[libcamera-devel] [PATCH v3 2/8] libcamera: request: Add Request::cancel()

[Niklas Söderlund]

Hi Jacopo,

Thanks for your patch.

On 2021-05-21 17:42:21 +0200, Jacopo Mondi wrote:
> Add a cancel() function to the Request class that allows to forcefully
> complete the request and its associated buffers in error state.
> 
> Only pending requests can be forcefully cancelled. Enforce that
> by asserting the request state to be RequestPending.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> Reviewed-by: Hirokazu Honda <hiroh at chromium.org>

Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

> ---
>  .../libcamera/internal/tracepoints/request.tp |  8 ++++++
>  include/libcamera/request.h                   |  1 +
>  src/libcamera/request.cpp                     | 28 +++++++++++++++++++
>  3 files changed, 37 insertions(+)
> 
> diff --git a/include/libcamera/internal/tracepoints/request.tp b/include/libcamera/internal/tracepoints/request.tp
> index 9e872951374d..9c841b97438a 100644
> --- a/include/libcamera/internal/tracepoints/request.tp
> +++ b/include/libcamera/internal/tracepoints/request.tp
> @@ -66,6 +66,14 @@ TRACEPOINT_EVENT_INSTANCE(
>  	)
>  )
>  
> +TRACEPOINT_EVENT_INSTANCE(
> +	libcamera,
> +	request,
> +	request_cancel,
> +	TP_ARGS(
> +		libcamera::Request *, req
> +	)
> +)
>  
>  TRACEPOINT_EVENT(
>  	libcamera,
> diff --git a/include/libcamera/request.h b/include/libcamera/request.h
> index 4cf5ff3f7d3b..5596901ddd8e 100644
> --- a/include/libcamera/request.h
> +++ b/include/libcamera/request.h
> @@ -65,6 +65,7 @@ private:
>  	friend class PipelineHandler;
>  
>  	void complete();
> +	void cancel();
>  
>  	bool completeBuffer(FrameBuffer *buffer);
>  
> diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
> index ce2dd7b17f10..69b2d0172e3d 100644
> --- a/src/libcamera/request.cpp
> +++ b/src/libcamera/request.cpp
> @@ -292,6 +292,34 @@ void Request::complete()
>  	LIBCAMERA_TRACEPOINT(request_complete, this);
>  }
>  
> +/**
> + * \brief Cancel a queued request
> + *
> + * Mark the request and its associated buffers as cancelled and complete it.
> + *
> + * Set each pending buffer in error state and emit the buffer completion signal
> + * before completing the Request.
> + */
> +void Request::cancel()
> +{
> +	LIBCAMERA_TRACEPOINT(request_cancel, this);
> +
> +	ASSERT(status_ == RequestPending);
> +
> +	/*
> +	 * We can't simply loop and call completeBuffer() as the erase() call
> +	 * invalidates pointers and iterators, so we have to manually cancel the
> +	 * buffer from the pending buffers list.
> +	 */
> +	for (auto buffer = pending_.begin(); buffer != pending_.end();) {
> +		(*buffer)->cancel();
> +		camera_->bufferCompleted.emit(this, *buffer);
> +		buffer = pending_.erase(buffer);
> +	}
> +
> +	cancelled_ = true;
> +}
> +
>  /**
>   * \brief Complete a buffer for the request
>   * \param[in] buffer The buffer that has completed
> -- 
> 2.31.1
> 

-- 
Regards,
Niklas Söderlund