AtomicCow.h

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/*
 * This file is a part of the Biology project by eons LLC.
 * Biology (aka Develop Biology) is a framework for approaching software
 * development from a natural sciences perspective.
 *
 * Copyright (C) 2026 Séon O'Shannon & eons LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "bio/chemical/wrapper/CowPtr.h"
#include "bio/chemical/bonding/Atom.h"
#include "bio/common/wrapper/Pointer.h"
 
namespace bio {
namespace chemical {
 
class AtomicCow :
    public CowPtr< physical::Wave >
{
public:
    AtomicCow(
        Pointer< Atom > source,
        AtomicNumber bondId,
        Pointer< physical::Wave > bondedSnapshot
    )
        :
        CowPtr< physical::Wave >(CowPtr< physical::Wave >::Borrow(bondedSnapshot.Get())),
        mSource(source),
        mBondId(bondId)
    {
    }
 
    bool IsValid() const
    {
        return mSource != NULL;
    }
 
protected:
    const physical::Wave* ReadBonded() const
    {
        return CowPtr< physical::Wave >::View();
    }
 
    Pointer< physical::Wave > WriteBonded()
    {
        if (!mSource)
        {
            return NULL;
        }
        Pointer< physical::Wave > detached = mSource->ResolveBondedForWriteById(mBondId);
        // Refresh our (borrowed, refcount-free) snapshot so a later Read sees the
        // post-detach bonded rather than the now-stale pre-detach one.
        *static_cast< CowPtr< physical::Wave >* >(this) =
            CowPtr< physical::Wave >::Borrow(detached.Get());
        return detached;
    }
 
    Pointer< Atom > mSource;
    AtomicNumber mBondId;
};
 
} // namespace chemical
} // namespace bio