DynamicSubscription.h

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/* Copyright (C) 2020 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef INCLUDED_DYNAMICSUBSCRIPTION
#define INCLUDED_DYNAMICSUBSCRIPTION
 
#include "IComponent.h"
 
#include <set>
#include <vector>
 
/**
 * A list of components that are dynamically subscribed to a particular
 * message. The components list is sorted by (entity_id, ComponentTypeId),
 * with no duplicates.
 *
 * To cope with changes to the subscription list while a message is still
 * being broadcast, all changes are stored in the added/removed sets. The
 * next time a message is sent, they will be merged into the main components
 * list.
 */
class CDynamicSubscription
{
    struct CompareIComponent
    {
        bool operator()(const IComponent* cmpA, const IComponent* cmpB) const
        {
            entity_id_t entityA = cmpA->GetEntityId();
            entity_id_t entityB = cmpB->GetEntityId();
            if (entityA < entityB)
                return true;
            if (entityB < entityA)
                return false;
            int cidA = cmpA->GetComponentTypeId();
            int cidB = cmpB->GetComponentTypeId();
            if (cidA < cidB)
                return true;
            return false;
        }
    };
public:
    void Add(IComponent* cmp);
    void Remove(IComponent* cmp);
    void Flatten();
    const std::vector<IComponent*>& GetComponents();
    void DebugDump();
 
private:
    std::vector<IComponent*> m_Components; // always in CompareIComponent order
    std::set<IComponent*, CompareIComponent> m_Added;
    std::set<IComponent*, CompareIComponent> m_Removed;
};
 
#endif // INCLUDED_DYNAMICSUBSCRIPTION