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

[Jacopo Mondi]

Hi Laurent

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' ?

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
>
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel at lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel
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