates a timer and sets the expiry time.
 166    *
 167    * @param io_context The io_context object that the timer will use to dispatch
 168    * handlers for any asynchronous operations performed on the timer.
 169    *
 170    * @param expiry_time The expiry time to be used for the timer, expressed
 171    * as an absolute time.
 172    */
 173   basic_deadline_timer(boost::asio::io_context& io_context,
 174       const time_type& expiry_time)
 175     : basic_io_object<BOOST_ASIO_SVC_T>(io_context)
 176   {
 177     boost::system::error_code ec;
 178     this->get_service().expires_at(this->get_implementation(), expiry_time, ec);
 179     boost::asio::detail::throw_error(ec, "expires_at");
 180   }
 181
 182   /// Constructor to set a particular expiry time relative to now.
 183   /**
 184    * This constructor creates a timer and sets the expiry time.
 185    *
 186    * @param io_context The io_context object that the timer will use to dispatch
 187    * handlers for any asynchronous operations performed on the timer.
 188    *
 189    * @param expiry_time The expiry time to be used for the timer, relative to
 190    * now.
 191    */
 192   basic_deadline_timer(boost::asio::io_context& io_context,
 193       const duration_type& expiry_time)
 194     : basic_io_object<BOOST_ASIO_SVC_T>(io_context)
 195   {
 196     boost::system::error_code ec;
 197     this->get_service().expires_from_now(
 198         this->get_implementation(), expiry_time, ec);
 199     boost::asio::detail::throw_error(ec, "expires_from_now");
 200   }
 201
 202 #if defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
 203   /// Move-construct a basic_deadline_timer from another.
 204   /**
 205    * This constructor moves a timer from one object to another.
 206    *
 207    * @param other The other basic_deadline_timer object from which the move will
 208    * occur.
 209    *
 210    * @note Following the move, the moved-from object is in the same state as if
 211    * constructed using the @c basic_deadline_timer(io_context&) constructor.
 212    */
 213   basic_deadline_timer(basic_deadline_timer&& other)
 214     : basic_io_object<BOOST_ASIO_SVC_T>(std::move(other))
 215   {
 216   }
 217
 218   /// Move-assign a basic_deadline_timer from another.
 219   /**
 220    * This assignment operator moves a timer from one object to another. Cancels
 221    * any outstanding asynchronous operations associated with the target object.
 222    *
 223    * @param other The other basic_deadline_timer object from which the move will
 224    * occur.
 225    *
 226    * @note Following the move, the moved-from object is in the same state as if
 227    * constructed using the @c basic_deadline_timer(io_context&) constructor.
 228    */
 229   basic_deadline_timer& operator=(basic_deadline_timer&& other)
 230   {
 231     basic_io_object<BOOST_ASIO_SVC_T>::operator=(std::move(other));
 232     return *this;
 233   }
 234 #endif // defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
 235
 236   /// Destroys the timer.
 237   /**
 238    * This function destroys the timer, cancelling any outstanding asynchronous
 239    * wait operations associated with the timer as if by calling @c cancel.
 240    */
 241   ~basic_deadline_timer()
 242   {
 243   }
 244
 245 #if defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 246   // These functions are provided by basic_io_object<>.
 247 #else // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 248 #if !defined(BOOST_ASIO_NO_DEPRECATED)
 249   /// (Deprecated: Use get_executor().) Get the io_context associated with the
 250   /// object.
 251   /**
 252    * This function may be used to obtain the io_context object that the I/O
 253    * object uses to dispatch handlers for asynchronous operations.
 254    *
 255    * @return A reference to the io_context object that the I/O object will use
 256    * to dispatch handlers. Ownership is not transferred to the caller.
 257    */
 258   boost::asio::io_context& get_io_context()
 259   {
 260     return basic_io_object<BOOST_ASIO_SVC_T>::get_io_context();
 261   }
 262
 263   /// (Deprecated: Use get_executor().) Get the io_context associated with the
 264   /// object.
 265   /**
 266    * This function may be used to obtain the io_context object that the I/O
 267    * object uses to dispatch handlers for asynchronous operations.
 268    *
 269    * @return A reference to the io_context object that the I/O object will use
 270    * to dispatch handlers. Ownership is not transferred to the caller.
 271    */
 272   boost::asio::io_context& get_io_service()
 273   {
 274     return basic_io_object<BOOST_ASIO_SVC_T>::get_io_service();
 275   }
 276 #endif // !defined(BOOST_ASIO_NO_DEPRECATED)
 277
 278   /// Get the executor associated with the object.
 279   executor_type get_executor() BOOST_ASIO_NOEXCEPT
 280   {
 281     return basic_io_object<BOOST_ASIO_SVC_T>::get_executor();
 282   }
 283 #endif // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 284
 285   /// Cancel any asynchronous operations that are waiting on the timer.
 286   /**
 287    * This function forces the completion of any pending asynchronous wait
 288    * operations against the timer. The handler for each cancelled operation will
 289    * be invoked with the boost::asio::error::operation_aborted error code.
 290    *
 291    * Cancelling the timer does not change the expiry time.
 292    *
 293    * @return The number of asynchronous operations that were cancelled.
 294    *
 295    * @throws boost::system::system_error Thrown on failure.
 296    *
 297    * @note If the timer has already expired when cancel() is called, then the
 298    * handlers for asynchronous wait operations will:
 299    *
 300    * @li have already been invoked; or
 301    *
 302    * @li have been queued for invocation in the near future.
 303    *
 304    * These handlers can no longer be cancelled, and therefore are passed an
 305    * error code that indicates the successful completion of the wait operation.
 306    */
 307   std::size_t cancel()
 308   {
 309     boost::system::error_code ec;
 310     std::size_t s = this->get_service().cancel(this->get_implementation(), ec);
 311     boost::asio::detail::throw_error(ec, "cancel");
 312     return s;
 313   }
 314
 315   /// Cancel any asynchronous operations that are waiting on the timer.
 316   /**
 317    * This function forces the completion of any pending asynchronous wait
 318    * operations against the timer. The handler for each cancelled operation will
 319    * be invoked with the boost::asio::error::operation_aborted error code.
 320    *
 321    * Cancelling the timer does not change the expiry time.
 322    *
 323    * @param ec Set to indicate what error occurred, if any.
 324    *
 325    * @return The number of asynchronous operations that were cancelled.
 326    *
 327    * @note If the timer has already expired when cancel() is called, then the
 328    * handlers for asynchronous wait operations will:
 329    *
 330    * @li have already been invoked; or
 331    *
 332    * @li have been queued for invocation in the near future.
 333    *
 334    * These handlers can no longer be cancelled, and therefore are passed an
 335    * error code that indicates the successful completion of the wait operation.
 336    */
 337   std::size_t cancel(boost::system::error_code& ec)
 338   {
 339     return this->get_service().cancel(this->get_implementation(), ec);
 340   }
 341
 342   /// Cancels one asynchronous operation that is waiting on the timer.
 343   /**
 344    * This function forces the completion of one pending asynchronous wait
 345    * operation against the timer. Handlers are cancelled in FIFO order. The
 346    * handler for the cancelled operation will be invoked with the
 347    * boost::asio::error::operation_aborted error code.
 348    *
 349    * Cancelling the timer does not change the expiry time.
 350    *
 351    * @return The number of asynchronous operations that were cancelled. That is,
 352    * either 0 or 1.
 353    *
 354    * @throws boost::system::system_error Thrown on failure.
 355    *
 356    * @note If the timer has already expired when cancel_one() is called, then
 357    * the handlers for asynchronous wait operations will:
 358    *
 359    * @li have already been invoked; or
 360    *
 361    * @li have been queued for invocation in the near future.
 362    *
 363    * These handlers can no longer be cancelled, and therefore are passed an
 364    * error code that indicates the successful completion of the wait operation.
 365    */
 366   std::size_t cancel_one()
 367   {
 368     boost::system::error_code ec;
 369     std::size_t s = this->get_service().cancel_one(
 370         this->get_implementation(), ec);
 371     boost::asio::detail::throw_error(ec, "cancel_one");
 372     return s;
 373   }
 374
 375   /// Cancels one asynchronous operation that is waiting on the timer.
 376   /**
 377    * This function forces the completion of one pending asynchronous wait
 378    * operation against the timer. Handlers are cancelled in FIFO order. The
 379    * handler for the cancelled operation will be invoked with the
 380    * boost::asio::error::operation_aborted error code.
 381    *
 382    * Cancelling the timer does not change the expiry time.
 383    *
 384    * @param ec Set to indicate what error occurred, if any.
 385    *
 386    * @return The number of asynchronous operations that were cancelled. That is,
 387    * either 0 or 1.
 388    *
 389    * @note If the timer has already expired when cancel_one() is called, then
 390    * the handlers for asynchronous wait operations will:
 391    *
 392    * @li have already been invoked; or
 393    *
 394    * @li have been queued for invocation in the near future.
 395    *
 396    * These handlers can no longer be cancelled, and therefore are passed an
 397    * error code that indicates the successful completion of the wait operation.
 398    */
 399   std::size_t cancel_one(boost::system::error_code& ec)
 400   {
 401     return this->get_service().cancel_one(this->get_implementation(), ec);
 402   }
 403
 404   /// Get the timer's expiry time as an absolute time.
 405   /**
 406    * This function may be used to obtain the timer's current expiry time.
 407    * Whether the timer has expired or not does not affect this value.
 408    */
 409   time_type expires_at() const
 410   {
 411     return this->get_service().expires_at(this->get_implementation());
 412   }
 413
 414   /// Set the timer's expiry time as an absolute time.
 415   /**
 416    * This function sets the expiry time. Any pending asynchronous wait
 417    * operations will be cancelled. The handler for each cancelled operation will
 418    * be invoked with the boost::asio::error::operation_aborted error code.
 419    *
 420    * @param expiry_time The expiry time to be used for the timer.
 421    *
 422    * @return The number of asynchronous operations that were cancelled.
 423    *
 424    * @throws boost::system::system_error Thrown on failure.
 425    *
 426    * @note If the timer has already expired when expires_at() is called, then
 427    * the handlers for asynchronous wait operations will:
 428    *
 429    * @li have already been invoked; or
 430    *
 431    * @li have been queued for invocation in the near future.
 432    *
 433    * These handlers can no longer be cancelled, and therefore are passed an
 434    * error code that indicates the successful completion of the wait operation.
 435    */
 436   std::size_t expires_at(const time_type& expiry_time)
 437   {
 438     boost::system::error_code ec;
 439     std::size_t s = this->get_service().expires_at(
 440         this->get_implementation(), expiry_time, ec);
 441     boost::asio::detail::throw_error(ec, "expires_at");
 442     return s;
 443   }
 444
 445   /// Set the timer's expiry time as an absolute time.
 446   /**
 447    * This function sets the expiry time. Any pending asynchronous wait
 448    * operations will be cancelled. The handler for each cancelled operation will
 449    * be invoked with the boost::asio::error::operation_aborted error code.
 450    *
 451    * @param expiry_time The expiry time to be used for the timer.
 452    *
 453    * @param ec Set to indicate what error occurred, if any.
 454    *
 455    * @return The number of asynchronous operations that were cancelled.
 456    *
 457    * @note If the timer has already expired when expires_at() is called, then
 458    * the handlers for asynchronous wait operations will:
 459    *
 460    * @li have already been invoked; or
 461    *
 462    * @li have been queued for invocation in the near future.
 463    *
 464    * These handlers can no longer be cancelled, and therefore are passed an
 465    * error code that indicates the successful completion of the wait operation.
 466    */
 467   std::size_t expires_at(const time_type& expiry_time,
 468       boost::system::error_code& ec)
 469   {
 470     return this->get_service().expires_at(
 471         this->get_implementation(), expiry_time, ec);
 472   }
 473
 474   /// Get the timer's expiry time relative to now.
 475   /**
 476    * This function may be used to obtain the timer's current expiry time.
 477    * Whether the timer has expired or not does not affect this value.
 478    */
 479   duration_type expires_from_now() const
 480   {
 481     return this->get_service().expires_from_now(this->get_implementation());
 482   }
 483
 484   /// Set the timer's expiry time relative to now.
 485   /**
 486    * This function sets the expiry time. Any pending asynchronous wait
 487    * operations will be cancelled. The handler for each cancelled operation will
 488    * be invoked with the boost::asio::error::operation_aborted error code.
 489    *
 490    * @param expiry_time The expiry time to be used for the timer.
 491    *
 492    * @return The number of asynchronous operations that were cancelled.
 493    *
 494    * @throws boost::system::system_error Thrown on failure.
 495    *
 496    * @note If the timer has already expired when expires_from_now() is called,
 497    * then the handlers for asynchronous wait operations will:
 498    *
 499    * @li have already been invoked; or
 500    *
 501    * @li have been queued for invocation in the near future.
 502    *
 503    * These handlers can no longer be cancelled, and therefore are passed an
 504    * error code that indicates the successful completion of the wait operation.
 505    */
 506   std::size_t expires_from_now(const duration_type& expiry_time)
 507   {
 508     boost::system::error_code ec;
 509     std::size_t s = this->get_service().expires_from_now(
 510         this->get_implementation(), expiry_time, ec);
 511     boost::asio::detail::throw_error(ec, "expires_from_now");
 512     return s;
 513   }
 514
 515   /// Set the timer's expiry time relative to now.
 516   /**
 517    * This function sets the expiry time. Any pending asynchronous wait
 518    * operations will be cancelled. The handler for each cancelled operation will
 519    * be invoked with the boost::asio::error::operation_aborted error code.
 520    *
 521    * @param expiry_time The expiry time to be used for the timer.
 522    *
 523    * @param ec Set to indicate what error occurred, if any.
 524    *
 525    * @return The number of asynchronous operations that were cancelled.
 526    *
 527    * @note If the timer has already expired when expires_from_now() is called,
 528    * then the handlers for asynchronous wait operations will:
 529    *
 530    * @li have already been invoked; or
 531    *
 532    * @li have been queued for invocation in the near future.
 533    *
 534    * These handlers can no longer be cancelled, and therefore are passed an
 535    * error code that indicates the successful completion of the wait operation.
 536    */
 537   std::size_t expires_from_now(const duration_type& expiry_time,
 538       boost::system::error_code& ec)
 539   {
 540     return this->get_service().expires_from_now(
 541         this->get_implementation(), expiry_time, ec);
 542   }
 543
 544   /// Perform a blocking wait on the timer.
 545   /**
 546    * This function is used to wait for the timer to expire. This function
 547    * blocks and does not return until the timer has expired.
 548    *
 549    * @throws boost::system::system_error Thrown on failure.
 550    */
 551   void wait()
 552   {
 553     boost::system::error_code ec;
 554     this->get_service().wait(this->get_implementation(), ec);
 555     boost::asio::detail::throw_error(ec, "wait");
 556   }
 557
 558   /// Perform a blocking wait on the timer.
 559   /**
 560    * This function is used to wait for the timer to expire. This function
 561    * blocks and does not return until the timer has expired.
 562    *
 563    * @param ec Set to indicate what error occurred, if any.
 564    */
 565   void wait(boost::system::error_code& ec)
 566   {
 567     this->get_service().wait(this->get_implementation(), ec);
 568   }
 569
 570   /// Start an asynchronous wait on the timer.
 571   /**
 572    * This function may be used to initiate an asynchronous wait against the
 573    * timer. It always returns immediately.
 574    *
 575    * For each call to async_wait(), the supplied handler will be called exactly
 576    * once. The handler will be called when:
 577    *
 578    * @li The timer has expired.
 579    *
 580    * @li The timer was cancelled, in which case the handler is passed the error
 581    * code boost::asio::error::operation_aborted.
 582    *
 583    * @param handler The handler to be called when the timer expires. Copies
 584    * will be made of the handler as required. The function signature of the
 585    * handler must be:
 586    * @code void handler(
 587    *   const boost::system::error_code& error // Result of operation.
 588    * ); @endcode
 589    * Regardless of whether the asynchronous operation completes immediately or
 590    * not, the handler will not be invoked from within this function. Invocation
 591    * of the handler will be performed in a manner equivalent to using
 592    * boost::asio::io_context::post().
 593    */
 594   template <typename WaitHandler>
 595   BOOST_ASIO_INITFN_RESULT_TYPE(WaitHandler,
 596       void (boost::system::error_code))
 597   async_wait(BOOST_ASIO_MOVE_ARG(WaitHandler) handler)
 598   {
 599     // If you get an error on the following line it means that your handler does
 600     // not meet the documented type requirements for a WaitHandler.
 601     BOOST_ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
 602
 603 #if defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 604     return this->get_service().async_wait(this->get_implementation(),
 605         BOOST_ASIO_MOVE_CAST(WaitHandler)(handler));
 606 #else // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 607     async_completion<WaitHandler,
 608       void (boost::system::error_code)> init(handler);
 609
 610     this->get_service().async_wait(this->get_implementation(),
 611         init.completion_handler);
 612
 613     return init.result.get();
 614 #endif // defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 615   }
 616 };
 617
 618 } // namespace asio
 619 } // namespace boost
 620
 621 #include <boost/asio/detail/pop_options.hpp>
 622
 623 #if !defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 624 # undef BOOST_ASIO_SVC_T
 625 #endif // !defined(BOOST_ASIO_ENABLE_OLD_SERVICES)
 626
 627 #endif // defined(BOOST_ASIO_HAS_BOOST_DATE_TIME)
 628        // || defined(GENERATING_DOCUMENTATION)
 629
 630 #endif // BOOST_ASIO_BASIC_DEADLINE_TIMER_HPP