gecko/layout/generic/nsSplittableFrame.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2012-05-21 04:12:37 -07:00
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* base class for rendering objects that can be split across lines,
* columns, or pages
*/
#include "nsSplittableFrame.h"
#include "nsIContent.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
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
{
return NS_FRAME_SPLITTABLE;
}
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
bool nsSplittableFrame::IsInPrevContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2)
{
int32_t 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 true;
aFrame1 = aFrame1->GetPrevContinuation();
++iterations;
}
return false;
}
bool nsSplittableFrame::IsInNextContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2)
{
int32_t 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 true;
aFrame1 = aFrame1->GetNextContinuation();
++iterations;
}
return false;
}
#endif
nsIFrame* nsSplittableFrame::GetPrevInFlow() const
{
return (GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION) ? mPrevContinuation : nullptr;
}
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);
return NS_OK;
}
nsIFrame* nsSplittableFrame::GetNextInFlow() const
{
return mNextContinuation && (mNextContinuation->GetStateBits() & NS_FRAME_IS_FLUID_CONTINUATION) ?
mNextContinuation : nullptr;
}
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);
return NS_OK;
}
nsIFrame* nsSplittableFrame::GetFirstInFlow() const
{
nsSplittableFrame* firstInFlow = const_cast<nsSplittableFrame*>(this);
while (nsIFrame *prev = firstInFlow->GetPrevInFlow()) {
firstInFlow = static_cast<nsSplittableFrame*>(prev);
}
NS_POSTCONDITION(firstInFlow, "illegal state in flow chain.");
return firstInFlow;
}
nsIFrame* nsSplittableFrame::GetLastInFlow() const
{
nsSplittableFrame* lastInFlow = const_cast<nsSplittableFrame*>(this);
while (nsIFrame* next = lastInFlow->GetNextInFlow()) {
lastInFlow = static_cast<nsSplittableFrame*>(next);
}
NS_POSTCONDITION(lastInFlow, "illegal state in flow chain.");
return lastInFlow;
}
// Remove this frame from the flow. Connects prev in flow and next in flow
void
nsSplittableFrame::RemoveFromFlow(nsIFrame* aFrame)
{
nsIFrame* prevContinuation = aFrame->GetPrevContinuation();
nsIFrame* nextContinuation = aFrame->GetNextContinuation();
// 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);
}
}
aFrame->SetPrevInFlow(nullptr);
aFrame->SetNextInFlow(nullptr);
}
#ifdef DEBUG
void
nsSplittableFrame::DumpBaseRegressionData(nsPresContext* aPresContext, FILE* out, int32_t aIndent)
{
nsFrame::DumpBaseRegressionData(aPresContext, out, aIndent);
if (nullptr != mNextContinuation) {
IndentBy(out, aIndent);
fprintf(out, "<next-continuation va=\"%p\"/>\n", (void*)mNextContinuation);
}
if (nullptr != mPrevContinuation) {
IndentBy(out, aIndent);
fprintf(out, "<prev-continuation va=\"%p\"/>\n", (void*)mPrevContinuation);
}
}
#endif