[Java.Base, generator] Bind all of package java.lang (#966)

Context: bc5bcf4

Bind all classes and interfaces in the `java.lang` package.

Alter Java array binding, so that instead of `IList<T>`, we get
"direct" Java arrays, e.g.

	namespace Java.Lang {
	    partial class Character {
	        // Previous/Xamarin.Android-like
	        public static int CodePointAt (IList<char>? a, int index);

	        // New/Desktop
	        public static int CodePointAt (JavaCharArray? a, int index);
	    }
	}

Rationale: it *allows* for more efficient JVM :: .NET array copying,
by making copies explicit (to the dev), not implicit.  We can
add an implicit conversion from e.g. `IEnumerable<char>` to
`JavaCharArray` in the future, if deemed useful.

This also impacts method return types, properties, and fields.

Bind the `java.lang.module` package in the namespace
`Java.Lang.Modules`.  This is to avoid a type/namespace conflict
with `java.lang.Module`, bound as `Java.Lang.Module`.

Continue updating `generator` to remove "Android-isms".

Update `Java.Base.csproj` to ignore [warning CS0108][0]:

	Java.Lang.Reflect.IAnnotatedArrayType.cs(15,45):
	warning CS0108: 'IAnnotatedArrayType.AnnotatedOwnerType' hides inherited member
	'IAnnotatedType.AnnotatedOwnerType'. Use the new keyword if hiding was intended.

The problem here is that we have:

	public partial interface IAnnotatedType {
	    // Contains default interface method
	    virtual unsafe IAnnotatedType? AnnotatedOwnerType => …;
	}
	public partial interface IAnnotatedArrayType : IAnnotatedType {
	    // Contains *no* method body; re-abstracted
	    IAnnotatedType? AnnotatedOwnerType {get;}
	}

TODO: figure out how to properly fix this.  `managedOverride`
metadata (5a0e37e) doesn't seem useful to "re-abstract" a default
interface member.

Update `Java.Base.targets` to use `generator --global`.  This is so
that `java.lang.System` can be bound as `Java.Lang.System` without
causing various C# compilation errors due to type lookup.
(Compare to Xamarin.Android's `Java.Lang.JavaSystem`, which got a
`Java*` prefix to avoid these compilation errors.)

Update `JavaInteropCodeGeneratorTests.CreateOptions()` so that C#
features such as default interface methods and nested interface types
are enabled within the unit tests.

TODO:

  * When `generator --codegen-target=JavaInterop1` is used, all the
    language features should also be enabled by default.

  * Certain Java Annotation-related types aren't bound in
    JavaInterop1, vs. XAJavaInterop1.  Revisit this.

  * "Revisit" use of `JNIEnv.ToLocalJniHandle()` in Xamarin.Android
    bindings, and it's outright removal in JavaInterop1 bindings.
    @jonpryor *thinks* the `JNIENv.ToLocalJniHandle(v)` was introduced
    "in case" `v` would be collected by the GC "during" a JNI call.
    Use of `GC.KeepAlive()` (1f21f38, da73d6a), would be a better
    solution, but also requires auditing `generator` output.

  * Bind the rest of `java.base.jmod` (bc5bcf4).

[0]: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-messages/cs0108

Author: jonpryor

src/Java.Base/Java.Base.csproj

@@ -4,7 +4,8 @@
     <TargetFrameworks>net6.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Nullable>enable</Nullable>
-    <NoWarn>$(NoWarn);8764</NoWarn>
+    <!-- TODO: CS0108 is due to e.g. interfaces re-abstracting default interface methods -->
+    <NoWarn>$(NoWarn);8764;CS0108</NoWarn>
     <Version>$(JICoreLibVersion)</Version>
   </PropertyGroup>
 

src/Java.Base/Java.Base.targets

@@ -44,7 +44,7 @@
     <MakeDir Directories="$(IntermediateOutputPath)mcw" />
     <PropertyGroup>
       <Generator>"$(GeneratorPath)"</Generator>
-      <_GenFlags>--public</_GenFlags>
+      <_GenFlags>--public --global</_GenFlags>
       <_Out>-o "$(IntermediateOutputPath)mcw"</_Out>
       <_Codegen>--codegen-target=JavaInterop1</_Codegen>
       <_Fixup>--fixup=Transforms/Metadata.xml</_Fixup>

src/Java.Base/Java.Lang/ICharSequence.cs

@@ -0,0 +1,20 @@
+namespace Java.Lang {
+
+	public static partial class ICharSequenceExtensions {
+
+		public static ICharSequence[]? ToCharSequenceArray (this string?[]? values)
+		{
+			if (values == null) {
+				return null;
+			}
+			var array = new ICharSequence [values.Length];
+			for (int i = 0; i < values.Length; ++i) {
+				if (values [i] == null) {
+					continue;
+				}
+				array [i] = new Java.Lang.String (values [i]);
+			}
+			return array;
+		}
+	}
+}

src/Java.Base/Java.Lang/String.cs

@@ -0,0 +1,9 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using Java.Interop;
+
+namespace Java.Lang {
+	public partial class String : IEnumerable, IEnumerable<char> {
+	}
+}

src/Java.Base/Java.Lang/StringBuffer.cs

@@ -0,0 +1,8 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Java.Lang {
+	partial class StringBuffer : IEnumerable, IEnumerable<char> {
+	}
+}

src/Java.Base/Java.Lang/StringBuilder.cs

@@ -0,0 +1,8 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Java.Lang {
+	partial class StringBuilder : IEnumerable, IEnumerable<char> {
+	}
+}

src/Java.Base/Transforms/Metadata.xml

@@ -2,16 +2,22 @@
   <!-- For now, just bind java.lang.* -->
   <remove-node path="//api/package[not(starts-with(@name, 'java.lang'))]" />
 
-  <!-- For now, just bind Class, Object, Throwable -->
-  <remove-node path="//api/package/interface" />
-  <remove-node path="//api/package/class[not(@name = 'Object'
-      or @name = 'BootstrapMethodError'
-      or @name = 'Class'
-      or @name = 'Math'
-      or @name = 'Number'
-      or @name = 'Throwable'
-    )]"
-  />
+  <!-- Type / Namespace conflicts -->
+  <ns-replace source="java.lang.module" replacement="Java.Lang.Modules" />
 
-  <attr path="/api/package[@name='java.lang']/class[@name='Object']/method[@name='finalize']" name="managedName">JavaFinalize</attr>
+  <!-- Bind `Object.finalize()` as `Object.JavaFinalize()` -->
+  <attr path="/api/package[@name='java.lang']//method[@name='finalize' and count(parameter)=0]" name="managedName">JavaFinalize</attr>
+  <!-- warning CS0672: Member 'Enum.JavaFinalize()' overrides obsolete member 'Object.JavaFinalize()'. Add the Obsolete attribute to 'Enum.JavaFinalize()'. -->
+  <attr path="/api/package[@name='java.lang']/class[@name='Enum']/method[@name='finalize' and count(parameter)=0]" name="deprecated">deprecated</attr>
+
+  <!-- AbstractStringBuilder is package-private; fixity fix -->
+  <remove-node path="//api/package[@name='java.lang']/class[@name='AbstractStringBuilder']" />
+
+  <attr path="/api/package[@name='java.lang']/class[@name='StringBuilder']" name="extends">java.lang.Object</attr>
+  <remove-node path="//api/package[@name='java.lang']/class[@name='StringBuilder']/method[@jni-return='Ljava/lang/AbstractStringBuilder;']" />
+  <remove-node path="//api/package[@name='java.lang']/class[@name='StringBuilder']/method[@jni-return='Ljava/lang/Appendable;']" />
+
+  <attr path="/api/package[@name='java.lang']/class[@name='StringBuffer']" name="extends">java.lang.Object</attr>
+  <remove-node path="//api/package[@name='java.lang']/class[@name='StringBuffer']/method[@jni-return='Ljava/lang/AbstractStringBuilder;']" />
+  <remove-node path="//api/package[@name='java.lang']/class[@name='StringBuffer']/method[@jni-return='Ljava/lang/Appendable;']" />
 </metadata>

tests/generator-Tests/Integration-Tests/Arrays.cs

@@ -6,8 +6,6 @@ namespace generatortests
 	[TestFixture]
 	public class Arrays : BaseGeneratorTest
 	{
-		protected override bool TryJavaInterop1 => false;
-
 		[Test]
 		public void GeneratedOK ()
 		{

tests/generator-Tests/Integration-Tests/Compiler.cs

@@ -71,7 +71,7 @@ public static Assembly Compile (Xamarin.Android.Binder.CodeGeneratorOptions opti
 			var references = referencePaths.Select (p => MetadataReference.CreateFromFile (p)).ToArray ();
 
 			string testCommandLine =
-				$"csc \"-out:{Path.GetFileName (assemblyFileName)}\" " +
+				$"csc -noconfig -nostdlib \"-out:{Path.GetFileName (assemblyFileName)}\" " +
 				$"-unsafe -t:library " +
 				string.Join (" ", preprocessorSymbols.Select (p => $"\"-define:{p}\"")) + " " +
 				string.Join (" ", referencePaths.Select (p => $"\"-r:{p}\"")) + " " +

tests/generator-Tests/Unit-Tests/CodeGeneratorExpectedResults/JavaInterop1/WriteClass.txt

@@ -24,7 +24,7 @@ public partial class MyClass {
 	}
 
 	// Metadata.xml XPath constructor reference: path="/api/package[@name='java.code']/class[@name='MyClass']/constructor[@name='MyClass' and count(parameter)=1 and parameter[1][@type='java.lang.String']]"
-	unsafe MyClass (string p0) : base (ref *InvalidJniObjectReference, JniObjectReferenceOptions.None)
+	unsafe MyClass (string? p0) : base (ref *InvalidJniObjectReference, JniObjectReferenceOptions.None)
 	{
 		const string __id = "(Ljava/lang/String;)V";
 
@@ -65,7 +65,7 @@ public partial class MyClass {
 		}
 	}
 
-	public virtual unsafe string Key {
+	public virtual unsafe string? Key {
 		// Metadata.xml XPath method reference: path="/api/package[@name='java.code']/class[@name='MyClass']/method[@name='get_Key' and count(parameter)=0]"
 		get {
 			const string __id = "get_Key.()Ljava/lang/String;";
@@ -120,7 +120,7 @@ public partial class MyClass {
 	}
 
 	// Metadata.xml XPath method reference: path="/api/package[@name='java.code']/class[@name='MyClass']/method[@name='GetCountForKey' and count(parameter)=1 and parameter[1][@type='java.lang.String']]"
-	public virtual unsafe int GetCountForKey (string key)
+	public virtual unsafe int GetCountForKey (string? key)
 	{
 		const string __id = "GetCountForKey.(Ljava/lang/String;)I";
 		var native_key = global::Java.Interop.JniEnvironment.Strings.NewString (key);
@@ -135,7 +135,7 @@ public partial class MyClass {
 	}
 
 	// Metadata.xml XPath method reference: path="/api/package[@name='java.code']/class[@name='MyClass']/method[@name='Key' and count(parameter)=0]"
-	public virtual unsafe string Key ()
+	public virtual unsafe string? Key ()
 	{
 		const string __id = "Key.()Ljava/lang/String;";
 		try {