Unsubscribable.h

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// Copyright (c) 2025 Dave R. Smith.
// Malena Framework — Licensed under PolyForm Noncommercial 1.0.0; commercial use requires a paid license. See LICENSE.
 
//
// Unsubscribable.h
//
 
#ifndef MALENA_UNSUBSCRIBABLE_H
#define MALENA_UNSUBSCRIBABLE_H
 
#pragma once
 
 
#include <Malena/Core/malena_export.h>
#include <Malena/Utilities/EnumKey.h>
namespace ml
{
    class Core;   // fwd: Unsubscribable stores the Core identity (see _selfCore)
    class MALENA_API Unsubscribable
    {
    public:
        template<typename EnumType>
        void unsubscribe(EnumType event)
        {
            static_assert(std::is_enum_v<EnumType>,
                "[Malena] unsubscribe — argument must be an enum value.");
            doUnsubscribe(EnumKey::get(event));
        }
 

        void unsubscribeAll();
 
        virtual ~Unsubscribable() = default;
    private:
        void doUnsubscribe(const std::string& key);
 
        // Core's own identity, stamped by Core's constructor.
        //
        // Why not just dynamic_cast<Core*>(this) at the point of use: widgets
        // call unsubscribeAll() from INSIDE their own constructor (ml::Panel
        // does, and several app scenes do) to drop the empty click/hover
        // subscriptions ComponentCore auto-registers. At that moment the object
        // is still under construction, so RTTI on it is undefined — Clang
        // tolerates it, MSVC hard-fails the process (0xC0000409). Core sets this
        // pointer before any derived constructor runs, so it is always valid by
        // then and needs no RTTI at all.
        Core* _selfCore = nullptr;
        friend class Core;
    };
 
} // namespace ml
 
#endif // MALENA_UNSUBSCRIBABLE_H