gecko-dev/xpcom/ds/nsSupportsArrayEnumerator.cpp

115 строки
2.4 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsSupportsArrayEnumerator.h"
#include "nsISupportsArray.h"
nsSupportsArrayEnumerator::nsSupportsArrayEnumerator(nsISupportsArray* array)
: mArray(array)
, mCursor(0)
{
NS_ASSERTION(array, "null array");
}
nsSupportsArrayEnumerator::~nsSupportsArrayEnumerator()
{
}
NS_IMPL_ISUPPORTS(nsSupportsArrayEnumerator, nsIBidirectionalEnumerator,
nsIEnumerator)
NS_IMETHODIMP
nsSupportsArrayEnumerator::First()
{
mCursor = 0;
uint32_t cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
int32_t end = (int32_t)cnt;
if (mCursor < end) {
return NS_OK;
} else {
return NS_ERROR_FAILURE;
}
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::Next()
{
uint32_t cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
int32_t end = (int32_t)cnt;
if (mCursor < end) { // don't count upward forever
mCursor++;
}
if (mCursor < end) {
return NS_OK;
} else {
return NS_ERROR_FAILURE;
}
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::CurrentItem(nsISupports** aItem)
{
NS_ASSERTION(aItem, "null out parameter");
uint32_t cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
if (mCursor >= 0 && mCursor < (int32_t)cnt) {
return mArray->GetElementAt(mCursor, aItem);
}
return NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::IsDone()
{
uint32_t cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
// XXX This is completely incompatible with the meaning of nsresult.
// NS_ENUMERATOR_FALSE is defined to be 1. (bug 778111)
return (mCursor >= 0 && mCursor < (int32_t)cnt)
? (nsresult)NS_ENUMERATOR_FALSE : NS_OK;
}
////////////////////////////////////////////////////////////////////////////////
NS_IMETHODIMP
nsSupportsArrayEnumerator::Last()
{
uint32_t cnt;
nsresult rv = mArray->Count(&cnt);
if (NS_FAILED(rv)) {
return rv;
}
mCursor = cnt - 1;
return NS_OK;
}
NS_IMETHODIMP
nsSupportsArrayEnumerator::Prev()
{
if (mCursor >= 0) {
--mCursor;
}
if (mCursor >= 0) {
return NS_OK;
} else {
return NS_ERROR_FAILURE;
}
}