[libcamera-devel] [PATCH v3 2/3] android: camera_device: Use Camera3StreamConfig in configureStreams()

[Jacopo Mondi]

Hi Hiro,

On Mon, Dec 07, 2020 at 08:42:17AM +0000, Hirokazu Honda wrote:
> This uses Camera3StreamConfig in CameraDevice::configureStreams().

I would be slightly more verbose.

"Use the newly introduced Camera3StreamConfig to associate the
Android requested streams with the associated StreamConfiguration
in a vector of configurations.

This change prepares to sort the vector of configuration before using
it to configure the Camera and populate the streams_ vector.

No functional changes intended."

And the signed-off-by of course.
> ---
>  src/android/camera_device.cpp | 52 +++++++++++++++++++++--------------
>  1 file changed, 31 insertions(+), 21 deletions(-)
>
> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> index 09269d95..b7bf3d88 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -1240,6 +1240,9 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
>  	streams_.clear();
>  	streams_.reserve(stream_list->num_streams);
>
> +	std::vector<Camera3StreamConfig> streamConfigs;
> +	streamConfigs.reserve(stream_list->num_streams);
> +
>  	/* First handle all non-MJPEG streams. */
>  	camera3_stream_t *jpegStream = nullptr;
>  	for (unsigned int i = 0; i < stream_list->num_streams; ++i) {
> @@ -1270,14 +1273,12 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
>  			continue;
>  		}
>
> -		StreamConfiguration streamConfiguration;
> -		streamConfiguration.size = size;
> -		streamConfiguration.pixelFormat = format;
> -
> -		config_->addConfiguration(streamConfiguration);
> -		streams_.emplace_back(this, CameraStream::Type::Direct,
> -				      stream, config_->size() - 1);
> -		stream->priv = static_cast<void *>(&streams_.back());
> +		Camera3StreamConfig streamConfig;
> +		streamConfig.streams = { stream };
> +		streamConfig.types = { CameraStream::Type::Direct };
> +		streamConfig.config.size = size;
> +		streamConfig.config.pixelFormat = format;
> +		streamConfigs.push_back(std::move(streamConfig));

Nit: does this move help in any way with memory handling ? I mean,
I do expect the auto-generated move constructor of Camera3StreamConfig
not being able to magically move bits between the local variable and
the vector storage ? Am I wrong or what move() actually does is to
invalidate the local variable but copies data anyway in this case ?

We're talking about a tiny number of operations not in an hot-path, so
this i very minor, but I wonder if emplace() wouldn't do better (or
just a push_back() it it's equivalent to move()).

>  	}
>
>  	/* Now handle the MJPEG streams, adding a new stream if required. */
> @@ -1286,9 +1287,8 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
>  		int index = -1;
>
>  		/* Search for a compatible stream in the non-JPEG ones. */
> -		for (unsigned int i = 0; i < config_->size(); i++) {
> -			StreamConfiguration &cfg = config_->at(i);
> -
> +		for (size_t i = 0; i < streamConfigs.size(); ++i) {
> +			const auto &cfg = streamConfigs[i].config;
>  			/*
>  			 * \todo The PixelFormat must also be compatible with
>  			 * the encoder.
> @@ -1310,28 +1310,38 @@ int CameraDevice::configureStreams(camera3_stream_configuration_t *stream_list)
>  		 * introduce a new stream to satisfy the request requirements.
>  		 */
>  		if (index < 0) {
> -			StreamConfiguration streamConfiguration;
> -
>  			/*
>  			 * \todo The pixelFormat should be a 'best-fit' choice
>  			 * and may require a validation cycle. This is not yet
>  			 * handled, and should be considered as part of any
>  			 * stream configuration reworks.
>  			 */
> -			streamConfiguration.size.width = jpegStream->width;
> -			streamConfiguration.size.height = jpegStream->height;
> -			streamConfiguration.pixelFormat = formats::NV12;
> +			Camera3StreamConfig streamConfig;
> +			streamConfig.config.size.width = jpegStream->width;
> +			streamConfig.config.size.height = jpegStream->height;
> +			streamConfig.config.pixelFormat = formats::NV12;
> +			streamConfigs.push_back(std::move(streamConfig));
>
> -			LOG(HAL, Info) << "Adding " << streamConfiguration.toString()
> +			LOG(HAL, Info) << "Adding " << streamConfig.config.toString()
>  				       << " for MJPEG support";
>
>  			type = CameraStream::Type::Internal;
> -			config_->addConfiguration(streamConfiguration);
> -			index = config_->size() - 1;
> +			index = streamConfigs.size() - 1;
>  		}
>
> -		streams_.emplace_back(this, type, jpegStream, index);
> -		jpegStream->priv = static_cast<void *>(&streams_.back());
> +		streamConfigs[index].streams.push_back(jpegStream);
> +		streamConfigs[index].types.push_back(type);
> +	}
> +
> +	for (const auto &streamConfig : streamConfigs) {
> +		config_->addConfiguration(streamConfig.config);
> +		for (size_t i = 0; i < streamConfig.streams.size(); ++i) {
> +			camera3_stream_t *stream = streamConfig.streams[i];
> +			const CameraStream::Type type = streamConfig.types[i];
> +			streams_.emplace_back(this, type,
> +					      stream, config_->size() - 1);
> +			stream->priv = static_cast<void*>(&streams_.back());
> +		}

I like where this is going!
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Thanks
  j

>  	}
>
>  	switch (config_->validate()) {
> --
> 2.29.2.576.ga3fc446d84-goog