[PATCH 4/4] gstreamer: Split metadata controls into new member

[Jaslo Ziska]

When the libcamerasrc element is stopped and started again, the
GstCameraControls::setCamera() function is called, but now it is
populated with metadata returned by the previous requests. Because
GstCameraControls::setCamera() filters the controls, this would cause
warnings to be emitted, as the returned metadata are not valid controls
which can be set.

This is fixed by introducing a new member which only holds the metadata
returned by the requests, so that the controls and the metadata are now
completely independent from each other.

Signed-off-by: Jaslo Ziska <jaslo at ziska.de>
---
 src/gstreamer/gstlibcamera-controls.cpp.in | 22 ++++++++++++++++------
 src/gstreamer/gstlibcamera-controls.h      |  4 +++-
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/gstreamer/gstlibcamera-controls.cpp.in b/src/gstreamer/gstlibcamera-controls.cpp.in
index 89c530da..490e835e 100644
--- a/src/gstreamer/gstlibcamera-controls.cpp.in
+++ b/src/gstreamer/gstlibcamera-controls.cpp.in
@@ -153,20 +153,24 @@ g_param_spec_{{ ctrl.gtype }}(
 bool GstCameraControls::getProperty(guint propId, GValue *value,
 				    [[maybe_unused]] GParamSpec *pspec)
 {
-	if (!controls_acc_.contains(propId)) {
+	const ControlValue *cv;
+	if (controls_acc_.contains(propId)) {
+		cv = &controls_acc_.get(propId);
+	} else if (metadata_.contains(propId)) {
+		cv = &metadata_.get(propId);
+	} else {
 		GST_WARNING("Control '%s' is not available, default value will "
 			    "be returned",
 			    controls::controls.at(propId)->name().c_str());
 		return true;
 	}
-	const ControlValue &cv = controls_acc_.get(propId);
 
 	switch (propId) {
 {%- for vendor, ctrls in controls %}
 {%- for ctrl in ctrls %}
 
 	case controls::{{ ctrl.namespace }}{{ ctrl.name|snake_case|upper }}: {
-		auto control = cv.get<{{ ctrl.type }}>();
+		auto control = cv->get<{{ ctrl.type }}>();
 
 {%- if ctrl.is_array %}
 		for (size_t i = 0; i < control.size(); ++i) {
@@ -309,9 +313,14 @@ void GstCameraControls::setCamera(const std::shared_ptr<libcamera::Camera> &cam)
 				    "camera and will be ignored",
 				    cid->name().c_str());
 	}
-
 	controls_acc_ = new_controls;
 	controls_ = new_controls;
+
+	/*
+	 * Clear metadata as this might already be populated if the element has
+	 * been running before.
+	 */
+	metadata_.clear();
 }
 
 void GstCameraControls::applyControls(std::unique_ptr<libcamera::Request> &request)
@@ -322,6 +331,7 @@ void GstCameraControls::applyControls(std::unique_ptr<libcamera::Request> &reque
 
 void GstCameraControls::readMetadata(libcamera::Request *request)
 {
-	controls_acc_.merge(request->metadata(),
-			    ControlList::MergePolicy::OverwriteExisting);
+	metadata_.merge(request->metadata(),
+			ControlList::MergePolicy::OverwriteExisting);
+
 }
diff --git a/src/gstreamer/gstlibcamera-controls.h b/src/gstreamer/gstlibcamera-controls.h
index 749220b5..ee97e61e 100644
--- a/src/gstreamer/gstlibcamera-controls.h
+++ b/src/gstreamer/gstlibcamera-controls.h
@@ -36,8 +36,10 @@ private:
 	ControlInfoMap capabilities_;
 	/* Set of user modified controls. */
 	ControlList controls_;
-	/* Accumulator of all controls ever set and metadata returned by camera */
+	/* Accumulator of all controls ever */
 	ControlList controls_acc_;
+	/* Metadata returned by requests */
+	ControlList metadata_;
 };
 
 } /* namespace libcamera */
-- 
2.49.0