// the computed bsize for the cell, which descendants use for percent bsize calculations
// it is the bsize (minus border, padding) of the cell's first in flow during its final
// reflow without an unconstrained bsize.
static nscoord
CalcUnpaginatedBSize(nsPresContext*     aPresContext,
                      nsTableCellFrame& aCellFrame,
                      nsTableFrame&     aTableFrame,
                      nscoord           aBlockDirBorderPadding)
{
  const nsTableCellFrame* firstCellInFlow =
    static_cast<nsTableCellFrame*>(aCellFrame.FirstInFlow());
  nsTableFrame* firstTableInFlow  =
    static_cast<nsTableFrame*>(aTableFrame.FirstInFlow());
  nsTableRowFrame* row =
    static_cast<nsTableRowFrame*>(firstCellInFlow->GetParent());
  nsTableRowGroupFrame* firstRGInFlow =
    static_cast<nsTableRowGroupFrame*>(row->GetParent());

  int32_t rowIndex;
  firstCellInFlow->GetRowIndex(rowIndex);
  int32_t rowSpan = aTableFrame.GetEffectiveRowSpan(*firstCellInFlow);

  nscoord computedBSize = firstTableInFlow->GetRowSpacing(rowIndex,
                                                          rowIndex + rowSpan - 1);
  computedBSize -= aBlockDirBorderPadding;
  int32_t rowX;
  for (row = firstRGInFlow->GetFirstRow(), rowX = 0; row; row = row->GetNextRow(), rowX++) {
    if (rowX > rowIndex + rowSpan - 1) {
      break;
    }
    else if (rowX >= rowIndex) {
      computedBSize += row->GetUnpaginatedBSize(aPresContext);
    }
  }
  return computedBSize;
}

// the computed height for the cell, which descendants use for percent height calculations
// it is the height (minus border, padding) of the cell's first in flow during its final
// reflow without an unconstrained height.
static nscoord
CalcUnpaginagedHeight(nsPresContext*        aPresContext,
                      nsTableCellFrame&     aCellFrame,
                      nsTableFrame&         aTableFrame,
                      nscoord               aVerticalBorderPadding)
{
  const nsTableCellFrame* firstCellInFlow   = (nsTableCellFrame*)aCellFrame.GetFirstInFlow();
  nsTableFrame*           firstTableInFlow  = (nsTableFrame*)aTableFrame.GetFirstInFlow();
  nsTableRowFrame*        row
    = static_cast<nsTableRowFrame*>(firstCellInFlow->GetParent());
  nsTableRowGroupFrame*   firstRGInFlow
    = static_cast<nsTableRowGroupFrame*>(row->GetParent());

  int32_t rowIndex;
  firstCellInFlow->GetRowIndex(rowIndex);
  int32_t rowSpan = aTableFrame.GetEffectiveRowSpan(*firstCellInFlow);
  nscoord cellSpacing = firstTableInFlow->GetCellSpacingX();

  nscoord computedHeight = ((rowSpan - 1) * cellSpacing) - aVerticalBorderPadding;
  int32_t rowX;
  for (row = firstRGInFlow->GetFirstRow(), rowX = 0; row; row = row->GetNextRow(), rowX++) {
    if (rowX > rowIndex + rowSpan - 1) {
      break;
    }
    else if (rowX >= rowIndex) {
      computedHeight += row->GetUnpaginatedHeight(aPresContext);
    }
  }
  return computedHeight;
}

nscoord
GetSpaceBetween(PRInt32       aPrevColIndex,
                PRInt32       aColIndex,
                PRInt32       aColSpan,
                nsTableFrame& aTableFrame,
                nscoord       aCellSpacingX,
                bool          aIsLeftToRight,
                bool          aCheckVisibility)
{
  nscoord space = 0;
  PRInt32 colX;
  if (aIsLeftToRight) {
    for (colX = aPrevColIndex + 1; aColIndex > colX; colX++) {
      bool isCollapsed = false;
      if (!aCheckVisibility) {
        space += aTableFrame.GetColumnWidth(colX);
      }
      else {
        nsTableColFrame* colFrame = aTableFrame.GetColFrame(colX);
        const nsStyleVisibility* colVis = colFrame->GetStyleVisibility();
        bool collapseCol = (NS_STYLE_VISIBILITY_COLLAPSE == colVis->mVisible);
        nsIFrame* cgFrame = colFrame->GetParent();
        const nsStyleVisibility* groupVis = cgFrame->GetStyleVisibility();
        bool collapseGroup = (NS_STYLE_VISIBILITY_COLLAPSE ==
                                groupVis->mVisible);
        isCollapsed = collapseCol || collapseGroup;
        if (!isCollapsed)
          space += aTableFrame.GetColumnWidth(colX);
      }
      if (!isCollapsed && aTableFrame.ColumnHasCellSpacingBefore(colX)) {
        space += aCellSpacingX;
      }
    }
  } 
  else {
    PRInt32 lastCol = aColIndex + aColSpan - 1;
    for (colX = aPrevColIndex - 1; colX > lastCol; colX--) {
      bool isCollapsed = false;
      if (!aCheckVisibility) {
        space += aTableFrame.GetColumnWidth(colX);
      }
      else {
        nsTableColFrame* colFrame = aTableFrame.GetColFrame(colX);
        const nsStyleVisibility* colVis = colFrame->GetStyleVisibility();
        bool collapseCol = (NS_STYLE_VISIBILITY_COLLAPSE == colVis->mVisible);
        nsIFrame* cgFrame = colFrame->GetParent();
        const nsStyleVisibility* groupVis = cgFrame->GetStyleVisibility();
        bool collapseGroup = (NS_STYLE_VISIBILITY_COLLAPSE ==
                                groupVis->mVisible);
        isCollapsed = collapseCol || collapseGroup;
        if (!isCollapsed)
          space += aTableFrame.GetColumnWidth(colX);
      }
      if (!isCollapsed && aTableFrame.ColumnHasCellSpacingBefore(colX)) {
        space += aCellSpacingX;
      }
    }
  }
  return space;
}

nscoord 
GetHeightOfRowsSpannedBelowFirst(nsTableCellFrame& aTableCellFrame,
                                 nsTableFrame&     aTableFrame)
{
  nscoord height = 0;
  nscoord cellSpacingY = aTableFrame.GetCellSpacingY();
  PRInt32 rowSpan = aTableFrame.GetEffectiveRowSpan(aTableCellFrame);
  // add in height of rows spanned beyond the 1st one
  nsIFrame* nextRow = aTableCellFrame.GetParent()->GetNextSibling();
  for (PRInt32 rowX = 1; ((rowX < rowSpan) && nextRow);) {
    if (nsGkAtoms::tableRowFrame == nextRow->GetType()) {
      height += nextRow->GetSize().height;
      rowX++;
    }
    height += cellSpacingY;
    nextRow = nextRow->GetNextSibling();
  }
  return height;
}

// Calculates the available width for the table cell based on the known
// column widths taking into account column spans and column spacing
static nscoord
CalcAvailWidth(nsTableFrame&     aTableFrame,
               nsTableCellFrame& aCellFrame,
               nscoord           aCellSpacingX)
{
  nscoord cellAvailWidth = 0;
  PRInt32 colIndex;
  aCellFrame.GetColIndex(colIndex);
  PRInt32 colspan = aTableFrame.GetEffectiveColSpan(aCellFrame);
  NS_ASSERTION(colspan > 0, "effective colspan should be positive");

  for (PRInt32 spanX = 0; spanX < colspan; spanX++) {
    cellAvailWidth += aTableFrame.GetColumnWidth(colIndex + spanX);
    if (spanX > 0 &&
        aTableFrame.ColumnHasCellSpacingBefore(colIndex + spanX)) {
      cellAvailWidth += aCellSpacingX;
    }
  }
  return cellAvailWidth;
}

nsresult
nsTableRowFrame::ReflowChildren(nsPresContext*          aPresContext,
                                nsHTMLReflowMetrics&     aDesiredSize,
                                const nsHTMLReflowState& aReflowState,
                                nsTableFrame&            aTableFrame,
                                nsReflowStatus&          aStatus)
{
  aStatus = NS_FRAME_COMPLETE;

  // XXXldb Should we be checking constrained height instead?
  const bool isPaginated = aPresContext->IsPaginated();
  const bool borderCollapse = aTableFrame.IsBorderCollapse();
  nsresult rv = NS_OK;
  nscoord cellSpacingX = aTableFrame.GetCellSpacingX();
  PRInt32 cellColSpan = 1;  // must be defined here so it's set properly for non-cell kids
  
  nsTableIterator iter(*this);
  // remember the col index of the previous cell to handle rowspans into this row
  PRInt32 firstPrevColIndex = (iter.IsLeftToRight()) ? -1 : aTableFrame.GetColCount();
  PRInt32 prevColIndex  = firstPrevColIndex;
  nscoord x = 0; // running total of children x offset

  // This computes the max of all cell heights
  nscoord cellMaxHeight = 0;

  // Reflow each of our existing cell frames
  for (nsIFrame* kidFrame = iter.First(); kidFrame; kidFrame = iter.Next()) {
    nsTableCellFrame *cellFrame = do_QueryFrame(kidFrame);
    if (!cellFrame) {
      // XXXldb nsCSSFrameConstructor needs to enforce this!
      NS_NOTREACHED("yikes, a non-row child");

      // it's an unknown frame type, give it a generic reflow and ignore the results
      nsTableCellReflowState kidReflowState(aPresContext, aReflowState,
                                            kidFrame, nsSize(0,0), false);
      InitChildReflowState(*aPresContext, nsSize(0,0), false, kidReflowState);
      nsHTMLReflowMetrics desiredSize;
      nsReflowStatus  status;
      ReflowChild(kidFrame, aPresContext, desiredSize, kidReflowState, 0, 0, 0, status);
      kidFrame->DidReflow(aPresContext, nullptr, NS_FRAME_REFLOW_FINISHED);

      continue;
    }

    // See if we should only reflow the dirty child frames
    bool doReflowChild = true;
    if (!aReflowState.ShouldReflowAllKids() &&
        !aTableFrame.IsGeometryDirty() &&
        !NS_SUBTREE_DIRTY(kidFrame)) {
      if (!aReflowState.mFlags.mSpecialHeightReflow)
        doReflowChild = false;
    }
    else if ((NS_UNCONSTRAINEDSIZE != aReflowState.availableHeight)) {
      // We don't reflow a rowspan >1 cell here with a constrained height. 
      // That happens in nsTableRowGroupFrame::SplitSpanningCells.
      if (aTableFrame.GetEffectiveRowSpan(*cellFrame) > 1) {
        doReflowChild = false;
      }
    }
    if (aReflowState.mFlags.mSpecialHeightReflow) {
      if (!isPaginated && !(cellFrame->GetStateBits() &
                            NS_FRAME_CONTAINS_RELATIVE_HEIGHT)) {
        continue;
      }
    }

    PRInt32 cellColIndex;
    cellFrame->GetColIndex(cellColIndex);
    cellColSpan = aTableFrame.GetEffectiveColSpan(*cellFrame);

    // If the adjacent cell is in a prior row (because of a rowspan) add in the space
    if ((iter.IsLeftToRight() && (prevColIndex != (cellColIndex - 1))) ||
        (!iter.IsLeftToRight() && (prevColIndex != cellColIndex + cellColSpan))) {
      x += GetSpaceBetween(prevColIndex, cellColIndex, cellColSpan, aTableFrame, 
                           cellSpacingX, iter.IsLeftToRight(), false);
    }

    // remember the rightmost (ltr) or leftmost (rtl) column this cell spans into
    prevColIndex = (iter.IsLeftToRight()) ? cellColIndex + (cellColSpan - 1) : cellColIndex;

    // Reflow the child frame
    nsRect kidRect = kidFrame->GetRect();
    nsRect kidVisualOverflow = kidFrame->GetVisualOverflowRect();
    bool firstReflow =
      (kidFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW) != 0;

    if (doReflowChild) {
      // Calculate the available width for the table cell using the known column widths
      nscoord availCellWidth =
        CalcAvailWidth(aTableFrame, *cellFrame, cellSpacingX);

      nsHTMLReflowMetrics desiredSize;

      // If the avail width is not the same as last time we reflowed the cell or
      // the cell wants to be bigger than what was available last time or
      // it is a style change reflow or we are printing, then we must reflow the
      // cell. Otherwise we can skip the reflow.
      // XXXldb Why is this condition distinct from doReflowChild above?
      nsSize cellDesiredSize = cellFrame->GetDesiredSize();
      if ((availCellWidth != cellFrame->GetPriorAvailWidth())       ||
//.........这里部分代码省略.........