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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* timer.cpp - Generic timer
*/
#include <libcamera/base/timer.h>
#include <chrono>
#include <libcamera/base/event_dispatcher.h>
#include <libcamera/base/log.h>
#include <libcamera/base/message.h>
#include <libcamera/base/thread.h>
#include <libcamera/base/utils.h>
#include <libcamera/camera_manager.h>
/**
* \file base/timer.h
* \brief Generic timer
*/
namespace libcamera {
LOG_DEFINE_CATEGORY(Timer)
/**
* \class Timer
* \brief Single-shot timer interface
*
* The Timer class models a single-shot timer that is started with start() and
* emits the \ref timeout signal when it times out.
*
* Once started the timer will run until it times out. It can be stopped with
* stop(), and once it times out or is stopped, can be started again with
* start().
*
* The timer deadline is specified as either a duration in milliseconds or an
* absolute time point. If the deadline is set to the current time or to the
* past, the timer will time out immediately when execution returns to the
* event loop of the timer's thread.
*
* Timers run in the thread they belong to, and thus emit the \a ref timeout
* signal from that thread. To avoid race conditions they must not be started
* or stopped from a different thread, attempts to do so will be rejected and
* logged, and may cause undefined behaviour.
*/
/**
* \brief Construct a timer
* \param[in] parent The parent Object
*/
Timer::Timer(Object *parent)
: Object(parent), running_(false)
{
}
Timer::~Timer()
{
stop();
}
/**
* \brief Start or restart the timer with a timeout of \a duration
* \param[in] duration The timer duration in milliseconds
*
* If the timer is already running it will be stopped and restarted.
*
* \context This function is \threadbound.
*/
void Timer::start(std::chrono::milliseconds duration)
{
start(utils::clock::now() + duration);
}
/**
* \brief Start or restart the timer with a \a deadline
* \param[in] deadline The timer deadline
*
* If the timer is already running it will be stopped and restarted.
*
* \context This function is \threadbound.
*/
void Timer::start(std::chrono::steady_clock::time_point deadline)
{
if (Thread::current() != thread()) {
LOG(Timer, Error) << "Timer " << this << " << can't be started from another thread";
return;
}
deadline_ = deadline;
LOG(Timer, Debug)
<< "Starting timer " << this << ": deadline "
<< utils::time_point_to_string(deadline_);
if (isRunning())
unregisterTimer();
registerTimer();
}
/**
* \brief Stop the timer
*
* After this function returns the timer is guaranteed not to emit the
* \ref timeout signal.
*
* If the timer is not running this function performs no operation.
*
* \context This function is \threadbound.
*/
void Timer::stop()
{
if (!isRunning())
return;
if (Thread::current() != thread()) {
LOG(Timer, Error) << "Timer " << this << " can't be stopped from another thread";
return;
}
unregisterTimer();
}
void Timer::registerTimer()
{
thread()->eventDispatcher()->registerTimer(this);
running_ = true;
}
void Timer::unregisterTimer()
{
running_ = false;
thread()->eventDispatcher()->unregisterTimer(this);
}
/**
* \brief Check if the timer is running
* \return True if the timer is running, false otherwise
*/
bool Timer::isRunning() const
{
return running_;
}
/**
* \fn Timer::deadline()
* \brief Retrieve the timer deadline
* \return The timer deadline
*/
/**
* \var Timer::timeout
* \brief Signal emitted when the timer times out
*
* The timer pointer is passed as a parameter.
*/
void Timer::message(Message *msg)
{
if (msg->type() == Message::ThreadMoveMessage) {
if (isRunning()) {
unregisterTimer();
invokeMethod(&Timer::registerTimer,
ConnectionTypeQueued);
}
}
Object::message(msg);
}
} /* namespace libcamera */
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