gecko-dev/layout/generic/nsReflowPath.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** 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) 2002
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Mike Shaver <shaver@mozilla.org>
* Randell Jesup <rjesup@wgate.com>
* Chris Waterson <waterson@netscape.com>
*
* 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 ***** */
#ifndef nsReflowPath_h__
#define nsReflowPath_h__
#include "nscore.h"
#include "pldhash.h"
#include "nsReflowType.h"
#include "nsVoidArray.h"
#ifdef DEBUG
#include <stdio.h>
#endif
class nsIFrame;
class nsHTMLReflowCommand;
class nsPresContext;
/**
* A reflow `path' that is a sparse tree the parallels the frame
* hierarchy. This is used during an incremental reflow to record the
* path which the reflow must trace through the frame hierarchy.
*/
class nsReflowPath
{
public:
/**
* Construct a reflow path object that parallels the specified
* frame.
*/
nsReflowPath(nsIFrame *aFrame)
: mFrame(aFrame),
mReflowCommand(nsnull) {}
~nsReflowPath();
/**
* An iterator for enumerating the reflow path's immediate
* children.
*/
class iterator
{
protected:
nsReflowPath *mNode;
PRInt32 mIndex;
friend class nsReflowPath;
iterator(nsReflowPath *aNode, PRInt32 aIndex)
: mNode(aNode), mIndex(aIndex) {}
void
Advance() { --mIndex; }
public:
iterator()
: mNode(nsnull) {}
iterator(const iterator &iter)
: mNode(iter.mNode), mIndex(iter.mIndex) {}
iterator &
operator=(const iterator &iter) {
mNode = iter.mNode;
mIndex = iter.mIndex;
return *this; }
nsReflowPath *
get() const {
return NS_STATIC_CAST(nsReflowPath *, mNode->mChildren[mIndex]); }
nsReflowPath *
get() {
return NS_STATIC_CAST(nsReflowPath *, mNode->mChildren[mIndex]); }
nsIFrame *
operator*() const {
return get()->mFrame; }
nsIFrame *&
operator*() {
return get()->mFrame; }
iterator &
operator++() { Advance(); return *this; }
iterator
operator++(int) {
iterator temp(*this);
Advance();
return temp; }
PRBool
operator==(const iterator &iter) const {
return (mNode == iter.mNode) && (mIndex == iter.mIndex); }
PRBool
operator!=(const iterator &iter) const {
return !iter.operator==(*this); }
};
/**
* Return an iterator that points to the first immediate child of
* the reflow path.
*/
iterator FirstChild() { return iterator(this, mChildren.Count() - 1); }
/**
* Return an iterator that points `one past the end' of the
* immediate children of the reflow path.
*/
iterator EndChildren() { return iterator(this, -1); }
/**
* Determine if the reflow path contains the specified frame as
* one of its immediate children.
*/
PRBool
HasChild(nsIFrame *aFrame) const {
return GetSubtreeFor(aFrame) != nsnull; }
/**
* Return an iterator over the current reflow path that
* corresponds to the specified child frame. Returns EndChildren
* if aFrame is not an immediate child of the reflow path.
*/
iterator
FindChild(nsIFrame *aFrame);
/**
* Remove the specified child frame from the reflow path, along
* with any of its descendants. Does nothing if aFrame is not an
* immediate child of the reflow path.
*/
void
RemoveChild(nsIFrame *aFrame) {
iterator iter = FindChild(aFrame);
Remove(iter); }
/**
* Return the child reflow path that corresponds to the specified
* frame, or null if the frame is not an immediate descendant.
*/
nsReflowPath *
GetSubtreeFor(nsIFrame *aFrame) const;
/**
* Return the child reflow path that corresponds to the specified
* frame, constructing a new child reflow path if one doesn't
* exist already.
*/
nsReflowPath *
EnsureSubtreeFor(nsIFrame *aFrame);
/**
* Remove the child reflow path that corresponds to the specified
* iterator.
*/
void
Remove(iterator &aIterator);
#ifdef DEBUG
/**
* Recursively dump the reflow path object and its descendants.
*/
void
Dump(nsPresContext *aPresContext, FILE *aFile, int aDepth);
#endif
/**
* The frame that this reflow path object is associated with.
*/
nsIFrame *mFrame;
/**
* If mFrame is the immediate target of an incremental reflow,
* this contains the reflow command that targeted it. Otherwise,
* this is null (and mFrame simply lies along the path to a target
* frame). The reflow path object assumes ownership of the reflow
* command.
*/
nsHTMLReflowCommand *mReflowCommand;
protected:
/**
* The children of this reflow path; also contains pointers to
* nsReflowPath objects.
*/
nsSmallVoidArray mChildren;
friend class iterator;
};
#endif