[libcamera-devel] [PATCH v8 1/4] cam: event_loop: Add timer events to event loop
Eric Curtin
ecurtin at redhat.com
Wed May 11 13:33:00 CEST 2022
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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