49 lines
1.4 KiB
C++
49 lines
1.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef __nsInterfaceRequestorUtils_h
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#define __nsInterfaceRequestorUtils_h
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#include "nsCOMPtr.h"
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// a type-safe shortcut for calling the |GetInterface()| member function
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// T must inherit from nsIInterfaceRequestor, but the cast may be ambiguous.
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template<class T, class DestinationType>
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inline nsresult
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CallGetInterface(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->GetInterface(NS_GET_TEMPLATE_IID(DestinationType),
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reinterpret_cast<void**>(aDestination));
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}
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class MOZ_STACK_CLASS nsGetInterface final : public nsCOMPtr_helper
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{
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public:
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nsGetInterface(nsISupports* aSource, nsresult* aError)
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: mSource(aSource)
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, mErrorPtr(aError)
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{
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}
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virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const
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override;
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private:
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nsISupports* MOZ_NON_OWNING_REF mSource;
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nsresult* mErrorPtr;
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};
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inline const nsGetInterface
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do_GetInterface(nsISupports* aSource, nsresult* aError = 0)
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{
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return nsGetInterface(aSource, aError);
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}
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#endif // __nsInterfaceRequestorUtils_h
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