42 lines
1.2 KiB
C++
42 lines
1.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* functions for restoring saved values at the end of a C++ scope */
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#ifndef mozilla_AutoRestore_h_
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#define mozilla_AutoRestore_h_
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#include "mozilla/Attributes.h" // MOZ_STACK_CLASS
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namespace mozilla {
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/**
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* Save the current value of a variable and restore it when the object
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* goes out of scope. For example:
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* {
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* AutoRestore<bool> savePainting(mIsPainting);
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* mIsPainting = true;
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*
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* // ... your code here ...
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*
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* // mIsPainting is reset to its old value at the end of this block
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* }
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*/
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template <class T>
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class MOZ_RAII AutoRestore {
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private:
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T& mLocation;
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T mValue;
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public:
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explicit AutoRestore(T& aValue) : mLocation(aValue), mValue(aValue) {}
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~AutoRestore() { mLocation = mValue; }
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T SavedValue() const { return mValue; }
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};
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} // namespace mozilla
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#endif /* !defined(mozilla_AutoRestore_h_) */
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