C++ RenderTable::recalcSectionsIfNeeded方法代码示例

void RenderTableCol::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBox::styleDidChange(diff, oldStyle);

    // If border was changed, notify table.
    if (parent()) {
        RenderTable* table = this->table();
        if (table && !table->selfNeedsLayout() && !table->normalChildNeedsLayout() && oldStyle && oldStyle->border() != style().border())
            table->invalidateCollapsedBorders();
        else if (oldStyle->width() != style().width()) {
            table->recalcSectionsIfNeeded();
            for (auto& section : childrenOfType<RenderTableSection>(*table)) {
                unsigned nEffCols = table->numEffCols();
                for (unsigned j = 0; j < nEffCols; j++) {
                    unsigned rowCount = section.numRows();
                    for (unsigned i = 0; i < rowCount; i++) {
                        RenderTableCell* cell = section.primaryCellAt(i, j);
                        if (!cell)
                            continue;
                        cell->setPreferredLogicalWidthsDirty(true);
                    }
                }
            }
        }
    }
}

void AccessibilityTable::addChildren()
{
    if (!isAccessibilityTable()) {
        AccessibilityRenderObject::addChildren();
        return;
    }
    
    ASSERT(!m_haveChildren); 
    
    m_haveChildren = true;
    if (!m_renderer || !m_renderer->isTable())
        return;
    
    RenderTable* table = toRenderTable(m_renderer);
    // Go through all the available sections to pull out the rows and add them as children.
    table->recalcSectionsIfNeeded();
    
    unsigned maxColumnCount = 0;
    RenderTableSection* footer = table->footer();
    
    for (RenderTableSection* tableSection = table->topSection(); tableSection; tableSection = table->sectionBelow(tableSection, SkipEmptySections)) {
        if (tableSection == footer)
            continue;
        addChildrenFromSection(tableSection, maxColumnCount);
    }
    
    // Process the footer last, in case it was ordered earlier in the DOM.
    if (footer)
        addChildrenFromSection(footer, maxColumnCount);
    
    AXObjectCache* axCache = m_renderer->document().axObjectCache();
    // make the columns based on the number of columns in the first body
    unsigned length = maxColumnCount;
    for (unsigned i = 0; i < length; ++i) {
        AccessibilityTableColumn* column = toAccessibilityTableColumn(axCache->getOrCreate(ColumnRole));
        column->setColumnIndex((int)i);
        column->setParent(this);
        m_columns.append(column);
        if (!column->accessibilityIsIgnored())
            m_children.append(column);
    }
    
    AccessibilityObject* headerContainerObject = headerContainer();
    if (headerContainerObject && !headerContainerObject->accessibilityIsIgnored())
        m_children.append(headerContainerObject);
}

bool AccessibilityTable::isDataTable() const
{
    if (!m_renderer)
        return false;

    // Do not consider it a data table is it has an ARIA role.
    if (hasARIARole())
        return false;

    // When a section of the document is contentEditable, all tables should be
    // treated as data tables, otherwise users may not be able to work with rich
    // text editors that allow creating and editing tables.
    if (node() && node()->hasEditableStyle())
        return true;

    // This employs a heuristic to determine if this table should appear.
    // Only "data" tables should be exposed as tables.
    // Unfortunately, there is no good way to determine the difference
    // between a "layout" table and a "data" table.
    
    RenderTable* table = toRenderTable(m_renderer);
    if (!table->element() || !isHTMLTableElement(table->element()))
        return false;

    // if there is a caption element, summary, THEAD, or TFOOT section, it's most certainly a data table
    HTMLTableElement* tableElement = toHTMLTableElement(table->element());
    if (!tableElement->summary().isEmpty() || tableElement->tHead() || tableElement->tFoot() || tableElement->caption())
        return true;
    
    // if someone used "rules" attribute than the table should appear
    if (!tableElement->rules().isEmpty())
        return true;    

    // if there's a colgroup or col element, it's probably a data table.
    for (const auto& child : childrenOfType<Element>(*tableElement)) {
        if (child.hasTagName(colTag) || child.hasTagName(colgroupTag))
            return true;
    }
    
    // go through the cell's and check for tell-tale signs of "data" table status
    // cells have borders, or use attributes like headers, abbr, scope or axis
    table->recalcSectionsIfNeeded();
    RenderTableSection* firstBody = table->firstBody();
    if (!firstBody)
        return false;
    
    int numCols = firstBody->numColumns();
    int numRows = firstBody->numRows();
    
    // If there's only one cell, it's not a good AXTable candidate.
    if (numRows == 1 && numCols == 1)
        return false;

    // If there are at least 20 rows, we'll call it a data table.
    if (numRows >= 20)
        return true;
    
    // Store the background color of the table to check against cell's background colors.
    const RenderStyle& tableStyle = table->style();
    Color tableBGColor = tableStyle.visitedDependentColor(CSSPropertyBackgroundColor);
    
    // check enough of the cells to find if the table matches our criteria
    // Criteria: 
    //   1) must have at least one valid cell (and)
    //   2) at least half of cells have borders (or)
    //   3) at least half of cells have different bg colors than the table, and there is cell spacing
    unsigned validCellCount = 0;
    unsigned borderedCellCount = 0;
    unsigned backgroundDifferenceCellCount = 0;
    unsigned cellsWithTopBorder = 0;
    unsigned cellsWithBottomBorder = 0;
    unsigned cellsWithLeftBorder = 0;
    unsigned cellsWithRightBorder = 0;
    
    Color alternatingRowColors[5];
    int alternatingRowColorCount = 0;
    
    int headersInFirstColumnCount = 0;
    for (int row = 0; row < numRows; ++row) {
    
        int headersInFirstRowCount = 0;
        for (int col = 0; col < numCols; ++col) {    
            RenderTableCell* cell = firstBody->primaryCellAt(row, col);
            if (!cell)
                continue;

            Element* cellElement = cell->element();
            if (!cellElement)
                continue;
            
            if (cell->width() < 1 || cell->height() < 1)
                continue;
            
            validCellCount++;
            
            bool isTHCell = cellElement->hasTagName(thTag);
            // If the first row is comprised of all <th> tags, assume it is a data table.
            if (!row && isTHCell)
                headersInFirstRowCount++;

//.........这里部分代码省略.........

void AccessibilityTable::addChildren()
{
    if (!isAccessibilityTable()) {
        AccessibilityRenderObject::addChildren();
        return;
    }
    
    ASSERT(!m_haveChildren); 
    
    m_haveChildren = true;
    if (!m_renderer || !m_renderer->isTable())
        return;
    
    RenderTable* table = toRenderTable(m_renderer);
    AXObjectCache* axCache = m_renderer->document().axObjectCache();

    // Go through all the available sections to pull out the rows and add them as children.
    table->recalcSectionsIfNeeded();
    RenderTableSection* tableSection = table->topSection();
    if (!tableSection)
        return;
    
    unsigned maxColumnCount = 0;
    while (tableSection) {
        
        HashSet<AccessibilityObject*> appendedRows;
        unsigned numRows = tableSection->numRows();
        for (unsigned rowIndex = 0; rowIndex < numRows; ++rowIndex) {
            
            RenderTableRow* renderRow = tableSection->rowRendererAt(rowIndex);
            if (!renderRow)
                continue;
            
            AccessibilityObject* rowObject = axCache->getOrCreate(renderRow);
            if (!rowObject->isTableRow())
                continue;
            
            AccessibilityTableRow* row = toAccessibilityTableRow(rowObject);
            // We need to check every cell for a new row, because cell spans
            // can cause us to miss rows if we just check the first column.
            if (appendedRows.contains(row))
                continue;
            
            row->setRowIndex(static_cast<int>(m_rows.size()));
            m_rows.append(row);
            if (!row->accessibilityIsIgnored())
                m_children.append(row);
#if PLATFORM(GTK) || PLATFORM(EFL)
            else
                m_children.appendVector(row->children());
#endif
            appendedRows.add(row);
        }
    
        maxColumnCount = std::max(tableSection->numColumns(), maxColumnCount);
        tableSection = table->sectionBelow(tableSection, SkipEmptySections);
    }
    
    // make the columns based on the number of columns in the first body
    unsigned length = maxColumnCount;
    for (unsigned i = 0; i < length; ++i) {
        AccessibilityTableColumn* column = toAccessibilityTableColumn(axCache->getOrCreate(ColumnRole));
        column->setColumnIndex((int)i);
        column->setParent(this);
        m_columns.append(column);
        if (!column->accessibilityIsIgnored())
            m_children.append(column);
    }
    
    AccessibilityObject* headerContainerObject = headerContainer();
    if (headerContainerObject && !headerContainerObject->accessibilityIsIgnored())
        m_children.append(headerContainerObject);
}