pjs/layout/generic/nsSplittableFrame.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
* 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/
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*
* 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.
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*
* 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 ***** */
/*
* base class for rendering objects that can be split across lines,
* columns, or pages
*/
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#include "nsSplittableFrame.h"
#include "nsIContent.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
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NS_IMPL_FRAMEARENA_HELPERS(nsSplittableFrame)
NS_IMETHODIMP
nsSplittableFrame::Init(nsIContent* aContent,
nsIFrame* aParent,
nsIFrame* aPrevInFlow)
{
nsresult rv = nsFrame::Init(aContent, aParent, aPrevInFlow);
if (aPrevInFlow) {
// Hook the frame into the flow
SetPrevInFlow(aPrevInFlow);
aPrevInFlow->SetNextInFlow(this);
}
return rv;
}
void
nsSplittableFrame::DestroyFrom(nsIFrame* aDestructRoot)
{
// Disconnect from the flow list
if (mPrevContinuation || mNextContinuation) {
RemoveFromFlow(this);
}
// Let the base class destroy the frame
nsFrame::DestroyFrom(aDestructRoot);
}
nsSplittableType
nsSplittableFrame::GetSplittableType() const
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{
return NS_FRAME_SPLITTABLE;
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}
nsIFrame* nsSplittableFrame::GetPrevContinuation() const
{
return mPrevContinuation;
}
NS_METHOD nsSplittableFrame::SetPrevContinuation(nsIFrame* aFrame)
{
NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(), "setting a prev continuation with incorrect type!");
NS_ASSERTION (!IsInPrevContinuationChain(aFrame, this), "creating a loop in continuation chain!");
mPrevContinuation = aFrame;
RemoveStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
return NS_OK;
}
nsIFrame* nsSplittableFrame::GetNextContinuation() const
{
return mNextContinuation;
}
NS_METHOD nsSplittableFrame::SetNextContinuation(nsIFrame* aFrame)
{
NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(), "setting a next continuation with incorrect type!");
NS_ASSERTION (!IsInNextContinuationChain(aFrame, this), "creating a loop in continuation chain!");
mNextContinuation = aFrame;
if (aFrame)
aFrame->RemoveStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
return NS_OK;
}
nsIFrame* nsSplittableFrame::GetFirstContinuation() const
{
nsSplittableFrame* firstContinuation = const_cast<nsSplittableFrame*>(this);
while (firstContinuation->mPrevContinuation) {
firstContinuation = static_cast<nsSplittableFrame*>(firstContinuation->mPrevContinuation);
}
NS_POSTCONDITION(firstContinuation, "illegal state in continuation chain.");
return firstContinuation;
}
nsIFrame* nsSplittableFrame::GetLastContinuation() const
{
nsSplittableFrame* lastContinuation = const_cast<nsSplittableFrame*>(this);
while (lastContinuation->mNextContinuation) {
lastContinuation = static_cast<nsSplittableFrame*>(lastContinuation->mNextContinuation);
}
NS_POSTCONDITION(lastContinuation, "illegal state in continuation chain.");
return lastContinuation;
}
#ifdef DEBUG
PRBool nsSplittableFrame::IsInPrevContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2)
{
PRInt32 iterations = 0;
while (aFrame1 && iterations < 10) {
// Bail out after 10 iterations so we don't bog down debug builds too much
if (aFrame1 == aFrame2)
return PR_TRUE;
aFrame1 = aFrame1->GetPrevContinuation();
++iterations;
}
return PR_FALSE;
}
PRBool nsSplittableFrame::IsInNextContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2)
{
PRInt32 iterations = 0;
while (aFrame1 && iterations < 10) {
// Bail out after 10 iterations so we don't bog down debug builds too much
if (aFrame1 == aFrame2)
return PR_TRUE;
aFrame1 = aFrame1->GetNextContinuation();
++iterations;
}
return PR_FALSE;
}
#endif
nsIFrame* nsSplittableFrame::GetPrevInFlow() const
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{
return (GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION) ? mPrevContinuation : nsnull;
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}
NS_METHOD nsSplittableFrame::SetPrevInFlow(nsIFrame* aFrame)
{
NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(), "setting a prev in flow with incorrect type!");
NS_ASSERTION (!IsInPrevContinuationChain(aFrame, this), "creating a loop in continuation chain!");
mPrevContinuation = aFrame;
AddStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
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return NS_OK;
}
nsIFrame* nsSplittableFrame::GetNextInFlow() const
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{
return mNextContinuation && (mNextContinuation->GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION) ?
mNextContinuation : nsnull;
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}
NS_METHOD nsSplittableFrame::SetNextInFlow(nsIFrame* aFrame)
{
NS_ASSERTION (!aFrame || GetType() == aFrame->GetType(), "setting a next in flow with incorrect type!");
NS_ASSERTION (!IsInNextContinuationChain(aFrame, this), "creating a loop in continuation chain!");
mNextContinuation = aFrame;
if (aFrame)
aFrame->AddStateBits(NS_FRAME_IS_FLUID_CONTINUATION);
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return NS_OK;
}
nsIFrame* nsSplittableFrame::GetFirstInFlow() const
{
nsSplittableFrame* firstInFlow = const_cast<nsSplittableFrame*>(this);
while (nsIFrame *prev = firstInFlow->GetPrevInFlow()) {
firstInFlow = static_cast<nsSplittableFrame*>(prev);
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}
NS_POSTCONDITION(firstInFlow, "illegal state in flow chain.");
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return firstInFlow;
}
nsIFrame* nsSplittableFrame::GetLastInFlow() const
{
nsSplittableFrame* lastInFlow = const_cast<nsSplittableFrame*>(this);
while (nsIFrame* next = lastInFlow->GetNextInFlow()) {
lastInFlow = static_cast<nsSplittableFrame*>(next);
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}
NS_POSTCONDITION(lastInFlow, "illegal state in flow chain.");
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return lastInFlow;
}
// Remove this frame from the flow. Connects prev in flow and next in flow
void
nsSplittableFrame::RemoveFromFlow(nsIFrame* aFrame)
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{
nsIFrame* prevContinuation = aFrame->GetPrevContinuation();
nsIFrame* nextContinuation = aFrame->GetNextContinuation();
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// The new continuation is fluid only if the continuation on both sides
// of the removed frame was fluid
if (aFrame->GetPrevInFlow() && aFrame->GetNextInFlow()) {
if (prevContinuation) {
prevContinuation->SetNextInFlow(nextContinuation);
}
if (nextContinuation) {
nextContinuation->SetPrevInFlow(prevContinuation);
}
} else {
if (prevContinuation) {
prevContinuation->SetNextContinuation(nextContinuation);
}
if (nextContinuation) {
nextContinuation->SetPrevContinuation(prevContinuation);
}
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}
aFrame->SetPrevInFlow(nsnull);
aFrame->SetNextInFlow(nsnull);
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}
#ifdef DEBUG
void
nsSplittableFrame::DumpBaseRegressionData(nsPresContext* aPresContext, FILE* out, PRInt32 aIndent)
{
nsFrame::DumpBaseRegressionData(aPresContext, out, aIndent);
if (nsnull != mNextContinuation) {
IndentBy(out, aIndent);
fprintf(out, "<next-continuation va=\"%ld\"/>\n", PRUptrdiff(mNextContinuation));
}
if (nsnull != mPrevContinuation) {
IndentBy(out, aIndent);
fprintf(out, "<prev-continuation va=\"%ld\"/>\n", PRUptrdiff(mPrevContinuation));
}
}
#endif