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 }