Add ScopeGuard.

4 files changed, 127 insertions, 0 deletions

diff --git a/src/scope_guard.h b/src/scope_guard.h
new file mode 100644
index 00000000..37b963ad
--- /dev/null
+++ b/src/scope_guard.h
@@ -0,0 +1,76 @@
+/*
+    Copyright (C) 2024 Carl Hetherington <cth@carlh.net>
+
+    This file is part of libdcp.
+
+    libdcp 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.
+
+    libdcp 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 libdcp.  If not, see <http://www.gnu.org/licenses/>.
+
+    In addition, as a special exception, the copyright holders give
+    permission to link the code of portions of this program with the
+    OpenSSL library under certain conditions as described in each
+    individual source file, and distribute linked combinations
+    including the two.
+
+    You must obey the GNU General Public License in all respects
+    for all of the code used other than OpenSSL.  If you modify
+    file(s) with this exception, you may extend this exception to your
+    version of the file(s), but you are not obligated to do so.  If you
+    do not wish to do so, delete this exception statement from your
+    version.  If you delete this exception statement from all source
+    files in the program, then also delete it here.
+*/
+
+
+#ifndef LIBDCP_SCOPE_GUARD_H
+#define LIBDCP_SCOPE_GUARD_H
+
+
+#include <functional>
+
+
+namespace dcp {
+
+
+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;
+};
+
+
+}
+
+
+#endif
+
diff --git a/src/wscript b/src/wscript
index 3bc8537b..c2d499c8 100644
--- a/src/wscript
+++ b/src/wscript
@@ -208,6 +208,7 @@ def build(bld):
               ref.h
               ruby.h
               s_gamut3_transfer_function.h
+              scope_guard.h
               search.h
               smpte_load_font_node.h
               smpte_subtitle_asset.h
diff --git a/test/scope_guard_test.cc b/test/scope_guard_test.cc
new file mode 100644
index 00000000..54c0dcbb
--- /dev/null
+++ b/test/scope_guard_test.cc
@@ -0,0 +1,49 @@
+/*
+    Copyright (C) 2015-2021 Carl Hetherington <cth@carlh.net>
+
+    This file is part of libdcp.
+
+    libdcp 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.
+
+    libdcp 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 libdcp.  If not, see <http://www.gnu.org/licenses/>.
+
+    In addition, as a special exception, the copyright holders give
+    permission to link the code of portions of this program with the
+    OpenSSL library under certain conditions as described in each
+    individual source file, and distribute linked combinations
+    including the two.
+
+    You must obey the GNU General Public License in all respects
+    for all of the code used other than OpenSSL.  If you modify
+    file(s) with this exception, you may extend this exception to your
+    version of the file(s), but you are not obligated to do so.  If you
+    do not wish to do so, delete this exception statement from your
+    version.  If you delete this exception statement from all source
+    files in the program, then also delete it here.
+*/
+
+
+#include "scope_guard.h"
+#include <boost/test/unit_test.hpp>
+
+
+BOOST_AUTO_TEST_CASE(scope_guard_test)
+{
+	int x = 0;
+
+	{
+		dcp::ScopeGuard sg = [&x]() { x = 42; };
+		BOOST_CHECK_EQUAL (x, 0);
+	}
+
+	BOOST_CHECK_EQUAL (x, 42);
+}
diff --git a/test/wscript b/test/wscript
index 4d9278eb..d2cac0b3 100644
--- a/test/wscript
+++ b/test/wscript
@@ -104,6 +104,7 @@ def build(bld):
                  recovery_test.cc
                  rgb_xyz_test.cc
                  round_trip_test.cc
+                 scope_guard_test.cc
                  shared_subtitle_test.cc
                  smpte_load_font_test.cc
                  smpte_subtitle_test.cc