[libcamera-devel] [PATCH 8/9] libcamera: timer: Add start() method with absolute deadline

[Laurent Pinchart]

Hi Jacopo,

On Sun, Oct 06, 2019 at 09:34:38PM +0200, Jacopo Mondi wrote:
> On Sun, Oct 06, 2019 at 08:32:25AM +0300, Laurent Pinchart wrote:
> > The Timer class is started using a timer duration. To help callers that
> > require waiting for an absolute deadline, add a start() overload that
> > takes a std::chrono::steady_clock::time_point value. This will be used
> > by IPAs.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  include/libcamera/timer.h |  1 +
> >  src/libcamera/timer.cpp   | 22 +++++++++++++++++++---
> >  2 files changed, 20 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/libcamera/timer.h b/include/libcamera/timer.h
> > index 3540efb41b6f..34e7b8ac8e87 100644
> > --- a/include/libcamera/timer.h
> > +++ b/include/libcamera/timer.h
> > @@ -25,6 +25,7 @@ public:
> >
> >  	void start(unsigned int msec) { start(std::chrono::milliseconds(msec)); }
> >  	void start(std::chrono::milliseconds duration);
> > +	void start(std::chrono::steady_clock::time_point deadline);
> >  	void stop();
> >  	bool isRunning() const;
> >
> > diff --git a/src/libcamera/timer.cpp b/src/libcamera/timer.cpp
> > index 8749d66c8662..705ce60b8fbd 100644
> > --- a/src/libcamera/timer.cpp
> > +++ b/src/libcamera/timer.cpp
> > @@ -37,6 +37,11 @@ LOG_DEFINE_CATEGORY(Timer)
> >   * 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 past or the current time,
> 
> 'to the past of the current time' or
> 'to the past or to the current time' ?

The second option. I'll change that.

> otherwise
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> 
> > + * 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
> > @@ -74,17 +79,28 @@ Timer::~Timer()
> >   * the timer is already running it will be stopped and restarted.
> >   */
> >  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
> > + *
> > + * This method shall be called from the thread the timer is associated with. If
> > + * the timer is already running it will be stopped and restarted.
> > + */
> > +void Timer::start(std::chrono::steady_clock::time_point deadline)
> >  {
> >  	if (Thread::current() != thread()) {
> >  		LOG(Timer, Error) << "Timer can't be started from another thread";
> >  		return;
> >  	}
> >
> > -	deadline_ = utils::clock::now() + duration;
> > +	deadline_ = deadline;
> >
> >  	LOG(Timer, Debug)
> > -		<< "Starting timer " << this << " with duration "
> > -		<< duration.count() << ": deadline "
> > +		<< "Starting timer " << this << ": deadline "
> >  		<< utils::time_point_to_string(deadline_);
> >
> >  	if (isRunning())

-- 
Regards,

Laurent Pinchart