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 
  26 package jdk.internal.classfile.impl;
  27 
  28 import java.lang.classfile.*;
  29 import java.lang.classfile.attribute.*;
  30 import java.lang.classfile.constantpool.*;
  31 import java.util.ArrayList;
  32 import java.util.Collections;
  33 import java.util.List;
  34 import java.util.Objects;
  35 import java.util.Optional;
  36 import java.util.function.Function;
  37 
  38 import jdk.internal.access.SharedSecrets;
  39 
  40 import static java.lang.classfile.Attributes.*;
  41 
  42 public abstract sealed class BoundAttribute<T extends Attribute<T>>
  43         extends AbstractElement
  44         implements Attribute<T>, Util.Writable {
  45 
  46     static final int NAME_AND_LENGTH_PREFIX = 6;
  47     private final AttributeMapper<T> mapper;
  48     final ClassReaderImpl classReader;
  49     final int payloadStart;
  50     Utf8Entry name;
  51 
  52     BoundAttribute(ClassReader classReader, AttributeMapper<T> mapper, int payloadStart) {
  53         this.mapper = mapper;
  54         this.classReader = (ClassReaderImpl)classReader;
  55         this.payloadStart = payloadStart;
  56     }
  57 
  58     public int payloadLen() {
  59         return classReader.readInt(payloadStart - 4);
  60     }
  61 
  62     @Override
  63     public Utf8Entry attributeName() {
  64         if (name == null) {
  65             name = classReader.readEntry(payloadStart - 6, Utf8Entry.class);
  66         }
  67         return name;
  68     }
  69 
  70     @Override
  71     public AttributeMapper<T> attributeMapper() {
  72         return mapper;
  73     }
  74 
  75     public byte[] contents() {
  76         return classReader.readBytes(payloadStart, payloadLen());
  77     }
  78 
  79     @Override
  80     public void writeTo(DirectClassBuilder builder) {
  81         builder.writeAttribute(this);
  82     }
  83 
  84     @Override
  85     public void writeTo(DirectCodeBuilder builder) {
  86         builder.writeAttribute(this);
  87     }
  88 
  89     @Override
  90     public void writeTo(DirectMethodBuilder builder) {
  91         builder.writeAttribute(this);
  92     }
  93 
  94     @Override
  95     public void writeTo(DirectFieldBuilder builder) {
  96         builder.writeAttribute(this);
  97     }
  98 
  99     @Override
 100     @SuppressWarnings("unchecked")
 101     public void writeTo(BufWriterImpl buf) {
 102         if (!buf.canWriteDirect(classReader))
 103             attributeMapper().writeAttribute(buf, (T) this);
 104         else
 105             classReader.copyBytesTo(buf, payloadStart - NAME_AND_LENGTH_PREFIX, payloadLen() + NAME_AND_LENGTH_PREFIX);
 106     }
 107 
 108     public ConstantPool constantPool() {
 109         return classReader;
 110     }
 111 
 112     @Override
 113     public String toString() {
 114         return String.format("Attribute[name=%s]", mapper.name());
 115     }
 116 
 117     <E extends PoolEntry> List<E> readEntryList(int p, Class<E> type) {
 118         int cnt = classReader.readU2(p);
 119         p += 2;
 120         var entries = new Object[cnt];
 121         int end = p + (cnt * 2);
 122         for (int i = 0; p < end; i++, p += 2) {
 123             entries[i] = classReader.readEntry(p, type);
 124         }
 125         return SharedSecrets.getJavaUtilCollectionAccess().listFromTrustedArray(entries);
 126     }
 127 
 128     public static List<Attribute<?>> readAttributes(AttributedElement enclosing, ClassReader reader, int pos,
 129                                                                   Function<Utf8Entry, AttributeMapper<?>> customAttributes) {
 130         int size = reader.readU2(pos);
 131         var filled = new ArrayList<Attribute<?>>(size);
 132         int p = pos + 2;
 133         int cfLen = reader.classfileLength();
 134         for (int i = 0; i < size; ++i) {
 135             Utf8Entry name = reader.readEntry(p, Utf8Entry.class);
 136             int len = reader.readInt(p + 2);
 137             p += 6;
 138             if (len < 0 || len > cfLen - p) {
 139                 throw new IllegalArgumentException("attribute " + name.stringValue() + " too big to handle");
 140             }
 141 
 142             var mapper = standardAttribute(name);
 143             if (mapper == null) {
 144                 mapper = customAttributes.apply(name);
 145             }
 146             if (mapper != null) {
 147                 filled.add(Objects.requireNonNull(mapper.readAttribute(enclosing, reader, p)));
 148             } else {
 149                 AttributeMapper<UnknownAttribute> fakeMapper = new AttributeMapper<>() {
 150                     @Override
 151                     public String name() {
 152                         return name.stringValue();
 153                     }
 154 
 155                     @Override
 156                     public UnknownAttribute readAttribute(AttributedElement enclosing, ClassReader cf, int pos) {
 157                         // Will never get called
 158                         throw new UnsupportedOperationException();
 159                     }
 160 
 161                     @Override
 162                     public void writeAttribute(BufWriter buf, UnknownAttribute attr) {
 163                         buf.writeIndex(name);
 164                         var cont = attr.contents();
 165                         buf.writeInt(cont.length);
 166                         buf.writeBytes(cont);
 167                     }
 168 
 169                     @Override
 170                     public boolean allowMultiple() {
 171                         return true;
 172                     }
 173 
 174                     @Override
 175                     public AttributeMapper.AttributeStability stability() {
 176                         return AttributeStability.UNKNOWN;
 177                     }
 178                 };
 179                 filled.add(new BoundUnknownAttribute(reader, fakeMapper, p));
 180             }
 181             p += len;
 182         }
 183         return Collections.unmodifiableList(filled);
 184     }
 185 
 186     public static final class BoundUnknownAttribute extends BoundAttribute<UnknownAttribute>
 187             implements UnknownAttribute {
 188         public BoundUnknownAttribute(ClassReader cf, AttributeMapper<UnknownAttribute> mapper, int pos) {
 189             super(cf, mapper, pos);
 190         }
 191     }
 192 
 193     public static final class BoundStackMapTableAttribute
 194             extends BoundAttribute<StackMapTableAttribute>
 195             implements StackMapTableAttribute {
 196         final MethodModel method;
 197         final LabelContext ctx;
 198         List<StackMapFrameInfo> entries = null;
 199 
 200         public BoundStackMapTableAttribute(CodeImpl code, ClassReader cf, AttributeMapper<StackMapTableAttribute> mapper, int pos) {
 201             super(cf, mapper, pos);
 202             method = code.parent().orElseThrow();
 203             ctx = code;
 204         }
 205 
 206         @Override
 207         public List<StackMapFrameInfo> entries() {
 208             if (entries == null) {
 209                 entries = new StackMapDecoder(classReader, payloadStart, ctx, StackMapDecoder.initFrameLocals(method)).entries();
 210             }
 211             return entries;
 212         }
 213 
 214         @Override
 215         public void writeTo(BufWriterImpl buf) {
 216             if (buf.canWriteDirect(classReader) && buf.labelsMatch(ctx)) {
 217                 classReader.copyBytesTo(buf, payloadStart - NAME_AND_LENGTH_PREFIX, payloadLen() + NAME_AND_LENGTH_PREFIX);
 218             } else {
 219                 attributeMapper().writeAttribute(buf, this);
 220             }
 221         }
 222     }
 223 
 224     public static final class BoundSyntheticAttribute extends BoundAttribute<SyntheticAttribute>
 225             implements SyntheticAttribute {
 226         public BoundSyntheticAttribute(ClassReader cf, AttributeMapper<SyntheticAttribute> mapper, int pos) {
 227             super(cf, mapper, pos);
 228         }
 229     }
 230 
 231     public static final class BoundLineNumberTableAttribute
 232             extends BoundAttribute<LineNumberTableAttribute>
 233             implements LineNumberTableAttribute {
 234         private List<LineNumberInfo> lineNumbers = null;
 235 
 236         public BoundLineNumberTableAttribute(ClassReader cf, AttributeMapper<LineNumberTableAttribute> mapper, int pos) {
 237             super(cf, mapper, pos);
 238         }
 239 
 240         @Override
 241         public List<LineNumberInfo> lineNumbers() {
 242             if (lineNumbers == null) {
 243                 int nLn = classReader.readU2(payloadStart);
 244                 LineNumberInfo[] elements = new LineNumberInfo[nLn];
 245                 int p = payloadStart + 2;
 246                 int pEnd = p + (nLn * 4);
 247                 for (int i = 0; p < pEnd; p += 4, i++) {
 248                     int startPc = classReader.readU2(p);
 249                     int lineNumber = classReader.readU2(p + 2);
 250                     elements[i] = LineNumberInfo.of(startPc, lineNumber);
 251                 }
 252                 lineNumbers = List.of(elements);
 253             }
 254             return lineNumbers;
 255         }
 256     }
 257 
 258     public static final class BoundCharacterRangeTableAttribute extends BoundAttribute<CharacterRangeTableAttribute> implements CharacterRangeTableAttribute {
 259         private List<CharacterRangeInfo> characterRangeTable = null;
 260 
 261         public BoundCharacterRangeTableAttribute(ClassReader cf, AttributeMapper<CharacterRangeTableAttribute> mapper, int pos) {
 262             super(cf, mapper, pos);
 263         }
 264 
 265         @Override
 266         public List<CharacterRangeInfo> characterRangeTable() {
 267             if (characterRangeTable == null) {
 268                 int nLn = classReader.readU2(payloadStart);
 269                 CharacterRangeInfo[] elements = new CharacterRangeInfo[nLn];
 270                 int p = payloadStart + 2;
 271                 int pEnd = p + (nLn * 14);
 272                 for (int i = 0; p < pEnd; p += 14, i++) {
 273                     int startPc = classReader.readU2(p);
 274                     int endPc = classReader.readU2(p + 2);
 275                     int characterRangeStart = classReader.readInt(p + 4);
 276                     int characterRangeEnd = classReader.readInt(p + 8);
 277                     int flags = classReader.readU2(p + 12);
 278                     elements[i] = CharacterRangeInfo.of(startPc, endPc, characterRangeStart, characterRangeEnd, flags);
 279                 }
 280                 characterRangeTable = List.of(elements);
 281             }
 282             return characterRangeTable;
 283         }
 284     }
 285 
 286     public static final class BoundLocalVariableTableAttribute
 287             extends BoundAttribute<LocalVariableTableAttribute>
 288             implements LocalVariableTableAttribute {
 289         private final CodeImpl codeAttribute;
 290         private List<LocalVariableInfo> localVars = null;
 291 
 292         public BoundLocalVariableTableAttribute(AttributedElement enclosing, ClassReader cf, AttributeMapper<LocalVariableTableAttribute> mapper, int pos) {
 293             super(cf, mapper, pos);
 294             if (enclosing instanceof CodeImpl ci) {
 295                 this.codeAttribute = ci;
 296             } else {
 297                 throw new IllegalArgumentException("Invalid LocalVariableTable attribute location");
 298             }
 299         }
 300 
 301         @Override
 302         public List<LocalVariableInfo> localVariables() {
 303             if (localVars == null) {
 304                 int cnt = classReader.readU2(payloadStart);
 305                 BoundLocalVariable[] elements = new BoundLocalVariable[cnt];
 306                 int p = payloadStart + 2;
 307                 int pEnd = p + (cnt * 10);
 308                 for (int i = 0; p < pEnd; p += 10, i++) {
 309                     elements[i] = new BoundLocalVariable(codeAttribute, p);
 310                 }
 311                 localVars = List.of(elements);
 312             }
 313             return localVars;
 314         }
 315     }
 316 
 317     public static final class BoundLocalVariableTypeTableAttribute
 318             extends BoundAttribute<LocalVariableTypeTableAttribute>
 319             implements LocalVariableTypeTableAttribute {
 320         private final CodeImpl codeAttribute;
 321         private List<LocalVariableTypeInfo> localVars = null;
 322 
 323         public BoundLocalVariableTypeTableAttribute(AttributedElement enclosing, ClassReader cf, AttributeMapper<LocalVariableTypeTableAttribute> mapper, int pos) {
 324             super(cf, mapper, pos);
 325             if (enclosing instanceof CodeImpl ci) {
 326                 this.codeAttribute = ci;
 327             } else {
 328                 throw new IllegalArgumentException("Invalid LocalVariableTypeTable attribute location");
 329             }
 330         }
 331 
 332         @Override
 333         public List<LocalVariableTypeInfo> localVariableTypes() {
 334             if (localVars == null) {
 335                 final int cnt = classReader.readU2(payloadStart);
 336                 BoundLocalVariableType[] elements = new BoundLocalVariableType[cnt];
 337                 int p = payloadStart + 2;
 338                 int pEnd = p + (cnt * 10);
 339                 for (int i = 0; p < pEnd; p += 10, i++) {
 340                     elements[i] = new BoundLocalVariableType(codeAttribute, p);
 341                 }
 342                 localVars = List.of(elements);
 343             }
 344             return localVars;
 345         }
 346     }
 347 
 348     public static final class BoundMethodParametersAttribute extends BoundAttribute<MethodParametersAttribute>
 349             implements MethodParametersAttribute {
 350         private List<MethodParameterInfo> parameters = null;
 351 
 352         public BoundMethodParametersAttribute(ClassReader cf, AttributeMapper<MethodParametersAttribute> mapper, int pos) {
 353             super(cf, mapper, pos);
 354         }
 355 
 356         @Override
 357         public List<MethodParameterInfo> parameters() {
 358             if (parameters == null) {
 359                 final int cnt = classReader.readU1(payloadStart);
 360                 MethodParameterInfo[] elements = new MethodParameterInfo[cnt];
 361                 int p = payloadStart + 1;
 362                 int pEnd = p + (cnt * 4);
 363                 for (int i = 0; p < pEnd; p += 4, i++) {
 364                     Utf8Entry name = classReader.readEntryOrNull(p, Utf8Entry.class);
 365                     int accessFlags = classReader.readU2(p + 2);
 366                     elements[i] = MethodParameterInfo.of(Optional.ofNullable(name), accessFlags);
 367                 }
 368                 parameters = List.of(elements);
 369             }
 370             return parameters;
 371         }
 372     }
 373 
 374     public static final class BoundModuleHashesAttribute extends BoundAttribute<ModuleHashesAttribute>
 375             implements ModuleHashesAttribute {
 376         private List<ModuleHashInfo> hashes = null;
 377 
 378         public BoundModuleHashesAttribute(ClassReader cf, AttributeMapper<ModuleHashesAttribute> mapper, int pos) {
 379             super(cf, mapper, pos);
 380         }
 381 
 382         @Override
 383         public Utf8Entry algorithm() {
 384             return classReader.readEntry(payloadStart, Utf8Entry.class);
 385         }
 386 
 387         @Override
 388         public List<ModuleHashInfo> hashes() {
 389             if (hashes == null) {
 390                 final int cnt = classReader.readU2(payloadStart + 2);
 391                 ModuleHashInfo[] elements = new ModuleHashInfo[cnt];
 392                 int p = payloadStart + 4;
 393                 //System.err.printf("%5d: ModuleHashesAttr alg = %s, cnt = %d%n", pos, algorithm(), cnt);
 394                 for (int i = 0; i < cnt; ++i) {
 395                     ModuleEntry module = classReader.readEntry(p, ModuleEntry.class);
 396                     int hashLength = classReader.readU2(p + 2);
 397                     //System.err.printf("%5d:     [%d] module = %s, hashLength = %d%n", p, i, module, hashLength);
 398                     p += 4;
 399                     elements[i] = ModuleHashInfo.of(module, classReader.readBytes(p, hashLength));
 400                     p += hashLength;
 401                 }
 402                 hashes = List.of(elements);
 403             }
 404             return hashes;
 405         }
 406     }
 407 
 408     public static final class BoundRecordAttribute extends BoundAttribute<RecordAttribute>
 409             implements RecordAttribute {
 410         private List<RecordComponentInfo> components = null;
 411 
 412         public BoundRecordAttribute(ClassReader cf, AttributeMapper<RecordAttribute> mapper, int pos) {
 413             super(cf, mapper, pos);
 414         }
 415 
 416         @Override
 417         public List<RecordComponentInfo> components() {
 418             if (components == null) {
 419                 final int cnt = classReader.readU2(payloadStart);
 420                 RecordComponentInfo[] elements = new RecordComponentInfo[cnt];
 421                 int p = payloadStart + 2;
 422                 for (int i = 0; i < cnt; i++) {
 423                     elements[i] = new BoundRecordComponentInfo(classReader, p);
 424                     p = classReader.skipAttributeHolder(p + 4);
 425                 }
 426                 components = List.of(elements);
 427             }
 428             return components;
 429         }
 430     }
 431 
 432     public static final class BoundDeprecatedAttribute extends BoundAttribute<DeprecatedAttribute>
 433             implements DeprecatedAttribute {
 434         public BoundDeprecatedAttribute(ClassReader cf, AttributeMapper<DeprecatedAttribute> mapper, int pos) {
 435             super(cf, mapper, pos);
 436         }
 437     }
 438 
 439     public static final class BoundSignatureAttribute extends BoundAttribute<SignatureAttribute>
 440             implements SignatureAttribute {
 441         public BoundSignatureAttribute(ClassReader cf, AttributeMapper<SignatureAttribute> mapper, int pos) {
 442             super(cf, mapper, pos);
 443         }
 444 
 445         @Override
 446         public Utf8Entry signature() {
 447             return classReader.readEntry(payloadStart, Utf8Entry.class);
 448         }
 449     }
 450 
 451     public static final class BoundSourceFileAttribute extends BoundAttribute<SourceFileAttribute>
 452             implements SourceFileAttribute {
 453         public BoundSourceFileAttribute(ClassReader cf, AttributeMapper<SourceFileAttribute> mapper, int pos) {
 454             super(cf, mapper, pos);
 455         }
 456 
 457         @Override
 458         public Utf8Entry sourceFile() {
 459             return classReader.readEntry(payloadStart, Utf8Entry.class);
 460         }
 461 
 462     }
 463 
 464     public static final class BoundModuleMainClassAttribute extends BoundAttribute<ModuleMainClassAttribute> implements ModuleMainClassAttribute {
 465         public BoundModuleMainClassAttribute(ClassReader cf, AttributeMapper<ModuleMainClassAttribute> mapper, int pos) {
 466             super(cf, mapper, pos);
 467         }
 468 
 469         @Override
 470         public ClassEntry mainClass() {
 471             return classReader.readEntry(payloadStart, ClassEntry.class);
 472         }
 473     }
 474 
 475     public static final class BoundNestHostAttribute extends BoundAttribute<NestHostAttribute>
 476             implements NestHostAttribute {
 477         public BoundNestHostAttribute(ClassReader cf, AttributeMapper<NestHostAttribute> mapper, int pos) {
 478             super(cf, mapper, pos);
 479         }
 480 
 481         @Override
 482         public ClassEntry nestHost() {
 483             return classReader.readEntry(payloadStart, ClassEntry.class);
 484         }
 485     }
 486 
 487     public static final class BoundSourceDebugExtensionAttribute extends BoundAttribute<SourceDebugExtensionAttribute>
 488             implements SourceDebugExtensionAttribute {
 489         public BoundSourceDebugExtensionAttribute(ClassReader cf, AttributeMapper<SourceDebugExtensionAttribute> mapper, int pos) {
 490             super(cf, mapper, pos);
 491         }
 492     }
 493 
 494     public static final class BoundConstantValueAttribute extends BoundAttribute<ConstantValueAttribute>
 495             implements ConstantValueAttribute {
 496         public BoundConstantValueAttribute(ClassReader cf, AttributeMapper<ConstantValueAttribute> mapper, int pos) {
 497             super(cf, mapper, pos);
 498         }
 499 
 500         @Override
 501         public ConstantValueEntry constant() {
 502             return classReader.readEntry(payloadStart, ConstantValueEntry.class);
 503         }
 504 
 505     }
 506 
 507     public static final class BoundModuleTargetAttribute extends BoundAttribute<ModuleTargetAttribute>
 508             implements ModuleTargetAttribute {
 509         public BoundModuleTargetAttribute(ClassReader cf, AttributeMapper<ModuleTargetAttribute> mapper, int pos) {
 510             super(cf, mapper, pos);
 511         }
 512 
 513         @Override
 514         public Utf8Entry targetPlatform() {
 515             return classReader.readEntry(payloadStart, Utf8Entry.class);
 516         }
 517     }
 518 
 519     public static final class BoundCompilationIDAttribute extends BoundAttribute<CompilationIDAttribute>
 520             implements CompilationIDAttribute {
 521         public BoundCompilationIDAttribute(ClassReader cf, AttributeMapper<CompilationIDAttribute> mapper, int pos) {
 522             super(cf, mapper, pos);
 523         }
 524 
 525         @Override
 526         public Utf8Entry compilationId() {
 527             return classReader.readEntry(payloadStart, Utf8Entry.class);
 528         }
 529     }
 530 
 531     public static final class BoundSourceIDAttribute extends BoundAttribute<SourceIDAttribute>
 532             implements SourceIDAttribute {
 533         public BoundSourceIDAttribute(ClassReader cf, AttributeMapper<SourceIDAttribute> mapper, int pos) {
 534             super(cf, mapper, pos);
 535         }
 536 
 537         @Override
 538         public Utf8Entry sourceId() {
 539             return classReader.readEntry(payloadStart, Utf8Entry.class);
 540         }
 541     }
 542 
 543     public static final class BoundModuleResolutionAttribute extends BoundAttribute<ModuleResolutionAttribute>
 544             implements ModuleResolutionAttribute {
 545         public BoundModuleResolutionAttribute(ClassReader cf, AttributeMapper<ModuleResolutionAttribute> mapper, int pos) {
 546             super(cf, mapper, pos);
 547         }
 548 
 549         @Override
 550         public int resolutionFlags() {
 551             return classReader.readU2(payloadStart);
 552         }
 553     }
 554 
 555     public static final class BoundExceptionsAttribute extends BoundAttribute<ExceptionsAttribute>
 556             implements ExceptionsAttribute {
 557         private List<ClassEntry> exceptions = null;
 558 
 559         public BoundExceptionsAttribute(ClassReader cf, AttributeMapper<ExceptionsAttribute> mapper, int pos) {
 560             super(cf, mapper, pos);
 561         }
 562 
 563         @Override
 564         public List<ClassEntry> exceptions() {
 565             if (exceptions == null) {
 566                 exceptions = readEntryList(payloadStart, ClassEntry.class);
 567             }
 568             return exceptions;
 569         }
 570     }
 571 
 572     public static final class BoundModuleAttribute extends BoundAttribute<ModuleAttribute>
 573             implements ModuleAttribute {
 574         private List<ModuleRequireInfo> requires = null;
 575         private List<ModuleExportInfo> exports = null;
 576         private List<ModuleOpenInfo> opens = null;
 577         private List<ClassEntry> uses = null;
 578         private List<ModuleProvideInfo> provides = null;
 579 
 580         public BoundModuleAttribute(ClassReader cf, AttributeMapper<ModuleAttribute> mapper, int pos) {
 581             super(cf, mapper, pos);
 582         }
 583 
 584         @Override
 585         public ModuleEntry moduleName() {
 586             return classReader.readEntry(payloadStart, ModuleEntry.class);
 587         }
 588 
 589         @Override
 590         public int moduleFlagsMask() {
 591             return classReader.readU2(payloadStart + 2);
 592         }
 593 
 594         @Override
 595         public Optional<Utf8Entry> moduleVersion() {
 596             return Optional.ofNullable(classReader.readEntryOrNull(payloadStart + 4, Utf8Entry.class));
 597         }
 598 
 599         @Override
 600         public List<ModuleRequireInfo> requires() {
 601             if (requires == null) {
 602                 structure();
 603             }
 604             return requires;
 605         }
 606 
 607         @Override
 608         public List<ModuleExportInfo> exports() {
 609             if (exports == null) {
 610                 structure();
 611             }
 612             return exports;
 613         }
 614 
 615         @Override
 616         public List<ModuleOpenInfo> opens() {
 617             if (opens == null) {
 618                 structure();
 619             }
 620             return opens;
 621         }
 622 
 623         @Override
 624         public List<ClassEntry> uses() {
 625             if (uses == null) {
 626                 structure();
 627             }
 628             return uses;
 629         }
 630 
 631         @Override
 632         public List<ModuleProvideInfo> provides() {
 633             if (provides == null) {
 634                 structure();
 635             }
 636             return provides;
 637         }
 638 
 639         private void structure() {
 640             int p = payloadStart + 8;
 641 
 642             {
 643                 int cnt = classReader.readU2(payloadStart + 6);
 644                 ModuleRequireInfo[] elements = new ModuleRequireInfo[cnt];
 645                 int end = p + (cnt * 6);
 646                 for (int i = 0; p < end; p += 6, i++) {
 647                     elements[i] = ModuleRequireInfo.of(classReader.readEntry(p, ModuleEntry.class),
 648                             classReader.readU2(p + 2),
 649                             classReader.readEntryOrNull(p + 4, Utf8Entry.class));
 650                 }
 651                 requires = List.of(elements);
 652             }
 653 
 654             {
 655                 int cnt = classReader.readU2(p);
 656                 p += 2;
 657                 ModuleExportInfo[] elements = new ModuleExportInfo[cnt];
 658                 for (int i = 0; i < cnt; i++) {
 659                     PackageEntry pe = classReader.readEntry(p, PackageEntry.class);
 660                     int exportFlags = classReader.readU2(p + 2);
 661                     p += 4;
 662                     List<ModuleEntry> exportsTo = readEntryList(p, ModuleEntry.class);
 663                     p += 2 + exportsTo.size() * 2;
 664                     elements[i] = ModuleExportInfo.of(pe, exportFlags, exportsTo);
 665                 }
 666                 exports = List.of(elements);
 667             }
 668 
 669             {
 670                 int cnt = classReader.readU2(p);
 671                 p += 2;
 672                 ModuleOpenInfo[] elements = new ModuleOpenInfo[cnt];
 673                 for (int i = 0; i < cnt; i++) {
 674                     PackageEntry po = classReader.readEntry(p, PackageEntry.class);
 675                     int opensFlags = classReader.readU2(p + 2);
 676                     p += 4;
 677                     List<ModuleEntry> opensTo = readEntryList(p, ModuleEntry.class);
 678                     p += 2 + opensTo.size() * 2;
 679                     elements[i] = ModuleOpenInfo.of(po, opensFlags, opensTo);
 680                 }
 681                 opens = List.of(elements);
 682             }
 683 
 684             {
 685                 uses = readEntryList(p, ClassEntry.class);
 686                 p += 2 + uses.size() * 2;
 687                 int cnt = classReader.readU2(p);
 688                 p += 2;
 689                 ModuleProvideInfo[] elements = new ModuleProvideInfo[cnt];
 690                 provides = new ArrayList<>(cnt);
 691                 for (int i = 0; i < cnt; i++) {
 692                     ClassEntry c = classReader.readEntry(p, ClassEntry.class);
 693                     p += 2;
 694                     List<ClassEntry> providesWith = readEntryList(p, ClassEntry.class);
 695                     p += 2 + providesWith.size() * 2;
 696                     elements[i] = ModuleProvideInfo.of(c, providesWith);
 697                 }
 698                 provides = List.of(elements);
 699             }
 700         }
 701     }
 702 
 703     public static final class BoundModulePackagesAttribute extends BoundAttribute<ModulePackagesAttribute>
 704             implements ModulePackagesAttribute {
 705         private List<PackageEntry> packages = null;
 706 
 707         public BoundModulePackagesAttribute(ClassReader cf, AttributeMapper<ModulePackagesAttribute> mapper, int pos) {
 708             super(cf, mapper, pos);
 709         }
 710 
 711         @Override
 712         public List<PackageEntry> packages() {
 713             if (packages == null) {
 714                 packages = readEntryList(payloadStart, PackageEntry.class);
 715             }
 716             return packages;
 717         }
 718     }
 719 
 720     public static final class BoundNestMembersAttribute extends BoundAttribute<NestMembersAttribute>
 721             implements NestMembersAttribute {
 722 
 723         private List<ClassEntry> members = null;
 724 
 725         public BoundNestMembersAttribute(ClassReader cf, AttributeMapper<NestMembersAttribute> mapper, int pos) {
 726             super(cf, mapper, pos);
 727         }
 728 
 729         @Override
 730         public List<ClassEntry> nestMembers() {
 731             if (members == null) {
 732                 members = readEntryList(payloadStart, ClassEntry.class);
 733             }
 734             return members;
 735         }
 736     }
 737 
 738     public static final class BoundBootstrapMethodsAttribute extends BoundAttribute<BootstrapMethodsAttribute>
 739             implements BootstrapMethodsAttribute {
 740 
 741         private List<BootstrapMethodEntry> bootstraps = null;
 742         private final int size;
 743 
 744         public BoundBootstrapMethodsAttribute(ClassReader reader, AttributeMapper<BootstrapMethodsAttribute> mapper, int pos) {
 745             super(reader, mapper, pos);
 746             size = classReader.readU2(pos);
 747         }
 748 
 749         @Override
 750         public int bootstrapMethodsSize() {
 751             return size;
 752         }
 753 
 754         @Override
 755         public List<BootstrapMethodEntry> bootstrapMethods() {
 756             if (bootstraps == null) {
 757                 BootstrapMethodEntry[] bs = new BootstrapMethodEntry[size];
 758                 int p = payloadStart + 2;
 759                 for (int i = 0; i < size; ++i) {
 760                     final var handle = classReader.readEntry(p, AbstractPoolEntry.MethodHandleEntryImpl.class);
 761                     final List<LoadableConstantEntry> args = readEntryList(p + 2, LoadableConstantEntry.class);
 762                     p += 4 + args.size() * 2;
 763                     int hash = BootstrapMethodEntryImpl.computeHashCode(handle, args);
 764                     bs[i] = new BootstrapMethodEntryImpl(classReader, i, hash, handle, args);
 765                 }
 766                 bootstraps = List.of(bs);
 767             }
 768             return bootstraps;
 769         }
 770     }
 771 
 772     public static final class BoundInnerClassesAttribute extends BoundAttribute<InnerClassesAttribute>
 773             implements InnerClassesAttribute {
 774         private List<InnerClassInfo> classes;
 775 
 776         public BoundInnerClassesAttribute(ClassReader cf, AttributeMapper<InnerClassesAttribute> mapper, int pos) {
 777             super(cf, mapper, pos);
 778         }
 779 
 780         @Override
 781         public List<InnerClassInfo> classes() {
 782             if (classes == null) {
 783                 final int cnt = classReader.readU2(payloadStart);
 784                 int p = payloadStart + 2;
 785                 InnerClassInfo[] elements = new InnerClassInfo[cnt];
 786                 for (int i = 0; i < cnt; i++) {
 787                     ClassEntry innerClass = classReader.readEntry(p, ClassEntry.class);
 788                     var outerClass = classReader.readEntryOrNull(p + 2, ClassEntry.class);
 789                     var innerName = classReader.readEntryOrNull(p + 4, Utf8Entry.class);
 790                     int flags = classReader.readU2(p + 6);
 791                     p += 8;
 792                     elements[i] = InnerClassInfo.of(innerClass, Optional.ofNullable(outerClass), Optional.ofNullable(innerName), flags);
 793                 }
 794                 classes = List.of(elements);
 795             }
 796             return classes;
 797         }
 798     }
 799 
 800     public static final class BoundEnclosingMethodAttribute extends BoundAttribute<EnclosingMethodAttribute>
 801             implements EnclosingMethodAttribute {
 802         public BoundEnclosingMethodAttribute(ClassReader cf, AttributeMapper<EnclosingMethodAttribute> mapper, int pos) {
 803             super(cf, mapper, pos);
 804         }
 805 
 806         @Override
 807         public ClassEntry enclosingClass() {
 808             return classReader.readEntry(payloadStart, ClassEntry.class);
 809         }
 810 
 811         @Override
 812         public Optional<NameAndTypeEntry> enclosingMethod() {
 813             return Optional.ofNullable(classReader.readEntryOrNull(payloadStart + 2, NameAndTypeEntry.class));
 814         }
 815     }
 816 
 817     public static final class BoundAnnotationDefaultAttr
 818             extends BoundAttribute<AnnotationDefaultAttribute>
 819             implements AnnotationDefaultAttribute {
 820         private AnnotationValue annotationValue;
 821 
 822         public BoundAnnotationDefaultAttr(ClassReader cf, AttributeMapper<AnnotationDefaultAttribute> mapper, int pos) {
 823             super(cf, mapper, pos);
 824         }
 825 
 826         @Override
 827         public AnnotationValue defaultValue() {
 828             if (annotationValue == null)
 829                 annotationValue = AnnotationReader.readElementValue(classReader, payloadStart);
 830             return annotationValue;
 831         }
 832     }
 833 
 834     public static final class BoundRuntimeVisibleTypeAnnotationsAttribute extends BoundAttribute<RuntimeVisibleTypeAnnotationsAttribute>
 835             implements RuntimeVisibleTypeAnnotationsAttribute {
 836 
 837         private final LabelContext labelContext;
 838 
 839         public BoundRuntimeVisibleTypeAnnotationsAttribute(AttributedElement enclosing, ClassReader cf, AttributeMapper<RuntimeVisibleTypeAnnotationsAttribute> mapper, int pos) {
 840             super(cf, mapper, pos);
 841             this.labelContext = (enclosing instanceof LabelContext lc) ? lc : null;
 842         }
 843 
 844         @Override
 845         public List<TypeAnnotation> annotations() {
 846             return AnnotationReader.readTypeAnnotations(classReader, payloadStart, labelContext);
 847         }
 848     }
 849 
 850     public static final class BoundRuntimeInvisibleTypeAnnotationsAttribute
 851             extends BoundAttribute<RuntimeInvisibleTypeAnnotationsAttribute>
 852             implements RuntimeInvisibleTypeAnnotationsAttribute {
 853         public BoundRuntimeInvisibleTypeAnnotationsAttribute(AttributedElement enclosing, ClassReader cf, AttributeMapper<RuntimeInvisibleTypeAnnotationsAttribute> mapper, int pos) {
 854             super(cf, mapper, pos);
 855             this.labelContext = (enclosing instanceof LabelContext lc) ? lc : null;
 856         }
 857 
 858         private final LabelContext labelContext;
 859 
 860         @Override
 861         public List<TypeAnnotation> annotations() {
 862             return AnnotationReader.readTypeAnnotations(classReader, payloadStart, labelContext);
 863         }
 864     }
 865 
 866     public static final class BoundRuntimeVisibleParameterAnnotationsAttribute
 867             extends BoundAttribute<RuntimeVisibleParameterAnnotationsAttribute>
 868             implements RuntimeVisibleParameterAnnotationsAttribute {
 869 
 870         public BoundRuntimeVisibleParameterAnnotationsAttribute(ClassReader cf, AttributeMapper<RuntimeVisibleParameterAnnotationsAttribute> mapper, int pos) {
 871             super(cf, mapper, pos);
 872         }
 873 
 874         @Override
 875         public List<List<Annotation>> parameterAnnotations() {
 876             return AnnotationReader.readParameterAnnotations(classReader, payloadStart);
 877         }
 878     }
 879 
 880     public static final class BoundRuntimeInvisibleParameterAnnotationsAttribute
 881             extends BoundAttribute<RuntimeInvisibleParameterAnnotationsAttribute>
 882             implements RuntimeInvisibleParameterAnnotationsAttribute {
 883 
 884         public BoundRuntimeInvisibleParameterAnnotationsAttribute(ClassReader cf, AttributeMapper<RuntimeInvisibleParameterAnnotationsAttribute> mapper, int pos) {
 885             super(cf, mapper, pos);
 886         }
 887 
 888         @Override
 889         public List<List<Annotation>> parameterAnnotations() {
 890             return AnnotationReader.readParameterAnnotations(classReader, payloadStart);
 891         }
 892     }
 893 
 894     public static final class BoundRuntimeInvisibleAnnotationsAttribute
 895             extends BoundAttribute<RuntimeInvisibleAnnotationsAttribute>
 896             implements RuntimeInvisibleAnnotationsAttribute {
 897         private List<Annotation> inflated;
 898 
 899         public BoundRuntimeInvisibleAnnotationsAttribute(ClassReader cf,
 900                                                          int payloadStart) {
 901             super(cf, Attributes.runtimeInvisibleAnnotations(), payloadStart);
 902         }
 903 
 904         @Override
 905         public List<Annotation> annotations() {
 906             if (inflated == null)
 907                 inflated = AnnotationReader.readAnnotations(classReader, payloadStart);
 908             return inflated;
 909         }
 910     }
 911 
 912     public static final class BoundRuntimeVisibleAnnotationsAttribute
 913             extends BoundAttribute<RuntimeVisibleAnnotationsAttribute>
 914             implements RuntimeVisibleAnnotationsAttribute {
 915         private List<Annotation> inflated;
 916 
 917         public BoundRuntimeVisibleAnnotationsAttribute(ClassReader cf,
 918                                                        int payloadStart) {
 919             super(cf, Attributes.runtimeVisibleAnnotations(), payloadStart);
 920         }
 921 
 922         @Override
 923         public List<Annotation> annotations() {
 924             if (inflated == null)
 925                 inflated = AnnotationReader.readAnnotations(classReader, payloadStart);
 926             return inflated;
 927         }
 928     }
 929 
 930     public static final class BoundPermittedSubclassesAttribute extends BoundAttribute<PermittedSubclassesAttribute>
 931             implements PermittedSubclassesAttribute {
 932         private List<ClassEntry> permittedSubclasses = null;
 933 
 934         public BoundPermittedSubclassesAttribute(ClassReader cf, AttributeMapper<PermittedSubclassesAttribute> mapper, int pos) {
 935             super(cf, mapper, pos);
 936         }
 937 
 938         @Override
 939         public List<ClassEntry> permittedSubclasses() {
 940             if (permittedSubclasses == null) {
 941                 permittedSubclasses = readEntryList(payloadStart, ClassEntry.class);
 942             }
 943             return permittedSubclasses;
 944         }
 945     }
 946 
 947     public abstract static sealed class BoundCodeAttribute
 948             extends BoundAttribute<CodeAttribute>
 949             implements CodeAttribute
 950             permits CodeImpl {
 951         protected final int codeStart;
 952         protected final int codeLength;
 953         protected final int codeEnd;
 954         protected final int attributePos;
 955         protected final int exceptionHandlerPos;
 956         protected final int exceptionHandlerCnt;
 957         protected final MethodModel enclosingMethod;
 958 
 959         public BoundCodeAttribute(AttributedElement enclosing,
 960                                   ClassReader reader,
 961                                   AttributeMapper<CodeAttribute> mapper,
 962                                   int payloadStart) {
 963             super(reader, mapper, payloadStart);
 964             this.codeLength = classReader.readInt(payloadStart + 4);
 965             this.enclosingMethod = (MethodModel) enclosing;
 966             this.codeStart = payloadStart + 8;
 967             this.codeEnd = codeStart + codeLength;
 968             this.exceptionHandlerPos = codeEnd;
 969             this.exceptionHandlerCnt = classReader.readU2(exceptionHandlerPos);
 970             this.attributePos = exceptionHandlerPos + 2 + exceptionHandlerCnt * 8;
 971         }
 972 
 973         // CodeAttribute
 974 
 975         @Override
 976         public int maxStack() {
 977             return classReader.readU2(payloadStart);
 978         }
 979 
 980         @Override
 981         public int maxLocals() {
 982             return classReader.readU2(payloadStart + 2);
 983         }
 984 
 985         @Override
 986         public int codeLength() {
 987             return codeLength;
 988         }
 989 
 990         @Override
 991         public byte[] codeArray() {
 992             return classReader.readBytes(payloadStart + 8, codeLength());
 993         }
 994     }
 995 
 996     /**
 997      * {@return the attribute mapper for a standard attribute}
 998      *
 999      * @param name the name of the attribute to find
1000      */
1001     public static AttributeMapper<?> standardAttribute(Utf8Entry name) {
1002         // critical bootstrap path, so no lambdas nor method handles here
1003         return switch (name.hashCode()) {
1004             case 0x46699ff2 ->
1005                 name.equalsString(NAME_ANNOTATION_DEFAULT) ? annotationDefault() : null;
1006             case 0x5208e184 ->
1007                 name.equalsString(NAME_BOOTSTRAP_METHODS) ? bootstrapMethods() : null;
1008             case 0xcb60907a ->
1009                 name.equalsString(NAME_CHARACTER_RANGE_TABLE) ? characterRangeTable() : null;
1010             case 0x4020220d ->
1011                 name.equalsString(NAME_CODE) ? code() : null;
1012             case 0xc20dd1fe ->
1013                 name.equalsString(NAME_COMPILATION_ID) ? compilationId() : null;
1014             case 0xcab1940d ->
1015                 name.equalsString(NAME_CONSTANT_VALUE) ? constantValue() : null;
1016             case 0x558641d3 ->
1017                 name.equalsString(NAME_DEPRECATED) ? deprecated() : null;
1018             case 0x51d443cd ->
1019                 name.equalsString(NAME_ENCLOSING_METHOD) ? enclosingMethod() : null;
1020             case 0x687c1624 ->
1021                 name.equalsString(NAME_EXCEPTIONS) ? exceptions() : null;
1022             case 0x7adb2910 ->
1023                 name.equalsString(NAME_INNER_CLASSES) ? innerClasses() : null;
1024             case 0x653f0551 ->
1025                 name.equalsString(NAME_LINE_NUMBER_TABLE) ? lineNumberTable() : null;
1026             case 0x64c75927 ->
1027                 name.equalsString(NAME_LOCAL_VARIABLE_TABLE) ? localVariableTable() : null;
1028             case 0x6697f98d ->
1029                 name.equalsString(NAME_LOCAL_VARIABLE_TYPE_TABLE) ? localVariableTypeTable() : null;
1030             case 0xdbb0cdcb ->
1031                 name.equalsString(NAME_METHOD_PARAMETERS) ? methodParameters() : null;
1032             case 0xc9b0928c ->
1033                 name.equalsString(NAME_MODULE) ? module() : null;
1034             case 0x41cd27e8 ->
1035                 name.equalsString(NAME_MODULE_HASHES) ? moduleHashes() : null;
1036             case 0x7deb0a13 ->
1037                 name.equalsString(NAME_MODULE_MAIN_CLASS) ? moduleMainClass() : null;
1038             case 0x6706ff99 ->
1039                 name.equalsString(NAME_MODULE_PACKAGES) ? modulePackages() : null;
1040             case 0x60272858 ->
1041                 name.equalsString(NAME_MODULE_RESOLUTION) ? moduleResolution() : null;
1042             case 0x5646d73d ->
1043                 name.equalsString(NAME_MODULE_TARGET) ? moduleTarget() : null;
1044             case 0x50336c40 ->
1045                 name.equalsString(NAME_NEST_HOST) ? nestHost() : null;
1046             case 0x4735ab81 ->
1047                 name.equalsString(NAME_NEST_MEMBERS) ? nestMembers() : null;
1048             case 0x7100d9fe ->
1049                 name.equalsString(NAME_PERMITTED_SUBCLASSES) ? permittedSubclasses() : null;
1050             case 0xd1ab5871 ->
1051                 name.equalsString(NAME_RECORD) ? record() : null;
1052             case 0x7588550f ->
1053                 name.equalsString(NAME_RUNTIME_INVISIBLE_ANNOTATIONS) ? runtimeInvisibleAnnotations() : null;
1054             case 0xcc74da30 ->
1055                 name.equalsString(NAME_RUNTIME_INVISIBLE_PARAMETER_ANNOTATIONS) ? runtimeInvisibleParameterAnnotations() : null;
1056             case 0xf67697f5 ->
1057                 name.equalsString(NAME_RUNTIME_INVISIBLE_TYPE_ANNOTATIONS) ? runtimeInvisibleTypeAnnotations() : null;
1058             case 0xe0837d2a ->
1059                 name.equalsString(NAME_RUNTIME_VISIBLE_ANNOTATIONS) ? runtimeVisibleAnnotations() : null;
1060             case 0xc945a075 ->
1061                 name.equalsString(NAME_RUNTIME_VISIBLE_PARAMETER_ANNOTATIONS) ? runtimeVisibleParameterAnnotations() : null;
1062             case 0x611a3a90 ->
1063                 name.equalsString(NAME_RUNTIME_VISIBLE_TYPE_ANNOTATIONS) ? runtimeVisibleTypeAnnotations() : null;
1064             case 0xf76fb898 ->
1065                 name.equalsString(NAME_SIGNATURE) ? signature() : null;
1066             case 0x6b41b047 ->
1067                 name.equalsString(NAME_SOURCE_DEBUG_EXTENSION) ? sourceDebugExtension() : null;
1068             case 0x748c2857 ->
1069                 name.equalsString(NAME_SOURCE_FILE) ? sourceFile() : null;
1070             case 0x6bf13a96 ->
1071                 name.equalsString(NAME_SOURCE_ID) ? sourceId() : null;
1072             case 0xfa85ee5a ->
1073                 name.equalsString(NAME_STACK_MAP_TABLE) ? stackMapTable() : null;
1074             case 0xf2670725 ->
1075                 name.equalsString(NAME_SYNTHETIC) ? synthetic() : null;
1076             default -> null;
1077         };
1078     }
1079 }