gecko-dev/layout/generic/nsSplittableFrame.cpp

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#include "nsSplittableFrame.h"
#include "nsIContent.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"

NS_IMETHODIMP
nsSplittableFrame::Init(nsPresContext*  aPresContext,
                        nsIContent*      aContent,
                        nsIFrame*        aParent,
                        nsStyleContext*  aContext,
                        nsIFrame*        aPrevInFlow)
{
  nsresult  rv;
  
  rv = nsFrame::Init(aPresContext, aContent, aParent, aContext, aPrevInFlow);

  if (aPrevInFlow) {
    // Hook the frame into the flow
    mPrevInFlow = aPrevInFlow;
    aPrevInFlow->SetNextInFlow(this);
  }

  return rv;
}

NS_IMETHODIMP
nsSplittableFrame::Destroy(nsPresContext* aPresContext)
{
  // Disconnect from the flow list
  if (mPrevInFlow || mNextInFlow) {
    RemoveFromFlow(this);
  }

  // Let the base class destroy the frame
  return nsFrame::Destroy(aPresContext);
}

NS_IMETHODIMP
nsSplittableFrame::IsSplittable(nsSplittableType& aIsSplittable) const
{
  aIsSplittable = NS_FRAME_SPLITTABLE;
  return NS_OK;
}

nsIFrame* nsSplittableFrame::GetPrevInFlow() const
{
  return mPrevInFlow;
}

NS_METHOD nsSplittableFrame::SetPrevInFlow(nsIFrame* aFrame)
{
  mPrevInFlow = aFrame;
  return NS_OK;
}

nsIFrame* nsSplittableFrame::GetNextInFlow() const
{
  return mNextInFlow;
}

NS_METHOD nsSplittableFrame::SetNextInFlow(nsIFrame* aFrame)
{
  mNextInFlow = aFrame;
  return NS_OK;
}

nsIFrame* nsSplittableFrame::GetFirstInFlow() const
{
  nsSplittableFrame* firstInFlow = (nsSplittableFrame*)this;
  while (firstInFlow->mPrevInFlow)  {
    firstInFlow = (nsSplittableFrame*)firstInFlow->mPrevInFlow;
  }
  NS_POSTCONDITION(firstInFlow, "illegal state in flow chain.");
  return firstInFlow;
}

nsIFrame* nsSplittableFrame::GetLastInFlow() const
{
  nsSplittableFrame* lastInFlow = (nsSplittableFrame*)this;
  while (lastInFlow->mNextInFlow)  {
    lastInFlow = (nsSplittableFrame*)lastInFlow->mNextInFlow;
  }
  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* prevInFlow = aFrame->GetPrevInFlow();
  nsIFrame* nextInFlow = aFrame->GetNextInFlow();

  if (prevInFlow) {
    prevInFlow->SetNextInFlow(nextInFlow);
  }

  if (nextInFlow) {
    nextInFlow->SetPrevInFlow(prevInFlow);
  }

  aFrame->SetPrevInFlow(nsnull);
  aFrame->SetNextInFlow(nsnull);
}

// Detach from previous frame in flow
void
nsSplittableFrame::BreakFromPrevFlow(nsIFrame* aFrame)
{
  nsIFrame* prevInFlow = aFrame->GetPrevInFlow();
  if (prevInFlow) {
    prevInFlow->SetNextInFlow(nsnull);
    aFrame->SetPrevInFlow(nsnull);
  }
}

#ifdef DEBUG
void
nsSplittableFrame::DumpBaseRegressionData(nsPresContext* aPresContext, FILE* out, PRInt32 aIndent, PRBool aIncludeStyleData)
{
  nsFrame::DumpBaseRegressionData(aPresContext, out, aIndent, aIncludeStyleData);
  if (nsnull != mNextInFlow) {
    IndentBy(out, aIndent);
    fprintf(out, "<next-in-flow va=\"%ld\"/>\n", PRUptrdiff(mNextInFlow));
  }
  if (nsnull != mPrevInFlow) {
    IndentBy(out, aIndent);
    fprintf(out, "<prev-in-flow va=\"%ld\"/>\n", PRUptrdiff(mPrevInFlow));
  }

}
#endif