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https://github.com/mozilla/gecko-dev.git
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160 lines
4.1 KiB
C++
160 lines
4.1 KiB
C++
/* -*- Mode: C++; 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 Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#include "nsIEnumerator.h"
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class nsConjoiningEnumerator : public nsIBidirectionalEnumerator
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{
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public:
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NS_DECL_ISUPPORTS
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// nsIEnumerator methods:
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NS_IMETHOD First(void);
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NS_IMETHOD Next(void);
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NS_IMETHOD CurrentItem(nsISupports **aItem);
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NS_IMETHOD IsDone(void);
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// nsIBidirectionalEnumerator methods:
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NS_IMETHOD Last(void);
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NS_IMETHOD Prev(void);
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// nsConjoiningEnumerator methods:
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nsConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second);
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virtual ~nsConjoiningEnumerator(void);
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protected:
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nsIEnumerator* mFirst;
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nsIEnumerator* mSecond;
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nsIEnumerator* mCurrent;
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};
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nsConjoiningEnumerator::nsConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second)
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: mFirst(first), mSecond(second), mCurrent(first)
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{
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NS_ADDREF(mFirst);
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NS_ADDREF(mSecond);
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}
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nsConjoiningEnumerator::~nsConjoiningEnumerator(void)
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{
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NS_RELEASE(mFirst);
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NS_RELEASE(mSecond);
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}
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NS_IMPL_ADDREF(nsConjoiningEnumerator);
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NS_IMPL_RELEASE(nsConjoiningEnumerator);
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NS_IMETHODIMP
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nsConjoiningEnumerator::QueryInterface(REFNSIID aIID, void** aInstancePtr)
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{
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if (NULL == aInstancePtr)
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return NS_ERROR_NULL_POINTER;
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if (aIID.Equals(nsIBidirectionalEnumerator::GetIID()) ||
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aIID.Equals(nsIEnumerator::GetIID()) ||
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aIID.Equals(nsISupports::GetIID())) {
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*aInstancePtr = (void*) this;
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NS_ADDREF_THIS();
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return NS_OK;
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}
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return NS_NOINTERFACE;
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}
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NS_IMETHODIMP
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nsConjoiningEnumerator::First(void)
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{
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mCurrent = mFirst;
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return mCurrent->First();
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}
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NS_IMETHODIMP
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nsConjoiningEnumerator:: Next(void)
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{
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nsresult rv = mCurrent->Next();
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if (NS_FAILED(rv) && mCurrent == mFirst) {
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mCurrent = mSecond;
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rv = mCurrent->First();
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}
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return rv;
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}
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NS_IMETHODIMP
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nsConjoiningEnumerator:: CurrentItem(nsISupports **aItem)
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{
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return mCurrent->CurrentItem(aItem);
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}
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NS_IMETHODIMP
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nsConjoiningEnumerator:: IsDone(void)
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{
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return (mCurrent == mFirst && mCurrent->IsDone())
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|| (mCurrent == mSecond && mCurrent->IsDone());
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}
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////////////////////////////////////////////////////////////////////////////////
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NS_IMETHODIMP
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nsConjoiningEnumerator:: Last(void)
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{
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nsresult rv;
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nsIBidirectionalEnumerator* be;
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rv = mSecond->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
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if (NS_FAILED(rv)) return rv;
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mCurrent = mSecond;
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rv = be->Last();
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NS_RELEASE(be);
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return rv;
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}
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NS_IMETHODIMP
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nsConjoiningEnumerator:: Prev(void)
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{
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nsresult rv;
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nsIBidirectionalEnumerator* be;
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rv = mCurrent->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
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if (NS_FAILED(rv)) return rv;
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rv = be->Prev();
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NS_RELEASE(be);
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if (NS_FAILED(rv) && mCurrent == mSecond) {
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rv = mFirst->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
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if (NS_FAILED(rv)) return rv;
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mCurrent = mFirst;
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rv = be->Last();
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NS_RELEASE(be);
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}
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return rv;
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}
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////////////////////////////////////////////////////////////////////////////////
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NS_COM nsresult
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NS_NewConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second,
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nsIBidirectionalEnumerator* *aInstancePtrResult)
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{
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if (aInstancePtrResult == 0)
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return NS_ERROR_NULL_POINTER;
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nsConjoiningEnumerator* e = new nsConjoiningEnumerator(first, second);
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if (e == 0)
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return NS_ERROR_OUT_OF_MEMORY;
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NS_ADDREF(e);
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*aInstancePtrResult = e;
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return NS_OK;
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}
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////////////////////////////////////////////////////////////////////////////////
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