[libcamera-devel] [RFC v1 7/7] py: cam.py: Use new events support

[Kieran Bingham]

Quoting Tomi Valkeinen (2022-06-23 15:47:36)
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
> ---
>  src/py/cam/cam.py | 31 +++++++++++++++++++++++++------
>  1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/src/py/cam/cam.py b/src/py/cam/cam.py
> index 733e9ae5..538f0c1d 100755
> --- a/src/py/cam/cam.py
> +++ b/src/py/cam/cam.py
> @@ -243,11 +243,7 @@ class CaptureState:
>      # Called from renderer when there is a libcamera event
>      def event_handler(self):
>          try:
> -            reqs = self.cm.get_ready_requests()
> -
> -            for req in reqs:
> -                ctx = next(ctx for ctx in self.contexts if ctx.idx == req.cookie)
> -                self.__request_handler(ctx, req)
> +            self.cm.dispatch_events()
>  
>              running = any(ctx.reqs_completed < ctx.opt_capture for ctx in self.contexts)
>              return running
> @@ -255,7 +251,9 @@ class CaptureState:
>              traceback.print_exc()
>              return False
>  
> -    def __request_handler(self, ctx, req):
> +    def __request_handler(self, cam, req):
> +        ctx = next(ctx for ctx in self.contexts if ctx.camera == cam)
> +
>          if req.status != libcam.Request.Status.Complete:
>              raise Exception('{}: Request failed: {}'.format(ctx.id, req.status))
>  
> @@ -310,6 +308,9 @@ class CaptureState:
>              ctx.camera.queue_request(req)
>              ctx.reqs_queued += 1
>  
> +    def __disconnect_handler(self, cam):
> +        print('Camera', cam, 'disconnected')
> +
>      def __capture_init(self):
>          for ctx in self.contexts:
>              ctx.acquire()
> @@ -323,6 +324,15 @@ class CaptureState:
>          for ctx in self.contexts:
>              ctx.create_requests()
>  
> +        for ctx in self.contexts:
> +            # These cause circular dependencies:
> +            # The callback in the camera points to CaptureState.
> +            # The CaptureState points to the camera.
> +            # This can be solved by setting the callbacks to None after stopping
> +            # or using lambdas here and weakref.WeakMethod.

I wish I could comment here, but I've got nothing specific or useful :S

> +            ctx.camera.request_completed = self.__request_handler
> +            ctx.camera.disconnected = self.__disconnect_handler
> +
>      def __capture_start(self):
>          for ctx in self.contexts:
>              ctx.start()
> @@ -334,6 +344,10 @@ class CaptureState:
>          for ctx in self.contexts:
>              ctx.stop()
>  
> +        for ctx in self.contexts:
> +            ctx.camera.request_completed = None
> +            ctx.camera.disconnected = None
> +
>          for ctx in self.contexts:
>              ctx.release()
>  
> @@ -402,6 +416,9 @@ def main():
>  
>      cm = libcam.CameraManager.singleton()
>  
> +    cm.camera_added = lambda c: print("Camera added:", c)
> +    cm.camera_removed = lambda c: print("Camera removed:", c)
> +
>      if args.list:
>          do_cmd_list(cm)
>  
> @@ -459,6 +476,8 @@ def main():
>  
>          state.do_cmd_capture()
>  
> +        cm.discard_events()
> +
>      return 0
>  
>  
> -- 
> 2.34.1
>