treewide: Query list of cameras just once

This is more efficient since only a single vector will be constructed,
and furthermore, it prevents the TOCTOU issue that might arise when
the list of cameras changes between the two queries.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index 6a95b6af..9680d809 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -385,13 +385,14 @@ gst_libcamera_src_open(GstLibcameraSrc *self)
 			return false;
 		}
 	} else {
-		if (cm->cameras().empty()) {
+		auto cameras = cm->cameras();
+		if (cameras.empty()) {
 			GST_ELEMENT_ERROR(self, RESOURCE, NOT_FOUND,
 					  ("Could not find any supported camera on this system."),
 					  ("libcamera::CameraMananger::cameras() is empty"));
 			return false;
 		}
-		cam = cm->cameras()[0];
+		cam = cameras[0];
 	}
 
 	GST_INFO_OBJECT(self, "Using camera '%s'", cam->id().c_str());