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Diffstat (limited to 'src/lib/asiolink/interval_timer.cc')
| -rw-r--r-- | src/lib/asiolink/interval_timer.cc | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/lib/asiolink/interval_timer.cc b/src/lib/asiolink/interval_timer.cc new file mode 100644 index 0000000..2cda9b0 --- /dev/null +++ b/src/lib/asiolink/interval_timer.cc @@ -0,0 +1,201 @@ +// Copyright (C) 2011-2020 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#include <config.h> +#include <asiolink/asio_wrapper.h> +#include <asiolink/interval_timer.h> +#include <asiolink/io_service.h> + +#include <boost/enable_shared_from_this.hpp> +#include <boost/noncopyable.hpp> +#include <boost/shared_ptr.hpp> + +#include <exceptions/exceptions.h> + +#include <atomic> +#include <functional> +#include <mutex> + +using namespace std; +namespace ph = std::placeholders; + +namespace isc { +namespace asiolink { + +/// This class holds a call back function of asynchronous operations. +/// To ensure the object is alive while an asynchronous operation refers +/// to it, we use shared_ptr and enable_shared_from_this. +/// The object will be destructed in case IntervalTimer has been destructed +/// and no asynchronous operation refers to it. +/// Please follow the link to get an example: +/// http://think-async.com/asio/asio-1.4.8/doc/asio/tutorial/tutdaytime3.html#asio.tutorial.tutdaytime3.the_tcp_connection_class +class IntervalTimerImpl : + public boost::enable_shared_from_this<IntervalTimerImpl>, + public boost::noncopyable { +public: + + /// @brief Constructor. + /// + /// @param io_service The IO service used to handle events. + IntervalTimerImpl(IOService& io_service); + + /// @brief Destructor. + ~IntervalTimerImpl(); + + /// @brief Setup function to register callback and start timer. + /// + /// @param cbfunc The callback function registered on timer. + /// @param interval The interval used to start the timer. + /// @param interval_mode The interval mode used by the timer. + void setup(const IntervalTimer::Callback& cbfunc, const long interval, + const IntervalTimer::Mode& interval_mode + = IntervalTimer::REPEATING); + + /// @brief Callback function which calls the registerd callback. + /// + /// @param error The error code retrieved from the timer. + void callback(const boost::system::error_code& error); + + /// @brief Cancel timer. + void cancel() { + lock_guard<mutex> lk (mutex_); + timer_.cancel(); + interval_ = 0; + } + + /// @brief Get the timer interval. + /// + /// @return The timer interval. + long getInterval() const { return (interval_); } + +private: + + /// @brief Update function to update timer_ when it expires. + /// + /// Should be called in a thread safe context. + void update(); + + /// @brief The callback function to call when timer_ expires. + IntervalTimer::Callback cbfunc_; + + /// @brief The interval in milliseconds. + std::atomic<long> interval_; + + /// @brief The asio timer. + boost::asio::deadline_timer timer_; + + /// @brief Controls how the timer behaves after expiration. + IntervalTimer::Mode mode_; + + /// @brief Mutex to protect the internal state. + std::mutex mutex_; + + /// @brief Invalid interval value. + /// + /// @ref interval_ will be set to this value in destructor in order to + /// detect use-after-free type of bugs. + static const long INVALIDATED_INTERVAL = -1; +}; + +IntervalTimerImpl::IntervalTimerImpl(IOService& io_service) : + interval_(0), timer_(io_service.get_io_service()), + mode_(IntervalTimer::REPEATING) { +} + +IntervalTimerImpl::~IntervalTimerImpl() { + interval_ = INVALIDATED_INTERVAL; +} + +void +IntervalTimerImpl::setup(const IntervalTimer::Callback& cbfunc, + const long interval, + const IntervalTimer::Mode& mode) { + // Interval should not be less than 0. + if (interval < 0) { + isc_throw(isc::BadValue, "Interval should not be less than or " + "equal to 0"); + } + // Call back function should not be empty. + if (!cbfunc) { + isc_throw(isc::InvalidParameter, "Callback function is empty"); + } + + lock_guard<mutex> lk(mutex_); + cbfunc_ = cbfunc; + interval_ = interval; + mode_ = mode; + + // Set initial expire time. + // At this point the timer is not running yet and will not expire. + // After calling IOService::run(), the timer will expire. + update(); +} + +void +IntervalTimerImpl::update() { + try { + // Update expire time to (current time + interval_). + timer_.expires_from_now(boost::posix_time::millisec(long(interval_))); + // Reset timer. + // Pass a function bound with a shared_ptr to this. + timer_.async_wait(std::bind(&IntervalTimerImpl::callback, + shared_from_this(), + ph::_1)); //error + } catch (const boost::system::system_error& e) { + isc_throw(isc::Unexpected, "Failed to update timer: " << e.what()); + } catch (const boost::bad_weak_ptr&) { + // Can't happen. It means a severe internal bug. + } +} + +void +IntervalTimerImpl::callback(const boost::system::error_code& ec) { + if (interval_ == INVALIDATED_INTERVAL) { + isc_throw(isc::BadValue, "Interval internal state"); + } + if (interval_ == 0 || ec) { + // timer has been canceled. Do nothing. + } else { + { + lock_guard<mutex> lk(mutex_); + // If we should repeat, set next expire time. + if (mode_ == IntervalTimer::REPEATING) { + update(); + } + } + + // Invoke the call back function. + cbfunc_(); + } +} + +IntervalTimer::IntervalTimer(IOService& io_service) : + impl_(new IntervalTimerImpl(io_service)) { +} + +IntervalTimer::~IntervalTimer() { + // Cancel the timer to make sure cbfunc_() will not be called any more. + cancel(); +} + +void +IntervalTimer::setup(const Callback& cbfunc, const long interval, + const IntervalTimer::Mode& mode) { + return (impl_->setup(cbfunc, interval, mode)); +} + +void +IntervalTimer::cancel() { + impl_->cancel(); +} + +long +IntervalTimer::getInterval() const { + return (impl_->getInterval()); +} + +} // namespace asiolink +} // namespace isc |