lugre_smartptr.h

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/*
http://www.opensource.org/licenses/mit-license.php  (MIT-License)

Copyright (c) 2007 Lugre-Team

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#ifndef LUGRE_SMARTPTR_H
#define LUGRE_SMARTPTR_H

#include "lugre_prefix.h"
#include <list>
#include <assert.h>


namespace Lugre {

class cListener;
template<class _T> class cSmartPtr;
    
class cListenable { public:
             cListenable();
    virtual ~cListenable();
    void    NotifyAllListeners  (const size_t eventcode = 0,void* param = 0);
    void    RegisterListener    (cListener* pListener,void* userdata = 0);
    void    UnRegisterListener  (cListener* pListener,void* userdata = 0);
    int     CountListeners      () { return mlListener.size(); }
    int         iUsageCounter;
    bool        bNeedsCompacting; 

    private:
    std::list< std::pair< cSmartPtr< cListener > *,void* > >    mlListener;
};

class cISmartPtr { public:
    virtual void    SmartPtr_TargetDestroyed () = 0;
};

template<class _T> class cSmartPtr : public cListenable, public cISmartPtr { public:
    enum { kDefaultTargetDestroyedEventCode = 255 };
    size_t  miTargetDestroyedEventCode;
        
    cSmartPtr(_T* target=0,const size_t iTargetDestroyedEventCode=kDefaultTargetDestroyedEventCode)
                            : miTargetDestroyedEventCode(iTargetDestroyedEventCode), target(target) { PROFILE 
        if (target) target->RegisterSmartPtr(this); 
    }
                            
    virtual ~cSmartPtr()    { PROFILE 
        if (target) target->UnRegisterSmartPtr(this); 
        target = 0; 
    }
    void    SmartPtr_SetTarget (_T* newtarget) { PROFILE
        if (target) target->UnRegisterSmartPtr(this);
        target = newtarget;
        if (target) target->RegisterSmartPtr(this);
    }
    inline const cSmartPtr<_T>& operator = (cSmartPtr<_T> othersmartptr)    { PROFILE SmartPtr_SetTarget(*othersmartptr);   return *this; }
    inline const cSmartPtr<_T>& operator = (_T* newtarget)                  { PROFILE SmartPtr_SetTarget(newtarget);        return *this; }
    inline _T* operator * ()            { return target; }
    
    void    SmartPtr_TargetDestroyed () { PROFILE 
        NotifyAllListeners(miTargetDestroyedEventCode); target = 0;   // anything might happen in here...
    }
    
    private:
    _T* target; 
};

class cSmartPointable : public cListenable { public:

    enum { kDefaultDeathEventCode = 255 };
    size_t  miDeathEventCode;
    
    cSmartPointable(const size_t iDeathEventCode=kDefaultDeathEventCode) : miDeathEventCode(iDeathEventCode) {}
    virtual ~cSmartPointable() { PROFILE 
        ReleaseAllSmartPtr(); 
        NotifyAllListeners(miDeathEventCode);
    }
    void    ReleaseAllSmartPtr  () { PROFILE 
        // foreach mlPtr
        for (std::list<cISmartPtr*>::iterator itor = mlPtr.begin();itor != mlPtr.end();++itor) {
            if (*itor) (*itor)->SmartPtr_TargetDestroyed();  // this causes a notify, anything might happen in here...
        }
        mlPtr.clear();
    }
    void    RegisterSmartPtr    (cISmartPtr* ptr) { PROFILE 
        assert(ptr); 
        mlPtr.push_back(ptr); 
    }
    void    UnRegisterSmartPtr  (cISmartPtr* ptr) { PROFILE 
        assert(ptr); 
        for (std::list<cISmartPtr*>::iterator itor = mlPtr.begin();itor != mlPtr.end();++itor) 
            if (*itor == ptr)
                *itor = 0;
        // warning, do not remove the smartptrs from the list, this would be fatal if it happens during iteration
        // warning, memory leak. smartpointers cannot be savely removed during iteration so they are just set to zero. 
            // but this is not a big leak and far better than broken iterators (=bug-search-headache)
    }
    int     CountSmartPtrs      () { return mlPtr.size(); }
    
    
    private:
    std::list<cISmartPtr*>  mlPtr;
};
    
class cListener : public cSmartPointable { public: // cSmartPointable might also become listenable
    cListener() {}
    virtual ~cListener() {}
    virtual void Listener_Notify (cListenable* pTarget,const size_t eventcode = 0,void* param = 0,void* userdata = 0) = 0;
};

};

#endif