macOS Accessibility: optimize table interface implementation

Store row and column in the QMacAccessibilityElement when creating it so
that we can avoid linearly looking for ourselves in the parent's data.

Row elements have their m_rowIndex set, Column elements the
m_columnIndex, and elements representing a cell have both set. Cells
are not managed by the table.

Task-number: QTBUG-34337
Pick-to: 6.5
Change-Id: I319fad1f1fda0cfa4c0b95e9e16c25c87df04351
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

2 files changed, 58 insertions, 44 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibility.mm b/src/plugins/platforms/cocoa/qcocoaaccessibility.mm
index dc2baa6961..69ec52afe7 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibility.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibility.mm
@@ -117,7 +117,6 @@ static void populateRoleMap()
     roleMap[QAccessible::ColumnHeader] = NSAccessibilityColumnRole;
     roleMap[QAccessible::Row] = NSAccessibilityRowRole;
     roleMap[QAccessible::RowHeader] = NSAccessibilityRowRole;
-    roleMap[QAccessible::Cell] = NSAccessibilityTextFieldRole;
     roleMap[QAccessible::Button] = NSAccessibilityButtonRole;
     roleMap[QAccessible::EditableText] = NSAccessibilityTextFieldRole;
     roleMap[QAccessible::Link] = NSAccessibilityLinkRole;
@@ -125,7 +124,7 @@ static void populateRoleMap()
     roleMap[QAccessible::Splitter] = NSAccessibilitySplitGroupRole;
     roleMap[QAccessible::List] = NSAccessibilityListRole;
     roleMap[QAccessible::ListItem] = NSAccessibilityStaticTextRole;
-    roleMap[QAccessible::Cell] = NSAccessibilityStaticTextRole;
+    roleMap[QAccessible::Cell] = NSAccessibilityCellRole;
     roleMap[QAccessible::Client] = NSAccessibilityGroupRole;
     roleMap[QAccessible::Paragraph] = NSAccessibilityGroupRole;
     roleMap[QAccessible::Section] = NSAccessibilityGroupRole;
diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
index fcc149c981..705342b1ea 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
@@ -80,6 +80,8 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
 
 @implementation QMacAccessibilityElement {
     QAccessible::Id axid;
+    int m_rowIndex;
+    int m_columnIndex;
 
     // used by NSAccessibilityTable
     NSMutableArray<QMacAccessibilityElement *> *rows;       // corresponds to accessibilityRows
@@ -105,12 +107,25 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
     self = [super init];
     if (self) {
         axid = anId;
+        m_rowIndex = -1;
+        m_columnIndex = -1;
         rows = nil;
         columns = nil;
         synthesizedRole = role;
-        QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
-        if (iface && iface->tableInterface() && !synthesizedRole)
-            [self updateTableModel];
+        // table: if this is not created as an element managed by the table, then
+        // it's either the table itself, or an element created for an already existing
+        // cell interface (or an element that's not at all related to a table).
+        if (!synthesizedRole) {
+            if (QAccessibleInterface *iface = QAccessible::accessibleInterface(axid)) {
+                if (iface->tableInterface()) {
+                    [self updateTableModel];
+                } else if (const auto *cell = iface->tableCellInterface()) {
+                    // if we create an element for a table cell, initialize it with row/column
+                    m_rowIndex = cell->rowIndex();
+                    m_columnIndex = cell->columnIndex();
+                }
+            }
+        }
     }
 
     return self;
@@ -183,6 +198,10 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
             QMacAccessibilityElement *element =
                     [[QMacAccessibilityElement alloc] initWithId:axid role:role];
             if (element) {
+                if (role == NSAccessibilityRowRole)
+                    element->m_rowIndex = n;
+                else if (role == NSAccessibilityColumnRole)
+                    element->m_columnIndex = n;
                 [array addObject:element];
                 [element release];
             } else {
@@ -320,25 +339,26 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
         } else if (synthesizedRole == NSAccessibilityRowRole) {
             // axid matches the parent table axid so that we can easily find the parent table
             // children of row are cell/any items
-            QMacAccessibilityElement *tableElement = [QMacAccessibilityElement elementWithId:axid];
-            Q_ASSERT(tableElement->rows);
-            NSUInteger rowIndex = [tableElement->rows indexOfObjectIdenticalTo:self];
-            Q_ASSERT(rowIndex != NSNotFound);
-            int numColumns = table->columnCount();
-            NSMutableArray<QMacAccessibilityElement *> *cells =
-                    [NSMutableArray<QMacAccessibilityElement *> arrayWithCapacity:numColumns];
-            for (int i = 0; i < numColumns; ++i) {
-                QAccessibleInterface *cell = table->cellAt(rowIndex, i);
-                if (cell && cell->isValid()) {
-                    QAccessible::Id cellId = QAccessible::uniqueId(cell);
-                    QMacAccessibilityElement *element =
-                            [QMacAccessibilityElement elementWithId:cellId];
-                    if (element) {
-                        [cells addObject:element];
+            Q_ASSERT(m_rowIndex >= 0);
+            if (!columns) {
+                const int numColumns = table->columnCount();
+                columns = [NSMutableArray<QMacAccessibilityElement *> arrayWithCapacity:numColumns];
+                for (int i = 0; i < numColumns; ++i) {
+                    QAccessibleInterface *cell = table->cellAt(m_rowIndex, i);
+                    if (cell && cell->isValid()) {
+                        QAccessible::Id cellId = QAccessible::uniqueId(cell);
+                        QMacAccessibilityElement *element =
+                                [QMacAccessibilityElement elementWithId:cellId];
+                        if (element) {
+                            element->m_rowIndex = m_rowIndex;
+                            element->m_columnIndex = i;
+                            [columns insertObject:element atIndex:i];
+                        }
                     }
                 }
+                [columns retain];
             }
-            return NSAccessibilityUnignoredChildren(cells);
+            return NSAccessibilityUnignoredChildren(columns);
         }
     }
     return QCocoaAccessible::unignoredChildren(iface);
@@ -388,18 +408,19 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
 
     if (QAccessibleInterface *parent = iface->parent()) {
         if (parent->tableInterface()) {
-            if (QAccessibleTableCellInterface *cell = iface->tableCellInterface()) {
-                // parent of cell should be row
-                QAccessible::Id parentId = QAccessible::uniqueId(parent);
-                QMacAccessibilityElement *tableElement =
-                        [QMacAccessibilityElement elementWithId:parentId];
-
-                const int rowIndex = cell->rowIndex();
-                if (tableElement->rows && int([tableElement->rows count]) > rowIndex) {
-                    QMacAccessibilityElement *rowElement = tableElement->rows[rowIndex];
-                    return NSAccessibilityUnignoredAncestor(rowElement);
-                }
-            }
+            QAccessible::Id parentId = QAccessible::uniqueId(parent);
+            QMacAccessibilityElement *tableElement =
+                    [QMacAccessibilityElement elementWithId:parentId];
+
+            // parent of cell should be row
+            int rowIndex = -1;
+            if (m_rowIndex >= 0 && m_columnIndex >= 0)
+                rowIndex = m_rowIndex;
+            else if (QAccessibleTableCellInterface *cell = iface->tableCellInterface())
+                rowIndex = cell->rowIndex();
+            Q_ASSERT(tableElement->rows && int([tableElement->rows count]) > rowIndex);
+            QMacAccessibilityElement *rowElement = tableElement->rows[rowIndex];
+            return NSAccessibilityUnignoredAncestor(rowElement);
         }
         if (parent->role() != QAccessible::Application) {
             QAccessible::Id parentId = QAccessible::uniqueId(parent);
@@ -436,10 +457,7 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
             int &row = isRow ? cellPos.ry() : cellPos.rx();
             int &col = isRow ? cellPos.rx() : cellPos.ry();
 
-            QMacAccessibilityElement *tableElement =
-                    [QMacAccessibilityElement elementWithId:axid];
-            NSArray *tracks = isRow ? tableElement->rows : tableElement->columns;
-            NSUInteger trackIndex = [tracks indexOfObjectIdenticalTo:self];
+            NSUInteger trackIndex = self.accessibilityIndex;
             if (trackIndex != NSNotFound) {
                 row = int(trackIndex);
                 if (QAccessibleInterface *firstCell = table->cellAt(cellPos.y(), cellPos.x())) {
@@ -808,13 +826,10 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
             // axid matches the parent table axid so that we can easily find the parent table
             // children of row are cell/any items
             if (QAccessibleTableInterface *table = iface->tableInterface()) {
-                QMacAccessibilityElement *tableElement = [QMacAccessibilityElement elementWithId:axid];
-                NSArray *track = synthesizedRole == NSAccessibilityRowRole
-                               ? tableElement->rows : tableElement->columns;
-                if (track) {
-                    NSUInteger trackIndex = [track indexOfObjectIdenticalTo:self];
-                    index = (NSInteger)trackIndex;
-                }
+                if (m_rowIndex >= 0)
+                    index = NSInteger(m_rowIndex);
+                else if (m_columnIndex >= 0)
+                    index = NSInteger(m_columnIndex);
             }
         }
     }