android: camera_device: Build capture_result dynamically

The camera3_capture_result_t is only needed to convey capture results to
the camera service through the process_capture_result() callback.
There's no need to store it in the Camera3RequestDescriptor. Build it
dynamically in CameraDevice::sendCaptureResults() instead.

This requires storing the result metadata created in
CameraDevice::requestComplete() in the Camera3RequestDescriptor. A side
effect of this change is that the request metadata lifetime will match
the Camera3RequestDescriptor instead of being destroyed at the end of
requestComplete(). This will be needed to support asynchronous
post-processing, where the request completion will be signaled to the
camera service asynchronously from requestComplete().

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

src/android/camera_device.cpp

@@ -801,19 +801,11 @@ void CameraDevice::abortRequest(Camera3RequestDescriptor *descriptor) const
 {
 	notifyError(descriptor->frameNumber_, nullptr, CAMERA3_MSG_ERROR_REQUEST);
 
-	camera3_capture_result_t &result = descriptor->captureResult_;
+	for (auto &buffer : descriptor->buffers_) {
-	result.num_output_buffers = descriptor->buffers_.size();
+		buffer.release_fence = buffer.acquire_fence;
-	result.frame_number = descriptor->frameNumber_;
-	result.partial_result = 0;
-
-	std::vector<camera3_stream_buffer_t> resultBuffers(result.num_output_buffers);
-	for (auto [i, buffer] : utils::enumerate(resultBuffers)) {
-		buffer = descriptor->buffers_[i];
-		buffer.release_fence = descriptor->buffers_[i].acquire_fence;
 		buffer.acquire_fence = -1;
 		buffer.status = CAMERA3_BUFFER_STATUS_ERROR;
 	}
-	result.output_buffers = resultBuffers.data();
 
 	descriptor->status_ = Camera3RequestDescriptor::Status::Error;
 }
@@ -1062,9 +1054,6 @@ void CameraDevice::requestComplete(Request *request)
 	 * The buffer status is set to OK and later changed to ERROR if
 	 * post-processing/compression fails.
 	 */
-	camera3_capture_result_t &captureResult = descriptor->captureResult_;
-	captureResult.frame_number = descriptor->frameNumber_;
-	captureResult.num_output_buffers = descriptor->buffers_.size();
 	for (camera3_stream_buffer_t &buffer : descriptor->buffers_) {
 		CameraStream *cameraStream =
 			static_cast<CameraStream *>(buffer.stream->priv);
@@ -1085,8 +1074,6 @@ void CameraDevice::requestComplete(Request *request)
 		buffer.release_fence = -1;
 		buffer.status = CAMERA3_BUFFER_STATUS_OK;
 	}
-	captureResult.output_buffers = descriptor->buffers_.data();
-	captureResult.partial_result = 1;
 
 	/*
 	 * If the Request has failed, abort the request by notifying the error
@@ -1100,7 +1087,6 @@ void CameraDevice::requestComplete(Request *request)
 		notifyError(descriptor->frameNumber_, nullptr,
 			    CAMERA3_MSG_ERROR_REQUEST);
 
-		captureResult.partial_result = 0;
 		for (camera3_stream_buffer_t &buffer : descriptor->buffers_) {
 			/*
 			 * Signal to the framework it has to handle fences that
@@ -1137,12 +1123,17 @@ void CameraDevice::requestComplete(Request *request)
 	 * Notify if the metadata generation has failed, but continue processing
 	 * buffers and return an empty metadata pack.
 	 */
-	std::unique_ptr<CameraMetadata> resultMetadata = getResultMetadata(*descriptor);
+	descriptor->resultMetadata_ = getResultMetadata(*descriptor);
-	if (!resultMetadata) {
+	if (!descriptor->resultMetadata_) {
 		notifyError(descriptor->frameNumber_, nullptr, CAMERA3_MSG_ERROR_RESULT);
 
-		/* The camera framework expects an empty metadata pack on error. */
+		/*
-		resultMetadata = std::make_unique<CameraMetadata>(0, 0);
+		 * The camera framework expects an empty metadata pack on error.
+		 *
+		 * \todo Check that the post-processor code handles this situation
+		 * correctly.
+		 */
+		descriptor->resultMetadata_ = std::make_unique<CameraMetadata>(0, 0);
 	}
 
 	/* Handle post-processing. */
@@ -1164,7 +1155,7 @@ void CameraDevice::requestComplete(Request *request)
 
 		int ret = cameraStream->process(*src, buffer,
 						descriptor->settings_,
-						resultMetadata.get());
+						descriptor->resultMetadata_.get());
 		/*
 		 * Return the FrameBuffer to the CameraStream now that we're
 		 * done processing it.
@@ -1179,7 +1170,6 @@ void CameraDevice::requestComplete(Request *request)
 		}
 	}
 
-	captureResult.result = resultMetadata->get();
 	descriptor->status_ = Camera3RequestDescriptor::Status::Success;
 	sendCaptureResults();
 }
@@ -1197,8 +1187,20 @@ void CameraDevice::sendCaptureResults()
 		 * impact on performance which should be measured.
 		 */
 		lock.unlock();
-		callbacks_->process_capture_result(callbacks_,
+
-						   &descriptor->captureResult_);
+		camera3_capture_result_t captureResult = {};
+
+		captureResult.frame_number = descriptor->frameNumber_;
+		if (descriptor->resultMetadata_)
+			captureResult.result = descriptor->resultMetadata_->get();
+		captureResult.num_output_buffers = descriptor->buffers_.size();
+		captureResult.output_buffers = descriptor->buffers_.data();
+
+		if (descriptor->status_ == Camera3RequestDescriptor::Status::Success)
+			captureResult.partial_result = 1;
+
+		callbacks_->process_capture_result(callbacks_, &captureResult);
+
 		lock.lock();
 	}
 }

src/android/camera_request.h

@@ -40,8 +40,8 @@ public:
 	std::vector<std::unique_ptr<libcamera::FrameBuffer>> frameBuffers_;
 	CameraMetadata settings_;
 	std::unique_ptr<CaptureRequest> request_;
+	std::unique_ptr<CameraMetadata> resultMetadata_;
 
-	camera3_capture_result_t captureResult_ = {};
 	Status status_ = Status::Pending;
 
 private: