File indexing completed on 2024-04-28 15:40:25

 /* SPDX-FileCopyrightText: 2003-2010 Jesper K. Pedersen <blackie@kde.org>
 
    SPDX-License-Identifier: GPL-2.0-or-later
 */
 #include "BooleanGuard.h"
 
 /**
    \class Utilities::BooleanGuard
    \brief Guard that controls entry using a static variable
 
    Sometimes you can get into trouble where a function calls another, which
    indirectly calls the first one again, resulting in an endless
    loop. paintEvent() and resizeEvent() are example of places where this
    sometimes happens.
 
    A solution is to use a static bool as a guard controlling whether the
    function is already in action. This may look like this:
    <pre>
    void f() {
       static bool guard = false;
       if ( guard )
         return;
       guard = true;
       ...
       guard = false;
    }
    </pre>
    This code of course have the problem that the guard is not correctly
    unset, if there is a premature return() in the code. This class solves
    this, and the code will look like this:
 
    <pre>
    void f() {
        static bool inAction = false;
        BooleanGuard guard( inAction );
        if ( !guard.canContinue() )
            return;
 
        ...
    }
    </pre>
 **/
 
 Utilities::BooleanGuard::BooleanGuard(bool &guard)
     : m_guard(guard)
 {
     if (m_guard == false) {
         m_iLockedIt = true;
         m_guard = true;
     } else
         m_iLockedIt = false;
 }
 
 Utilities::BooleanGuard::~BooleanGuard()
 {
     if (m_iLockedIt)
         m_guard = false;
 }
 
 bool Utilities::BooleanGuard::canContinue()
 {
     return m_iLockedIt;
 }
 // vi:expandtab:tabstop=4 shiftwidth=4: