1 /*
 2  * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 /*
25  * @test
26  * @run testng TestNestedCapturingLambda
27  */
28 
29 import org.testng.Assert;
30 import org.testng.annotations.Test;
31 
32 import java.lang.invoke.MethodHandle;
33 import java.lang.invoke.MethodHandles;
34 import java.lang.reflect.Method;
35 import java.lang.reflect.code.OpTransformer;
36 import java.lang.reflect.code.Quotable;
37 import java.lang.reflect.code.bytecode.BytecodeGenerator;
38 import java.lang.reflect.code.op.CoreOp;
39 import java.lang.runtime.CodeReflection;
40 import java.util.Optional;
41 import java.util.function.IntSupplier;
42 import java.util.stream.Stream;
43 
44 public class TestNestedCapturingLambda {
45 
46     @FunctionalInterface
47     interface QIntSupplier extends IntSupplier, Quotable {
48     }
49 
50     @CodeReflection
51     static public int f(int a) {
52         if (a > 0) {
53             QIntSupplier s = () -> a;
54             test(s, a);
55             return s.getAsInt();
56         } else {
57             return 0;
58         }
59     }
60 
61     static void test(QIntSupplier s, int a) {
62         @SuppressWarnings("unchecked")
63         CoreOp.Var<Integer> capture = (CoreOp.Var<Integer>) s.quoted().capturedValues().values().iterator().next();
64         Assert.assertEquals(capture.value().intValue(), a);
65     }
66 
67     @Test
68     public void testf() throws Throwable {
69         CoreOp.FuncOp f = getFuncOp("f");
70 
71         MethodHandle mh = generate(f);
72 
73         Assert.assertEquals((int) mh.invoke(42), f(42));
74         Assert.assertEquals((int) mh.invoke(-1), f(-1));
75     }
76 
77     static MethodHandle generate(CoreOp.FuncOp f) {
78         f.writeTo(System.out);
79 
80         CoreOp.FuncOp lf = f.transform(OpTransformer.LOWERING_TRANSFORMER);
81         lf.writeTo(System.out);
82 
83         return BytecodeGenerator.generate(MethodHandles.lookup(), lf);
84     }
85 
86     static CoreOp.FuncOp getFuncOp(String name) {
87         Optional<Method> om = Stream.of(TestNestedCapturingLambda.class.getDeclaredMethods())
88                 .filter(m -> m.getName().equals(name))
89                 .findFirst();
90 
91         Method m = om.get();
92         return m.getCodeModel().get();
93     }
94 }