From 1bf1084f2b10c3b47fd1a588d85d21ed0eb41d0c Mon Sep 17 00:00:00 2001 From: Lorry Tar Creator Date: Tue, 27 Jun 2017 06:07:23 +0000 Subject: webkitgtk-2.16.5 --- Source/WTF/wtf/SetForScope.h | 71 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 Source/WTF/wtf/SetForScope.h (limited to 'Source/WTF/wtf/SetForScope.h') diff --git a/Source/WTF/wtf/SetForScope.h b/Source/WTF/wtf/SetForScope.h new file mode 100644 index 000000000..785d9cb34 --- /dev/null +++ b/Source/WTF/wtf/SetForScope.h @@ -0,0 +1,71 @@ +/* + * Copyright (C) 2011 Google Inc. All rights reserved. + * Copyright (C) 2016 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#pragma once + +#include +#include + +namespace WTF { + +// SetForScope<> is useful for setting a variable to a new value only within a +// particular scope. An SetForScope<> object changes a variable to its original +// value upon destruction, making it an alternative to writing "var = false;" +// or "var = oldVal;" at all of a block's exit points. +// +// This should be obvious, but note that an SetForScope<> instance should have a +// shorter lifetime than its scopedVariable, to prevent invalid memory writes +// when the SetForScope<> object is destroyed. + +template +class SetForScope { + WTF_MAKE_NONCOPYABLE(SetForScope); +public: + SetForScope(T& scopedVariable) + : m_scopedVariable(scopedVariable) + , m_originalValue(scopedVariable) + { + } + template + SetForScope(T& scopedVariable, U&& newValue) + : SetForScope(scopedVariable) + { + m_scopedVariable = std::forward(newValue); + } + + ~SetForScope() + { + m_scopedVariable = WTFMove(m_originalValue); + } + +private: + T& m_scopedVariable; + T m_originalValue; +}; + +} + +using WTF::SetForScope; -- cgit v1.2.1