[libcamera-devel] [PATCH v3 09/10] android: camera_device: Send capture results inspecting the descriptor

[Umang Jain]

A Camera3RequestDescriptors is constructed and queued to descriptors_
queue as soon as an (incoming) capture request is received on the
libcamera HAL. The capture request is picked up by HAL, in order to run
it to completion. At completion, CameraDevice::requestComplete() gets
invoked and capture results are populated and ready to be sent back
to the framework.

All the data and framebuffers associated with the request are alive
and encapsulated inside this Camera3RequestDescriptor descriptor.
By inspecting the ProcessStatus on the descriptor, we can now send
capture results via the process_capture_result() callback.

Hence, introduce a new private member function sendCaptureResults()
which will be responsible to send capture results back to the
framework by inspecting the descriptor on the queue. In subsequent
commit, when the post processsor shall run async, sendCaptureResults()
can be called from the post-processor's thread for e.g.
streamProcessComplete() hence, introduce the mutex lock to avoid the
races.

Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
---
 src/android/camera_device.cpp | 47 +++++++++++++++++++++++++----------
 src/android/camera_device.h   |  4 +++
 2 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 4658e881..16ecdfc5 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1078,7 +1078,7 @@ 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 = {};
+	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_) {
@@ -1156,26 +1156,25 @@ void CameraDevice::requestComplete(Request *request)
 			continue;
 		}
 
+		if (cameraStream->type() == CameraStream::Type::Internal)
+			descriptor->internalBuffer_ = src;
+
 		descriptor->status_ = Camera3RequestDescriptor::ProcessStatus::Processing;
 
 		cameraStream->process(src, *buffer.buffer, descriptor);
-
-		/*
-		 * Return the FrameBuffer to the CameraStream now that we're
-		 * done processing it.
-		 */
-		if (cameraStream->type() == CameraStream::Type::Internal)
-			cameraStream->putBuffer(src);
+		return;
 	}
 
-	captureResult.result = descriptor->resultMetadata_->get();
-	callbacks_->process_capture_result(callbacks_, &captureResult);
-
-	descriptors_.pop_front();
+	/*
+	 * Mark the status on the descriptor as success as no processing
+	 * is neeeded.
+	 */
+	descriptor->status_ = Camera3RequestDescriptor::ProcessStatus::Success;
+	sendCaptureResults();
 }
 
 
-void CameraDevice::streamProcessingComplete([[maybe_unused]] CameraStream *cameraStream,
+void CameraDevice::streamProcessingComplete(CameraStream *cameraStream,
 					    Camera3RequestDescriptor *request)
 {
 	if (request->status_ == Camera3RequestDescriptor::ProcessStatus::Error) {
@@ -1190,6 +1189,28 @@ void CameraDevice::streamProcessingComplete([[maybe_unused]] CameraStream *camer
 				    CAMERA3_MSG_ERROR_BUFFER);
 		}
 	}
+
+	/*
+	 * Return the FrameBuffer to the CameraStream now that we're
+	 * done processing it.
+	 */
+	if (cameraStream->type() == CameraStream::Type::Internal)
+		cameraStream->putBuffer(request->internalBuffer_);
+
+	sendCaptureResults();
+}
+
+void CameraDevice::sendCaptureResults()
+{
+	Camera3RequestDescriptor *d = descriptors_.front().get();
+	if (d->status_ == Camera3RequestDescriptor::ProcessStatus::Processing ||
+	    d->status_ == Camera3RequestDescriptor::ProcessStatus::None)
+		return;
+
+	MutexLocker lock(descriptorsMutex_);
+	d->captureResult_.result = d->resultMetadata_->get();
+	callbacks_->process_capture_result(callbacks_, &(d->captureResult_));
+	descriptors_.pop_front();
 }
 
 std::string CameraDevice::logPrefix() const
diff --git a/src/android/camera_device.h b/src/android/camera_device.h
index 60c134dc..0bd570a1 100644
--- a/src/android/camera_device.h
+++ b/src/android/camera_device.h
@@ -56,6 +56,9 @@ struct Camera3RequestDescriptor {
 	std::unique_ptr<CaptureRequest> request_;
 	std::unique_ptr<CameraMetadata> resultMetadata_;
 
+	camera3_capture_result_t captureResult_ = {};
+	libcamera::FrameBuffer *internalBuffer_;
+
 	ProcessStatus status_;
 };
 
@@ -118,6 +121,7 @@ private:
 	int processControls(Camera3RequestDescriptor *descriptor);
 	std::unique_ptr<CameraMetadata> getResultMetadata(
 		const Camera3RequestDescriptor *descriptor) const;
+	void sendCaptureResults();
 
 	unsigned int id_;
 	camera3_device_t camera3Device_;
-- 
2.31.1