[generator] Avoid non-blittable types in native callback methods

Author: jpobst

tests/generator-Tests/Unit-Tests/BlittableTypeTests.cs

@@ -0,0 +1,77 @@
+using System;
+using MonoDroid.Generation;
+using NUnit.Framework;
+using Xamarin.Android.Binder;
+
+namespace generatortests;
+
+[TestFixture]
+class BlittableTypeTests : CodeGeneratorTestBase
+{
+	protected override CodeGenerationTarget Target => CodeGenerationTarget.XAJavaInterop1;
+
+	[Test]
+	public void MethodWithBoolReturnType ()
+	{
+		var klass = new TestClass ("Object", "java.code.MyClass");
+		var method = SupportTypeBuilder.CreateMethod (klass, "IsEmpty", options, "boolean");
+
+		klass.Methods.Add (method);
+
+		var actual = GetGeneratedTypeOutput (klass);
+
+		// Return type should be byte
+		Assert.That (actual, Contains.Substring ("static byte n_IsEmpty"));
+
+		// Return statement should convert to 0 or 1
+		Assert.That (actual, Contains.Substring ("return __this.IsEmpty () ? 1 : 0"));
+
+		// Ensure the marshal delegate is byte
+		Assert.That (actual, Contains.Substring ("new _JniMarshal_PP_B"));
+		Assert.That (actual, Does.Not.Contains ("new _JniMarshal_PP_Z"));
+	}
+
+	[Test]
+	public void MethodWithBoolParameter ()
+	{
+		var klass = new TestClass ("Object", "java.code.MyClass");
+		var method = SupportTypeBuilder.CreateMethod (klass, "SetEmpty", options, "void", parameters: new Parameter ("value", "boolean", "bool", false));
+
+		klass.Methods.Add (method);
+
+		var actual = GetGeneratedTypeOutput (klass);
+
+		// Method parameter should be byte
+		Assert.That (actual, Contains.Substring ("static void n_SetEmpty_Z (IntPtr jnienv, IntPtr native__this, byte native_value)"));
+
+		// Method should convert from 0 or 1
+		Assert.That (actual, Contains.Substring ("var value = native_value != 0;"));
+
+		// Ensure the marshal delegate is byte
+		Assert.That (actual, Contains.Substring ("new _JniMarshal_PPB_V"));
+		Assert.That (actual, Does.Not.Contains ("new _JniMarshal_PPZ_V"));
+	}
+
+	[Test]
+	public void BoolProperty ()
+	{
+		var klass = SupportTypeBuilder.CreateClassWithProperty ("MyClass", "com.example.myClass", "IsEmpty", "boolean", options);
+		var actual = GetGeneratedTypeOutput (klass);
+
+		// Getter return type should be byte
+		Assert.That (actual, Contains.Substring ("static byte n_get_IsEmpty"));
+
+		// Getter return statement should convert to 0 or 1
+		Assert.That (actual, Contains.Substring ("return __this.IsEmpty ? 1 : 0"));
+
+		// Setter parameter should be byte
+		Assert.That (actual, Contains.Substring ("static void n_set_IsEmpty_Z (IntPtr jnienv, IntPtr native__this, byte native_value)"));
+
+		// Setter should convert from 0 or 1
+		Assert.That (actual, Contains.Substring ("var value = native_value != 0;"));
+
+		// Ensure the marshal delegate is byte
+		Assert.That (actual, Contains.Substring ("new _JniMarshal_PP_B"));
+		Assert.That (actual, Does.Not.Contains ("new _JniMarshal_PP_Z"));
+	}
+}

tests/generator-Tests/Unit-Tests/CodeGeneratorTestBase.cs

@@ -131,5 +131,14 @@ protected static string GetAssertionMessage (string header, string expected, str
 				$"Expected:\n```\n{expected}\n```\n" +
 				$"Actual:\n```\n{actual}\n```";
 		}
+
+		protected string GetGeneratedTypeOutput (GenBase gen)
+		{
+			generator.Context.ContextTypes.Push (gen);
+			generator.WriteType (gen, string.Empty, new GenerationInfo ("", "", "MyAssembly"));
+			generator.Context.ContextTypes.Pop ();
+
+			return writer.ToString ();
+		}
 	}
 }

tools/generator/CodeGenerationOptions.cs

@@ -217,6 +217,7 @@ string GetJniTypeCode (ISymbol symbol)
 				case "uint": return "i";
 				case "ulong": return "j";
 				case "ushort": return "s";
+				case "boolean": return "B";     // We marshal boolean (Z) as byte (B)
 			}
 
 			var jni_name = symbol.JniName;

tools/generator/Java.Interop.Tools.Generator.ObjectModel/Symbols/SymbolTable.cs

@@ -57,7 +57,7 @@ public SymbolTable (CodeGenerationTarget target)
 			this.target = target;
 
 			AddType (new SimpleSymbol ("IntPtr.Zero", "void", "void", "V"));
-			AddType (new SimpleSymbol ("false", "boolean", "bool", "Z"));
+			AddType (new SimpleSymbol ("false", "boolean", "bool", "Z", "byte", from_fmt: "{0} != 0", to_fmt: "{0} ? 1 : 0"));
 			AddType (new SimpleSymbol ("0", "byte", "sbyte", "B"));
 			AddType (new SimpleSymbol ("(char)0", "char", "char", "C"));
 			AddType (new SimpleSymbol ("0.0", "double", "double", "D"));