| // |
| // basic_waitable_timer.hpp |
| // ~~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2014 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #ifndef ASIO_BASIC_WAITABLE_TIMER_HPP |
| #define ASIO_BASIC_WAITABLE_TIMER_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/config.hpp" |
| #include <cstddef> |
| #include "asio/basic_io_object.hpp" |
| #include "asio/detail/handler_type_requirements.hpp" |
| #include "asio/detail/throw_error.hpp" |
| #include "asio/error.hpp" |
| #include "asio/wait_traits.hpp" |
| #include "asio/waitable_timer_service.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| namespace asio { |
| |
| /// Provides waitable timer functionality. |
| /** |
| * The basic_waitable_timer class template provides the ability to perform a |
| * blocking or asynchronous wait for a timer to expire. |
| * |
| * A waitable timer is always in one of two states: "expired" or "not expired". |
| * If the wait() or async_wait() function is called on an expired timer, the |
| * wait operation will complete immediately. |
| * |
| * Most applications will use one of the asio::steady_timer, |
| * asio::system_timer or asio::high_resolution_timer typedefs. |
| * |
| * @note This waitable timer functionality is for use with the C++11 standard |
| * library's @c <chrono> facility, or with the Boost.Chrono library. |
| * |
| * @par Thread Safety |
| * @e Distinct @e objects: Safe.@n |
| * @e Shared @e objects: Unsafe. |
| * |
| * @par Examples |
| * Performing a blocking wait (C++11): |
| * @code |
| * // Construct a timer without setting an expiry time. |
| * asio::steady_timer timer(io_service); |
| * |
| * // Set an expiry time relative to now. |
| * timer.expires_from_now(std::chrono::seconds(5)); |
| * |
| * // Wait for the timer to expire. |
| * timer.wait(); |
| * @endcode |
| * |
| * @par |
| * Performing an asynchronous wait (C++11): |
| * @code |
| * void handler(const asio::error_code& error) |
| * { |
| * if (!error) |
| * { |
| * // Timer expired. |
| * } |
| * } |
| * |
| * ... |
| * |
| * // Construct a timer with an absolute expiry time. |
| * asio::steady_timer timer(io_service, |
| * std::chrono::steady_clock::now() + std::chrono::seconds(60)); |
| * |
| * // Start an asynchronous wait. |
| * timer.async_wait(handler); |
| * @endcode |
| * |
| * @par Changing an active waitable timer's expiry time |
| * |
| * Changing the expiry time of a timer while there are pending asynchronous |
| * waits causes those wait operations to be cancelled. To ensure that the action |
| * associated with the timer is performed only once, use something like this: |
| * used: |
| * |
| * @code |
| * void on_some_event() |
| * { |
| * if (my_timer.expires_from_now(seconds(5)) > 0) |
| * { |
| * // We managed to cancel the timer. Start new asynchronous wait. |
| * my_timer.async_wait(on_timeout); |
| * } |
| * else |
| * { |
| * // Too late, timer has already expired! |
| * } |
| * } |
| * |
| * void on_timeout(const asio::error_code& e) |
| * { |
| * if (e != asio::error::operation_aborted) |
| * { |
| * // Timer was not cancelled, take necessary action. |
| * } |
| * } |
| * @endcode |
| * |
| * @li The asio::basic_waitable_timer::expires_from_now() function |
| * cancels any pending asynchronous waits, and returns the number of |
| * asynchronous waits that were cancelled. If it returns 0 then you were too |
| * late and the wait handler has already been executed, or will soon be |
| * executed. If it returns 1 then the wait handler was successfully cancelled. |
| * |
| * @li If a wait handler is cancelled, the asio::error_code passed to |
| * it contains the value asio::error::operation_aborted. |
| */ |
| template <typename Clock, |
| typename WaitTraits = asio::wait_traits<Clock>, |
| typename WaitableTimerService = waitable_timer_service<Clock, WaitTraits> > |
| class basic_waitable_timer |
| : public basic_io_object<WaitableTimerService> |
| { |
| public: |
| /// The clock type. |
| typedef Clock clock_type; |
| |
| /// The duration type of the clock. |
| typedef typename clock_type::duration duration; |
| |
| /// The time point type of the clock. |
| typedef typename clock_type::time_point time_point; |
| |
| /// The wait traits type. |
| typedef WaitTraits traits_type; |
| |
| /// Constructor. |
| /** |
| * This constructor creates a timer without setting an expiry time. The |
| * expires_at() or expires_from_now() functions must be called to set an |
| * expiry time before the timer can be waited on. |
| * |
| * @param io_service The io_service object that the timer will use to dispatch |
| * handlers for any asynchronous operations performed on the timer. |
| */ |
| explicit basic_waitable_timer(asio::io_service& io_service) |
| : basic_io_object<WaitableTimerService>(io_service) |
| { |
| } |
| |
| /// Constructor to set a particular expiry time as an absolute time. |
| /** |
| * This constructor creates a timer and sets the expiry time. |
| * |
| * @param io_service The io_service object that the timer will use to dispatch |
| * handlers for any asynchronous operations performed on the timer. |
| * |
| * @param expiry_time The expiry time to be used for the timer, expressed |
| * as an absolute time. |
| */ |
| basic_waitable_timer(asio::io_service& io_service, |
| const time_point& expiry_time) |
| : basic_io_object<WaitableTimerService>(io_service) |
| { |
| asio::error_code ec; |
| this->service.expires_at(this->implementation, expiry_time, ec); |
| asio::detail::throw_error(ec, "expires_at"); |
| } |
| |
| /// Constructor to set a particular expiry time relative to now. |
| /** |
| * This constructor creates a timer and sets the expiry time. |
| * |
| * @param io_service The io_service object that the timer will use to dispatch |
| * handlers for any asynchronous operations performed on the timer. |
| * |
| * @param expiry_time The expiry time to be used for the timer, relative to |
| * now. |
| */ |
| basic_waitable_timer(asio::io_service& io_service, |
| const duration& expiry_time) |
| : basic_io_object<WaitableTimerService>(io_service) |
| { |
| asio::error_code ec; |
| this->service.expires_from_now(this->implementation, expiry_time, ec); |
| asio::detail::throw_error(ec, "expires_from_now"); |
| } |
| |
| /// Cancel any asynchronous operations that are waiting on the timer. |
| /** |
| * This function forces the completion of any pending asynchronous wait |
| * operations against the timer. The handler for each cancelled operation will |
| * be invoked with the asio::error::operation_aborted error code. |
| * |
| * Cancelling the timer does not change the expiry time. |
| * |
| * @return The number of asynchronous operations that were cancelled. |
| * |
| * @throws asio::system_error Thrown on failure. |
| * |
| * @note If the timer has already expired when cancel() is called, then the |
| * handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t cancel() |
| { |
| asio::error_code ec; |
| std::size_t s = this->service.cancel(this->implementation, ec); |
| asio::detail::throw_error(ec, "cancel"); |
| return s; |
| } |
| |
| /// Cancel any asynchronous operations that are waiting on the timer. |
| /** |
| * This function forces the completion of any pending asynchronous wait |
| * operations against the timer. The handler for each cancelled operation will |
| * be invoked with the asio::error::operation_aborted error code. |
| * |
| * Cancelling the timer does not change the expiry time. |
| * |
| * @param ec Set to indicate what error occurred, if any. |
| * |
| * @return The number of asynchronous operations that were cancelled. |
| * |
| * @note If the timer has already expired when cancel() is called, then the |
| * handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t cancel(asio::error_code& ec) |
| { |
| return this->service.cancel(this->implementation, ec); |
| } |
| |
| /// Cancels one asynchronous operation that is waiting on the timer. |
| /** |
| * This function forces the completion of one pending asynchronous wait |
| * operation against the timer. Handlers are cancelled in FIFO order. The |
| * handler for the cancelled operation will be invoked with the |
| * asio::error::operation_aborted error code. |
| * |
| * Cancelling the timer does not change the expiry time. |
| * |
| * @return The number of asynchronous operations that were cancelled. That is, |
| * either 0 or 1. |
| * |
| * @throws asio::system_error Thrown on failure. |
| * |
| * @note If the timer has already expired when cancel_one() is called, then |
| * the handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t cancel_one() |
| { |
| asio::error_code ec; |
| std::size_t s = this->service.cancel_one(this->implementation, ec); |
| asio::detail::throw_error(ec, "cancel_one"); |
| return s; |
| } |
| |
| /// Cancels one asynchronous operation that is waiting on the timer. |
| /** |
| * This function forces the completion of one pending asynchronous wait |
| * operation against the timer. Handlers are cancelled in FIFO order. The |
| * handler for the cancelled operation will be invoked with the |
| * asio::error::operation_aborted error code. |
| * |
| * Cancelling the timer does not change the expiry time. |
| * |
| * @param ec Set to indicate what error occurred, if any. |
| * |
| * @return The number of asynchronous operations that were cancelled. That is, |
| * either 0 or 1. |
| * |
| * @note If the timer has already expired when cancel_one() is called, then |
| * the handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t cancel_one(asio::error_code& ec) |
| { |
| return this->service.cancel_one(this->implementation, ec); |
| } |
| |
| /// Get the timer's expiry time as an absolute time. |
| /** |
| * This function may be used to obtain the timer's current expiry time. |
| * Whether the timer has expired or not does not affect this value. |
| */ |
| time_point expires_at() const |
| { |
| return this->service.expires_at(this->implementation); |
| } |
| |
| /// Set the timer's expiry time as an absolute time. |
| /** |
| * This function sets the expiry time. Any pending asynchronous wait |
| * operations will be cancelled. The handler for each cancelled operation will |
| * be invoked with the asio::error::operation_aborted error code. |
| * |
| * @param expiry_time The expiry time to be used for the timer. |
| * |
| * @return The number of asynchronous operations that were cancelled. |
| * |
| * @throws asio::system_error Thrown on failure. |
| * |
| * @note If the timer has already expired when expires_at() is called, then |
| * the handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t expires_at(const time_point& expiry_time) |
| { |
| asio::error_code ec; |
| std::size_t s = this->service.expires_at( |
| this->implementation, expiry_time, ec); |
| asio::detail::throw_error(ec, "expires_at"); |
| return s; |
| } |
| |
| /// Set the timer's expiry time as an absolute time. |
| /** |
| * This function sets the expiry time. Any pending asynchronous wait |
| * operations will be cancelled. The handler for each cancelled operation will |
| * be invoked with the asio::error::operation_aborted error code. |
| * |
| * @param expiry_time The expiry time to be used for the timer. |
| * |
| * @param ec Set to indicate what error occurred, if any. |
| * |
| * @return The number of asynchronous operations that were cancelled. |
| * |
| * @note If the timer has already expired when expires_at() is called, then |
| * the handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t expires_at(const time_point& expiry_time, |
| asio::error_code& ec) |
| { |
| return this->service.expires_at(this->implementation, expiry_time, ec); |
| } |
| |
| /// Get the timer's expiry time relative to now. |
| /** |
| * This function may be used to obtain the timer's current expiry time. |
| * Whether the timer has expired or not does not affect this value. |
| */ |
| duration expires_from_now() const |
| { |
| return this->service.expires_from_now(this->implementation); |
| } |
| |
| /// Set the timer's expiry time relative to now. |
| /** |
| * This function sets the expiry time. Any pending asynchronous wait |
| * operations will be cancelled. The handler for each cancelled operation will |
| * be invoked with the asio::error::operation_aborted error code. |
| * |
| * @param expiry_time The expiry time to be used for the timer. |
| * |
| * @return The number of asynchronous operations that were cancelled. |
| * |
| * @throws asio::system_error Thrown on failure. |
| * |
| * @note If the timer has already expired when expires_from_now() is called, |
| * then the handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t expires_from_now(const duration& expiry_time) |
| { |
| asio::error_code ec; |
| std::size_t s = this->service.expires_from_now( |
| this->implementation, expiry_time, ec); |
| asio::detail::throw_error(ec, "expires_from_now"); |
| return s; |
| } |
| |
| /// Set the timer's expiry time relative to now. |
| /** |
| * This function sets the expiry time. Any pending asynchronous wait |
| * operations will be cancelled. The handler for each cancelled operation will |
| * be invoked with the asio::error::operation_aborted error code. |
| * |
| * @param expiry_time The expiry time to be used for the timer. |
| * |
| * @param ec Set to indicate what error occurred, if any. |
| * |
| * @return The number of asynchronous operations that were cancelled. |
| * |
| * @note If the timer has already expired when expires_from_now() is called, |
| * then the handlers for asynchronous wait operations will: |
| * |
| * @li have already been invoked; or |
| * |
| * @li have been queued for invocation in the near future. |
| * |
| * These handlers can no longer be cancelled, and therefore are passed an |
| * error code that indicates the successful completion of the wait operation. |
| */ |
| std::size_t expires_from_now(const duration& expiry_time, |
| asio::error_code& ec) |
| { |
| return this->service.expires_from_now( |
| this->implementation, expiry_time, ec); |
| } |
| |
| /// Perform a blocking wait on the timer. |
| /** |
| * This function is used to wait for the timer to expire. This function |
| * blocks and does not return until the timer has expired. |
| * |
| * @throws asio::system_error Thrown on failure. |
| */ |
| void wait() |
| { |
| asio::error_code ec; |
| this->service.wait(this->implementation, ec); |
| asio::detail::throw_error(ec, "wait"); |
| } |
| |
| /// Perform a blocking wait on the timer. |
| /** |
| * This function is used to wait for the timer to expire. This function |
| * blocks and does not return until the timer has expired. |
| * |
| * @param ec Set to indicate what error occurred, if any. |
| */ |
| void wait(asio::error_code& ec) |
| { |
| this->service.wait(this->implementation, ec); |
| } |
| |
| /// Start an asynchronous wait on the timer. |
| /** |
| * This function may be used to initiate an asynchronous wait against the |
| * timer. It always returns immediately. |
| * |
| * For each call to async_wait(), the supplied handler will be called exactly |
| * once. The handler will be called when: |
| * |
| * @li The timer has expired. |
| * |
| * @li The timer was cancelled, in which case the handler is passed the error |
| * code asio::error::operation_aborted. |
| * |
| * @param handler The handler to be called when the timer expires. Copies |
| * will be made of the handler as required. The function signature of the |
| * handler must be: |
| * @code void handler( |
| * const asio::error_code& error // Result of operation. |
| * ); @endcode |
| * Regardless of whether the asynchronous operation completes immediately or |
| * not, the handler will not be invoked from within this function. Invocation |
| * of the handler will be performed in a manner equivalent to using |
| * asio::io_service::post(). |
| */ |
| template <typename WaitHandler> |
| ASIO_INITFN_RESULT_TYPE(WaitHandler, |
| void (asio::error_code)) |
| async_wait(ASIO_MOVE_ARG(WaitHandler) handler) |
| { |
| // If you get an error on the following line it means that your handler does |
| // not meet the documented type requirements for a WaitHandler. |
| ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check; |
| |
| return this->service.async_wait(this->implementation, |
| ASIO_MOVE_CAST(WaitHandler)(handler)); |
| } |
| }; |
| |
| } // namespace asio |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #endif // ASIO_BASIC_WAITABLE_TIMER_HPP |