[NUI] Make InputMethodContext's signal callbacks not collected

This PR makes InputMethodContext's signal callbacks not collected before
native InputMethodContext gone.

Unlike other classes, InputMethodContext's callbacks are not removed
from the static dictionary until it is disposed.
Because eventReceivedEventCallback is called from unmanaged code
although it is disconnected.

diff --git a/src/Tizen.NUI/src/public/Input/InputMethodContext.cs b/src/Tizen.NUI/src/public/Input/InputMethodContext.cs
index e747f301c8d37b7c3643fced1f15dbb57f01abaa..5a4e64441d637a7047c4f913b0b167924245106d 100755 (executable)
--- a/src/Tizen.NUI/src/public/Input/InputMethodContext.cs
+++ b/src/Tizen.NUI/src/public/Input/InputMethodContext.cs
@@ -77,7 +77,7 @@ namespace Tizen.NUI
             {
                 if (activatedEventHandler == null)
                 {
-                    activatedEventCallback = OnActivated;
+                    CreateSafeCallback(OnActivated, out activatedEventCallback);
                     ActivatedSignal().Connect(activatedEventCallback);
                 }
 
@@ -90,6 +90,7 @@ namespace Tizen.NUI
                 if (activatedEventHandler == null && activatedEventCallback != null)
                 {
                     ActivatedSignal().Disconnect(activatedEventCallback);
+                    ReleaseSafeCallback(ref activatedEventCallback);
                 }
             }
         }
@@ -104,7 +105,7 @@ namespace Tizen.NUI
             {
                 if (eventReceivedEventHandler == null)
                 {
-                    eventReceivedEventCallback = OnEventReceived;
+                    CreateSafeCallback(OnEventReceived, out eventReceivedEventCallback);
                     EventReceivedSignal().Connect(eventReceivedEventCallback);
                 }
 
@@ -117,6 +118,7 @@ namespace Tizen.NUI
                 if (eventReceivedEventHandler == null && eventReceivedEventCallback != null)
                 {
                     EventReceivedSignal().Disconnect(eventReceivedEventCallback);
+                    ReleaseSafeCallback(ref eventReceivedEventCallback);
                 }
             }
         }
@@ -131,7 +133,7 @@ namespace Tizen.NUI
             {
                 if (statusChangedEventHandler == null)
                 {
-                    statusChangedEventCallback = OnStatusChanged;
+                    CreateSafeCallback(OnStatusChanged, out statusChangedEventCallback);
                     StatusChangedSignal().Connect(statusChangedEventCallback);
                 }
 
@@ -144,6 +146,7 @@ namespace Tizen.NUI
                 if (statusChangedEventHandler == null && statusChangedEventCallback != null)
                 {
                     StatusChangedSignal().Disconnect(statusChangedEventCallback);
+                    ReleaseSafeCallback(ref statusChangedEventCallback);
                 }
             }
         }
@@ -158,7 +161,7 @@ namespace Tizen.NUI
             {
                 if (resizedEventHandler == null)
                 {
-                    resizedEventCallback = OnResized;
+                    CreateSafeCallback(OnResized, out resizedEventCallback);
                     ResizedSignal().Connect(resizedEventCallback);
                 }
 
@@ -171,6 +174,7 @@ namespace Tizen.NUI
                 if (resizedEventHandler == null && resizedEventCallback != null)
                 {
                     ResizedSignal().Disconnect(resizedEventCallback);
+                    ReleaseSafeCallback(ref resizedEventCallback);
                 }
             }
         }
@@ -185,7 +189,7 @@ namespace Tizen.NUI
             {
                 if (languageChangedEventHandler == null)
                 {
-                    languageChangedEventCallback = OnLanguageChanged;
+                    CreateSafeCallback(OnLanguageChanged, out languageChangedEventCallback);
                     LanguageChangedSignal().Connect(languageChangedEventCallback);
                 }
 
@@ -198,6 +202,7 @@ namespace Tizen.NUI
                 if (languageChangedEventHandler == null && languageChangedEventCallback != null)
                 {
                     LanguageChangedSignal().Disconnect(languageChangedEventCallback);
+                    ReleaseSafeCallback(ref languageChangedEventCallback);
                 }
             }
         }
@@ -212,7 +217,7 @@ namespace Tizen.NUI
             {
                 if (keyboardTypeChangedEventHandler == null)
                 {
-                    keyboardTypeChangedEventCallback = OnKeyboardTypeChanged;
+                    CreateSafeCallback(OnKeyboardTypeChanged, out keyboardTypeChangedEventCallback);
                     KeyboardTypeChangedSignal().Connect(keyboardTypeChangedEventCallback);
                 }
 
@@ -225,6 +230,7 @@ namespace Tizen.NUI
                 if (keyboardTypeChangedEventHandler == null && keyboardTypeChangedEventCallback != null)
                 {
                     KeyboardTypeChangedSignal().Disconnect(keyboardTypeChangedEventCallback);
+                    ReleaseSafeCallback(ref keyboardTypeChangedEventCallback);
                 }
             }
         }
@@ -240,7 +246,7 @@ namespace Tizen.NUI
             {
                 if (contentReceivedEventHandler == null)
                 {
-                    contentReceivedEventCallback = OnContentReceived;
+                    CreateSafeCallback(OnContentReceived, out contentReceivedEventCallback);
                     ContentReceivedSignal().Connect(contentReceivedEventCallback);
                 }
 
@@ -253,6 +259,7 @@ namespace Tizen.NUI
                 if (contentReceivedEventHandler == null && contentReceivedEventCallback != null)
                 {
                     ContentReceivedSignal().Disconnect(contentReceivedEventCallback);
+                    ReleaseSafeCallback(ref contentReceivedEventCallback);
                 }
             }
         }
@@ -879,42 +886,63 @@ namespace Tizen.NUI
             //You should not access any managed member here except static instance
             //because the execution order of Finalizes is non-deterministic.
 
+            if (type == DisposeTypes.Explicit)
+            {
+                DisconnectNativeSignals();
+            }
+
+            base.Dispose(type);
+        }
+
+        private void DisconnectNativeSignals()
+        {
+            if (HasBody() == false)
+            {
+                NUILog.Debug($"[Dispose] DisConnectFromSignals() No native body! No need to Disconnect Signals!");
+                return;
+            }
+
             if (activatedEventCallback != null)
             {
                 ActivatedSignal().Disconnect(activatedEventCallback);
+                activatedEventCallback = null;
             }
 
             if (eventReceivedEventCallback != null)
             {
                 EventReceivedSignal().Disconnect(eventReceivedEventCallback);
+                eventReceivedEventCallback = null;
             }
 
             if (statusChangedEventCallback != null)
             {
                 StatusChangedSignal().Disconnect(statusChangedEventCallback);
+                statusChangedEventCallback = null;
             }
 
             if (resizedEventCallback != null)
             {
                 ResizedSignal().Disconnect(resizedEventCallback);
+                resizedEventCallback = null;
             }
 
             if (languageChangedEventCallback != null)
             {
                 LanguageChangedSignal().Disconnect(languageChangedEventCallback);
+                languageChangedEventCallback = null;
             }
 
             if (keyboardTypeChangedEventCallback != null)
             {
                 KeyboardTypeChangedSignal().Disconnect(keyboardTypeChangedEventCallback);
+                keyboardTypeChangedEventCallback = null;
             }
 
             if (contentReceivedEventCallback != null)
             {
                 ContentReceivedSignal().Disconnect(contentReceivedEventCallback);
+                contentReceivedEventCallback = null;
             }
-
-            base.Dispose(type);
         }
 
         /// This will not be public opened.
@@ -1069,6 +1097,22 @@ namespace Tizen.NUI
             }
         }
 
+        void CreateSafeCallback<T>(T method, out T safeCallback) where T : Delegate
+        {
+            AddToNativeHolder(method);
+            safeCallback = method;
+        }
+
+        void ReleaseSafeCallback<T>(ref T safeCallback) where T : Delegate
+        {
+            System.Diagnostics.Debug.Assert(safeCallback != null);
+            // FIXME: If eventReceivedEventCallback is removed from nativeholder,
+            //        then it is called from unmanaged code although it is disconnected.
+            //        So the callbacks are not removed from nativeholder until dispose.
+            // RemoveFromNativeHolder(safeCallback);
+            safeCallback = null;
+        }
+
         /// <summary>
         /// This structure is used to pass on data from the IMF regarding predictive text.
         /// </summary>