android: camera_buffer: Implement libcamera::Extensible

In order to prepare to support more memory backends, make the
CameraBuffer class implement the PIMPL (pointer-to-implementation)
pattern by inheriting from the libcamera::Extensible class.

Temporary maintain libcamera::MappedBuffer as the CameraBuffer base
class to maintain compatibility of the CameraStream::process() interface
that requires a MappedBuffer * as second argument and will be converted
to use a CameraBuffer in the next patch.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

src/android/camera_buffer.h

@@ -9,13 +9,25 @@
 
 #include <hardware/camera3.h>
 
+#include <libcamera/class.h>
 #include <libcamera/internal/buffer.h>
+#include <libcamera/span.h>
 
-class CameraBuffer : public libcamera::MappedBuffer
+class CameraBuffer final : public libcamera::Extensible,
+			   public libcamera::MappedBuffer
 {
+	LIBCAMERA_DECLARE_PRIVATE(CameraBuffer)
+
 public:
 	CameraBuffer(buffer_handle_t camera3Buffer, int flags);
 	~CameraBuffer();
+
+	bool isValid() const;
+
+	unsigned int numPlanes() const;
+
+	libcamera::Span<const uint8_t> plane(unsigned int plane) const;
+	libcamera::Span<uint8_t> plane(unsigned int plane);
 };
 
 #endif /* __ANDROID_CAMERA_BUFFER_H__ */

src/android/mm/generic_camera_buffer.cpp

@@ -13,7 +13,24 @@ using namespace libcamera;
 
 LOG_DECLARE_CATEGORY(HAL)
 
-CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)
+class CameraBuffer::Private : public Extensible::Private,
+			      public libcamera::MappedBuffer
+{
+	LIBCAMERA_DECLARE_PUBLIC(CameraBuffer)
+
+public:
+	Private(CameraBuffer *cameraBuffer,
+		buffer_handle_t camera3Buffer, int flags);
+	~Private();
+
+	unsigned int numPlanes() const;
+
+	Span<uint8_t> plane(unsigned int plane);
+};
+
+CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
+			       buffer_handle_t camera3Buffer, int flags)
+	: Extensible::Private(cameraBuffer)
 {
 	maps_.reserve(camera3Buffer->numFds);
 	error_ = 0;
@@ -42,6 +59,52 @@ CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)
 	}
 }
 
+CameraBuffer::Private::~Private()
+{
+}
+
+unsigned int CameraBuffer::Private::numPlanes() const
+{
+	return maps_.size();
+}
+
+Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
+{
+	if (plane >= maps_.size())
+		return {};
+
+	return maps_[plane];
+}
+
+CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)
+	: Extensible(new Private(this, camera3Buffer, flags))
+{
+}
+
 CameraBuffer::~CameraBuffer()
 {
 }
+
+bool CameraBuffer::isValid() const
+{
+	const Private *const d = LIBCAMERA_D_PTR();
+	return d->isValid();
+}
+
+unsigned int CameraBuffer::numPlanes() const
+{
+	const Private *const d = LIBCAMERA_D_PTR();
+	return d->numPlanes();
+}
+
+Span<const uint8_t> CameraBuffer::plane(unsigned int plane) const
+{
+	const Private *const d = LIBCAMERA_D_PTR();
+	return const_cast<Private *>(d)->plane(plane);
+}
+
+Span<uint8_t> CameraBuffer::plane(unsigned int plane)
+{
+	Private *const d = LIBCAMERA_D_PTR();
+	return d->plane(plane);
+}