libcamera: stream: add initial Stream class

Add an initial Stream implementation. The idea is that once capability
support is added to the library each stream will describe its
capabilities using this class. An application will then select one or
more streams based on these capabilities and use them to configure the
camera and capture.

At this stage the Stream class is empty as capabilities are yet to be
added. The class is still useful as it will be used to communicate how
many streams a Camera object provides.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/libcamera.h

@@ -12,6 +12,7 @@
 #include <libcamera/event_dispatcher.h>
 #include <libcamera/event_notifier.h>
 #include <libcamera/signal.h>
+#include <libcamera/stream.h>
 #include <libcamera/timer.h>
 
 #endif /* __LIBCAMERA_LIBCAMERA_H__ */

include/libcamera/meson.build

@@ -5,6 +5,7 @@ libcamera_api = files([
     'event_notifier.h',
     'libcamera.h',
     'signal.h',
+    'stream.h',
     'timer.h',
 ])
 

include/libcamera/stream.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * stream.h - Video stream for a Camera
+ */
+#ifndef __LIBCAMERA_STREAM_H__
+#define __LIBCAMERA_STREAM_H__
+
+namespace libcamera {
+
+class Stream final
+{
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_STREAM_H__ */