[PATCH 4/4] libcamera: Make Camera::Private::isAcquired() protected

[Cheng-Hao Yang]

Hi Kieran,

On Sun, Oct 20, 2024 at 6:47 AM Kieran Bingham
<kieran.bingham at ideasonboard.com> wrote:
>
> Quoting Harvey Yang (2024-10-18 08:57:37)
> > As some pipeline handlers need to know if a CameraData is currently
> > acquired, this patch makes the function protected, instead of private.
> >
> > For example, the upcoming mtkisp7 needs the information to determine if
> > it should send camera disconnect signal.
>
> Why? If a camera is disconnected - it should always send a disconnect
> signal to any listener.
>
> It means the application must no longer even remember the camera
> existed!

This is particularly needed for IPA disconnection:
Pipeline handler holds the IPA proxy, so it needs to decide if calling
a camera's
disconnected signal is proper.

If you think that IPA proxy disconnection is another thing, apart from
a camera's
disconnection, we can also consider adding another signal.

BR,
Harvey

>
> --
> Kieran
>
>
> >
> > Signed-off-by: Harvey Yang <chenghaoyang at chromium.org>
> > Co-developed-by: Yudhistira Erlandinata <yerlandinata at chromium.org>
> > Signed-off-by: Yudhistira Erlandinata <yerlandinata at chromium.org>
> > ---
> >  include/libcamera/internal/camera.h | 4 +++-
> >  src/libcamera/camera.cpp            | 3 +++
> >  2 files changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/libcamera/internal/camera.h b/include/libcamera/internal/camera.h
> > index 0bef0980e..fe47a49b7 100644
> > --- a/include/libcamera/internal/camera.h
> > +++ b/include/libcamera/internal/camera.h
> > @@ -43,6 +43,9 @@ public:
> >
> >         const CameraControlValidator *validator() const { return validator_.get(); }
> >
> > +protected:
> > +       bool isAcquired() const;
> > +
> >  private:
> >         enum State {
> >                 CameraAvailable,
> > @@ -52,7 +55,6 @@ private:
> >                 CameraRunning,
> >         };
> >
> > -       bool isAcquired() const;
> >         bool isRunning() const;
> >         int isAccessAllowed(State state, bool allowDisconnected = false,
> >                             const char *from = __builtin_FUNCTION()) const;
> > diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> > index ef5a6725f..38aa4ad22 100644
> > --- a/src/libcamera/camera.cpp
> > +++ b/src/libcamera/camera.cpp
> > @@ -670,6 +670,9 @@ static const char *const camera_state_names[] = {
> >         "Running",
> >  };
> >
> > +/**
> > + * \return True if the camera is acquired, false otherwise
> > + */
> >  bool Camera::Private::isAcquired() const
> >  {
> >         return state_.load(std::memory_order_acquire) != CameraAvailable;
> > --
> > 2.47.0.rc1.288.g06298d1525-goog
> >