From df20b50cc65361880d49c38d1f023f62daa9ce4b Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Tue, 19 Apr 2022 12:56:10 +0200
Subject: [PATCH] Add ScopeGuard.

---
 src/lib/scope_guard.h    | 51 ++++++++++++++++++++++++++++++++++++++++
 test/scope_guard_test.cc | 36 ++++++++++++++++++++++++++++
 test/wscript             |  1 +
 3 files changed, 88 insertions(+)
 create mode 100644 src/lib/scope_guard.h
 create mode 100644 test/scope_guard_test.cc

diff --git a/src/lib/scope_guard.h b/src/lib/scope_guard.h
new file mode 100644
index 000000000..c26104011
--- /dev/null
+++ b/src/lib/scope_guard.h
@@ -0,0 +1,51 @@
+/*
+    Copyright (C) 2022 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic 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.
+
+    DCP-o-matic 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 DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+
+#include <functional>
+
+
+class ScopeGuard
+{
+public:
+	template <typename F>
+	ScopeGuard (F const& function)
+		: _function(function)
+	{}
+
+	ScopeGuard (ScopeGuard&& other)
+		: _function(std::move(other._function))
+	{
+		other._function = []{};
+	}
+
+	ScopeGuard (ScopeGuard const&) = delete;
+	ScopeGuard& operator=(ScopeGuard const&) = delete;
+
+	~ScopeGuard ()
+	{
+		_function();
+	}
+
+private:
+	std::function<void()> _function;
+};
+
+
diff --git a/test/scope_guard_test.cc b/test/scope_guard_test.cc
new file mode 100644
index 000000000..f984f50db
--- /dev/null
+++ b/test/scope_guard_test.cc
@@ -0,0 +1,36 @@
+/*
+    Copyright (C) 2022 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic 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.
+
+    DCP-o-matic 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 DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+
+#include "lib/scope_guard.h"
+#include <boost/test/unit_test.hpp>
+
+
+BOOST_AUTO_TEST_CASE (scope_guard_test)
+{
+	int x = 0;
+
+	{
+		ScopeGuard sg = [&x]() { x = 42; };
+		BOOST_CHECK_EQUAL (x, 0);
+	}
+
+	BOOST_CHECK_EQUAL (x, 42);
+}
diff --git a/test/wscript b/test/wscript
index 223f70b80..9b1c0173e 100644
--- a/test/wscript
+++ b/test/wscript
@@ -122,6 +122,7 @@ def build(bld):
                  remake_with_subtitle_test.cc
                  render_subtitles_test.cc
                  scaling_test.cc
+                 scope_guard_test.cc
                  silence_padding_test.cc
                  shuffler_test.cc
                  skip_frame_test.cc
-- 
2.30.2