/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 *
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */
#include "nsCOMPtr.h"
#include "nsTableRowGroupFrame.h"
#include "nsTableRowFrame.h"
#include "nsTableFrame.h"
#include "nsTableCellFrame.h"
#include "nsIRenderingContext.h"
#include "nsIPresContext.h"
#include "nsIStyleContext.h"
#include "nsStyleConsts.h"
#include "nsIContent.h"
#include "nsIView.h"
#include "nsIPtr.h"
#include "nsIReflowCommand.h"
#include "nsHTMLIIDs.h"
#include "nsIDeviceContext.h"
#include "nsHTMLAtoms.h"
#include "nsIStyleSet.h"
#include "nsIPresShell.h"
#include "nsLayoutAtoms.h"
#include "nsCSSRendering.h"
#include "nsHTMLParts.h"

NS_DEF_PTR(nsIStyleContext);
NS_DEF_PTR(nsIContent);

/* ----------- nsTableRowGroupFrame ---------- */

nsresult
nsTableRowGroupFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
{
  if (NULL == aInstancePtr) {
    return NS_ERROR_NULL_POINTER;
  }
  static NS_DEFINE_IID(kITableRowGroupIID, NS_ITABLEROWGROUPFRAME_IID);
  if (aIID.Equals(kITableRowGroupIID)) {
    *aInstancePtr = (void*)this;
    return NS_OK;
  } else {
    return nsHTMLContainerFrame::QueryInterface(aIID, aInstancePtr);
  }
}

NS_METHOD nsTableRowGroupFrame::GetRowCount(PRInt32 &aCount, PRBool aDeepCount)
{
  // init out-param
  aCount=0;

  // loop through children, adding one to aCount for every legit row
  nsIFrame *childFrame = GetFirstFrame();
  while (PR_TRUE)
  {
    if (nsnull==childFrame)
      break;
    const nsStyleDisplay *childDisplay;
    childFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
      aCount++;
    else if (aDeepCount && NS_STYLE_DISPLAY_TABLE_ROW_GROUP == childDisplay->mDisplay) {
      PRInt32 childRowGroupCount;
      ((nsTableRowGroupFrame*)childFrame)->GetRowCount(childRowGroupCount);
      aCount += childRowGroupCount;
    }
    GetNextFrame(childFrame, &childFrame);
  }
  return NS_OK;
}

PRInt32 nsTableRowGroupFrame::GetStartRowIndex()
{
  PRInt32 result = -1;
  nsIFrame *childFrame = GetFirstFrame();
  while (PR_TRUE)
  {
    if (nsnull==childFrame)
      break;
    const nsStyleDisplay *childDisplay;
    childFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
    {
      result = ((nsTableRowFrame *)childFrame)->GetRowIndex();
      break;
    }
    else if (NS_STYLE_DISPLAY_TABLE_ROW_GROUP == childDisplay->mDisplay) {
      result = ((nsTableRowGroupFrame*)childFrame)->GetStartRowIndex();
      if (result != -1)
        break;
    }
    
    GetNextFrame(childFrame, &childFrame);
  }
  return result;
}

NS_METHOD nsTableRowGroupFrame::GetMaxColumns(PRInt32 &aMaxColumns)
{
  aMaxColumns=0;
  // loop through children, remembering the max of the columns in each row
  nsIFrame *childFrame = GetFirstFrame();
  while (PR_TRUE)
  {
    if (nsnull==childFrame)
      break;
    const nsStyleDisplay *childDisplay;
    childFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
    {
      PRInt32 colCount = ((nsTableRowFrame *)childFrame)->GetMaxColumns();
      aMaxColumns = PR_MAX(aMaxColumns, colCount);
    }
    else if (NS_STYLE_DISPLAY_TABLE_ROW_GROUP == childDisplay->mDisplay) {
      PRInt32 rgColCount;
      ((nsTableRowGroupFrame*)childFrame)->GetMaxColumns(rgColCount);
      aMaxColumns = PR_MAX(aMaxColumns, rgColCount);
    }

    GetNextFrame(childFrame, &childFrame);
  }
  return NS_OK;
}

nsresult
nsTableRowGroupFrame::InitRepeatedFrame(nsTableRowGroupFrame* aHeaderFooterFrame)
{
  nsIFrame* originalRowFrame;
  nsIFrame* copyRowFrame = GetFirstFrame();

  aHeaderFooterFrame->FirstChild(nsnull, &originalRowFrame);
  while (copyRowFrame) {
    // Set the row frame index
    int rowIndex = ((nsTableRowFrame*)originalRowFrame)->GetRowIndex();
    ((nsTableRowFrame*)copyRowFrame)->SetRowIndex(rowIndex);

    // For each table cell frame set its column index
    nsIFrame* originalCellFrame;
    nsIFrame* copyCellFrame;
    originalRowFrame->FirstChild(nsnull, &originalCellFrame);
    copyRowFrame->FirstChild(nsnull, &copyCellFrame);
    while (copyCellFrame) {
      nsIAtom*  frameType;
      copyCellFrame->GetFrameType(&frameType);

      if (nsLayoutAtoms::tableCellFrame == frameType) {
  #ifdef NS_DEBUG
        nsIContent* content1;
        nsIContent* content2;
        originalCellFrame->GetContent(&content1);
        copyCellFrame->GetContent(&content2);
        NS_ASSERTION(content1 == content2, "cell frames have different content");
        NS_IF_RELEASE(content1);
        NS_IF_RELEASE(content2);
  #endif
        PRInt32 colIndex;
        ((nsTableCellFrame*)originalCellFrame)->GetColIndex(colIndex);
        ((nsTableCellFrame*)copyCellFrame)->InitCellFrame(colIndex);
      }
      NS_IF_RELEASE(frameType);

      // Move to the next cell frame
      copyCellFrame->GetNextSibling(&copyCellFrame);
      originalCellFrame->GetNextSibling(&originalCellFrame);
    }

    // Move to the next row frame
    GetNextFrame(originalRowFrame, &originalRowFrame);
    GetNextFrame(copyRowFrame, &copyRowFrame);
  }

  return NS_OK;
}

NS_METHOD nsTableRowGroupFrame::Paint(nsIPresContext&      aPresContext,
                                      nsIRenderingContext& aRenderingContext,
                                      const nsRect&        aDirtyRect,
                                      nsFramePaintLayer    aWhichLayer)
{
  nsresult rv;
  if (NS_FRAME_PAINT_LAYER_BACKGROUND == aWhichLayer) {
    nsCompatibility mode;
    aPresContext.GetCompatibilityMode(&mode);
    if (eCompatibility_Standard == mode) {
      const nsStyleDisplay* disp =
        (const nsStyleDisplay*)mStyleContext->GetStyleData(eStyleStruct_Display);
      if (disp->mVisible) {
        const nsStyleSpacing* spacing =
          (const nsStyleSpacing*)mStyleContext->GetStyleData(eStyleStruct_Spacing);
        const nsStyleColor* color =
          (const nsStyleColor*)mStyleContext->GetStyleData(eStyleStruct_Color);
        nsTableFrame* tableFrame = nsnull;
        rv = nsTableFrame::GetTableFrame(this, tableFrame);
        if (NS_FAILED(rv) || (nsnull == tableFrame)) {
          return rv;
        }
        nscoord halfCellSpacingY = 
          NSToCoordRound(((float)tableFrame->GetCellSpacingY()) / (float)2);
        // every row group is short by the ending cell spacing X
        nsRect rect(0, 0, mRect.width, mRect.height);
        nsIFrame* firstRowGroup = nsnull;
        tableFrame->FirstChild(nsnull, &firstRowGroup);
        // first row group may have gotten too much cell spacing Y
        if (tableFrame->GetRowCount() != 1) {
          if (this == firstRowGroup) { 
            rect.height -= halfCellSpacingY;
          }
          else {
            rect.height += halfCellSpacingY;
            rect.y      -= halfCellSpacingY;
          }
        }

        nsCSSRendering::PaintBackground(aPresContext, aRenderingContext, this,
                                        aDirtyRect, rect, *color, *spacing, 0, 0);
      }
    }
  }
  // for debug...
  if ((NS_FRAME_PAINT_LAYER_DEBUG == aWhichLayer) && GetShowFrameBorders()) {
    aRenderingContext.SetColor(NS_RGB(0,255,0));
    aRenderingContext.DrawRect(0, 0, mRect.width, mRect.height);
  }

  PaintChildren(aPresContext, aRenderingContext, aDirtyRect, aWhichLayer);
  return NS_OK;
  /*nsFrame::Paint(aPresContext, aRenderingContext, aDirtyRect, aWhichLayer);*/

}

PRIntn
nsTableRowGroupFrame::GetSkipSides() const
{
  PRIntn skip = 0;
  if (nsnull != mPrevInFlow) {
    skip |= 1 << NS_SIDE_TOP;
  }
  if (nsnull != mNextInFlow) {
    skip |= 1 << NS_SIDE_BOTTOM;
  }
  return skip;
}

// aDirtyRect is in our coordinate system
// child rect's are also in our coordinate system
/** overloaded method from nsContainerFrame.  The difference is that 
  * we don't want to clip our children, so a cell can do a rowspan
  */
void nsTableRowGroupFrame::PaintChildren(nsIPresContext&      aPresContext,
                                         nsIRenderingContext& aRenderingContext,
                                         const nsRect&        aDirtyRect,
                                         nsFramePaintLayer    aWhichLayer)
{
  nsIFrame* kid = GetFirstFrame();
  while (nsnull != kid) {
    nsIView *pView;
     
    kid->GetView(&pView);
    if (nsnull == pView) {
      PRBool clipState;
      nsRect kidRect;
      kid->GetRect(kidRect);
      nsRect damageArea(aDirtyRect);
      // Translate damage area into kid's coordinate system
      nsRect kidDamageArea(damageArea.x - kidRect.x, damageArea.y - kidRect.y,
                           damageArea.width, damageArea.height);
      aRenderingContext.PushState();
      aRenderingContext.Translate(kidRect.x, kidRect.y);
      kid->Paint(aPresContext, aRenderingContext, kidDamageArea, aWhichLayer);
      if ((NS_FRAME_PAINT_LAYER_DEBUG == aWhichLayer) &&
          GetShowFrameBorders()) {
        aRenderingContext.SetColor(NS_RGB(255,0,0));
        aRenderingContext.DrawRect(0, 0, kidRect.width, kidRect.height);
      }
      aRenderingContext.PopState(clipState);
    }
    GetNextFrame(kid, &kid);
  }
}

/* we overload this here because rows have children that can span outside of themselves.
 * so the default "get the child rect, see if it contains the event point" action isn't
 * sufficient.  We have to ask the row if it has a child that contains the point.
 */
NS_IMETHODIMP
nsTableRowGroupFrame::GetFrameForPoint(const nsPoint& aPoint, nsIFrame** aFrame)
{
  nsIFrame* kid;
  nsRect kidRect;
  nsPoint tmp;
  *aFrame = this;

  FirstChild(nsnull, &kid);
  while (nsnull != kid) {
    kid->GetRect(kidRect);
    const nsStyleDisplay *childDisplay;
    kid->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay) {
      if (((nsTableRowFrame*)(kid))->Contains(aPoint)) {
        tmp.MoveTo(aPoint.x - kidRect.x, aPoint.y - kidRect.y);
        return kid->GetFrameForPoint(tmp, aFrame);
      }
    }
    else {
      if (kidRect.Contains(aPoint)) {
        tmp.MoveTo(aPoint.x - kidRect.x, aPoint.y - kidRect.y);
        return kid->GetFrameForPoint(tmp, aFrame);
      }
    }

    GetNextFrame(kid, &kid);
  }
  return NS_ERROR_FAILURE;
}

// Position and size aKidFrame and update our reflow state. The origin of
// aKidRect is relative to the upper-left origin of our frame
void nsTableRowGroupFrame::PlaceChild(nsIPresContext&      aPresContext,
																			RowGroupReflowState& aReflowState,
																			nsIFrame*            aKidFrame,
																			const nsRect&        aKidRect,
																			nsSize*              aMaxElementSize,
																			nsSize&              aKidMaxElementSize)
{
  // Place and size the child
  aKidFrame->SetRect(aKidRect);

  // Adjust the running y-offset
  aReflowState.y += aKidRect.height;

  // If our height is constrained then update the available height
  if (PR_FALSE == aReflowState.unconstrainedHeight) {
    aReflowState.availSize.height -= aKidRect.height;
  }

  // Update the maximum element size
  if (PR_TRUE==aReflowState.firstRow)
  {
    aReflowState.firstRow = PR_FALSE;
    if (nsnull != aMaxElementSize) {
      aMaxElementSize->width = aKidMaxElementSize.width;
      aMaxElementSize->height = aKidMaxElementSize.height;
    }
  }
  else if (nsnull != aMaxElementSize) {
      aMaxElementSize->width = PR_MAX(aMaxElementSize->width, aKidMaxElementSize.width);
  }
}

/**
 * Reflow the frames we've already created
 *
 * @param   aPresContext presentation context to use
 * @param   aReflowState current inline state
 * @return  true if we successfully reflowed all the mapped children and false
 *            otherwise, e.g. we pushed children to the next in flow
 */
NS_METHOD nsTableRowGroupFrame::ReflowMappedChildren(nsIPresContext&      aPresContext,
                                                     nsHTMLReflowMetrics& aDesiredSize,
                                                     RowGroupReflowState& aReflowState,
                                                     nsReflowStatus&      aStatus,
                                                     nsTableRowFrame *    aStartFrame,
                                                     nsReflowReason       aReason,
                                                     PRBool               aDoSiblings,
                                                     PRBool               aDirtyOnly)
{
  nsSize    kidMaxElementSize;
  nsSize*   pKidMaxElementSize = (nsnull != aDesiredSize.maxElementSize) ? &kidMaxElementSize : nsnull;
  nsresult  rv = NS_OK;

  if (!ContinueReflow(aPresContext, aReflowState.y, aReflowState.availSize.height))
      return rv;

  nsIFrame*  kidFrame;
  if (nsnull==aStartFrame) {
    kidFrame = GetFirstFrameForReflow(aPresContext);
    ReflowBeforeRowLayout(aPresContext, aDesiredSize, aReflowState, aStatus, aReason);
  }
  else
    kidFrame = aStartFrame;
                   
  PRUint8 borderStyle = aReflowState.tableFrame->GetBorderCollapseStyle();
 
  for ( ; nsnull != kidFrame; ) 
  {
    // Get the frame state bits
    nsFrameState  frameState;
    kidFrame->GetFrameState(&frameState);

    // See if we should only reflow the dirty child frames
    PRBool  doReflowChild = PR_TRUE;
    if (aDirtyOnly) {
      if ((frameState & NS_FRAME_IS_DIRTY) == 0) {
        doReflowChild = PR_FALSE;
      }
    }

    // Reflow the row frame
    if (doReflowChild) {
      nsSize kidAvailSize(aReflowState.availSize);
      if (0>=kidAvailSize.height)
        kidAvailSize.height = 1;      // XXX: HaCk - we don't handle negative heights yet
      nsHTMLReflowMetrics desiredSize(pKidMaxElementSize);
      desiredSize.width=desiredSize.height=desiredSize.ascent=desiredSize.descent=0;
  
      // Reflow the child into the available space, giving it as much room as
      // it wants. We'll deal with splitting later after we've computed the row
      // heights, taking into account cells with row spans...
      kidAvailSize.height = NS_UNCONSTRAINEDSIZE;
      nsReflowReason  reason = aReason;
      if (aDirtyOnly) {
        if (frameState & NS_FRAME_FIRST_REFLOW) {
          // Newly inserted frame
          reason = eReflowReason_Initial;
        }
      }
      nsHTMLReflowState kidReflowState(aPresContext, aReflowState.reflowState, kidFrame,
                                       kidAvailSize, reason);
     
      // If this isn't the first row frame, then we can't be at the top of
      // the page anymore...
      if (kidFrame != GetFirstFrame()) {
        kidReflowState.isTopOfPage = PR_FALSE;
      }

      if (aReflowState.tableFrame->RowGroupsShouldBeConstrained()) {
        // Only applies to the tree widget.
        const nsStyleDisplay *rowDisplay;
        kidFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)rowDisplay));
        if (NS_STYLE_DISPLAY_TABLE_ROW_GROUP == rowDisplay->mDisplay &&
            aReflowState.availSize.height != NS_UNCONSTRAINEDSIZE) {
          kidReflowState.availableHeight = aReflowState.availSize.height;
        }
      }
  
      rv = ReflowChild(kidFrame, aPresContext, desiredSize, kidReflowState, aStatus);
  
      // Place the child
      nsRect kidRect (0, aReflowState.y, desiredSize.width, desiredSize.height);
      PlaceChild(aPresContext, aReflowState, kidFrame, kidRect, aDesiredSize.maxElementSize,
                 kidMaxElementSize);
  
      /* if the table has collapsing borders, we need to reset the length of the shared vertical borders
       * for the table and the cells that overlap this row
       */
      if ((eReflowReason_Initial != aReflowState.reflowState.reason) && (NS_STYLE_BORDER_COLLAPSE==borderStyle))
      {
        const nsStyleDisplay *childDisplay;
        kidFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
        if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
        {
          PRInt32 rowIndex = ((nsTableRowFrame*)kidFrame)->GetRowIndex();
          aReflowState.tableFrame->SetBorderEdgeLength(NS_SIDE_LEFT,
                                                       rowIndex,
                                                       kidRect.height);
          aReflowState.tableFrame->SetBorderEdgeLength(NS_SIDE_RIGHT,
                                                       rowIndex,
                                                       kidRect.height);
          PRInt32 colCount = aReflowState.tableFrame->GetColCount();
          PRInt32 colIndex = 0;
          nsIFrame *cellFrame;
          for (colIndex = 0; colIndex < colCount; colIndex++) {
            cellFrame = aReflowState.tableFrame->GetCellInfoAt(rowIndex, colIndex);
            if (cellFrame) {
              const nsStyleDisplay *cellDisplay;
              cellFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)cellDisplay));
              if (NS_STYLE_DISPLAY_TABLE_CELL == cellDisplay->mDisplay) {
                ((nsTableCellFrame *)(cellFrame))->SetBorderEdgeLength(NS_SIDE_LEFT,
                                                                       rowIndex,
                                                                       kidRect.height);
                ((nsTableCellFrame *)(cellFrame))->SetBorderEdgeLength(NS_SIDE_RIGHT,
                                                                       rowIndex,
                                                                       kidRect.height);
              }
            }
          }
        }
      }
    } else {
      // Adjust the running y-offset so we know where the next row should
      // be placed
      nsSize  kidSize;

      kidFrame->GetSize(kidSize);
      aReflowState.y += kidSize.height;
    }

    if (PR_FALSE==aDoSiblings)
      break;

    if (!ContinueReflow(aPresContext, aReflowState.y, aReflowState.availSize.height))
      break;

    // Get the next child
    GetNextFrameForReflow(aPresContext, kidFrame, &kidFrame);
  }

  // Call our post-row reflow hook
  ReflowAfterRowLayout(aPresContext, aDesiredSize, aReflowState, aStatus, aReason);
  return rv;
}

/**
 * Pull-up all the row frames from our next-in-flow
 */
NS_METHOD nsTableRowGroupFrame::PullUpAllRowFrames(nsIPresContext& aPresContext)
{
  if (mNextInFlow) {
    nsTableRowGroupFrame* nextInFlow = (nsTableRowGroupFrame*)mNextInFlow;
  
    while (nsnull != nextInFlow) {
      // Any frames on the next-in-flow's overflow list?
      if (nextInFlow->mOverflowFrames.NotEmpty()) {
        // Yes, append them to its child list
        nextInFlow->mFrames.AppendFrames(nextInFlow, nextInFlow->mOverflowFrames);
      }

      // Any row frames?
      if (nextInFlow->mFrames.NotEmpty()) {
        // When pushing and pulling frames we need to check for whether any
        // views need to be reparented.
        for (nsIFrame* f = nextInFlow->GetFirstFrame(); f; GetNextFrame(f, &f)) {
          nsHTMLContainerFrame::ReparentFrameView(f, nextInFlow, this);
        }
        // Append them to our child list
        mFrames.AppendFrames(this, nextInFlow->mFrames);
      }

      // Move to the next-in-flow        
      nextInFlow->GetNextInFlow((nsIFrame**)&nextInFlow);
    }
  }

  return NS_OK;
}

void nsTableRowGroupFrame::GetNextRowSibling(nsIFrame** aRowFrame)
{
  GetNextFrame(*aRowFrame, aRowFrame);
  while(*aRowFrame) {
    const nsStyleDisplay *display;
    (*aRowFrame)->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)display));
    if (NS_STYLE_DISPLAY_TABLE_ROW == display->mDisplay) {
      return;
    }
    GetNextFrame(*aRowFrame, aRowFrame);
  }
}

/* CalculateRowHeights provides default heights for all rows in the rowgroup.
 * Actual row heights are ultimately determined by the table, when the table
 * height attribute is factored in.
 */
void nsTableRowGroupFrame::CalculateRowHeights(nsIPresContext& aPresContext, 
                                               nsHTMLReflowMetrics& aDesiredSize,
                                               const nsHTMLReflowState& aReflowState)
{
  nsTableFrame *tableFrame=nsnull;
  nsresult rv = nsTableFrame::GetTableFrame(this, tableFrame);
  if (NS_FAILED(rv) || nsnull==tableFrame)
    return;
  // all table cells have the same top and bottom margins, namely cellSpacingY
  nscoord cellSpacingY = tableFrame->GetCellSpacingY();

  // iterate children and for each row get the height of the tallest cell. Keep
  // track of whether any of the rows have a cell that spans into the row
  PRBool  hasRowSpanningCell = PR_FALSE;
  PRInt32 numRows;
  GetRowCount(numRows, PR_FALSE);
  nscoord *rowHeights = new nscoord[numRows];
  nsCRT::memset (rowHeights, 0, numRows*sizeof(nscoord));

  /* Step 1:  get the height of the tallest cell in the row and save it for
   *          pass 2. This height is for table cells that originate in this
   *          row and that don't span into the rows that follow
   */
  nsIFrame* rowFrame = GetFirstFrame();
  PRInt32 rowIndex = 0;

  // For row groups that are split across pages, the first row frame won't
  // necessarily be index 0
  PRInt32 startRowIndex = -1;
  const nsStyleDisplay *childDisplay;
  while (nsnull != rowFrame)
  {
    rowFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
    {
      if (startRowIndex == -1) {
        startRowIndex = ((nsTableRowFrame*)rowFrame)->GetRowIndex();
      }

      // get the height of the tallest cell in the row (excluding cells that span rows)
      // XXX GetChildMaxTopMargin and GetChildMaxBottomMargin should be removed/simplified because
      // according to CSS, all table cells must have the same top/bottom and left/right margins.
      nscoord maxCellHeight       = ((nsTableRowFrame*)rowFrame)->GetTallestChild();
      nscoord maxCellTopMargin    = ((nsTableRowFrame*)rowFrame)->GetChildMaxTopMargin();
      nscoord maxCellBottomMargin = ((nsTableRowFrame*)rowFrame)->GetChildMaxBottomMargin();
      nscoord maxRowHeight = maxCellHeight + maxCellTopMargin + maxCellBottomMargin;
      // only the top row has a top margin. Other rows start at the bottom of the prev row's bottom margin.
      // save the row height for pass 2 below
      rowHeights[rowIndex] = maxRowHeight;

      // See if a cell spans into the row. If so we'll have to do step 2
      if (!hasRowSpanningCell) {
        if (tableFrame->RowIsSpannedInto(rowIndex + startRowIndex)) {
          hasRowSpanningCell = PR_TRUE;
        }
      }
      rowIndex++;
    }
    // Get the next row
    GetNextFrame(rowFrame, &rowFrame);
  }
  

  /* Step 2:  Now account for cells that span rows. We only do this if there are cells
   *          that span rows.
   *          A spanning cell's height is the sum of the heights of the rows it spans,
   *          or it's own desired height, whichever is greater.
   *          If the cell's desired height is the larger value, resize the rows and contained
   *          cells by an equal percentage of the additional space.
   *          We go through this loop twice.  The first time, we are adjusting cell heights
   *          on the fly.
   *          The second time through the loop, we're ensuring that subsequent row-spanning cells
   *          didn't change prior calculations.  
   *          Since we are guaranteed to have found the max height spanners the first time through, 
   *          we know we only need two passes, not an arbitrary number.
   */
  if (hasRowSpanningCell) {
    nscoord deltaY = 0;
    for (PRInt32 counter=0; counter<2; counter++)
    {
      rowFrame = GetFirstFrame();
      rowIndex = 0;
      while (nsnull != rowFrame)
      {
        rowFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
        if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
        {
          // check this row for a cell with rowspans
          nsIFrame *cellFrame;
          rowFrame->FirstChild(nsnull, &cellFrame);
          while (nsnull != cellFrame)
          {
            const nsStyleDisplay *cellChildDisplay;
            cellFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)cellChildDisplay));
            if (NS_STYLE_DISPLAY_TABLE_CELL == cellChildDisplay->mDisplay)
            {
              PRInt32 rowSpan = tableFrame->GetEffectiveRowSpan(rowIndex + startRowIndex,
                                                                (nsTableCellFrame*)cellFrame);
              if (rowSpan > 1)
              { // found a cell with rowspan > 1, determine the height of the rows it
                // spans
                nscoord heightOfRowsSpanned = 0;
                PRInt32 i;
                for (i = 0; i < rowSpan; i++) {
                  heightOfRowsSpanned += rowHeights[rowIndex + i];
                }
                // reduce the height by top and bottom margins
                nscoord availHeightOfRowsSpanned = heightOfRowsSpanned - cellSpacingY - cellSpacingY;
  
                // see if the cell's height fits within the rows it spans. If this is
                // pass 1 then use the cell's desired height and not the current height
                // of its frame. That way this works for incremental reflow, too
                nsSize  cellFrameSize;
                cellFrame->GetSize(cellFrameSize);
                if (0 == counter) {
                  nsSize cellDesiredSize = ((nsTableCellFrame*)cellFrame)->GetDesiredSize();
                  cellFrameSize.height = cellDesiredSize.height;
                }
  
                if (availHeightOfRowsSpanned >= cellFrameSize.height)
                {
                  // yes the cell's height fits with the available space of the rows it
                  // spans. Set the cell frame's height
                  cellFrame->SizeTo(cellFrameSize.width, availHeightOfRowsSpanned);
                  // Realign cell content based on new height
                  ((nsTableCellFrame*)cellFrame)->VerticallyAlignChild();
                }
                else
                {
                  // the cell's height is larger than the available space of the rows it
                  // spans so distribute the excess height to the rows affected
                  PRInt32 excessHeight = cellFrameSize.height - availHeightOfRowsSpanned;
  
                  // for every row starting at the row with the spanning cell and down
                  // to the last row spanned by the cell
                  nsTableRowFrame *rowFrameToBeResized = (nsTableRowFrame *)rowFrame;
                  nscoord excessAllocated = 0;
                  for (i = rowIndex; i < (rowIndex + rowSpan); i++) {
                    // The amount of additional space each row gets is based on the
                    // percentage of space it occupies, i.e. they don't all get the
                    // same amount of available space
                    float percent = ((float)rowHeights[i]) / ((float)heightOfRowsSpanned);
                    
                    // give rows their percentage, except for the last row which gets
                    // the remainder
                    nscoord excessForRow = ((i + 1) == (rowIndex + rowSpan)) ?
                                           excessHeight - excessAllocated  :
                                           NSToCoordRound(((float)(excessHeight)) * percent);
                    excessAllocated += excessForRow;
  
                    // update the row height
                    rowHeights[i] += excessForRow;
  
                    // Get the next row frame
                    GetNextRowSibling((nsIFrame**)&rowFrameToBeResized);
                  }
                  NS_ASSERTION(excessAllocated == excessHeight, "excess distribution failed");
                }
              }
            }
            // Get the next row child (cell frame)
            cellFrame->GetNextSibling(&cellFrame);
          }
  
          // If this is pass 2 then resize the row to its final size and move the
          // row's position if the previous rows have caused a shift
          if (1 == counter) {
            nsRect  rowBounds;
            rowFrame->GetRect(rowBounds);
  
            // Move the row to the correct position
            rowBounds.y += deltaY;
  
            // Adjust our running delta
            deltaY += rowHeights[rowIndex] - rowBounds.height;
  
            // Resize the row to its final size and position
            rowBounds.height = rowHeights[rowIndex];
            rowFrame->SetRect(rowBounds);
          }
          
          rowIndex++;
        }
  
        // Get the next rowgroup child (row frame)
        GetNextFrame(rowFrame, &rowFrame);
      }
    }
  }

  // step 3: notify the rows of their new heights
  nscoord rowGroupHeight = 0;
  rowFrame = GetFirstFrame();
  rowIndex = 0;
  while (nsnull != rowFrame)
  {
    rowFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
    {
      // Notify the row of the new size
      ((nsTableRowFrame *)rowFrame)->DidResize(aPresContext, aReflowState);
    }

    // Update the running row group height. The height includes frames that
    // aren't rows as well
    nsSize  rowSize;
    rowFrame->GetSize(rowSize);
    rowGroupHeight += rowSize.height;

    // Get the next row
    GetNextFrame(rowFrame, &rowFrame);
    rowIndex++;
  }

  // Adjust our desired size
  aDesiredSize.height = rowGroupHeight;

  // cleanup
  delete []rowHeights;
}

// Called by IR_TargetIsChild() to adjust the sibling frames that follow
// after an incremental reflow of aKidFrame.
// This function is not used for paginated mode so we don't need to deal
// with continuing frames, and it's only called if aKidFrame has no
// cells that span into it and no cells that span across it. That way
// we don't have to deal with rowspans
nsresult
nsTableRowGroupFrame::AdjustSiblingsAfterReflow(nsIPresContext&      aPresContext,
                                                RowGroupReflowState& aReflowState,
                                                nsIFrame*            aKidFrame,
                                                nsSize*              aMaxElementSize,
                                                nscoord              aDeltaY)
{
  NS_PRECONDITION(NS_UNCONSTRAINEDSIZE == aReflowState.reflowState.availableHeight,
                  "we're not in galley mode");
  nsIFrame* lastKidFrame = aKidFrame;

  // Move the frames that follow aKidFrame by aDeltaY and update the max element
  // size
  nsIFrame* kidFrame;
  for (aKidFrame->GetNextSibling(&kidFrame); kidFrame; kidFrame->GetNextSibling(&kidFrame)) {
    // Update the max element size
    if (aMaxElementSize) {
      nsSize kidMaxElementSize;
      ((nsTableRowFrame*)kidFrame)->GetMaxElementSize(kidMaxElementSize);
      
      aMaxElementSize->width = PR_MAX(aMaxElementSize->width, kidMaxElementSize.width);
    }

    // Move the frame if we need to
    if (aDeltaY != 0) {
      nsPoint origin;
  
      // Adjust the y-origin
      kidFrame->GetOrigin(origin);
      origin.y += aDeltaY;
  
      nsIHTMLReflow* htmlReflow;
      if (NS_OK == kidFrame->QueryInterface(kIHTMLReflowIID, (void**)&htmlReflow)) {
        htmlReflow->WillReflow(aPresContext);
      }
      
      kidFrame->MoveTo(origin.x, origin.y);
    }

    // Remember the last frame
    lastKidFrame = kidFrame;
  }

  // Update our running y-offset to reflect the bottommost child
  nsRect  rect;
  lastKidFrame->GetRect(rect);
  aReflowState.y = rect.YMost();

  return NS_OK;
}

nsresult
nsTableRowGroupFrame::SplitRowGroup(nsIPresContext&          aPresContext,
                                    nsHTMLReflowMetrics&     aDesiredSize,
                                    const nsHTMLReflowState& aReflowState,
                                    nsTableFrame*            aTableFrame,
                                    nsReflowStatus&          aStatus)
{
  nsIFrame* prevRowFrame = nsnull;
  nsresult  rv = NS_OK;

  // Walk each of the row frames looking for the first row frame that
  // doesn't fit in the available space
  for (nsIFrame* rowFrame = GetFirstFrame(); rowFrame; GetNextFrame(rowFrame, &rowFrame)) {
    nsRect  bounds;

    rowFrame->GetRect(bounds);
    if (bounds.YMost() > aReflowState.availableHeight) {
      // If this is the first row frame then we need to split it
      if (!prevRowFrame) {
        // Reflow the row in the available space and have it split
        nsSize              availSize(aReflowState.availableWidth,
                                      aReflowState.availableHeight - bounds.y);
        nsHTMLReflowState   rowReflowState(aPresContext, aReflowState, rowFrame,
                                          availSize, eReflowReason_Resize);
        nsHTMLReflowMetrics desiredSize(nsnull);

        rv = ReflowChild(rowFrame, aPresContext, desiredSize, rowReflowState, aStatus);
        rowFrame->SizeTo(desiredSize.width, desiredSize.height);
        ((nsTableRowFrame *)rowFrame)->DidResize(aPresContext, aReflowState);
        aDesiredSize.height = desiredSize.height;

        if (NS_FRAME_IS_NOT_COMPLETE(aStatus)) {
#ifdef NS_DEBUG
          // Verify it doesn't already have a next-in-flow. The reason it should
          // not already have a next-in-flow is that ReflowMappedChildren() reflows
          // the row frames with an unconstrained available height
          nsIFrame* nextInFlow;
          rowFrame->GetNextInFlow(&nextInFlow);
          NS_ASSERTION(!nextInFlow, "row frame already has next-in-flow");
#endif
          // Create a continuing frame, add it to the child list, and then push it
          // and the frames that follow
          nsIFrame*        contRowFrame;
          nsIPresShell*    presShell;
          nsIStyleSet*     styleSet;
          
          aPresContext.GetShell(&presShell);
          presShell->GetStyleSet(&styleSet);
          NS_RELEASE(presShell);
          styleSet->CreateContinuingFrame(&aPresContext, rowFrame, this, &contRowFrame);
          NS_RELEASE(styleSet);
  
          // Add it to the child list
          nsIFrame* nextRow;
          GetNextFrame(rowFrame, &nextRow);
          GetNextFrame(contRowFrame, &nextRow);
          GetNextFrame(rowFrame, &contRowFrame);
          
          // Push the continuing row frame and the frames that follow
          PushChildren(contRowFrame, rowFrame);
          aStatus = NS_FRAME_NOT_COMPLETE;

        } else {
          // The row frame is complete. It may be the case that it's minimum
          // height was greater than the available height we gave it
          nsIFrame* nextRowFrame;

          // Push the frame that follows
          GetNextFrame(rowFrame, &nextRowFrame);
          
          if (nextRowFrame) {
            PushChildren(nextRowFrame, rowFrame);
          }
          aStatus = nextRowFrame ? NS_FRAME_NOT_COMPLETE : NS_FRAME_COMPLETE;
        }

      } else {
        // See whether the row frame has cells that span into it
        PRInt32           rowIndex = ((nsTableRowFrame*)rowFrame)->GetRowIndex();
        PRInt32           colCount = aTableFrame->GetColCount();
        nsTableCellFrame* prevCellFrame = nsnull;

        for (PRInt32 colIndex = 0; colIndex < colCount; colIndex++) {
          nsTableCellFrame* cellFrame = aTableFrame->GetCellInfoAt(rowIndex, colIndex);
          NS_ASSERTION(cellFrame, "no cell frame");

          // See if the cell frame is really in this row, or whether it's a
          // row span from a previous row
          PRInt32 realRowIndex;
          cellFrame->GetRowIndex(realRowIndex);
          if (realRowIndex == rowIndex) {
            prevCellFrame = cellFrame;
          } else {
            // This cell frame spans into the row we're pushing, so we need to:
            // - reflow the cell frame into the new smaller space
            // - create a continuing frame for the cell frame (we do this regardless
            //   of whether it's complete)
            // - add the continuing frame to the row frame we're pushing
            nsIFrame*         parentFrame;
            nsPoint           firstRowOrigin, lastRowOrigin;
            nsReflowStatus    status;

            // Ask the cell frame's parent to reflow it to the height of all the
            // rows it spans between its parent frame and the row we're pushing
            cellFrame->GetParent(&parentFrame);
            parentFrame->GetOrigin(firstRowOrigin);
            rowFrame->GetOrigin(lastRowOrigin);
            ((nsTableRowFrame*)parentFrame)->ReflowCellFrame(aPresContext,
              aReflowState, cellFrame, lastRowOrigin.y - firstRowOrigin.y, status);
            
            // Create the continuing cell frame
            nsIFrame*         contCellFrame;
            nsIPresShell*     presShell;
            nsIStyleSet*      styleSet;

            aPresContext.GetShell(&presShell);
            presShell->GetStyleSet(&styleSet);
            NS_RELEASE(presShell);
            styleSet->CreateContinuingFrame(&aPresContext, cellFrame, rowFrame, &contCellFrame);
            NS_RELEASE(styleSet);

            // Add it to the row's child list
            ((nsTableRowFrame*)rowFrame)->InsertCellFrame((nsTableCellFrame*)contCellFrame,
                                                          prevCellFrame);
            prevCellFrame = (nsTableCellFrame*)contCellFrame;
          }
        }

        // Push this row frame and those that follow to the next-in-flow
        PushChildren(rowFrame, prevRowFrame);
        aStatus = NS_FRAME_NOT_COMPLETE;
        aDesiredSize.height = bounds.y;
      }

      break;
    }

    prevRowFrame = rowFrame;
  }

  return NS_OK;
}

/** Layout the entire row group.
  * This method stacks rows vertically according to HTML 4.0 rules.
  * Rows are responsible for layout of their children.
  */
NS_METHOD
nsTableRowGroupFrame::Reflow(nsIPresContext&          aPresContext,
                             nsHTMLReflowMetrics&     aDesiredSize,
                             const nsHTMLReflowState& aReflowState,
                             nsReflowStatus&          aStatus)
{
  if (nsDebugTable::gRflRowGrp) nsTableFrame::DebugReflow("TRG::Rfl", this, &aReflowState, nsnull);
  nsresult rv=NS_OK;

  // Initialize out parameter
  if (nsnull != aDesiredSize.maxElementSize) {
    aDesiredSize.maxElementSize->width = 0;
    aDesiredSize.maxElementSize->height = 0;
  }

  nsTableFrame *tableFrame=nsnull;
  rv = nsTableFrame::GetTableFrame(this, tableFrame);
  if (NS_FAILED(rv))
    return rv;
  else if (tableFrame == nsnull)
    return NS_ERROR_NULL_POINTER;

  RowGroupReflowState state(aPresContext, aReflowState, tableFrame);

  if (eReflowReason_Incremental == aReflowState.reason) {
    rv = IncrementalReflow(aPresContext, aDesiredSize, state, aStatus);
  } else {
    aStatus = NS_FRAME_COMPLETE;
  
    // Check for an overflow list
    MoveOverflowToChildList();
  
    // Reflow the existing frames. Before we do, pull-up any row frames from
    // our next-in-flow.
    // XXX It would be more efficient to do this if we have room left after
    // reflowing the frames we have, the problem is we don't know if we have
    // room left until after we call CalculateRowHeights()...
    PullUpAllRowFrames(aPresContext);
    rv = ReflowMappedChildren(aPresContext, aDesiredSize, state, aStatus,
                                nsnull, aReflowState.reason, PR_TRUE);
  
    // Return our desired rect
    aDesiredSize.width = aReflowState.availableWidth;
    aDesiredSize.height = state.y;

    // account for scroll bars. XXX needs optimization/caching
    if (nsnull != aDesiredSize.maxElementSize) {
      nsIAtom* pseudoTag;
 
      mStyleContext->GetPseudoType(pseudoTag);
      if (pseudoTag == nsLayoutAtoms::scrolledContentPseudo) {
        nsIFrame* scrollFrame;
        GetParent(&scrollFrame);
        const nsStyleDisplay *display;
        scrollFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)display));
        if ((NS_STYLE_OVERFLOW_SCROLL == display->mOverflow) ||
            (NS_STYLE_OVERFLOW_AUTO   == display->mOverflow)) {
          float sbWidth, sbHeight;
          nsCOMPtr<nsIDeviceContext> dc;
          aPresContext.GetDeviceContext(getter_AddRefs(dc));

          dc->GetScrollBarDimensions(sbWidth, sbHeight);
          aDesiredSize.maxElementSize->width += NSToCoordRound(sbWidth);
          // If scrollbars are always visible then add in the hor sb height 
          if (NS_STYLE_OVERFLOW_SCROLL == display->mOverflow) {
            aDesiredSize.maxElementSize->height += NSToCoordRound(sbHeight);
          }
        }
      }
      NS_IF_RELEASE(pseudoTag);
    }

    // shrink wrap rows to height of tallest cell in that row
    if (eReflowReason_Initial != aReflowState.reason) {
      CalculateRowHeights(aPresContext, aDesiredSize, aReflowState);
    }

    // See if all the frames fit
    if (aDesiredSize.height > aReflowState.availableHeight && 
        !tableFrame->RowGroupsShouldBeConstrained()) {
      // Nope, find a place to split the row group
      SplitRowGroup(aPresContext, aDesiredSize, aReflowState, tableFrame, aStatus);
    }
  }

  // If we computed our max element element size, then cache it so we can return
  // it later when asked
  if (aDesiredSize.maxElementSize) {
    mMaxElementSize = *aDesiredSize.maxElementSize;
  }
  
  if (nsDebugTable::gRflRowGrp) nsTableFrame::DebugReflow("TRG::Rfl ex", this, nsnull, &aDesiredSize);
  return rv;
}


NS_METHOD nsTableRowGroupFrame::IncrementalReflow(nsIPresContext& aPresContext,
                                                  nsHTMLReflowMetrics& aDesiredSize,
                                                  RowGroupReflowState& aReflowState,
                                                  nsReflowStatus& aStatus)
{
  nsresult  rv = NS_OK;

  // determine if this frame is the target or not
  nsIFrame *target=nsnull;
  rv = aReflowState.reflowState.reflowCommand->GetTarget(target);
  if ((PR_TRUE==NS_SUCCEEDED(rv)) && (nsnull!=target))
  {
    if (this==target)
      rv = IR_TargetIsMe(aPresContext, aDesiredSize, aReflowState, aStatus);
    else
    {
      // Get the next frame in the reflow chain
      nsIFrame* nextFrame;
      aReflowState.reflowState.reflowCommand->GetNext(nextFrame);

      rv = IR_TargetIsChild(aPresContext, aDesiredSize, aReflowState, aStatus, nextFrame);
    }
  }
  return rv;
}

// Helper function. It marks the table frame as dirty and generates
// a reflow command
nsresult
nsTableRowGroupFrame::AddTableDirtyReflowCommand(nsIPresContext& aPresContext,
                                                 nsIPresShell&   aPresShell,
                                                 nsIFrame*       aTableFrame)
{
  nsFrameState      frameState;
  nsIFrame*         tableParentFrame;
  nsIReflowCommand* reflowCmd;
  nsresult          rv;

  // Mark the table frame as dirty
  aTableFrame->GetFrameState(&frameState);
  frameState |= NS_FRAME_IS_DIRTY;
  aTableFrame->SetFrameState(frameState);

  // Target the reflow comamnd at its parent frame
  aTableFrame->GetParent(&tableParentFrame);
  rv = NS_NewHTMLReflowCommand(&reflowCmd, tableParentFrame,
                               nsIReflowCommand::ReflowDirty);
  if (NS_SUCCEEDED(rv)) {
    // Add the reflow command
    rv = aPresShell.AppendReflowCommand(reflowCmd);
    NS_RELEASE(reflowCmd);
  }

  return rv;
}

NS_IMETHODIMP
nsTableRowGroupFrame::AppendFrames(nsIPresContext& aPresContext,
                                   nsIPresShell&   aPresShell,
                                   nsIAtom*        aListName,
                                   nsIFrame*       aFrameList)
{
  // Get the table frame
  nsTableFrame* tableFrame;
  nsTableFrame::GetTableFrame(this, tableFrame);

  // Append the frames
  mFrames.AppendFrames(nsnull, aFrameList);

  // See if the newly appended rows are the last rows in the table. Don't
  // do this for appended row group frames. We probably should, but DidAppendRow()
  // doesn't handle row group frames
  const nsStyleDisplay *display;
  aFrameList->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)display));
  if ((NS_STYLE_DISPLAY_TABLE_ROW == display->mDisplay) && NoRowsFollow()) {
    // The rows we appended are the last rows in the table so incrementally
    // add them to the cell map
    for (nsIFrame* rowFrame = aFrameList; rowFrame; rowFrame->GetNextSibling(&rowFrame)) {
      DidAppendRow((nsTableRowFrame*)rowFrame);
    }

    // See if any implicit column frames need to be created as a result of
    // adding the new rows
    PRBool  createdColFrames;
    tableFrame->EnsureColumns(aPresContext, createdColFrames);
    if (createdColFrames) {
      // We need to rebuild the column cache
      // XXX It would be nice if this could be done incrementally
      tableFrame->InvalidateColumnCache();
    }

    // Reflow the new frames. They're already marked dirty, so generate a reflow
    // command that tells us to reflow our dirty child frames
    nsIReflowCommand* reflowCmd;

    if (NS_SUCCEEDED(NS_NewHTMLReflowCommand(&reflowCmd, this,
                                             nsIReflowCommand::ReflowDirty))) {
      aPresShell.AppendReflowCommand(reflowCmd);
      NS_RELEASE(reflowCmd);
    }

  } else {
    // We need to rebuild the cell map, because currently we can't insert
    // new frames except at the end (append)
    tableFrame->InvalidateCellMap();
    
    // We should try and avoid doing a pass1 reflow on all the cells and just
    // do it for the newly added frames, but we need to add these frames to the
    // cell map before we reflow them
    tableFrame->InvalidateFirstPassCache();

    // Because the number of columns may have changed invalidate the column
    // cache. Note that this has the side effect of recomputing the column
    // widths, so we don't need to call InvalidateColumnWidths()
    tableFrame->InvalidateColumnCache();

    // Generate a reflow command so we reflow the table itself. This will
    // do a pass-1 reflow of all the rows including any rows we just added
    AddTableDirtyReflowCommand(aPresContext, aPresShell, tableFrame);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsTableRowGroupFrame::InsertFrames(nsIPresContext& aPresContext,
                                   nsIPresShell&   aPresShell,
                                   nsIAtom*        aListName,
                                   nsIFrame*       aPrevFrame,
                                   nsIFrame*       aFrameList)
{
  // Get the table frame
  nsTableFrame* tableFrame = nsnull;
  nsTableFrame::GetTableFrame(this, tableFrame);

  // Insert the frames
  mFrames.InsertFrames(nsnull, aPrevFrame, aFrameList);

  // We need to rebuild the cell map, because currently we can't insert
  // new frames except at the end (append)
  tableFrame->InvalidateCellMap();

  // We should try and avoid doing a pass1 reflow on all the cells and just
  // do it for the newly added frames, but we need to add these frames to the
  // cell map before we reflow them
  tableFrame->InvalidateFirstPassCache();

  // Because the number of columns may have changed invalidate the column
  // cache. Note that this has the side effect of recomputing the column
  // widths, so we don't need to call InvalidateColumnWidths()
  tableFrame->InvalidateColumnCache();

  // Generate a reflow command so we reflow the table itself. This will
  // do a pass-1 reflow of all the rows including any rows we just added
  AddTableDirtyReflowCommand(aPresContext, aPresShell, tableFrame);
  return NS_OK;
}

NS_IMETHODIMP
nsTableRowGroupFrame::RemoveFrame(nsIPresContext& aPresContext,
                                  nsIPresShell&   aPresShell,
                                  nsIAtom*        aListName,
                                  nsIFrame*       aOldFrame)
{
  const nsStyleDisplay *display;
  aOldFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)display));

  // Remove the frame and destroy it
  if (mFrames.DestroyFrame(aPresContext, aOldFrame)) {
    if ((NS_STYLE_DISPLAY_TABLE_ROW == display->mDisplay) ||
        (NS_STYLE_DISPLAY_TABLE_ROW_GROUP == display->mDisplay)) {
      // Get the table frame
      nsTableFrame* tableFrame = nsnull;
      nsTableFrame::GetTableFrame(this, tableFrame);

      // We need to rebuild the cell map, because currently we can't incrementally
      // remove rows
      tableFrame->InvalidateCellMap();
      
      // Because the number of columns may have changed invalidate the column
      // cache. Note that this has the side effect of recomputing the column
      // widths, so we don't need to call InvalidateColumnWidths()
      tableFrame->InvalidateColumnCache();

      // Because we haven't added any new frames we don't need to do a pass1
      // reflow. Just generate a reflow command so we reflow the table itself
      AddTableDirtyReflowCommand(aPresContext, aPresShell, tableFrame);
    }
  }

  return NS_OK;
}

NS_METHOD nsTableRowGroupFrame::IR_TargetIsMe(nsIPresContext&      aPresContext,
                                              nsHTMLReflowMetrics& aDesiredSize,
                                              RowGroupReflowState& aReflowState,
                                              nsReflowStatus&      aStatus)
{
  nsresult rv = NS_FRAME_COMPLETE;
  nsIReflowCommand::ReflowType type;
  aReflowState.reflowState.reflowCommand->GetType(type);
  nsIFrame *objectFrame;
  aReflowState.reflowState.reflowCommand->GetChildFrame(objectFrame); 
  const nsStyleDisplay *childDisplay=nsnull;
  if (nsnull!=objectFrame)
    objectFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
  switch (type)
  {
  case nsIReflowCommand::ReflowDirty:
    // Reflow the dirty child frames. Typically this is newly added frames.
    // XXX What we really should do is do a pass-1 reflow of newly added
    // frames (only if necessary, i.e., the table isn't fixed layout), then
    // see if column widtsh changed and decide whether to do the pass-2 reflow
    // of just the dirty rows or have the table rebalance column widths and
    // do a pass-2 reflow of all rows
    rv = ReflowMappedChildren(aPresContext, aDesiredSize, aReflowState, aStatus,
                              nsnull, aReflowState.reflowState.reason, PR_TRUE, PR_TRUE);

    // If any column widths have to change due to this, rebalance column widths.
    // XXX need to calculate this, but for now just do it
    aReflowState.tableFrame->InvalidateColumnWidths();  
    break;

  case nsIReflowCommand::StyleChanged :
    rv = IR_StyleChanged(aPresContext, aDesiredSize, aReflowState, aStatus);
    break;

  case nsIReflowCommand::ContentChanged :
    NS_ASSERTION(PR_FALSE, "illegal reflow type: ContentChanged");
    rv = NS_ERROR_ILLEGAL_VALUE;
    break;
  
  default:
    NS_NOTYETIMPLEMENTED("unexpected reflow command type");
    rv = NS_ERROR_NOT_IMPLEMENTED;
    break;
  }

  // XXX If we have a next-in-flow, then we're not complete
  if (mNextInFlow) {
    aStatus = NS_FRAME_NOT_COMPLETE;
  }
  return rv;
}

NS_METHOD nsTableRowGroupFrame::DidAppendRow(nsTableRowFrame *aRowFrame)
{
  nsresult rv=NS_OK;
  /* need to make space in the cell map.  Remeber that row spans can't cross row groups
     once the space is made, tell the row to initizalize its children.  
     it will automatically find the row to initialize into.
     but this is tough because a cell in aInsertedFrame could have a rowspan
     which must be respected if a subsequent row is appended.
  */
  rv = aRowFrame->InitChildren();
  return rv;
}

// support method that tells us if there are any rows in the table after our rows
// returns PR_TRUE if there are no rows after ours
PRBool nsTableRowGroupFrame::NoRowsFollow()
{
  // XXX This method doesn't play well with the tree widget.
  PRBool result = PR_TRUE;
  nsIFrame *nextSib=nsnull;
  GetNextSibling(&nextSib);
  while (nsnull!=nextSib)
  {
    const nsStyleDisplay *sibDisplay;
    nextSib->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)sibDisplay));
    if ((NS_STYLE_DISPLAY_TABLE_HEADER_GROUP == sibDisplay->mDisplay) ||
        (NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP == sibDisplay->mDisplay) ||
        (NS_STYLE_DISPLAY_TABLE_ROW_GROUP    == sibDisplay->mDisplay))
    {
      nsIFrame *childFrame=nsnull;
      nextSib->FirstChild(nsnull, &childFrame);
      while (nsnull!=childFrame)
      {
        const nsStyleDisplay *childDisplay;
        childFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)childDisplay));
        if (NS_STYLE_DISPLAY_TABLE_ROW == childDisplay->mDisplay)
        { // found a row 
          result = PR_FALSE;
          break;
        }
        childFrame->GetNextSibling(&childFrame);
      }
    }
    nextSib->GetNextSibling(&nextSib);
  }
  return result;
}

NS_METHOD nsTableRowGroupFrame::GetHeightOfRows(nscoord& aResult)
{
  // the rows in rowGroupFrame need to be expanded by rowHeightDelta[i]
  // and the rowgroup itself needs to be expanded by SUM(row height deltas)
  nsIFrame * rowFrame=nsnull;
  nsresult rv = FirstChild(nsnull, &rowFrame);
  while ((NS_SUCCEEDED(rv)) && (nsnull!=rowFrame))
  {
    const nsStyleDisplay *rowDisplay;
    rowFrame->GetStyleData(eStyleStruct_Display, ((const nsStyleStruct *&)rowDisplay));
    if (NS_STYLE_DISPLAY_TABLE_ROW == rowDisplay->mDisplay)
    { 
      nsRect rowRect;
      rowFrame->GetRect(rowRect);
      aResult += rowRect.height;
    }
    else if (NS_STYLE_DISPLAY_TABLE_ROW_GROUP == rowDisplay->mDisplay)
    {
      ((nsTableRowGroupFrame*)rowFrame)->GetHeightOfRows(aResult);
    }
    GetNextFrame(rowFrame, &rowFrame);
  }
  return NS_OK;
}

// Recovers the reflow state to what it should be if aKidFrame is about
// to be reflowed. Restores the following:
// - availSize
// - y
// - firstRow
nsresult
nsTableRowGroupFrame::RecoverState(RowGroupReflowState& aReflowState,
                                   nsIFrame*            aKidFrame,
                                   nsSize*              aMaxElementSize)
{
  // Walk the list of children looking for aKidFrame
  for (nsIFrame* frame = mFrames.FirstChild(); frame; frame->GetNextSibling(&frame)) {
    if (frame == aKidFrame) {
      break;
    }

    // Update the running y-offset
    nsSize  kidSize;
    frame->GetSize(kidSize);
    aReflowState.y += kidSize.height;

    // If our height is constrained then update the available height
    if (PR_FALSE == aReflowState.unconstrainedHeight) {
      aReflowState.availSize.height -= kidSize.height;
    }

    // Update the maximum element size
    if (aMaxElementSize) {
      // Get the row frame's cached max element size
      nsSize kidMaxElementSize;
      ((nsTableRowFrame*)frame)->GetMaxElementSize(kidMaxElementSize);
    
      if (aReflowState.firstRow) {
        aMaxElementSize->width = kidMaxElementSize.width;
        aMaxElementSize->height = kidMaxElementSize.height;
      } else {
        aMaxElementSize->width = PR_MAX(aMaxElementSize->width, kidMaxElementSize.width);
      }
    }

    aReflowState.firstRow = PR_FALSE;
  }

  return NS_OK;
}

PRBool
nsTableRowGroupFrame::IsSimpleRowFrame(nsTableFrame* aTableFrame,
                                       nsIFrame*     aFrame)
{
  // Make sure it's a row frame and not a row group frame
  nsCOMPtr<nsIAtom>  frameType;

  aFrame->GetFrameType(getter_AddRefs(frameType));
  if (frameType.get() == nsLayoutAtoms::tableRowFrame) {
    PRInt32 rowIndex = ((nsTableRowFrame*)aFrame)->GetRowIndex();
    
    // It's a simple row frame if there are no cells that span into or
    // across the row
    if (!aTableFrame->RowIsSpannedInto(rowIndex) &&
        !aTableFrame->RowHasSpanningCells(rowIndex)) {
      return PR_TRUE;
    }
  }

  return PR_FALSE;
}

NS_METHOD nsTableRowGroupFrame::IR_TargetIsChild(nsIPresContext&      aPresContext,
                                                 nsHTMLReflowMetrics& aDesiredSize,
                                                 RowGroupReflowState& aReflowState,
                                                 nsReflowStatus&      aStatus,
                                                 nsIFrame *           aNextFrame)

{
  nsresult rv;
  // Recover the state as if aNextFrame is about to be reflowed
  RecoverState(aReflowState, aNextFrame, aDesiredSize.maxElementSize);

  // Remember the old rect
  nsRect  oldKidRect;
  aNextFrame->GetRect(oldKidRect);

  // Pass along the reflow command
  nsHTMLReflowState   kidReflowState(aPresContext, aReflowState.reflowState,
                                     aNextFrame, aReflowState.availSize);
  nsSize              kidMaxElementSize;
  nsHTMLReflowMetrics desiredSize(aDesiredSize.maxElementSize ? &kidMaxElementSize : nsnull);

  rv = ReflowChild(aNextFrame, aPresContext, desiredSize, kidReflowState, aStatus);

  // Place the row frame
  nsRect  kidRect(0, aReflowState.y, desiredSize.width, desiredSize.height);
  PlaceChild(aPresContext, aReflowState, aNextFrame, kidRect,
             aDesiredSize.maxElementSize, kidMaxElementSize);

  // See if the table needs a reflow (e.g., if the column widths have
  // changed). If so, just return and don't bother adjusting the rows
  // that follow
  if (!aReflowState.tableFrame->NeedsReflow(aReflowState.reflowState)) {
    // If the row has no cells that span into or across the row, then we
    // don't have to call CalculateRowHeights() which is quite expensive
    if (IsSimpleRowFrame(aReflowState.tableFrame, aNextFrame)) {
      // XXX This optimization isn't ready to be enabled yet, because the
      // row frame code needs to change to size the cell frame and vertically
      // align it and either bitblt it into its new position or repaint
#if 0
      // See if the row changed height
      if (oldKidRect.height == desiredSize.height) {
        // We don't need to do any painting. The row frame has made sure that
        // the cell is properly positioned, and done any necessary repainting.
        // Just calculate our desired height
        nsIFrame* lastKidFrame = mFrames.LastChild();
        nsRect    lastKidRect;

        lastKidFrame->GetRect(lastKidRect);
        aDesiredSize.height = lastKidRect.YMost();

      } else {
#endif
        // Inform the row of its new height.
        ((nsTableRowFrame*)aNextFrame)->DidResize(aPresContext, aReflowState.reflowState);

        // Because other cells in the row may need to be be aligned differently,
        // repaint the entire row
        // XXX Improve this so the row knows it should bitblt (or repaint) those
        // cells that change position...
        Invalidate(kidRect);

        // Invalidate the area we're offseting. Note that we only repaint within
        // our existing frame bounds.
        // XXX It would be better to bitblt the row frames and not repaint,
        // but we don't have such a view manager function yet...
        if (kidRect.YMost() < mRect.height) {
          nsRect  dirtyRect(0, kidRect.YMost(),
                            mRect.width, mRect.height - kidRect.YMost());
          Invalidate(dirtyRect);
        }

        // Adjust the frames that follow
        AdjustSiblingsAfterReflow(aPresContext, aReflowState, aNextFrame,
                                  aDesiredSize.maxElementSize,
                                  desiredSize.height - oldKidRect.height);
        aDesiredSize.height = aReflowState.y;
#if 0
      }
#endif
    
    } else {
      // Adjust the frames that follow...
      AdjustSiblingsAfterReflow(aPresContext, aReflowState, aNextFrame,
                                aDesiredSize.maxElementSize,
                                desiredSize.height - oldKidRect.height);
  
      // Now recalculate the row heights
      CalculateRowHeights(aPresContext, aDesiredSize, aReflowState.reflowState);

      // Because we don't know what changed repaint everything.
      // XXX We should change CalculateRowHeights() to return the bounding
      // rect of what changed. Or whether anything moved or changed size...
      nsRect  dirtyRect(0, 0, mRect.width, mRect.height);
      Invalidate(dirtyRect);
    }
  }
  
  // Return our desired width
  aDesiredSize.width = aReflowState.reflowState.availableWidth;

  if (mNextInFlow) {
    aStatus = NS_FRAME_NOT_COMPLETE;
  }

  return rv;
}

NS_METHOD nsTableRowGroupFrame::IR_StyleChanged(nsIPresContext&      aPresContext,
                                                nsHTMLReflowMetrics& aDesiredSize,
                                                RowGroupReflowState& aReflowState,
                                                nsReflowStatus&      aStatus)
{
  nsresult rv = NS_OK;
  // we presume that all the easy optimizations were done in the nsHTMLStyleSheet before we were called here
  // XXX: we can optimize this when we know which style attribute changed
  aReflowState.tableFrame->InvalidateFirstPassCache();
  return rv;
}

NS_IMETHODIMP
nsTableRowGroupFrame::GetFrameType(nsIAtom** aType) const
{
  NS_PRECONDITION(nsnull != aType, "null OUT parameter pointer");
  *aType = nsLayoutAtoms::tableRowGroupFrame; 
  NS_ADDREF(*aType);
  return NS_OK;
}


/* ----- global methods ----- */

nsresult 
NS_NewTableRowGroupFrame(nsIFrame** aNewFrame)
{
  NS_PRECONDITION(aNewFrame, "null OUT ptr");
  if (nsnull == aNewFrame) {
    return NS_ERROR_NULL_POINTER;
  }
  nsTableRowGroupFrame* it = new nsTableRowGroupFrame;
  if (nsnull == it) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  *aNewFrame = it;
  return NS_OK;
}

NS_IMETHODIMP
nsTableRowGroupFrame::GetFrameName(nsString& aResult) const
{
  return MakeFrameName("TableRowGroup", aResult);
}


#ifdef DEBUG
NS_IMETHODIMP
nsTableRowGroupFrame::SizeOf(nsISizeOfHandler* aHandler, PRUint32* aResult) const
{
  if (!aResult) {
    return NS_ERROR_NULL_POINTER;
  }
  PRUint32 sum = sizeof(*this);
  *aResult = sum;
  return NS_OK;
}
#endif