libcamera: camera: Take span of StreamRole instead of vector

Change the parameter type of `generateConfiguration()` from `const std::vector&`
to `libcamera::Span`. A span is almost always preferable to a const vector ref
because it does not force dynamic allocation when none are needed, and it allows
any contiguous container to be used.

A new overload is added that accepts an initializer list so that

  cam->generateConfiguration({ ... })

keeps working.

There is no API break since a span can be constructed from a vector
and the initializer list overload takes care of the initializer lists,
but this change causes an ABI break.

Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Kieran: Apply checkstyle fixups]
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/camera.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <initializer_list>
 #include <memory>
 #include <set>
 #include <stdint.h>
@@ -105,7 +106,16 @@ public:
 	const ControlList &properties() const;
 
 	const std::set<Stream *> &streams() const;
-	std::unique_ptr<CameraConfiguration> generateConfiguration(const StreamRoles &roles = {});
+
+	std::unique_ptr<CameraConfiguration>
+	generateConfiguration(Span<const StreamRole> roles = {});
+
+	std::unique_ptr<CameraConfiguration>
+	generateConfiguration(std::initializer_list<StreamRole> roles)
+	{
+		return generateConfiguration(Span(roles.begin(), roles.end()));
+	}
+
 	int configure(CameraConfiguration *config);
 
 	std::unique_ptr<Request> createRequest(uint64_t cookie = 0);

include/libcamera/internal/pipeline_handler.h

@@ -49,7 +49,7 @@ public:
 	void release(Camera *camera);
 
 	virtual std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
-		const StreamRoles &roles) = 0;
+									   Span<const StreamRole> roles) = 0;
 	virtual int configure(Camera *camera, CameraConfiguration *config) = 0;
 
 	virtual int exportFrameBuffers(Camera *camera, Stream *stream,