1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/nsIWeakReferenceUtils.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,108 @@
1.4 +/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsIWeakReferenceUtils_h__
1.10 +#define nsIWeakReferenceUtils_h__
1.11 +
1.12 +#include "nsCOMPtr.h"
1.13 +#include "nsIWeakReference.h"
1.14 +
1.15 +typedef nsCOMPtr<nsIWeakReference> nsWeakPtr;
1.16 +
1.17 +/**
1.18 + *
1.19 + */
1.20 +
1.21 +// a type-safe shortcut for calling the |QueryReferent()| member function
1.22 +// T must inherit from nsIWeakReference, but the cast may be ambiguous.
1.23 +template <class T, class DestinationType>
1.24 +inline
1.25 +nsresult
1.26 +CallQueryReferent( T* aSource, DestinationType** aDestination )
1.27 + {
1.28 + NS_PRECONDITION(aSource, "null parameter");
1.29 + NS_PRECONDITION(aDestination, "null parameter");
1.30 +
1.31 + return aSource->QueryReferent(NS_GET_TEMPLATE_IID(DestinationType),
1.32 + reinterpret_cast<void**>(aDestination));
1.33 + }
1.34 +
1.35 +
1.36 +class NS_COM_GLUE nsQueryReferent : public nsCOMPtr_helper
1.37 + {
1.38 + public:
1.39 + nsQueryReferent( nsIWeakReference* aWeakPtr, nsresult* error )
1.40 + : mWeakPtr(aWeakPtr),
1.41 + mErrorPtr(error)
1.42 + {
1.43 + // nothing else to do here
1.44 + }
1.45 +
1.46 + virtual nsresult NS_FASTCALL operator()( const nsIID& aIID, void** ) const;
1.47 +
1.48 + private:
1.49 + nsIWeakReference* mWeakPtr;
1.50 + nsresult* mErrorPtr;
1.51 + };
1.52 +
1.53 +inline
1.54 +const nsQueryReferent
1.55 +do_QueryReferent( nsIWeakReference* aRawPtr, nsresult* error = 0 )
1.56 + {
1.57 + return nsQueryReferent(aRawPtr, error);
1.58 + }
1.59 +
1.60 +
1.61 + /**
1.62 + * Deprecated, use |do_GetWeakReference| instead.
1.63 + */
1.64 +extern NS_COM_GLUE
1.65 +nsIWeakReference*
1.66 +NS_GetWeakReference( nsISupports* , nsresult* aResult=0 );
1.67 +
1.68 + /**
1.69 + * |do_GetWeakReference| is a convenience function that bundles up all the work needed
1.70 + * to get a weak reference to an arbitrary object, i.e., the |QueryInterface|, test, and
1.71 + * call through to |GetWeakReference|, and put it into your |nsCOMPtr|.
1.72 + * It is specifically designed to cooperate with |nsCOMPtr| (or |nsWeakPtr|) like so:
1.73 + * |nsWeakPtr myWeakPtr = do_GetWeakReference(aPtr);|.
1.74 + */
1.75 +inline
1.76 +already_AddRefed<nsIWeakReference>
1.77 +do_GetWeakReference( nsISupports* aRawPtr, nsresult* error = 0 )
1.78 + {
1.79 + return dont_AddRef(NS_GetWeakReference(aRawPtr, error));
1.80 + }
1.81 +
1.82 +inline
1.83 +void
1.84 +do_GetWeakReference( nsIWeakReference* aRawPtr, nsresult* error = 0 )
1.85 + {
1.86 + // This signature exists solely to _stop_ you from doing a bad thing.
1.87 + // Saying |do_GetWeakReference()| on a weak reference itself,
1.88 + // is very likely to be a programmer error.
1.89 + }
1.90 +
1.91 +template <class T>
1.92 +inline
1.93 +void
1.94 +do_GetWeakReference( already_AddRefed<T>& )
1.95 + {
1.96 + // This signature exists solely to _stop_ you from doing the bad thing.
1.97 + // Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by
1.98 + // someone else is an automatic leak. See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>.
1.99 + }
1.100 +
1.101 +template <class T>
1.102 +inline
1.103 +void
1.104 +do_GetWeakReference( already_AddRefed<T>&, nsresult* )
1.105 + {
1.106 + // This signature exists solely to _stop_ you from doing the bad thing.
1.107 + // Saying |do_GetWeakReference()| on a pointer that is not otherwise owned by
1.108 + // someone else is an automatic leak. See <http://bugzilla.mozilla.org/show_bug.cgi?id=8221>.
1.109 + }
1.110 +
1.111 +#endif
