143 lines
4.7 KiB
C++
143 lines
4.7 KiB
C++
/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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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 mozilla.org code.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998
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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@mozilla.org> (Original Author)
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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 nsIWeakReferenceUtils_h__
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#define nsIWeakReferenceUtils_h__
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#ifndef nsCOMPtr_h__
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#include "nsCOMPtr.h"
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#endif
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typedef nsCOMPtr<nsIWeakReference> nsWeakPtr;
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/**
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*
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*/
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// a type-safe shortcut for calling the |QueryReferent()| member function
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// T must inherit from nsIWeakReference, but the cast may be ambiguous.
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template <class T, class DestinationType>
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inline
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nsresult
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CallQueryReferent( T* aSource, DestinationType** aDestination )
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{
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NS_PRECONDITION(aSource, "null parameter");
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NS_PRECONDITION(aDestination, "null parameter");
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return aSource->QueryReferent(NS_GET_IID(DestinationType),
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NS_REINTERPRET_CAST(void**, aDestination));
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}
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class NS_COM_GLUE nsQueryReferent : public nsCOMPtr_helper
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{
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public:
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nsQueryReferent( nsIWeakReference* aWeakPtr, nsresult* error )
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: mWeakPtr(aWeakPtr),
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mErrorPtr(error)
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{
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// nothing else to do here
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}
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virtual nsresult NS_FASTCALL operator()( const nsIID& aIID, void** ) const;
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private:
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nsIWeakReference* mWeakPtr;
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nsresult* mErrorPtr;
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};
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inline
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const nsQueryReferent
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do_QueryReferent( nsIWeakReference* aRawPtr, nsresult* error = 0 )
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{
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return nsQueryReferent(aRawPtr, error);
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}
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/**
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* Deprecated, use |do_GetWeakReference| instead.
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*/
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extern NS_COM_GLUE
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nsIWeakReference*
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NS_GetWeakReference( nsISupports* , nsresult* aResult=0 );
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/**
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* |do_GetWeakReference| is a convenience function that bundles up all the work needed
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* to get a weak reference to an arbitrary object, i.e., the |QueryInterface|, test, and
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* call through to |GetWeakReference|, and put it into your |nsCOMPtr|.
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* It is specifically designed to cooperate with |nsCOMPtr| (or |nsWeakPtr|) like so:
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* |nsWeakPtr myWeakPtr = do_GetWeakReference(aPtr);|.
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*/
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inline
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already_AddRefed<nsIWeakReference>
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do_GetWeakReference( nsISupports* aRawPtr, nsresult* error = 0 )
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{
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return NS_GetWeakReference(aRawPtr, error);
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}
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inline
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void
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do_GetWeakReference( nsIWeakReference* aRawPtr, nsresult* error = 0 )
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{
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// This signature exists soley to _stop_ you from doing a bad thing.
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// Saying |do_GetWeakReference()| on a weak reference itself,
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// is very likely to be a programmer error.
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}
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template <class T>
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inline
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void
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do_GetWeakReference( already_AddRefed<T>& )
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{
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// This signature exists soley to _stop_ you from doing the bad thing.
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// Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by
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// someone else is an automatic leak. See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>.
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}
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template <class T>
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inline
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void
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do_GetWeakReference( already_AddRefed<T>&, nsresult* )
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{
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// This signature exists soley to _stop_ you from doing the bad thing.
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// Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by
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// someone else is an automatic leak. See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>.
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}
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#endif
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