[generator] Strip arity from Cecil imported types. (#450)

Context: #424

One of the issues trying to bind the BouncyCastle-provided
[`bcprov-ext-jdk15on-161.jar.`][0] in #424 is that we write generic
types with invalid signatures:

	public List`1<string> MyProperty { get; set; }

as this is how a Cecil type reference `FullName` is returned.

Since this notation is not useful to us, strip the "arity"
information when reading the assembly.

This results in the proper type syntax:

	public List<string> MyProperty { get; set; }

[0]: https://www.bouncycastle.org/download/bcprov-ext-jdk15on-161.jar

tools/generator/Extensions/ManagedExtensions.cs

@@ -45,6 +45,26 @@ public static IEnumerable<Parameter> GetParameters (this MethodDefinition m, Cus
 				yield return CecilApiImporter.CreateParameter (p, type, rawtype);
 			}
 		}
+
+		public static string StripArity (this string type)
+		{
+			if (string.IsNullOrWhiteSpace (type))
+				return type;
+
+			int tick_index;
+
+			// Need to loop for things like List`1<List`1<string>>
+			while ((tick_index = type.IndexOf ('`')) >= 0) {
+				var less_than_index = type.IndexOf ('<', tick_index);
+
+				if (less_than_index == -1)
+					return type;
+
+				type = type.Substring (0, tick_index) + type.Substring (less_than_index);
+			}
+
+			return type;
+		}
 	}
 #endif
 }

tools/generator/Java.Interop.Tools.Generator.Importers/CecilApiImporter.cs

@@ -93,7 +93,7 @@ public static Field CreateField (FieldDefinition f)
 				IsStatic = f.IsStatic,
 				JavaName = reg_attr != null ? ((string) reg_attr.ConstructorArguments [0].Value).Replace ('/', '.') : f.Name,
 				Name = f.Name,
-				TypeName = f.FieldType.FullNameCorrected (),
+				TypeName = f.FieldType.FullNameCorrected ().StripArity (),
 				Value = f.Constant == null ? null : f.FieldType.FullName == "System.String" ? '"' + f.Constant.ToString () + '"' : f.Constant.ToString (),
 				Visibility = f.IsPublic ? "public" : f.IsFamilyOrAssembly ? "protected internal" : f.IsFamily ? "protected" : f.IsAssembly ? "internal" : "private"
 			};
@@ -181,8 +181,8 @@ public static Method CreateMethod (GenBase declaringType, MethodDefinition m)
 				IsStatic = m.IsStatic,
 				IsVirtual = m.IsVirtual,
 				JavaName = reg_attr != null ? ((string) reg_attr.ConstructorArguments [0].Value) : m.Name,
-				ManagedReturn = m.ReturnType.FullNameCorrected (),
-				Return = m.ReturnType.FullNameCorrected (),
+				ManagedReturn = m.ReturnType.FullNameCorrected ().StripArity (),
+				Return = m.ReturnType.FullNameCorrected ().StripArity (),
 				Visibility = m.Visibility ()
 			};
 
@@ -211,7 +211,7 @@ public static Parameter CreateParameter (ParameterDefinition p, string jnitype,
 			// FIXME: safe to use CLR type name? assuming yes as we often use it in metadatamap.
 			// FIXME: IsSender?
 			var isEnumType = GetGeneratedEnumAttribute (p.CustomAttributes) != null;;
-			return new Parameter (SymbolTable.MangleName (p.Name), jnitype ?? p.ParameterType.FullNameCorrected (), null, isEnumType, rawtype);
+			return new Parameter (SymbolTable.MangleName (p.Name), jnitype ?? p.ParameterType.FullNameCorrected ().StripArity (), null, isEnumType, rawtype);
 		}
 
 		public static Parameter CreateParameter (string managedType, string javaType)

tools/generator/Tests/Unit-Tests/ManagedExtensionsTests.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using MonoDroid.Generation;
+using NUnit.Framework;
+
+namespace generatortests
+{
+	[TestFixture]
+	public class ManagedExtensionsTests
+	{
+		[Test]
+		public void StripArity ()
+		{
+			Assert.AreEqual ("List<string>", "List`1<string>".StripArity ());
+			Assert.AreEqual ("List<List<string>>", "List`10<List`1<string>>".StripArity ());
+			Assert.AreEqual ("List<string>", "List<string>".StripArity ());
+			Assert.AreEqual ("List`1", "List`1".StripArity ());
+			Assert.AreEqual ("L<blah>ist<string>", "L<blah>ist`1<string>".StripArity ());
+			Assert.AreEqual ("List<string>", "List`1`<string>".StripArity ());
+			Assert.AreEqual ("List<<string>", "List`1<<string>".StripArity ());
+			Assert.AreEqual ("List<", "List`<".StripArity ());
+			Assert.AreEqual ("<", "`1<".StripArity ());
+			Assert.AreEqual ("`", "`".StripArity ());
+			Assert.AreEqual (string.Empty, string.Empty.StripArity ());
+			Assert.IsNull ((null as string).StripArity ());
+		}
+	}
+}

tools/generator/Tests/Unit-Tests/ManagedTests.cs

@@ -2,6 +2,7 @@
 using Mono.Cecil;
 using MonoDroid.Generation;
 using NUnit.Framework;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 
@@ -42,6 +43,27 @@ public void UnknownTypes (object unknown) { }
 	public interface IService { }
 }
 
+namespace GenericTestClasses
+{
+	public class MyCollection<T> : List<T>
+	{
+		[Register ("mycollection", "()V", "")]
+		public MyCollection (List<T> p0, List<string> p1)
+		{
+		}
+
+		public List<T> field;
+
+		public Dictionary<string, T> field2;
+
+		[Register ("dostuff", "()V", "")]
+		public Dictionary<T, List<string>> DoStuff (IEnumerable<KeyValuePair<T, List<List<T>>>> p)
+		{
+			return new Dictionary<T, List<string>> ();
+		}
+	}
+}
+
 namespace generatortests
 {
 	[TestFixture]
@@ -206,5 +228,27 @@ public void Interface ()
 			Assert.AreEqual ("com.mypackage.service", @interface.JavaName);
 			Assert.AreEqual ("Lcom/mypackage/service;", @interface.JniName);
 		}
+
+		[Test]
+		public void StripArity ()
+		{
+			var @class = CecilApiImporter.CreateClass (module.GetType ("GenericTestClasses.MyCollection`1"), options);
+
+			// Class (Leave Arity on types)
+			Assert.AreEqual ("GenericTestClasses.MyCollection`1", @class.FullName);
+
+			// Constructor
+			Assert.AreEqual ("System.Collections.Generic.List<T>", @class.Ctors [0].Parameters [0].RawNativeType);
+			Assert.AreEqual ("System.Collections.Generic.List<System.String>", @class.Ctors [0].Parameters [1].RawNativeType);
+
+			// Field
+			Assert.AreEqual ("System.Collections.Generic.List<T>", @class.Fields [0].TypeName);
+			Assert.AreEqual ("System.Collections.Generic.Dictionary<System.String,T>", @class.Fields [1].TypeName);
+
+			// Method
+			Assert.AreEqual ("System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<T,System.Collections.Generic.List<System.Collections.Generic.List<T>>>>", @class.Methods [0].Parameters [0].RawNativeType);
+			Assert.AreEqual ("System.Collections.Generic.Dictionary<T,System.Collections.Generic.List<System.String>>", @class.Methods [0].ReturnType);
+			Assert.AreEqual ("System.Collections.Generic.Dictionary<T,System.Collections.Generic.List<System.String>>", @class.Methods [0].ManagedReturn);
+		}
 	}
 }

tools/generator/Tests/generator-Tests.csproj

@@ -74,6 +74,7 @@
     <Compile Include="Unit-Tests\AdjusterTests.cs" />
     <Compile Include="Unit-Tests\DefaultInterfaceMethodsTests.cs" />
     <Compile Include="Unit-Tests\EnumGeneratorTests.cs" />
+    <Compile Include="Unit-Tests\ManagedExtensionsTests.cs" />
     <Compile Include="Unit-Tests\ManagedTests.cs" />
     <Compile Include="Unit-Tests\SupportTypes.cs" />
     <Compile Include="Unit-Tests\TestExtensions.cs" />