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