libcamera: device_enumerator: Remove move() on search() return

Remove the std::move() call on the shared_ptr<MediaDevice *> returned by
the search() method and remove the std::move() call on temporary return
value in pipeline handlers that use the method.

Thanks to copy elision, the regular constructor of the newly created
object is called, avoiding un-necessary copies.

Furthermore, the use of std::move() in the return and assignment
statements prevents the compiler from performing copy elision, forcing
it to generate two sequences of un-necessary calls to the class'
move constructor and destructor.

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/device_enumerator.cpp

@@ -308,7 +308,7 @@ std::shared_ptr<MediaDevice> DeviceEnumerator::search(const DeviceMatch &dm)
 			LOG(DeviceEnumerator, Debug)
 				<< "Successful match for media device \""
 				<< media->driver() << "\"";
-			return std::move(media);
+			return media;
 		}
 	}
 

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -278,11 +278,11 @@ bool PipelineHandlerIPU3::match(DeviceEnumerator *enumerator)
 	imgu_dm.add("ipu3-imgu 1 viewfinder");
 	imgu_dm.add("ipu3-imgu 1 3a stat");
 
-	cio2_ = std::move(enumerator->search(cio2_dm));
+	cio2_ = enumerator->search(cio2_dm);
 	if (!cio2_)
 		return false;
 
-	imgu_ = std::move(enumerator->search(imgu_dm));
+	imgu_ = enumerator->search(imgu_dm);
 	if (!imgu_)
 		return false;
 

src/libcamera/pipeline/uvcvideo.cpp

@@ -139,7 +139,7 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
 {
 	DeviceMatch dm("uvcvideo");
 
-	media_ = std::move(enumerator->search(dm));
+	media_ = enumerator->search(dm);
 
 	if (!media_)
 		return false;

src/libcamera/pipeline/vimc.cpp

@@ -148,7 +148,7 @@ bool PipelineHandlerVimc::match(DeviceEnumerator *enumerator)
 	dm.add("RGB/YUV Input");
 	dm.add("Scaler");
 
-	media_ = std::move(enumerator->search(dm));
+	media_ = enumerator->search(dm);
 	if (!media_)
 		return false;