/*
 * Copyright 2008, Haiku.
 * Distributed under the terms of the MIT license.
 *
 * Authors:
 *              Michael Pfeiffer <laplace@users.sourceforge.net>
 */

#ifndef _AUTO_DELETE_H
#define _AUTO_DELETE_H

#include <stdlib.h>

/*
Typical usage of this class:

AClass* Klass::Method(int arg) {
        AutoDelete<AClass> variable(new AClass());
        
        if (!IsValid(arg)) {
                ...
                // AutoDelete automatically deletes the AClass object.
                return NULL;
        }
        
        variable.Get()->MethodOfAClass();
        
        // Use Release() to prevent deletion of AClass object.
        return variable.Release();
}
*/

template <class Tp>
class AutoDelete {
private:
        Tp*  fObject;
        bool fOwnsObject; 

        // Deletes the object if it owns it
        void Delete() 
        {
                if (fOwnsObject) {
                        delete fObject; fObject = NULL;
                }
        }

public:

        // Sets the object the class owns       
        AutoDelete(Tp* object = NULL) : fObject(object), fOwnsObject(true) { }
        
        // Deletes the object if it owns it
        virtual ~AutoDelete() 
        {
                Delete();
        }

        // Sets the object the class owns.
        // Deletes a previously owned object and
        // sets the owning flag for the new object.
        void Set(Tp* object) 
        {
                if (fObject == object) return;
                
                Delete();
                fOwnsObject = true;
                fObject = object;
        }
        
        // Returns the object
        Tp* Get() 
        { 
                return fObject; 
        }
        
        // Returns the object and sets owning to false
        // The Get method can still be used to retrieve the object.
        Tp* Release() 
        {
                fOwnsObject = false;
                return fObject;
        }
        
        // Sets the owning flag
        void SetOwnsObject(bool ownsObject) 
        {
                fOwnsObject = ownsObject;
        }
};


#endif