[jcw-gen] Use + for nested types, not / (#1304)

Context: dotnet/android#9747
Context: https://discord.com/channels/732297728826277939/732297837953679412/1336353039031734352
Context: https://discord.com/channels/732297728826277939/732297837953679412/1336358257769316372
Context: #1302
Context: dotnet/android#9750
The `[Register]` attribute provides "connector method" names, and for
interface methods this will also include the name of the type which
declares the method, which itself may be in a nested type:
namespace Android.App {
public partial class Application {
public partial interface IActivityLifecycleCallbacks : IJavaObject, IJavaPeerable {
[Register (
name: "onActivityCreated",
signature: "(Landroid/app/Activity;Landroid/os/Bundle;)V",
connector: "GetOnActivityCreated_Landroid_app_Activity_Landroid_os_Bundle_Handler:Android.App.Application/IActivityLifecycleCallbacksInvoker, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null")]
void OnActivityCreated (Android.App.Activity activity, Android.OS.Bundle? savedInstanceState);
// …
}
}
}
The `connector` value is copied as-is into Java Callable Wrappers,
as part of the `__md_methods` value and `Runtime.register()` call.
Given the C# type:
partial class MauiApplication : Application {
partial class ActivityLifecycleCallbacks : Java.Lang.Object, Application.IActivityLifecycleCallbacks {
public void OnActivityCreated (Activity activity, Bundle? savedInstanceState) => …
}
}
then `Java.Interop.Tools.JavaCallableWrappers` will produce:
// Java Callable Wrapper
/* partial */ class MauiApplication_ActivityLifecycleCallbacks
{
public static final String __md_methods;
static {
__md_methods =
// …
"n_onActivityCreated:(Landroid/app/Activity;Landroid/os/Bundle;)V:GetOnActivityCreated_Landroid_app_Activity_Landroid_os_Bundle_Handler:Android.App.Application/IActivityLifecycleCallbacksInvoker, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null\n" +
// …
"";
mono.android.Runtime.register ("Microsoft.Maui.MauiApplication+ActivityLifecycleCallbacks, Microsoft.Maui", MauiApplication_ActivityLifecycleCallbacks.class, __md_methods);
}
}
The `signature` and `connector` values from the `[Register(…)]` on
the method declaration are copied as-is into `__md_methods`.
As the `connector` value contains a `/`, `__md_methods` does as well.
This has worked fine for nearly 15+ years…on Mono/MonoVM.
This *fails* on NativeAOT and CoreCLR, as:
Type.GetType ("Android.App.Application/IActivityLifecycleCallbacksInvoker, Mono.Android, …", throwOnError:true)
fails with:
TypeLoadException: Could not resolve type 'Android.App.Application/IActivityLifecycleCallbacksInvoker' in assembly 'Mono.Android, …'.
The reason for the failure is that when using Reflection APIs such as
`Type.GetType()`, the [`Type.AssemblyQualifiedName` grammar][0] must
be followed, and that grammar uses `+` to "Precede a nested class",
*not* `/`. (`/` isn't even in the Reflection grammar!)
(Aside: where does `/` come from then? It's the *IL* separator for
nested types!)
For eventual CoreCLR and NativeAOT support, then, we need to replace
`/` with `+` *somewhere* before it hits `Type.GetType()`.
There are (at least?) three places to do so:
1. Within `JniRuntime.JniTypeManager.RegisterNativeMembers()` or
equivalent override.
2. Within `generator`, updating the contents of `[Register]`.
3. Within `Java.Interop.Tools.JavaCallableWrappers`.
(1) is rejected out of hand as it would be additional work done on-
device at runtime. Why do that if we don't need to?
(2) was attempted in #1302 & dotnet/android#9750.
It turned into a bit of a boondoggle, because there are lots of
linker steps which interpret the `connector` value on `[Register]`,
and it "just worked" that the `connector` value contained IL names,
as the linker steps deal in IL! Trying to update `connector` to
instead contain Reflection syntax required finding all the places in
the linker that used `connector` values, which was tedious & brittle.
"Just" (2) is also inadequate, as it would require new binding
assemblies to take advantage of, so (2) *also* needed (3).
Which brings us to (3), the current approach: *don't* alter the
semantics of the `connect` value within `[Register]`, and instead
require that `Java.Interop.Tools.JavaCallableWrappers` replace all
instances of `/` with `+` within `__md_methods`. This is needed
*anyway*, for compatibility with existing bindings, and also avoids
lots of pain that (2) encountered.
With this approach, `generator` output is unchanged, and
`jcw-gen` output for `MauiApplication.ActivityLifecycleCallbacks`
becomes:
// Java Callable Wrapper
/* partial */ class MauiApplication_ActivityLifecycleCallbacks
{
public static final String __md_methods;
static {
__md_methods =
// …
"n_onActivityCreated:(Landroid/app/Activity;Landroid/os/Bundle;)V:GetOnActivityCreated_Landroid_app_Activity_Landroid_os_Bundle_Handler:Android.App.Application+IActivityLifecycleCallbacksInvoker, Mono.Android, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null\n" +
// …
"";
mono.android.Runtime.register ("Microsoft.Maui.MauiApplication+ActivityLifecycleCallbacks, Microsoft.Maui", MauiApplication_ActivityLifecycleCallbacks.class, __md_methods);
}
}
[0]: https://learn.microsoft.com/en-us/dotnet/api/system.type.assemblyqualifiedname?view=net-9.0#remarks

Author: jonpryor

src/Java.Interop.Tools.JavaCallableWrappers/Java.Interop.Tools.JavaCallableWrappers.Adapters/CecilImporter.cs

@@ -269,7 +269,7 @@ static CallableWrapperMethod CreateMethod (MethodDefinition methodDefinition, Ca
 staticCallableWrapperMethodCreateMethod(stringname,CallableWrapperTypedeclaringType,string?signature,string?connector,string?managedParameters,string?outerType,string?superCall)
 {
 signature=signature??thrownewArgumentNullException("`connector` cannot be null.",nameof(connector));
-varmethod_name="n_"+name+":"+signature+":"+connector;
+varmethod_name="n_"+name+":"+signature+":"+connector?.Replace('/','+');
 
 varmethod=newCallableWrapperMethod(declaringType,name,method_name,signature);
 

src/Java.Interop.Tools.TypeNameMappings/Java.Interop.Tools.TypeNameMappings/JavaNativeTypeManager.cs

@@ -150,7 +150,7 @@ static string ToCliTypePart (string part)
 for(inti=0;i<parts.Length;++i){
 parts[i]=ToPascalCase(parts[i],1);
 }
-returnstring.Join("/",parts);
+returnstring.Join("+",parts);
 }
 
 staticstringToPascalCase(stringvalue,intminLength)

tests/Java.Interop.Export-Tests/Java.Interop.Export-Tests.csproj

@@ -26,6 +26,10 @@
  <ProjectReferenceInclude="..\..\src\Java.Interop.Export\Java.Interop.Export.csproj" />
  <ProjectReferenceInclude="..\..\src\Java.Runtime.Environment\Java.Runtime.Environment.csproj" />
  <ProjectReferenceInclude="..\TestJVM\TestJVM.csproj" />
+ <ProjectReference
+Include="..\..\tools\jcw-gen\jcw-gen.csproj"
+ReferenceOutputAssembly="false"
+ />
  </ItemGroup>
 
  <ItemGroup>

tests/Java.Interop.Tools.JavaCallableWrappers-Tests/Java.Interop.Tools.JavaCallableWrappers/JavaCallableWrapperGeneratorTests.cs

@@ -104,6 +104,55 @@ public void monodroidClearReferences ()
 Assert.AreEqual(expected,actual);
 }
 
+[Test]
+publicvoidGenerateTypeMentioningNestedInvoker()
+{
+varactual=Generate(typeof(ApplicationName.ActivityLifecycleCallbacks));
+varexpected="""
+package application;
+
+
+public class Name_ActivityLifecycleCallbacks
+	extends java.lang.Object
+	implements
+ mono.android.IGCUserPeer,
+ java.lang.Object
+{
+/** @hide */
+	public static final String __md_methods;
+	static {
+ __md_methods = 
+ "n_onActivityCreated:(Landroid/app/Activity;Landroid/os/Bundle;)V:GetOnActivityCreated_Landroid_app_Activity_Landroid_os_Bundle_Handler:Android.App.Application+IActivityLifecycleCallbacksInvoker, Mono.Android\n" +
+ "";
+ mono.android.Runtime.register ("Xamarin.Android.ToolsTests.ApplicationName+ActivityLifecycleCallbacks, Java.Interop.Tools.JavaCallableWrappers-Tests", Name_ActivityLifecycleCallbacks.class, __md_methods);
+	}
+
+	public void onActivityCreated (android.app.Activity p0, android.os.Bundle p1)
+	{
+ n_onActivityCreated (p0, p1);
+	}
+
+	private native void n_onActivityCreated (android.app.Activity p0, android.os.Bundle p1);
+
+	private java.util.ArrayList refList;
+	public void monodroidAddReference (java.lang.Object obj)
+	{
+ if (refList == null)
+ refList = new java.util.ArrayList ();
+ refList.add (obj);
+	}
+
+	public void monodroidClearReferences ()
+	{
+ if (refList != null)
+ refList.clear ();
+	}
+}
+
+""";
+Assert.AreEqual(expected,actual);
+}
+
 staticstringGenerate(Typetype,stringapplicationJavaClass=null,stringmonoRuntimeInit=null,JavaPeerStylestyle=JavaPeerStyle.XAJavaInterop1)
 {
 varreader_options=newCallableWrapperReaderOptions{

tests/Java.Interop.Tools.JavaCallableWrappers-Tests/Java.Interop.Tools.JavaCallableWrappers/SupportDeclarations.cs

@@ -22,6 +22,26 @@ class Application : Java.Lang.Object
 protectedvirtualvoidOnCreate()
 {
 }
+
+[Register("android/app/Application$ActivityLifecycleCallbacks",DoNotGenerateAcw=true)]
+publicpartialinterfaceIActivityLifecycleCallbacks{
+[Register(
+name:"onActivityCreated",
+signature:"(Landroid/app/Activity;Landroid/os/Bundle;)V",
+connector:"GetOnActivityCreated_Landroid_app_Activity_Landroid_os_Bundle_Handler:Android.App.Application/IActivityLifecycleCallbacksInvoker, Mono.Android")]
+voidOnActivityCreated(Android.App.Activityactivity,global::Android.OS.BundlesavedInstanceState);
+}
+
+internalclassIActivityLifecycleCallbacksInvoker:Java.Lang.Object,IActivityLifecycleCallbacks{
+staticDelegateGetOnActivityCreated_Landroid_app_Activity_Landroid_os_Bundle_Handler()
+{
+returnnull;
+}
+
+publicvoidOnActivityCreated(Android.App.Activityactivity,global::Android.OS.BundlesavedInstanceState)
+{
+}
+}
 }
 
 [Register("android/app/Activity",DoNotGenerateAcw=true)]
@@ -43,6 +63,14 @@ public virtual void OnCreate (Java.Lang.Object arguments)
 }
 }
 
+namespaceAndroid.OS{
+
+[Register("android/os/Bundle",DoNotGenerateAcw=true)]
+classBundle:Java.Lang.Object
+{
+}
+}
+
 namespaceAndroid.Runtime{
 
 interfaceIJavaObject
@@ -72,6 +100,7 @@ static class SupportDeclarations
 typeof(AbstractClass),
 typeof(ActivityName),
 typeof(ApplicationName),
+typeof(ApplicationName.ActivityLifecycleCallbacks),
 typeof(DefaultName),
 typeof(DefaultName.A),
 typeof(DefaultName.A.B),
@@ -139,6 +168,12 @@ class ActivityName : Java.Lang.Object
 [Application(Name="application.Name")]
 classApplicationName:Application
 {
+publicclassActivityLifecycleCallbacks:Java.Lang.Object,Application.IActivityLifecycleCallbacks
+{
+publicvoidOnActivityCreated(Activityactivity,global::Android.OS.BundlesavedInstanceState)
+{
+}
+}
 }
 
 classIndirectApplication:ApplicationName

tests/Java.Interop.Tools.JavaCallableWrappers-Tests/Java.Interop.Tools.JavaCallableWrappers/TypeNameMapGeneratorTests.cs

@@ -50,7 +50,7 @@ public void WriteJavaToManaged ()
 v.WriteJavaToManaged(o);
 vara=ToArray(o);
 Save(a,"__j2m");
-varlength=190;
+varlength=193;
 varoffset=76;
 vare=
 "version=1\u0000"+
@@ -59,6 +59,7 @@ public void WriteJavaToManaged ()
 "value-offset="+offset+"\u0000"+
 GetJ2MEntryLine(typeof(ActivityName),"activity/Name",offset,length)+
 GetJ2MEntryLine(typeof(ApplicationName),"application/Name",offset,length)+
+GetJ2MEntryLine(typeof(ApplicationName.ActivityLifecycleCallbacks),"application/Name_ActivityLifecycleCallbacks",offset,length)+
 GetJ2MEntryLine(typeof(DefaultName),"crc64197ae30a36756915/DefaultName",offset,length)+
 GetJ2MEntryLine(typeof(DefaultName.A),"crc64197ae30a36756915/DefaultName_A",offset,length)+
 GetJ2MEntryLine(typeof(DefaultName.A.B),"crc64197ae30a36756915/DefaultName_A_B",offset,length)+
@@ -128,8 +129,8 @@ public void WriteManagedToJava ()
 v.WriteManagedToJava(o);
 vara=ToArray(o);
 Save(a,"__m2j");
-varlength=190;
-varoffset=114;
+varlength=193;
+varoffset=117;
 vare=
 "version=1\u0000"+
 $"entry-count={types.Count}\u0000"+
@@ -138,6 +139,7 @@ public void WriteManagedToJava ()
 GetM2JEntryLine(typeof(AbstractClass),"my/AbstractClass",offset,length)+
 GetM2JEntryLine(typeof(AbstractClassInvoker),"my/AbstractClass",offset,length)+
 GetM2JEntryLine(typeof(ActivityName),"activity/Name",offset,length)+
+GetM2JEntryLine(typeof(ApplicationName.ActivityLifecycleCallbacks),"application/Name_ActivityLifecycleCallbacks",offset,length)+
 GetM2JEntryLine(typeof(ApplicationName),"application/Name",offset,length)+
 GetM2JEntryLine(typeof(DefaultName.A.B),"crc64197ae30a36756915/DefaultName_A_B",offset,length)+
 GetM2JEntryLine(typeof(DefaultName.A),"crc64197ae30a36756915/DefaultName_A",offset,length)+

tools/generator/Java.Interop.Tools.Generator.ObjectModel/ClassGen.cs

@@ -181,7 +181,7 @@ public static void GenerateTypeRegistrations (CodeGenerationOptions opt, Generat
 intls=reg.Key.LastIndexOf('/');
 stringpackage=ls>=0?reg.Key.Substring(0,ls):"";
 
-if(JavaNativeTypeManager.ToCliType(reg.Key)==reg.Value)
+if(JavaNativeTypeManager.ToCliType(reg.Key)==reg.Value.Replace('/','+'))
 continue;
 if(!mapping.TryGetValue(package,outvarv))
 mapping.Add(package,v=newList<KeyValuePair<string,string>>());