macOS: Don't include two windows in a11y tree. (AvaloniaUI#15899)

* Don't include two windows in a11y tree.

`AvnRootAccessibilityElement` has been removed and now `AvnWindow` handles the accessibility protocol itself, exposing its children via the `AvnView`.

* Remove hack now that issue is fixed.

* Fix build errors after merge.

native/Avalonia.Native/src/OSX/Avalonia.Native.OSX.xcodeproj/project.pbxproj

@@ -57,6 +57,7 @@
 		AB8F7D6B21482D7F0057DBA5 /* platformthreading.mm in Sources */ = {isa = PBXBuildFile; fileRef = AB8F7D6A21482D7F0057DBA5 /* platformthreading.mm */; };
 		BC11A5BE2608D58F0017BAD0 /* automation.h in Headers */ = {isa = PBXBuildFile; fileRef = BC11A5BC2608D58F0017BAD0 /* automation.h */; };
 		BC11A5BF2608D58F0017BAD0 /* automation.mm in Sources */ = {isa = PBXBuildFile; fileRef = BC11A5BD2608D58F0017BAD0 /* automation.mm */; };
+		BC7C33822C066DBF00945A48 /* AvnAutomationNode.h in Headers */ = {isa = PBXBuildFile; fileRef = BC7C33812C066DBF00945A48 /* AvnAutomationNode.h */; };
 		ED3791C42862E1F40080BD62 /* UniformTypeIdentifiers.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = ED3791C32862E1F40080BD62 /* UniformTypeIdentifiers.framework */; };
 		ED754D262A97306B0078B4DF /* PlatformRenderTimer.mm in Sources */ = {isa = PBXBuildFile; fileRef = ED754D252A97306B0078B4DF /* PlatformRenderTimer.mm */; };
 		EDF8CDCD2964CB01001EE34F /* PlatformSettings.mm in Sources */ = {isa = PBXBuildFile; fileRef = EDF8CDCC2964CB01001EE34F /* PlatformSettings.mm */; };
@@ -122,6 +123,8 @@
 		AB8F7D6A21482D7F0057DBA5 /* platformthreading.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = platformthreading.mm; sourceTree = "<group>"; };
 		BC11A5BC2608D58F0017BAD0 /* automation.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = automation.h; sourceTree = "<group>"; };
 		BC11A5BD2608D58F0017BAD0 /* automation.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = automation.mm; sourceTree = "<group>"; };
+		BC7C33812C066DBF00945A48 /* AvnAutomationNode.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AvnAutomationNode.h; sourceTree = "<group>"; };
+		BC7C33832C066F1100945A48 /* AvnAccessibility.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = AvnAccessibility.h; sourceTree = "<group>"; };
 		ED3791C32862E1F40080BD62 /* UniformTypeIdentifiers.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UniformTypeIdentifiers.framework; path = System/Library/Frameworks/UniformTypeIdentifiers.framework; sourceTree = SDKROOT; };
 		ED754D252A97306B0078B4DF /* PlatformRenderTimer.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = PlatformRenderTimer.mm; sourceTree = "<group>"; };
 		EDF8CDCC2964CB01001EE34F /* PlatformSettings.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = PlatformSettings.mm; sourceTree = "<group>"; };
@@ -167,6 +170,8 @@
 			isa = PBXGroup;
 			children = (
 				F10084852BFF1FB40024303E /* TopLevelImpl.mm */,
+				BC7C33832C066F1100945A48 /* AvnAccessibility.h */,
+				BC7C33812C066DBF00945A48 /* AvnAutomationNode.h */,
 				ED754D252A97306B0078B4DF /* PlatformRenderTimer.mm */,
 				855EDC9E28C6546F00807998 /* PlatformBehaviorInhibition.mm */,
 				8D2F3511292F6AAE007FCF54 /* AvnTextInputMethodDelegate.h */,
@@ -245,6 +250,7 @@
 				183916173528EC2737DBE5E1 /* WindowBaseImpl.h in Headers */,
 				1839171DCC651B0638603AC4 /* INSWindowHolder.h in Headers */,
 				183919D91DB9AAB5D700C2EA /* WindowImpl.h in Headers */,
+				BC7C33822C066DBF00945A48 /* AvnAutomationNode.h in Headers */,
 				18391CF07316F819E76B617C /* IWindowStateChanged.h in Headers */,
 				8D300D65292D0A6800320C49 /* AvnTextInputMethod.h in Headers */,
 				8D2F3512292F6AAE007FCF54 /* AvnTextInputMethodDelegate.h in Headers */,

native/Avalonia.Native/src/OSX/AvnAccessibility.h

@@ -0,0 +1,13 @@
+#pragma once
+#import <Cocoa/Cocoa.h>
+#import "avalonia-native.h"
+
+// Defines the interface between AvnAutomationNode and objects which implement
+// NSAccessibility such as AvnAccessibilityElement or AvnWindow.
+@protocol AvnAccessibility <NSAccessibility>
+@required
+- (void) raiseChildrenChanged;
+@optional
+- (void) raiseFocusChanged;
+- (void) raisePropertyChanged:(AvnAutomationProperty)property;
+@end

native/Avalonia.Native/src/OSX/AvnAutomationNode.h

@@ -0,0 +1,18 @@
+#pragma once
+#include "avalonia-native.h"
+#include "AvnAccessibility.h"
+
+// Defines a means for managed code to raise accessibility events.
+class AvnAutomationNode : public ComSingleObject<IAvnAutomationNode, &IID_IAvnAutomationNode>
+{
+public:
+    FORWARD_IUNKNOWN()
+    AvnAutomationNode(id <AvnAccessibility> owner) { _owner = owner; }
+    AvnAccessibilityElement* GetOwner() { return _owner; }
+    virtual void Dispose() override { _owner = nil; }
+    virtual void ChildrenChanged () override { [_owner raiseChildrenChanged]; }
+    virtual void PropertyChanged (AvnAutomationProperty property) override { [_owner raisePropertyChanged:property]; }
+    virtual void FocusChanged () override { [_owner raiseFocusChanged]; }
+private:
+    __strong id <AvnAccessibility> _owner;
+};

native/Avalonia.Native/src/OSX/AvnView.h

@@ -22,5 +22,6 @@
 -(AvnPlatformResizeReason) getResizeReason;
 -(void) setResizeReason:(AvnPlatformResizeReason)reason;
 -(void) setRenderTarget:(NSObject<IRenderTarget>* _Nonnull)target;
+-(void) raiseAccessibilityChildrenChanged;
 + (AvnPoint)toAvnPoint:(CGPoint)p;
 @end

native/Avalonia.Native/src/OSX/AvnView.mm

@@ -19,12 +19,12 @@ @implementation AvnView
     AvnPixelSize _lastPixelSize;
     NSObject<IRenderTarget>* _currentRenderTarget;
     AvnPlatformResizeReason _resizeReason;
-    AvnAccessibilityElement* _accessibilityChild;
     NSRect _cursorRect;
     NSMutableAttributedString* _text;
     NSRange _selectedRange;
     NSRange _markedRange;
     NSEvent* _lastKeyDownEvent;
+    NSMutableArray* _accessibilityChildren;
 }
 
 - (void)onClosed
@@ -801,35 +801,74 @@ - (void)setResizeReason:(AvnPlatformResizeReason)reason
     _resizeReason = reason;
 }
 
-- (AvnAccessibilityElement *) accessibilityChild
+- (NSArray *)accessibilityChildren
 {
-    if (_accessibilityChild == nil)
-    {
-        auto peer = _parent->TopLevelEvents->GetAutomationPeer();
+    if (_accessibilityChildren == nil)
+        [self recalculateAccessibiltyChildren];
+    return _accessibilityChildren;
+}
 
-        if (peer == nil)
-            return nil;
+- (id _Nullable) accessibilityHitTest:(NSPoint)point
+{
+    if (![[self window] isKindOfClass:[AvnWindow class]])
+        return self;
 
-        _accessibilityChild = [AvnAccessibilityElement acquire:peer];
-    }
+    auto window = (AvnWindow*)[self window];
+    auto peer = [window automationPeer];
 
-    return _accessibilityChild;
-}
+    if (!peer->IsRootProvider())
+        return nil;
 
-- (NSArray *)accessibilityChildren
-{
-    auto child = [self accessibilityChild];
-    return NSAccessibilityUnignoredChildrenForOnlyChild(child);
+    auto clientPoint = [window convertPointFromScreen:point];
+    auto localPoint = [self translateLocalPoint:ToAvnPoint(clientPoint)];
+    auto hit = peer->RootProvider_GetPeerFromPoint(localPoint);
+    return [AvnAccessibilityElement acquire:hit];
 }
 
-- (id)accessibilityHitTest:(NSPoint)point
+- (void)raiseAccessibilityChildrenChanged
 {
-    return [[self accessibilityChild] accessibilityHitTest:point];
+    auto changed = _accessibilityChildren ? [NSMutableSet setWithArray:_accessibilityChildren] : [NSMutableSet set];
+
+    [self recalculateAccessibiltyChildren];
+
+    if (_accessibilityChildren)
+        [changed addObjectsFromArray:_accessibilityChildren];
+
+    NSAccessibilityPostNotificationWithUserInfo(
+        self,
+        NSAccessibilityLayoutChangedNotification,
+        @{ NSAccessibilityUIElementsKey: [changed allObjects]});
 }
 
-- (id)accessibilityFocusedUIElement
+- (void)recalculateAccessibiltyChildren
 {
-    return [[self accessibilityChild] accessibilityFocusedUIElement];
+    _accessibilityChildren = [[NSMutableArray alloc] init];
+
+    if (![[self window] isKindOfClass:[AvnWindow class]])
+    {
+        return;
+    }
+
+    // The accessibility children of the Window are exposed as children
+    // of the AvnView.
+    auto window = (AvnWindow*)[self window];
+    auto peer = [window automationPeer];
+    auto childPeers = peer->GetChildren();
+    auto childCount = childPeers != nullptr ? childPeers->GetCount() : 0;
+
+    if (childCount > 0)
+    {
+        for (int i = 0; i < childCount; ++i)
+        {
+            IAvnAutomationPeer* child;
+
+            if (childPeers->Get(i, &child) == S_OK)
+            {
+                id element = [AvnAccessibilityElement acquire:child];
+                [_accessibilityChildren addObject:element];
+            }
+        }
+    }
 }
 
 - (void) setText:(NSString *)text{

native/Avalonia.Native/src/OSX/AvnWindow.mm

@@ -24,6 +24,8 @@
 #include "WindowImpl.h"
 #include "AvnView.h"
 #include "WindowInterfaces.h"
+#include "AvnAutomationNode.h"
+#include "AvnString.h"
 
 @implementation CLASS_NAME
 {
@@ -34,6 +36,13 @@ @implementation CLASS_NAME
     bool _isExtended;
     bool _isTransitioningToFullScreen;
     AvnMenu* _menu;
+    IAvnAutomationPeer* _automationPeer;
+    AvnAutomationNode* _automationNode;
+}
+
+-(AvnView* _Nullable) view
+{
+    return _parent->View;
 }
 
 -(void) setIsExtended:(bool)value;
@@ -208,7 +217,7 @@ - (void)windowWillClose:(NSNotification *_Nonnull)notification
         ComPtr<WindowBaseImpl> parent = _parent;
         _parent = NULL;
 
-        auto window = dynamic_cast<WindowImpl*>(parent.getRaw());
+            auto window = dynamic_cast<WindowImpl*>(parent.getRaw());
 
         if(window != nullptr)
         {
@@ -489,5 +498,41 @@ - (void)disconnectParent {
     _parent = nullptr;
 }
 
+- (id _Nullable) accessibilityFocusedUIElement
+{
+    if (![self automationPeer]->IsRootProvider())
+        return nil;
+    auto focusedPeer = [self automationPeer]->RootProvider_GetFocus();
+    return [AvnAccessibilityElement acquire:focusedPeer];
+}
+
+- (NSString * _Nullable) accessibilityIdentifier
+{
+    return GetNSStringAndRelease([self automationPeer]->GetAutomationId());
+}
+
+- (IAvnAutomationPeer* _Nonnull) automationPeer
+{
+    if (_automationPeer == nullptr)
+    {
+        _automationPeer = _parent->BaseEvents->GetAutomationPeer();
+        _automationNode = new AvnAutomationNode(self);
+        _automationPeer->SetNode(_automationNode);
+    }
+
+    return _automationPeer;
+}
+
+- (void)raiseChildrenChanged
+{
+    [_parent->View raiseAccessibilityChildrenChanged];
+}
+
+- (void)raiseFocusChanged
+{
+    id focused = [self accessibilityFocusedUIElement];
+    NSAccessibilityPostNotification(focused, NSAccessibilityFocusedUIElementChangedNotification);
+}
+
 @end
 

native/Avalonia.Native/src/OSX/WindowInterfaces.h

@@ -7,11 +7,13 @@
 #import <AppKit/AppKit.h>
 #include "WindowProtocol.h"
 #include "WindowBaseImpl.h"
+#include "AvnAccessibility.h"
 
-@interface AvnWindow : NSWindow <AvnWindowProtocol, NSWindowDelegate>
+@interface AvnWindow : NSWindow <AvnWindowProtocol, NSWindowDelegate, AvnAccessibility>
 -(AvnWindow* _Nonnull) initWithParent: (WindowBaseImpl* _Nonnull) parent contentRect: (NSRect)contentRect styleMask: (NSWindowStyleMask)styleMask;
+-(AvnView* _Nullable) view;
 @end
 
-@interface AvnPanel : NSPanel <AvnWindowProtocol, NSWindowDelegate>
+@interface AvnPanel : NSPanel <AvnWindowProtocol, NSWindowDelegate, AvnAccessibility>
 -(AvnPanel* _Nonnull) initWithParent: (WindowBaseImpl* _Nonnull) parent contentRect: (NSRect)contentRect styleMask: (NSWindowStyleMask)styleMask;
-@end
+@end

native/Avalonia.Native/src/OSX/WindowProtocol.h

@@ -8,6 +8,7 @@
 #import <AppKit/AppKit.h>
 
 @class AvnMenu;
+struct IAvnAutomationPeer;
 
 @protocol AvnWindowProtocol
 -(void) pollModalSession: (NSModalSession _Nonnull) session;
@@ -16,6 +17,7 @@
 -(void) showAppMenuOnly;
 -(void) showWindowMenuWithAppMenu;
 -(void) applyMenu:(AvnMenu* _Nullable)menu;
+-(IAvnAutomationPeer* _Nonnull) automationPeer;
 
 -(double) getExtendedTitleBarHeight;
 -(void) setIsExtended:(bool)value;

native/Avalonia.Native/src/OSX/automation.h

@@ -1,12 +1,13 @@
 #pragma once
 
 #import <Cocoa/Cocoa.h>
+#include "AvnAccessibility.h"
 NS_ASSUME_NONNULL_BEGIN
 
 class IAvnAutomationPeer;
 
-@interface AvnAccessibilityElement : NSAccessibilityElement
-+ (AvnAccessibilityElement *) acquire:(IAvnAutomationPeer *) peer;
+@interface AvnAccessibilityElement : NSAccessibilityElement <AvnAccessibility>
++ (id _Nullable) acquire:(IAvnAutomationPeer *) peer;
 @end
 
 NS_ASSUME_NONNULL_END