pkgs/jni/test/jobject_test.dart - native.git - Git at Google

 // 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:io';
 import 'dart:ffi';
 import 'dart:isolate';

 import 'package:test/test.dart';

 import 'package:jni/jni.dart';

 void main() {
   // Don't forget to initialize JNI.
   if (!Platform.isAndroid) {
     try {
       Jni.spawn(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
     } on JvmExistsException catch (_) {
       // TODO(#51): Support destroying and reinstantiating JVM.
     }
   }

   // The API based on JniEnv is intended to closely mimic C API of JNI,
   // And thus can be too verbose for simple experimenting and one-off uses
   // JObject API provides an easier way to perform some common operations.
   //
   // However, if binding generation using jnigen is possible, that should be
   // the first choice.
   test("Long.intValue() using JObject", () {
     // JniClass wraps a local class reference, and
     // provides convenience functions.
     final longClass = Jni.findJniClass("java/lang/Long");

     // looks for a constructor with given signature.
     // equivalently you can lookup a method with name <init>
     final longCtor = longClass.getCtorID("(J)V");

     // note that the arguments are just passed as a list.
     // allowed argument types are primitive types, JObject and its subclasses,
     // and raw JNI references (JObject). Strings will be automatically converted
     // to JNI strings.
     final long = longClass.newInstance(longCtor, [176]);

     final intValue = long.callMethodByName<int>("intValue", "()I", []);
     expect(intValue, equals(176));

     // delete any JObject and JniClass instances using .delete() after use.
     // Deletion is not strictly required since JNI objects / classes have
     // a NativeFinalizer. But deleting them after use is a good practice.
     long.delete();
     longClass.delete();
   });

   test("call a static method using JniClass APIs", () {
     final integerClass = Jni.findJniClass("java/lang/Integer");
     final result = integerClass.callStaticMethodByName<JString>(
         "toHexString", "(I)Ljava/lang/String;", [JValueInt(31)]);

     // if the object is supposed to be a Java string
     // you can call toDartString on it.
     final resultString = result.toDartString();

     // Dart string is a copy, original object can be deleted.
     result.delete();
     expect(resultString, equals("1f"));

     // Also don't forget to delete the class
     integerClass.delete();
   });

   test("Call method with null argument, expect exception", () {
     final integerClass = Jni.findJniClass("java/lang/Integer");
     expect(
         () => integerClass.callStaticMethodByName<int>(
             "parseInt", "(Ljava/lang/String;)I", [nullptr]),
         throwsException);
     integerClass.delete();
   });

   test("Try to find a non-exisiting class, expect exception", () {
     expect(() => Jni.findJniClass("java/lang/NotExists"), throwsException);
   });

   /// callMethodByName will be expensive if making same call many times
   /// Use getMethodID to get a method ID and use it in subsequent calls
   test("Example for using getMethodID", () {
     final longClass = Jni.findJniClass("java/lang/Long");
     final bitCountMethod = longClass.getStaticMethodID("bitCount", "(J)I");

     // Use newInstance if you want only one instance.
     // It finds the class, gets constructor ID and constructs an instance.
     final random = Jni.newInstance("java/util/Random", "()V", []);

     // You don't need a JniClass reference to get instance method IDs
     final nextIntMethod = random.getMethodID("nextInt", "(I)I");

     for (int i = 0; i < 100; i++) {
       int r = random.callMethod<int>(nextIntMethod, [JValueInt(256 * 256)]);
       int bits = 0;
       final jbc = longClass.callStaticMethod<int>(bitCountMethod, [r]);
       while (r != 0) {
         bits += r % 2;
         r = (r / 2).floor();
       }
       expect(jbc, equals(bits));
     }
     Jni.deleteAll([random, longClass]);
   });

   // One-off invocation of static method in single call.
   test("invoke_", () {
     final m = Jni.invokeStaticMethod<int>("java/lang/Short", "compare", "(SS)I",
         [JValueShort(1234), JValueShort(1324)]);
     expect(m, equals(1234 - 1324));
   });

   test("Java char from string", () {
     final m = Jni.invokeStaticMethod<bool>("java/lang/Character", "isLowerCase",
         "(C)Z", [JValueChar.fromString('X')]);
     expect(m, isFalse);
   });

   // One-off access of static field in single call.
   test("Get static field directly", () {
     final maxLong = Jni.retrieveStaticField<int>(
         "java/lang/Short", "MAX_VALUE", "S", JniCallType.shortType);
     expect(maxLong, equals(32767));
   });

   // Use callStringMethod if all you care about is a string result
   test("callStaticStringMethod", () {
     final longClass = Jni.findJniClass("java/lang/Long");
     const n = 1223334444;
     final strFromJava = longClass.callStaticMethodByName<String>(
         "toOctalString", "(J)Ljava/lang/String;", [n]);
     expect(strFromJava, equals(n.toRadixString(8)));
     longClass.delete();
   });

   // In JObject, JniClass, and retrieve_/invoke_ methods
   // you can also pass Dart strings, apart from range of types
   // allowed by Jni.jvalues
   // They will be converted automatically.
   test(
     "Passing strings in arguments",
     () {
       final out = Jni.retrieveStaticField<JObject>(
           "java/lang/System", "out", "Ljava/io/PrintStream;");
       // uncomment next line to see output
       // (\n because test runner prints first char at end of the line)
       //out.callMethodByName<Null>(
       //    "println", "(Ljava/lang/Object;)V", ["\nWorks (Apparently)"]);
       out.delete();
     },
   );

   test("Passing strings in arguments 2", () {
     final twelve = Jni.invokeStaticMethod<int>("java/lang/Byte", "parseByte",
         "(Ljava/lang/String;)B", ["12"], JniCallType.byteType);
     expect(twelve, equals(12));
   });

   // You can use() method on JObject for using once and deleting.
   test("use() method", () {
     final randomInt = Jni.newInstance("java/util/Random", "()V", []).use(
         (random) =>
             random.callMethodByName<int>("nextInt", "(I)I", [JValueInt(15)]));
     expect(randomInt, lessThan(15));
   });

   // The JObject and JniClass have NativeFinalizer. However, it's possible to
   // explicitly use `Arena`.
   test('Using arena', () {
     final objects = <JObject>[];
     using((arena) {
       final r = Jni.findJniClass('java/util/Random')..deletedIn(arena);
       final ctor = r.getCtorID("()V");
       for (int i = 0; i < 10; i++) {
         objects.add(r.newInstance(ctor, [])..deletedIn(arena));
       }
     });
     for (var object in objects) {
       expect(object.isDeleted, isTrue);
     }
   });

   test("enums", () {
     // Don't forget to escape $ in nested type names
     final ordinal = Jni.retrieveStaticField<JObject>(
             "java/net/Proxy\$Type", "HTTP", "Ljava/net/Proxy\$Type;")
         .use((f) => f.callMethodByName<int>("ordinal", "()I", []));
     expect(ordinal, equals(1));
   });
   test("casting", () {
     using((arena) {
       final str = "hello".toJString()..deletedIn(arena);
       final obj = str.castTo(JObject.type)..deletedIn(arena);
       final backToStr = obj.castTo(JString.type);
       expect(backToStr.toDartString(), str.toDartString());
       final _ = backToStr.castTo(JObject.type, deleteOriginal: true)
         ..deletedIn(arena);
       expect(backToStr.toDartString, throwsA(isA<UseAfterFreeException>()));
       expect(backToStr.delete, throwsA(isA<DoubleFreeException>()));
     });
   });

   test("Isolate", () {
     Isolate.spawn(doSomeWorkInIsolate, null);
   });
 }

 void doSomeWorkInIsolate(Void? _) {
   // On standalone target, make sure to call [setDylibDir] before accessing
   // any JNI function.
   //
   // otherwise getInstance will throw a "library not found" exception.
   Jni.setDylibDir(dylibDir: "build/jni_libs");
   final random = Jni.newInstance("java/util/Random", "()V", []);
   // final r = random.callMethodByName<int>("nextInt", "(I)I", [256]);
   // expect(r, lessThan(256));
   // Expect throws an [OutsideTestException]
   // but you can uncomment below print and see it works
   // print("\n$r");
   random.delete();
 }
	// 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:io';
	import 'dart:ffi';
	import 'dart:isolate';

	import 'package:test/test.dart';

	import 'package:jni/jni.dart';

	void main() {
	// Don't forget to initialize JNI.
	if (!Platform.isAndroid) {
	try {
	Jni.spawn(dylibDir: "build/jni_libs", jvmOptions: ["-Xmx128m"]);
	} on JvmExistsException catch (_) {
	// TODO(#51): Support destroying and reinstantiating JVM.
	}
	}

	// The API based on JniEnv is intended to closely mimic C API of JNI,
	// And thus can be too verbose for simple experimenting and one-off uses
	// JObject API provides an easier way to perform some common operations.
	//
	// However, if binding generation using jnigen is possible, that should be
	// the first choice.
	test("Long.intValue() using JObject", () {
	// JniClass wraps a local class reference, and
	// provides convenience functions.
	final longClass = Jni.findJniClass("java/lang/Long");

	// looks for a constructor with given signature.
	// equivalently you can lookup a method with name <init>
	final longCtor = longClass.getCtorID("(J)V");

	// note that the arguments are just passed as a list.
	// allowed argument types are primitive types, JObject and its subclasses,
	// and raw JNI references (JObject). Strings will be automatically converted
	// to JNI strings.
	final long = longClass.newInstance(longCtor, [176]);

	final intValue = long.callMethodByName<int>("intValue", "()I", []);
	expect(intValue, equals(176));

	// delete any JObject and JniClass instances using .delete() after use.
	// Deletion is not strictly required since JNI objects / classes have
	// a NativeFinalizer. But deleting them after use is a good practice.
	long.delete();
	longClass.delete();
	});

	test("call a static method using JniClass APIs", () {
	final integerClass = Jni.findJniClass("java/lang/Integer");
	final result = integerClass.callStaticMethodByName<JString>(
	"toHexString", "(I)Ljava/lang/String;", [JValueInt(31)]);

	// if the object is supposed to be a Java string
	// you can call toDartString on it.
	final resultString = result.toDartString();

	// Dart string is a copy, original object can be deleted.
	result.delete();
	expect(resultString, equals("1f"));

	// Also don't forget to delete the class
	integerClass.delete();
	});

	test("Call method with null argument, expect exception", () {
	final integerClass = Jni.findJniClass("java/lang/Integer");
	expect(
	() => integerClass.callStaticMethodByName<int>(
	"parseInt", "(Ljava/lang/String;)I", [nullptr]),
	throwsException);
	integerClass.delete();
	});

	test("Try to find a non-exisiting class, expect exception", () {
	expect(() => Jni.findJniClass("java/lang/NotExists"), throwsException);
	});

	/// callMethodByName will be expensive if making same call many times
	/// Use getMethodID to get a method ID and use it in subsequent calls
	test("Example for using getMethodID", () {
	final longClass = Jni.findJniClass("java/lang/Long");
	final bitCountMethod = longClass.getStaticMethodID("bitCount", "(J)I");

	// Use newInstance if you want only one instance.
	// It finds the class, gets constructor ID and constructs an instance.
	final random = Jni.newInstance("java/util/Random", "()V", []);

	// You don't need a JniClass reference to get instance method IDs
	final nextIntMethod = random.getMethodID("nextInt", "(I)I");

	for (int i = 0; i < 100; i++) {
	int r = random.callMethod<int>(nextIntMethod, [JValueInt(256 * 256)]);
	int bits = 0;
	final jbc = longClass.callStaticMethod<int>(bitCountMethod, [r]);
	while (r != 0) {
	bits += r % 2;
	r = (r / 2).floor();
	}
	expect(jbc, equals(bits));
	}
	Jni.deleteAll([random, longClass]);
	});

	// One-off invocation of static method in single call.
	test("invoke_", () {
	final m = Jni.invokeStaticMethod<int>("java/lang/Short", "compare", "(SS)I",
	[JValueShort(1234), JValueShort(1324)]);
	expect(m, equals(1234 - 1324));
	});

	test("Java char from string", () {
	final m = Jni.invokeStaticMethod<bool>("java/lang/Character", "isLowerCase",
	"(C)Z", [JValueChar.fromString('X')]);
	expect(m, isFalse);
	});

	// One-off access of static field in single call.
	test("Get static field directly", () {
	final maxLong = Jni.retrieveStaticField<int>(
	"java/lang/Short", "MAX_VALUE", "S", JniCallType.shortType);
	expect(maxLong, equals(32767));
	});

	// Use callStringMethod if all you care about is a string result
	test("callStaticStringMethod", () {
	final longClass = Jni.findJniClass("java/lang/Long");
	const n = 1223334444;
	final strFromJava = longClass.callStaticMethodByName<String>(
	"toOctalString", "(J)Ljava/lang/String;", [n]);
	expect(strFromJava, equals(n.toRadixString(8)));
	longClass.delete();
	});

	// In JObject, JniClass, and retrieve_/invoke_ methods
	// you can also pass Dart strings, apart from range of types
	// allowed by Jni.jvalues
	// They will be converted automatically.
	test(
	"Passing strings in arguments",
	() {
	final out = Jni.retrieveStaticField<JObject>(
	"java/lang/System", "out", "Ljava/io/PrintStream;");
	// uncomment next line to see output
	// (\n because test runner prints first char at end of the line)
	//out.callMethodByName<Null>(
	// "println", "(Ljava/lang/Object;)V", ["\nWorks (Apparently)"]);
	out.delete();
	},
	);

	test("Passing strings in arguments 2", () {
	final twelve = Jni.invokeStaticMethod<int>("java/lang/Byte", "parseByte",
	"(Ljava/lang/String;)B", ["12"], JniCallType.byteType);
	expect(twelve, equals(12));
	});

	// You can use() method on JObject for using once and deleting.
	test("use() method", () {
	final randomInt = Jni.newInstance("java/util/Random", "()V", []).use(
	(random) =>
	random.callMethodByName<int>("nextInt", "(I)I", [JValueInt(15)]));
	expect(randomInt, lessThan(15));
	});

	// The JObject and JniClass have NativeFinalizer. However, it's possible to
	// explicitly use `Arena`.
	test('Using arena', () {
	final objects = <JObject>[];
	using((arena) {
	final r = Jni.findJniClass('java/util/Random')..deletedIn(arena);
	final ctor = r.getCtorID("()V");
	for (int i = 0; i < 10; i++) {
	objects.add(r.newInstance(ctor, [])..deletedIn(arena));
	}
	});
	for (var object in objects) {
	expect(object.isDeleted, isTrue);
	}
	});

	test("enums", () {
	// Don't forget to escape $ in nested type names
	final ordinal = Jni.retrieveStaticField<JObject>(
	"java/net/Proxy\$Type", "HTTP", "Ljava/net/Proxy\$Type;")
	.use((f) => f.callMethodByName<int>("ordinal", "()I", []));
	expect(ordinal, equals(1));
	});
	test("casting", () {
	using((arena) {
	final str = "hello".toJString()..deletedIn(arena);
	final obj = str.castTo(JObject.type)..deletedIn(arena);
	final backToStr = obj.castTo(JString.type);
	expect(backToStr.toDartString(), str.toDartString());
	final _ = backToStr.castTo(JObject.type, deleteOriginal: true)
	..deletedIn(arena);
	expect(backToStr.toDartString, throwsA(isA<UseAfterFreeException>()));
	expect(backToStr.delete, throwsA(isA<DoubleFreeException>()));
	});
	});

	test("Isolate", () {
	Isolate.spawn(doSomeWorkInIsolate, null);
	});
	}

	void doSomeWorkInIsolate(Void? _) {
	// On standalone target, make sure to call [setDylibDir] before accessing
	// any JNI function.
	//
	// otherwise getInstance will throw a "library not found" exception.
	Jni.setDylibDir(dylibDir: "build/jni_libs");
	final random = Jni.newInstance("java/util/Random", "()V", []);
	// final r = random.callMethodByName<int>("nextInt", "(I)I", [256]);
	// expect(r, lessThan(256));
	// Expect throws an [OutsideTestException]
	// but you can uncomment below print and see it works
	// print("\n$r");
	random.delete();
	}