gecko/layout/base/nsChildIterator.h

156 lines
4.5 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:cindent:ts=2:et:sw=2:
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* 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 mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* used by nsCSSFrameConstructor to determine and iterate the child list
* used to construct frames (normal children or something from XBL)
*/
#include "nsCOMPtr.h"
#include "nsIContent.h"
#include "nsIDOMNodeList.h"
#include "nsIDOMNode.h"
/**
* Helper class for iterating children during frame construction.
* This class should always be used in lieu of the straight content
* node APIs, since it handles XBL-generated anonymous content as
* well.
*/
class ChildIterator
{
protected:
nsCOMPtr<nsIContent> mContent;
PRUint32 mIndex;
nsCOMPtr<nsIDOMNodeList> mNodes;
public:
ChildIterator()
: mIndex(0) {}
ChildIterator(const ChildIterator& aOther)
: mContent(aOther.mContent),
mIndex(aOther.mIndex),
mNodes(aOther.mNodes) {}
ChildIterator& operator=(const ChildIterator& aOther) {
mContent = aOther.mContent;
mIndex = aOther.mIndex;
mNodes = aOther.mNodes;
return *this;
}
ChildIterator& operator++() {
++mIndex;
return *this;
}
ChildIterator operator++(int) {
ChildIterator result(*this);
++mIndex;
return result;
}
ChildIterator& operator--() {
--mIndex;
return *this;
}
ChildIterator operator--(int) {
ChildIterator result(*this);
--mIndex;
return result;
}
already_AddRefed<nsIContent> get() const {
nsIContent* result = nsnull;
if (mNodes) {
nsCOMPtr<nsIDOMNode> node;
mNodes->Item(mIndex, getter_AddRefs(node));
CallQueryInterface(node, &result);
} else {
result = mContent->GetChildAt(PRInt32(mIndex));
NS_IF_ADDREF(result);
}
return result;
}
already_AddRefed<nsIContent> operator*() const { return get(); }
PRBool operator==(const ChildIterator& aOther) const {
return mContent == aOther.mContent && mIndex == aOther.mIndex;
}
PRBool operator!=(const ChildIterator& aOther) const {
return !aOther.operator==(*this);
}
PRUint32 index() {
return mIndex;
}
void seek(PRUint32 aIndex) {
// Make sure that aIndex is reasonable. This should be |#ifdef
// DEBUG|, but we need these numbers for the temporary workaround
// for bug 133219.
PRUint32 length;
if (mNodes)
mNodes->GetLength(&length);
else
length = mContent->GetChildCount();
NS_ASSERTION(PRInt32(aIndex) >= 0 && aIndex <= length, "out of bounds");
// Temporary workaround for bug 133219.
if (aIndex > length)
aIndex = length;
mIndex = aIndex;
}
/**
* Create a pair of ChildIterators for a content node. aFirst will
* point to the first child of aContent; aLast will point one past
* the last child of aContent.
*/
static nsresult Init(nsIContent* aContent,
ChildIterator* aFirst,
ChildIterator* aLast);
};