Add CallbackBase impl

src/Avalonia.MicroCom/CallbackBase.cs

@@ -0,0 +1,53 @@
+namespace Avalonia.MicroCom
+{
+    public abstract class CallbackBase : IUnknown, IMicroComShadowContainer
+    {
+        private readonly object _lock = new object();
+        private bool _referencedFromManaged = true;
+        private bool _referencedFromNative = false;
+        private bool _destroyed;
+
+        public bool IsDestroyed => _destroyed;
+
+        protected virtual void Destroyed()
+        {
+
+        }
+
+        public void Dispose()
+        {
+            lock (_lock)
+            {
+                _referencedFromManaged = false;
+                DestroyIfNeeded();
+            }
+        }
+
+        void DestroyIfNeeded()
+        {
+            if(_destroyed)
+                return;
+            if (_referencedFromManaged == false && _referencedFromNative == false)
+            {
+                _destroyed = true;
+                Destroyed();
+            }
+        }
+
+        public MicroComShadow Shadow { get; set; }
+        public void OnReferencedFromNative()
+        {
+            lock (_lock) 
+                _referencedFromNative = true;
+        }
+
+        public void OnUnreferencedFromNative()
+        {
+            lock (_lock)
+            {
+                _referencedFromNative = false;
+                DestroyIfNeeded();
+            }
+        }
+    }
+}

src/Avalonia.Native/AvaloniaNativeApplicationPlatform.cs

@@ -6,7 +6,7 @@ using Avalonia.Platform;
 
 namespace Avalonia.Native
 {
-    internal class AvaloniaNativeApplicationPlatform : CallbackBase, IAvnApplicationEvents, IPlatformLifetimeEventsImpl
+    internal class AvaloniaNativeApplicationPlatform : NativeCallbackBase, IAvnApplicationEvents, IPlatformLifetimeEventsImpl
     {
         public event EventHandler<ShutdownRequestedEventArgs> ShutdownRequested;
         

src/Avalonia.Native/AvaloniaNativeDragSource.cs

@@ -30,7 +30,7 @@ namespace Avalonia.Native
             return visual.VisualRoot as TopLevel;
         }
 
-        class DndCallback : CallbackBase, IAvnDndResultCallback
+        class DndCallback : NativeCallbackBase, IAvnDndResultCallback
         {
             private TaskCompletionSource<DragDropEffects> _tcs;
 

src/Avalonia.Native/AvaloniaNativePlatform.cs

@@ -79,7 +79,7 @@ namespace Avalonia.Native
             _factory = factory;
         }
 
-        class GCHandleDeallocator : CallbackBase, IAvnGCHandleDeallocatorCallback
+        class GCHandleDeallocator : NativeCallbackBase, IAvnGCHandleDeallocatorCallback
         {
             public void FreeGCHandle(IntPtr handle)
             {

src/Avalonia.Native/CallbackBase.cs

@@ -5,19 +5,8 @@ using Avalonia.Platform;
 
 namespace Avalonia.Native
 {
-    public class CallbackBase : IUnknown, IMicroComShadowContainer, IMicroComExceptionCallback
+    public abstract class NativeCallbackBase : CallbackBase, IMicroComExceptionCallback
     {
-        private readonly object _lock = new object();
-        private bool _referencedFromManaged = true;
-        private bool _referencedFromNative = false;
-        private bool _destroyed;
-        
-
-        protected virtual void Destroyed()
-        {
-
-        }
-
         public void RaiseException(Exception e)
         {
             if (AvaloniaLocator.Current.GetService<IPlatformThreadingInterface>() is PlatformThreadingInterface threadingInterface)
@@ -27,41 +16,5 @@ namespace Avalonia.Native
                 threadingInterface.DispatchException(ExceptionDispatchInfo.Capture(e));
             }
         }
-
-        public void Dispose()
-        {
-            lock (_lock)
-            {
-                _referencedFromManaged = false;
-                DestroyIfNeeded();
-            }
-        }
-
-        void DestroyIfNeeded()
-        {
-            if(_destroyed)
-                return;
-            if (_referencedFromManaged == false && _referencedFromNative == false)
-            {
-                _destroyed = true;
-                Destroyed();
-            }
-        }
-
-        public MicroComShadow Shadow { get; set; }
-        public void OnReferencedFromNative()
-        {
-            lock (_lock) 
-                _referencedFromNative = true;
-        }
-
-        public void OnUnreferencedFromNative()
-        {
-            lock (_lock)
-            {
-                _referencedFromNative = false;
-                DestroyIfNeeded();
-            }
-        }
     }
 }

src/Avalonia.Native/DeferredFramebuffer.cs

@@ -27,7 +27,7 @@ namespace Avalonia.Native
         public Vector Dpi { get; set; }
         public PixelFormat Format { get; set; }
 
-        class Disposer : CallbackBase
+        class Disposer : NativeCallbackBase
         {
             private IntPtr _ptr;
 

src/Avalonia.Native/IAvnMenu.cs

@@ -7,7 +7,7 @@ using Avalonia.Platform.Interop;
 
 namespace Avalonia.Native.Interop
 {
-    class MenuEvents : CallbackBase, IAvnMenuEvents
+    class MenuEvents : NativeCallbackBase, IAvnMenuEvents
     {
         private IAvnMenu _parent;
 

src/Avalonia.Native/MenuActionCallback.cs

@@ -3,7 +3,7 @@ using Avalonia.Native.Interop;
 
 namespace Avalonia.Native
 {
-    public class MenuActionCallback : CallbackBase, IAvnActionCallback
+    public class MenuActionCallback : NativeCallbackBase, IAvnActionCallback
     {
         private Action _action;
 

src/Avalonia.Native/PlatformThreadingInterface.cs

@@ -9,7 +9,7 @@ namespace Avalonia.Native
 {
     internal class PlatformThreadingInterface : IPlatformThreadingInterface
     {
-        class TimerCallback : CallbackBase, IAvnActionCallback
+        class TimerCallback : NativeCallbackBase, IAvnActionCallback
         {
             readonly Action _tick;
 
@@ -24,7 +24,7 @@ namespace Avalonia.Native
             }
         }
 
-        class SignaledCallback : CallbackBase, IAvnSignaledCallback
+        class SignaledCallback : NativeCallbackBase, IAvnSignaledCallback
         {
             readonly PlatformThreadingInterface _parent;
 

src/Avalonia.Native/PredicateCallback.cs

@@ -3,7 +3,7 @@ using Avalonia.Native.Interop;
 
 namespace Avalonia.Native
 {
-    public class PredicateCallback : CallbackBase, IAvnPredicateCallback
+    public class PredicateCallback : NativeCallbackBase, IAvnPredicateCallback
     {
         private Func<bool> _predicate;
 

src/Avalonia.Native/SystemDialogs.cs

@@ -62,7 +62,7 @@ namespace Avalonia.Native
         }
     }
 
-    internal unsafe class SystemDialogEvents : CallbackBase, IAvnSystemDialogEvents
+    internal unsafe class SystemDialogEvents : NativeCallbackBase, IAvnSystemDialogEvents
     {
         private TaskCompletionSource<string[]> _tcs;
 

src/Avalonia.Native/WindowImplBase.cs

@@ -151,7 +151,7 @@ namespace Avalonia.Native
         public IMouseDevice MouseDevice => _mouse;
         public abstract IPopupImpl CreatePopup();
 
-        protected unsafe class WindowBaseEvents : CallbackBase, IAvnWindowBaseEvents
+        protected unsafe class WindowBaseEvents : NativeCallbackBase, IAvnWindowBaseEvents
         {
             private readonly WindowBaseImpl _parent;
 

src/Windows/Avalonia.Win32/DataObject.cs

@@ -49,18 +49,16 @@ namespace Avalonia.Win32
         }
     }
 
-    internal class DataObject : IDisposableDataObject, Win32Com.IAvnDataObject, IMicroComShadowContainer
+    internal class DataObject : CallbackBase, IDisposableDataObject, Win32Com.IAvnDataObject
     {
         // Compatibility with WinForms + WPF...
         internal static readonly byte[] SerializedObjectGUID = new Guid("FD9EA796-3B13-4370-A679-56106BB288FB").ToByteArray();
 
-        class FormatEnumerator : Win32Com.IEnumFORMATETC, IMicroComShadowContainer
+        class FormatEnumerator : CallbackBase, Win32Com.IEnumFORMATETC
         {
             private FORMATETC[] _formats;
             private uint _current;
 
-            public MicroComShadow Shadow { get; set; }
-
             private FormatEnumerator(FORMATETC[] formats, uint current)
             {
                 _formats = formats;
@@ -76,7 +74,7 @@ namespace Avalonia.Win32
             private FORMATETC ConvertToFormatEtc(string aFormatName)
             {
                 FORMATETC result = default(FORMATETC);
-                result.cfFormat = (ushort)ClipboardFormats.GetFormat(aFormatName);
+                result.cfFormat = ClipboardFormats.GetFormat(aFormatName);
                 result.dwAspect = DVASPECT.DVASPECT_CONTENT;
                 result.ptd = IntPtr.Zero;
                 result.lindex = -1;
@@ -123,18 +121,6 @@ namespace Avalonia.Win32
             {
                 return new FormatEnumerator(_formats, _current);
             }
-
-            public void Dispose()
-            {
-            }
-
-            public void OnReferencedFromNative()
-            {
-            }
-
-            public void OnUnreferencedFromNative()
-            {
-            }
         }
 
         private const uint DV_E_TYMED = 0x80040069;
@@ -149,8 +135,6 @@ namespace Avalonia.Win32
 
         IDataObject _wrapped;
 
-        public MicroComShadow Shadow { get; set; }
-
         public DataObject(IDataObject wrapped)
         {
             if (_wrapped is DataObject || _wrapped is OleDataObject)
@@ -426,18 +410,10 @@ namespace Avalonia.Win32
             }
         }
 
-        public void Dispose()
+        protected override void Destroyed()
-        {
-        }
-
-        public void OnReferencedFromNative()
         {
+            base.Destroyed();
         }
-
-        public void OnUnreferencedFromNative()
-        {
-        }
-
         #endregion
     }
 }

src/Windows/Avalonia.Win32/OleDragSource.cs

@@ -6,7 +6,7 @@ using Avalonia.Win32.Win32Com;
 
 namespace Avalonia.Win32
 {
-    internal class OleDragSource : IDropSource, IMicroComShadowContainer
+    internal class OleDragSource : CallbackBase, IDropSource
     {
         private const int DRAGDROP_S_USEDEFAULTCURSORS = 0x00040102;
         private const int DRAGDROP_S_DROP = 0x00040100;
@@ -18,8 +18,6 @@ namespace Avalonia.Win32
             (int)UnmanagedMethods.ModifierKeys.MK_RBUTTON
         };
 
-        public MicroComShadow Shadow { get; set; }
-
         public int QueryContinueDrag(int fEscapePressed, int grfKeyState)
         {
             if (fEscapePressed != 0)
@@ -39,17 +37,5 @@ namespace Avalonia.Win32
         {
             return DRAGDROP_S_USEDEFAULTCURSORS;
         }
-
-        public void Dispose()
-        {
-        }
-
-        public void OnReferencedFromNative()
-        {
-        }
-
-        public void OnUnreferencedFromNative()
-        {
-        }
     }
 }

src/Windows/Avalonia.Win32/OleDropTarget.cs

@@ -7,7 +7,7 @@ using DropEffect = Avalonia.Win32.Win32Com.DropEffect;
 
 namespace Avalonia.Win32
 {
-    internal class OleDropTarget : Win32Com.IDropTarget, IMicroComShadowContainer
+    internal class OleDropTarget : CallbackBase, Win32Com.IDropTarget
     {
         private readonly IInputRoot _target;
         private readonly ITopLevelImpl _tl;
@@ -15,8 +15,6 @@ namespace Avalonia.Win32
         
         private IDisposableDataObject _currentDrag = null;
 
-        public MicroComShadow Shadow { get; set; }
-
         public OleDropTarget(ITopLevelImpl tl, IInputRoot target)
         {
             _dragDevice = AvaloniaLocator.Current.GetService<IDragDropDevice>();
@@ -180,17 +178,9 @@ namespace Avalonia.Win32
             return _target.PointToClient(screenPt);
         }
 
-        public void Dispose()
+        protected override void Destroyed()
         {
             _currentDrag?.Dispose();
         }
-
-        public void OnReferencedFromNative()
-        {
-        }
-
-        public void OnUnreferencedFromNative()
-        {
-        }
     }
 }