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| -rw-r--r-- | src/libs/xpcom18a4/xpcom/glue/nsIWeakReferenceUtils.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/xpcom/glue/nsIWeakReferenceUtils.h b/src/libs/xpcom18a4/xpcom/glue/nsIWeakReferenceUtils.h new file mode 100644 index 00000000..17d1bd79 --- /dev/null +++ b/src/libs/xpcom18a4/xpcom/glue/nsIWeakReferenceUtils.h @@ -0,0 +1,162 @@ +/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* ***** 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 mozilla.org code. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 1998 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Scott Collins <scc@mozilla.org> (Original Author) + * + * 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 nsIWeakReferenceUtils_h__ +#define nsIWeakReferenceUtils_h__ + +#ifndef nsCOMPtr_h__ +#include "nsCOMPtr.h" +#endif + +typedef nsCOMPtr<nsIWeakReference> nsWeakPtr; + +/** + * + */ + +// a type-safe shortcut for calling the |QueryReferent()| member function +// T must inherit from nsIWeakReference, but the cast may be ambiguous. +template <class T, class DestinationType> +inline +nsresult +CallQueryReferent( T* aSource, DestinationType** aDestination ) + { + NS_PRECONDITION(aSource, "null parameter"); + NS_PRECONDITION(aDestination, "null parameter"); + + return aSource->QueryReferent(NS_GET_IID(DestinationType), + NS_REINTERPRET_CAST(void**, aDestination)); + } + + +class NS_COM nsQueryReferent : public nsCOMPtr_helper + { + public: + nsQueryReferent( nsIWeakReference* aWeakPtr, nsresult* error ) + : mWeakPtr(aWeakPtr), + mErrorPtr(error) + { + // nothing else to do here + } + + virtual nsresult NS_FASTCALL operator()( const nsIID& aIID, void** ) const; + + private: + nsIWeakReference* mWeakPtr; + nsresult* mErrorPtr; + }; + +inline +const nsQueryReferent +do_QueryReferent( nsIWeakReference* aRawPtr, nsresult* error = 0 ) + { + return nsQueryReferent(aRawPtr, error); + } + + + +class NS_COM nsGetWeakReference : public nsCOMPtr_helper + { + public: + nsGetWeakReference( nsISupports* aRawPtr, nsresult* error ) + : mRawPtr(aRawPtr), + mErrorPtr(error) + { + // nothing else to do here + } + + virtual nsresult NS_FASTCALL operator()( const nsIID&, void** ) const; + + private: + nsISupports* mRawPtr; + nsresult* mErrorPtr; + }; + + /** + * |do_GetWeakReference| is a convenience function that bundles up all the work needed + * to get a weak reference to an arbitrary object, i.e., the |QueryInterface|, test, and + * call through to |GetWeakReference|, and put it into your |nsCOMPtr|. + * It is specifically designed to cooperate with |nsCOMPtr| (or |nsWeakPtr|) like so: + * |nsWeakPtr myWeakPtr = do_GetWeakReference(aPtr);|. + */ +inline +const nsGetWeakReference +do_GetWeakReference( nsISupports* aRawPtr, nsresult* error = 0 ) + { + return nsGetWeakReference(aRawPtr, error); + } + +inline +void +do_GetWeakReference( nsIWeakReference* aRawPtr, nsresult* error = 0 ) + { + // This signature exists soley to _stop_ you from doing a bad thing. + // Saying |do_GetWeakReference()| on a weak reference itself, + // is very likely to be a programmer error. + } + +template <class T> +inline +void +do_GetWeakReference( already_AddRefed<T>& ) + { + // This signature exists soley to _stop_ you from doing the bad thing. + // Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by + // someone else is an automatic leak. See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>. + } + +template <class T> +inline +void +do_GetWeakReference( already_AddRefed<T>&, nsresult* ) + { + // This signature exists soley to _stop_ you from doing the bad thing. + // Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by + // someone else is an automatic leak. See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>. + } + + + + /** + * Deprecated, use |do_GetWeakReference| instead. + */ +extern NS_COM +nsIWeakReference* +NS_GetWeakReference( nsISupports* , nsresult* aResult=0 ); + +#endif |