1 /*
2 * Copyright (c) 2022, 2025, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package jdk.internal.classfile.impl;
26
27 import java.lang.classfile.*;
28 import java.lang.classfile.constantpool.Utf8Entry;
29 import java.lang.constant.MethodTypeDesc;
30 import java.lang.reflect.AccessFlag;
31 import java.util.List;
32 import java.util.Optional;
33 import java.util.function.Consumer;
34
35 public final class MethodImpl
36 extends AbstractElement
37 implements MethodModel, MethodInfo, Util.Writable {
38
39 private final ClassReader reader;
40 private final int startPos, endPos, attributesPos;
41 private List<Attribute<?>> attributes;
42 private int[] parameterSlots;
43
44 public MethodImpl(ClassReader reader, int startPos, int endPos, int attrStart) {
45 this.reader = reader;
46 this.startPos = startPos;
47 this.endPos = endPos;
48 this.attributesPos = attrStart;
49 }
50
51 @Override
52 public AccessFlags flags() {
53 return new AccessFlagsImpl(AccessFlag.Location.METHOD, reader.readU2(startPos));
54 }
55
56 @Override
57 public Optional<ClassModel> parent() {
58 if (reader instanceof ClassReaderImpl cri)
59 return Optional.of(cri.getContainedClass());
60 else
61 return Optional.empty();
62 }
63
64 @Override
65 public Utf8Entry methodName() {
66 return reader.readEntry(startPos + 2, Utf8Entry.class);
67 }
68
69 @Override
70 public Utf8Entry methodType() {
71 return reader.readEntry(startPos + 4, Utf8Entry.class);
72 }
73
74 @Override
75 public MethodTypeDesc methodTypeSymbol() {
76 return Util.methodTypeSymbol(methodType());
77 }
78
79 @Override
80 public int methodFlags() {
81 return reader.readU2(startPos);
82 }
83
84 @Override
85 public int parameterSlot(int paramNo) {
86 if (parameterSlots == null)
87 parameterSlots = Util.parseParameterSlots(methodFlags(), methodTypeSymbol());
88 return parameterSlots[paramNo];
89 }
90
91 @Override
92 public List<Attribute<?>> attributes() {
93 if (attributes == null) {
94 attributes = BoundAttribute.readAttributes(this, reader, attributesPos, reader.customAttributes());
95 }
96 return attributes;
97 }
98
99 @Override
100 public void writeTo(BufWriterImpl buf) {
101 if (Util.canSkipMethodInflation(reader, this, buf)) {
102 reader.copyBytesTo(buf, startPos, endPos - startPos);
103 }
104 else {
105 buf.writeU2U2U2(flags().flagsMask(),
106 buf.cpIndex(methodName()),
107 buf.cpIndex(methodType()));
108 Util.writeAttributes(buf, attributes());
109 }
110 }
111
112 // MethodModel
113
114 @Override
115 public Optional<CodeModel> code() {
116 return findAttribute(Attributes.code()).map(a -> (CodeModel) a);
117 }
118
119 @Override
120 public void forEach(Consumer<? super MethodElement> consumer) {
121 consumer.accept(flags());
122 for (Attribute<?> attr : attributes()) {
123 if (attr instanceof MethodElement e)
124 consumer.accept(e);
125 }
126 }
127
128 @Override
129 public void writeTo(DirectClassBuilder builder) {
130 if (builder.canWriteDirect(reader)) {
131 builder.withMethod(this);
132 }
133 else {
134 builder.withMethod(methodName(), methodType(), methodFlags(), Util.writingAll(this));
135 }
136 }
137
138 @Override
139 public String toString() {
140 return String.format("MethodModel[methodName=%s, methodType=%s, flags=%d]",
141 methodName().stringValue(), methodType().stringValue(), flags().flagsMask());
142 }
143 }