gecko-dev/xpcom/ds/nsConjoiningEnumerator.cpp
warren%netscape.com 9198ea0da6 tweak
1999-03-11 11:01:16 +00:00

393 lines
9.8 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsIEnumerator.h"
////////////////////////////////////////////////////////////////////////////////
// Intersection Enumerators
////////////////////////////////////////////////////////////////////////////////
class nsConjoiningEnumerator : public nsIBidirectionalEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsIEnumerator methods:
NS_IMETHOD First(void);
NS_IMETHOD Next(void);
NS_IMETHOD CurrentItem(nsISupports **aItem);
NS_IMETHOD IsDone(void);
// nsIBidirectionalEnumerator methods:
NS_IMETHOD Last(void);
NS_IMETHOD Prev(void);
// nsConjoiningEnumerator methods:
nsConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second);
virtual ~nsConjoiningEnumerator(void);
protected:
nsIEnumerator* mFirst;
nsIEnumerator* mSecond;
nsIEnumerator* mCurrent;
};
nsConjoiningEnumerator::nsConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second)
: mFirst(first), mSecond(second), mCurrent(first)
{
NS_ADDREF(mFirst);
NS_ADDREF(mSecond);
}
nsConjoiningEnumerator::~nsConjoiningEnumerator(void)
{
NS_RELEASE(mFirst);
NS_RELEASE(mSecond);
}
NS_IMPL_ADDREF(nsConjoiningEnumerator);
NS_IMPL_RELEASE(nsConjoiningEnumerator);
NS_IMETHODIMP
nsConjoiningEnumerator::QueryInterface(REFNSIID aIID, void** aInstancePtr)
{
if (NULL == aInstancePtr)
return NS_ERROR_NULL_POINTER;
if (aIID.Equals(nsIBidirectionalEnumerator::GetIID()) ||
aIID.Equals(nsIEnumerator::GetIID()) ||
aIID.Equals(nsISupports::GetIID())) {
*aInstancePtr = (void*) this;
NS_ADDREF_THIS();
return NS_OK;
}
return NS_NOINTERFACE;
}
NS_IMETHODIMP
nsConjoiningEnumerator::First(void)
{
mCurrent = mFirst;
return mCurrent->First();
}
NS_IMETHODIMP
nsConjoiningEnumerator::Next(void)
{
nsresult rv = mCurrent->Next();
if (NS_FAILED(rv) && mCurrent == mFirst) {
mCurrent = mSecond;
rv = mCurrent->First();
}
return rv;
}
NS_IMETHODIMP
nsConjoiningEnumerator::CurrentItem(nsISupports **aItem)
{
return mCurrent->CurrentItem(aItem);
}
NS_IMETHODIMP
nsConjoiningEnumerator::IsDone(void)
{
return (mCurrent == mFirst && mCurrent->IsDone() == NS_OK)
|| (mCurrent == mSecond && mCurrent->IsDone() == NS_OK)
? NS_OK : NS_COMFALSE;
}
////////////////////////////////////////////////////////////////////////////////
NS_IMETHODIMP
nsConjoiningEnumerator::Last(void)
{
nsresult rv;
nsIBidirectionalEnumerator* be;
rv = mSecond->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
if (NS_FAILED(rv)) return rv;
mCurrent = mSecond;
rv = be->Last();
NS_RELEASE(be);
return rv;
}
NS_IMETHODIMP
nsConjoiningEnumerator::Prev(void)
{
nsresult rv;
nsIBidirectionalEnumerator* be;
rv = mCurrent->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
if (NS_FAILED(rv)) return rv;
rv = be->Prev();
NS_RELEASE(be);
if (NS_FAILED(rv) && mCurrent == mSecond) {
rv = mFirst->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
if (NS_FAILED(rv)) return rv;
mCurrent = mFirst;
rv = be->Last();
NS_RELEASE(be);
}
return rv;
}
////////////////////////////////////////////////////////////////////////////////
extern "C" NS_COM nsresult
NS_NewConjoiningEnumerator(nsIEnumerator* first, nsIEnumerator* second,
nsIBidirectionalEnumerator* *aInstancePtrResult)
{
if (aInstancePtrResult == 0)
return NS_ERROR_NULL_POINTER;
nsConjoiningEnumerator* e = new nsConjoiningEnumerator(first, second);
if (e == 0)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(e);
*aInstancePtrResult = e;
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
static nsresult
nsEnumeratorContains(nsIEnumerator* e, nsISupports* item)
{
nsresult rv;
for (e->First(); e->IsDone() != NS_OK; e->Next()) {
nsISupports* other;
rv = e->CurrentItem(&other);
if (NS_FAILED(rv)) return rv;
if (item == other) {
NS_RELEASE(other);
return NS_OK; // true -- exists in enumerator
}
NS_RELEASE(other);
}
return NS_COMFALSE; // false -- doesn't exist
}
////////////////////////////////////////////////////////////////////////////////
// Intersection Enumerators
////////////////////////////////////////////////////////////////////////////////
class nsIntersectionEnumerator : public nsIEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsIEnumerator methods:
NS_IMETHOD First(void);
NS_IMETHOD Next(void);
NS_IMETHOD CurrentItem(nsISupports **aItem);
NS_IMETHOD IsDone(void);
// nsIntersectionEnumerator methods:
nsIntersectionEnumerator(nsIEnumerator* first, nsIEnumerator* second);
virtual ~nsIntersectionEnumerator(void);
protected:
nsIEnumerator* mFirst;
nsIEnumerator* mSecond;
};
nsIntersectionEnumerator::nsIntersectionEnumerator(nsIEnumerator* first, nsIEnumerator* second)
: mFirst(first), mSecond(second)
{
NS_ADDREF(mFirst);
NS_ADDREF(mSecond);
}
nsIntersectionEnumerator::~nsIntersectionEnumerator(void)
{
NS_RELEASE(mFirst);
NS_RELEASE(mSecond);
}
NS_IMPL_ISUPPORTS(nsIntersectionEnumerator, nsIEnumerator::GetIID());
NS_IMETHODIMP
nsIntersectionEnumerator::First(void)
{
nsresult rv = mFirst->First();
if (NS_FAILED(rv)) return rv;
return Next();
}
NS_IMETHODIMP
nsIntersectionEnumerator::Next(void)
{
nsresult rv;
// find the first item that exists in both
for (; mFirst->IsDone() != NS_OK; mFirst->Next()) {
nsISupports* item;
rv = mFirst->CurrentItem(&item);
if (NS_FAILED(rv)) return rv;
// see if it also exists in mSecond
rv = nsEnumeratorContains(mSecond, item);
if (NS_FAILED(rv)) return rv;
NS_RELEASE(item);
if (rv == NS_OK) {
// found in both, so return leaving it as the current item of mFirst
return NS_OK;
}
}
return NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsIntersectionEnumerator::CurrentItem(nsISupports **aItem)
{
return mFirst->CurrentItem(aItem);
}
NS_IMETHODIMP
nsIntersectionEnumerator::IsDone(void)
{
return mFirst->IsDone();
}
////////////////////////////////////////////////////////////////////////////////
extern "C" NS_COM nsresult
NS_NewIntersectionEnumerator(nsIEnumerator* first, nsIEnumerator* second,
nsIEnumerator* *aInstancePtrResult)
{
if (aInstancePtrResult == 0)
return NS_ERROR_NULL_POINTER;
nsIntersectionEnumerator* e = new nsIntersectionEnumerator(first, second);
if (e == 0)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(e);
*aInstancePtrResult = e;
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
// Union Enumerators
////////////////////////////////////////////////////////////////////////////////
class nsUnionEnumerator : public nsIEnumerator
{
public:
NS_DECL_ISUPPORTS
// nsIEnumerator methods:
NS_IMETHOD First(void);
NS_IMETHOD Next(void);
NS_IMETHOD CurrentItem(nsISupports **aItem);
NS_IMETHOD IsDone(void);
// nsUnionEnumerator methods:
nsUnionEnumerator(nsIEnumerator* first, nsIEnumerator* second);
virtual ~nsUnionEnumerator(void);
protected:
nsIEnumerator* mFirst;
nsIEnumerator* mSecond;
};
nsUnionEnumerator::nsUnionEnumerator(nsIEnumerator* first, nsIEnumerator* second)
: mFirst(first), mSecond(second)
{
NS_ADDREF(mFirst);
NS_ADDREF(mSecond);
}
nsUnionEnumerator::~nsUnionEnumerator(void)
{
NS_RELEASE(mFirst);
NS_RELEASE(mSecond);
}
NS_IMPL_ISUPPORTS(nsUnionEnumerator, nsIEnumerator::GetIID());
NS_IMETHODIMP
nsUnionEnumerator::First(void)
{
nsresult rv = mFirst->First();
if (NS_FAILED(rv)) return rv;
return Next();
}
NS_IMETHODIMP
nsUnionEnumerator::Next(void)
{
nsresult rv;
// find the first item that exists in both
for (; mFirst->IsDone() != NS_OK; mFirst->Next()) {
nsISupports* item;
rv = mFirst->CurrentItem(&item);
if (NS_FAILED(rv)) return rv;
// see if it also exists in mSecond
rv = nsEnumeratorContains(mSecond, item);
if (NS_FAILED(rv)) return rv;
NS_RELEASE(item);
if (rv != NS_OK) {
// if it didn't exist in mSecond, return, making it the current item
return NS_OK;
}
// each time around, make sure that mSecond gets reset to the beginning
// so that when mFirst is done, we'll be ready to enumerate mSecond
rv = mSecond->First();
if (NS_FAILED(rv)) return rv;
}
return mSecond->Next();
}
NS_IMETHODIMP
nsUnionEnumerator::CurrentItem(nsISupports **aItem)
{
if (mFirst->IsDone() != NS_OK)
return mFirst->CurrentItem(aItem);
else
return mSecond->CurrentItem(aItem);
}
NS_IMETHODIMP
nsUnionEnumerator::IsDone(void)
{
return (mFirst->IsDone() == NS_OK && mSecond->IsDone() == NS_OK)
? NS_OK : NS_COMFALSE;
}
////////////////////////////////////////////////////////////////////////////////
extern "C" NS_COM nsresult
NS_NewUnionEnumerator(nsIEnumerator* first, nsIEnumerator* second,
nsIEnumerator* *aInstancePtrResult)
{
if (aInstancePtrResult == 0)
return NS_ERROR_NULL_POINTER;
nsUnionEnumerator* e = new nsUnionEnumerator(first, second);
if (e == 0)
return NS_ERROR_OUT_OF_MEMORY;
NS_ADDREF(e);
*aInstancePtrResult = e;
return NS_OK;
}
////////////////////////////////////////////////////////////////////////////////