gecko-dev/xpcom/glue/nsWeakReference.cpp

139 lines
3.6 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* 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 the Mozilla browser.
*
* The Initial Developer of the Original Code is Netscape
* Communications, Inc. Portions created by Netscape are
* Copyright (C) 1999, Mozilla. All Rights Reserved.
*
* Contributor(s):
* Scott Collins <scc@netscape.com>
* Pierre Phaneuf <pp@ludusdesign.com>
*/
// nsWeakReference.cpp
#include "nsWeakReference.h"
#include "nsCOMPtr.h"
nsresult
nsQueryReferent::operator()( const nsIID& aIID, void** answer ) const
{
nsresult status;
if ( mWeakPtr )
{
if ( !NS_SUCCEEDED(status = mWeakPtr->QueryReferent(aIID, answer)) )
*answer = 0;
}
else
status = NS_ERROR_NULL_POINTER;
if ( mErrorPtr )
*mErrorPtr = status;
return status;
}
NS_COM nsIWeakReference*
NS_GetWeakReference( nsISupports* aInstancePtr, nsresult* aErrorPtr )
{
nsresult status;
nsIWeakReference* result = 0;
if ( aInstancePtr )
{
nsCOMPtr<nsISupportsWeakReference> factoryPtr = do_QueryInterface(aInstancePtr, &status);
NS_ASSERTION(factoryPtr, "Did you know you were calling |NS_GetWeakReference()| on something that doesn't support weak references?");
if ( factoryPtr )
status = factoryPtr->GetWeakReference(&result);
// else, |status| has already been set by |do_QueryInterface|
}
else
status = NS_ERROR_NULL_POINTER;
if ( aErrorPtr )
*aErrorPtr = status;
return result;
}
NS_IMETHODIMP
nsSupportsWeakReference::GetWeakReference( nsIWeakReference** aInstancePtr )
{
if ( !aInstancePtr )
return NS_ERROR_NULL_POINTER;
if ( !mProxy )
mProxy = new nsWeakReference(this);
*aInstancePtr = mProxy;
nsresult status;
if ( !*aInstancePtr )
status = NS_NOINTERFACE;
else
{
NS_ADDREF(*aInstancePtr);
status = NS_OK;
}
return status;
}
NS_IMETHODIMP_(nsrefcnt)
nsWeakReference::AddRef()
{
return ++mRefCount;
}
NS_IMETHODIMP_(nsrefcnt)
nsWeakReference::Release()
{
nsrefcnt temp = --mRefCount;
if ( !mRefCount )
delete this;
return temp;
}
NS_IMETHODIMP
nsWeakReference::QueryInterface( const nsIID& aIID, void** aInstancePtr )
{
NS_ASSERTION(aInstancePtr, "QueryInterface requires a non-NULL destination!");
if ( !aInstancePtr )
return NS_ERROR_NULL_POINTER;
nsISupports* foundInterface;
if ( aIID.Equals(NS_GET_IID(nsIWeakReference)) )
foundInterface = NS_STATIC_CAST(nsIWeakReference*, this);
else if ( aIID.Equals(NS_GET_IID(nsISupports)) )
foundInterface = NS_STATIC_CAST(nsISupports*, this);
else
foundInterface = 0;
nsresult status;
if ( !foundInterface )
status = NS_NOINTERFACE;
else
{
NS_ADDREF(foundInterface);
status = NS_OK;
}
*aInstancePtr = foundInterface;
return status;
}
NS_IMETHODIMP
nsWeakReference::QueryReferent( const nsIID& aIID, void** aInstancePtr )
{
return mReferent ? mReferent->QueryInterface(aIID, aInstancePtr) : NS_ERROR_NULL_POINTER;
}