pjs/layout/base/nsFrameContentIterator.cpp

293 строки
7.1 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "MPL"); you may not use this file except in
* compliance with the MPL. You may obtain a copy of the MPL at
* http://www.mozilla.org/MPL/
*
* Software distributed under the MPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the MPL
* for the specific language governing rights and limitations under the
* MPL.
*
* The Initial Developer of this code under the MPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 2000 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsCOMPtr.h"
#include "nsIContentIterator.h"
#include "nsIPresContext.h"
#include "nsIFrame.h"
#include "nsIContent.h"
#include "nsIEnumerator.h"
#include "nsFrameList.h"
class nsFrameContentIterator : public nsIContentIterator
{
public:
nsFrameContentIterator(nsIPresContext* aPresContext, nsIFrame* aFrame);
virtual ~nsFrameContentIterator();
// nsISupports
NS_DECL_ISUPPORTS
// nsIContentIterator
NS_IMETHOD Init(nsIContent* aRoot);
NS_IMETHOD Init(nsIDOMRange* aRange);
NS_IMETHOD First();
NS_IMETHOD Last();
NS_IMETHOD Next();
NS_IMETHOD Prev();
NS_IMETHOD CurrentNode(nsIContent **aNode);
NS_IMETHOD IsDone();
NS_IMETHOD PositionAt(nsIContent* aCurNode);
private:
nsCOMPtr<nsIPresContext> mPresContext;
nsIFrame* mParentFrame;
nsIFrame* mCurrentChild;
PRBool mIsDone;
};
nsFrameContentIterator::nsFrameContentIterator(nsIPresContext* aPresContext,
nsIFrame* aFrame)
: mPresContext(aPresContext), mParentFrame(aFrame), mIsDone(PR_FALSE)
{
First();
}
NS_IMPL_ISUPPORTS1(nsFrameContentIterator, nsIContentIterator);
nsFrameContentIterator::~nsFrameContentIterator()
{
}
NS_IMETHODIMP
nsFrameContentIterator::Init(nsIContent* aRoot)
{
return NS_ERROR_ALREADY_INITIALIZED;
}
NS_IMETHODIMP
nsFrameContentIterator::Init(nsIDOMRange* aRange)
{
return NS_ERROR_ALREADY_INITIALIZED;
}
NS_IMETHODIMP
nsFrameContentIterator::First()
{
// Get the first child frame and make it the current node
mParentFrame->FirstChild(mPresContext, nsnull, &mCurrentChild);
if (!mCurrentChild) {
return NS_ERROR_FAILURE;
}
mIsDone = PR_FALSE;
return NS_OK;
}
static nsIFrame*
GetNextChildFrame(nsIPresContext* aPresContext, nsIFrame* aFrame)
{
NS_PRECONDITION(aFrame, "null pointer");
// Get the last-in-flow
aFrame = aFrame->GetLastInFlow();
// Get its next sibling
nsIFrame* nextSibling;
aFrame->GetNextSibling(&nextSibling);
// 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(&parent);
parent->GetNextInFlow(&parent);
if (parent) {
parent->FirstChild(aPresContext, nsnull, &nextSibling);
}
}
return nextSibling;
}
NS_IMETHODIMP
nsFrameContentIterator::Last()
{
nsIFrame* nextChild;
// Starting with the first child walk and find the last child
mCurrentChild = nsnull;
mParentFrame->FirstChild(mPresContext, nsnull, &nextChild);
while (nextChild) {
mCurrentChild = nextChild;
nextChild = ::GetNextChildFrame(mPresContext, nextChild);
}
if (!mCurrentChild) {
return NS_ERROR_FAILURE;
}
mIsDone = PR_FALSE;
return NS_OK;
}
NS_IMETHODIMP
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 NS_OK;
}
return NS_ERROR_FAILURE;
}
static nsIFrame*
GetPrevChildFrame(nsIPresContext* 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;
nsIFrame* firstChild;
nsIFrame* prevSibling;
aFrame->GetParent(&parent);
parent->FirstChild(aPresContext, nsnull, &firstChild);
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->GetPrevInFlow(&parent);
if (parent) {
parent->FirstChild(aPresContext, nsnull, &firstChild);
frameList.SetFrames(firstChild);
prevSibling = frameList.LastChild();
}
}
// Get the first-in-flow
while (PR_TRUE) {
nsIFrame* prevInFlow;
prevSibling->GetPrevInFlow(&prevInFlow);
if (prevInFlow) {
prevSibling = prevInFlow;
} else {
break;
}
}
return prevSibling;
}
NS_IMETHODIMP
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 NS_OK;
}
return NS_ERROR_FAILURE;
}
NS_IMETHODIMP
nsFrameContentIterator::CurrentNode(nsIContent **aNode)
{
if (mCurrentChild) {
mCurrentChild->GetContent(aNode);
return NS_OK;
} else {
*aNode = nsnull;
return NS_ERROR_FAILURE;
}
}
NS_IMETHODIMP
nsFrameContentIterator::IsDone()
{
return mIsDone ? NS_OK : NS_ENUMERATOR_FALSE;
}
NS_IMETHODIMP
nsFrameContentIterator::PositionAt(nsIContent* aCurNode)
{
nsIFrame* child;
// Starting with the first child frame search for the child frame
// with the matching content object
mParentFrame->FirstChild(mPresContext, nsnull, &child);
while (child) {
nsCOMPtr<nsIContent> content;
child->GetContent(getter_AddRefs(content));
if (content.get() == aCurNode) {
break;
}
child = ::GetNextChildFrame(mPresContext, child);
}
if (child) {
// Make it the current child
mCurrentChild = child;
mIsDone = PR_FALSE;
return NS_OK;
}
return NS_ERROR_FAILURE;
}
nsresult
NS_NewFrameContentIterator(nsIPresContext* 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
#ifdef DEBUG
nsFrameState frameState;
aFrame->GetFrameState(&frameState);
NS_ASSERTION(frameState & NS_FRAME_GENERATED_CONTENT, "unexpected frame");
#endif
nsFrameContentIterator* it = new nsFrameContentIterator(aPresContext, aFrame);
if (!it) {
return NS_ERROR_OUT_OF_MEMORY;
}
return it->QueryInterface(NS_GET_IID(nsIContentIterator), (void **)aIterator);
}