libcamera: controls: Use std::optional to handle invalid control values

Previously, ControlList::get<T>() would use default constructed objects to
indicate that a ControlList does not have the requested Control. This has
several disadvantages: 1) It requires types to be default constructible,
2) it does not differentiate between a default constructed object and an
object that happens to have the same state as a default constructed object.

std::optional<T> additionally stores the information if the object is valid
or not, and therefore is more expressive than a default constructed object.

Signed-off-by: Christian Rauch <Rauch.Christian@gmx.de>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/cam/main.cpp b/src/cam/main.cpp
index 79875ed7..d8115cd8 100644
--- a/src/cam/main.cpp
+++ b/src/cam/main.cpp
@@ -301,7 +301,7 @@ std::string CamApp::cameraName(const Camera *camera)
 	 * is only used if the location isn't present or is set to External.
 	 */
 	if (props.contains(properties::Location)) {
-		switch (props.get(properties::Location)) {
+		switch (*props.get(properties::Location)) {
 		case properties::CameraLocationFront:
 			addModel = false;
 			name = "Internal front camera ";
@@ -321,7 +321,7 @@ std::string CamApp::cameraName(const Camera *camera)
 		 * If the camera location is not availble use the camera model
 		 * to build the camera name.
 		 */
-		name = "'" + props.get(properties::Model) + "' ";
+		name = "'" + *props.get(properties::Model) + "' ";
 	}
 
 	name += "(" + camera->id() + ")";