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109 строки
3.7 KiB
Plaintext
109 строки
3.7 KiB
Plaintext
/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Mozilla Public
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* License Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing
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* rights and limitations under the 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 Netscape
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* Communications, Inc. Portions created by Netscape are
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* Copyright (C) 1999, Mozilla. 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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#include "nsISupports.idl"
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/**
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* An instance of |nsIWeakReference| is a proxy object that cooperates with
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* its referent to give clients a non-owning, non-dangling reference. Clients
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* own the proxy, and should generally manage it with an |nsCOMPtr| (see the
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* type |nsWeakPtr| for a |typedef| name that stands out) as they would any
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* other XPCOM object. The |QueryReferent| member function provides a
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* (hopefully short-lived) owning reference on demand, through which clients
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* can get useful access to the referent, while it still exists.
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*
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* @see nsISupportsWeakReference
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* @see nsWeakReference
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* @see nsWeakPtr
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*/
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[scriptable, uuid(9188bc85-f92e-11d2-81ef-0060083a0bcf)]
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interface nsIWeakReference : nsISupports
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{
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/**
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* |QueryReferent| queries the referent, if it exists, and like |QueryInterface|, produces
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* an owning reference to the desired interface. It is designed to look and act exactly
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* like (a proxied) |QueryInterface|. Don't hold on to the produced interface permanently;
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* that would defeat the purpose of using a non-owning |nsIWeakReference| in the first place.
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*/
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void QueryReferent( in nsIIDRef uuid, [iid_is(uuid), retval] out nsQIResult result );
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};
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/**
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* |nsISupportsWeakReference| is a factory interface which produces appropriate
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* instances of |nsIWeakReference|. Weak references in this scheme can only be
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* produced for objects that implement this interface.
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*
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* @see nsIWeakReference
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* @see nsSupportsWeakReference
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*/
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[scriptable, uuid(9188bc86-f92e-11d2-81ef-0060083a0bcf)]
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interface nsISupportsWeakReference : nsISupports
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{
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/**
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* |GetWeakReference| produces an appropriate instance of |nsIWeakReference|.
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* As with all good XPCOM `getters', you own the resulting interface and should
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* manage it with an |nsCOMPtr|.
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*
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* @see nsIWeakReference
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* @see nsWeakPtr
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* @see nsCOMPtr
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*/
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nsIWeakReference GetWeakReference();
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};
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%{C++
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// typedef nsCOMPtr<nsIWeakReference> nsWeakPtr;
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// ...this definition had to be moved to nsWeakPtr.h to avoid circular includes, sorry
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/**
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* |NS_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|. It produces an |nsIWeakReference*| as its
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* function result specifically to cooperate with |nsCOMPtr| (or |nsWeakPtr|) like so:
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* |nsWeakPtr myWeakPtr = getter_AddRefs( NS_GetWeakReference(aPtr) );|.
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*/
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extern NS_COM
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nsIWeakReference*
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NS_GetWeakReference( nsISupports* , nsresult* aResult = 0);
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/**
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*
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*/
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template <class T>
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inline
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nsresult
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CallQueryReferent( nsIWeakReference* aSource, T** 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(nsCOMTypeInfo<T>::GetIID(), (void**)aDestination);
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}
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%}
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