146 lines
4.8 KiB
C++
146 lines
4.8 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
|
|
/*
|
|
* This file is part of the LibreOffice project.
|
|
*
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
*
|
|
* This file incorporates work covered by the following license notice:
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed
|
|
* with this work for additional information regarding copyright
|
|
* ownership. The ASF licenses this file to you under the Apache
|
|
* License, Version 2.0 (the "License"); you may not use this file
|
|
* except in compliance with the License. You may obtain a copy of
|
|
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
|
|
*/
|
|
#ifndef INCLUDED_TOOLS_WEAKBASE_H
|
|
#define INCLUDED_TOOLS_WEAKBASE_H
|
|
|
|
#include <sal/types.h>
|
|
#include <osl/diagnose.h>
|
|
|
|
/** the template classes in this header are helper to implement weak references
|
|
to implementation objects that are not refcounted.
|
|
|
|
THIS IS NOT THREADSAFE
|
|
|
|
Use this only to have 'safe' pointers to implementation objects that you
|
|
don't own but that you reference with a pointer.
|
|
|
|
Example:
|
|
|
|
class ImplClass : public tools::WeakBase< ImplClass >
|
|
{
|
|
~ImplClass() { clearWeek(); } // not needed but safer, see method description
|
|
...
|
|
};
|
|
|
|
class UserClass
|
|
{
|
|
tools::WeakReference< ImplClass > mxWeakRef;
|
|
|
|
UserClass( ImplClass* pOjbect ) : mxWeakRef( pObject ) {}
|
|
|
|
DoSomething()
|
|
{
|
|
if( mxWeakRef.is() )
|
|
mxWeakRef->DoSomethingMore();
|
|
}
|
|
};
|
|
*/
|
|
namespace tools
|
|
{
|
|
|
|
/** private connection helper, do not use directly */
|
|
template <class reference_type>
|
|
struct WeakConnection
|
|
{
|
|
sal_Int32 mnRefCount;
|
|
reference_type* mpReference;
|
|
|
|
WeakConnection( reference_type* pReference ) : mnRefCount( 0 ), mpReference( pReference ) {};
|
|
void acquire() { mnRefCount++; }
|
|
void release() { mnRefCount--; if( mnRefCount == 0 ) delete this; }
|
|
};
|
|
|
|
/** template implementation to hold a weak reference to an instance of type reference_type */
|
|
template <class reference_type>
|
|
class WeakReference
|
|
{
|
|
public:
|
|
/** constructs an empty reference */
|
|
inline WeakReference();
|
|
|
|
/** constructs a reference with a pointer to a class derived from WeakBase */
|
|
inline WeakReference( reference_type* pReference );
|
|
|
|
/** constructs a reference with another reference */
|
|
inline WeakReference( const WeakReference< reference_type >& rWeakRef );
|
|
|
|
inline ~WeakReference();
|
|
|
|
/** returns true if the reference object is not null and still alive */
|
|
inline bool is() const;
|
|
|
|
/** returns the pointer to the reference object or null */
|
|
inline reference_type * get() const;
|
|
|
|
/** sets this reference to the given object or null */
|
|
inline void reset( reference_type* pReference );
|
|
|
|
/** returns the pointer to the reference object or null */
|
|
inline reference_type * operator->() const;
|
|
|
|
/** returns true if this instance references pReferenceObject */
|
|
inline bool operator== (const reference_type * pReferenceObject) const;
|
|
|
|
/** returns true if this instance and the given weakref reference the same object */
|
|
inline bool operator== (const WeakReference<reference_type> & handle) const;
|
|
|
|
/** only needed for using this class with stl containers */
|
|
inline bool operator!= (const WeakReference<reference_type> & handle) const;
|
|
|
|
/** only needed for using this class with stl containers */
|
|
inline bool operator< (const WeakReference<reference_type> & handle) const;
|
|
|
|
/** only needed for using this class with stl containers */
|
|
inline bool operator> (const WeakReference<reference_type> & handle) const;
|
|
|
|
/** the assignment operator */
|
|
inline WeakReference<reference_type>& operator= (const WeakReference<reference_type> & handle);
|
|
|
|
private:
|
|
WeakConnection< reference_type >* mpWeakConnection;
|
|
};
|
|
|
|
/** derive your implementation classes from this class if you want them to support weak references */
|
|
template <class reference_type>
|
|
class WeakBase
|
|
{
|
|
friend class WeakReference<reference_type>;
|
|
|
|
public:
|
|
inline WeakBase();
|
|
|
|
inline ~WeakBase();
|
|
/** clears the reference pointer in all living weak references for this instance.
|
|
Further created weak references will also be invalid.
|
|
You should call this method in the d'tor of your derived classes for an early
|
|
invalidate of all living weak references while youre object is already inside
|
|
it d'tor.
|
|
*/
|
|
inline void clearWeak();
|
|
|
|
private:
|
|
inline WeakConnection< reference_type >* getWeakConnection();
|
|
WeakConnection< reference_type >* mpWeakConnection;
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|