gecko-dev/layout/base/nsFrameContentIterator.cpp

288 строки
7.5 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 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) 2000
* 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 ***** */
#include "nsCOMPtr.h"
#include "nsIContentIterator.h"
#include "nsPresContext.h"
#include "nsIFrame.h"
#include "nsIContent.h"
#include "nsIEnumerator.h"
#include "nsFrameList.h"
class nsFrameContentIterator : public nsIContentIterator
{
public:
nsFrameContentIterator(nsPresContext* aPresContext, nsIFrame* aFrame);
virtual ~nsFrameContentIterator();
// nsISupports
NS_DECL_ISUPPORTS
// nsIContentIterator
virtual nsresult Init(nsIContent* aRoot);
virtual nsresult Init(nsIDOMRange* aRange);
virtual void First();
virtual void Last();
virtual void Next();
virtual void Prev();
virtual nsIContent *GetCurrentNode();
virtual PRBool IsDone();
virtual nsresult PositionAt(nsIContent* aCurNode);
private:
nsCOMPtr<nsPresContext> mPresContext;
nsIFrame* mParentFrame;
nsIFrame* mCurrentChild;
PRBool mIsDone;
};
nsFrameContentIterator::nsFrameContentIterator(nsPresContext* aPresContext,
nsIFrame* aFrame)
: mPresContext(aPresContext), mParentFrame(aFrame), mIsDone(PR_FALSE)
{
First();
}
NS_IMPL_ISUPPORTS1(nsFrameContentIterator, nsIContentIterator)
nsFrameContentIterator::~nsFrameContentIterator()
{
}
nsresult
nsFrameContentIterator::Init(nsIContent* aRoot)
{
return NS_ERROR_ALREADY_INITIALIZED;
}
nsresult
nsFrameContentIterator::Init(nsIDOMRange* aRange)
{
return NS_ERROR_ALREADY_INITIALIZED;
}
void
nsFrameContentIterator::First()
{
// Get the first child frame and make it the current node
mCurrentChild = mParentFrame->GetFirstChild(nsnull);
mIsDone = !mCurrentChild;
}
static nsIFrame*
GetNextChildFrame(nsPresContext* aPresContext, nsIFrame* aFrame)
{
NS_PRECONDITION(aFrame, "null pointer");
// Get the last-in-flow
aFrame = aFrame->GetLastInFlow();
// Get its next sibling
nsIFrame* nextSibling = aFrame->GetNextSibling();
// If there's no next sibling, then check if the parent frame
// has a next-in-flow and look there
if (!nextSibling) {
nsIFrame* parent = aFrame->GetParent()->GetNextInFlow();
if (parent) {
nextSibling = parent->GetFirstChild(nsnull);
}
}
return nextSibling;
}
void
nsFrameContentIterator::Last()
{
// Starting with the first child walk and find the last child
mCurrentChild = nsnull;
nsIFrame* nextChild = mParentFrame->GetFirstChild(nsnull);
while (nextChild) {
mCurrentChild = nextChild;
nextChild = ::GetNextChildFrame(mPresContext, nextChild);
}
mIsDone = !mCurrentChild;
}
void
nsFrameContentIterator::Next()
{
nsIFrame* nextChild = ::GetNextChildFrame(mPresContext, mCurrentChild);
if (nextChild) {
// Advance to the next child
mCurrentChild = nextChild;
// If we're at the end then the collection is at the end
mIsDone = (nsnull == ::GetNextChildFrame(mPresContext, mCurrentChild));
return;
}
// No next frame, we're done.
mIsDone = PR_TRUE;
}
static nsIFrame*
GetPrevChildFrame(nsPresContext* aPresContext, nsIFrame* aFrame)
{
NS_PRECONDITION(aFrame, "null pointer");
// Get its previous sibling. Because we have a singly linked list we
// need to search from the first child
nsIFrame* parent = aFrame->GetParent();
nsIFrame* prevSibling;
nsIFrame* firstChild = parent->GetFirstChild(nsnull);
NS_ASSERTION(firstChild, "parent has no first child");
nsFrameList frameList(firstChild);
prevSibling = frameList.GetPrevSiblingFor(aFrame);
// If there's no previous sibling, then check if the parent frame
// has a prev-in-flow and look there
if (!prevSibling) {
parent = parent->GetPrevInFlow();
if (parent) {
firstChild = parent->GetFirstChild(nsnull);
frameList.SetFrames(firstChild);
prevSibling = frameList.LastChild();
}
}
// Get the first-in-flow
while (PR_TRUE) {
nsIFrame* prevInFlow = prevSibling->GetPrevInFlow();
if (prevInFlow) {
prevSibling = prevInFlow;
} else {
break;
}
}
return prevSibling;
}
void
nsFrameContentIterator::Prev()
{
nsIFrame* prevChild = ::GetPrevChildFrame(mPresContext, mCurrentChild);
if (prevChild) {
// Make the previous child the current child
mCurrentChild = prevChild;
// If we're at the beginning then the collection is at the end
mIsDone = (nsnull == ::GetPrevChildFrame(mPresContext, mCurrentChild));
return;
}
// No previous frame, we're done.
mIsDone = PR_TRUE;
}
nsIContent *
nsFrameContentIterator::GetCurrentNode()
{
if (mCurrentChild && !mIsDone) {
return mCurrentChild->GetContent();
}
return nsnull;
}
PRBool
nsFrameContentIterator::IsDone()
{
return mIsDone;
}
nsresult
nsFrameContentIterator::PositionAt(nsIContent* aCurNode)
{
// Starting with the first child frame search for the child frame
// with the matching content object
nsIFrame* child = mParentFrame->GetFirstChild(nsnull);
while (child) {
if (child->GetContent() == aCurNode) {
break;
}
child = ::GetNextChildFrame(mPresContext, child);
}
if (child) {
// Make it the current child
mCurrentChild = child;
mIsDone = PR_FALSE;
}
return NS_OK;
}
nsresult
NS_NewFrameContentIterator(nsPresContext* aPresContext,
nsIFrame* aFrame,
nsIContentIterator** aIterator)
{
NS_ENSURE_ARG_POINTER(aIterator);
if (!aIterator) {
return NS_ERROR_NULL_POINTER;
}
NS_ENSURE_ARG_POINTER(aFrame);
if (!aFrame) {
return NS_ERROR_NULL_POINTER;
}
// Make sure the frame corresponds to generated content
NS_ASSERTION(aFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT, "unexpected frame");
nsFrameContentIterator* it = new nsFrameContentIterator(aPresContext, aFrame);
if (!it) {
return NS_ERROR_OUT_OF_MEMORY;
}
return it->QueryInterface(NS_GET_IID(nsIContentIterator), (void **)aIterator);
}