mirror of
https://github.com/mozilla/gecko-dev.git
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164 lines
4.6 KiB
C++
164 lines
4.6 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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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 the Mozilla browser.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications, Inc.
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* Portions created by the Initial Developer are Copyright (C) 1999
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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@netscape.com>
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* Pierre Phaneuf <pp@ludusdesign.com>
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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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// nsWeakReference.cpp
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#include "nsWeakReference.h"
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#include "nsCOMPtr.h"
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class nsWeakReference : public nsIWeakReference
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{
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public:
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// nsISupports...
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NS_DECL_ISUPPORTS
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// nsIWeakReference...
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NS_DECL_NSIWEAKREFERENCE
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private:
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friend class nsSupportsWeakReference;
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nsWeakReference( nsSupportsWeakReference* referent )
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: mReferent(referent)
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// ...I can only be constructed by an |nsSupportsWeakReference|
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{
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// nothing else to do here
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}
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~nsWeakReference()
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// ...I will only be destroyed by calling |delete| myself.
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{
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if ( mReferent )
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mReferent->NoticeProxyDestruction();
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}
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void
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NoticeReferentDestruction()
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// ...called (only) by an |nsSupportsWeakReference| from _its_ dtor.
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{
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mReferent = 0;
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}
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nsSupportsWeakReference* mReferent;
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};
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nsresult
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nsQueryReferent::operator()( const nsIID& aIID, void** answer ) const
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{
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nsresult status;
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if ( mWeakPtr )
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{
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if ( NS_FAILED(status = mWeakPtr->QueryReferent(aIID, answer)) )
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*answer = 0;
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}
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else
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status = NS_ERROR_NULL_POINTER;
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if ( mErrorPtr )
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*mErrorPtr = status;
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return status;
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}
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NS_COM_GLUE nsIWeakReference* // or else |already_AddRefed<nsIWeakReference>|
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NS_GetWeakReference( nsISupports* aInstancePtr, nsresult* aErrorPtr )
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{
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nsresult status;
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nsIWeakReference* result = nsnull;
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if ( aInstancePtr )
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{
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nsCOMPtr<nsISupportsWeakReference> factoryPtr = do_QueryInterface(aInstancePtr, &status);
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NS_ASSERTION(factoryPtr, "Oops! You're asking for a weak reference to an object that doesn't support that.");
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if ( factoryPtr )
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{
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status = factoryPtr->GetWeakReference(&result);
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}
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// else, |status| has already been set by |do_QueryInterface|
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}
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else
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status = NS_ERROR_NULL_POINTER;
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if ( aErrorPtr )
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*aErrorPtr = status;
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return result;
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}
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NS_COM_GLUE nsresult
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nsSupportsWeakReference::GetWeakReference( nsIWeakReference** aInstancePtr )
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{
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if ( !aInstancePtr )
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return NS_ERROR_NULL_POINTER;
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if ( !mProxy )
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mProxy = new nsWeakReference(this);
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*aInstancePtr = mProxy;
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nsresult status;
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if ( !*aInstancePtr )
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status = NS_ERROR_OUT_OF_MEMORY;
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else
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{
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NS_ADDREF(*aInstancePtr);
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status = NS_OK;
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}
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return status;
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}
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NS_IMPL_ISUPPORTS1(nsWeakReference, nsIWeakReference)
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NS_IMETHODIMP
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nsWeakReference::QueryReferent( const nsIID& aIID, void** aInstancePtr )
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{
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return mReferent ? mReferent->QueryInterface(aIID, aInstancePtr) : NS_ERROR_NULL_POINTER;
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}
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void
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nsSupportsWeakReference::ClearWeakReferences()
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{
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if ( mProxy )
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{
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mProxy->NoticeReferentDestruction();
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mProxy = 0;
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}
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}
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