[csharp] Add YogaKit shared implementation

csharp/Facebook.YogaKit/Facebook.YogaKit.Shared.shproj

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <ProjectGuid>{A24B3BA6-3143-4FFF-B8B8-1EDF166F5F4A}</ProjectGuid>
+  </PropertyGroup>
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.Default.props" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.props" />
+  <Import Project="Facebook.YogaKit.projitems" Label="Shared" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.CSharp.targets" />
+</Project>

csharp/Facebook.YogaKit/Facebook.YogaKit.projitems

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
+    <HasSharedItems>true</HasSharedItems>
+    <SharedGUID>{A24B3BA6-3143-4FFF-B8B8-1EDF166F5F4A}</SharedGUID>
+  </PropertyGroup>
+  <PropertyGroup Label="Configuration">
+    <Import_RootNamespace>Facebook.YogaKit</Import_RootNamespace>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)YogaKit.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)YogaKitNative.cs" />
+  </ItemGroup>
+</Project>

csharp/Facebook.YogaKit/YogaKit.cs

@@ -0,0 +1,180 @@
+using System;
+using System.Collections.Generic;
+using Facebook.Yoga;
+#if __IOS__
+using NativeView = UIKit.UIView;
+#endif
+
+namespace Facebook.YogaKit
+{
+	public static class YogaKit
+	{
+		internal static Dictionary<YogaNode, object> Bridges = new Dictionary<YogaNode, object>();
+
+		public static void UsesYoga(this NativeView view, bool usesYoga)
+		{
+			YogaKitNative.UsesYoga(view, usesYoga);
+		}
+
+		public static bool GetUsesYoga(this NativeView view)
+		{
+			return YogaKitNative.GetUsesYoga(view);
+		}
+
+		public static void IncludeYogaLayout(this NativeView view, bool includeInLayout)
+		{
+			YogaKitNative.IncludeYogaLayout(view, includeInLayout);
+		}
+
+		public static bool GetIncludeYogaLayout(this NativeView view)
+		{
+			return YogaKitNative.GetIncludeYogaLayout(view);
+		}
+
+		public static void YogaWidth(this NativeView view, nfloat width)
+		{
+			var node = GetYogaNode(view);
+			node.Width = (float)width;
+		}
+
+		public static void YogaHeight(this NativeView view, nfloat height)
+		{
+			var node = GetYogaNode(view);
+			node.Height = (float)height;
+		}
+
+		public static void YogaMinWidth(this NativeView view, float minWidth)
+		{
+			var node = GetYogaNode(view);
+			node.MinWidth = minWidth;
+		}
+
+		public static void YogaMinHeight(this NativeView view, float minHeight)
+		{
+			var node = GetYogaNode(view);
+			node.MinHeight = minHeight;
+		}
+
+		public static void YogaMaxWidth(this NativeView view, float maxWidth)
+		{
+			var node = GetYogaNode(view);
+			node.MaxWidth = maxWidth;
+		}
+
+		public static void YogaMaxHeight(this NativeView view, float maxHeight)
+		{
+			var node = GetYogaNode(view);
+			node.MaxHeight = maxHeight;
+		}
+
+		public static void YogaAlignItems(this NativeView view, YogaAlign align)
+		{
+			var node = GetYogaNode(view);
+			node.AlignItems = align;
+		}
+
+		public static void YogaJustify(this NativeView view, YogaJustify justify)
+		{
+			var node = GetYogaNode(view);
+			node.JustifyContent = justify;
+		}
+
+		public static void YogaAlign(this NativeView view, YogaAlign align)
+		{
+			var node = GetYogaNode(view);
+			node.AlignContent = align;
+		}
+
+		public static void YogaAlignSelf(this NativeView view, YogaAlign align)
+		{
+			var node = GetYogaNode(view);
+			node.AlignSelf = align;
+		}
+
+		public static void YogaDirection(this NativeView view, YogaDirection direction)
+		{
+			var node = GetYogaNode(view);
+			node.StyleDirection = direction;
+		}
+
+		public static void YogaFlexDirection(this NativeView view, YogaFlexDirection direction)
+		{
+			var node = GetYogaNode(view);
+			node.FlexDirection = direction;
+		}
+
+		public static void YogaPositionType(this NativeView view, YogaPositionType position)
+		{
+			var node = GetYogaNode(view);
+			node.PositionType = position;
+		}
+
+		public static void YogaFlexWrap(this NativeView view, YogaWrap wrap)
+		{
+			var node = GetYogaNode(view);
+			node.Wrap = wrap;
+		}
+
+		public static void YogaFlexShrink(this NativeView view, float shrink)
+		{
+			var node = GetYogaNode(view);
+			node.FlexShrink = shrink;
+		}
+
+		public static void YogaFlexGrow(this NativeView view, float grow)
+		{
+			var node = GetYogaNode(view);
+			node.FlexGrow = grow;
+		}
+
+		public static void YogaFlexBasis(this NativeView view, float basis)
+		{
+			var node = GetYogaNode(view);
+			node.FlexBasis = basis;
+		}
+
+		public static void YogaPositionForEdge(this NativeView view, float position, YogaEdge edge)
+		{
+			var node = GetYogaNode(view);
+			node.SetPosition(edge, position);
+		}
+
+		public static void YogaMarginForEdge(this NativeView view, float margin, YogaEdge edge)
+		{
+			var node = GetYogaNode(view);
+			node.SetMargin(edge, margin);
+		}
+
+		public static void YogaPaddingForEdge(this NativeView view, float padding, YogaEdge edge)
+		{
+			var node = GetYogaNode(view);
+			node.SetPadding(edge, padding);
+		}
+
+		public static void YogaAspectRation(this NativeView view, float ratio)
+		{
+			var node = GetYogaNode(view);
+			node.StyleAspectRatio = ratio;
+		}
+
+		#region Layout and Sizing
+		public static void YogaApplyLayout(this NativeView view)
+		{
+			YogaKitNative.CalculateLayoutWithSize(view, view.Bounds.Size);
+			YogaKitNative.ApplyLayoutToViewHierarchy(view);
+		}
+
+		public static YogaDirection YogaResolvedDirection(this NativeView view)
+		{
+			var node = GetYogaNode(view);
+			return node.LayoutDirection;
+		}
+
+		#endregion
+
+		public static YogaNode GetYogaNode(this NativeView view)
+		{
+			return YogaKitNative.GetYogaNode(view);
+		}
+	}
+}

csharp/Facebook.YogaKit/YogaKitNative.cs

@@ -0,0 +1,255 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using Facebook.Yoga;
+#if __IOS__
+using CoreGraphics;
+using Foundation;
+using UIKit;
+#endif
+
+namespace Facebook.YogaKit
+{
+	internal static class YogaKitNative
+	{
+		static NSString YogaNodeKey = new NSString("YogaNode");
+
+		static NSString UsesYogaKey = new NSString("UsesYoga");
+
+		static NSString IncludeYogaKey = new NSString("UsesYoga");
+
+		public static void UsesYoga(UIView view, bool usesYoga)
+		{
+			var value = NSNumber.FromBoolean(usesYoga);
+			objc_setAssociatedObject(view.Handle, UsesYogaKey.Handle, value.Handle, AssociationPolicy.RETAIN_NONATOMIC);
+		}
+
+		public static bool GetUsesYoga(UIView view)
+		{
+			var value = ObjCRuntime.Runtime.GetNSObject(objc_getAssociatedObject(view.Handle, UsesYogaKey.Handle)) as NSNumber;
+			return value == null ? false : value.BoolValue;
+		}
+
+		public static void IncludeYogaLayout(UIView view, bool includeInLayout)
+		{
+			var value = NSNumber.FromBoolean(includeInLayout);
+			objc_setAssociatedObject(view.Handle, IncludeYogaKey.Handle, value.Handle, AssociationPolicy.RETAIN_NONATOMIC);
+		}
+
+		public static bool GetIncludeYogaLayout(UIView view)
+		{
+			var value = ObjCRuntime.Runtime.GetNSObject(objc_getAssociatedObject(view.Handle, IncludeYogaKey.Handle)) as NSNumber;
+			return value == null ? true : value.BoolValue;
+		}
+
+		public static YogaNode GetYogaNode(UIView view)
+		{
+			var value = ObjCRuntime.Runtime.GetNSObject(objc_getAssociatedObject(view.Handle, YogaNodeKey.Handle)) as YGNodeBridge;
+			if (value == null)
+			{
+				value = new YGNodeBridge();
+				value.SetContext(view);
+				objc_setAssociatedObject(view.Handle, YogaNodeKey.Handle, value.Handle, AssociationPolicy.RETAIN_NONATOMIC);
+			}
+			return value.node;
+		}
+
+		public static CGSize CalculateLayoutWithSize(UIView view, CGSize size)
+		{
+			if (!view.GetUsesYoga())
+			{
+				System.Diagnostics.Debug.WriteLine("Doesn't use Yoga");
+			}
+			AttachNodesFromViewHierachy(view);
+			var node = GetYogaNode(view);
+
+			node.Width = (float)size.Width;
+			node.Height = (float)size.Height;
+			node.CalculateLayout();
+
+			return new CGSize { Width = node.LayoutWidth, Height = node.LayoutHeight };
+		}
+
+		public static void ApplyLayoutToViewHierarchy(UIView view)
+		{
+			if (!view.GetIncludeYogaLayout())
+				return;
+
+			var node = GetYogaNode(view);
+			CGPoint topLeft = new CGPoint(node.LayoutX, node.LayoutY);
+			CGPoint bottomRight = new CGPoint(topLeft.X + node.LayoutWidth, topLeft.Y + node.LayoutHeight);
+			view.Frame = new CGRect(RoundPixelValue(topLeft.X), RoundPixelValue(topLeft.Y), RoundPixelValue(bottomRight.X) - RoundPixelValue(topLeft.X), RoundPixelValue(bottomRight.Y) - RoundPixelValue(topLeft.Y));
+			bool isLeaf = !view.GetUsesYoga() || view.Subviews.Length == 0;
+			if (!isLeaf)
+			{
+				for (int i = 0; i < view.Subviews.Length; i++)
+				{
+					ApplyLayoutToViewHierarchy(view.Subviews[i]);
+				}
+			}
+		}
+
+		public static CGSize YogaIntrinsicSize(this UIView view)
+		{
+			var constrainedSize = new CGSize
+			{
+				Width = float.NaN,
+				Height = float.NaN
+			};
+			return CalculateLayoutWithSize(view, constrainedSize);
+		}
+
+		static YogaSize MeasureView(YogaNode node, float width, YogaMeasureMode widthMode, float height, YogaMeasureMode heightMode)
+		{
+			var constrainedWidth = (widthMode == YogaMeasureMode.Undefined) ? nfloat.MaxValue : width;
+			var constrainedHeight = (heightMode == YogaMeasureMode.Undefined) ? nfloat.MaxValue : height;
+
+			UIView view = null;
+			if (YogaKit.Bridges.ContainsKey(node))
+				(YogaKit.Bridges[node] as YGNodeBridge).viewRef.TryGetTarget(out view);
+
+			var sizeThatFits = view.SizeThatFits(new CGSize(constrainedWidth, constrainedHeight));
+
+			var finalWidth = SanitizeMeasurement(constrainedWidth, sizeThatFits.Width, widthMode);
+			var finalHeight = SanitizeMeasurement(constrainedHeight, sizeThatFits.Height, heightMode);
+
+			return MeasureOutput.Make(finalWidth, finalHeight);
+		}
+
+		static float SanitizeMeasurement(nfloat constrainedSize, nfloat measuredSize, YogaMeasureMode measureMode)
+		{
+			float result;
+			if (measureMode == YogaMeasureMode.Exactly)
+			{
+				result = (float)constrainedSize;
+			}
+			else if (measureMode == YogaMeasureMode.AtMost)
+			{
+				result = (float)Math.Min(constrainedSize, measuredSize);
+			}
+			else {
+				result = (float)measuredSize;
+			}
+
+			return result;
+
+		}
+
+		static double RoundPixelValue(nfloat value)
+		{
+			nfloat scale = UIScreen.MainScreen.Scale;
+
+			return Math.Round(value * scale) / scale;
+		}
+
+		static void AttachNodesFromViewHierachy(UIView view)
+		{
+			var node = GetYogaNode(view);
+
+			// Only leaf nodes should have a measure function
+			if (!view.GetUsesYoga() || view.Subviews.Length == 0)
+			{
+				node.SetMeasureFunction(MeasureView);
+				RemoveAllChildren(node);
+			}
+			else
+			{
+				node.SetMeasureFunction(null);
+				// Create a list of all the subviews that we are going to use for layout.
+				var subviewsToInclude = new List<UIView>();
+				foreach (var subview in view.Subviews)
+				{
+					if (subview.GetIncludeYogaLayout())
+					{
+						subviewsToInclude.Add(subview);
+					}
+				}
+
+				var shouldReconstructChildList = false;
+				if (node.Count != subviewsToInclude.Count)
+				{
+					shouldReconstructChildList = true;
+				}
+				else
+				{
+					for (int i = 0; i < subviewsToInclude.Count; i++)
+					{
+						if (node[i] != GetYogaNode(subviewsToInclude[i]))
+						{
+							shouldReconstructChildList = true;
+							break;
+						}
+					}
+				}
+
+				if (shouldReconstructChildList)
+				{
+					RemoveAllChildren(node);
+
+					for (int i = 0; i < subviewsToInclude.Count; i++)
+					{
+						var subView = subviewsToInclude[i];
+						node.Insert(i, subView.GetYogaNode());
+						AttachNodesFromViewHierachy(subView);
+					}
+				}
+			}
+		}
+
+		static void RemoveAllChildren(YogaNode node)
+		{
+			if (node == null)
+				return;
+
+			while (node.Count > 0)
+			{
+				node.Clear();
+			}
+		}
+
+
+		[DllImport("/usr/lib/libobjc.dylib")]
+		static extern void objc_setAssociatedObject(IntPtr @object, IntPtr key, IntPtr value, AssociationPolicy policy);
+
+		[DllImport("/usr/lib/libobjc.dylib")]
+		static extern IntPtr objc_getAssociatedObject(IntPtr @object, IntPtr key);
+
+		enum AssociationPolicy
+		{
+			ASSIGN = 0,
+			RETAIN_NONATOMIC = 1,
+			COPY_NONATOMIC = 3,
+			RETAIN = 01401,
+			COPY = 01403,
+		}
+	}
+
+	class YGNodeBridge : NSObject
+	{
+		bool disposed;
+		internal WeakReference<UIView> viewRef;
+		internal YogaNode node;
+		public YGNodeBridge()
+		{
+			node = new YogaNode();
+		}
+
+		public void SetContext(UIView view)
+		{
+			viewRef = new WeakReference<UIView>(view);
+			YogaKit.Bridges.Add(node, this);
+		}
+
+		protected override void Dispose(bool disposing)
+		{
+			if (disposing && !disposed)
+			{
+				disposed = true;
+				YogaKit.Bridges.Remove(node);
+				viewRef = null;
+				node = null;
+			}
+			base.Dispose(disposing);
+		}
+	}
+}