382 lines
12 KiB
C++
382 lines
12 KiB
C++
//
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// basic_deadline_timer.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_BASIC_DEADLINE_TIMER_HPP
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#define ASIO_BASIC_DEADLINE_TIMER_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/push_options.hpp"
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#include "asio/detail/push_options.hpp"
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#include <cstddef>
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#include <boost/config.hpp>
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#include "asio/detail/pop_options.hpp"
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#include "asio/basic_io_object.hpp"
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#include "asio/deadline_timer_service.hpp"
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#include "asio/error.hpp"
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#include "asio/detail/throw_error.hpp"
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namespace asio {
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/// Provides waitable timer functionality.
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/**
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* The basic_deadline_timer class template provides the ability to perform a
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* blocking or asynchronous wait for a timer to expire.
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*
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* Most applications will use the asio::deadline_timer typedef.
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*
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* @par Thread Safety
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* @e Distinct @e objects: Safe.@n
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* @e Shared @e objects: Unsafe.
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*
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* @par Examples
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* Performing a blocking wait:
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* @code
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* // Construct a timer without setting an expiry time.
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* asio::deadline_timer timer(io_service);
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*
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* // Set an expiry time relative to now.
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* timer.expires_from_now(boost::posix_time::seconds(5));
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*
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* // Wait for the timer to expire.
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* timer.wait();
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* @endcode
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*
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* @par
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* Performing an asynchronous wait:
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* @code
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* void handler(const asio::error_code& error)
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* {
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* if (!error)
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* {
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* // Timer expired.
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* }
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* }
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*
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* ...
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*
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* // Construct a timer with an absolute expiry time.
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* asio::deadline_timer timer(io_service,
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* boost::posix_time::time_from_string("2005-12-07 23:59:59.000"));
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*
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* // Start an asynchronous wait.
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* timer.async_wait(handler);
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* @endcode
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*
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* @par Changing an active deadline_timer's expiry time
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*
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* Changing the expiry time of a timer while there are pending asynchronous
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* waits causes those wait operations to be cancelled. To ensure that the action
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* associated with the timer is performed only once, use something like this:
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* used:
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*
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* @code
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* void on_some_event()
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* {
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* if (my_timer.expires_from_now(seconds(5)) > 0)
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* {
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* // We managed to cancel the timer. Start new asynchronous wait.
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* my_timer.async_wait(on_timeout);
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* }
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* else
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* {
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* // Too late, timer has already expired!
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* }
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* }
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*
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* void on_timeout(const asio::error_code& e)
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* {
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* if (e != asio::error::operation_aborted)
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* {
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* // Timer was not cancelled, take necessary action.
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* }
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* }
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* @endcode
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*
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* @li The asio::basic_deadline_timer::expires_from_now() function
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* cancels any pending asynchronous waits, and returns the number of
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* asynchronous waits that were cancelled. If it returns 0 then you were too
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* late and the wait handler has already been executed, or will soon be
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* executed. If it returns 1 then the wait handler was successfully cancelled.
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*
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* @li If a wait handler is cancelled, the asio::error_code passed to
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* it contains the value asio::error::operation_aborted.
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*/
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template <typename Time,
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typename TimeTraits = asio::time_traits<Time>,
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typename TimerService = deadline_timer_service<Time, TimeTraits> >
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class basic_deadline_timer
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: public basic_io_object<TimerService>
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{
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public:
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/// The time traits type.
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typedef TimeTraits traits_type;
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/// The time type.
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typedef typename traits_type::time_type time_type;
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/// The duration type.
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typedef typename traits_type::duration_type duration_type;
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/// Constructor.
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/**
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* This constructor creates a timer without setting an expiry time. The
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* expires_at() or expires_from_now() functions must be called to set an
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* expiry time before the timer can be waited on.
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*
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* @param io_service The io_service object that the timer will use to dispatch
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* handlers for any asynchronous operations performed on the timer.
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*/
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explicit basic_deadline_timer(asio::io_service& io_service)
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: basic_io_object<TimerService>(io_service)
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{
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}
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/// Constructor to set a particular expiry time as an absolute time.
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/**
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* This constructor creates a timer and sets the expiry time.
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*
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* @param io_service The io_service object that the timer will use to dispatch
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* handlers for any asynchronous operations performed on the timer.
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*
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* @param expiry_time The expiry time to be used for the timer, expressed
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* as an absolute time.
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*/
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basic_deadline_timer(asio::io_service& io_service,
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const time_type& expiry_time)
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: basic_io_object<TimerService>(io_service)
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{
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asio::error_code ec;
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this->service.expires_at(this->implementation, expiry_time, ec);
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asio::detail::throw_error(ec);
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}
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/// Constructor to set a particular expiry time relative to now.
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/**
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* This constructor creates a timer and sets the expiry time.
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*
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* @param io_service The io_service object that the timer will use to dispatch
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* handlers for any asynchronous operations performed on the timer.
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*
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* @param expiry_time The expiry time to be used for the timer, relative to
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* now.
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*/
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basic_deadline_timer(asio::io_service& io_service,
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const duration_type& expiry_time)
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: basic_io_object<TimerService>(io_service)
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{
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asio::error_code ec;
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this->service.expires_from_now(this->implementation, expiry_time, ec);
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asio::detail::throw_error(ec);
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}
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/// Cancel any asynchronous operations that are waiting on the timer.
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/**
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* This function forces the completion of any pending asynchronous wait
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* operations against the timer. The handler for each cancelled operation will
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* be invoked with the asio::error::operation_aborted error code.
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*
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* Cancelling the timer does not change the expiry time.
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*
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* @return The number of asynchronous operations that were cancelled.
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*
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* @throws asio::system_error Thrown on failure.
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*/
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std::size_t cancel()
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{
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asio::error_code ec;
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std::size_t s = this->service.cancel(this->implementation, ec);
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asio::detail::throw_error(ec);
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return s;
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}
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/// Cancel any asynchronous operations that are waiting on the timer.
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/**
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* This function forces the completion of any pending asynchronous wait
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* operations against the timer. The handler for each cancelled operation will
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* be invoked with the asio::error::operation_aborted error code.
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*
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* Cancelling the timer does not change the expiry time.
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*
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* @param ec Set to indicate what error occurred, if any.
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*
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* @return The number of asynchronous operations that were cancelled.
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*/
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std::size_t cancel(asio::error_code& ec)
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{
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return this->service.cancel(this->implementation, ec);
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}
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/// Get the timer's expiry time as an absolute time.
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/**
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* This function may be used to obtain the timer's current expiry time.
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* Whether the timer has expired or not does not affect this value.
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*/
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time_type expires_at() const
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{
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return this->service.expires_at(this->implementation);
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}
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/// Set the timer's expiry time as an absolute time.
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/**
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* This function sets the expiry time. Any pending asynchronous wait
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* operations will be cancelled. The handler for each cancelled operation will
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* be invoked with the asio::error::operation_aborted error code.
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*
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* @param expiry_time The expiry time to be used for the timer.
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*
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* @return The number of asynchronous operations that were cancelled.
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*
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* @throws asio::system_error Thrown on failure.
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*/
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std::size_t expires_at(const time_type& expiry_time)
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{
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asio::error_code ec;
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std::size_t s = this->service.expires_at(
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this->implementation, expiry_time, ec);
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asio::detail::throw_error(ec);
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return s;
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}
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/// Set the timer's expiry time as an absolute time.
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/**
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* This function sets the expiry time. Any pending asynchronous wait
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* operations will be cancelled. The handler for each cancelled operation will
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* be invoked with the asio::error::operation_aborted error code.
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*
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* @param expiry_time The expiry time to be used for the timer.
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*
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* @param ec Set to indicate what error occurred, if any.
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*
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* @return The number of asynchronous operations that were cancelled.
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*/
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std::size_t expires_at(const time_type& expiry_time,
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asio::error_code& ec)
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{
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return this->service.expires_at(this->implementation, expiry_time, ec);
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}
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/// Get the timer's expiry time relative to now.
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/**
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* This function may be used to obtain the timer's current expiry time.
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* Whether the timer has expired or not does not affect this value.
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*/
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duration_type expires_from_now() const
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{
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return this->service.expires_from_now(this->implementation);
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}
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/// Set the timer's expiry time relative to now.
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/**
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* This function sets the expiry time. Any pending asynchronous wait
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* operations will be cancelled. The handler for each cancelled operation will
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* be invoked with the asio::error::operation_aborted error code.
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*
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* @param expiry_time The expiry time to be used for the timer.
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*
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* @return The number of asynchronous operations that were cancelled.
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*
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* @throws asio::system_error Thrown on failure.
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*/
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std::size_t expires_from_now(const duration_type& expiry_time)
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{
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asio::error_code ec;
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std::size_t s = this->service.expires_from_now(
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this->implementation, expiry_time, ec);
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asio::detail::throw_error(ec);
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return s;
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}
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/// Set the timer's expiry time relative to now.
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/**
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* This function sets the expiry time. Any pending asynchronous wait
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* operations will be cancelled. The handler for each cancelled operation will
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* be invoked with the asio::error::operation_aborted error code.
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*
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* @param expiry_time The expiry time to be used for the timer.
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*
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* @param ec Set to indicate what error occurred, if any.
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*
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* @return The number of asynchronous operations that were cancelled.
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*/
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std::size_t expires_from_now(const duration_type& expiry_time,
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asio::error_code& ec)
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{
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return this->service.expires_from_now(
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this->implementation, expiry_time, ec);
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}
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/// Perform a blocking wait on the timer.
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/**
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* This function is used to wait for the timer to expire. This function
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* blocks and does not return until the timer has expired.
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*
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* @throws asio::system_error Thrown on failure.
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*/
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void wait()
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{
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asio::error_code ec;
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this->service.wait(this->implementation, ec);
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asio::detail::throw_error(ec);
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}
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/// Perform a blocking wait on the timer.
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/**
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* This function is used to wait for the timer to expire. This function
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* blocks and does not return until the timer has expired.
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*
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* @param ec Set to indicate what error occurred, if any.
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*/
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void wait(asio::error_code& ec)
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{
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this->service.wait(this->implementation, ec);
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}
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/// Start an asynchronous wait on the timer.
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/**
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* This function may be used to initiate an asynchronous wait against the
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* timer. It always returns immediately.
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*
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* For each call to async_wait(), the supplied handler will be called exactly
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* once. The handler will be called when:
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*
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* @li The timer has expired.
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*
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* @li The timer was cancelled, in which case the handler is passed the error
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* code asio::error::operation_aborted.
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*
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* @param handler The handler to be called when the timer expires. Copies
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* will be made of the handler as required. The function signature of the
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* handler must be:
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* @code void handler(
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* const asio::error_code& error // Result of operation.
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* ); @endcode
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* Regardless of whether the asynchronous operation completes immediately or
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* not, the handler will not be invoked from within this function. Invocation
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* of the handler will be performed in a manner equivalent to using
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* asio::io_service::post().
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*/
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template <typename WaitHandler>
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void async_wait(WaitHandler handler)
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{
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this->service.async_wait(this->implementation, handler);
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}
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};
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#endif // ASIO_BASIC_DEADLINE_TIMER_HPP
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