[libcamera-devel] [RFC PATCH v1 08/12] libcamera: framebuffer: Prevent modifying the number of metadata planes

Kieran Bingham kieran.bingham at ideasonboard.com
Thu Sep 2 12:03:47 CEST 2021



On 02/09/2021 05:22, Laurent Pinchart wrote:
> The number of metadata planes should always match the number of frame
> buffer planes. Enforce this by making the vector private and providing
> accessor functions.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  include/libcamera/framebuffer.h    | 10 +++++++++-
>  src/cam/camera_session.cpp         |  4 ++--
>  src/cam/file_sink.cpp              |  2 +-
>  src/libcamera/framebuffer.cpp      | 12 +++++++++---
>  src/libcamera/v4l2_videodevice.cpp | 14 +++++++-------
>  src/qcam/main_window.cpp           |  2 +-
>  src/qcam/viewfinder_gl.cpp         |  2 +-
>  src/qcam/viewfinder_qt.cpp         |  2 +-
>  src/v4l2/v4l2_camera_proxy.cpp     |  2 +-
>  9 files changed, 32 insertions(+), 18 deletions(-)
> 
> diff --git a/include/libcamera/framebuffer.h b/include/libcamera/framebuffer.h
> index fd68ed0a139d..7f2f176af691 100644
> --- a/include/libcamera/framebuffer.h
> +++ b/include/libcamera/framebuffer.h
> @@ -13,6 +13,7 @@
>  #include <vector>
>  
>  #include <libcamera/base/class.h>
> +#include <libcamera/base/span.h>
>  
>  #include <libcamera/file_descriptor.h>
>  
> @@ -34,7 +35,14 @@ struct FrameMetadata {
>  	Status status;
>  	unsigned int sequence;
>  	uint64_t timestamp;
> -	std::vector<Plane> planes;
> +
> +	Span<Plane> planes() { return planes_; }
> +	Span<const Plane> planes() const { return planes_; }

Returning a span here is nice.

This likely causes compile breakage for any external app.

I know we're not ABI/API stable, but I wonder if we should highlight
when we do cause breakage somehow, perhaps in the commit message at
least, as we already have external users who we might want to notify.


> +
> +private:
> +	friend class FrameBuffer;
> +
> +	std::vector<Plane> planes_;
>  };
>  
>  class FrameBuffer final : public Extensible
> diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp
> index 60d640f2b15c..32a373a99b72 100644
> --- a/src/cam/camera_session.cpp
> +++ b/src/cam/camera_session.cpp
> @@ -374,9 +374,9 @@ void CameraSession::processRequest(Request *request)
>  		     << " bytesused: ";
>  
>  		unsigned int nplane = 0;
> -		for (const FrameMetadata::Plane &plane : metadata.planes) {
> +		for (const FrameMetadata::Plane &plane : metadata.planes()) {
>  			info << plane.bytesused;
> -			if (++nplane < metadata.planes.size())
> +			if (++nplane < metadata.planes().size())
>  				info << "/";
>  		}
>  	}
> diff --git a/src/cam/file_sink.cpp b/src/cam/file_sink.cpp
> index 0b529e3eb767..0fc7d621f50b 100644
> --- a/src/cam/file_sink.cpp
> +++ b/src/cam/file_sink.cpp
> @@ -110,7 +110,7 @@ void FileSink::writeBuffer(const Stream *stream, FrameBuffer *buffer)
>  
>  	for (unsigned int i = 0; i < buffer->planes().size(); ++i) {
>  		const FrameBuffer::Plane &plane = buffer->planes()[i];
> -		const FrameMetadata::Plane &meta = buffer->metadata().planes[i];
> +		const FrameMetadata::Plane &meta = buffer->metadata().planes()[i];
>  
>  		uint8_t *data = planeData_[&plane];
>  		unsigned int length = std::min(meta.bytesused, plane.length);
> diff --git a/src/libcamera/framebuffer.cpp b/src/libcamera/framebuffer.cpp
> index c1529dfb0ad1..83cf7b83d182 100644
> --- a/src/libcamera/framebuffer.cpp
> +++ b/src/libcamera/framebuffer.cpp
> @@ -91,8 +91,14 @@ LOG_DEFINE_CATEGORY(Buffer)
>   */
>  
>  /**
> - * \var FrameMetadata::planes
> - * \brief Array of per-plane metadata
> + * \fn FrameMetadata::planes()
> + * \copydoc FrameMetadata::planes() const
> + */
> +
> +/**
> + * \fn FrameMetadata::planes() const
> + * \brief Retrieve the array of per-plane metadata
> + * \return The array of per-plane metadata
>   */
>  
>  /**
> @@ -210,7 +216,7 @@ FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie)
>  	: Extensible(std::make_unique<Private>()), planes_(planes),
>  	  cookie_(cookie)
>  {
> -	metadata_.planes.resize(planes_.size());
> +	metadata_.planes_.resize(planes_.size());
>  
>  	unsigned int offset = 0;
>  
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index a51971879e75..82ddaed3656f 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -1485,14 +1485,14 @@ int V4L2VideoDevice::queueBuffer(FrameBuffer *buffer)
>  
>  		if (multiPlanar) {
>  			unsigned int nplane = 0;
> -			for (const FrameMetadata::Plane &plane : metadata.planes) {
> +			for (const FrameMetadata::Plane &plane : metadata.planes()) {
>  				v4l2Planes[nplane].bytesused = plane.bytesused;
>  				v4l2Planes[nplane].length = buffer->planes()[nplane].length;
>  				nplane++;
>  			}
>  		} else {
> -			if (metadata.planes.size())
> -				buf.bytesused = metadata.planes[0].bytesused;
> +			if (metadata.planes().size())
> +				buf.bytesused = metadata.planes()[0].bytesused;
>  		}
>  
>  		buf.sequence = metadata.sequence;
> @@ -1587,17 +1587,17 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer()
>  				    + buf.timestamp.tv_usec * 1000ULL;
>  
>  	if (multiPlanar) {
> -		if (buf.length > buffer->metadata_.planes.size()) {
> +		if (buf.length > buffer->metadata_.planes().size()) {
>  			LOG(V4L2, Error)
>  				<< "Invalid number of planes (" << buf.length
> -				<< " != " << buffer->metadata_.planes.size() << ")";
> +				<< " != " << buffer->metadata_.planes().size() << ")";
>  			return nullptr;
>  		}
>  
>  		for (unsigned int nplane = 0; nplane < buf.length; nplane++)
> -			buffer->metadata_.planes[nplane].bytesused = planes[nplane].bytesused;
> +			buffer->metadata_.planes()[nplane].bytesused = planes[nplane].bytesused;
>  	} else {
> -		buffer->metadata_.planes[0].bytesused = buf.bytesused;
> +		buffer->metadata_.planes()[0].bytesused = buf.bytesused;
>  	}
>  
>  	return buffer;
> diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
> index 1536b2b5bd66..ac853e360aea 100644
> --- a/src/qcam/main_window.cpp
> +++ b/src/qcam/main_window.cpp
> @@ -756,7 +756,7 @@ void MainWindow::processViewfinder(FrameBuffer *buffer)
>  
>  	qDebug().noquote()
>  		<< QString("seq: %1").arg(metadata.sequence, 6, 10, QLatin1Char('0'))
> -		<< "bytesused:" << metadata.planes[0].bytesused
> +		<< "bytesused:" << metadata.planes()[0].bytesused
>  		<< "timestamp:" << metadata.timestamp
>  		<< "fps:" << Qt::fixed << qSetRealNumberPrecision(2) << fps;
>  
> diff --git a/src/qcam/viewfinder_gl.cpp b/src/qcam/viewfinder_gl.cpp
> index 40226601f9fd..d2ef036974f4 100644
> --- a/src/qcam/viewfinder_gl.cpp
> +++ b/src/qcam/viewfinder_gl.cpp
> @@ -125,7 +125,7 @@ void ViewFinderGL::render(libcamera::FrameBuffer *buffer,
>  	/*
>  	 * \todo Get the stride from the buffer instead of computing it naively
>  	 */
> -	stride_ = buffer->metadata().planes[0].bytesused / size_.height();
> +	stride_ = buffer->metadata().planes()[0].bytesused / size_.height();

Can this be obtained from the PixelFormatInfo now ?
or do we still not expose that to applications...

Anyway, that's likely a change on top even if we could to solve the \todo.

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>


>  	update();
>  	buffer_ = buffer;
>  }
> diff --git a/src/qcam/viewfinder_qt.cpp b/src/qcam/viewfinder_qt.cpp
> index efa1d412584b..a0bf99b0b522 100644
> --- a/src/qcam/viewfinder_qt.cpp
> +++ b/src/qcam/viewfinder_qt.cpp
> @@ -87,7 +87,7 @@ void ViewFinderQt::render(libcamera::FrameBuffer *buffer,
>  	}
>  
>  	unsigned char *memory = mem.data();
> -	size_t size = buffer->metadata().planes[0].bytesused;
> +	size_t size = buffer->metadata().planes()[0].bytesused;
>  
>  	{
>  		QMutexLocker locker(&mutex_);
> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> index 8d8ee395954f..68e47ee81834 100644
> --- a/src/v4l2/v4l2_camera_proxy.cpp
> +++ b/src/v4l2/v4l2_camera_proxy.cpp
> @@ -212,7 +212,7 @@ void V4L2CameraProxy::updateBuffers()
>  
>  		switch (fmd.status) {
>  		case FrameMetadata::FrameSuccess:
> -			buf.bytesused = fmd.planes[0].bytesused;
> +			buf.bytesused = fmd.planes()[0].bytesused;
>  			buf.field = V4L2_FIELD_NONE;
>  			buf.timestamp.tv_sec = fmd.timestamp / 1000000000;
>  			buf.timestamp.tv_usec = fmd.timestamp % 1000000;
> 


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