/*
* Copyright (C) 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "AccessibilityTable.h"
#include "AXObjectCache.h"
#include "AccessibilityTableCell.h"
#include "AccessibilityTableColumn.h"
#include "AccessibilityTableHeaderContainer.h"
#include "AccessibilityTableRow.h"
#include "HTMLNames.h"
#include "HTMLTableCaptionElement.h"
#include "HTMLTableCellElement.h"
#include "HTMLTableElement.h"
#include "RenderObject.h"
#include "RenderTable.h"
#include "RenderTableCell.h"
#include "RenderTableSection.h"
namespace WebCore {
using namespace HTMLNames;
AccessibilityTable::AccessibilityTable(RenderObject* renderer)
: AccessibilityRenderObject(renderer),
m_headerContainer(0)
{
#if ACCESSIBILITY_TABLES
m_isAccessibilityTable = isTableExposableThroughAccessibility();
#else
m_isAccessibilityTable = false;
#endif
}
AccessibilityTable::~AccessibilityTable()
{
}
PassRefPtr<AccessibilityTable> AccessibilityTable::create(RenderObject* renderer)
{
return adoptRef(new AccessibilityTable(renderer));
}
bool AccessibilityTable::hasARIARole() const
{
if (!m_renderer)
return false;
AccessibilityRole ariaRole = ariaRoleAttribute();
if (ariaRole != UnknownRole)
return true;
return false;
}
bool AccessibilityTable::isAccessibilityTable() const
{
if (!m_renderer)
return false;
return m_isAccessibilityTable;
}
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;
// 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);
Node* tableNode = table->node();
if (!tableNode || !tableNode->hasTagName(tableTag))
return false;
// if there is a caption element, summary, THEAD, or TFOOT section, it's most certainly a data table
HTMLTableElement* tableElement = static_cast<HTMLTableElement*>(tableNode);
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;
// 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
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;
// store the background color of the table to check against cell's background colors
RenderStyle* tableStyle = table->style();
if (!tableStyle)
return false;
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;
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;
Node* cellNode = cell->node();
if (!cellNode)
continue;
if (cell->width() < 1 || cell->height() < 1)
continue;
validCellCount++;
HTMLTableCellElement* cellElement = static_cast<HTMLTableCellElement*>(cellNode);
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++;
// If the first column is comprised of all <tg> tags, assume it is a data table.
if (!col && isTHCell)
headersInFirstColumnCount++;
// in this case, the developer explicitly assigned a "data" table attribute
if (!cellElement->headers().isEmpty() || !cellElement->abbr().isEmpty()
|| !cellElement->axis().isEmpty() || !cellElement->scope().isEmpty())
return true;
RenderStyle* renderStyle = cell->style();
if (!renderStyle)
continue;
// a cell needs to have matching bordered sides, before it can be considered a bordered cell.
if ((cell->borderTop() > 0 && cell->borderBottom() > 0)
|| (cell->borderLeft() > 0 && cell->borderRight() > 0))
borderedCellCount++;
// if the cell has a different color from the table and there is cell spacing,
// then it is probably a data table cell (spacing and colors take the place of borders)
Color cellColor = renderStyle->visitedDependentColor(CSSPropertyBackgroundColor);
if (table->hBorderSpacing() > 0 && table->vBorderSpacing() > 0
&& tableBGColor != cellColor && cellColor.alpha() != 1)
backgroundDifferenceCellCount++;
// if we've found 10 "good" cells, we don't need to keep searching
if (borderedCellCount >= 10 || backgroundDifferenceCellCount >= 10)
return true;
// For the first 5 rows, cache the background color so we can check if this table has zebra-striped rows.
if (row < 5 && row == alternatingRowColorCount) {
RenderObject* renderRow = cell->parent();
if (!renderRow || !renderRow->isBoxModelObject() || !toRenderBoxModelObject(renderRow)->isTableRow())
continue;
RenderStyle* rowRenderStyle = renderRow->style();
if (!rowRenderStyle)
continue;
Color rowColor = rowRenderStyle->visitedDependentColor(CSSPropertyBackgroundColor);
alternatingRowColors[alternatingRowColorCount] = rowColor;
alternatingRowColorCount++;
}
}
if (!row && headersInFirstRowCount == numCols && numCols > 1)
return true;
}
if (headersInFirstColumnCount == numRows && numRows > 1)
return true;
// if there is less than two valid cells, it's not a data table
if (validCellCount <= 1)
return false;
// half of the cells had borders, it's a data table
unsigned neededCellCount = validCellCount / 2;
if (borderedCellCount >= neededCellCount)
return true;
// half had different background colors, it's a data table
if (backgroundDifferenceCellCount >= neededCellCount)
return true;
// Check if there is an alternating row background color indicating a zebra striped style pattern.
if (alternatingRowColorCount > 2) {
Color firstColor = alternatingRowColors[0];
for (int k = 1; k < alternatingRowColorCount; k++) {
// If an odd row was the same color as the first row, its not alternating.
if (k % 2 == 1 && alternatingRowColors[k] == firstColor)
return false;
// If an even row is not the same as the first row, its not alternating.
if (!(k % 2) && alternatingRowColors[k] != firstColor)
return false;
}
return true;
}
return false;
}
bool AccessibilityTable::isTableExposableThroughAccessibility() const
{
// The following is a heuristic used to determine if a
// <table> should be exposed as an AXTable. The goal
// is to only show "data" tables.
if (!m_renderer)
return false;
// If the developer assigned an aria role to this, then we
// shouldn't expose it as a table, unless, of course, the aria
// role is a table.
if (hasARIARole())
return false;
// Gtk+ ATs expect all tables to be exposed as tables.
#if PLATFORM(GTK)
Node* tableNode = toRenderTable(m_renderer)->node();
return tableNode && tableNode->hasTagName(tableTag);
#endif
return isDataTable();
}
void AccessibilityTable::clearChildren()
{
AccessibilityRenderObject::clearChildren();
m_rows.clear();
m_columns.clear();
}
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
RenderTableSection* tableSection = table->header();
if (!tableSection)
tableSection = table->firstBody();
if (!tableSection)
return;
RenderTableSection* initialTableSection = tableSection;
while (tableSection) {
HashSet<AccessibilityObject*> appendedRows;
unsigned numRows = tableSection->numRows();
unsigned numCols = tableSection->numColumns();
for (unsigned rowIndex = 0; rowIndex < numRows; ++rowIndex) {
for (unsigned colIndex = 0; colIndex < numCols; ++colIndex) {
RenderTableCell* cell = tableSection->primaryCellAt(rowIndex, colIndex);
if (!cell)
continue;
AccessibilityObject* rowObject = axCache->getOrCreate(cell->parent());
if (!rowObject->isTableRow())
continue;
AccessibilityTableRow* row = static_cast<AccessibilityTableRow*>(rowObject);
// we need to check every cell for a new row, because cell spans
// can cause us to mess rows if we just check the first column
if (appendedRows.contains(row))
continue;
row->setRowIndex((int)m_rows.size());
m_rows.append(row);
if (!row->accessibilityIsIgnored())
m_children.append(row);
#if PLATFORM(GTK)
else
m_children.append(row->children());
#endif
appendedRows.add(row);
}
}
tableSection = table->sectionBelow(tableSection, true);
}
// make the columns based on the number of columns in the first body
unsigned length = initialTableSection->numColumns();
for (unsigned i = 0; i < length; ++i) {
AccessibilityTableColumn* column = static_cast<AccessibilityTableColumn*>(axCache->getOrCreate(ColumnRole));
column->setColumnIndex((int)i);
column->setParentTable(this);
m_columns.append(column);
if (!column->accessibilityIsIgnored())
m_children.append(column);
}
AccessibilityObject* headerContainerObject = headerContainer();
if (headerContainerObject && !headerContainerObject->accessibilityIsIgnored())
m_children.append(headerContainerObject);
}
AccessibilityObject* AccessibilityTable::headerContainer()
{
if (m_headerContainer)
return m_headerContainer;
m_headerContainer = static_cast<AccessibilityTableHeaderContainer*>(axObjectCache()->getOrCreate(TableHeaderContainerRole));
m_headerContainer->setParentTable(this);
return m_headerContainer;
}
AccessibilityObject::AccessibilityChildrenVector& AccessibilityTable::columns()
{
updateChildrenIfNecessary();
return m_columns;
}
AccessibilityObject::AccessibilityChildrenVector& AccessibilityTable::rows()
{
updateChildrenIfNecessary();
return m_rows;
}
void AccessibilityTable::rowHeaders(AccessibilityChildrenVector& headers)
{
if (!m_renderer)
return;
updateChildrenIfNecessary();
unsigned rowCount = m_rows.size();
for (unsigned k = 0; k < rowCount; ++k) {
AccessibilityObject* header = static_cast<AccessibilityTableRow*>(m_rows[k].get())->headerObject();
if (!header)
continue;
headers.append(header);
}
}
void AccessibilityTable::columnHeaders(AccessibilityChildrenVector& headers)
{
if (!m_renderer)
return;
updateChildrenIfNecessary();
unsigned colCount = m_columns.size();
for (unsigned k = 0; k < colCount; ++k) {
AccessibilityObject* header = static_cast<AccessibilityTableColumn*>(m_columns[k].get())->headerObject();
if (!header)
continue;
headers.append(header);
}
}
void AccessibilityTable::cells(AccessibilityObject::AccessibilityChildrenVector& cells)
{
if (!m_renderer)
return;
updateChildrenIfNecessary();
int numRows = m_rows.size();
for (int row = 0; row < numRows; ++row) {
AccessibilityChildrenVector rowChildren = m_rows[row]->children();
cells.append(rowChildren);
}
}
unsigned AccessibilityTable::columnCount()
{
updateChildrenIfNecessary();
return m_columns.size();
}
unsigned AccessibilityTable::rowCount()
{
updateChildrenIfNecessary();
return m_rows.size();
}
AccessibilityTableCell* AccessibilityTable::cellForColumnAndRow(unsigned column, unsigned row)
{
if (!m_renderer || !m_renderer->isTable())
return 0;
updateChildrenIfNecessary();
RenderTable* table = toRenderTable(m_renderer);
RenderTableSection* tableSection = table->header();
if (!tableSection)
tableSection = table->firstBody();
RenderTableCell* cell = 0;
unsigned rowCount = 0;
unsigned rowOffset = 0;
while (tableSection) {
unsigned numRows = tableSection->numRows();
unsigned numCols = tableSection->numColumns();
rowCount += numRows;
unsigned sectionSpecificRow = row - rowOffset;
if (row < rowCount && column < numCols && sectionSpecificRow < numRows) {
cell = tableSection->primaryCellAt(sectionSpecificRow, column);
// we didn't find the cell, which means there's spanning happening
// search backwards to find the spanning cell
if (!cell) {
// first try rows
for (int testRow = sectionSpecificRow-1; testRow >= 0; --testRow) {
cell = tableSection->primaryCellAt(testRow, column);
// cell overlapped. use this one
if (cell && ((cell->row() + (cell->rowSpan()-1)) >= (int)sectionSpecificRow))
break;
cell = 0;
}
if (!cell) {
// try cols
for (int testCol = column-1; testCol >= 0; --testCol) {
cell = tableSection->primaryCellAt(sectionSpecificRow, testCol);
// cell overlapped. use this one
if (cell && ((cell->col() + (cell->colSpan()-1)) >= (int)column))
break;
cell = 0;
}
}
}
}
if (cell)
break;
rowOffset += numRows;
// we didn't find anything between the rows we should have
if (row < rowCount)
break;
tableSection = table->sectionBelow(tableSection, true);
}
if (!cell)
return 0;
AccessibilityObject* cellObject = axObjectCache()->getOrCreate(cell);
ASSERT(cellObject->isTableCell());
return static_cast<AccessibilityTableCell*>(cellObject);
}
AccessibilityRole AccessibilityTable::roleValue() const
{
if (!isAccessibilityTable())
return AccessibilityRenderObject::roleValue();
return TableRole;
}
bool AccessibilityTable::accessibilityIsIgnored() const
{
AccessibilityObjectInclusion decision = accessibilityIsIgnoredBase();
if (decision == IncludeObject)
return false;
if (decision == IgnoreObject)
return true;
if (!isAccessibilityTable())
return AccessibilityRenderObject::accessibilityIsIgnored();
return false;
}
String AccessibilityTable::title() const
{
if (!isAccessibilityTable())
return AccessibilityRenderObject::title();
String title;
if (!m_renderer)
return title;
// see if there is a caption
Node* tableElement = m_renderer->node();
if (tableElement && tableElement->hasTagName(tableTag)) {
HTMLTableCaptionElement* caption = static_cast<HTMLTableElement*>(tableElement)->caption();
if (caption)
title = caption->innerText();
}
// try the standard
if (title.isEmpty())
title = AccessibilityRenderObject::title();
return title;
}
} // namespace WebCore