[libcamera-devel,RFC,17/17] Documentation: guides: pipeline-handler: Migrate to Camera::Private
diff mbox series

Message ID 20210723040036.32346-18-laurent.pinchart@ideasonboard.com
State Superseded
Headers show
Series
  • libcamera: Replace CameraData with Camera::Private
Related show

Commit Message

Laurent Pinchart July 23, 2021, 4 a.m. UTC
Update the pipeline handler guide following the migration from the
CameraData class to the Camera::Private class.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 Documentation/guides/pipeline-handler.rst | 67 ++++++++++++-----------
 1 file changed, 34 insertions(+), 33 deletions(-)

Comments

Niklas Söderlund July 24, 2021, 7:35 a.m. UTC | #1
Hi Laurent,

Thanks for your work.

On 2021-07-23 07:00:36 +0300, Laurent Pinchart wrote:
> Update the pipeline handler guide following the migration from the
> CameraData class to the Camera::Private class.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

> ---
>  Documentation/guides/pipeline-handler.rst | 67 ++++++++++++-----------
>  1 file changed, 34 insertions(+), 33 deletions(-)
> 
> diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
> index 152776935a33..7e9ff824dd50 100644
> --- a/Documentation/guides/pipeline-handler.rst
> +++ b/Documentation/guides/pipeline-handler.rst
> @@ -106,7 +106,7 @@ functionalities descibed above. Below is a brief overview of each of those:
>     Abstracts camera sensor handling by hiding the details of the V4L2 subdevice
>     kernel API and caching sensor information.
>  
> --  `CameraData <http://libcamera.org/api-html/classlibcamera_1_1CameraData.html>`_:
> +-  `Camera::Private <http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html>`_:
>     Represents device-specific data a pipeline handler associates to each Camera
>     instance.
>  
> @@ -416,26 +416,26 @@ receivers port output.
>  The Pipeline Handler is responsible for defining the set of Streams associated
>  with the Camera.
>  
> -Each Camera has instance-specific data represented using the `CameraData`_
> +Each Camera has instance-specific data represented using the `Camera::Private`_
>  class, which can be extended for the specific needs of the pipeline handler.
>  
> -.. _CameraData: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html
> +.. _Camera::Private: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html
>  
>  
> -To support the Camera we will later register, we need to create a CameraData
> +To support the Camera we will later register, we need to create a Camera::Private
>  class that we can implement for our specific Pipeline Handler.
>  
> -Define a new ``VividCameraData()`` class derived from ``CameraData`` by adding
> -the following code before the PipelineHandlerVivid class definition where it
> -will be used:
> +Define a new ``VividCameraPrivate()`` class derived from ``Camera::Private`` by
> +adding the following code before the PipelineHandlerVivid class definition where
> +it will be used:
>  
>  .. code-block:: cpp
>  
> -   class VividCameraData : public CameraData
> +   class VividCameraData : public Camera::Private
>     {
>     public:
>            VividCameraData(PipelineHandler *pipe, MediaDevice *media)
> -                : CameraData(pipe), media_(media), video_(nullptr)
> +                : Camera::Private(pipe), media_(media), video_(nullptr)
>            {
>            }
>  
> @@ -457,17 +457,17 @@ single stream, represented by the ``VividCameraData`` class members. More
>  complex pipeline handlers might register cameras composed of several video
>  devices and sub-devices, or multiple streams per camera that represent the
>  several components of the image capture pipeline. You should represent all these
> -components in the ``CameraData`` derived class when developing a custom
> +components in the ``Camera::Private`` derived class when developing a custom
>  PipelineHandler.
>  
>  In our example VividCameraData we implement an ``init()`` function to prepare
> -the object from our PipelineHandler, however the CameraData class does not
> +the object from our PipelineHandler, however the Camera::Private class does not
>  specify the interface for initialisation and PipelineHandlers can manage this
> -based on their own needs. Derived CameraData classes are used only by their
> +based on their own needs. Derived Camera::Private classes are used only by their
>  respective pipeline handlers.
>  
> -The CameraData class stores the context required for each camera instance and
> -is usually responsible for opening all Devices used in the capture pipeline.
> +The Camera::Private class stores the context required for each camera instance
> +and is usually responsible for opening all Devices used in the capture pipeline.
>  
>  We can now implement the ``init`` method for our example Pipeline Handler to
>  create a new V4L2 video device from the media entity, which we can specify using
> @@ -488,11 +488,11 @@ capture device named 'vivid-000-vid-cap' by the device.
>            return 0;
>     }
>  
> -The CameraData should be created and initialised before we move on to register a
> -new Camera device so we need to construct and initialise our
> +The VividCameraData should be created and initialised before we move on to
> +register a new Camera device so we need to construct and initialise our
>  VividCameraData after we have identified our device within
>  PipelineHandlerVivid::match(). The VividCameraData is wrapped by a
> -std::unique_ptr to help manage the lifetime of our CameraData instance.
> +std::unique_ptr to help manage the lifetime of the instance.
>  
>  If the camera data initialization fails, return ``false`` to indicate the
>  failure to the ``match()`` method and prevent retrying of the pipeline handler.
> @@ -508,9 +508,9 @@ failure to the ``match()`` method and prevent retrying of the pipeline handler.
>  Once the camera data has been initialized, the Camera device instances and the
>  associated streams have to be registered. Create a set of streams for the
>  camera, which for this device is only one. You create a camera using the static
> -`Camera::create`_ method, passing the pipeline handler, the id of the camera,
> -and the streams available. Then register the camera and its data with the
> -pipeline handler and camera manager using `registerCamera`_.
> +`Camera::create`_ method, passing the Camera::Private instance, the id of the
> +camera, and the streams available. Then register the camera with the pipeline
> +handler and camera manager using `registerCamera`_.
>  
>  Finally with a successful construction, we return 'true' indicating that the
>  PipelineHandler successfully matched and constructed a device.
> @@ -548,23 +548,24 @@ Our match function should now look like the following:
>  
>     	/* Create and register the camera. */
>     	std::set<Stream *> streams{ &data->stream_ };
> -   	std::shared_ptr<Camera> camera = Camera::create(this, data->video_->deviceName(), streams);
> -   	registerCamera(std::move(camera), std::move(data));
> +        const std::string &id = data->video_->deviceName();
> +   	std::shared_ptr<Camera> camera = Camera::create(data.release(), id, streams);
> +   	registerCamera(std::move(camera));
>  
>     	return true;
>     }
>  
> -We will need to use our custom CameraData class frequently throughout the
> +We will need to use our custom VividCameraData class frequently throughout the
>  pipeline handler, so we add a private convenience helper to our Pipeline handler
> -to obtain and cast the custom CameraData instance from a Camera instance.
> +to obtain and cast the custom VividCameraData instance from a Camera::Private
> +instance.
>  
>  .. code-block:: cpp
>  
>     private:
> -       VividCameraData *cameraData(const Camera *camera)
> +       VividCameraData *cameraData(Camera *camera)
>         {
> -               return static_cast<VividCameraData *>(
> -                        PipelineHandler::cameraData(camera));
> +               return static_cast<VividCameraData *>(camera->_d());
>         }
>  
>  At this point, you need to add the following new includes to provide the Camera
> @@ -594,12 +595,12 @@ are defined by src/libcamera/`properties_ids.yaml`_.
>  
>  Pipeline handlers can optionally register the list of controls an application
>  can set as well as a list of immutable camera properties. Being both
> -Camera-specific values, they are represented in the ``CameraData`` base class,
> -which provides two members for this purpose: the `CameraData::controlInfo_`_ and
> -the `CameraData::properties_`_ fields.
> +Camera-specific values, they are represented in the ``Camera::Private`` base
> +class, which provides two members for this purpose: the
> +`Camera::Private::controlInfo_`_ and the `Camera::Private::properties_`_ fields.
>  
> -.. _CameraData::controlInfo_: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html#ab9fecd05c655df6084a2233872144a52
> -.. _CameraData::properties_: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html#a84002c29f45bd35566c172bb65e7ec0b
> +.. _Camera::Private::controlInfo_: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html#ab4e183eb4dabe929d1b2bbbb519b969f
> +.. _Camera::Private::properties_: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html#ad31f12f5ed9c1fbe25750902f4791064
>  
>  The ``controlInfo_`` field represents a map of ``ControlId`` instances
>  associated with the limits of valid values supported for the control. More
> @@ -617,7 +618,7 @@ Complete the initialization of the ``VividCameraData`` class by adding the
>  following code to the ``VividCameraData::init()`` method to initialise the
>  controls. For more complex control configurations, this could of course be
>  broken out to a separate function, but for now we just initialise the small set
> -inline in our CameraData init:
> +inline in our VividCameraData init:
>  
>  .. code-block:: cpp
>  
> -- 
> Regards,
> 
> Laurent Pinchart
>

Patch
diff mbox series

diff --git a/Documentation/guides/pipeline-handler.rst b/Documentation/guides/pipeline-handler.rst
index 152776935a33..7e9ff824dd50 100644
--- a/Documentation/guides/pipeline-handler.rst
+++ b/Documentation/guides/pipeline-handler.rst
@@ -106,7 +106,7 @@  functionalities descibed above. Below is a brief overview of each of those:
    Abstracts camera sensor handling by hiding the details of the V4L2 subdevice
    kernel API and caching sensor information.
 
--  `CameraData <http://libcamera.org/api-html/classlibcamera_1_1CameraData.html>`_:
+-  `Camera::Private <http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html>`_:
    Represents device-specific data a pipeline handler associates to each Camera
    instance.
 
@@ -416,26 +416,26 @@  receivers port output.
 The Pipeline Handler is responsible for defining the set of Streams associated
 with the Camera.
 
-Each Camera has instance-specific data represented using the `CameraData`_
+Each Camera has instance-specific data represented using the `Camera::Private`_
 class, which can be extended for the specific needs of the pipeline handler.
 
-.. _CameraData: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html
+.. _Camera::Private: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html
 
 
-To support the Camera we will later register, we need to create a CameraData
+To support the Camera we will later register, we need to create a Camera::Private
 class that we can implement for our specific Pipeline Handler.
 
-Define a new ``VividCameraData()`` class derived from ``CameraData`` by adding
-the following code before the PipelineHandlerVivid class definition where it
-will be used:
+Define a new ``VividCameraPrivate()`` class derived from ``Camera::Private`` by
+adding the following code before the PipelineHandlerVivid class definition where
+it will be used:
 
 .. code-block:: cpp
 
-   class VividCameraData : public CameraData
+   class VividCameraData : public Camera::Private
    {
    public:
           VividCameraData(PipelineHandler *pipe, MediaDevice *media)
-                : CameraData(pipe), media_(media), video_(nullptr)
+                : Camera::Private(pipe), media_(media), video_(nullptr)
           {
           }
 
@@ -457,17 +457,17 @@  single stream, represented by the ``VividCameraData`` class members. More
 complex pipeline handlers might register cameras composed of several video
 devices and sub-devices, or multiple streams per camera that represent the
 several components of the image capture pipeline. You should represent all these
-components in the ``CameraData`` derived class when developing a custom
+components in the ``Camera::Private`` derived class when developing a custom
 PipelineHandler.
 
 In our example VividCameraData we implement an ``init()`` function to prepare
-the object from our PipelineHandler, however the CameraData class does not
+the object from our PipelineHandler, however the Camera::Private class does not
 specify the interface for initialisation and PipelineHandlers can manage this
-based on their own needs. Derived CameraData classes are used only by their
+based on their own needs. Derived Camera::Private classes are used only by their
 respective pipeline handlers.
 
-The CameraData class stores the context required for each camera instance and
-is usually responsible for opening all Devices used in the capture pipeline.
+The Camera::Private class stores the context required for each camera instance
+and is usually responsible for opening all Devices used in the capture pipeline.
 
 We can now implement the ``init`` method for our example Pipeline Handler to
 create a new V4L2 video device from the media entity, which we can specify using
@@ -488,11 +488,11 @@  capture device named 'vivid-000-vid-cap' by the device.
           return 0;
    }
 
-The CameraData should be created and initialised before we move on to register a
-new Camera device so we need to construct and initialise our
+The VividCameraData should be created and initialised before we move on to
+register a new Camera device so we need to construct and initialise our
 VividCameraData after we have identified our device within
 PipelineHandlerVivid::match(). The VividCameraData is wrapped by a
-std::unique_ptr to help manage the lifetime of our CameraData instance.
+std::unique_ptr to help manage the lifetime of the instance.
 
 If the camera data initialization fails, return ``false`` to indicate the
 failure to the ``match()`` method and prevent retrying of the pipeline handler.
@@ -508,9 +508,9 @@  failure to the ``match()`` method and prevent retrying of the pipeline handler.
 Once the camera data has been initialized, the Camera device instances and the
 associated streams have to be registered. Create a set of streams for the
 camera, which for this device is only one. You create a camera using the static
-`Camera::create`_ method, passing the pipeline handler, the id of the camera,
-and the streams available. Then register the camera and its data with the
-pipeline handler and camera manager using `registerCamera`_.
+`Camera::create`_ method, passing the Camera::Private instance, the id of the
+camera, and the streams available. Then register the camera with the pipeline
+handler and camera manager using `registerCamera`_.
 
 Finally with a successful construction, we return 'true' indicating that the
 PipelineHandler successfully matched and constructed a device.
@@ -548,23 +548,24 @@  Our match function should now look like the following:
 
    	/* Create and register the camera. */
    	std::set<Stream *> streams{ &data->stream_ };
-   	std::shared_ptr<Camera> camera = Camera::create(this, data->video_->deviceName(), streams);
-   	registerCamera(std::move(camera), std::move(data));
+        const std::string &id = data->video_->deviceName();
+   	std::shared_ptr<Camera> camera = Camera::create(data.release(), id, streams);
+   	registerCamera(std::move(camera));
 
    	return true;
    }
 
-We will need to use our custom CameraData class frequently throughout the
+We will need to use our custom VividCameraData class frequently throughout the
 pipeline handler, so we add a private convenience helper to our Pipeline handler
-to obtain and cast the custom CameraData instance from a Camera instance.
+to obtain and cast the custom VividCameraData instance from a Camera::Private
+instance.
 
 .. code-block:: cpp
 
    private:
-       VividCameraData *cameraData(const Camera *camera)
+       VividCameraData *cameraData(Camera *camera)
        {
-               return static_cast<VividCameraData *>(
-                        PipelineHandler::cameraData(camera));
+               return static_cast<VividCameraData *>(camera->_d());
        }
 
 At this point, you need to add the following new includes to provide the Camera
@@ -594,12 +595,12 @@  are defined by src/libcamera/`properties_ids.yaml`_.
 
 Pipeline handlers can optionally register the list of controls an application
 can set as well as a list of immutable camera properties. Being both
-Camera-specific values, they are represented in the ``CameraData`` base class,
-which provides two members for this purpose: the `CameraData::controlInfo_`_ and
-the `CameraData::properties_`_ fields.
+Camera-specific values, they are represented in the ``Camera::Private`` base
+class, which provides two members for this purpose: the
+`Camera::Private::controlInfo_`_ and the `Camera::Private::properties_`_ fields.
 
-.. _CameraData::controlInfo_: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html#ab9fecd05c655df6084a2233872144a52
-.. _CameraData::properties_: http://libcamera.org/api-html/classlibcamera_1_1CameraData.html#a84002c29f45bd35566c172bb65e7ec0b
+.. _Camera::Private::controlInfo_: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html#ab4e183eb4dabe929d1b2bbbb519b969f
+.. _Camera::Private::properties_: http://libcamera.org/api-html/classlibcamera_1_1Camera_1_1Private.html#ad31f12f5ed9c1fbe25750902f4791064
 
 The ``controlInfo_`` field represents a map of ``ControlId`` instances
 associated with the limits of valid values supported for the control. More
@@ -617,7 +618,7 @@  Complete the initialization of the ``VividCameraData`` class by adding the
 following code to the ``VividCameraData::init()`` method to initialise the
 controls. For more complex control configurations, this could of course be
 broken out to a separate function, but for now we just initialise the small set
-inline in our CameraData init:
+inline in our VividCameraData init:
 
 .. code-block:: cpp