[libcamera-devel] [PATCH v8 1/4] cam: event_loop: Add timer events to event loop

[Eric Curtin]

Another friendly reminder. In case you guys get the opportunity.

On Wed 11 May 2022, 12:33 Eric Curtin, <ecurtin at redhat.com> wrote:

> On Thu, 5 May 2022 at 16:19, Eric Curtin <ecurtin at redhat.com> wrote:
> >
> > Extend the EventLoop class to support periodic timer events. This can be
> > used to run tasks periodically, such as handling the event loop of SDL.
> >
> > Also delete all events in the list, before we event_base_loopbreak.
> >
> > Signed-off-by: Eric Curtin <ecurtin at redhat.com>
> > ---
> >  src/cam/event_loop.cpp | 33 +++++++++++++++++++++++++++++++++
> >  src/cam/event_loop.h   |  6 ++++++
> >  2 files changed, 39 insertions(+)
> >
> > diff --git a/src/cam/event_loop.cpp b/src/cam/event_loop.cpp
> > index e25784c0..181c971c 100644
> > --- a/src/cam/event_loop.cpp
> > +++ b/src/cam/event_loop.cpp
> > @@ -47,6 +47,10 @@ int EventLoop::exec()
> >  void EventLoop::exit(int code)
> >  {
> >         exitCode_ = code;
> > +       for (auto const &e : events_) {
> > +               event_del(e->event_);
> > +       }
> > +
> >         event_base_loopbreak(base_);
> >  }
> >
> > @@ -84,6 +88,35 @@ void EventLoop::addEvent(int fd, EventType type,
> >         events_.push_back(std::move(event));
> >  }
> >
> > +void EventLoop::toTimeval(const std::chrono::milliseconds d, struct
> timeval &tv)
> > +{
> > +       tv.tv_sec =
> std::chrono::duration_cast<std::chrono::seconds>(d).count();
> > +       tv.tv_usec =
> std::chrono::duration_cast<std::chrono::microseconds>(d).count();
> > +}
> > +
> > +void EventLoop::addTimerEvent(const std::chrono::milliseconds d,
> > +                             const std::function<void()> &callback)
> > +{
> > +       std::unique_ptr<Event> event = std::make_unique<Event>(callback);
> > +       event->event_ = event_new(base_, -1, EV_PERSIST,
> &EventLoop::Event::dispatch,
> > +                                 event.get());
> > +       if (!event->event_) {
> > +               std::cerr << "Failed to create timer event" << std::endl;
> > +               return;
> > +       }
> > +
> > +       struct timeval tv;
> > +       toTimeval(d, tv);
> > +
> > +       int ret = event_add(event->event_, &tv);
> > +       if (ret < 0) {
> > +               std::cerr << "Failed to add timer event" << std::endl;
> > +               return;
> > +       }
> > +
> > +       events_.push_back(std::move(event));
> > +}
> > +
> >  void EventLoop::dispatchCallback([[maybe_unused]] evutil_socket_t fd,
> >                                  [[maybe_unused]] short flags, void
> *param)
> >  {
> > diff --git a/src/cam/event_loop.h b/src/cam/event_loop.h
> > index a4613eb2..89215dce 100644
> > --- a/src/cam/event_loop.h
> > +++ b/src/cam/event_loop.h
> > @@ -14,6 +14,8 @@
> >
> >  #include <event2/util.h>
> >
> > +using namespace std::chrono_literals;
> > +
> >  struct event_base;
> >
> >  class EventLoop
> > @@ -37,6 +39,9 @@ public:
> >         void addEvent(int fd, EventType type,
> >                       const std::function<void()> &handler);
> >
> > +       void addTimerEvent(const std::chrono::milliseconds d,
> > +                          const std::function<void()> &handler);
> > +
> >  private:
> >         struct Event {
> >                 Event(const std::function<void()> &callback);
> > @@ -57,6 +62,7 @@ private:
> >         std::list<std::unique_ptr<Event>> events_;
> >         std::mutex lock_;
> >
> > +       void toTimeval(const std::chrono::milliseconds d, struct timeval
> &tv);
> >         static void dispatchCallback(evutil_socket_t fd, short flags,
> >                                      void *param);
> >         void dispatchCall();
> > --
> > 2.35.1
> >
>
> Hi Guys,
>
> Friendly reminder if you could review once you get a spare moment.
>
> Regards,
>
> Eric
>
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