[libcamera-devel] [PATCH 01/13] gstreamer: Use gst_task_resume() when available

[Laurent Pinchart]

Hi Vedant,

On Mon, Jun 27, 2022 at 08:10:04PM +0200, Vedant Paranjape wrote:
> Hello Laurent,
> 
> I am not sure if I am well versed enough in gstreaner to review this,
> but here are few of my comments, pardon me if they are wrong ;)

Reviews are always appreciated :-)

> On Fri, Jun 24, 2022 at 1:22 AM Laurent Pinchart wrote:
> >
> > The gst_libcamera_resume_task() helper is an implementation of the
> > gst_task_resume() function that predates its addition to GStreamer. Use
> > gst_task_resume() when available, and rename gst_libcamera_resume_task()
> > to gst_task_resume() to support older GStreamer versions.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/gstreamer/gstlibcamera-utils.cpp | 16 ++++++++++------
> >  src/gstreamer/gstlibcamera-utils.h   |  4 +++-
> >  src/gstreamer/gstlibcamerasrc.cpp    |  4 ++--
> >  3 files changed, 15 insertions(+), 9 deletions(-)
> >
> > diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp
> > index 3f2422863c03..c97c0d438de2 100644
> > --- a/src/gstreamer/gstlibcamera-utils.cpp
> > +++ b/src/gstreamer/gstlibcamera-utils.cpp
> > @@ -224,16 +224,20 @@ gst_libcamera_configure_stream_from_caps(StreamConfiguration &stream_cfg,
> >         stream_cfg.size.height = height;
> >  }
> >
> > -void
> > -gst_libcamera_resume_task(GstTask *task)
> > +#if !GST_CHECK_VERSION(1, 17, 1)
> > +gboolean
> > +gst_task_resume(GstTask *task)
> >  {
> >         /* We only want to resume the task if it's paused. */
> >         GLibLocker lock(GST_OBJECT(task));
> > -       if (GST_TASK_STATE(task) == GST_TASK_PAUSED) {
> > -               GST_TASK_STATE(task) = GST_TASK_STARTED;
> > -               GST_TASK_SIGNAL(task);
> > -       }
> > +       if (GST_TASK_STATE(task) != GST_TASK_PAUSED)
> > +               return FALSE;
> > +
> > +       GST_TASK_STATE(task) = GST_TASK_STARTED;
> > +       GST_TASK_SIGNAL(task);
> > +       return TRUE;
> >  }
> > +#endif
> 
> I had a small doubt, shouldn't this replicate the function defined
> here ? https://gitlab.freedesktop.org/gstreamer/gstreamer/blob/1.18.4/gst/gsttask.c#L865

Ideally, yes, but that calls gst_task_set_state_unlocked(), which is an
internal static function. I could copy its code here too, but as far as
I understand, the above implementation should be functionally equivalent
for our use cases (I think that was Nicolas' intent at least).

> >  G_LOCK_DEFINE_STATIC(cm_singleton_lock);
> >  static std::weak_ptr<CameraManager> cm_singleton_ptr;
> > diff --git a/src/gstreamer/gstlibcamera-utils.h b/src/gstreamer/gstlibcamera-utils.h
> > index d54f15885d0c..164189a28965 100644
> > --- a/src/gstreamer/gstlibcamera-utils.h
> > +++ b/src/gstreamer/gstlibcamera-utils.h
> > @@ -18,7 +18,9 @@ GstCaps *gst_libcamera_stream_formats_to_caps(const libcamera::StreamFormats &fo
> >  GstCaps *gst_libcamera_stream_configuration_to_caps(const libcamera::StreamConfiguration &stream_cfg);
> >  void gst_libcamera_configure_stream_from_caps(libcamera::StreamConfiguration &stream_cfg,
> >                                               GstCaps *caps);
> > -void gst_libcamera_resume_task(GstTask *task);
> > +#if !GST_CHECK_VERSION(1, 17, 1)
> > +gboolean gst_task_resume(GstTask *task);
> > +#endif
> >  std::shared_ptr<libcamera::CameraManager> gst_libcamera_get_camera_manager(int &ret);
> >
> >  /**
> > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > index 46fd02d207be..9d6be075a474 100644
> > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > @@ -192,7 +192,7 @@ GstLibcameraSrcState::requestCompleted(Request *request)
> >                 gst_libcamera_pad_queue_buffer(srcpad, buffer);
> >         }
> >
> > -       gst_libcamera_resume_task(this->src_->task);
> > +       gst_task_resume(src_->task);
> >  }
> >
> >  static bool
> > @@ -453,7 +453,7 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
> >                 GstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator,
> >                                                                 stream_cfg.stream());
> >                 g_signal_connect_swapped(pool, "buffer-notify",
> > -                                        G_CALLBACK(gst_libcamera_resume_task), task);
> > +                                        G_CALLBACK(gst_task_resume), task);
> >
> >                 gst_libcamera_pad_set_pool(srcpad, pool);
> >                 gst_flow_combiner_add_pad(self->flow_combiner, srcpad);

-- 
Regards,

Laurent Pinchart