JUCE/modules/juce_core/containers/juce_ScopedValueSetter.h

/*
  ==============================================================================

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE 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.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

  ==============================================================================
*/

#ifndef __JUCE_SCOPEDVALUESETTER_JUCEHEADER__
#define __JUCE_SCOPEDVALUESETTER_JUCEHEADER__


//==============================================================================
/**
    Helper class providing an RAII-based mechanism for temporarily setting and
    then re-setting a value.

    E.g. @code
    int x = 1;

    {
        ScopedValueSetter setter (x, 2);

        // x is now 2
    }

    // x is now 1 again

    {
        ScopedValueSetter setter (x, 3, 4);

        // x is now 3
    }

    // x is now 4
    @endcode

*/
template <typename ValueType>
class ScopedValueSetter
{
public:
    /** Creates a ScopedValueSetter that will immediately change the specified value to the
        given new value, and will then reset it to its original value when this object is deleted.
    */
    ScopedValueSetter (ValueType& valueToSet,
                       const ValueType& newValue)
        : value (valueToSet),
          originalValue (valueToSet)
    {
        valueToSet = newValue;
    }

    /** Creates a ScopedValueSetter that will immediately change the specified value to the
        given new value, and will then reset it to be valueWhenDeleted when this object is deleted.
    */
    ScopedValueSetter (ValueType& valueToSet,
                       const ValueType& newValue,
                       const ValueType& valueWhenDeleted)
        : value (valueToSet),
          originalValue (valueWhenDeleted)
    {
        valueToSet = newValue;
    }

    ~ScopedValueSetter()
    {
        value = originalValue;
    }

private:
    //==============================================================================
    ValueType& value;
    const ValueType originalValue;

    JUCE_DECLARE_NON_COPYABLE (ScopedValueSetter);
};


#endif   // __JUCE_SCOPEDVALUESETTER_JUCEHEADER__