nsWeakReference.h
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- /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- *
- * ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (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.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is the Mozilla browser.
- *
- * The Initial Developer of the Original Code is
- * Netscape Communications, Inc.
- * Portions created by the Initial Developer are Copyright (C) 1999
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- * Scott Collins <scc@netscape.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- #ifndef nsWeakReference_h__
- #define nsWeakReference_h__
- // nsWeakReference.h
- #include "nsIWeakReference.h"
- #include "nsIWeakReferenceUtils.h"
- class nsWeakReference;
- #undef IMETHOD_VISIBILITY
- #define IMETHOD_VISIBILITY NS_VISIBILITY_DEFAULT
- class NS_COM_GLUE nsSupportsWeakReference : public nsISupportsWeakReference
- {
- public:
- nsSupportsWeakReference()
- : mProxy(0)
- {
- // nothing else to do here
- }
- NS_DECL_NSISUPPORTSWEAKREFERENCE
- protected:
- inline ~nsSupportsWeakReference();
- private:
- friend class nsWeakReference;
- void
- NoticeProxyDestruction()
- // ...called (only) by an |nsWeakReference| from _its_ dtor.
- {
- mProxy = 0;
- }
- nsWeakReference* mProxy;
- protected:
- inline void ClearWeakReferences();
- PRBool HasWeakReferences() const {return mProxy != 0;}
- };
- #undef IMETHOD_VISIBILITY
- #define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN
- class NS_COM_GLUE nsWeakReference : public nsIWeakReference
- {
- public:
- // nsISupports...
- NS_DECL_ISUPPORTS
- // nsIWeakReference...
- NS_DECL_NSIWEAKREFERENCE
- private:
- friend class nsSupportsWeakReference;
- nsWeakReference( nsSupportsWeakReference* referent )
- : mReferent(referent)
- // ...I can only be constructed by an |nsSupportsWeakReference|
- {
- // nothing else to do here
- }
- ~nsWeakReference()
- // ...I will only be destroyed by calling |delete| myself.
- {
- if ( mReferent )
- mReferent->NoticeProxyDestruction();
- }
- void
- NoticeReferentDestruction()
- // ...called (only) by an |nsSupportsWeakReference| from _its_ dtor.
- {
- mReferent = 0;
- }
- nsSupportsWeakReference* mReferent;
- };
- inline
- void
- nsSupportsWeakReference::ClearWeakReferences()
- /*
- Usually being called from |nsSupportsWeakReference::~nsSupportsWeakReference|
- will be good enough, but you may have a case where you need to call disconnect
- your weak references in an outer destructor (to prevent some client holding a
- weak reference from re-entering your destructor).
- */
- {
- if ( mProxy )
- {
- mProxy->NoticeReferentDestruction();
- mProxy = 0;
- }
- }
- inline
- nsSupportsWeakReference::~nsSupportsWeakReference()
- {
- ClearWeakReferences();
- }
- #endif