[jnigen] Refactor type classes (#1591)

* Make all type class methods and fields internal
* Use better import prefixes
* Rename `castTo` to `as`
* Relax renaming keywords
* Rename to `MethodInvocation`
* Rename typeclass of `Foo` to `$Foo$Type`
* Make generic type parameters internal

Author: HosseinYousefi

pkgs/jni/example/lib/main.dart

@@ -54,7 +54,7 @@ int randomUsingEnv(int n) => using((arena) {
 double randomDouble() {
   final math = JClass.forName("java/lang/Math");
   final random =
-      math.staticMethodId("random", "()D").call(math, const jdoubleType(), []);
+      math.staticMethodId("random", "()D").call(math, jdouble.type, []);
   math.release();
   return random;
 }
@@ -63,7 +63,7 @@ int uptime() {
   return JClass.forName("android/os/SystemClock").use(
     (systemClock) => systemClock
         .staticMethodId("uptimeMillis", "()J")
-        .call(systemClock, const jlongType(), []),
+        .call(systemClock, jlong.type, []),
   );
 }
 
@@ -74,9 +74,8 @@ String backAndForth() {
 }
 
 void quit() {
-  JObject.fromReference(Jni.getCurrentActivity()).use((ac) => ac.jClass
-      .instanceMethodId("finish", "()V")
-      .call(ac, const jvoidType(), []));
+  JObject.fromReference(Jni.getCurrentActivity()).use((ac) =>
+      ac.jClass.instanceMethodId("finish", "()V").call(ac, jvoid.type, []));
 }
 
 void showToast(String text) {
@@ -94,14 +93,14 @@ void showToast(String text) {
       '(Landroid/app/Activity;Landroid/content/Context;'
           'Ljava/lang/CharSequence;I)'
           'Lcom/github/dart_lang/jni_example/Toaster;');
-  final toaster = makeText.call(toasterClass, const JObjectType(), [
+  final toaster = makeText.call(toasterClass, JObject.type, [
     Jni.getCurrentActivity(),
     Jni.getCachedApplicationContext(),
     '😀'.toJString(),
     0,
   ]);
   final show = toasterClass.instanceMethodId('show', '()V');
-  show(toaster, const jvoidType(), []);
+  show(toaster, jvoid.type, []);
 }
 
 void main() {

pkgs/jni/lib/_internal.dart

@@ -8,42 +8,68 @@
 /// not to be used directly.
 library;
 
-import 'dart:ffi' as ffi;
+import 'dart:ffi' as ffi show Int32;
+import 'dart:ffi' hide Int32;
+
+// Exporting all the necessary bits for the generated bindings.
+export 'dart:ffi'
+    show
+        Double,
+        Int64,
+        NativeFunction,
+        NativeFunctionPointer,
+        NativePort,
+        Pointer,
+        VarArgs,
+        Void,
+        nullptr;
+export 'dart:isolate' show RawReceivePort, ReceivePort;
+
+export 'package:meta/meta.dart' show internal;
 
 export 'src/accessors.dart';
 export 'src/jni.dart' show ProtectedJniExtensions;
 export 'src/jreference.dart';
 export 'src/method_invocation.dart';
-export 'src/types.dart' show referenceType;
+export 'src/types.dart'
+    show
+        JAccessible,
+        JArrayElementType,
+        JCallable,
+        JConstructable,
+        JObjType,
+        JType,
+        lowestCommonSuperType,
+        referenceType;
 
 /// Temporary fix for the macOS arm64 varargs problem.
 ///
-/// This integer type is Int32 on all architectures, other than macOS arm64.
-/// Where it is Int64.
-@ffi.AbiSpecificIntegerMapping({
-  ffi.Abi.androidArm: ffi.Int32(),
-  ffi.Abi.androidArm64: ffi.Int32(),
-  ffi.Abi.androidIA32: ffi.Int32(),
-  ffi.Abi.androidX64: ffi.Int32(),
-  ffi.Abi.androidRiscv64: ffi.Int32(),
-  ffi.Abi.fuchsiaArm64: ffi.Int32(),
-  ffi.Abi.fuchsiaX64: ffi.Int32(),
-  ffi.Abi.fuchsiaRiscv64: ffi.Int32(),
-  ffi.Abi.iosArm: ffi.Int32(),
-  ffi.Abi.iosArm64: ffi.Int32(),
-  ffi.Abi.iosX64: ffi.Int32(),
-  ffi.Abi.linuxArm: ffi.Int32(),
-  ffi.Abi.linuxArm64: ffi.Int32(),
-  ffi.Abi.linuxIA32: ffi.Int32(),
-  ffi.Abi.linuxX64: ffi.Int32(),
-  ffi.Abi.linuxRiscv32: ffi.Int32(),
-  ffi.Abi.linuxRiscv64: ffi.Int32(),
-  ffi.Abi.macosArm64: ffi.Int64(), // <-- Only this is different.
-  ffi.Abi.macosX64: ffi.Int32(),
-  ffi.Abi.windowsArm64: ffi.Int32(),
-  ffi.Abi.windowsIA32: ffi.Int32(),
-  ffi.Abi.windowsX64: ffi.Int32(),
+/// This integer type is `Int32` on all architectures, other than macOS arm64.
+/// Where it is `Int64`.
+@AbiSpecificIntegerMapping({
+  Abi.androidArm: ffi.Int32(),
+  Abi.androidArm64: ffi.Int32(),
+  Abi.androidIA32: ffi.Int32(),
+  Abi.androidX64: ffi.Int32(),
+  Abi.androidRiscv64: ffi.Int32(),
+  Abi.fuchsiaArm64: ffi.Int32(),
+  Abi.fuchsiaX64: ffi.Int32(),
+  Abi.fuchsiaRiscv64: ffi.Int32(),
+  Abi.iosArm: ffi.Int32(),
+  Abi.iosArm64: ffi.Int32(),
+  Abi.iosX64: ffi.Int32(),
+  Abi.linuxArm: ffi.Int32(),
+  Abi.linuxArm64: ffi.Int32(),
+  Abi.linuxIA32: ffi.Int32(),
+  Abi.linuxX64: ffi.Int32(),
+  Abi.linuxRiscv32: ffi.Int32(),
+  Abi.linuxRiscv64: ffi.Int32(),
+  Abi.macosArm64: Int64(), // <-- Only this is different.
+  Abi.macosX64: ffi.Int32(),
+  Abi.windowsArm64: ffi.Int32(),
+  Abi.windowsIA32: ffi.Int32(),
+  Abi.windowsX64: ffi.Int32(),
 })
-final class $Int32 extends ffi.AbiSpecificInteger {
-  const $Int32();
+final class Int32 extends AbiSpecificInteger {
+  const Int32();
 }

pkgs/jni/lib/jni.dart

@@ -60,8 +60,6 @@
 /// This library provides classes and functions for JNI interop from Dart.
 library;
 
-export 'dart:ffi' show nullptr;
-
 export 'package:ffi/ffi.dart' show Arena, using;
 
 export 'src/errors.dart';
@@ -74,5 +72,13 @@ export 'src/lang/lang.dart';
 export 'src/nio/nio.dart';
 export 'src/third_party/generated_bindings.dart'
     hide JniBindings, JniEnv, JniEnv1, JniExceptionDetails;
-export 'src/types.dart' hide referenceType;
+export 'src/types.dart'
+    hide
+        JAccessible,
+        JArrayElementType,
+        JCallable,
+        JConstructable,
+        JObjType,
+        JType,
+        lowestCommonSuperType;
 export 'src/util/util.dart';

pkgs/jni/lib/src/accessors.dart

@@ -6,7 +6,11 @@ import 'dart:ffi';
 
 import 'package:meta/meta.dart' show internal;
 
-import '../jni.dart';
+import 'jni.dart';
+import 'jobject.dart';
+import 'jreference.dart';
+import 'third_party/generated_bindings.dart';
+import 'types.dart';
 
 void _check(JThrowablePtr exception) {
   if (exception != nullptr) {

pkgs/jni/lib/src/jarray.dart

@@ -7,20 +7,26 @@
 part of 'types.dart';
 
 final class JArrayType<E> extends JObjType<JArray<E>> {
+  @internal
   final JArrayElementType<E> elementType;
 
+  @internal
   const JArrayType(this.elementType);
 
+  @internal
   @override
   String get signature => '[${elementType.signature}';
 
+  @internal
   @override
   JArray<E> fromReference(JReference reference) =>
       JArray.fromReference(elementType, reference);
 
+  @internal
   @override
   JObjType get superType => const JObjectType();
 
+  @internal
   @override
   final int superCount = 1;
 
@@ -36,18 +42,21 @@ final class JArrayType<E> extends JObjType<JArray<E>> {
 }
 
 class JArray<E> extends JObject {
+  @internal
   final JArrayElementType<E> elementType;
 
+  @internal
   @override
-  late final JArrayType<E> $type = type(elementType) as JArrayType<E>;
+  final JArrayType<E> $type;
 
   /// The type which includes information such as the signature of this class.
-  static JObjType<JArray<T>> type<T>(JArrayElementType<T> innerType) =>
+  static JArrayType<E> type<E>(JArrayElementType<E> innerType) =>
       JArrayType(innerType);
 
   /// Construct a new [JArray] with [reference] as its underlying reference.
   JArray.fromReference(this.elementType, JReference reference)
-      : super.fromReference(reference);
+      : $type = type(elementType),
+        super.fromReference(reference);
 
   /// Creates a [JArray] of the given length from the given [elementType].
   ///

pkgs/jni/lib/src/jimplementer.dart

@@ -6,10 +6,12 @@ import 'dart:ffi';
 import 'dart:isolate';
 
 import 'package:ffi/ffi.dart';
-import 'package:meta/meta.dart';
+import 'package:meta/meta.dart' show internal;
 
-import '../_internal.dart';
+import 'accessors.dart';
+import 'jni.dart';
 import 'jobject.dart';
+import 'jreference.dart';
 import 'lang/jstring.dart';
 import 'third_party/generated_bindings.dart';
 import 'types.dart';

pkgs/jni/lib/src/jni.dart

@@ -10,9 +10,12 @@ import 'package:ffi/ffi.dart';
 import 'package:meta/meta.dart' show internal;
 import 'package:path/path.dart';
 
-import '../_internal.dart';
-import '../jni.dart';
+import 'accessors.dart';
+import 'errors.dart';
+import 'jobject.dart';
+import 'jreference.dart';
 import 'third_party/generated_bindings.dart';
+import 'types.dart';
 
 String _getLibraryFileName(String base) {
   if (Platform.isLinux || Platform.isAndroid) {

pkgs/jni/lib/src/jobject.dart

@@ -1,32 +1,37 @@
 // Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-
 import 'dart:ffi';
 
 import 'package:ffi/ffi.dart';
+import 'package:meta/meta.dart' show internal;
 
 import 'jni.dart';
 import 'jreference.dart';
 import 'lang/jstring.dart';
 import 'types.dart';
 
 final class JObjectType extends JObjType<JObject> {
+  @internal
   const JObjectType();
 
+  @internal
   @override
   String get signature => 'Ljava/lang/Object;';
 
+  @internal
   @override
   JObject fromReference(JReference reference) =>
       JObject.fromReference(reference);
 
+  @internal
   @override
   JObjType get superType => const JObjectType();
 
   // TODO(#70): Once interface implementation lands, other than [superType],
   // we should have a list of implemented interfaces.
 
+  @internal
   @override
   final int superCount = 0;
 
@@ -43,9 +48,11 @@ final class JObjectType extends JObjType<JObject> {
 ///
 /// This is the base class for classes generated by `jnigen`.
 class JObject {
+  @internal
   final JReference reference;
 
-  late final JObjType<JObject> $type = type;
+  @internal
+  final JObjType<JObject> $type = type;
 
   /// The type which includes information such as the signature of this class.
   static const JObjType<JObject> type = JObjectType();
@@ -77,7 +84,7 @@ class JObject {
   /// Casts this object to another [type].
   ///
   /// If [releaseOriginal] is `true`, the casted object will be released.
-  T castTo<T extends JObject>(
+  T as<T extends JObject>(
     JObjType<T> type, {
     bool releaseOriginal = false,
   }) {