[libcamera-devel] [PATCH v4 3/6] libcamera: camera: Add acquire() and release()
Kieran Bingham
kieran.bingham at ideasonboard.com
Tue Jan 29 10:51:54 CET 2019
Hi Niklas, (/Laurent,)
On 29/01/2019 02:00, Niklas Söderlund wrote:
> From: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>
> Exclusive access must be obtained before performing operations that
> change the device state. Define an internal flag to track ownership and
> provide a means of protecting functions that change device
> configuration.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
With capitalisation comments considered,
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
> include/libcamera/camera.h | 5 +++++
> src/libcamera/camera.cpp | 39 +++++++++++++++++++++++++++++++++++++-
> 2 files changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> index a2ded62de94814c4..7e358f8c0aa093cf 100644
> --- a/include/libcamera/camera.h
> +++ b/include/libcamera/camera.h
> @@ -29,6 +29,9 @@ public:
>
> Signal<Camera *> disconnected;
>
> + int acquire();
> + void release();
> +
> private:
> Camera(PipelineHandler *pipe, const std::string &name);
> ~Camera();
> @@ -38,6 +41,8 @@ private:
>
> std::shared_ptr<PipelineHandler> pipe_;
> std::string name_;
> +
> + bool acquired_;
> };
>
> } /* namespace libcamera */
> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> index 9cec289282e4797b..500976b237bcbd2d 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -102,12 +102,14 @@ const std::string &Camera::name() const
> */
>
> Camera::Camera(PipelineHandler *pipe, const std::string &name)
> - : pipe_(pipe->shared_from_this()), name_(name)
> + : pipe_(pipe->shared_from_this()), name_(name), acquired_(false)
> {
> }
>
> Camera::~Camera()
> {
> + if (acquired_)
> + LOG(Camera, Error) << "Removing camera while still in use";
> }
>
> /**
> @@ -127,4 +129,39 @@ void Camera::disconnect()
> disconnected.emit(this);
> }
>
> +/**
> + * \brief Acquire the camera device for exclusive access
Back on my Doxygen Capitalisation Front....
I think we should be capitalising any use of a class name so that
Doxygen links the types and makes it clear that we are referencing an
object of that type.
> + *
> + * After opening the device with open(), exclusive access must be obtained
> + * before performing operations that change the device state. This function is
> + * not blocking, if the device has already been acquired (by the same or another
> + * process) the -EBUSY error code is returned.
> + *
> + * Once exclusive access isn't needed anymore, the device should be released
> + * with a call to the release() function.
> + *
> + * \todo Implement exclusive access across processes.
> + *
> + * \return 0 on success or a negative error code on error.
> + */
> +int Camera::acquire()
> +{
> + if (acquired_)
> + return -EBUSY;
> +
> + acquired_ = true;
> + return 0;
> +}
> +
> +/**
> + * \brief Release exclusive access to the camera device
s/camera/Camera/
> + *
> + * Releasing the camera device allows other users to acquire exclusive access
s/camera/Camera/
> + * with the acquire() function.
> + */
> +void Camera::release()
> +{
> + acquired_ = false;
> +}
> +
> } /* namespace libcamera */
>
--
Regards
--
Kieran
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