Cache QAccessibleInterfaces.

Since there already is a one-to-one relationship
between QObject and QAccessibleInterface it makes
little sense to create and destroy the interfaces
on each call to queryAccessibleInterface.

Add a cache and keep created interfaces around for
the lifetime of the corresponding QObject.

This changes the memory management rules: accessible
interfaces must no longer be deleted. If you get an
QAccessibleIntrface pointer that pointer will stay
valid as long as the corresponding QObject is not
deleted.

This also re-enables accessibility for Mac.

We limit the range of the IDs so that they are
useable for Windows directly.
That means we can get rid of the event cache there.

This is based on: Iebf2f374916fc70a9dd29e95f45a6444b85f6cee

Change-Id: I9fe6531812c0dbc5b41101ac05830a6dd75e13a3
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>

1 files changed, 70 insertions, 49 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
index df496a413b..1d6797e51a 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
@@ -47,48 +47,43 @@
 
 #import <AppKit/NSAccessibility.h>
 
-#ifndef QT_NO_COCOA_ACCESSIBILITY
-
-static QAccessibleInterface *acast(void *ptr)
-{
-    return reinterpret_cast<QAccessibleInterface *>(ptr);
-}
-
 @implementation QCocoaAccessibleElement
 
-- (id)initWithInterface:(void *)anQAccessibleInterface parent:(id)aParent
+- (id)initWithId:(QAccessible::Id)anId parent:(id)aParent
 {
+    Q_ASSERT((int)anId < 0);
     self = [super init];
     if (self) {
-        accessibleInterface = anQAccessibleInterface;
-        role = QCocoaAccessible::macRole(acast(accessibleInterface));
+        axid = anId;
+        QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+        Q_ASSERT(iface);
+        role = QCocoaAccessible::macRole(iface);
         parent = aParent;
     }
 
     return self;
 }
 
-+ (QCocoaAccessibleElement *)createElementWithInterface:(void *)anQAccessibleInterface parent:(id)aParent
++ (QCocoaAccessibleElement *)createElementWithId:(QAccessible::Id)anId parent:(id)aParent
 {
-    return [[self alloc] initWithInterface:anQAccessibleInterface parent:aParent];
+    return [[self alloc] initWithId:anId parent:aParent];
 }
 
 - (void)dealloc {
     [super dealloc];
-    delete acast(accessibleInterface);
 }
 
 - (BOOL)isEqual:(id)object {
     if ([object isKindOfClass:[QCocoaAccessibleElement class]]) {
         QCocoaAccessibleElement *other = object;
-        return acast(other->accessibleInterface)->object() == acast(accessibleInterface)->object();
+        return other->axid == axid;
     } else {
         return NO;
     }
 }
 
 - (NSUInteger)hash {
-    return qHash(acast(accessibleInterface)->object());
+    return axid;
 }
 
 //
@@ -99,6 +94,11 @@ static QAccessibleInterface *acast(void *ptr)
 
 - (NSArray *)accessibilityAttributeNames {
     static NSArray *defaultAttributes = nil;
+
+    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+    if (!iface)
+        return defaultAttributes;
+
     if (defaultAttributes == nil) {
         defaultAttributes = [[NSArray alloc] initWithObjects:
         NSAccessibilityRoleAttribute,
@@ -118,7 +118,7 @@ static QAccessibleInterface *acast(void *ptr)
     NSMutableArray *attributes = [[NSMutableArray alloc] initWithCapacity : [defaultAttributes count]];
     [attributes addObjectsFromArray : defaultAttributes];
 
-    if (QCocoaAccessible::hasValueAttribute(acast(accessibleInterface))) {
+    if (QCocoaAccessible::hasValueAttribute(iface)) {
         [attributes addObject : NSAccessibilityValueAttribute];
     }
 
@@ -126,22 +126,33 @@ static QAccessibleInterface *acast(void *ptr)
 }
 
 - (id)accessibilityAttributeValue:(NSString *)attribute {
+    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+    if (!iface) {
+        qWarning() << "Called attribute on invalid object: " << axid;
+        return nil;
+    }
+
     if ([attribute isEqualToString:NSAccessibilityRoleAttribute]) {
         return role;
     } else if ([attribute isEqualToString:NSAccessibilityRoleDescriptionAttribute]) {
         return NSAccessibilityRoleDescription(role, nil);
     } else if ([attribute isEqualToString:NSAccessibilityChildrenAttribute]) {
-        int numKids = acast(accessibleInterface)->childCount();
+
+        int numKids = iface->childCount();
+        // qDebug() << "Children for: " << axid << iface << " are: " << numKids;
 
         NSMutableArray *kids = [NSMutableArray arrayWithCapacity:numKids];
         for (int i = 0; i < numKids; ++i) {
-            QAccessibleInterface *childInterface = acast(accessibleInterface)->child(i);
-            QCocoaAccessibleElement *element = [QCocoaAccessibleElement createElementWithInterface:(void*)childInterface parent:self];
+            QAccessibleInterface *child = iface->child(i);
+            Q_ASSERT(child);
+            QAccessible::Id childId = QAccessible::uniqueId(child);
+            //qDebug() << "    kid: " << childId << child;
+            QCocoaAccessibleElement *element = [QCocoaAccessibleElement createElementWithId:childId parent:self];
             [kids addObject: element];
             [element release];
         }
-
         return kids;
+
     } else if ([attribute isEqualToString:NSAccessibilityFocusedAttribute]) {
         // Just check if the app thinks we're focused.
         id focusedElement = [NSApp accessibilityAttributeValue:NSAccessibilityFocusedUIElementAttribute];
@@ -155,23 +166,23 @@ static QAccessibleInterface *acast(void *ptr)
         // We're in the same top level element as our parent.
         return [parent accessibilityAttributeValue:NSAccessibilityTopLevelUIElementAttribute];
     } else if ([attribute isEqualToString:NSAccessibilityPositionAttribute]) {
-        QPoint qtPosition = acast(accessibleInterface)->rect().topLeft();
-        QSize qtSize = acast(accessibleInterface)->rect().size();
+        QPoint qtPosition = iface->rect().topLeft();
+        QSize qtSize = iface->rect().size();
         return [NSValue valueWithPoint: NSMakePoint(qtPosition.x(), qt_mac_flipYCoordinate(qtPosition.y() + qtSize.height()))];
     } else if ([attribute isEqualToString:NSAccessibilitySizeAttribute]) {
-        QSize qtSize = acast(accessibleInterface)->rect().size();
+        QSize qtSize = iface->rect().size();
         return [NSValue valueWithSize: NSMakeSize(qtSize.width(), qtSize.height())];
     } else if ([attribute isEqualToString:NSAccessibilityDescriptionAttribute]) {
-        return QCFString::toNSString(acast(accessibleInterface)->text(QAccessible::Name));
+        return QCFString::toNSString(iface->text(QAccessible::Name));
     } else if ([attribute isEqualToString:NSAccessibilityEnabledAttribute]) {
-        return [NSNumber numberWithBool:!acast(accessibleInterface)->state().disabled];
+        return [NSNumber numberWithBool:!iface->state().disabled];
     } else if ([attribute isEqualToString:NSAccessibilityValueAttribute]) {
         // VoiceOver asks for the value attribute for all elements. Return nil
         // if we don't want the element to have a value attribute.
-        if (!QCocoaAccessible::hasValueAttribute(acast(accessibleInterface)))
+        if (!QCocoaAccessible::hasValueAttribute(iface))
             return nil;
 
-        return QCocoaAccessible::getValueAttribute(acast(accessibleInterface));
+        return QCocoaAccessible::getValueAttribute(iface);
     }
 
     return nil;
@@ -196,8 +207,11 @@ static QAccessibleInterface *acast(void *ptr)
 
 - (NSArray *)accessibilityActionNames {
     NSMutableArray * nsActions = [NSMutableArray new];
+    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+    if (!iface)
+        return nsActions;
 
-    QAccessibleActionInterface *actionInterface = acast(accessibleInterface)->actionInterface();
+    QAccessibleActionInterface *actionInterface = iface->actionInterface();
     if (actionInterface) {
         QStringList supportedActionNames = actionInterface->actionNames();
 
@@ -212,48 +226,58 @@ static QAccessibleInterface *acast(void *ptr)
 }
 
 - (NSString *)accessibilityActionDescription:(NSString *)action {
-    QAccessibleActionInterface *actionInterface = acast(accessibleInterface)->actionInterface();
-    QString qtAction = QCocoaAccessible::translateAction(action);
+    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+    if (!iface)
+        return nil; // FIXME is that the right return type??
+    QAccessibleActionInterface *actionInterface = iface->actionInterface();
+    if (actionInterface) {
+        QString qtAction = QCocoaAccessible::translateAction(action);
 
-    // Return a description from the action interface if this action is not known to the OS.
-    if (qtAction.isEmpty()) {
-        QString description = actionInterface->localizedActionDescription(qtAction);
-        return QCFString::toNSString(description);
+        // Return a description from the action interface if this action is not known to the OS.
+        if (qtAction.isEmpty()) {
+            QString description = actionInterface->localizedActionDescription(qtAction);
+            return QCFString::toNSString(description);
+        }
     }
 
     return NSAccessibilityActionDescription(action);
 }
 
 - (void)accessibilityPerformAction:(NSString *)action {
-    QAccessibleActionInterface *actionInterface = acast(accessibleInterface)->actionInterface();
-    if (actionInterface) {
-        actionInterface->doAction(QCocoaAccessible::translateAction(action));
+    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+    if (iface) {
+        QAccessibleActionInterface *actionInterface = iface->actionInterface();
+        if (actionInterface) {
+            actionInterface->doAction(QCocoaAccessible::translateAction(action));
+        }
     }
 }
 
 // misc
 
 - (BOOL)accessibilityIsIgnored {
-    return QCocoaAccessible::shouldBeIgnrored(acast(accessibleInterface));
+    return false; //QCocoaAccessible::shouldBeIgnored(QAccessible::accessibleInterface(id));
 }
 
 - (id)accessibilityHitTest:(NSPoint)point {
-
-    if (!accessibleInterface)
-        return NSAccessibilityUnignoredAncestor(self);
-
-    if (!acast(accessibleInterface)->isValid())
+    QAccessibleInterface *iface = QAccessible::accessibleInterface(axid);
+    if (!iface || !iface->isValid()) {
+//        qDebug() << "Hit test: INVALID";
         return NSAccessibilityUnignoredAncestor(self);
+    }
 
-    QAccessibleInterface *childInterface = acast(accessibleInterface)->childAt(point.x, qt_mac_flipYCoordinate(point.y));
+    QAccessibleInterface *childInterface = iface->childAt(point.x, qt_mac_flipYCoordinate(point.y));
 
     // No child found, meaning we hit this element.
     if (!childInterface) {
-        return NSAccessibilityUnignoredAncestor(self);
+//        qDebug() << "Hit test returns: " << id << iface;
+        return self;
+        //return NSAccessibilityUnignoredAncestor(self);
     }
 
+    QAccessible::Id childId = QAccessible::uniqueId(childInterface);
     // hit a child, forward to child accessible interface.
-    QCocoaAccessibleElement *accessibleElement = [QCocoaAccessibleElement createElementWithInterface:childInterface parent:self];
+    QCocoaAccessibleElement *accessibleElement = [QCocoaAccessibleElement createElementWithId:childId parent:self];
     [accessibleElement autorelease];
 
     return [accessibleElement accessibilityHitTest:point];
@@ -264,6 +288,3 @@ static QAccessibleInterface *acast(void *ptr)
 }
 
 @end
-
-#endif // QT_NO_COCOA_ACCESSIBILITY
-