[libcamera-devel] [PATCH v2 1/5] android: camera_stream: Add sourceStream

[Umang Jain]

Hi Paul,

Thank you for the patch

On 5/27/22 11:34, Paul Elder via libcamera-devel wrote:
> From: Hirokazu Honda <hiroh at chromium.org>
>
> Add to the CameraStream class a sourceStream field, which for streams
> of type Mapped contains a reference to the stream which produces the
> actual image data.


I think some re-pharsing would be nice to better comprehend the changes.

"Add a sourceStream field to the CameraStream class, meant to contain a 
reference
of a direct stream (which produces actual image data) for 
CameraStream::Mapped
stream types."

>
> The sourceStream of mapped streams will be used in later patches to make
> sure for each Mapped stream at least one libcamera::Stream is queued to
> the libcamera::Camera.
>
> Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
> ---
> Changes in v2:
> - fix whitespace
> ---
>   src/android/camera_device.cpp | 8 +++++++-
>   src/android/camera_stream.cpp | 6 ++++--
>   src/android/camera_stream.h   | 6 +++++-
>   3 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> index 8e804d4d..20599665 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -681,10 +681,16 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
>   	for (const auto &streamConfig : streamConfigs) {
>   		config->addConfiguration(streamConfig.config);
>   
> +		CameraStream *sourceStream = nullptr;
>   		for (auto &stream : streamConfig.streams) {
>   			streams_.emplace_back(this, config.get(), stream.type,
> -					      stream.stream, config->size() - 1);
> +					      stream.stream, sourceStream,
> +					      config->size() - 1);
>   			stream.stream->priv = static_cast<void *>(&streams_.back());
> +
> +			/* Mapped streams are always associated with a Direct one. */
> +			if (stream.type == CameraStream::Type::Direct)


This doesn't look right to me, why are we setting sourceStream field for 
a direct stream type?

Shouldn't be it something like:

+            if (stream.type == CameraStream::Type::Mapped)
+                      sourceStream = ....

instead?

> +				sourceStream = &streams_.back();
>   		}
>   	}
>   
> diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> index 94f1884c..154e088e 100644
> --- a/src/android/camera_stream.cpp
> +++ b/src/android/camera_stream.cpp
> @@ -52,9 +52,11 @@ LOG_DECLARE_CATEGORY(HAL)
>   
>   CameraStream::CameraStream(CameraDevice *const cameraDevice,
>   			   CameraConfiguration *config, Type type,
> -			   camera3_stream_t *camera3Stream, unsigned int index)
> +			   camera3_stream_t *camera3Stream,
> +			   CameraStream *const sourceStream, unsigned int index)
>   	: cameraDevice_(cameraDevice), config_(config), type_(type),
> -	  camera3Stream_(camera3Stream), index_(index)
> +	  camera3Stream_(camera3Stream), sourceStream_(sourceStream),
> +	  index_(index)
>   {
>   }
>   
> diff --git a/src/android/camera_stream.h b/src/android/camera_stream.h
> index f9504462..4c5078b2 100644
> --- a/src/android/camera_stream.h
> +++ b/src/android/camera_stream.h
> @@ -114,7 +114,9 @@ public:
>   	};
>   	CameraStream(CameraDevice *const cameraDevice,
>   		     libcamera::CameraConfiguration *config, Type type,
> -		     camera3_stream_t *camera3Stream, unsigned int index);
> +		     camera3_stream_t *camera3Stream,
> +		     CameraStream *const sourceStream,
> +		     unsigned int index);
>   	CameraStream(CameraStream &&other);
>   	~CameraStream();
>   
> @@ -122,6 +124,7 @@ public:
>   	camera3_stream_t *camera3Stream() const { return camera3Stream_; }
>   	const libcamera::StreamConfiguration &configuration() const;
>   	libcamera::Stream *stream() const;
> +	CameraStream *sourceStream() const { return sourceStream_; }
>   
>   	int configure();
>   	int process(Camera3RequestDescriptor::StreamBuffer *streamBuffer);
> @@ -167,6 +170,7 @@ private:
>   	const libcamera::CameraConfiguration *config_;
>   	const Type type_;
>   	camera3_stream_t *camera3Stream_;
> +	CameraStream *const sourceStream_;
>   	const unsigned int index_;
>   
>   	std::unique_ptr<PlatformFrameBufferAllocator> allocator_;