android: camera_request: Don't embed full camera3_stream_buffer_t

The camera3_stream_buffer_t structure is meant to communicate between
the camera service and the HAL. They are short-live structures that
don't outlive the .process_capture_request() operation (when queuing
requests) or the .process_capture_result() callback.

We currently store copies of the camera3_stream_buffer_t passed to
.process_capture_request() in Camera3RequestDescriptor::StreamBuffer to
store the structure members that the HAL need, and reuse them when
calling the .process_capture_result() callback. This is conceptually not
right, as the camera3_stream_buffer_t pass to the callback are not the
same objects as the ones received in .process_capture_request().

Store individual fields of the camera3_stream_buffer_t in StreamBuffer
instead of copying the whole structure. This gives the HAL full control
of how data is stored, and properly decouples request queueing from
result reporting.

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

1 files changed, 15 insertions, 4 deletions

diff --git a/src/android/camera_request.cpp b/src/android/camera_request.cpp
index 614baed4..faa85ada 100644
--- a/src/android/camera_request.cpp
+++ b/src/android/camera_request.cpp
@@ -7,6 +7,8 @@
 
 #include "camera_request.h"
 
+#include <libcamera/base/span.h>
+
 using namespace libcamera;
 
 /*
@@ -22,11 +24,20 @@ Camera3RequestDescriptor::Camera3RequestDescriptor(
 	frameNumber_ = camera3Request->frame_number;
 
 	/* Copy the camera3 request stream information for later access. */
-	const uint32_t numBuffers = camera3Request->num_output_buffers;
+	const Span<const camera3_stream_buffer_t> buffers{
+		camera3Request->output_buffers,
+		camera3Request->num_output_buffers
+	};
+
+	buffers_.reserve(buffers.size());
+
+	for (const camera3_stream_buffer_t &buffer : buffers) {
+		CameraStream *stream =
+			static_cast<CameraStream *>(buffer.stream->priv);
 
-	buffers_.resize(numBuffers);
-	for (uint32_t i = 0; i < numBuffers; i++)
-		buffers_[i].buffer = camera3Request->output_buffers[i];
+		buffers_.push_back({ stream, buffer.buffer, nullptr,
+				     buffer.acquire_fence, Status::Pending });
+	}
 
 	/* Clone the controls associated with the camera3 request. */
 	settings_ = CameraMetadata(camera3Request->settings);