AutoInitializer.h

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#pragma once
 
//
// (C) Copyright 2005-2024 by Graebert GmbH.
//
// Permission to use, copy, modify, and distribute this software in
// object code form for any purpose and without fee is hereby granted,
// provided that the above copyright notice appears in all copies and
// that both that copyright notice and the limited warranty and
// restricted rights notice below appear in all supporting
// documentation.
//
// GRAEBERT PROVIDES THIS PROGRAM "AS IS" AND WITH ALL FAULTS.
// GRAEBERT SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTY OF
// MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE.  GRAEBERT GMBH
// DOES NOT WARRANT THAT THE OPERATION OF THE PROGRAM WILL BE
// UNINTERRUPTED OR ERROR FREE.
 
#include <functional>
 
// This is a workaround for reversing a range-based for loop before c++ 20
namespace ranges
{
    template <typename T>
    struct reversion_wrapper { T& iterable; };
 
    template <typename T>
    auto begin( reversion_wrapper<T> w ) { return std::rbegin( w.iterable ); }
 
    template <typename T>
    auto end( reversion_wrapper<T> w ) { return std::rend( w.iterable ); }
 
    template <typename T>
    reversion_wrapper<T> reverse( T&& iterable ) { return { iterable }; }
};
 
// A static class for automatic initializing/deinitializing custom AcRx classes
class AutoInitializer
{
public:
 
    using FuncType = std::function<void()>;
 
    // This method is used for adding initializers to the list
    static AcRxClass *Add( FuncType const &izer, FuncType const &unizer )
    {
        AutoInitializer::instance()._initializers.push_back( { izer, unizer } );
        return nullptr;
    }
 
private:
 
    AutoInitializer()
    {
    }
 
    ~AutoInitializer()
    {
    }
 
    // Meyers' singleton - ensures that this class will be created before it's use
    static AutoInitializer &instance()
    {
        static AutoInitializer izer;
        return izer;
    }
 
    void _DoInitialize()
    {
        for ( auto &izer : _initializers )
        {
            izer.first();
        }
    }
 
    void _DoUninitialize()
    {
        for ( auto &izer : ranges::reverse( _initializers ) )
        {
            izer.second();
        }
    }
 
    friend class AcRxDbxApp;
 
    // List of initializer and deinitializer functions
    std::vector<std::pair<FuncType, FuncType>> _initializers;
};