android: Track and notify post processing of streams

Notify that the post processing for a request has been completed,
via a signal. The signal is emitted with a context pointer along with
status of the buffer. The function CameraDevice::streamProcessingComplete()
will finally set the status on the request descriptor and complete the
descriptor if all the streams requiring post processing are completed.
If buffer status obtained is in error state, notify the status to the
framework and set the overall error status on the descriptor via
setBufferStatus().

We need to track the number of streams requiring post-processing
per Camera3RequestDescriptor (i.e. per capture request). Introduce
a std::map to track the post-processing of streams. The nodes
are dropped from the map when a particular stream post processing
is completed (or on error paths). A std::map is selected for tracking
post-processing requests, since we will move post-processing to be
asynchronous in subsequent commits. A vector or queue will not be
suitable as the sequential order of post-processing completion
of various requests won't be guaranteed then.

A streamsProcessMutex_ has been introduced here as well, which will be
applicable to guard access to descriptor's pendingStreamsToProcess_ when
post-processing is moved to be asynchronous in subsequent commits.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/src/android/camera_request.h b/src/android/camera_request.h
index ebe2e89d..cfafa445 100644
--- a/src/android/camera_request.h
+++ b/src/android/camera_request.h
@@ -7,7 +7,9 @@
 #ifndef __ANDROID_CAMERA_REQUEST_H__
 #define __ANDROID_CAMERA_REQUEST_H__
 
+#include <map>
 #include <memory>
+#include <mutex>
 #include <vector>
 
 #include <libcamera/base/class.h>
@@ -43,6 +45,10 @@ public:
 		Camera3RequestDescriptor *request;
 	};
 
+	/* Keeps track of streams requiring post-processing. */
+	std::map<CameraStream *, StreamBuffer *> pendingStreamsToProcess_;
+	std::mutex streamsProcessMutex_;
+
 	Camera3RequestDescriptor(libcamera::Camera *camera,
 				 const camera3_capture_request_t *camera3Request);
 	~Camera3RequestDescriptor();