libcamera: pipeline_handler: Move CameraData members to Camera::Private

With pipeline handlers now being able to subclass Camera::Private, start
the migration from CameraData to Camera::Private by moving the members
of the base CameraData class. The controlInfo_, properties_ and pipe_
members are duplicated for now, to allow migrating pipeline handlers one
by one.

The Camera::Private class is now properly documented, don't exclude it
from documentation generation.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/camera.cpp

@@ -332,13 +332,25 @@ std::size_t CameraConfiguration::size() const
  * \brief The vector of stream configurations
  */
 
+/**
+ * \class Camera::Private
+ * \brief Base class for camera private data
+ *
+ * The Camera::Private class stores all private data associated with a camera.
+ * In addition to hiding core Camera data from the public API, it is expected to
+ * be subclassed by pipeline handlers to store pipeline-specific data.
+ *
+ * Pipeline handlers can obtain the Camera::Private instance associated with a
+ * camera by calling Camera::_d().
+ */
+
 /**
  * \brief Construct a Camera::Private instance
  * \param[in] pipe The pipeline handler responsible for the camera device
  */
 Camera::Private::Private(PipelineHandler *pipe)
-	: pipe_(pipe->shared_from_this()), disconnected_(false),
-	  state_(CameraAvailable)
+	: requestSequence_(0), pipe_(pipe->shared_from_this()),
+	  disconnected_(false), state_(CameraAvailable)
 {
 }
 
@@ -348,6 +360,55 @@ Camera::Private::~Private()
 		LOG(Camera, Error) << "Removing camera while still in use";
 }
 
+/**
+ * \fn Camera::Private::pipe()
+ * \brief Retrieve the pipeline handler related to this camera
+ * \return The pipeline handler that created this camera
+ */
+
+/**
+ * \var Camera::Private::queuedRequests_
+ * \brief The list of queued and not yet completed request
+ *
+ * The list of queued request is used to track requests queued in order to
+ * ensure completion of all requests when the pipeline handler is stopped.
+ *
+ * \sa PipelineHandler::queueRequest(), PipelineHandler::stop(),
+ * PipelineHandler::completeRequest()
+ */
+
+/**
+ * \var Camera::Private::controlInfo_
+ * \brief The set of controls supported by the camera
+ *
+ * The control information shall be initialised by the pipeline handler when
+ * creating the camera.
+ *
+ * \todo This member was initially meant to stay constant after the camera is
+ * created. Several pipeline handlers are already updating it when the camera
+ * is configured. Update the documentation accordingly, and possibly the API as
+ * well, when implementing official support for control info updates.
+ */
+
+/**
+ * \var Camera::Private::properties_
+ * \brief The list of properties supported by the camera
+ *
+ * The list of camera properties shall be initialised by the pipeline handler
+ * when creating the camera, and shall not be modified afterwards.
+ */
+
+/**
+ * \var Camera::Private::requestSequence_
+ * \brief The queuing sequence of the request
+ *
+ * When requests are queued, they are given a per-camera sequence number to
+ * facilitate debugging of internal request usage.
+ *
+ * The requestSequence_ tracks the number of requests queued to a camera
+ * over its lifetime.
+ */
+
 static const char *const camera_state_names[] = {
 	"Available",
 	"Acquired",