/*
 * Copyright (C) 1997 Martin Jones (mjones@kde.org)
 *           (C) 1997 Torben Weis (weis@kde.org)
 *           (C) 1998 Waldo Bastian (bastian@kde.org)
 *           (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 * Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "core/layout/LayoutTableSection.h"

#include "core/layout/HitTestResult.h"
#include "core/layout/LayoutAnalyzer.h"
#include "core/layout/LayoutTableCell.h"
#include "core/layout/LayoutTableCol.h"
#include "core/layout/LayoutTableRow.h"
#include "core/layout/LayoutView.h"
#include "core/layout/SubtreeLayoutScope.h"
#include "core/paint/TableSectionPainter.h"
#include "wtf/HashSet.h"
#include <algorithm>
#include <limits>

namespace blink {

using namespace HTMLNames;

// This variable is used to balance the memory consumption vs the paint invalidation time on big tables.
static unsigned gMinTableSizeToUseFastPaintPathWithOverflowingCell = 75 * 75;

static inline void setRowLogicalHeightToRowStyleLogicalHeight(LayoutTableSection::RowStruct& row)
{
    ASSERT(row.rowLayoutObject);
    row.logicalHeight = row.rowLayoutObject->style()->logicalHeight();
}

static inline void updateLogicalHeightForCell(LayoutTableSection::RowStruct&
row, const LayoutTableCell* cell)
{
    // We ignore height settings on rowspan cells.
    if (cell->rowSpan() != 1)
        return;

    Length logicalHeight = cell->style()->logicalHeight();
    if (logicalHeight.isPositive()) {
        Length cRowLogicalHeight = row.logicalHeight;
        switch (logicalHeight.type()) {
        case Percent:
            // TODO(alancutter): Make this work correctly for calc lengths.
            if (!(cRowLogicalHeight.hasPercent())
                || (cRowLogicalHeight.hasPercent() && cRowLogicalHeight.percent() < logicalHeight.percent()))
                row.logicalHeight = logicalHeight;
            break;
        case Fixed:
            if (cRowLogicalHeight.type() < Percent
                || (cRowLogicalHeight.isFixed() && cRowLogicalHeight.value() < logicalHeight.value()))
                row.logicalHeight = logicalHeight;
            break;
        default:
            break;
        }
    }
}

void CellSpan::ensureConsistency(const unsigned maximumSpanSize)
{
    static_assert(std::is_same<decltype(m_start), unsigned>::value, "Asserts below assume m_start is unsigned");
    static_assert(std::is_same<decltype(m_end), unsigned>::value, "Asserts below assume m_end is unsigned");
    RELEASE_ASSERT(m_start <= maximumSpanSize);
    RELEASE_ASSERT(m_end <= maximumSpanSize);
    RELEASE_ASSERT(m_start <= m_end);
}

LayoutTableSection::LayoutTableSection(Element* element)
    : LayoutBox(element)
    , m_cCol(0)
    , m_cRow(0)
    , m_outerBorderStart(0)
    , m_outerBorderEnd(0)
    , m_outerBorderBefore(0)
    , m_outerBorderAfter(0)
    , m_needsCellRecalc(false)
    , m_forceSlowPaintPathWithOverflowingCell(false)
    , m_hasMultipleCellLevels(false)
{
    // init LayoutObject attributes
    setInline(false); // our object is not Inline
}

LayoutTableSection::~LayoutTableSection()
{
}

void LayoutTableSection::styleDidChange(StyleDifference diff, const ComputedStyle* oldStyle)
{
    LayoutBox::styleDidChange(diff, oldStyle);
    propagateStyleToAnonymousChildren();

    // If border was changed, notify table.
    LayoutTable* table = this->table();
    if (table && !table->selfNeedsLayout() && !table->normalChildNeedsLayout() && oldStyle && oldStyle->border() != style()->border())
        table->invalidateCollapsedBorders();
}

void LayoutTableSection::willBeRemovedFromTree()
{
    LayoutBox::willBeRemovedFromTree();

    // Preventively invalidate our cells as we may be re-inserted into
    // a new table which would require us to rebuild our structure.
    setNeedsCellRecalc();
}

void LayoutTableSection::addChild(LayoutObject* child, LayoutObject* beforeChild)
{
    if (!child->isTableRow()) {
        LayoutObject* last = beforeChild;
        if (!last)
            last = lastRow();
        if (last && last->isAnonymous() && !last->isBeforeOrAfterContent()) {
            if (beforeChild == last)
                beforeChild = last->slowFirstChild();
            last->addChild(child, beforeChild);
            return;
        }

        if (beforeChild && !beforeChild->isAnonymous() && beforeChild->parent() == this) {
            LayoutObject* row = beforeChild->previousSibling();
            if (row && row->isTableRow() && row->isAnonymous()) {
                row->addChild(child);
                return;
            }
        }

        // If beforeChild is inside an anonymous cell/row, insert into the cell or into
        // the anonymous row containing it, if there is one.
        LayoutObject* lastBox = last;
        while (lastBox && lastBox->parent()->isAnonymous() && !lastBox->isTableRow())
            lastBox = lastBox->parent();
        if (lastBox && lastBox->isAnonymous() && !lastBox->isBeforeOrAfterContent()) {
            lastBox->addChild(child, beforeChild);
            return;
        }

        LayoutObject* row = LayoutTableRow::createAnonymousWithParent(this);
        addChild(row, beforeChild);
        row->addChild(child);
        return;
    }

    if (beforeChild)
        setNeedsCellRecalc();

    unsigned insertionRow = m_cRow;
    ++m_cRow;
    m_cCol = 0;

    ensureRows(m_cRow);

    LayoutTableRow* row = toLayoutTableRow(child);
    m_grid[insertionRow].rowLayoutObject = row;
    row->setRowIndex(insertionRow);

    if (!beforeChild)
        setRowLogicalHeightToRowStyleLogicalHeight(m_grid[insertionRow]);

    if (beforeChild && beforeChild->parent() != this)
        beforeChild = splitAnonymousBoxesAroundChild(beforeChild);

    ASSERT(!beforeChild || beforeChild->isTableRow());
    LayoutBox::addChild(child, beforeChild);
}

void LayoutTableSection::ensureRows(unsigned numRows)
{
    if (numRows <= m_grid.size())
        return;

    unsigned oldSize = m_grid.size();
    m_grid.grow(numRows);

    unsigned effectiveColumnCount = std::max(1u, table()->numEffectiveColumns());
    for (unsigned row = oldSize; row < m_grid.size(); ++row)
        m_grid[row].row.grow(effectiveColumnCount);
}

static inline void checkThatVectorIsDOMOrdered(const Vector<LayoutTableCell*, 1>& cells)
{
#ifndef NDEBUG
    // This function should be called on a non-empty vector.
    ASSERT(cells.size() > 0);

    const LayoutTableCell* previousCell = cells[0];
    for (size_t i = 1; i < cells.size(); ++i) {
        const LayoutTableCell* currentCell = cells[i];
        // The check assumes that all cells belong to the same row group.
        ASSERT(previousCell->section() == currentCell->section());

        // 2 overlapping cells can't be on the same row.
        ASSERT(currentCell->row() != previousCell->row());

        // Look backwards in the tree for the previousCell's row. If we are
        // DOM ordered, we should find it.
        const LayoutTableRow* row = currentCell->row();
        for (; row && row != previousCell->row(); row = row->previousRow()) { }
        ASSERT(row == previousCell->row());

        previousCell = currentCell;
    }
#endif // NDEBUG
}

void LayoutTableSection::addCell(LayoutTableCell* cell, LayoutTableRow* row)
{
    // We don't insert the cell if we need cell recalc as our internal columns' representation
    // will have drifted from the table's representation. Also recalcCells will call addCell
    // at a later time after sync'ing our columns' with the table's.
    if (needsCellRecalc())
        return;

    unsigned rSpan = cell->rowSpan();
    unsigned cSpan = cell->colSpan();
    const Vector<LayoutTable::ColumnStruct>& columns = table()->effectiveColumns();
    unsigned nCols = columns.size();
    unsigned insertionRow = row->rowIndex();

    // ### mozilla still seems to do the old HTML way, even for strict DTD
    // (see the annotation on table cell layouting in the CSS specs and the testcase below:
    // <TABLE border>
    // <TR><TD>1 <TD rowspan="2">2 <TD>3 <TD>4
    // <TR><TD colspan="2">5
    // </TABLE>
    while (m_cCol < nCols && (cellAt(insertionRow, m_cCol).hasCells() || cellAt(insertionRow, m_cCol).inColSpan))
        m_cCol++;

    updateLogicalHeightForCell(m_grid[insertionRow], cell);

    ensureRows(insertionRow + rSpan);

    m_grid[insertionRow].rowLayoutObject = row;

    unsigned col = m_cCol;
    // tell the cell where it is
    bool inColSpan = false;
    while (cSpan) {
        unsigned currentSpan;
        if (m_cCol >= nCols) {
            table()->appendEffectiveColumn(cSpan);
            currentSpan = cSpan;
        } else {
            if (cSpan < columns[m_cCol].span)
                table()->splitEffectiveColumn(m_cCol, cSpan);
            currentSpan = columns[m_cCol].span;
        }
        for (unsigned r = 0; r < rSpan; r++) {
            CellStruct& c = cellAt(insertionRow + r, m_cCol);
            ASSERT(cell);
            c.cells.append(cell);
            checkThatVectorIsDOMOrdered(c.cells);
            // If cells overlap then we take the slow path for painting.
            if (c.cells.size() > 1)
                m_hasMultipleCellLevels = true;
            if (inColSpan)
                c.inColSpan = true;
        }
        m_cCol++;
        cSpan -= currentSpan;
        inColSpan = true;
    }
    cell->setAbsoluteColumnIndex(table()->effectiveColumnToAbsoluteColumn(col));
}

bool LayoutTableSection::rowHasOnlySpanningCells(unsigned row)
{
    unsigned totalCols = m_grid[row].row.size();

    if (!totalCols)
        return false;

    for (unsigned col = 0; col < totalCols; col++) {
        const CellStruct& rowSpanCell = cellAt(row, col);

        // Empty cell is not a valid cell so it is not a rowspan cell.
        if (rowSpanCell.cells.isEmpty())
            return false;

        if (rowSpanCell.cells[0]->rowSpan() == 1)
            return false;
    }

    return true;
}

void LayoutTableSection::populateSpanningRowsHeightFromCell(LayoutTableCell* cell, struct SpanningRowsHeight& spanningRowsHeight)
{
    const unsigned rowSpan = cell->rowSpan();
    const unsigned rowIndex = cell->rowIndex();

    spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing = cell->logicalHeightForRowSizing();

    spanningRowsHeight.rowHeight.resize(rowSpan);
    spanningRowsHeight.totalRowsHeight = 0;
    for (unsigned row = 0; row < rowSpan; row++) {
        unsigned actualRow = row + rowIndex;

        spanningRowsHeight.rowHeight[row] = m_rowPos[actualRow + 1] - m_rowPos[actualRow] - borderSpacingForRow(actualRow);
        if (!spanningRowsHeight.rowHeight[row])
            spanningRowsHeight.isAnyRowWithOnlySpanningCells |= rowHasOnlySpanningCells(actualRow);

        spanningRowsHeight.totalRowsHeight += spanningRowsHeight.rowHeight[row];
        spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing -= borderSpacingForRow(actualRow);
    }
    // We don't span the following row so its border-spacing (if any) should be included.
    spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing += borderSpacingForRow(rowIndex + rowSpan - 1);
}

void LayoutTableSection::distributeExtraRowSpanHeightToPercentRows(LayoutTableCell* cell, float totalPercent, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
{
    if (!extraRowSpanningHeight || !totalPercent)
        return;

    const unsigned rowSpan = cell->rowSpan();
    const unsigned rowIndex = cell->rowIndex();
    float percent = std::min(totalPercent, 100.0f);
    const int tableHeight = m_rowPos[m_grid.size()] + extraRowSpanningHeight;

    // Our algorithm matches Firefox. Extra spanning height would be distributed Only in first percent height rows
    // those total percent is 100. Other percent rows would be uneffected even extra spanning height is remain.
    int accumulatedPositionIncrease = 0;
    for (unsigned row = rowIndex; row < (rowIndex + rowSpan); row++) {
        if (percent > 0 && extraRowSpanningHeight > 0) {
            // TODO(alancutter): Make this work correctly for calc lengths.
            if (m_grid[row].logicalHeight.hasPercent()) {
                int toAdd = (tableHeight * std::min(m_grid[row].logicalHeight.percent(), percent) / 100) - rowsHeight[row - rowIndex];

                toAdd = std::max(std::min(toAdd, extraRowSpanningHeight), 0);
                accumulatedPositionIncrease += toAdd;
                extraRowSpanningHeight -= toAdd;
                percent -= m_grid[row].logicalHeight.percent();
            }
        }
        m_rowPos[row + 1] += accumulatedPositionIncrease;
    }
}


static void updatePositionIncreasedWithRowHeight(int extraHeight, float rowHeight, float totalHeight, int& accumulatedPositionIncrease, double& remainder)
{
    // Without the cast we lose enough precision to cause heights to miss pixels
    // (and trigger asserts) in some layout tests.
    double proportionalPositionIncrease = remainder + (extraHeight * double(rowHeight)) / totalHeight;
    // The epsilon is to push any values that are close to a whole number but aren't due to floating point imprecision.
    // The epsilons are not accumulated, any that aren't necessary are lost in the cast to int.
    int positionIncreaseInt = proportionalPositionIncrease + 0.000001;
    accumulatedPositionIncrease += positionIncreaseInt;
    remainder = proportionalPositionIncrease - positionIncreaseInt;
}

// This is mainly used to distribute whole extra rowspanning height in percent rows when all spanning rows are
// percent rows.
// Distributing whole extra rowspanning height in percent rows based on the ratios of percent because this method works
// same as percent distribution when only percent rows are present and percent is 100. Also works perfectly fine when
// percent is not equal to 100.
void LayoutTableSection::distributeWholeExtraRowSpanHeightToPercentRows(LayoutTableCell* cell, float totalPercent, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
{
    if (!extraRowSpanningHeight || !totalPercent)
        return;

    const unsigned rowSpan = cell->rowSpan();
    const unsigned rowIndex = cell->rowIndex();
    double remainder = 0;

    int accumulatedPositionIncrease = 0;
    for (unsigned row = rowIndex; row < (rowIndex + rowSpan); row++) {
        // TODO(alancutter): Make this work correctly for calc lengths.
        if (m_grid[row].logicalHeight.hasPercent()) {
            updatePositionIncreasedWithRowHeight(extraRowSpanningHeight, m_grid[row].logicalHeight.percent(), totalPercent, accumulatedPositionIncrease, remainder);
        }
        m_rowPos[row + 1] += accumulatedPositionIncrease;
    }

    DCHECK(!round(remainder)) << "remainder was " << remainder;

    extraRowSpanningHeight -= accumulatedPositionIncrease;
}

void LayoutTableSection::distributeExtraRowSpanHeightToAutoRows(LayoutTableCell* cell, int totalAutoRowsHeight, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
{
    if (!extraRowSpanningHeight || !totalAutoRowsHeight)
        return;

    const unsigned rowSpan = cell->rowSpan();
    const unsigned rowIndex = cell->rowIndex();
    int accumulatedPositionIncrease = 0;
    double remainder = 0;

    // Aspect ratios of auto rows should not change otherwise table may look different than user expected.
    // So extra height distributed in auto spanning rows based on their weight in spanning cell.
    for (unsigned row = rowIndex; row < (rowIndex + rowSpan); row++) {
        if (m_grid[row].logicalHeight.isAuto()) {
            updatePositionIncreasedWithRowHeight(extraRowSpanningHeight, rowsHeight[row - rowIndex], totalAutoRowsHeight, accumulatedPositionIncrease, remainder);
        }
        m_rowPos[row + 1] += accumulatedPositionIncrease;
    }

    DCHECK(!round(remainder)) << "remainder was " << remainder;

    extraRowSpanningHeight -= accumulatedPositionIncrease;
}

void LayoutTableSection::distributeExtraRowSpanHeightToRemainingRows(LayoutTableCell* cell, int totalRemainingRowsHeight, int& extraRowSpanningHeight, Vector<int>& rowsHeight)
{
    if (!extraRowSpanningHeight || !totalRemainingRowsHeight)
        return;

    const unsigned rowSpan = cell->rowSpan();
    const unsigned rowIndex = cell->rowIndex();
    int accumulatedPositionIncrease = 0;
    double remainder = 0;

    // Aspect ratios of the rows should not change otherwise table may look different than user expected.
    // So extra height distribution in remaining spanning rows based on their weight in spanning cell.
    for (unsigned row = rowIndex; row < (rowIndex + rowSpan); row++) {
        if (!m_grid[row].logicalHeight.hasPercent()) {
            updatePositionIncreasedWithRowHeight(extraRowSpanningHeight, rowsHeight[row - rowIndex], totalRemainingRowsHeight, accumulatedPositionIncrease, remainder);
        }
        m_rowPos[row + 1] += accumulatedPositionIncrease;
    }

    DCHECK(!round(remainder)) << "remainder was " << remainder;

    extraRowSpanningHeight -= accumulatedPositionIncrease;
}

static bool cellIsFullyIncludedInOtherCell(const LayoutTableCell* cell1, const LayoutTableCell* cell2)
{
    return (cell1->rowIndex() >= cell2->rowIndex() && (cell1->rowIndex() + cell1->rowSpan()) <= (cell2->rowIndex() + cell2->rowSpan()));
}

// To avoid unneeded extra height distributions, we apply the following sorting algorithm:
static bool compareRowSpanCellsInHeightDistributionOrder(const LayoutTableCell* cell1, const LayoutTableCell* cell2)
{
    // Sorting bigger height cell first if cells are at same index with same span because we will skip smaller
    // height cell to distribute it's extra height.
    if (cell1->rowIndex() == cell2->rowIndex() && cell1->rowSpan() == cell2->rowSpan())
        return (cell1->logicalHeightForRowSizing() > cell2->logicalHeightForRowSizing());
    // Sorting inner most cell first because if inner spanning cell'e extra height is distributed then outer
    // spanning cell's extra height will adjust accordingly. In reverse order, there is more chances that outer
    // spanning cell's height will exceed than defined by user.
    if (cellIsFullyIncludedInOtherCell(cell1, cell2))
        return true;
    // Sorting lower row index first because first we need to apply the extra height of spanning cell which
    // comes first in the table so lower rows's position would increment in sequence.
    if (!cellIsFullyIncludedInOtherCell(cell2, cell1))
        return (cell1->rowIndex() < cell2->rowIndex());

    return false;
}

unsigned LayoutTableSection::calcRowHeightHavingOnlySpanningCells(unsigned row, int& accumulatedCellPositionIncrease, unsigned rowToApplyExtraHeight, unsigned& extraTableHeightToPropgate, Vector<int>& rowsCountWithOnlySpanningCells)
{
    ASSERT(rowHasOnlySpanningCells(row));

    unsigned totalCols = m_grid[row].row.size();

    if (!totalCols)
        return 0;

    unsigned rowHeight = 0;

    for (unsigned col = 0; col < totalCols; col++) {
        const CellStruct& rowSpanCell = cellAt(row, col);

        if (!rowSpanCell.cells.size())
            continue;

        LayoutTableCell* cell = rowSpanCell.cells[0];

        if (cell->rowSpan() < 2)
            continue;

        const unsigned cellRowIndex = cell->rowIndex();
        const unsigned cellRowSpan = cell->rowSpan();

        // As we are going from the top of the table to the bottom to calculate the row
        // heights for rows that only contain spanning cells and all previous rows are
        // processed we only need to find the number of rows with spanning cells from the
        // current cell to the end of the current cells spanning height.
        unsigned startRowForSpanningCellCount = std::max(cellRowIndex, row);
        unsigned endRow = cellRowIndex + cellRowSpan;
        unsigned spanningCellsRowsCountHavingZeroHeight = rowsCountWithOnlySpanningCells[endRow - 1];

        if (startRowForSpanningCellCount)
            spanningCellsRowsCountHavingZeroHeight -= rowsCountWithOnlySpanningCells[startRowForSpanningCellCount - 1];

        int totalRowspanCellHeight = (m_rowPos[endRow] - m_rowPos[cellRowIndex]) - borderSpacingForRow(endRow - 1);

        totalRowspanCellHeight += accumulatedCellPositionIncrease;
        if (rowToApplyExtraHeight >= cellRowIndex && rowToApplyExtraHeight < endRow)
            totalRowspanCellHeight += extraTableHeightToPropgate;

        if (totalRowspanCellHeight < cell->logicalHeightForRowSizing()) {
            unsigned extraHeightRequired = cell->logicalHeightForRowSizing() - totalRowspanCellHeight;

            rowHeight = std::max(rowHeight, extraHeightRequired / spanningCellsRowsCountHavingZeroHeight);
        }
    }

    return rowHeight;
}

void LayoutTableSection::updateRowsHeightHavingOnlySpanningCells(LayoutTableCell* cell, struct SpanningRowsHeight& spanningRowsHeight, unsigned& extraHeightToPropagate, Vector<int>& rowsCountWithOnlySpanningCells)
{
    ASSERT(spanningRowsHeight.rowHeight.size());

    int accumulatedPositionIncrease = 0;
    const unsigned rowSpan = cell->rowSpan();
    const unsigned rowIndex = cell->rowIndex();

    ASSERT_UNUSED(rowSpan, rowSpan == spanningRowsHeight.rowHeight.size());

    for (unsigned row = 0; row < spanningRowsHeight.rowHeight.size(); row++) {
        unsigned actualRow = row + rowIndex;
        if (!spanningRowsHeight.rowHeight[row] && rowHasOnlySpanningCells(actualRow)) {
            spanningRowsHeight.rowHeight[row] = calcRowHeightHavingOnlySpanningCells(actualRow, accumulatedPositionIncrease, rowIndex + rowSpan, extraHeightToPropagate, rowsCountWithOnlySpanningCells);
            accumulatedPositionIncrease += spanningRowsHeight.rowHeight[row];
        }
        m_rowPos[actualRow + 1] += accumulatedPositionIncrease;
    }

    spanningRowsHeight.totalRowsHeight += accumulatedPositionIncrease;
}

// Distribute rowSpan cell height in rows those comes in rowSpan cell based on the ratio of row's height if
// 1. RowSpan cell height is greater then the total height of rows in rowSpan cell
void LayoutTableSection::distributeRowSpanHeightToRows(SpanningLayoutTableCells& rowSpanCells)
{
    ASSERT(rowSpanCells.size());

    // 'rowSpanCells' list is already sorted based on the cells rowIndex in ascending order
    // Arrange row spanning cell in the order in which we need to process first.
    std::sort(rowSpanCells.begin(), rowSpanCells.end(), compareRowSpanCellsInHeightDistributionOrder);

    unsigned extraHeightToPropagate = 0;
    unsigned lastRowIndex = 0;
    unsigned lastRowSpan = 0;

    Vector<int> rowsCountWithOnlySpanningCells;

    // At this stage, Height of the rows are zero for the one containing only spanning cells.
    int count = 0;
    for (unsigned row = 0; row < m_grid.size(); row++) {
        if (rowHasOnlySpanningCells(row))
            count++;
        rowsCountWithOnlySpanningCells.append(count);
    }

    for (unsigned i = 0; i < rowSpanCells.size(); i++) {
        LayoutTableCell* cell = rowSpanCells[i];

        unsigned rowIndex = cell->rowIndex();

        unsigned rowSpan = cell->rowSpan();

        unsigned spanningCellEndIndex = rowIndex + rowSpan;
        unsigned lastSpanningCellEndIndex = lastRowIndex + lastRowSpan;

        // Only heightest spanning cell will distribute it's extra height in row if more then one spanning cells
        // present at same level.
        if (rowIndex == lastRowIndex && rowSpan == lastRowSpan)
            continue;

        int originalBeforePosition = m_rowPos[spanningCellEndIndex];

        // When 2 spanning cells are ending at same row index then while extra height distribution of first spanning
        // cell updates position of the last row so getting the original position of the last row in second spanning
        // cell need to reduce the height changed by first spanning cell.
        if (spanningCellEndIndex == lastSpanningCellEndIndex)
            originalBeforePosition -= extraHeightToPropagate;

        if (extraHeightToPropagate) {
            for (unsigned row = lastSpanningCellEndIndex + 1; row <= spanningCellEndIndex; row++)
                m_rowPos[row] += extraHeightToPropagate;
        }

        lastRowIndex = rowIndex;
        lastRowSpan = rowSpan;

        struct SpanningRowsHeight spanningRowsHeight;

        populateSpanningRowsHeightFromCell(cell, spanningRowsHeight);

        // Here we are handling only row(s) who have only rowspanning cells and do not have any empty cell.
        if (spanningRowsHeight.isAnyRowWithOnlySpanningCells)
            updateRowsHeightHavingOnlySpanningCells(cell, spanningRowsHeight, extraHeightToPropagate, rowsCountWithOnlySpanningCells);

        // This code handle row(s) that have rowspanning cell(s) and at least one empty cell.
        // Such rows are not handled below and end up having a height of 0. That would mean
        // content overlapping if one of their cells has any content. To avoid the problem, we
        // add all the remaining spanning cells' height to the last spanned row.
        // This means that we could grow a row past its 'height' or break percentage spreading
        // however this is better than overlapping content.
        // FIXME: Is there a better algorithm?
        if (!spanningRowsHeight.totalRowsHeight) {
            if (spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing)
                m_rowPos[spanningCellEndIndex] += spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing + borderSpacingForRow(spanningCellEndIndex - 1);

            extraHeightToPropagate = m_rowPos[spanningCellEndIndex] - originalBeforePosition;
            continue;
        }

        if (spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing <= spanningRowsHeight.totalRowsHeight) {
            extraHeightToPropagate = m_rowPos[rowIndex + rowSpan] - originalBeforePosition;
            continue;
        }

        // Below we are handling only row(s) who have at least one visible cell without rowspan value.
        float totalPercent = 0;
        int totalAutoRowsHeight = 0;
        int totalRemainingRowsHeight = spanningRowsHeight.totalRowsHeight;

        // FIXME: Inner spanning cell height should not change if it have fixed height when it's parent spanning cell
        // is distributing it's extra height in rows.

        // Calculate total percentage, total auto rows height and total rows height except percent rows.
        for (unsigned row = rowIndex; row < spanningCellEndIndex; row++) {
            // TODO(alancutter): Make this work correctly for calc lengths.
            if (m_grid[row].logicalHeight.hasPercent()) {
                totalPercent += m_grid[row].logicalHeight.percent();
                totalRemainingRowsHeight -= spanningRowsHeight.rowHeight[row - rowIndex];
            } else if (m_grid[row].logicalHeight.isAuto()) {
                totalAutoRowsHeight += spanningRowsHeight.rowHeight[row - rowIndex];
            }
        }

        int extraRowSpanningHeight = spanningRowsHeight.spanningCellHeightIgnoringBorderSpacing - spanningRowsHeight.totalRowsHeight;

        if (totalPercent < 100 && !totalAutoRowsHeight && !totalRemainingRowsHeight) {
            // Distributing whole extra rowspanning height in percent row when only non-percent rows height is 0.
            distributeWholeExtraRowSpanHeightToPercentRows(cell, totalPercent, extraRowSpanningHeight, spanningRowsHeight.rowHeight);
        } else {
            distributeExtraRowSpanHeightToPercentRows(cell, totalPercent, extraRowSpanningHeight, spanningRowsHeight.rowHeight);
            distributeExtraRowSpanHeightToAutoRows(cell, totalAutoRowsHeight, extraRowSpanningHeight, spanningRowsHeight.rowHeight);
            distributeExtraRowSpanHeightToRemainingRows(cell, totalRemainingRowsHeight, extraRowSpanningHeight, spanningRowsHeight.rowHeight);
        }

        ASSERT(!extraRowSpanningHeight);

        // Getting total changed height in the table
        extraHeightToPropagate = m_rowPos[spanningCellEndIndex] - originalBeforePosition;
    }

    if (extraHeightToPropagate) {
        // Apply changed height by rowSpan cells to rows present at the end of the table
        for (unsigned row = lastRowIndex + lastRowSpan + 1; row <= m_grid.size(); row++)
            m_rowPos[row] += extraHeightToPropagate;
    }
}

// Find out the baseline of the cell
// If the cell's baseline is more then the row's baseline then the cell's baseline become the row's baseline
// and if the row's baseline goes out of the row's boundries then adjust row height accordingly.
void LayoutTableSection::updateBaselineForCell(LayoutTableCell* cell, unsigned row, int& baselineDescent)
{
    if (!cell->isBaselineAligned())
        return;

    // Ignoring the intrinsic padding as it depends on knowing the row's baseline, which won't be accurate
    // until the end of this function.
    int baselinePosition = cell->cellBaselinePosition() - cell->intrinsicPaddingBefore();
    if (baselinePosition > cell->borderBefore() + (cell->paddingBefore() - cell->intrinsicPaddingBefore())) {
        m_grid[row].baseline = std::max(m_grid[row].baseline, baselinePosition);

        int cellStartRowBaselineDescent = 0;
        if (cell->rowSpan() == 1) {
            baselineDescent = std::max(baselineDescent, cell->logicalHeightForRowSizing() - baselinePosition);
            cellStartRowBaselineDescent = baselineDescent;
        }
        m_rowPos[row + 1] = std::max<int>(m_rowPos[row + 1], m_rowPos[row] + m_grid[row].baseline + cellStartRowBaselineDescent);
    }
}

int LayoutTableSection::calcRowLogicalHeight()
{
#if ENABLE(ASSERT)
    SetLayoutNeededForbiddenScope layoutForbiddenScope(*this);
#endif

    ASSERT(!needsLayout());

    LayoutTableCell* cell;

    // We may have to forcefully lay out cells here, in which case we need a layout
    // state. Technically, we should also push state for the row, but since rows don't push a
    // coordinate transform, that's not necessary.
    LayoutState state(*this, locationOffset());

    m_rowPos.resize(m_grid.size() + 1);

    // We ignore the border-spacing on any non-top section as it is already included in the previous section's last row position.
    if (this == table()->topSection())
        m_rowPos[0] = table()->vBorderSpacing();
    else
        m_rowPos[0] = 0;

    SpanningLayoutTableCells rowSpanCells;
#if ENABLE(ASSERT)
    HashSet<const LayoutTableCell*> uniqueCells;
#endif

    for (unsigned r = 0; r < m_grid.size(); r++) {
        m_grid[r].baseline = -1;
        int baselineDescent = 0;

        if (m_grid[r].logicalHeight.isSpecified()) {
            // Our base size is the biggest logical height from our cells' styles (excluding row spanning cells).
            m_rowPos[r + 1] = std::max(m_rowPos[r] + minimumValueForLength(m_grid[r].logicalHeight, LayoutUnit()).round(), 0);
        } else {
            // Non-specified lengths are ignored because the row already accounts for the cells
            // intrinsic logical height.
            m_rowPos[r + 1] = std::max(m_rowPos[r], 0);
        }

        Row& row = m_grid[r].row;
        unsigned totalCols = row.size();
        LayoutTableCell* lastRowSpanCell = nullptr;

        for (unsigned c = 0; c < totalCols; c++) {
            CellStruct& current = cellAt(r, c);
            for (unsigned i = 0; i < current.cells.size(); i++) {
                cell = current.cells[i];
                if (current.inColSpan && cell->rowSpan() == 1)
                    continue;

                if (cell->rowSpan() > 1) {
                    // For row spanning cells, we only handle them for the first row they span. This ensures we take their baseline into account.
                    if (lastRowSpanCell != cell && cell->rowIndex() == r) {
#if ENABLE(ASSERT)
                        ASSERT(!uniqueCells.contains(cell));
                        uniqueCells.add(cell);
#endif

                        rowSpanCells.append(cell);
                        lastRowSpanCell = cell;
                    }
                }

                if (cell->rowIndex() == r && cell->hasOverrideLogicalContentHeight()) {
                    cell->clearIntrinsicPadding();
                    cell->clearOverrideSize();
                    cell->forceChildLayout();
                }

                if (cell->rowSpan() == 1)
                    m_rowPos[r + 1] = std::max(m_rowPos[r + 1], m_rowPos[r] + cell->logicalHeightForRowSizing());

                // Find out the baseline. The baseline is set on the first row in a rowSpan.
                if (cell->rowIndex() == r)
                    updateBaselineForCell(cell, r, baselineDescent);
            }
        }

        // Add the border-spacing to our final position.
        m_rowPos[r + 1] += borderSpacingForRow(r);
        m_rowPos[r + 1] = std::max(m_rowPos[r + 1], m_rowPos[r]);
    }

    if (!rowSpanCells.isEmpty())
        distributeRowSpanHeightToRows(rowSpanCells);

    ASSERT(!needsLayout());

    return m_rowPos[m_grid.size()];
}

void LayoutTableSection::layout()
{
    ASSERT(needsLayout());
    LayoutAnalyzer::Scope analyzer(*this);
    ASSERT(!needsCellRecalc());
    ASSERT(!table()->needsSectionRecalc());

    // addChild may over-grow m_grid but we don't want to throw away the memory too early as addChild
    // can be called in a loop (e.g during parsing). Doing it now ensures we have a stable-enough structure.
    m_grid.shrinkToFit();

    LayoutState state(*this, locationOffset());

    const Vector<int>& columnPos = table()->effectiveColumnPositions();

    SubtreeLayoutScope layouter(*this);
    for (unsigned r = 0; r < m_grid.size(); ++r) {
        Row& row = m_grid[r].row;
        unsigned cols = row.size();
        // First, propagate our table layout's information to the cells. This will mark the row as needing layout
        // if there was a column logical width change.
        for (unsigned startColumn = 0; startColumn < cols; ++startColumn) {
            CellStruct& current = row[startColumn];
            LayoutTableCell* cell = current.primaryCell();
            if (!cell || current.inColSpan)
                continue;

            unsigned endCol = startColumn;
            unsigned cspan = cell->colSpan();
            while (cspan && endCol < cols) {
                ASSERT(endCol < table()->effectiveColumns().size());
                cspan -= table()->effectiveColumns()[endCol].span;
                endCol++;
            }
            int tableLayoutLogicalWidth = columnPos[endCol] - columnPos[startColumn] - table()->hBorderSpacing();
            cell->setCellLogicalWidth(tableLayoutLogicalWidth, layouter);
        }

        if (LayoutTableRow* rowLayoutObject = m_grid[r].rowLayoutObject) {
            if (!rowLayoutObject->needsLayout())
                rowLayoutObject->markForPaginationRelayoutIfNeeded(layouter);
            rowLayoutObject->layoutIfNeeded();
        }
    }

    clearNeedsLayout();
}

void LayoutTableSection::distributeExtraLogicalHeightToPercentRows(int& extraLogicalHeight, int totalPercent)
{
    if (!totalPercent)
        return;

    unsigned totalRows = m_grid.size();
    int totalHeight = m_rowPos[totalRows] + extraLogicalHeight;
    int totalLogicalHeightAdded = 0;
    totalPercent = std::min(totalPercent, 100);
    int rowHeight = m_rowPos[1] - m_rowPos[0];
    for (unsigned r = 0; r < totalRows; ++r) {
        // TODO(alancutter): Make this work correctly for calc lengths.
        if (totalPercent > 0 && m_grid[r].logicalHeight.hasPercent()) {
            int toAdd = std::min<int>(extraLogicalHeight, (totalHeight * m_grid[r].logicalHeight.percent() / 100) - rowHeight);
            // If toAdd is negative, then we don't want to shrink the row (this bug
            // affected Outlook Web Access).
            toAdd = std::max(0, toAdd);
            totalLogicalHeightAdded += toAdd;
            extraLogicalHeight -= toAdd;
            totalPercent -= m_grid[r].logicalHeight.percent();
        }
        ASSERT(totalRows >= 1);
        if (r < totalRows - 1)
            rowHeight = m_rowPos[r + 2] - m_rowPos[r + 1];
        m_rowPos[r + 1] += totalLogicalHeightAdded;
    }
}

void LayoutTableSection::distributeExtraLogicalHeightToAutoRows(int& extraLogicalHeight, unsigned autoRowsCount)
{
    if (!autoRowsCount)
        return;

    int totalLogicalHeightAdded = 0;
    for (unsigned r = 0; r < m_grid.size(); ++r) {
        if (autoRowsCount > 0 && m_grid[r].logicalHeight.isAuto()) {
            // Recomputing |extraLogicalHeightForRow| guarantees that we properly ditribute round |extraLogicalHeight|.
            int extraLogicalHeightForRow = extraLogicalHeight / autoRowsCount;
            totalLogicalHeightAdded += extraLogicalHeightForRow;
            extraLogicalHeight -= extraLogicalHeightForRow;
            --autoRowsCount;
        }
        m_rowPos[r + 1] += totalLogicalHeightAdded;
    }
}

void LayoutTableSection::distributeRemainingExtraLogicalHeight(int& extraLogicalHeight)
{
    unsigned totalRows = m_grid.size();

    if (extraLogicalHeight <= 0 || !m_rowPos[totalRows])
        return;

    // FIXME: m_rowPos[totalRows] - m_rowPos[0] is the total rows' size.
    int totalRowSize = m_rowPos[totalRows];
    int totalLogicalHeightAdded = 0;
    int previousRowPosition = m_rowPos[0];
    for (unsigned r = 0; r < totalRows; r++) {
        // weight with the original height
        totalLogicalHeightAdded += extraLogicalHeight * (m_rowPos[r + 1] - previousRowPosition) / totalRowSize;
        previousRowPosition = m_rowPos[r + 1];
        m_rowPos[r + 1] += totalLogicalHeightAdded;
    }

    extraLogicalHeight -= totalLogicalHeightAdded;
}

int LayoutTableSection::distributeExtraLogicalHeightToRows(int extraLogicalHeight)
{
    if (!extraLogicalHeight)
        return extraLogicalHeight;

    unsigned totalRows = m_grid.size();
    if (!totalRows)
        return extraLogicalHeight;

    if (!m_rowPos[totalRows] && nextSibling())
        return extraLogicalHeight;

    unsigned autoRowsCount = 0;
    int totalPercent = 0;
    for (unsigned r = 0; r < totalRows; r++) {
        if (m_grid[r].logicalHeight.isAuto())
            ++autoRowsCount;
        else if (m_grid[r].logicalHeight.hasPercent())
            totalPercent += m_grid[r].logicalHeight.percent();
    }

    int remainingExtraLogicalHeight = extraLogicalHeight;
    distributeExtraLogicalHeightToPercentRows(remainingExtraLogicalHeight, totalPercent);
    distributeExtraLogicalHeightToAutoRows(remainingExtraLogicalHeight, autoRowsCount);
    distributeRemainingExtraLogicalHeight(remainingExtraLogicalHeight);
    return extraLogicalHeight - remainingExtraLogicalHeight;
}

static bool shouldFlexCellChild(LayoutObject* cellDescendant)
{
    return cellDescendant->isAtomicInlineLevel() || (cellDescendant->isBox() && toLayoutBox(cellDescendant)->scrollsOverflow());
}

void LayoutTableSection::layoutRows()
{
#if ENABLE(ASSERT)
    SetLayoutNeededForbiddenScope layoutForbiddenScope(*this);
#endif

    ASSERT(!needsLayout());

    LayoutAnalyzer::Scope analyzer(*this);

    // FIXME: Changing the height without a layout can change the overflow so it seems wrong.

    unsigned totalRows = m_grid.size();

    // Set the width of our section now.  The rows will also be this width.
    setLogicalWidth(table()->contentLogicalWidth());
    m_overflow.clear();
    m_overflowingCells.clear();
    m_forceSlowPaintPathWithOverflowingCell = false;

    int vspacing = table()->vBorderSpacing();
    unsigned nEffCols = table()->numEffectiveColumns();

    LayoutState state(*this, locationOffset());

    for (unsigned r = 0; r < totalRows; r++) {
        // Set the row's x/y position and width/height.
        LayoutTableRow* rowLayoutObject = m_grid[r].rowLayoutObject;
        if (rowLayoutObject) {
            rowLayoutObject->setLocation(LayoutPoint(0, m_rowPos[r]));
            rowLayoutObject->setLogicalWidth(logicalWidth());
            rowLayoutObject->setLogicalHeight(LayoutUnit(m_rowPos[r + 1] - m_rowPos[r] - vspacing));
            rowLayoutObject->updateLayerTransformAfterLayout();
            rowLayoutObject->clearAllOverflows();
            rowLayoutObject->addVisualEffectOverflow();
        }

        int rowHeightIncreaseForPagination = 0;

        for (unsigned c = 0; c < nEffCols; c++) {
            CellStruct& cs = cellAt(r, c);
            LayoutTableCell* cell = cs.primaryCell();

            if (!cell || cs.inColSpan)
                continue;

            int rowIndex = cell->rowIndex();
            int rHeight = m_rowPos[rowIndex + cell->rowSpan()] - m_rowPos[rowIndex] - vspacing;

            // Force percent height children to lay themselves out again.
            // This will cause these children to grow to fill the cell.
            // FIXME: There is still more work to do here to fully match WinIE (should
            // it become necessary to do so).  In quirks mode, WinIE behaves like we
            // do, but it will clip the cells that spill out of the table section.  In
            // strict mode, Mozilla and WinIE both regrow the table to accommodate the
            // new height of the cell (thus letting the percentages cause growth one
            // time only).  We may also not be handling row-spanning cells correctly.
            //
            // Note also the oddity where replaced elements always flex, and yet blocks/tables do
            // not necessarily flex.  WinIE is crazy and inconsistent, and we can't hope to
            // match the behavior perfectly, but we'll continue to refine it as we discover new
            // bugs. :)
            bool cellChildrenFlex = false;
            bool flexAllChildren = cell->style()->logicalHeight().isFixed()
                || (!table()->style()->logicalHeight().isAuto() && rHeight != cell->logicalHeight());

            for (LayoutObject* child = cell->firstChild(); child; child = child->nextSibling()) {
                if (!child->isText() && child->style()->logicalHeight().hasPercent()
                    && (flexAllChildren || shouldFlexCellChild(child))
                    && (!child->isTable() || toLayoutTable(child)->hasSections())) {
                    cellChildrenFlex = true;
                    break;
                }
            }

            if (!cellChildrenFlex) {
                if (TrackedLayoutBoxListHashSet* percentHeightDescendants = cell->percentHeightDescendants()) {
                    for (auto* descendant : *percentHeightDescendants) {
                        if (flexAllChildren || shouldFlexCellChild(descendant)) {
                            cellChildrenFlex = true;
                            break;
                        }
                    }
                }
            }

            if (cellChildrenFlex) {
                // Alignment within a cell is based off the calculated
                // height, which becomes irrelevant once the cell has
                // been resized based off its percentage.
                cell->setOverrideLogicalContentHeightFromRowHeight(LayoutUnit(rHeight));
                cell->forceChildLayout();

                // If the baseline moved, we may have to update the data for our row. Find out the new baseline.
                if (cell->isBaselineAligned()) {
                    int baseline = cell->cellBaselinePosition();
                    if (baseline > cell->borderBefore() + cell->paddingBefore())
                        m_grid[r].baseline = std::max(m_grid[r].baseline, baseline);
                }
            }

            SubtreeLayoutScope layouter(*cell);
            cell->computeIntrinsicPadding(rHeight, layouter);

            LayoutRect oldCellRect = cell->frameRect();

            setLogicalPositionForCell(cell, c);

            if (!cell->needsLayout())
                cell->markForPaginationRelayoutIfNeeded(layouter);

            cell->layoutIfNeeded();

            // FIXME: Make pagination work with vertical tables.
            if (view()->layoutState()->pageLogicalHeight() && cell->logicalHeight() != rHeight) {
                // FIXME: Pagination might have made us change size. For now just shrink or grow the cell to fit without doing a relayout.
                // We'll also do a basic increase of the row height to accommodate the cell if it's bigger, but this isn't quite right
                // either. It's at least stable though and won't result in an infinite # of relayouts that may never stabilize.
                LayoutUnit oldLogicalHeight = cell->logicalHeight();
                if (oldLogicalHeight > rHeight)
                    rowHeightIncreaseForPagination = std::max<int>(rowHeightIncreaseForPagination, oldLogicalHeight - rHeight);
                cell->setLogicalHeight(LayoutUnit(rHeight));
                cell->computeOverflow(oldLogicalHeight, false);
            }

            if (rowLayoutObject)
                rowLayoutObject->addOverflowFromCell(cell);

            LayoutSize childOffset(cell->location() - oldCellRect.location());
            if (childOffset.width() || childOffset.height()) {
                // If the child moved, we have to issue paint invalidations to it as well as any floating/positioned
                // descendants. An exception is if we need a layout. In this case, we know we're going to
                // issue paint invalidations ourselves (and the child) anyway.
                if (!table()->selfNeedsLayout())
                    cell->setMayNeedPaintInvalidation();
            }
        }
        if (rowHeightIncreaseForPagination) {
            for (unsigned rowIndex = r + 1; rowIndex <= totalRows; rowIndex++)
                m_rowPos[rowIndex] += rowHeightIncreaseForPagination;
            for (unsigned c = 0; c < nEffCols; ++c) {
                Vector<LayoutTableCell*, 1>& cells = cellAt(r, c).cells;
                for (size_t i = 0; i < cells.size(); ++i) {
                    LayoutUnit oldLogicalHeight = cells[i]->logicalHeight();
                    cells[i]->setLogicalHeight(oldLogicalHeight + rowHeightIncreaseForPagination);
                    cells[i]->computeOverflow(oldLogicalHeight, false);
                }
            }
        }
    }

    ASSERT(!needsLayout());

    setLogicalHeight(LayoutUnit(m_rowPos[totalRows]));

    computeOverflowFromCells(totalRows, nEffCols);
}

void LayoutTableSection::computeOverflowFromCells()
{
    unsigned totalRows = m_grid.size();
    unsigned nEffCols = table()->numEffectiveColumns();
    computeOverflowFromCells(totalRows, nEffCols);
}

void LayoutTableSection::computeOverflowFromCells(unsigned totalRows, unsigned nEffCols)
{
    unsigned totalCellsCount = nEffCols * totalRows;
    unsigned maxAllowedOverflowingCellsCount = totalCellsCount < gMinTableSizeToUseFastPaintPathWithOverflowingCell ? 0 : gMaxAllowedOverflowingCellRatioForFastPaintPath * totalCellsCount;

#if ENABLE(ASSERT)
    bool hasOverflowingCell = false;
#endif
    // Now that our height has been determined, add in overflow from cells.
    for (unsigned r = 0; r < totalRows; r++) {
        for (unsigned c = 0; c < nEffCols; c++) {
            CellStruct& cs = cellAt(r, c);
            LayoutTableCell* cell = cs.primaryCell();
            if (!cell || cs.inColSpan)
                continue;
            if (r < totalRows - 1 && cell == primaryCellAt(r + 1, c))
                continue;
            addOverflowFromChild(cell);
#if ENABLE(ASSERT)
            hasOverflowingCell |= cell->hasVisualOverflow();
#endif
            if (cell->hasVisualOverflow() && !m_forceSlowPaintPathWithOverflowingCell) {
                m_overflowingCells.add(cell);
                if (m_overflowingCells.size() > maxAllowedOverflowingCellsCount) {
                    // We need to set m_forcesSlowPaintPath only if there is a least one overflowing cells as the hit testing code rely on this information.
                    m_forceSlowPaintPathWithOverflowingCell = true;
                    // The slow path does not make any use of the overflowing cells info, don't hold on to the memory.
                    m_overflowingCells.clear();
                }
            }
        }
    }

    ASSERT(hasOverflowingCell == this->hasOverflowingCell());
}

int LayoutTableSection::calcBlockDirectionOuterBorder(BlockBorderSide side) const
{
    unsigned totalCols = table()->numEffectiveColumns();
    if (!m_grid.size() || !totalCols)
        return 0;

    int borderWidth = 0;

    const BorderValue& sb = side == BorderBefore ? style()->borderBefore() : style()->borderAfter();
    if (sb.style() == BorderStyleHidden)
        return -1;
    if (sb.style() > BorderStyleHidden)
        borderWidth = sb.width();

    const BorderValue& rb = side == BorderBefore ? firstRow()->style()->borderBefore() : lastRow()->style()->borderAfter();
    if (rb.style() == BorderStyleHidden)
        return -1;
    if (rb.style() > BorderStyleHidden && rb.width() > borderWidth)
        borderWidth = rb.width();

    bool allHidden = true;
    for (unsigned c = 0; c < totalCols; c++) {
        const CellStruct& current = cellAt(side == BorderBefore ? 0 : m_grid.size() - 1, c);
        if (current.inColSpan || !current.hasCells())
            continue;
        const ComputedStyle& primaryCellStyle = current.primaryCell()->styleRef();
        const BorderValue& cb = side == BorderBefore ? primaryCellStyle.borderBefore() : primaryCellStyle.borderAfter(); // FIXME: Make this work with perpendicular and flipped cells.
        // FIXME: Don't repeat for the same col group
        LayoutTableCol* col = table()->colElementAtAbsoluteColumn(c).innermostColOrColGroup();
        if (col) {
            const BorderValue& gb = side == BorderBefore ? col->style()->borderBefore() : col->style()->borderAfter();
            if (gb.style() == BorderStyleHidden || cb.style() == BorderStyleHidden)
                continue;
            allHidden = false;
            if (gb.style() > BorderStyleHidden && gb.width() > borderWidth)
                borderWidth = gb.width();
            if (cb.style() > BorderStyleHidden && cb.width() > borderWidth)
                borderWidth = cb.width();
        } else {
            if (cb.style() == BorderStyleHidden)
                continue;
            allHidden = false;
            if (cb.style() > BorderStyleHidden && cb.width() > borderWidth)
                borderWidth = cb.width();
        }
    }
    if (allHidden)
        return -1;

    if (side == BorderAfter)
        borderWidth++; // Distribute rounding error
    return borderWidth / 2;
}

int LayoutTableSection::calcInlineDirectionOuterBorder(InlineBorderSide side) const
{
    unsigned totalCols = table()->numEffectiveColumns();
    if (!m_grid.size() || !totalCols)
        return 0;
    unsigned colIndex = side == BorderStart ? 0 : totalCols - 1;

    int borderWidth = 0;

    const BorderValue& sb = side == BorderStart ? style()->borderStart() : style()->borderEnd();
    if (sb.style() == BorderStyleHidden)
        return -1;
    if (sb.style() > BorderStyleHidden)
        borderWidth = sb.width();

    if (LayoutTableCol* col = table()->colElementAtAbsoluteColumn(colIndex).innermostColOrColGroup()) {
        const BorderValue& gb = side == BorderStart ? col->style()->borderStart() : col->style()->borderEnd();
        if (gb.style() == BorderStyleHidden)
            return -1;
        if (gb.style() > BorderStyleHidden && gb.width() > borderWidth)
            borderWidth = gb.width();
    }

    bool allHidden = true;
    for (unsigned r = 0; r < m_grid.size(); r++) {
        const CellStruct& current = cellAt(r, colIndex);
        if (!current.hasCells())
            continue;
        // FIXME: Don't repeat for the same cell
        const ComputedStyle& primaryCellStyle = current.primaryCell()->styleRef();
        const ComputedStyle& primaryCellParentStyle = current.primaryCell()->parent()->styleRef();
        const BorderValue& cb = side == BorderStart ? primaryCellStyle.borderStart() : primaryCellStyle.borderEnd(); // FIXME: Make this work with perpendicular and flipped cells.
        const BorderValue& rb = side == BorderStart ? primaryCellParentStyle.borderStart() : primaryCellParentStyle.borderEnd();
        if (cb.style() == BorderStyleHidden || rb.style() == BorderStyleHidden)
            continue;
        allHidden = false;
        if (cb.style() > BorderStyleHidden && cb.width() > borderWidth)
            borderWidth = cb.width();
        if (rb.style() > BorderStyleHidden && rb.width() > borderWidth)
            borderWidth = rb.width();
    }
    if (allHidden)
        return -1;

    if ((side == BorderStart) != table()->style()->isLeftToRightDirection())
        borderWidth++; // Distribute rounding error
    return borderWidth / 2;
}

void LayoutTableSection::recalcOuterBorder()
{
    m_outerBorderBefore = calcBlockDirectionOuterBorder(BorderBefore);
    m_outerBorderAfter = calcBlockDirectionOuterBorder(BorderAfter);
    m_outerBorderStart = calcInlineDirectionOuterBorder(BorderStart);
    m_outerBorderEnd = calcInlineDirectionOuterBorder(BorderEnd);
}

int LayoutTableSection::firstLineBoxBaseline() const
{
    if (!m_grid.size())
        return -1;

    int firstLineBaseline = m_grid[0].baseline;
    if (firstLineBaseline >= 0)
        return firstLineBaseline + m_rowPos[0];

    const Row& firstRow = m_grid[0].row;
    for (size_t i = 0; i < firstRow.size(); ++i) {
        const CellStruct& cs = firstRow.at(i);
        const LayoutTableCell* cell = cs.primaryCell();
        if (cell)
            firstLineBaseline = std::max<int>(firstLineBaseline, cell->logicalTop() + cell->borderBefore() + cell->paddingBefore() + cell->contentLogicalHeight());
    }

    return firstLineBaseline;
}

void LayoutTableSection::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
{
    TableSectionPainter(*this).paint(paintInfo, paintOffset);
}

LayoutRect LayoutTableSection::logicalRectForWritingModeAndDirection(const LayoutRect& rect) const
{
    LayoutRect tableAlignedRect(rect);

    flipForWritingMode(tableAlignedRect);

    if (!style()->isHorizontalWritingMode())
        tableAlignedRect = tableAlignedRect.transposedRect();

    const Vector<int>& columnPos = table()->effectiveColumnPositions();
    // FIXME: The table's direction should determine our row's direction, not the section's (see bug 96691).
    if (!style()->isLeftToRightDirection())
        tableAlignedRect.setX(columnPos[columnPos.size() - 1] - tableAlignedRect.maxX());

    return tableAlignedRect;
}

CellSpan LayoutTableSection::dirtiedRows(const LayoutRect& damageRect) const
{
    if (m_forceSlowPaintPathWithOverflowingCell)
        return fullTableRowSpan();

    CellSpan coveredRows = spannedRows(damageRect);

    // To issue paint invalidations for the border we might need to paint invalidate the first
    // or last row even if they are not spanned themselves.
    RELEASE_ASSERT(coveredRows.start() < m_rowPos.size());
    if (coveredRows.start() == m_rowPos.size() - 1
        && m_rowPos[m_rowPos.size() - 1] + table()->outerBorderAfter() >= damageRect.y())
        coveredRows.decreaseStart();

    if (!coveredRows.end()
        && m_rowPos[0] - table()->outerBorderBefore() <= damageRect.maxY())
        coveredRows.increaseEnd();

    coveredRows.ensureConsistency(m_grid.size());

    return coveredRows;
}

CellSpan LayoutTableSection::dirtiedEffectiveColumns(const LayoutRect& damageRect) const
{
    if (m_forceSlowPaintPathWithOverflowingCell)
        return fullTableEffectiveColumnSpan();

    CellSpan coveredColumns = spannedEffectiveColumns(damageRect);

    const Vector<int>& columnPos = table()->effectiveColumnPositions();
    // To issue paint invalidations for the border we might need to paint invalidate the first
    // or last column even if they are not spanned themselves.
    RELEASE_ASSERT(coveredColumns.start() < columnPos.size());
    if (coveredColumns.start() == columnPos.size() - 1
        && columnPos[columnPos.size() - 1] + table()->outerBorderEnd() >= damageRect.x())
        coveredColumns.decreaseStart();

    if (!coveredColumns.end()
        && columnPos[0] - table()->outerBorderStart() <= damageRect.maxX())
        coveredColumns.increaseEnd();

    coveredColumns.ensureConsistency(table()->numEffectiveColumns());

    return coveredColumns;
}

CellSpan LayoutTableSection::spannedRows(const LayoutRect& flippedRect) const
{
    // Find the first row that starts after rect top.
    unsigned nextRow = std::upper_bound(m_rowPos.begin(), m_rowPos.end(), flippedRect.y()) - m_rowPos.begin();

    if (nextRow == m_rowPos.size())
        return CellSpan(m_rowPos.size() - 1, m_rowPos.size() - 1); // After all rows.

    unsigned startRow = nextRow > 0 ? nextRow - 1 : 0;

    // Find the first row that starts after rect bottom.
    unsigned endRow;
    if (m_rowPos[nextRow] >= flippedRect.maxY()) {
        endRow = nextRow;
    } else {
        endRow = std::upper_bound(m_rowPos.begin() + nextRow, m_rowPos.end(), flippedRect.maxY()) - m_rowPos.begin();
        if (endRow == m_rowPos.size())
            endRow = m_rowPos.size() - 1;
    }

    return CellSpan(startRow, endRow);
}

CellSpan LayoutTableSection::spannedEffectiveColumns(const LayoutRect& flippedRect) const
{
    const Vector<int>& columnPos = table()->effectiveColumnPositions();

    // Find the first column that starts after rect left.
    // lower_bound doesn't handle the edge between two cells properly as it would wrongly return the
    // cell on the logical top/left.
    // upper_bound on the other hand properly returns the cell on the logical bottom/right, which also
    // matches the behavior of other browsers.
    unsigned nextColumn = std::upper_bound(columnPos.begin(), columnPos.end(), flippedRect.x()) - columnPos.begin();

    if (nextColumn == columnPos.size())
        return CellSpan(columnPos.size() - 1, columnPos.size() - 1); // After all columns.

    unsigned startColumn = nextColumn > 0 ? nextColumn - 1 : 0;

    // Find the first column that starts after rect right.
    unsigned endColumn;
    if (columnPos[nextColumn] >= flippedRect.maxX()) {
        endColumn = nextColumn;
    } else {
        endColumn = std::upper_bound(columnPos.begin() + nextColumn, columnPos.end(), flippedRect.maxX()) - columnPos.begin();
        if (endColumn == columnPos.size())
            endColumn = columnPos.size() - 1;
    }

    return CellSpan(startColumn, endColumn);
}


void LayoutTableSection::imageChanged(WrappedImagePtr, const IntRect*)
{
    // FIXME: Examine cells and issue paint invalidations of only the rect the image paints in.
    setShouldDoFullPaintInvalidation();
}

void LayoutTableSection::recalcCells()
{
    ASSERT(m_needsCellRecalc);
    // We reset the flag here to ensure that |addCell| works. This is safe to do as
    // fillRowsWithDefaultStartingAtPosition makes sure we match the table's columns
    // representation.
    m_needsCellRecalc = false;

    m_cCol = 0;
    m_cRow = 0;
    m_grid.clear();

    for (LayoutTableRow* row = firstRow(); row; row = row->nextRow()) {
        unsigned insertionRow = m_cRow;
        ++m_cRow;
        m_cCol = 0;
        ensureRows(m_cRow);

        m_grid[insertionRow].rowLayoutObject = row;
        row->setRowIndex(insertionRow);
        setRowLogicalHeightToRowStyleLogicalHeight(m_grid[insertionRow]);

        for (LayoutTableCell* cell = row->firstCell(); cell; cell = cell->nextCell())
            addCell(cell, row);
    }

    m_grid.shrinkToFit();
    setNeedsLayoutAndFullPaintInvalidation(LayoutInvalidationReason::Unknown);
}

// FIXME: This function could be made O(1) in certain cases (like for the non-most-constrainive cells' case).
void LayoutTableSection::rowLogicalHeightChanged(LayoutTableRow* row)
{
    if (needsCellRecalc())
        return;

    unsigned rowIndex = row->rowIndex();
    setRowLogicalHeightToRowStyleLogicalHeight(m_grid[rowIndex]);

    for (LayoutTableCell* cell = m_grid[rowIndex].rowLayoutObject->firstCell(); cell; cell = cell->nextCell())
        updateLogicalHeightForCell(m_grid[rowIndex], cell);
}

void LayoutTableSection::setNeedsCellRecalc()
{
    m_needsCellRecalc = true;
    if (LayoutTable* t = table())
        t->setNeedsSectionRecalc();
}

unsigned LayoutTableSection::numEffectiveColumns() const
{
    unsigned result = 0;

    for (unsigned r = 0; r < m_grid.size(); ++r) {
        for (unsigned c = result; c < table()->numEffectiveColumns(); ++c) {
            const CellStruct& cell = cellAt(r, c);
            if (cell.hasCells() || cell.inColSpan)
                result = c;
        }
    }

    return result + 1;
}

const BorderValue& LayoutTableSection::borderAdjoiningStartCell(const LayoutTableCell* cell) const
{
    ASSERT(cell->isFirstOrLastCellInRow());
    return hasSameDirectionAs(cell) ? style()->borderStart() : style()->borderEnd();
}

const BorderValue& LayoutTableSection::borderAdjoiningEndCell(const LayoutTableCell* cell) const
{
    ASSERT(cell->isFirstOrLastCellInRow());
    return hasSameDirectionAs(cell) ? style()->borderEnd() : style()->borderStart();
}

const LayoutTableCell* LayoutTableSection::firstRowCellAdjoiningTableStart() const
{
    unsigned adjoiningStartCellColumnIndex = hasSameDirectionAs(table()) ? 0 : table()->lastEffectiveColumnIndex();
    return cellAt(0, adjoiningStartCellColumnIndex).primaryCell();
}

const LayoutTableCell* LayoutTableSection::firstRowCellAdjoiningTableEnd() const
{
    unsigned adjoiningEndCellColumnIndex = hasSameDirectionAs(table()) ? table()->lastEffectiveColumnIndex() : 0;
    return cellAt(0, adjoiningEndCellColumnIndex).primaryCell();
}

void LayoutTableSection::appendEffectiveColumn(unsigned pos)
{
    ASSERT(!m_needsCellRecalc);

    for (unsigned row = 0; row < m_grid.size(); ++row)
        m_grid[row].row.resize(pos + 1);
}

void LayoutTableSection::splitEffectiveColumn(unsigned pos, unsigned first)
{
    ASSERT(!m_needsCellRecalc);

    if (m_cCol > pos)
        m_cCol++;
    for (unsigned row = 0; row < m_grid.size(); ++row) {
        Row& r = m_grid[row].row;
        r.insert(pos + 1, CellStruct());
        if (r[pos].hasCells()) {
            r[pos + 1].cells.appendVector(r[pos].cells);
            LayoutTableCell* cell = r[pos].primaryCell();
            ASSERT(cell);
            ASSERT(cell->colSpan() >= (r[pos].inColSpan ? 1u : 0));
            unsigned colleft = cell->colSpan() - r[pos].inColSpan;
            if (first > colleft)
                r[pos + 1].inColSpan = 0;
            else
                r[pos + 1].inColSpan = first + r[pos].inColSpan;
        } else {
            r[pos + 1].inColSpan = 0;
        }
    }
}

// Hit Testing
bool LayoutTableSection::nodeAtPoint(HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction action)
{
    // If we have no children then we have nothing to do.
    if (!firstRow())
        return false;

    // Table sections cannot ever be hit tested.  Effectively they do not exist.
    // Just forward to our children always.
    LayoutPoint adjustedLocation = accumulatedOffset + location();

    if (hasOverflowClip() && !locationInContainer.intersects(overflowClipRect(adjustedLocation)))
        return false;

    if (hasOverflowingCell()) {
        for (LayoutTableRow* row = lastRow(); row; row = row->previousRow()) {
            // FIXME: We have to skip over inline flows, since they can show up inside table rows
            // at the moment (a demoted inline <form> for example). If we ever implement a
            // table-specific hit-test method (which we should do for performance reasons anyway),
            // then we can remove this check.
            if (!row->hasSelfPaintingLayer()) {
                LayoutPoint childPoint = flipForWritingModeForChild(row, adjustedLocation);
                if (row->nodeAtPoint(result, locationInContainer, childPoint, action)) {
                    updateHitTestResult(result, toLayoutPoint(locationInContainer.point() - childPoint));
                    return true;
                }
            }
        }
        return false;
    }

    recalcCellsIfNeeded();

    LayoutRect hitTestRect = LayoutRect(locationInContainer.boundingBox());
    hitTestRect.moveBy(-adjustedLocation);

    LayoutRect tableAlignedRect = logicalRectForWritingModeAndDirection(hitTestRect);
    CellSpan rowSpan = spannedRows(tableAlignedRect);
    CellSpan columnSpan = spannedEffectiveColumns(tableAlignedRect);

    // Now iterate over the spanned rows and columns.
    for (unsigned hitRow = rowSpan.start(); hitRow < rowSpan.end(); ++hitRow) {
        for (unsigned hitColumn = columnSpan.start(); hitColumn < columnSpan.end(); ++hitColumn) {
            CellStruct& current = cellAt(hitRow, hitColumn);

            // If the cell is empty, there's nothing to do
            if (!current.hasCells())
                continue;

            for (unsigned i = current.cells.size() ; i; ) {
                --i;
                LayoutTableCell* cell = current.cells[i];
                LayoutPoint cellPoint = flipForWritingModeForChild(cell, adjustedLocation);
                if (static_cast<LayoutObject*>(cell)->nodeAtPoint(result, locationInContainer, cellPoint, action)) {
                    updateHitTestResult(result, locationInContainer.point() - toLayoutSize(cellPoint));
                    return true;
                }
            }
            if (!result.hitTestRequest().listBased())
                break;
        }
        if (!result.hitTestRequest().listBased())
            break;
    }

    return false;
}

void LayoutTableSection::removeCachedCollapsedBorders(const LayoutTableCell* cell)
{
    if (!table()->collapseBorders())
        return;

    for (int side = CBSBefore; side <= CBSEnd; ++side)
        m_cellsCollapsedBorders.remove(std::make_pair(cell, side));
}

bool LayoutTableSection::setCachedCollapsedBorder(const LayoutTableCell* cell, CollapsedBorderSide side, const CollapsedBorderValue& border)
{
    ASSERT(table()->collapseBorders());
    CellsCollapsedBordersMap::iterator it = m_cellsCollapsedBorders.find(std::make_pair(cell, side));
    if (it == m_cellsCollapsedBorders.end()) {
        if (!border.isVisible())
            return false;
        m_cellsCollapsedBorders.add(std::make_pair(cell, side), border);
        return true;
    }
    if (!border.isVisible()) {
        m_cellsCollapsedBorders.remove(it);
        return true;
    }
    if (!it->value.equals(border)) {
        it->value = border;
        return true;
    }
    return false;
}

const CollapsedBorderValue* LayoutTableSection::cachedCollapsedBorder(const LayoutTableCell* cell, CollapsedBorderSide side) const
{
    ASSERT(table()->collapseBorders());
    CellsCollapsedBordersMap::const_iterator it = m_cellsCollapsedBorders.find(std::make_pair(cell, side));
    return it == m_cellsCollapsedBorders.end() ? nullptr : &it->value;
}

LayoutTableSection* LayoutTableSection::createAnonymousWithParent(const LayoutObject* parent)
{
    RefPtr<ComputedStyle> newStyle = ComputedStyle::createAnonymousStyleWithDisplay(parent->styleRef(), TABLE_ROW_GROUP);
    LayoutTableSection* newSection = new LayoutTableSection(nullptr);
    newSection->setDocumentForAnonymous(&parent->document());
    newSection->setStyle(newStyle.release());
    return newSection;
}

void LayoutTableSection::setLogicalPositionForCell(LayoutTableCell* cell, unsigned effectiveColumn) const
{
    LayoutPoint cellLocation(0, m_rowPos[cell->rowIndex()]);
    int horizontalBorderSpacing = table()->hBorderSpacing();

    // FIXME: The table's direction should determine our row's direction, not the section's (see bug 96691).
    if (!style()->isLeftToRightDirection())
        cellLocation.setX(LayoutUnit(table()->effectiveColumnPositions()[table()->numEffectiveColumns()] - table()->effectiveColumnPositions()[table()->absoluteColumnToEffectiveColumn(cell->absoluteColumnIndex() + cell->colSpan())] + horizontalBorderSpacing));
    else
        cellLocation.setX(LayoutUnit(table()->effectiveColumnPositions()[effectiveColumn] + horizontalBorderSpacing));

    cell->setLogicalLocation(cellLocation);
}

} // namespace blink