https://projects.eclipse.org/projects/ee4j.jersey/jersey-server: Jersey core server implementation (Eclipse Foundation) 
// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
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//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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package jersey.repackaged.org.objectweb.asm;


A ClassVisitor that generates a corresponding ClassFile structure, as defined in the Java Virtual Machine Specification (JVMS). It can be used alone, to generate a Java class "from scratch", or with one or more ClassReader and adapter ClassVisitor to generate a modified class from one or more existing Java classes. 
Author:Eric Bruneton
See Also:
/**
 * A {@link ClassVisitor} that generates a corresponding ClassFile structure, as defined in the Java
 * Virtual Machine Specification (JVMS). It can be used alone, to generate a Java class "from
 * scratch", or with one or more {@link ClassReader} and adapter {@link ClassVisitor} to generate a
 * modified class from one or more existing Java classes.
 *
 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html">JVMS 4</a>
 * @author Eric Bruneton
 */
public class ClassWriter extends ClassVisitor {

  
A flag to automatically compute the maximum stack size and the maximum number of local variables of methods. If this flag is set, then the arguments of the MethodVisitor.visitMaxs method of the MethodVisitor returned by the visitMethod method will be ignored, and computed automatically from the signature and the bytecode of each method. 
Note: for classes whose version is Opcodes.V1_7 of more, this option requires valid stack map frames. The maximum stack size is then computed from these frames, and from the bytecode instructions in between. If stack map frames are not present or must be recomputed, used COMPUTE_FRAMES instead. 
See Also:
/**
   * A flag to automatically compute the maximum stack size and the maximum number of local
   * variables of methods. If this flag is set, then the arguments of the {@link
   * MethodVisitor#visitMaxs} method of the {@link MethodVisitor} returned by the {@link
   * #visitMethod} method will be ignored, and computed automatically from the signature and the
   * bytecode of each method.
   *
   * <p><b>Note:</b> for classes whose version is {@link Opcodes#V1_7} of more, this option requires
   * valid stack map frames. The maximum stack size is then computed from these frames, and from the
   * bytecode instructions in between. If stack map frames are not present or must be recomputed,
   * used {@link #COMPUTE_FRAMES} instead.
   *
   * @see #ClassWriter(int)
   */
  public static final int COMPUTE_MAXS = 1;

  
A flag to automatically compute the stack map frames of methods from scratch. If this flag is set, then the calls to the MethodVisitor.visitFrame method are ignored, and the stack map frames are recomputed from the methods bytecode. The arguments of the MethodVisitor.visitMaxs method are also ignored and recomputed from the bytecode. In other words, COMPUTE_FRAMES implies COMPUTE_MAXS. 
See Also:
/**
   * A flag to automatically compute the stack map frames of methods from scratch. If this flag is
   * set, then the calls to the {@link MethodVisitor#visitFrame} method are ignored, and the stack
   * map frames are recomputed from the methods bytecode. The arguments of the {@link
   * MethodVisitor#visitMaxs} method are also ignored and recomputed from the bytecode. In other
   * words, {@link #COMPUTE_FRAMES} implies {@link #COMPUTE_MAXS}.
   *
   * @see #ClassWriter(int)
   */
  public static final int COMPUTE_FRAMES = 2;

  // Note: fields are ordered as in the ClassFile structure, and those related to attributes are
  // ordered as in Section 4.7 of the JVMS.

  
The minor_version and major_version fields of the JVMS ClassFile structure. minor_version is
stored in the 16 most significant bits, and major_version in the 16 least significant bits.

/**
   * The minor_version and major_version fields of the JVMS ClassFile structure. minor_version is
   * stored in the 16 most significant bits, and major_version in the 16 least significant bits.
   */
  private int version;

  
The symbol table for this class (contains the constant_pool and the BootstrapMethods). 
/** The symbol table for this class (contains the constant_pool and the BootstrapMethods). */
  private final SymbolTable symbolTable;

  
The access_flags field of the JVMS ClassFile structure. This field can contain ASM specific access flags, such as Opcodes.ACC_DEPRECATED, which are removed when generating the ClassFile structure. 
/**
   * The access_flags field of the JVMS ClassFile structure. This field can contain ASM specific
   * access flags, such as {@link Opcodes#ACC_DEPRECATED}, which are removed when generating the
   * ClassFile structure.
   */
  private int accessFlags;

  
The this_class field of the JVMS ClassFile structure. 
/** The this_class field of the JVMS ClassFile structure. */
  private int thisClass;

  
The super_class field of the JVMS ClassFile structure. 
/** The super_class field of the JVMS ClassFile structure. */
  private int superClass;

  
The interface_count field of the JVMS ClassFile structure. 
/** The interface_count field of the JVMS ClassFile structure. */
  private int interfaceCount;

  
The 'interfaces' array of the JVMS ClassFile structure. 
/** The 'interfaces' array of the JVMS ClassFile structure. */
  private int[] interfaces;

  
The fields of this class, stored in a linked list of FieldWriter linked via their FieldVisitor.fv field. This field stores the first element of this list. 
/**
   * The fields of this class, stored in a linked list of {@link FieldWriter} linked via their
   * {@link FieldWriter#fv} field. This field stores the first element of this list.
   */
  private FieldWriter firstField;

  
The fields of this class, stored in a linked list of FieldWriter linked via their FieldVisitor.fv field. This field stores the last element of this list. 
/**
   * The fields of this class, stored in a linked list of {@link FieldWriter} linked via their
   * {@link FieldWriter#fv} field. This field stores the last element of this list.
   */
  private FieldWriter lastField;

  
The methods of this class, stored in a linked list of MethodWriter linked via their MethodVisitor.mv field. This field stores the first element of this list. 
/**
   * The methods of this class, stored in a linked list of {@link MethodWriter} linked via their
   * {@link MethodWriter#mv} field. This field stores the first element of this list.
   */
  private MethodWriter firstMethod;

  
The methods of this class, stored in a linked list of MethodWriter linked via their MethodVisitor.mv field. This field stores the last element of this list. 
/**
   * The methods of this class, stored in a linked list of {@link MethodWriter} linked via their
   * {@link MethodWriter#mv} field. This field stores the last element of this list.
   */
  private MethodWriter lastMethod;

  
The number_of_classes field of the InnerClasses attribute, or 0. 
/** The number_of_classes field of the InnerClasses attribute, or 0. */
  private int numberOfInnerClasses;

  
The 'classes' array of the InnerClasses attribute, or null. 
/** The 'classes' array of the InnerClasses attribute, or {@literal null}. */
  private ByteVector innerClasses;

  
The class_index field of the EnclosingMethod attribute, or 0. 
/** The class_index field of the EnclosingMethod attribute, or 0. */
  private int enclosingClassIndex;

  
The method_index field of the EnclosingMethod attribute. 
/** The method_index field of the EnclosingMethod attribute. */
  private int enclosingMethodIndex;

  
The signature_index field of the Signature attribute, or 0. 
/** The signature_index field of the Signature attribute, or 0. */
  private int signatureIndex;

  
The source_file_index field of the SourceFile attribute, or 0. 
/** The source_file_index field of the SourceFile attribute, or 0. */
  private int sourceFileIndex;

  
The debug_extension field of the SourceDebugExtension attribute, or null. 
/** The debug_extension field of the SourceDebugExtension attribute, or {@literal null}. */
  private ByteVector debugExtension;

  
The last runtime visible annotation of this class. The previous ones can be accessed with the AnnotationWriter.previousAnnotation field. May be null. 
/**
   * The last runtime visible annotation of this class. The previous ones can be accessed with the
   * {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
   */
  private AnnotationWriter lastRuntimeVisibleAnnotation;

  
The last runtime invisible annotation of this class. The previous ones can be accessed with the AnnotationWriter.previousAnnotation field. May be null. 
/**
   * The last runtime invisible annotation of this class. The previous ones can be accessed with the
   * {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
   */
  private AnnotationWriter lastRuntimeInvisibleAnnotation;

  
The last runtime visible type annotation of this class. The previous ones can be accessed with the AnnotationWriter.previousAnnotation field. May be null. 
/**
   * The last runtime visible type annotation of this class. The previous ones can be accessed with
   * the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
   */
  private AnnotationWriter lastRuntimeVisibleTypeAnnotation;

  
The last runtime invisible type annotation of this class. The previous ones can be accessed with the AnnotationWriter.previousAnnotation field. May be null. 
/**
   * The last runtime invisible type annotation of this class. The previous ones can be accessed
   * with the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
   */
  private AnnotationWriter lastRuntimeInvisibleTypeAnnotation;

  
The Module attribute of this class, or null. 
/** The Module attribute of this class, or {@literal null}. */
  private ModuleWriter moduleWriter;

  
The host_class_index field of the NestHost attribute, or 0. 
/** The host_class_index field of the NestHost attribute, or 0. */
  private int nestHostClassIndex;

  
The number_of_classes field of the NestMembers attribute, or 0. 
/** The number_of_classes field of the NestMembers attribute, or 0. */
  private int numberOfNestMemberClasses;

  
The 'classes' array of the NestMembers attribute, or null. 
/** The 'classes' array of the NestMembers attribute, or {@literal null}. */
  private ByteVector nestMemberClasses;

  
The first non standard attribute of this class. The next ones can be accessed with the Attribute.nextAttribute field. May be null. 
WARNING: this list stores the attributes in the reverse order of their visit. firstAttribute is actually the last attribute visited in visitAttribute. The toByteArray method writes the attributes in the order defined by this list, i.e. in the reverse order specified by the user. 
/**
   * The first non standard attribute of this class. The next ones can be accessed with the {@link
   * Attribute#nextAttribute} field. May be {@literal null}.
   *
   * <p><b>WARNING</b>: this list stores the attributes in the <i>reverse</i> order of their visit.
   * firstAttribute is actually the last attribute visited in {@link #visitAttribute}. The {@link
   * #toByteArray} method writes the attributes in the order defined by this list, i.e. in the
   * reverse order specified by the user.
   */
  private Attribute firstAttribute;

  /**
   * Indicates what must be automatically computed in {@link MethodWriter}. Must be one of {@link
   * MethodWriter#COMPUTE_NOTHING}, {@link MethodWriter#COMPUTE_MAX_STACK_AND_LOCAL}, {@link
   * MethodWriter#COMPUTE_INSERTED_FRAMES}, or {@link MethodWriter#COMPUTE_ALL_FRAMES}.
   */
  private int compute;

  // -----------------------------------------------------------------------------------------------
  // Constructor
  // -----------------------------------------------------------------------------------------------

  
Constructs a new ClassWriter object. 
Params:
  • flags – option flags that can be used to modify the default behavior of this class. Must be zero or more of COMPUTE_MAXS and COMPUTE_FRAMES.
/**
   * Constructs a new {@link ClassWriter} object.
   *
   * @param flags option flags that can be used to modify the default behavior of this class. Must
   *     be zero or more of {@link #COMPUTE_MAXS} and {@link #COMPUTE_FRAMES}.
   */
  public ClassWriter(final int flags) {
    this(null, flags);
  }

  
Constructs a new ClassWriter object and enables optimizations for "mostly add" bytecode transformations. These optimizations are the following: 
    
  
  • The constant pool and bootstrap methods from the original class are copied as is in the
      new class, which saves time. New constant pool entries and new bootstrap methods will be
      added at the end if necessary, but unused constant pool entries or bootstrap methods
      won't be removed.
  
  • Methods that are not transformed are copied as is in the new class, directly from the
      original class bytecode (i.e. without emitting visit events for all the method
      instructions), which saves a lot of time. Untransformed methods are detected by the fact that the ClassReader receives MethodVisitor objects that come from a ClassWriter (and not from any other ClassVisitor instance). 


Params:
  • classReader – the ClassReader used to read the original class. It will be used to copy the entire constant pool and bootstrap methods from the original class and also to copy other fragments of original bytecode where applicable.
  • flags – option flags that can be used to modify the default behavior of this class.Must be zero or more of COMPUTE_MAXS and COMPUTE_FRAMES. These option flags do
    not affect methods that are copied as is in the new class. This means that neither the
    maximum stack size nor the stack frames will be computed for these methods.
/**
   * Constructs a new {@link ClassWriter} object and enables optimizations for "mostly add" bytecode
   * transformations. These optimizations are the following:
   *
   * <ul>
   *   <li>The constant pool and bootstrap methods from the original class are copied as is in the
   *       new class, which saves time. New constant pool entries and new bootstrap methods will be
   *       added at the end if necessary, but unused constant pool entries or bootstrap methods
   *       <i>won't be removed</i>.
   *   <li>Methods that are not transformed are copied as is in the new class, directly from the
   *       original class bytecode (i.e. without emitting visit events for all the method
   *       instructions), which saves a <i>lot</i> of time. Untransformed methods are detected by
   *       the fact that the {@link ClassReader} receives {@link MethodVisitor} objects that come
   *       from a {@link ClassWriter} (and not from any other {@link ClassVisitor} instance).
   * </ul>
   *
   * @param classReader the {@link ClassReader} used to read the original class. It will be used to
   *     copy the entire constant pool and bootstrap methods from the original class and also to
   *     copy other fragments of original bytecode where applicable.
   * @param flags option flags that can be used to modify the default behavior of this class.Must be
   *     zero or more of {@link #COMPUTE_MAXS} and {@link #COMPUTE_FRAMES}. <i>These option flags do
   *     not affect methods that are copied as is in the new class. This means that neither the
   *     maximum stack size nor the stack frames will be computed for these methods</i>.
   */
  public ClassWriter(final ClassReader classReader, final int flags) {
    super(Opcodes.ASM7);
    symbolTable = classReader == null ? new SymbolTable(this) : new SymbolTable(this, classReader);
    if ((flags & COMPUTE_FRAMES) != 0) {
      this.compute = MethodWriter.COMPUTE_ALL_FRAMES;
    } else if ((flags & COMPUTE_MAXS) != 0) {
      this.compute = MethodWriter.COMPUTE_MAX_STACK_AND_LOCAL;
    } else {
      this.compute = MethodWriter.COMPUTE_NOTHING;
    }
  }

  // -----------------------------------------------------------------------------------------------
  // Implementation of the ClassVisitor abstract class
  // -----------------------------------------------------------------------------------------------

  @Override
  public final void visit(
      final int version,
      final int access,
      final String name,
      final String signature,
      final String superName,
      final String[] interfaces) {
    this.version = version;
    this.accessFlags = access;
    this.thisClass = symbolTable.setMajorVersionAndClassName(version & 0xFFFF, name);
    if (signature != null) {
      this.signatureIndex = symbolTable.addConstantUtf8(signature);
    }
    this.superClass = superName == null ? 0 : symbolTable.addConstantClass(superName).index;
    if (interfaces != null && interfaces.length > 0) {
      interfaceCount = interfaces.length;
      this.interfaces = new int[interfaceCount];
      for (int i = 0; i < interfaceCount; ++i) {
        this.interfaces[i] = symbolTable.addConstantClass(interfaces[i]).index;
      }
    }
    if (compute == MethodWriter.COMPUTE_MAX_STACK_AND_LOCAL && (version & 0xFFFF) >= Opcodes.V1_7) {
      compute = MethodWriter.COMPUTE_MAX_STACK_AND_LOCAL_FROM_FRAMES;
    }
  }

  @Override
  public final void visitSource(final String file, final String debug) {
    if (file != null) {
      sourceFileIndex = symbolTable.addConstantUtf8(file);
    }
    if (debug != null) {
      debugExtension = new ByteVector().encodeUtf8(debug, 0, Integer.MAX_VALUE);
    }
  }

  @Override
  public final ModuleVisitor visitModule(
      final String name, final int access, final String version) {
    return moduleWriter =
        new ModuleWriter(
            symbolTable,
            symbolTable.addConstantModule(name).index,
            access,
            version == null ? 0 : symbolTable.addConstantUtf8(version));
  }

  @Override
  public final void visitNestHost(final String nestHost) {
    nestHostClassIndex = symbolTable.addConstantClass(nestHost).index;
  }

  @Override
  public final void visitOuterClass(
      final String owner, final String name, final String descriptor) {
    enclosingClassIndex = symbolTable.addConstantClass(owner).index;
    if (name != null && descriptor != null) {
      enclosingMethodIndex = symbolTable.addConstantNameAndType(name, descriptor);
    }
  }

  @Override
  public final AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
    if (visible) {
      return lastRuntimeVisibleAnnotation =
          AnnotationWriter.create(symbolTable, descriptor, lastRuntimeVisibleAnnotation);
    } else {
      return lastRuntimeInvisibleAnnotation =
          AnnotationWriter.create(symbolTable, descriptor, lastRuntimeInvisibleAnnotation);
    }
  }

  @Override
  public final AnnotationVisitor visitTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    if (visible) {
      return lastRuntimeVisibleTypeAnnotation =
          AnnotationWriter.create(
              symbolTable, typeRef, typePath, descriptor, lastRuntimeVisibleTypeAnnotation);
    } else {
      return lastRuntimeInvisibleTypeAnnotation =
          AnnotationWriter.create(
              symbolTable, typeRef, typePath, descriptor, lastRuntimeInvisibleTypeAnnotation);
    }
  }

  @Override
  public final void visitAttribute(final Attribute attribute) {
    // Store the attributes in the <i>reverse</i> order of their visit by this method.
    attribute.nextAttribute = firstAttribute;
    firstAttribute = attribute;
  }

  @Override
  public final void visitNestMember(final String nestMember) {
    if (nestMemberClasses == null) {
      nestMemberClasses = new ByteVector();
    }
    ++numberOfNestMemberClasses;
    nestMemberClasses.putShort(symbolTable.addConstantClass(nestMember).index);
  }

  @Override
  public final void visitInnerClass(
      final String name, final String outerName, final String innerName, final int access) {
    if (innerClasses == null) {
      innerClasses = new ByteVector();
    }
    // Section 4.7.6 of the JVMS states "Every CONSTANT_Class_info entry in the constant_pool table
    // which represents a class or interface C that is not a package member must have exactly one
    // corresponding entry in the classes array". To avoid duplicates we keep track in the info
    // field of the Symbol of each CONSTANT_Class_info entry C whether an inner class entry has
    // already been added for C. If so, we store the index of this inner class entry (plus one) in
    // the info field. This trick allows duplicate detection in O(1) time.
    Symbol nameSymbol = symbolTable.addConstantClass(name);
    if (nameSymbol.info == 0) {
      ++numberOfInnerClasses;
      innerClasses.putShort(nameSymbol.index);
      innerClasses.putShort(outerName == null ? 0 : symbolTable.addConstantClass(outerName).index);
      innerClasses.putShort(innerName == null ? 0 : symbolTable.addConstantUtf8(innerName));
      innerClasses.putShort(access);
      nameSymbol.info = numberOfInnerClasses;
    }
    // Else, compare the inner classes entry nameSymbol.info - 1 with the arguments of this method
    // and throw an exception if there is a difference?
  }

  @Override
  public final FieldVisitor visitField(
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final Object value) {
    FieldWriter fieldWriter =
        new FieldWriter(symbolTable, access, name, descriptor, signature, value);
    if (firstField == null) {
      firstField = fieldWriter;
    } else {
      lastField.fv = fieldWriter;
    }
    return lastField = fieldWriter;
  }

  @Override
  public final MethodVisitor visitMethod(
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final String[] exceptions) {
    MethodWriter methodWriter =
        new MethodWriter(symbolTable, access, name, descriptor, signature, exceptions, compute);
    if (firstMethod == null) {
      firstMethod = methodWriter;
    } else {
      lastMethod.mv = methodWriter;
    }
    return lastMethod = methodWriter;
  }

  @Override
  public final void visitEnd() {
    // Nothing to do.
  }

  // -----------------------------------------------------------------------------------------------
  // Other public methods
  // -----------------------------------------------------------------------------------------------

  
Returns the content of the class file that was built by this ClassWriter.

Throws:
Returns:the binary content of the JVMS ClassFile structure that was built by this ClassWriter.
/**
   * Returns the content of the class file that was built by this ClassWriter.
   *
   * @return the binary content of the JVMS ClassFile structure that was built by this ClassWriter.
   * @throws ClassTooLargeException if the constant pool of the class is too large.
   * @throws MethodTooLargeException if the Code attribute of a method is too large.
   */
  public byte[] toByteArray() {
    // First step: compute the size in bytes of the ClassFile structure.
    // The magic field uses 4 bytes, 10 mandatory fields (minor_version, major_version,
    // constant_pool_count, access_flags, this_class, super_class, interfaces_count, fields_count,
    // methods_count and attributes_count) use 2 bytes each, and each interface uses 2 bytes too.
    int size = 24 + 2 * interfaceCount;
    int fieldsCount = 0;
    FieldWriter fieldWriter = firstField;
    while (fieldWriter != null) {
      ++fieldsCount;
      size += fieldWriter.computeFieldInfoSize();
      fieldWriter = (FieldWriter) fieldWriter.fv;
    }
    int methodsCount = 0;
    MethodWriter methodWriter = firstMethod;
    while (methodWriter != null) {
      ++methodsCount;
      size += methodWriter.computeMethodInfoSize();
      methodWriter = (MethodWriter) methodWriter.mv;
    }
    // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
    int attributesCount = 0;
    if (innerClasses != null) {
      ++attributesCount;
      size += 8 + innerClasses.length;
      symbolTable.addConstantUtf8(Constants.INNER_CLASSES);
    }
    if (enclosingClassIndex != 0) {
      ++attributesCount;
      size += 10;
      symbolTable.addConstantUtf8(Constants.ENCLOSING_METHOD);
    }
    if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && (version & 0xFFFF) < Opcodes.V1_5) {
      ++attributesCount;
      size += 6;
      symbolTable.addConstantUtf8(Constants.SYNTHETIC);
    }
    if (signatureIndex != 0) {
      ++attributesCount;
      size += 8;
      symbolTable.addConstantUtf8(Constants.SIGNATURE);
    }
    if (sourceFileIndex != 0) {
      ++attributesCount;
      size += 8;
      symbolTable.addConstantUtf8(Constants.SOURCE_FILE);
    }
    if (debugExtension != null) {
      ++attributesCount;
      size += 6 + debugExtension.length;
      symbolTable.addConstantUtf8(Constants.SOURCE_DEBUG_EXTENSION);
    }
    if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
      ++attributesCount;
      size += 6;
      symbolTable.addConstantUtf8(Constants.DEPRECATED);
    }
    if (lastRuntimeVisibleAnnotation != null) {
      ++attributesCount;
      size +=
          lastRuntimeVisibleAnnotation.computeAnnotationsSize(
              Constants.RUNTIME_VISIBLE_ANNOTATIONS);
    }
    if (lastRuntimeInvisibleAnnotation != null) {
      ++attributesCount;
      size +=
          lastRuntimeInvisibleAnnotation.computeAnnotationsSize(
              Constants.RUNTIME_INVISIBLE_ANNOTATIONS);
    }
    if (lastRuntimeVisibleTypeAnnotation != null) {
      ++attributesCount;
      size +=
          lastRuntimeVisibleTypeAnnotation.computeAnnotationsSize(
              Constants.RUNTIME_VISIBLE_TYPE_ANNOTATIONS);
    }
    if (lastRuntimeInvisibleTypeAnnotation != null) {
      ++attributesCount;
      size +=
          lastRuntimeInvisibleTypeAnnotation.computeAnnotationsSize(
              Constants.RUNTIME_INVISIBLE_TYPE_ANNOTATIONS);
    }
    if (symbolTable.computeBootstrapMethodsSize() > 0) {
      ++attributesCount;
      size += symbolTable.computeBootstrapMethodsSize();
    }
    if (moduleWriter != null) {
      attributesCount += moduleWriter.getAttributeCount();
      size += moduleWriter.computeAttributesSize();
    }
    if (nestHostClassIndex != 0) {
      ++attributesCount;
      size += 8;
      symbolTable.addConstantUtf8(Constants.NEST_HOST);
    }
    if (nestMemberClasses != null) {
      ++attributesCount;
      size += 8 + nestMemberClasses.length;
      symbolTable.addConstantUtf8(Constants.NEST_MEMBERS);
    }
    if (firstAttribute != null) {
      attributesCount += firstAttribute.getAttributeCount();
      size += firstAttribute.computeAttributesSize(symbolTable);
    }
    // IMPORTANT: this must be the last part of the ClassFile size computation, because the previous
    // statements can add attribute names to the constant pool, thereby changing its size!
    size += symbolTable.getConstantPoolLength();
    int constantPoolCount = symbolTable.getConstantPoolCount();
    if (constantPoolCount > 0xFFFF) {
      throw new ClassTooLargeException(symbolTable.getClassName(), constantPoolCount);
    }

    // Second step: allocate a ByteVector of the correct size (in order to avoid any array copy in
    // dynamic resizes) and fill it with the ClassFile content.
    ByteVector result = new ByteVector(size);
    result.putInt(0xCAFEBABE).putInt(version);
    symbolTable.putConstantPool(result);
    int mask = (version & 0xFFFF) < Opcodes.V1_5 ? Opcodes.ACC_SYNTHETIC : 0;
    result.putShort(accessFlags & ~mask).putShort(thisClass).putShort(superClass);
    result.putShort(interfaceCount);
    for (int i = 0; i < interfaceCount; ++i) {
      result.putShort(interfaces[i]);
    }
    result.putShort(fieldsCount);
    fieldWriter = firstField;
    while (fieldWriter != null) {
      fieldWriter.putFieldInfo(result);
      fieldWriter = (FieldWriter) fieldWriter.fv;
    }
    result.putShort(methodsCount);
    boolean hasFrames = false;
    boolean hasAsmInstructions = false;
    methodWriter = firstMethod;
    while (methodWriter != null) {
      hasFrames |= methodWriter.hasFrames();
      hasAsmInstructions |= methodWriter.hasAsmInstructions();
      methodWriter.putMethodInfo(result);
      methodWriter = (MethodWriter) methodWriter.mv;
    }
    // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
    result.putShort(attributesCount);
    if (innerClasses != null) {
      result
          .putShort(symbolTable.addConstantUtf8(Constants.INNER_CLASSES))
          .putInt(innerClasses.length + 2)
          .putShort(numberOfInnerClasses)
          .putByteArray(innerClasses.data, 0, innerClasses.length);
    }
    if (enclosingClassIndex != 0) {
      result
          .putShort(symbolTable.addConstantUtf8(Constants.ENCLOSING_METHOD))
          .putInt(4)
          .putShort(enclosingClassIndex)
          .putShort(enclosingMethodIndex);
    }
    if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && (version & 0xFFFF) < Opcodes.V1_5) {
      result.putShort(symbolTable.addConstantUtf8(Constants.SYNTHETIC)).putInt(0);
    }
    if (signatureIndex != 0) {
      result
          .putShort(symbolTable.addConstantUtf8(Constants.SIGNATURE))
          .putInt(2)
          .putShort(signatureIndex);
    }
    if (sourceFileIndex != 0) {
      result
          .putShort(symbolTable.addConstantUtf8(Constants.SOURCE_FILE))
          .putInt(2)
          .putShort(sourceFileIndex);
    }
    if (debugExtension != null) {
      int length = debugExtension.length;
      result
          .putShort(symbolTable.addConstantUtf8(Constants.SOURCE_DEBUG_EXTENSION))
          .putInt(length)
          .putByteArray(debugExtension.data, 0, length);
    }
    if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
      result.putShort(symbolTable.addConstantUtf8(Constants.DEPRECATED)).putInt(0);
    }
    AnnotationWriter.putAnnotations(
        symbolTable,
        lastRuntimeVisibleAnnotation,
        lastRuntimeInvisibleAnnotation,
        lastRuntimeVisibleTypeAnnotation,
        lastRuntimeInvisibleTypeAnnotation,
        result);
    symbolTable.putBootstrapMethods(result);
    if (moduleWriter != null) {
      moduleWriter.putAttributes(result);
    }
    if (nestHostClassIndex != 0) {
      result
          .putShort(symbolTable.addConstantUtf8(Constants.NEST_HOST))
          .putInt(2)
          .putShort(nestHostClassIndex);
    }
    if (nestMemberClasses != null) {
      result
          .putShort(symbolTable.addConstantUtf8(Constants.NEST_MEMBERS))
          .putInt(nestMemberClasses.length + 2)
          .putShort(numberOfNestMemberClasses)
          .putByteArray(nestMemberClasses.data, 0, nestMemberClasses.length);
    }
    if (firstAttribute != null) {
      firstAttribute.putAttributes(symbolTable, result);
    }

    // Third step: replace the ASM specific instructions, if any.
    if (hasAsmInstructions) {
      return replaceAsmInstructions(result.data, hasFrames);
    } else {
      return result.data;
    }
  }

  
Returns the equivalent of the given class file, with the ASM specific instructions replaced
with standard ones. This is done with a ClassReader -> ClassWriter round trip.

Params:
  • classFile – a class file containing ASM specific instructions, generated by this
    ClassWriter.
  • hasFrames – whether there is at least one stack map frames in 'classFile'.
Returns:an equivalent of 'classFile', with the ASM specific instructions replaced with standard
    ones.
/**
   * Returns the equivalent of the given class file, with the ASM specific instructions replaced
   * with standard ones. This is done with a ClassReader -&gt; ClassWriter round trip.
   *
   * @param classFile a class file containing ASM specific instructions, generated by this
   *     ClassWriter.
   * @param hasFrames whether there is at least one stack map frames in 'classFile'.
   * @return an equivalent of 'classFile', with the ASM specific instructions replaced with standard
   *     ones.
   */
  private byte[] replaceAsmInstructions(final byte[] classFile, final boolean hasFrames) {
    final Attribute[] attributes = getAttributePrototypes();
    firstField = null;
    lastField = null;
    firstMethod = null;
    lastMethod = null;
    lastRuntimeVisibleAnnotation = null;
    lastRuntimeInvisibleAnnotation = null;
    lastRuntimeVisibleTypeAnnotation = null;
    lastRuntimeInvisibleTypeAnnotation = null;
    moduleWriter = null;
    nestHostClassIndex = 0;
    numberOfNestMemberClasses = 0;
    nestMemberClasses = null;
    firstAttribute = null;
    compute = hasFrames ? MethodWriter.COMPUTE_INSERTED_FRAMES : MethodWriter.COMPUTE_NOTHING;
    new ClassReader(classFile, 0, /* checkClassVersion = */ false)
        .accept(
            this,
            attributes,
            (hasFrames ? ClassReader.EXPAND_FRAMES : 0) | ClassReader.EXPAND_ASM_INSNS);
    return toByteArray();
  }

  
Returns the prototypes of the attributes used by this class, its fields and its methods.

Returns:the prototypes of the attributes used by this class, its fields and its methods.
/**
   * Returns the prototypes of the attributes used by this class, its fields and its methods.
   *
   * @return the prototypes of the attributes used by this class, its fields and its methods.
   */
  private Attribute[] getAttributePrototypes() {
    Attribute.Set attributePrototypes = new Attribute.Set();
    attributePrototypes.addAttributes(firstAttribute);
    FieldWriter fieldWriter = firstField;
    while (fieldWriter != null) {
      fieldWriter.collectAttributePrototypes(attributePrototypes);
      fieldWriter = (FieldWriter) fieldWriter.fv;
    }
    MethodWriter methodWriter = firstMethod;
    while (methodWriter != null) {
      methodWriter.collectAttributePrototypes(attributePrototypes);
      methodWriter = (MethodWriter) methodWriter.mv;
    }
    return attributePrototypes.toArray();
  }

  // -----------------------------------------------------------------------------------------------
  // Utility methods: constant pool management for Attribute sub classes
  // -----------------------------------------------------------------------------------------------

  
Adds a number or string constant to the constant pool of the class being build. Does nothing if
the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • value – the value of the constant to be added to the constant pool. This parameter must be an Integer, a Float, a Long, a Double or a String.
Returns:the index of a new or already existing constant item with the given value.
/**
   * Adds a number or string constant to the constant pool of the class being build. Does nothing if
   * the constant pool already contains a similar item. <i>This method is intended for {@link
   * Attribute} sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param value the value of the constant to be added to the constant pool. This parameter must be
   *     an {@link Integer}, a {@link Float}, a {@link Long}, a {@link Double} or a {@link String}.
   * @return the index of a new or already existing constant item with the given value.
   */
  public int newConst(final Object value) {
    return symbolTable.addConstant(value).index;
  }

  
Adds an UTF8 string to the constant pool of the class being build. Does nothing if the constant
pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • value – the String value.
Returns:the index of a new or already existing UTF8 item.
/**
   * Adds an UTF8 string to the constant pool of the class being build. Does nothing if the constant
   * pool already contains a similar item. <i>This method is intended for {@link Attribute} sub
   * classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param value the String value.
   * @return the index of a new or already existing UTF8 item.
   */
  // DontCheck(AbbreviationAsWordInName): can't be renamed (for backward binary compatibility).
  public int newUTF8(final String value) {
    return symbolTable.addConstantUtf8(value);
  }

  
Adds a class reference to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • value – the internal name of the class.
Returns:the index of a new or already existing class reference item.
/**
   * Adds a class reference to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param value the internal name of the class.
   * @return the index of a new or already existing class reference item.
   */
  public int newClass(final String value) {
    return symbolTable.addConstantClass(value).index;
  }

  
Adds a method type reference to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • methodDescriptor – method descriptor of the method type.
Returns:the index of a new or already existing method type reference item.
/**
   * Adds a method type reference to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param methodDescriptor method descriptor of the method type.
   * @return the index of a new or already existing method type reference item.
   */
  public int newMethodType(final String methodDescriptor) {
    return symbolTable.addConstantMethodType(methodDescriptor).index;
  }

  
Adds a module reference to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • moduleName – name of the module.
Returns:the index of a new or already existing module reference item.
/**
   * Adds a module reference to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param moduleName name of the module.
   * @return the index of a new or already existing module reference item.
   */
  public int newModule(final String moduleName) {
    return symbolTable.addConstantModule(moduleName).index;
  }

  
Adds a package reference to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • packageName – name of the package in its internal form.
Returns:the index of a new or already existing module reference item.
/**
   * Adds a package reference to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param packageName name of the package in its internal form.
   * @return the index of a new or already existing module reference item.
   */
  public int newPackage(final String packageName) {
    return symbolTable.addConstantPackage(packageName).index;
  }

  
Adds a handle to the constant pool of the class being build. Does nothing if the constant pool
already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
Returns:the index of a new or already existing method type reference item.
Deprecated:this method is superseded by newHandle(int, String, String, String, boolean).
/**
   * Adds a handle to the constant pool of the class being build. Does nothing if the constant pool
   * already contains a similar item. <i>This method is intended for {@link Attribute} sub classes,
   * and is normally not needed by class generators or adapters.</i>
   *
   * @param tag the kind of this handle. Must be {@link Opcodes#H_GETFIELD}, {@link
   *     Opcodes#H_GETSTATIC}, {@link Opcodes#H_PUTFIELD}, {@link Opcodes#H_PUTSTATIC}, {@link
   *     Opcodes#H_INVOKEVIRTUAL}, {@link Opcodes#H_INVOKESTATIC}, {@link Opcodes#H_INVOKESPECIAL},
   *     {@link Opcodes#H_NEWINVOKESPECIAL} or {@link Opcodes#H_INVOKEINTERFACE}.
   * @param owner the internal name of the field or method owner class.
   * @param name the name of the field or method.
   * @param descriptor the descriptor of the field or method.
   * @return the index of a new or already existing method type reference item.
   * @deprecated this method is superseded by {@link #newHandle(int, String, String, String,
   *     boolean)}.
   */
  @Deprecated
  public int newHandle(
      final int tag, final String owner, final String name, final String descriptor) {
    return newHandle(tag, owner, name, descriptor, tag == Opcodes.H_INVOKEINTERFACE);
  }

  
Adds a handle to the constant pool of the class being build. Does nothing if the constant pool
already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
Returns:the index of a new or already existing method type reference item.
/**
   * Adds a handle to the constant pool of the class being build. Does nothing if the constant pool
   * already contains a similar item. <i>This method is intended for {@link Attribute} sub classes,
   * and is normally not needed by class generators or adapters.</i>
   *
   * @param tag the kind of this handle. Must be {@link Opcodes#H_GETFIELD}, {@link
   *     Opcodes#H_GETSTATIC}, {@link Opcodes#H_PUTFIELD}, {@link Opcodes#H_PUTSTATIC}, {@link
   *     Opcodes#H_INVOKEVIRTUAL}, {@link Opcodes#H_INVOKESTATIC}, {@link Opcodes#H_INVOKESPECIAL},
   *     {@link Opcodes#H_NEWINVOKESPECIAL} or {@link Opcodes#H_INVOKEINTERFACE}.
   * @param owner the internal name of the field or method owner class.
   * @param name the name of the field or method.
   * @param descriptor the descriptor of the field or method.
   * @param isInterface true if the owner is an interface.
   * @return the index of a new or already existing method type reference item.
   */
  public int newHandle(
      final int tag,
      final String owner,
      final String name,
      final String descriptor,
      final boolean isInterface) {
    return symbolTable.addConstantMethodHandle(tag, owner, name, descriptor, isInterface).index;
  }

  
Adds a dynamic constant reference to the constant pool of the class being build. Does nothing
if the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • name – name of the invoked method.
  • descriptor – field descriptor of the constant type.
  • bootstrapMethodHandle – the bootstrap method.
  • bootstrapMethodArguments – the bootstrap method constant arguments.
Returns:the index of a new or already existing dynamic constant reference item.
/**
   * Adds a dynamic constant reference to the constant pool of the class being build. Does nothing
   * if the constant pool already contains a similar item. <i>This method is intended for {@link
   * Attribute} sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param name name of the invoked method.
   * @param descriptor field descriptor of the constant type.
   * @param bootstrapMethodHandle the bootstrap method.
   * @param bootstrapMethodArguments the bootstrap method constant arguments.
   * @return the index of a new or already existing dynamic constant reference item.
   */
  public int newConstantDynamic(
      final String name,
      final String descriptor,
      final Handle bootstrapMethodHandle,
      final Object... bootstrapMethodArguments) {
    return symbolTable.addConstantDynamic(
            name, descriptor, bootstrapMethodHandle, bootstrapMethodArguments)
        .index;
  }

  
Adds an invokedynamic reference to the constant pool of the class being build. Does nothing if
the constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • name – name of the invoked method.
  • descriptor – descriptor of the invoke method.
  • bootstrapMethodHandle – the bootstrap method.
  • bootstrapMethodArguments – the bootstrap method constant arguments.
Returns:the index of a new or already existing invokedynamic reference item.
/**
   * Adds an invokedynamic reference to the constant pool of the class being build. Does nothing if
   * the constant pool already contains a similar item. <i>This method is intended for {@link
   * Attribute} sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param name name of the invoked method.
   * @param descriptor descriptor of the invoke method.
   * @param bootstrapMethodHandle the bootstrap method.
   * @param bootstrapMethodArguments the bootstrap method constant arguments.
   * @return the index of a new or already existing invokedynamic reference item.
   */
  public int newInvokeDynamic(
      final String name,
      final String descriptor,
      final Handle bootstrapMethodHandle,
      final Object... bootstrapMethodArguments) {
    return symbolTable.addConstantInvokeDynamic(
            name, descriptor, bootstrapMethodHandle, bootstrapMethodArguments)
        .index;
  }

  
Adds a field reference to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • owner – the internal name of the field's owner class.
  • name – the field's name.
  • descriptor – the field's descriptor.
Returns:the index of a new or already existing field reference item.
/**
   * Adds a field reference to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param owner the internal name of the field's owner class.
   * @param name the field's name.
   * @param descriptor the field's descriptor.
   * @return the index of a new or already existing field reference item.
   */
  public int newField(final String owner, final String name, final String descriptor) {
    return symbolTable.addConstantFieldref(owner, name, descriptor).index;
  }

  
Adds a method reference to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • owner – the internal name of the method's owner class.
  • name – the method's name.
  • descriptor – the method's descriptor.
  • isInterface – true if owner is an interface.
Returns:the index of a new or already existing method reference item.
/**
   * Adds a method reference to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param owner the internal name of the method's owner class.
   * @param name the method's name.
   * @param descriptor the method's descriptor.
   * @param isInterface {@literal true} if {@code owner} is an interface.
   * @return the index of a new or already existing method reference item.
   */
  public int newMethod(
      final String owner, final String name, final String descriptor, final boolean isInterface) {
    return symbolTable.addConstantMethodref(owner, name, descriptor, isInterface).index;
  }

  
Adds a name and type to the constant pool of the class being build. Does nothing if the
constant pool already contains a similar item. This method is intended for Attribute sub classes, and is normally not needed by class generators or adapters.

Params:
  • name – a name.
  • descriptor – a type descriptor.
Returns:the index of a new or already existing name and type item.
/**
   * Adds a name and type to the constant pool of the class being build. Does nothing if the
   * constant pool already contains a similar item. <i>This method is intended for {@link Attribute}
   * sub classes, and is normally not needed by class generators or adapters.</i>
   *
   * @param name a name.
   * @param descriptor a type descriptor.
   * @return the index of a new or already existing name and type item.
   */
  public int newNameType(final String name, final String descriptor) {
    return symbolTable.addConstantNameAndType(name, descriptor);
  }

  // -----------------------------------------------------------------------------------------------
  // Default method to compute common super classes when computing stack map frames
  // -----------------------------------------------------------------------------------------------

  
Returns the common super type of the two given types. The default implementation of this method
loads the two given classes and uses the java.lang.Class methods to find the common
super class. It can be overridden to compute this common super type in other ways, in
particular without actually loading any class, or to take into account the class that is
currently being generated by this ClassWriter, which can of course not be loaded since it is
under construction.

Params:
  • type1 – the internal name of a class.
  • type2 – the internal name of another class.
Returns:the internal name of the common super class of the two given classes.
/**
   * Returns the common super type of the two given types. The default implementation of this method
   * <i>loads</i> the two given classes and uses the java.lang.Class methods to find the common
   * super class. It can be overridden to compute this common super type in other ways, in
   * particular without actually loading any class, or to take into account the class that is
   * currently being generated by this ClassWriter, which can of course not be loaded since it is
   * under construction.
   *
   * @param type1 the internal name of a class.
   * @param type2 the internal name of another class.
   * @return the internal name of the common super class of the two given classes.
   */
  protected String getCommonSuperClass(final String type1, final String type2) {
    ClassLoader classLoader = getClassLoader();
    Class<?> class1;
    try {
      class1 = Class.forName(type1.replace('/', '.'), false, classLoader);
    } catch (ClassNotFoundException e) {
      throw new TypeNotPresentException(type1, e);
    }
    Class<?> class2;
    try {
      class2 = Class.forName(type2.replace('/', '.'), false, classLoader);
    } catch (ClassNotFoundException e) {
      throw new TypeNotPresentException(type2, e);
    }
    if (class1.isAssignableFrom(class2)) {
      return type1;
    }
    if (class2.isAssignableFrom(class1)) {
      return type2;
    }
    if (class1.isInterface() || class2.isInterface()) {
      return "java/lang/Object";
    } else {
      do {
        class1 = class1.getSuperclass();
      } while (!class1.isAssignableFrom(class2));
      return class1.getName().replace('.', '/');
    }
  }

  
Returns the ClassLoader to be used by the default implementation of getCommonSuperClass(String, String), that of this ClassWriter's runtime type by default. 
Returns:ClassLoader
/**
   * Returns the {@link ClassLoader} to be used by the default implementation of {@link
   * #getCommonSuperClass(String, String)}, that of this {@link ClassWriter}'s runtime type by
   * default.
   *
   * @return ClassLoader
   */
  protected ClassLoader getClassLoader() {
    return getClass().getClassLoader();
  }
}