[libcamera-devel] [RFC] libcamera: buffer: Remove copyFrom()

[Laurent Pinchart]

Hi Niklas,

Thank you for the patch.

On Mon, Sep 21, 2020 at 08:32:05PM +0200, Niklas Söderlund wrote:
> There are no user left of the copyFrom() operation, remove it.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
>  include/libcamera/buffer.h |  2 --
>  src/libcamera/buffer.cpp   | 59 --------------------------------------
>  2 files changed, 61 deletions(-)
> ---
> 
> Hello,
> 
> I'm not sure it's wise to leave this operation in the code while we have 
> no users. But I do fear we might need it the future, but as we don't use 
> or test it I'm sure we will have modified FrameBuffer enough to make 
> this incomplete at that that so I think it's best to remove it. What do 
> you guys think?

Drop it :-)

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

We can always bring code back if needed.

> diff --git a/include/libcamera/buffer.h b/include/libcamera/buffer.h
> index 6bb2e4f8558f03ac..a26c8927d37a812e 100644
> --- a/include/libcamera/buffer.h
> +++ b/include/libcamera/buffer.h
> @@ -57,8 +57,6 @@ public:
>  
>  	unsigned int cookie() const { return cookie_; }
>  	void setCookie(unsigned int cookie) { cookie_ = cookie; }
> -
> -	int copyFrom(const FrameBuffer *src);
>  private:
>  	friend class Request; /* Needed to update request_. */
>  	friend class V4L2VideoDevice; /* Needed to update metadata_. */
> diff --git a/src/libcamera/buffer.cpp b/src/libcamera/buffer.cpp
> index 03f628e8b585a1f9..75b2693281a74cdc 100644
> --- a/src/libcamera/buffer.cpp
> +++ b/src/libcamera/buffer.cpp
> @@ -226,65 +226,6 @@ FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie)
>   * core never modifies the buffer cookie.
>   */
>  
> -/**
> - * \brief Copy the contents from another buffer
> - * \param[in] src FrameBuffer to copy
> - *
> - * Copy the buffer contents and metadata from \a src to this buffer. The
> - * destination FrameBuffer shall have the same number of planes as the source
> - * buffer, and each destination plane shall be larger than or equal to the
> - * corresponding source plane.
> - *
> - * The complete metadata of the source buffer is copied to the destination
> - * buffer. If an error occurs during the copy, the destination buffer's metadata
> - * status is set to FrameMetadata::FrameError, and other metadata fields are not
> - * modified.
> - *
> - * The operation is performed using memcpy() so is very slow, users needs to
> - * consider this before copying buffers.
> - *
> - * \return 0 on success or a negative error code otherwise
> - */
> -int FrameBuffer::copyFrom(const FrameBuffer *src)
> -{
> -	if (planes_.size() != src->planes_.size()) {
> -		LOG(Buffer, Error) << "Different number of planes";
> -		metadata_.status = FrameMetadata::FrameError;
> -		return -EINVAL;
> -	}
> -
> -	for (unsigned int i = 0; i < planes_.size(); i++) {
> -		if (planes_[i].length < src->planes_[i].length) {
> -			LOG(Buffer, Error) << "Plane " << i << " is too small";
> -			metadata_.status = FrameMetadata::FrameError;
> -			return -EINVAL;
> -		}
> -	}
> -
> -	MappedFrameBuffer source(src, PROT_READ);
> -	MappedFrameBuffer destination(this, PROT_WRITE);
> -
> -	if (!source.isValid()) {
> -		LOG(Buffer, Error) << "Failed to map source planes";
> -		return -EINVAL;
> -	}
> -
> -	if (!destination.isValid()) {
> -		LOG(Buffer, Error) << "Failed to map destination planes";
> -		return -EINVAL;
> -	}
> -
> -	for (unsigned int i = 0; i < planes_.size(); i++) {
> -		memcpy(destination.maps()[i].data(),
> -		       source.maps()[i].data(),
> -		       source.maps()[i].size());
> -	}
> -
> -	metadata_ = src->metadata_;
> -
> -	return 0;
> -}
> -
>  /**
>   * \class MappedBuffer
>   * \brief Provide an interface to support managing memory mapped buffers

-- 
Regards,

Laurent Pinchart