YesNoNone.h

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/*
 * Copyright (C) 1996-2019 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

#ifndef SQUID_YESNONONE_H_
#define SQUID_YESNONONE_H_

#include "base/TextException.h"
#include "Debug.h"

// TODO: generalize / template to non-boolean option types
// and make YesNoNone the boolean instance of the template

class YesNoNone
{
    enum SetHow : uint8_t { optUnspecified = 0, optImplicitly = 1, optConfigured = 2 };

public:
    // this constructor initializes to 'unspecified' state
    YesNoNone():
        setHow_(optUnspecified),
        option(false)
    {}

    // this constructor initializes to 'implicit' state
    explicit YesNoNone(bool beSet):
        setHow_(optImplicitly),
        option(beSet)
    {}

    explicit operator bool() const {
        Must(setHow_ != optUnspecified);
        return option;
    }

    void configure(bool beSet) {
        setHow_ = optConfigured;
        option = beSet;
    }

    void defaultTo(bool beSet) {
        Must(setHow_ != optConfigured);
        setHow_ = optImplicitly;
        option = beSet;
    }

    bool configured() const {return setHow_ == optConfigured;}

private:
    SetHow setHow_; 
    bool option; 
};

#endif /* SQUID_YESNONONE_H_ */