WebCore/src/kwq/KWQRefPtr.h

/*
 * Copyright (C) 2001 Apple Computer, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#ifndef KWQREFPTR_H_
#define KWQREFPTR_H_

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif


template <class T> class KWQRefPtr {
public:
    explicit KWQRefPtr(T* ptr = 0) : pointer(ptr)
    {
        ref();
    }

    KWQRefPtr(const KWQRefPtr& r) : pointer(r.pointer)
    {
        ref();
    }

    KWQRefPtr& operator=(const KWQRefPtr& r) {
        if (&r != this) {
	    r.ref();
	    unref();
	    pointer = r.pointer;
	}
	return *this;
    }

    ~KWQRefPtr() 
    {
        unref();
    }

    bool isNull() const {
        return pointer == 0;
    }

    T& operator*() const {
        return *pointer;
    }

    T* operator->() const {
        return pointer;
    }

private:
    void unref() 
    {
        if (!isNull()) {
	    if (--pointer->refCount == 0) {
	        delete pointer;
	    }
	}
    }

    void ref() const 
    {
        if (!isNull()) {
  	    ++pointer->refCount;
	}
    }

    T* pointer;
};


#endif