[libcamera-devel] [PATCH 12/15] android: camera_stream: Add methods to get/put buffers

[Laurent Pinchart]

Hi Jacopo,

Thank you for the patch.

On Mon, Oct 05, 2020 at 01:46:46PM +0300, Laurent Pinchart wrote:
> From: Jacopo Mondi <jacopo at jmondi.org>
> 
> Add two methods to the CameraStream class to get and put FrameBuffer
> pointers from the pool of allocated buffers.

You may want to explain in the commit message that you're actually
creating a pool of buffers, and what it is used for.

> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  src/android/camera_stream.cpp | 35 +++++++++++++++++++++++++++++++++--
>  src/android/camera_stream.h   |  4 ++++
>  2 files changed, 37 insertions(+), 2 deletions(-)
> 
> diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
> index dbde1e786300..c4b727eee63e 100644
> --- a/src/android/camera_stream.cpp
> +++ b/src/android/camera_stream.cpp
> @@ -19,21 +19,24 @@ LOG_DECLARE_CATEGORY(HAL);
>  CameraStream::CameraStream(CameraDevice *cameraDev, Type type,
>  			   camera3_stream_t *androidStream, unsigned int index)
>  	: cameraDevice_(cameraDev), type_(type), androidStream_(androidStream),
> -	  index_(index), encoder_(nullptr), allocator_(nullptr)
> +	  index_(index), encoder_(nullptr), allocator_(nullptr), mutex_(nullptr)
>  {
>  	config_ = cameraDevice_->cameraConfiguration();
>  
>  	if (type_ == Type::Internal || type_ == Type::Mapped)
>  		encoder_ = new EncoderLibJpeg();
>  
> -	if (type == Type::Internal)
> +	if (type == Type::Internal) {
>  		allocator_ = new FrameBufferAllocator(cameraDevice_->camera());
> +		mutex_ = new std::mutex();

I'd embed this in the class.

> +	}
>  }
>  
>  CameraStream::~CameraStream()
>  {
>  	delete encoder_;
>  	delete allocator_;
> +	delete mutex_;
>  }
>  
>  const StreamConfiguration &CameraStream::streamConfiguration() const
> @@ -135,3 +138,31 @@ int CameraStream::process(libcamera::FrameBuffer *source, MappedCamera3Buffer *d
>  
>  	return 0;
>  }
> +
> +FrameBuffer *CameraStream::getBuffer()
> +{
> +	if (!allocator_)
> +		return nullptr;
> +
> +	std::lock_guard<std::mutex> locker(*mutex_);
> +
> +	if (buffers_.empty()) {
> +		LOG(HAL, Error) << "Buffer underrun";
> +		return nullptr;
> +	}
> +
> +	FrameBuffer *buffer = buffers_.back();
> +	buffers_.pop_back();
> +
> +	return buffer;
> +}
> +
> +void CameraStream::putBuffer(libcamera::FrameBuffer *buffer)
> +{
> +	if (!allocator_)
> +		return;
> +
> +	std::lock_guard<std::mutex> locker(*mutex_);
> +
> +	buffers_.push_back(buffer);
> +}
> diff --git a/src/android/camera_stream.h b/src/android/camera_stream.h
> index c6ff79230b7e..b79a97606c60 100644
> --- a/src/android/camera_stream.h
> +++ b/src/android/camera_stream.h
> @@ -8,6 +8,7 @@
>  #define __ANDROID_CAMERA_STREAM_H__
>  
>  #include <memory>
> +#include <mutex>
>  #include <vector>
>  
>  #include <hardware/camera3.h>
> @@ -127,6 +128,8 @@ public:
>  	int process(libcamera::FrameBuffer *source,
>  		    MappedCamera3Buffer *dest,
>  		    CameraMetadata *metadata);
> +	libcamera::FrameBuffer *getBuffer();
> +	void putBuffer(libcamera::FrameBuffer *buffer);
>  
>  private:
>  	CameraDevice *cameraDevice_;
> @@ -143,6 +146,7 @@ private:
>  	Encoder *encoder_;
>  	libcamera::FrameBufferAllocator *allocator_;
>  	std::vector<libcamera::FrameBuffer *> buffers_;
> +	std::mutex *mutex_;
>  };
>  
>  #endif /* __ANDROID_CAMERA_STREAM__ */

-- 
Regards,

Laurent Pinchart