Fix callbacks on AOT

Summary:
Based on the idea of #386 by rmarinho
Closes https://github.com/facebook/yoga/pull/388

Reviewed By: emilsjolander

Differential Revision: D4570778

Pulled By: splhack

fbshipit-source-id: 362983deaf6f040c42b3db8205b711e7e5e60eaf

csharp/Facebook.Yoga/Native.cs

@@ -22,6 +22,10 @@ namespace Facebook.Yoga
 
         internal class YGNodeHandle : SafeHandle
         {
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+            private GCHandle _managed;
+#endif
+
             private YGNodeHandle() : base(IntPtr.Zero, true)
             {
             }
@@ -36,10 +40,39 @@ namespace Facebook.Yoga
 
             protected override bool ReleaseHandle()
             {
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+                if (_managed.IsAllocated)
+                {
+                    _managed.Free();
+                }
+#endif
                 Native.YGNodeFree(this.handle);
                 GC.KeepAlive(this);
                 return true;
             }
+
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+            public void SetContext(YogaNode node)
+            {
+                if (!_managed.IsAllocated)
+                {
+                    _managed = GCHandle.Alloc(node, GCHandleType.Weak);
+                    Native.YGNodeSetContext(this.handle, GCHandle.ToIntPtr(_managed));
+                }
+            }
+
+            public static YogaNode GetManaged(IntPtr ygNodePtr)
+            {
+                var node =
+                    GCHandle.FromIntPtr(Native.YGNodeGetContext(ygNodePtr)).Target as YogaNode;
+                if (node == null)
+                {
+                    throw new InvalidOperationException("YogaNode is already deallocated");
+                }
+
+                return node;
+            }
+#endif
         }
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
@@ -68,16 +101,20 @@ namespace Facebook.Yoga
             YogaExperimentalFeature feature);
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
-        public static extern void YGNodeInsertChild(YGNodeHandle node, YGNodeHandle child, uint index);
+        public static extern void YGNodeInsertChild(
+            YGNodeHandle node,
+            YGNodeHandle child,
+            uint index);
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
         public static extern void YGNodeRemoveChild(YGNodeHandle node, YGNodeHandle child);
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
-        public static extern void YGNodeCalculateLayout(YGNodeHandle node,
-                            float availableWidth,
-                            float availableHeight,
-                            YogaDirection parentDirection);
+        public static extern void YGNodeCalculateLayout(
+            YGNodeHandle node,
+            float availableWidth,
+            float availableHeight,
+            YogaDirection parentDirection);
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
         public static extern void YGNodeMarkDirty(YGNodeHandle node);
@@ -105,19 +142,14 @@ namespace Facebook.Yoga
             [MarshalAs(UnmanagedType.FunctionPtr)] YogaBaselineFunc baselineFunc);
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
-        public static extern void YGNodeSetHasNewLayout(YGNodeHandle node, [MarshalAs(UnmanagedType.I1)] bool hasNewLayout);
+        public static extern void YGNodeSetHasNewLayout(
+            YGNodeHandle node,
+            [MarshalAs(UnmanagedType.I1)] bool hasNewLayout);
 
         [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
         [return: MarshalAs(UnmanagedType.I1)]
         public static extern bool YGNodeGetHasNewLayout(YGNodeHandle node);
 
-        [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
-        public static extern void YGNodeSetContext(YGNodeHandle node, IntPtr context);
-
-        [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
-        public static extern IntPtr YGNodeGetContext(IntPtr node);
-
-
         #endregion
 
         #region YG_NODE_STYLE_PROPERTY
@@ -347,5 +379,17 @@ namespace Facebook.Yoga
         public static extern YogaDirection YGNodeLayoutGetDirection(YGNodeHandle node);
 
         #endregion
+
+        #region IOS
+
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+        [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
+        public static extern IntPtr YGNodeGetContext(IntPtr node);
+
+        [DllImport(DllName, ExactSpelling = true, CallingConvention = CallingConvention.Cdecl)]
+        public static extern void YGNodeSetContext(IntPtr node, IntPtr managed);
+#endif
+
+        #endregion
     }
 }

csharp/Facebook.Yoga/YogaLogger.cs

@@ -8,29 +8,26 @@
  */
 
 using System;
+using System.Runtime.InteropServices;
+
+#if __IOS__
+using ObjCRuntime;
+#endif
 
 namespace Facebook.Yoga
 {
     internal static class YogaLogger
     {
+        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
         public delegate void Func(YogaLogLevel level, string message);
 
         private static bool _initialized;
+        private static Func _managedLogger = LoggerInternal;
 
         public static Func Logger = null;
 
-        public static void Initialize()
-        {
-            if (!_initialized)
-            {
-
-                Native.YGInteropSetLogger(LoggerInternal);
-                _initialized = true;
-            }
-        }
-
-#if __IOS__
-        [ObjCRuntime.MonoPInvokeCallback(typeof(Func))]
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+        [MonoPInvokeCallback(typeof(Func))]
 #endif
         public static void LoggerInternal(YogaLogLevel level, string message)
         {
@@ -45,5 +42,13 @@ namespace Facebook.Yoga
             }
         }
 
+        public static void Initialize()
+        {
+            if (!_initialized)
+            {
+                Native.YGInteropSetLogger(_managedLogger);
+                _initialized = true;
+            }
+        }
     }
 }

csharp/Facebook.Yoga/YogaNode.cs

@@ -10,9 +10,15 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-using System.Runtime.InteropServices;
 using System.Text;
 
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+using System.Runtime.InteropServices;
+#endif
+#if __IOS__
+using ObjCRuntime;
+#endif
+
 namespace Facebook.Yoga
 {
     public partial class YogaNode : IEnumerable<YogaNode>
@@ -21,10 +27,15 @@ namespace Facebook.Yoga
         private WeakReference _parent;
         private List<YogaNode> _children;
         private MeasureFunction _measureFunction;
-        private YogaMeasureFunc _ygMeasureFunc;
         private BaselineFunction _baselineFunction;
-        private YogaBaselineFunc _ygBaselineFunc;
         private object _data;
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+        private static YogaMeasureFunc _managedMeasure = MeasureInternalIOS;
+        private static YogaBaselineFunc _managedBaseline = BaselineInternalIOS;
+#else
+        private YogaMeasureFunc _managedMeasure;
+        private YogaBaselineFunc _managedBaseline;
+#endif
 
         public YogaNode()
         {
@@ -545,7 +556,7 @@ namespace Facebook.Yoga
             {
                 while (_children.Count > 0)
                 {
-                    RemoveAt(_children.Count - 1);
+                    RemoveAt(_children.Count-1);
                 }
             }
         }
@@ -558,23 +569,29 @@ namespace Facebook.Yoga
         public void SetMeasureFunction(MeasureFunction measureFunction)
         {
             _measureFunction = measureFunction;
-            _ygMeasureFunc = measureFunction != null ? MeasureInternal : (YogaMeasureFunc)null;
-
-            var handle = GCHandle.Alloc(this);
-            Native.YGNodeSetContext(_ygNode, GCHandle.ToIntPtr(handle));
-
-            Native.YGNodeSetMeasureFunc(_ygNode, _ygMeasureFunc);
+            if (measureFunction != null)
+            {
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+                _ygNode.SetContext(this);
+#else
+                _managedMeasure = MeasureInternal;
+#endif
+            }
+            Native.YGNodeSetMeasureFunc(_ygNode, _managedMeasure);
         }
 
         public void SetBaselineFunction(BaselineFunction baselineFunction)
         {
             _baselineFunction = baselineFunction;
-            _ygBaselineFunc = baselineFunction != null ? BaselineInternal : (YogaBaselineFunc)null;
-
-            var handle = GCHandle.Alloc(this);
-            Native.YGNodeSetContext(_ygNode, GCHandle.ToIntPtr(handle));
-
-            Native.YGNodeSetBaselineFunc(_ygNode, _ygBaselineFunc);
+            if (baselineFunction != null)
+            {
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+                _ygNode.SetContext(this);
+#else
+                _managedBaseline = BaselineInternal;
+#endif
+            }
+            Native.YGNodeSetBaselineFunc(_ygNode, _managedBaseline);
         }
 
         public void CalculateLayout()
@@ -586,55 +603,63 @@ namespace Facebook.Yoga
                 Native.YGNodeStyleGetDirection(_ygNode));
         }
 
-#if __IOS__
-        [ObjCRuntime.MonoPInvokeCallback(typeof(YogaMeasureFunc))]
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+        [MonoPInvokeCallback(typeof(YogaMeasureFunc))]
+        private static YogaSize MeasureInternalIOS(
+            IntPtr ygNodePtr,
+            float width,
+            YogaMeasureMode widthMode,
+            float height,
+            YogaMeasureMode heightMode)
+        {
+            var node = Native.YGNodeHandle.GetManaged(ygNodePtr);
+            return node.MeasureInternal(IntPtr.Zero, width, widthMode, height, heightMode);
+        }
 #endif
-        private static YogaSize MeasureInternal(
+
+        private YogaSize MeasureInternal(
             IntPtr node,
             float width,
             YogaMeasureMode widthMode,
             float height,
             YogaMeasureMode heightMode)
         {
-
-            var yogaNodePointer = Native.YGNodeGetContext(node);
-
-            YogaNode yogaNode = GCHandle.FromIntPtr(yogaNodePointer).Target as YogaNode;
-
-            var measureFunction = yogaNode._measureFunction;
-            if (measureFunction == null)
+            if (_measureFunction == null)
             {
                 throw new InvalidOperationException("Measure function is not defined.");
             }
 
-            return measureFunction(yogaNode, width, widthMode, height, heightMode);
+            return _measureFunction(this, width, widthMode, height, heightMode);
         }
 
-
-#if __IOS__
-        [ObjCRuntime.MonoPInvokeCallback(typeof(YogaBaselineFunc))]
-#endif
-        private static float BaselineInternal(IntPtr node, float width, float height)
+#if (UNITY_IOS && !UNITY_EDITOR) || __IOS__
+        [MonoPInvokeCallback(typeof(YogaBaselineFunc))]
+        private static float BaselineInternalIOS(
+            IntPtr ygNodePtr,
+            float width,
+            float height)
         {
-            var yogaNodePointer = Native.YGNodeGetContext(node);
+            var node = Native.YGNodeHandle.GetManaged(ygNodePtr);
+            return node.BaselineInternal(IntPtr.Zero, width, height);
+        }
+#endif
 
-            YogaNode yogaNode = GCHandle.FromIntPtr(yogaNodePointer).Target as YogaNode;
-
-            var baselineFunction = yogaNode._baselineFunction;
-            if (baselineFunction == null)
+        private float BaselineInternal(IntPtr node, float width, float height)
+        {
+            if (_baselineFunction == null)
             {
                 throw new InvalidOperationException("Baseline function is not defined.");
             }
 
-            return baselineFunction(yogaNode, width, height);
+            return _baselineFunction(this, width, height);
         }
 
         public string Print(YogaPrintOptions options =
-            YogaPrintOptions.Layout | YogaPrintOptions.Style | YogaPrintOptions.Children)
+            YogaPrintOptions.Layout|YogaPrintOptions.Style|YogaPrintOptions.Children)
         {
             StringBuilder sb = new StringBuilder();
             YogaLogger.Func orig = YogaLogger.Logger;
-            YogaLogger.Logger = (level, message) => { sb.Append(message); };
+            YogaLogger.Logger = (level, message) => {sb.Append(message);};
             Native.YGNodePrint(_ygNode, options);
             YogaLogger.Logger = orig;
             return sb.ToString();