Introduce some utilities for C++

red::add_ref will be used to increment a reference counter
and return the object pointer.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>

server/Makefile.am

@@ -96,6 +96,7 @@ libserver_la_SOURCES =				\
 	cursor-channel-client.cpp		\
 	cursor-channel-client.h			\
 	cursor-channel.h			\
+	utils.hpp				\
 	dcc.cpp					\
 	dcc.h					\
 	dcc-private.h				\

server/meson.build

@@ -56,6 +56,7 @@ spice_server_sources = [
   'cursor-channel-client.cpp',
   'cursor-channel-client.h',
   'cursor-channel.h',
+  'utils.hpp',
   'dcc.cpp',
   'dcc.h',
   'dcc-private.h',

server/utils.hpp

@@ -0,0 +1,37 @@
+/*
+   Copyright (C) 2019 Red Hat, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* Generic utilities for C++
+ */
+#pragma once
+
+#include <memory>
+
+namespace red {
+
+
+template <typename T>
+inline T* add_ref(T* p)
+{
+    if (p) {
+        p->ref();
+    }
+    return p;
+}
+
+
+} // namespace red