utils: add activator helper

The activator should be used to encapsulate activatable objects. It
calls enable on construction and disable on deconstruction. It should
be used for example to enable some opengl settings, while the
activator object is used in local scope. It ensures, that the opengl
setting get disabled, if the scope is left even when throwing an
exception.

2 files changed, 93 insertions, 0 deletions

diff --git a/src/utils/activatable.hpp b/src/utils/activatable.hpp
new file mode 100644
index 00000000..0142ee0d
--- /dev/null
+++ b/src/utils/activatable.hpp
@@ -0,0 +1,38 @@
+/*
+ * UltraStar Deluxe - Karaoke Game
+ *
+ * UltraStar Deluxe is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef ACTIVATABLE_HPP
+#define ACTIVATABLE_HPP
+
+namespace usdx
+{
+    class Activatable
+	{
+	public:
+		virtual void enable(void) = 0;
+		virtual void disable(void) = 0;
+	};
+};
+
+#endif
diff --git a/src/utils/activator.hpp b/src/utils/activator.hpp
new file mode 100644
index 00000000..7384b2a8
--- /dev/null
+++ b/src/utils/activator.hpp
@@ -0,0 +1,55 @@
+/*
+ * UltraStar Deluxe - Karaoke Game
+ *
+ * UltraStar Deluxe is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef ACTIVATOR_HPP
+#define ACTIVATOR_HPP
+
+#include <boost/noncopyable.hpp>
+
+namespace usdx
+{
+	template<typename Activatable>
+    class Activator : public boost::noncopyable
+	{
+	private:
+		Activatable* activatable;
+	public:
+		Activator(Activatable* activatable)
+			: activatable(activatable)
+		{
+			if (activatable) {
+				activatable->enable();
+			}
+		}
+
+		virtual ~Activator()
+		{
+			if (activatable) {
+				activatable->disable();
+			}
+		}
+	};
+};
+
+#endif