[libcamera-devel] [RFC PATCH] gstreamer: Drop libcamera_private dependency

[Kieran Bingham]

Quoting Barnabás Pőcze via libcamera-devel (2023-06-26 22:52:18)
> Hi
> 
> 
> 2023. június 26., hétfő 23:17 keltezéssel, Umang Jain via libcamera-devel <libcamera-devel at lists.libcamera.org> írta:
> 
> > Drop libcamera_private dependency entirely as to avoid libcamerasrc
> > getting more dependent on it. In order to achieve that, one of the
> > mutex locks in GstLibcameraSrcState needs to be replaced with GMutex.
> > 

Excellent plan! Indeed - gstilbcamerasrc should definitely only use the
public API.


> > However doing so, this won't let us to use the clang's thread annotation
> > macros in libcamera (which should be fine as libcamerasrc would move
> > out of libcamera repo once matured).

I think that's reasonable in this instance.


> > 
> > Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
> > ---
> >  src/gstreamer/gstlibcamerasrc.cpp | 20 ++++++++------------
> >  src/gstreamer/meson.build         |  2 +-
> >  2 files changed, 9 insertions(+), 13 deletions(-)
> > 
> > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > index 11f15068..fda5610f 100644
> > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > @@ -32,8 +32,6 @@
> >  #include <queue>
> >  #include <vector>
> > 
> > -#include <libcamera/base/mutex.h>
> > -
> >  #include <libcamera/camera.h>
> >  #include <libcamera/camera_manager.h>
> >  #include <libcamera/control_ids.h>
> > @@ -125,11 +123,9 @@ struct GstLibcameraSrcState {
> >        * be held while calling into other graph elements (e.g. when calling
> >        * gst_pad_query()).
> >        */
> > -     Mutex lock_;
> > -     std::queue<std::unique_ptr<RequestWrap>> queuedRequests_
> > -             LIBCAMERA_TSA_GUARDED_BY(lock_);
> > -     std::queue<std::unique_ptr<RequestWrap>> completedRequests_
> > -             LIBCAMERA_TSA_GUARDED_BY(lock_);
> > +     GMutex lock_;
> > [...]
> 
> Shouldn't this be initialized? i.e. `g_mutex_init()`?

Looking at https://docs.gtk.org/glib/method.Mutex.init.html
it will also need a g_mutex_clear();

But with those:

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> 
> 
> Regards,
> Barnabás Pőcze