[XamlC] Implement IValueProvider.PropertyType (#345)

1 files changed, 61 insertions, 0 deletions

diff --git a/Xamarin.Forms.Build.Tasks/BindablePropertyReferenceExtensions.cs b/Xamarin.Forms.Build.Tasks/BindablePropertyReferenceExtensions.cs
new file mode 100644
index 00000000..159bbf5f
--- /dev/null
+++ b/Xamarin.Forms.Build.Tasks/BindablePropertyReferenceExtensions.cs
@@ -0,0 +1,61 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Xml;
+
+using Mono.Cecil;
+
+using Xamarin.Forms.Xaml;
+
+namespace Xamarin.Forms.Build.Tasks
+{
+	static class BindablePropertyReferenceExtensions
+	{
+		public static TypeReference GetBindablePropertyType(this FieldReference bpRef, IXmlLineInfo iXmlLineInfo, ModuleDefinition module)
+		{
+			if (!bpRef.Name.EndsWith("Property", StringComparison.InvariantCulture))
+				throw new XamlParseException($"The name of the bindable property {bpRef.Name} does not ends with \"Property\". This is the kind of convention the world is build upon, a bit like Planck's constant.", iXmlLineInfo);
+			var bpName = bpRef.Name.Substring(0, bpRef.Name.Length - 8);
+			var owner = bpRef.DeclaringType;
+			TypeReference _;
+
+			var getter = owner.GetProperty(pd => pd.Name == bpName, out _)?.GetMethod;
+			if (getter == null || getter.IsStatic || !getter.IsPublic)
+				getter = null;
+			getter = getter ?? owner.GetMethods(md => md.Name == $"Get{bpName}" &&
+												md.IsStatic &&
+												md.IsPublic &&
+												md.Parameters.Count == 1 &&
+												md.Parameters [0].ParameterType.FullName == "Xamarin.Forms.BindableObject", module).SingleOrDefault()?.Item1;
+
+			if (getter == null)
+				throw new XamlParseException($"Missing a public static Get{bpName} or a public instance property getter for the attached property \"{bpRef.DeclaringType}.{bpRef.Name}\"", iXmlLineInfo);
+			return getter.ReturnType;
+		}
+
+		public static TypeReference GetBindablePropertyTypeConverter(this FieldReference bpRef, ModuleDefinition module)
+		{
+			TypeReference _;
+			var owner = bpRef.DeclaringType;
+			var bpName = bpRef.Name.EndsWith("Property", StringComparison.Ordinal) ? bpRef.Name.Substring(0, bpRef.Name.Length - 8) : bpRef.Name;
+			var property = owner.GetProperty(pd => pd.Name == bpName, out _);
+			var staticGetter = owner.GetMethods(md => md.Name == $"Get{bpName}" &&
+												md.IsStatic &&
+												md.IsPublic &&
+												md.Parameters.Count == 1 &&
+												md.Parameters [0].ParameterType.FullName == "Xamarin.Forms.BindableObject", module).SingleOrDefault()?.Item1;
+
+			var attributes = new List<CustomAttribute>();
+			if (property != null && property.HasCustomAttributes)
+				attributes.AddRange(property.CustomAttributes);
+			if (property != null && property.PropertyType.Resolve().HasCustomAttributes)
+				attributes.AddRange(property.PropertyType.Resolve().CustomAttributes);
+			if (staticGetter != null && staticGetter.HasCustomAttributes)
+				attributes.AddRange(staticGetter.CustomAttributes);
+			if (staticGetter != null && staticGetter.ReturnType.Resolve().HasCustomAttributes)
+				attributes.AddRange(staticGetter.ReturnType.Resolve().CustomAttributes);
+
+			return attributes.FirstOrDefault(cad => TypeConverterAttribute.TypeConvertersType.Contains(cad.AttributeType.FullName))?.ConstructorArguments [0].Value as TypeReference;
+		}
+	}
+}
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