[libcamera-devel] [PATCH v2 06/19] py: Add CameraManager.read_event()
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Fri May 27 13:04:38 CEST 2022
Hi Tomi,
On Fri, May 27, 2022 at 09:00:44AM +0300, Tomi Valkeinen wrote:
> On 26/05/2022 18:27, Laurent Pinchart wrote:
> > On Tue, May 24, 2022 at 02:45:57PM +0300, Tomi Valkeinen wrote:
> >> Add CameraManager.read_event() so that the user does not need to call
> >> os.read().
> >>
> >> We use eventfd, and we must always read 8 bytes. Hiding that inside
> >> read_event() makes sense.
> >>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
> >> ---
> >> src/py/cam/cam.py | 3 +--
> >> src/py/libcamera/py_main.cpp | 8 ++++++++
> >> test/py/unittests.py | 3 +--
> >> 3 files changed, 10 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/src/py/cam/cam.py b/src/py/cam/cam.py
> >> index e2bc78da..66df18bf 100755
> >> --- a/src/py/cam/cam.py
> >> +++ b/src/py/cam/cam.py
> >> @@ -9,7 +9,6 @@
> >> import argparse
> >> import binascii
> >> import libcamera as libcam
> >> -import os
> >> import sys
> >> import traceback
> >>
> >> @@ -294,7 +293,7 @@ def event_handler(state):
> >> cm = state['cm']
> >> contexts = state['contexts']
> >>
> >> - os.read(cm.efd, 8)
> >> + cm.read_event()
> >>
> >> reqs = cm.get_ready_requests()
> >
> > Would it make sense to read the event within get_ready_requests() ?
>
> I thought about these two functions, but this seemed the safest to me.
> If get_ready_requests() would do read_event(), then you could not call
> get_ready_requests() unless you knew there is an event waiting, or it
> would block. Or we could make the fd non-blocking, but I think that's
> usually the choice of the user, not the library.
Hmmm... I have a feeling we can do better, but I don't know what yet :-)
It doesn't have to be done now.
--
Regards,
Laurent Pinchart
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