[libcamera-devel] [PATCH v1] libcamera: framebuffer_allocator: Avoid double map lookup

[Laurent Pinchart]

Hi Barnabás,

Thank you for the patch.

On Sat, Nov 26, 2022 at 11:42:27PM +0000, Barnabás Pőcze via libcamera-devel wrote:
> Use `try_emplace()` on the map instead of `count()`
> and `operator[]` to avoid walking the tree twice.
> 
> Signed-off-by: Barnabás Pőcze <pobrn at protonmail.com>
> ---
>  src/libcamera/framebuffer_allocator.cpp | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/src/libcamera/framebuffer_allocator.cpp b/src/libcamera/framebuffer_allocator.cpp
> index 4df27cac..17c5db49 100644
> --- a/src/libcamera/framebuffer_allocator.cpp
> +++ b/src/libcamera/framebuffer_allocator.cpp
> @@ -88,12 +88,14 @@ FrameBufferAllocator::~FrameBufferAllocator()
>   */
>  int FrameBufferAllocator::allocate(Stream *stream)
>  {
> -	if (buffers_.count(stream)) {
> +	const auto &[ it, inserted ] = buffers_.try_emplace(stream);

No spaces within [ ... ]

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

No need to resubmit if you agree with this change, I'll fix when
applying.

> +
> +	if (!inserted) {
>  		LOG(Allocator, Error) << "Buffers already allocated for stream";
>  		return -EBUSY;
>  	}
> 
> -	int ret = camera_->exportFrameBuffers(stream, &buffers_[stream]);
> +	int ret = camera_->exportFrameBuffers(stream, &it->second);
>  	if (ret == -EINVAL)
>  		LOG(Allocator, Error)
>  			<< "Stream is not part of " << camera_->id()

-- 
Regards,

Laurent Pinchart