[XamlC] compile ThicknessTypeConverter (#603)

2 files changed, 52 insertions, 0 deletions

diff --git a/Xamarin.Forms.Build.Tasks/CompiledConverters/ThicknessTypeConverter.cs b/Xamarin.Forms.Build.Tasks/CompiledConverters/ThicknessTypeConverter.cs
new file mode 100644
index 00000000..e16a8b01
--- /dev/null
+++ b/Xamarin.Forms.Build.Tasks/CompiledConverters/ThicknessTypeConverter.cs
@@ -0,0 +1,51 @@
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+
+using Xamarin.Forms.Xaml;
+
+namespace Xamarin.Forms.Core.XamlC
+{
+	class ThicknessTypeConverter : ICompiledTypeConverter
+	{
+		public IEnumerable<Instruction> ConvertFromString(string value, ModuleDefinition module, BaseNode node)
+		{
+			if (!string.IsNullOrEmpty(value)) {
+				double l, t, r, b;
+				var thickness = value.Split(',');
+				switch (thickness.Length) {
+				case 1:
+					if (double.TryParse(thickness[0], NumberStyles.Number, CultureInfo.InvariantCulture, out l))
+						return GenerateIL(module, l);
+					break;
+				case 2:
+					if (double.TryParse(thickness[0], NumberStyles.Number, CultureInfo.InvariantCulture, out l) &&
+					    double.TryParse(thickness[1], NumberStyles.Number, CultureInfo.InvariantCulture, out t))
+						return GenerateIL(module, l, t);
+					break;
+				case 4:
+					if (double.TryParse(thickness[0], NumberStyles.Number, CultureInfo.InvariantCulture, out l) &&
+					    double.TryParse(thickness[1], NumberStyles.Number, CultureInfo.InvariantCulture, out t) &&
+						double.TryParse(thickness[2], NumberStyles.Number, CultureInfo.InvariantCulture, out r) &&
+					    double.TryParse(thickness[3], NumberStyles.Number, CultureInfo.InvariantCulture, out b))
+						return GenerateIL(module, l, t, r, b);
+					break;
+				}
+			}
+			throw new XamlParseException($"Cannot convert \"{value}\" into {typeof(Thickness)}", node);
+		}
+
+		IEnumerable<Instruction> GenerateIL(ModuleDefinition module, params double[] args)
+		{
+			foreach (var d in args)
+				yield return Instruction.Create(OpCodes.Ldc_R8, d);
+			var thicknessCtor = module.Import(typeof(Thickness)).Resolve().Methods.FirstOrDefault(md => md.IsConstructor && md.Parameters.Count == args.Length);
+			var thicknessCtorRef = module.Import(thicknessCtor);
+			yield return Instruction.Create(OpCodes.Newobj, thicknessCtorRef);
+		}
+	}
+	
+}
\ No newline at end of file
diff --git a/Xamarin.Forms.Build.Tasks/Xamarin.Forms.Build.Tasks.csproj b/Xamarin.Forms.Build.Tasks/Xamarin.Forms.Build.Tasks.csproj
index 9507ea3c..1ccace2b 100644
--- a/Xamarin.Forms.Build.Tasks/Xamarin.Forms.Build.Tasks.csproj
+++ b/Xamarin.Forms.Build.Tasks/Xamarin.Forms.Build.Tasks.csproj
@@ -102,6 +102,7 @@
     <Compile Include="XamlTask.cs" />
     <Compile Include="CompiledMarkupExtensions\ArrayExtension.cs" />
     <Compile Include="CompiledConverters\ConstraintTypeConverter.cs" />
+    <Compile Include="CompiledConverters\ThicknessTypeConverter.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <Target Name="AfterBuild">