// 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
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
package scala.tools.asm.util;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import scala.tools.asm.Attribute;
import scala.tools.asm.ConstantDynamic;
import scala.tools.asm.Handle;
import scala.tools.asm.Label;
import scala.tools.asm.Opcodes;
import scala.tools.asm.Type;
import scala.tools.asm.TypePath;
import scala.tools.asm.TypeReference;
import scala.tools.asm.signature.SignatureReader;

/**
 * A {@link Printer} that prints a disassembled view of the classes it visits.
 *
 * @author Eric Bruneton
 */
public class Textifier extends Printer {

  /** The help message shown when command line arguments are incorrect. */
  private static final String USAGE =
      "Prints a disassembled view of the given class.\n"
          + "Usage: Textifier [-nodebug] <fully qualified class name or class file name>";

  /**
   * The type of internal names (see {@link Type#getInternalName()}). See {@link #appendDescriptor}.
   */
  public static final int INTERNAL_NAME = 0;

  /** The type of field descriptors. See {@link #appendDescriptor}. */
  public static final int FIELD_DESCRIPTOR = 1;

  /** The type of field signatures. See {@link #appendDescriptor}. */
  public static final int FIELD_SIGNATURE = 2;

  /** The type of method descriptors. See {@link #appendDescriptor}. */
  public static final int METHOD_DESCRIPTOR = 3;

  /** The type of method signatures. See {@link #appendDescriptor}. */
  public static final int METHOD_SIGNATURE = 4;

  /** The type of class signatures. See {@link #appendDescriptor}. */
  public static final int CLASS_SIGNATURE = 5;

  /** The type of method handle descriptors. See {@link #appendDescriptor}. */
  public static final int HANDLE_DESCRIPTOR = 9;

  private static final String CLASS_SUFFIX = ".class";
  private static final String DEPRECATED = "// DEPRECATED\n";
  private static final String RECORD = "// RECORD\n";
  private static final String INVISIBLE = " // invisible\n";

  private static final List<String> FRAME_TYPES =
      Collections.unmodifiableList(Arrays.asList("T", "I", "F", "D", "J", "N", "U"));

  /** The indentation of class members at depth level 1 (e.g. fields, methods). */
  protected String tab = "  ";

  /** The indentation of class elements at depth level 2 (e.g. bytecode instructions in methods). */
  protected String tab2 = "    ";

  /** The indentation of class elements at depth level 3 (e.g. switch cases in methods). */
  protected String tab3 = "      ";

  /** The indentation of labels. */
  protected String ltab = "   ";

  /** The names of the labels. */
  protected Map<Label, String> labelNames;

  /** The access flags of the visited class. */
  private int access;

  /** The number of annotation values visited so far. */
  private int numAnnotationValues;

  /**
   * Constructs a new {@link Textifier}. <i>Subclasses must not use this constructor</i>. Instead,
   * they must use the {@link #Textifier(int)} version.
   *
   * @throws IllegalStateException If a subclass calls this constructor.
   */
  public Textifier() {
    this(/* latest api = */ Opcodes.ASM9);
    if (getClass() != Textifier.class) {
      throw new IllegalStateException();
    }
  }

  /**
   * Constructs a new {@link Textifier}.
   *
   * @param api the ASM API version implemented by this visitor. Must be one of the {@code
   *     ASM}<i>x</i> values in {@link Opcodes}.
   */
  protected Textifier(final int api) {
    super(api);
  }

  /**
   * Prints a disassembled view of the given class to the standard output.
   *
   * <p>Usage: Textifier [-nodebug] &lt;binary class name or class file name &gt;
   *
   * @param args the command line arguments.
   * @throws IOException if the class cannot be found, or if an IOException occurs.
   */
  public static void main(final String[] args) throws IOException {
    main(args, new PrintWriter(System.out, true), new PrintWriter(System.err, true));
  }

  /**
   * Prints a disassembled view of the given class to the given output.
   *
   * <p>Usage: Textifier [-nodebug] &lt;binary class name or class file name &gt;
   *
   * @param args the command line arguments.
   * @param output where to print the result.
   * @param logger where to log errors.
   * @throws IOException if the class cannot be found, or if an IOException occurs.
   */
  static void main(final String[] args, final PrintWriter output, final PrintWriter logger)
      throws IOException {
    main(args, USAGE, new Textifier(), output, logger);
  }

  // -----------------------------------------------------------------------------------------------
  // Classes
  // -----------------------------------------------------------------------------------------------

  @Override
  public void visit(
      final int version,
      final int access,
      final String name,
      final String signature,
      final String superName,
      final String[] interfaces) {
    if ((access & Opcodes.ACC_MODULE) != 0) {
      // Modules are printed in visitModule.
      return;
    }
    this.access = access;
    int majorVersion = version & 0xFFFF;
    int minorVersion = version >>> 16;
    stringBuilder.setLength(0);
    stringBuilder
        .append("// class version ")
        .append(majorVersion)
        .append('.')
        .append(minorVersion)
        .append(" (")
        .append(version)
        .append(")\n");
    if ((access & Opcodes.ACC_DEPRECATED) != 0) {
      stringBuilder.append(DEPRECATED);
    }
    if ((access & Opcodes.ACC_RECORD) != 0) {
      stringBuilder.append(RECORD);
    }
    appendRawAccess(access);

    appendDescriptor(CLASS_SIGNATURE, signature);
    if (signature != null) {
      appendJavaDeclaration(name, signature);
    }

    appendAccess(access & ~(Opcodes.ACC_SUPER | Opcodes.ACC_MODULE));
    if ((access & Opcodes.ACC_ANNOTATION) != 0) {
      stringBuilder.append("@interface ");
    } else if ((access & Opcodes.ACC_INTERFACE) != 0) {
      stringBuilder.append("interface ");
    } else if ((access & Opcodes.ACC_ENUM) == 0) {
      stringBuilder.append("class ");
    }
    appendDescriptor(INTERNAL_NAME, name);

    if (superName != null && !"java/lang/Object".equals(superName)) {
      stringBuilder.append(" extends ");
      appendDescriptor(INTERNAL_NAME, superName);
    }
    if (interfaces != null && interfaces.length > 0) {
      stringBuilder.append(" implements ");
      for (int i = 0; i < interfaces.length; ++i) {
        appendDescriptor(INTERNAL_NAME, interfaces[i]);
        if (i != interfaces.length - 1) {
          stringBuilder.append(' ');
        }
      }
    }
    stringBuilder.append(" {\n\n");

    text.add(stringBuilder.toString());
  }

  @Override
  public void visitSource(final String file, final String debug) {
    stringBuilder.setLength(0);
    if (file != null) {
      stringBuilder.append(tab).append("// compiled from: ").append(file).append('\n');
    }
    if (debug != null) {
      stringBuilder.append(tab).append("// debug info: ").append(debug).append('\n');
    }
    if (stringBuilder.length() > 0) {
      text.add(stringBuilder.toString());
    }
  }

  @Override
  public Printer visitModule(final String name, final int access, final String version) {
    stringBuilder.setLength(0);
    if ((access & Opcodes.ACC_OPEN) != 0) {
      stringBuilder.append("open ");
    }
    stringBuilder
        .append("module ")
        .append(name)
        .append(" { ")
        .append(version == null ? "" : "// " + version)
        .append("\n\n");
    text.add(stringBuilder.toString());
    return addNewTextifier(null);
  }

  @Override
  public void visitNestHost(final String nestHost) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("NESTHOST ");
    appendDescriptor(INTERNAL_NAME, nestHost);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitOuterClass(final String owner, final String name, final String descriptor) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("OUTERCLASS ");
    appendDescriptor(INTERNAL_NAME, owner);
    stringBuilder.append(' ');
    if (name != null) {
      stringBuilder.append(name).append(' ');
    }
    appendDescriptor(METHOD_DESCRIPTOR, descriptor);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public Textifier visitClassAnnotation(final String descriptor, final boolean visible) {
    text.add("\n");
    return visitAnnotation(descriptor, visible);
  }

  @Override
  public Printer visitClassTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    text.add("\n");
    return visitTypeAnnotation(typeRef, typePath, descriptor, visible);
  }

  @Override
  public void visitClassAttribute(final Attribute attribute) {
    text.add("\n");
    visitAttribute(attribute);
  }

  @Override
  public void visitNestMember(final String nestMember) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("NESTMEMBER ");
    appendDescriptor(INTERNAL_NAME, nestMember);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitPermittedSubclass(final String permittedSubclass) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("PERMITTEDSUBCLASS ");
    appendDescriptor(INTERNAL_NAME, permittedSubclass);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitInnerClass(
      final String name, final String outerName, final String innerName, final int access) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab);
    appendRawAccess(access);
    stringBuilder.append(tab);
    appendAccess(access);
    stringBuilder.append("INNERCLASS ");
    appendDescriptor(INTERNAL_NAME, name);
    stringBuilder.append(' ');
    appendDescriptor(INTERNAL_NAME, outerName);
    stringBuilder.append(' ');
    appendDescriptor(INTERNAL_NAME, innerName);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public Printer visitRecordComponent(
      final String name, final String descriptor, final String signature) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("RECORDCOMPONENT ");
    if (signature != null) {
      stringBuilder.append(tab);
      appendDescriptor(FIELD_SIGNATURE, signature);
      stringBuilder.append(tab);
      appendJavaDeclaration(name, signature);
    }

    stringBuilder.append(tab);

    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append(' ').append(name);

    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
    return addNewTextifier(null);
  }

  @Override
  public Textifier visitField(
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final Object value) {
    stringBuilder.setLength(0);
    stringBuilder.append('\n');
    if ((access & Opcodes.ACC_DEPRECATED) != 0) {
      stringBuilder.append(tab).append(DEPRECATED);
    }
    stringBuilder.append(tab);
    appendRawAccess(access);
    if (signature != null) {
      stringBuilder.append(tab);
      appendDescriptor(FIELD_SIGNATURE, signature);
      stringBuilder.append(tab);
      appendJavaDeclaration(name, signature);
    }

    stringBuilder.append(tab);
    appendAccess(access);

    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append(' ').append(name);
    if (value != null) {
      stringBuilder.append(" = ");
      appendConstant(value);
    }

    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
    return addNewTextifier(null);
  }

  @Override
  public Textifier visitMethod(
      final int access,
      final String name,
      final String descriptor,
      final String signature,
      final String[] exceptions) {
    stringBuilder.setLength(0);
    stringBuilder.append('\n');
    if ((access & Opcodes.ACC_DEPRECATED) != 0) {
      stringBuilder.append(tab).append(DEPRECATED);
    }
    stringBuilder.append(tab);
    appendRawAccess(access);

    if (signature != null) {
      stringBuilder.append(tab);
      appendDescriptor(METHOD_SIGNATURE, signature);
      stringBuilder.append(tab);
      appendJavaDeclaration(name, signature);
    }

    stringBuilder.append(tab);
    appendAccess(access & ~(Opcodes.ACC_VOLATILE | Opcodes.ACC_TRANSIENT));
    if ((access & Opcodes.ACC_NATIVE) != 0) {
      stringBuilder.append("native ");
    }
    if ((access & Opcodes.ACC_VARARGS) != 0) {
      stringBuilder.append("varargs ");
    }
    if ((access & Opcodes.ACC_BRIDGE) != 0) {
      stringBuilder.append("bridge ");
    }
    if ((this.access & Opcodes.ACC_INTERFACE) != 0
        && (access & (Opcodes.ACC_ABSTRACT | Opcodes.ACC_STATIC)) == 0) {
      stringBuilder.append("default ");
    }

    stringBuilder.append(name);
    appendDescriptor(METHOD_DESCRIPTOR, descriptor);
    if (exceptions != null && exceptions.length > 0) {
      stringBuilder.append(" throws");
      for (String exception : exceptions) {
        stringBuilder.append(' ');
        appendDescriptor(INTERNAL_NAME, exception);
      }
    }

    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
    return addNewTextifier(null);
  }

  @Override
  public void visitClassEnd() {
    text.add("}\n");
  }

  // -----------------------------------------------------------------------------------------------
  // Modules
  // -----------------------------------------------------------------------------------------------

  @Override
  public void visitMainClass(final String mainClass) {
    stringBuilder.setLength(0);
    stringBuilder.append("  // main class ").append(mainClass).append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitPackage(final String packaze) {
    stringBuilder.setLength(0);
    stringBuilder.append("  // package ").append(packaze).append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitRequire(final String require, final int access, final String version) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("requires ");
    if ((access & Opcodes.ACC_TRANSITIVE) != 0) {
      stringBuilder.append("transitive ");
    }
    if ((access & Opcodes.ACC_STATIC_PHASE) != 0) {
      stringBuilder.append("static ");
    }
    stringBuilder.append(require).append(';');
    appendRawAccess(access);
    if (version != null) {
      stringBuilder.append("  // version ").append(version).append('\n');
    }
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitExport(final String packaze, final int access, final String... modules) {
    visitExportOrOpen("exports ", packaze, access, modules);
  }

  @Override
  public void visitOpen(final String packaze, final int access, final String... modules) {
    visitExportOrOpen("opens ", packaze, access, modules);
  }

  private void visitExportOrOpen(
      final String method, final String packaze, final int access, final String... modules) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append(method);
    stringBuilder.append(packaze);
    if (modules != null && modules.length > 0) {
      stringBuilder.append(" to");
    } else {
      stringBuilder.append(';');
    }
    appendRawAccess(access);
    if (modules != null && modules.length > 0) {
      for (int i = 0; i < modules.length; ++i) {
        stringBuilder.append(tab2).append(modules[i]);
        stringBuilder.append(i != modules.length - 1 ? ",\n" : ";\n");
      }
    }
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitUse(final String use) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("uses ");
    appendDescriptor(INTERNAL_NAME, use);
    stringBuilder.append(";\n");
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitProvide(final String provide, final String... providers) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("provides ");
    appendDescriptor(INTERNAL_NAME, provide);
    stringBuilder.append(" with\n");
    for (int i = 0; i < providers.length; ++i) {
      stringBuilder.append(tab2);
      appendDescriptor(INTERNAL_NAME, providers[i]);
      stringBuilder.append(i != providers.length - 1 ? ",\n" : ";\n");
    }
    text.add(stringBuilder.toString());
  }

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

  // -----------------------------------------------------------------------------------------------
  // Annotations
  // -----------------------------------------------------------------------------------------------

  // DontCheck(OverloadMethodsDeclarationOrder): overloads are semantically different.
  @Override
  public void visit(final String name, final Object value) {
    visitAnnotationValue(name);
    if (value instanceof String) {
      visitString((String) value);
    } else if (value instanceof Type) {
      visitType((Type) value);
    } else if (value instanceof Byte) {
      visitByte(((Byte) value).byteValue());
    } else if (value instanceof Boolean) {
      visitBoolean(((Boolean) value).booleanValue());
    } else if (value instanceof Short) {
      visitShort(((Short) value).shortValue());
    } else if (value instanceof Character) {
      visitChar(((Character) value).charValue());
    } else if (value instanceof Integer) {
      visitInt(((Integer) value).intValue());
    } else if (value instanceof Float) {
      visitFloat(((Float) value).floatValue());
    } else if (value instanceof Long) {
      visitLong(((Long) value).longValue());
    } else if (value instanceof Double) {
      visitDouble(((Double) value).doubleValue());
    } else if (value.getClass().isArray()) {
      stringBuilder.append('{');
      if (value instanceof byte[]) {
        byte[] byteArray = (byte[]) value;
        for (int i = 0; i < byteArray.length; i++) {
          maybeAppendComma(i);
          visitByte(byteArray[i]);
        }
      } else if (value instanceof boolean[]) {
        boolean[] booleanArray = (boolean[]) value;
        for (int i = 0; i < booleanArray.length; i++) {
          maybeAppendComma(i);
          visitBoolean(booleanArray[i]);
        }
      } else if (value instanceof short[]) {
        short[] shortArray = (short[]) value;
        for (int i = 0; i < shortArray.length; i++) {
          maybeAppendComma(i);
          visitShort(shortArray[i]);
        }
      } else if (value instanceof char[]) {
        char[] charArray = (char[]) value;
        for (int i = 0; i < charArray.length; i++) {
          maybeAppendComma(i);
          visitChar(charArray[i]);
        }
      } else if (value instanceof int[]) {
        int[] intArray = (int[]) value;
        for (int i = 0; i < intArray.length; i++) {
          maybeAppendComma(i);
          visitInt(intArray[i]);
        }
      } else if (value instanceof long[]) {
        long[] longArray = (long[]) value;
        for (int i = 0; i < longArray.length; i++) {
          maybeAppendComma(i);
          visitLong(longArray[i]);
        }
      } else if (value instanceof float[]) {
        float[] floatArray = (float[]) value;
        for (int i = 0; i < floatArray.length; i++) {
          maybeAppendComma(i);
          visitFloat(floatArray[i]);
        }
      } else if (value instanceof double[]) {
        double[] doubleArray = (double[]) value;
        for (int i = 0; i < doubleArray.length; i++) {
          maybeAppendComma(i);
          visitDouble(doubleArray[i]);
        }
      }
      stringBuilder.append('}');
    }
    text.add(stringBuilder.toString());
  }

  private void visitInt(final int value) {
    stringBuilder.append(value);
  }

  private void visitLong(final long value) {
    stringBuilder.append(value).append('L');
  }

  private void visitFloat(final float value) {
    stringBuilder.append(value).append('F');
  }

  private void visitDouble(final double value) {
    stringBuilder.append(value).append('D');
  }

  private void visitChar(final char value) {
    stringBuilder.append("(char)").append((int) value);
  }

  private void visitShort(final short value) {
    stringBuilder.append("(short)").append(value);
  }

  private void visitByte(final byte value) {
    stringBuilder.append("(byte)").append(value);
  }

  private void visitBoolean(final boolean value) {
    stringBuilder.append(value);
  }

  private void visitString(final String value) {
    appendString(stringBuilder, value);
  }

  private void visitType(final Type value) {
    stringBuilder.append(value.getClassName()).append(CLASS_SUFFIX);
  }

  @Override
  public void visitEnum(final String name, final String descriptor, final String value) {
    visitAnnotationValue(name);
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('.').append(value);
    text.add(stringBuilder.toString());
  }

  @Override
  public Textifier visitAnnotation(final String name, final String descriptor) {
    visitAnnotationValue(name);
    stringBuilder.append('@');
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('(');
    text.add(stringBuilder.toString());
    return addNewTextifier(")");
  }

  @Override
  public Textifier visitArray(final String name) {
    visitAnnotationValue(name);
    stringBuilder.append('{');
    text.add(stringBuilder.toString());
    return addNewTextifier("}");
  }

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

  private void visitAnnotationValue(final String name) {
    stringBuilder.setLength(0);
    maybeAppendComma(numAnnotationValues++);
    if (name != null) {
      stringBuilder.append(name).append('=');
    }
  }

  // -----------------------------------------------------------------------------------------------
  // Record components
  // -----------------------------------------------------------------------------------------------

  @Override
  public Textifier visitRecordComponentAnnotation(final String descriptor, final boolean visible) {
    return visitAnnotation(descriptor, visible);
  }

  @Override
  public Printer visitRecordComponentTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    return visitTypeAnnotation(typeRef, typePath, descriptor, visible);
  }

  @Override
  public void visitRecordComponentAttribute(final Attribute attribute) {
    visitAttribute(attribute);
  }

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

  // -----------------------------------------------------------------------------------------------
  // Fields
  // -----------------------------------------------------------------------------------------------

  @Override
  public Textifier visitFieldAnnotation(final String descriptor, final boolean visible) {
    return visitAnnotation(descriptor, visible);
  }

  @Override
  public Printer visitFieldTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    return visitTypeAnnotation(typeRef, typePath, descriptor, visible);
  }

  @Override
  public void visitFieldAttribute(final Attribute attribute) {
    visitAttribute(attribute);
  }

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

  // -----------------------------------------------------------------------------------------------
  // Methods
  // -----------------------------------------------------------------------------------------------

  @Override
  public void visitParameter(final String name, final int access) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("// parameter ");
    appendAccess(access);
    stringBuilder.append(' ').append((name == null) ? "<no name>" : name).append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public Textifier visitAnnotationDefault() {
    text.add(tab2 + "default=");
    return addNewTextifier("\n");
  }

  @Override
  public Textifier visitMethodAnnotation(final String descriptor, final boolean visible) {
    return visitAnnotation(descriptor, visible);
  }

  @Override
  public Printer visitMethodTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    return visitTypeAnnotation(typeRef, typePath, descriptor, visible);
  }

  @Override
  public Textifier visitAnnotableParameterCount(final int parameterCount, final boolean visible) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("// annotable parameter count: ");
    stringBuilder.append(parameterCount);
    stringBuilder.append(visible ? " (visible)\n" : " (invisible)\n");
    text.add(stringBuilder.toString());
    return this;
  }

  @Override
  public Textifier visitParameterAnnotation(
      final int parameter, final String descriptor, final boolean visible) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append('@');
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('(');
    text.add(stringBuilder.toString());

    stringBuilder.setLength(0);
    stringBuilder
        .append(visible ? ") // parameter " : ") // invisible, parameter ")
        .append(parameter)
        .append('\n');
    return addNewTextifier(stringBuilder.toString());
  }

  @Override
  public void visitMethodAttribute(final Attribute attribute) {
    visitAttribute(attribute);
  }

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

  @Override
  public void visitFrame(
      final int type,
      final int numLocal,
      final Object[] local,
      final int numStack,
      final Object[] stack) {
    stringBuilder.setLength(0);
    stringBuilder.append(ltab);
    stringBuilder.append("FRAME ");
    switch (type) {
      case Opcodes.F_NEW:
      case Opcodes.F_FULL:
        stringBuilder.append("FULL [");
        appendFrameTypes(numLocal, local);
        stringBuilder.append("] [");
        appendFrameTypes(numStack, stack);
        stringBuilder.append(']');
        break;
      case Opcodes.F_APPEND:
        stringBuilder.append("APPEND [");
        appendFrameTypes(numLocal, local);
        stringBuilder.append(']');
        break;
      case Opcodes.F_CHOP:
        stringBuilder.append("CHOP ").append(numLocal);
        break;
      case Opcodes.F_SAME:
        stringBuilder.append("SAME");
        break;
      case Opcodes.F_SAME1:
        stringBuilder.append("SAME1 ");
        appendFrameTypes(1, stack);
        break;
      default:
        throw new IllegalArgumentException();
    }
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitInsn(final int opcode) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append(OPCODES[opcode]).append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitIntInsn(final int opcode, final int operand) {
    stringBuilder.setLength(0);
    stringBuilder
        .append(tab2)
        .append(OPCODES[opcode])
        .append(' ')
        .append(opcode == Opcodes.NEWARRAY ? TYPES[operand] : Integer.toString(operand))
        .append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitVarInsn(final int opcode, final int varIndex) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append(OPCODES[opcode]).append(' ').append(varIndex).append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitTypeInsn(final int opcode, final String type) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append(OPCODES[opcode]).append(' ');
    appendDescriptor(INTERNAL_NAME, type);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitFieldInsn(
      final int opcode, final String owner, final String name, final String descriptor) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append(OPCODES[opcode]).append(' ');
    appendDescriptor(INTERNAL_NAME, owner);
    stringBuilder.append('.').append(name).append(" : ");
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitMethodInsn(
      final int opcode,
      final String owner,
      final String name,
      final String descriptor,
      final boolean isInterface) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append(OPCODES[opcode]).append(' ');
    appendDescriptor(INTERNAL_NAME, owner);
    stringBuilder.append('.').append(name).append(' ');
    appendDescriptor(METHOD_DESCRIPTOR, descriptor);
    if (isInterface) {
      stringBuilder.append(" (itf)");
    }
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitInvokeDynamicInsn(
      final String name,
      final String descriptor,
      final Handle bootstrapMethodHandle,
      final Object... bootstrapMethodArguments) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("INVOKEDYNAMIC").append(' ');
    stringBuilder.append(name);
    appendDescriptor(METHOD_DESCRIPTOR, descriptor);
    stringBuilder.append(" [");
    stringBuilder.append('\n');
    stringBuilder.append(tab3);
    appendHandle(bootstrapMethodHandle, tab3);
    stringBuilder.append('\n').append(tab3);
    appendBoostrapMethodArgs(bootstrapMethodArguments, tab3);
    stringBuilder.append('\n');
    stringBuilder.append(tab2).append("]\n");
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitJumpInsn(final int opcode, final Label label) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append(OPCODES[opcode]).append(' ');
    appendLabel(label);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitLabel(final Label label) {
    stringBuilder.setLength(0);
    stringBuilder.append(ltab);
    appendLabel(label);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitLdcInsn(final Object value) {
    stringBuilder.setLength(0);
    if (value instanceof ConstantDynamic) {
      stringBuilder.append(tab2).append("LDC ");
      appendConstantDynamic((ConstantDynamic) value, tab2);
    } else if (value instanceof Handle) {
      stringBuilder.append(tab2);
      appendHandle((Handle) value, tab2 + "LDC ");
    } else {
      stringBuilder.append(tab2).append("LDC ");
      appendConstant(value);
    }
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitIincInsn(final int varIndex, final int increment) {
    stringBuilder.setLength(0);
    stringBuilder
        .append(tab2)
        .append("IINC ")
        .append(varIndex)
        .append(' ')
        .append(increment)
        .append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitTableSwitchInsn(
      final int min, final int max, final Label dflt, final Label... labels) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("TABLESWITCH\n");
    for (int i = 0; i < labels.length; ++i) {
      stringBuilder.append(tab3).append(min + i).append(": ");
      appendLabel(labels[i]);
      stringBuilder.append('\n');
    }
    stringBuilder.append(tab3).append("default: ");
    appendLabel(dflt);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitLookupSwitchInsn(final Label dflt, final int[] keys, final Label[] labels) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("LOOKUPSWITCH\n");
    for (int i = 0; i < labels.length; ++i) {
      stringBuilder.append(tab3).append(keys[i]).append(": ");
      appendLabel(labels[i]);
      stringBuilder.append('\n');
    }
    stringBuilder.append(tab3).append("default: ");
    appendLabel(dflt);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitMultiANewArrayInsn(final String descriptor, final int numDimensions) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("MULTIANEWARRAY ");
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append(' ').append(numDimensions).append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public Printer visitInsnAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    return visitTypeAnnotation(typeRef, typePath, descriptor, visible);
  }

  @Override
  public void visitTryCatchBlock(
      final Label start, final Label end, final Label handler, final String type) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("TRYCATCHBLOCK ");
    appendLabel(start);
    stringBuilder.append(' ');
    appendLabel(end);
    stringBuilder.append(' ');
    appendLabel(handler);
    stringBuilder.append(' ');
    appendDescriptor(INTERNAL_NAME, type);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public Printer visitTryCatchAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("TRYCATCHBLOCK @");
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('(');
    text.add(stringBuilder.toString());

    stringBuilder.setLength(0);
    stringBuilder.append(") : ");
    appendTypeReference(typeRef);
    stringBuilder.append(", ").append(typePath);
    stringBuilder.append(visible ? "\n" : INVISIBLE);
    return addNewTextifier(stringBuilder.toString());
  }

  @Override
  public void visitLocalVariable(
      final String name,
      final String descriptor,
      final String signature,
      final Label start,
      final Label end,
      final int index) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("LOCALVARIABLE ").append(name).append(' ');
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append(' ');
    appendLabel(start);
    stringBuilder.append(' ');
    appendLabel(end);
    stringBuilder.append(' ').append(index).append('\n');

    if (signature != null) {
      stringBuilder.append(tab2);
      appendDescriptor(FIELD_SIGNATURE, signature);
      stringBuilder.append(tab2);
      appendJavaDeclaration(name, signature);
    }
    text.add(stringBuilder.toString());
  }

  @Override
  public Printer visitLocalVariableAnnotation(
      final int typeRef,
      final TypePath typePath,
      final Label[] start,
      final Label[] end,
      final int[] index,
      final String descriptor,
      final boolean visible) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("LOCALVARIABLE @");
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('(');
    text.add(stringBuilder.toString());

    stringBuilder.setLength(0);
    stringBuilder.append(") : ");
    appendTypeReference(typeRef);
    stringBuilder.append(", ").append(typePath);
    for (int i = 0; i < start.length; ++i) {
      stringBuilder.append(" [ ");
      appendLabel(start[i]);
      stringBuilder.append(" - ");
      appendLabel(end[i]);
      stringBuilder.append(" - ").append(index[i]).append(" ]");
    }
    stringBuilder.append(visible ? "\n" : INVISIBLE);
    return addNewTextifier(stringBuilder.toString());
  }

  @Override
  public void visitLineNumber(final int line, final Label start) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("LINENUMBER ").append(line).append(' ');
    appendLabel(start);
    stringBuilder.append('\n');
    text.add(stringBuilder.toString());
  }

  @Override
  public void visitMaxs(final int maxStack, final int maxLocals) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("MAXSTACK = ").append(maxStack).append('\n');
    text.add(stringBuilder.toString());

    stringBuilder.setLength(0);
    stringBuilder.append(tab2).append("MAXLOCALS = ").append(maxLocals).append('\n');
    text.add(stringBuilder.toString());
  }

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

  // -----------------------------------------------------------------------------------------------
  // Common methods
  // -----------------------------------------------------------------------------------------------

  /**
   * Prints a disassembled view of the given annotation.
   *
   * @param descriptor the class descriptor of the annotation class.
   * @param visible {@literal true} if the annotation is visible at runtime.
   * @return a visitor to visit the annotation values.
   */
  // DontCheck(OverloadMethodsDeclarationOrder): overloads are semantically different.
  public Textifier visitAnnotation(final String descriptor, final boolean visible) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append('@');
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('(');
    text.add(stringBuilder.toString());
    return addNewTextifier(visible ? ")\n" : ") // invisible\n");
  }

  /**
   * Prints a disassembled view of the given type annotation.
   *
   * @param typeRef a reference to the annotated type. See {@link TypeReference}.
   * @param typePath the path to the annotated type argument, wildcard bound, array element type, or
   *     static inner type within 'typeRef'. May be {@literal null} if the annotation targets
   *     'typeRef' as a whole.
   * @param descriptor the class descriptor of the annotation class.
   * @param visible {@literal true} if the annotation is visible at runtime.
   * @return a visitor to visit the annotation values.
   */
  public Textifier visitTypeAnnotation(
      final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append('@');
    appendDescriptor(FIELD_DESCRIPTOR, descriptor);
    stringBuilder.append('(');
    text.add(stringBuilder.toString());

    stringBuilder.setLength(0);
    stringBuilder.append(") : ");
    appendTypeReference(typeRef);
    stringBuilder.append(", ").append(typePath);
    stringBuilder.append(visible ? "\n" : INVISIBLE);
    return addNewTextifier(stringBuilder.toString());
  }

  /**
   * Prints a disassembled view of the given attribute.
   *
   * @param attribute an attribute.
   */
  public void visitAttribute(final Attribute attribute) {
    stringBuilder.setLength(0);
    stringBuilder.append(tab).append("ATTRIBUTE ");
    appendDescriptor(-1, attribute.type);

    if (attribute instanceof TextifierSupport) {
      if (labelNames == null) {
        labelNames = new HashMap<>();
      }
      ((TextifierSupport) attribute).textify(stringBuilder, labelNames);
    } else {
      stringBuilder.append(" : unknown\n");
    }

    text.add(stringBuilder.toString());
  }

  // -----------------------------------------------------------------------------------------------
  // Utility methods
  // -----------------------------------------------------------------------------------------------

  /**
   * Appends a string representation of the given access flags to {@link #stringBuilder}.
   *
   * @param accessFlags some access flags.
   */
  private void appendAccess(final int accessFlags) {
    if ((accessFlags & Opcodes.ACC_PUBLIC) != 0) {
      stringBuilder.append("public ");
    }
    if ((accessFlags & Opcodes.ACC_PRIVATE) != 0) {
      stringBuilder.append("private ");
    }
    if ((accessFlags & Opcodes.ACC_PROTECTED) != 0) {
      stringBuilder.append("protected ");
    }
    if ((accessFlags & Opcodes.ACC_FINAL) != 0) {
      stringBuilder.append("final ");
    }
    if ((accessFlags & Opcodes.ACC_STATIC) != 0) {
      stringBuilder.append("static ");
    }
    if ((accessFlags & Opcodes.ACC_SYNCHRONIZED) != 0) {
      stringBuilder.append("synchronized ");
    }
    if ((accessFlags & Opcodes.ACC_VOLATILE) != 0) {
      stringBuilder.append("volatile ");
    }
    if ((accessFlags & Opcodes.ACC_TRANSIENT) != 0) {
      stringBuilder.append("transient ");
    }
    if ((accessFlags & Opcodes.ACC_ABSTRACT) != 0) {
      stringBuilder.append("abstract ");
    }
    if ((accessFlags & Opcodes.ACC_STRICT) != 0) {
      stringBuilder.append("strictfp ");
    }
    if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0) {
      stringBuilder.append("synthetic ");
    }
    if ((accessFlags & Opcodes.ACC_MANDATED) != 0) {
      stringBuilder.append("mandated ");
    }
    if ((accessFlags & Opcodes.ACC_ENUM) != 0) {
      stringBuilder.append("enum ");
    }
  }

  /**
   * Appends a constant value. This method can be used for {@link Integer}, {@link Float}, {@link
   * Long}, {@link Double}, {@link Boolean}, {@link String}, and {@link Type}. Attempting to use any
   * other type will result in its {@link Object#toString()} representation.
   *
   * @param constant the constant to be appended.
   */
  private void appendConstant(final Object constant) {
    if (constant instanceof Number) {
      if (constant instanceof Double) {
        stringBuilder.append(constant).append('D');
      } else if (constant instanceof Float) {
        stringBuilder.append(constant).append('F');
      } else if (constant instanceof Long) {
        stringBuilder.append(constant).append('L');
      } else {
        // Integer (or other "unsupported" Number subclass)
        stringBuilder.append(constant);
      }
    } else {
      if (constant instanceof Type) {
        stringBuilder.append(((Type) constant).getDescriptor()).append(CLASS_SUFFIX);
      } else if (constant instanceof String) {
        Printer.appendString(stringBuilder, constant.toString());
      } else {
        // Boolean or other "unsupported" constant
        stringBuilder.append(constant);
      }
    }
  }

  /**
   * Append the contents of a {@link ConstantDynamic}.
   *
   * @param condy the constant dynamic to append
   * @param condyIndent the indent to use for newlines.
   */
  private void appendConstantDynamic(final ConstantDynamic condy, final String condyIndent) {
    stringBuilder
        .append(condy.getName())
        .append(" : ")
        .append(condy.getDescriptor())
        .append(" [\n");
    stringBuilder.append(condyIndent).append(tab);
    appendHandle(condy.getBootstrapMethod(), condyIndent + tab);
    stringBuilder.append('\n').append(condyIndent).append(tab);
    Object[] bsmArgs = new Object[condy.getBootstrapMethodArgumentCount()];
    for (int i = 0; i < bsmArgs.length; i++) {
      bsmArgs[i] = condy.getBootstrapMethodArgument(i);
    }
    appendBoostrapMethodArgs(bsmArgs, condyIndent + tab);
    stringBuilder.append('\n').append(condyIndent).append(']');
  }

  /**
   * Appends bootstrap method args for {@link ConstantDynamic} and {@link #visitInvokeDynamicInsn}.
   *
   * @param bsmArgs the bootstrap method arguments.
   * @param argIndent the indent to use for newlines.
   */
  private void appendBoostrapMethodArgs(final Object[] bsmArgs, final String argIndent) {
    stringBuilder.append("// arguments:");
    if (bsmArgs.length == 0) {
      stringBuilder.append(" none");
    } else {
      for (int i = 0; i < bsmArgs.length; i++) {
        Object arg = bsmArgs[i];
        if (i != 0) {
          stringBuilder.append(", ");
        }
        stringBuilder.append('\n').append(argIndent);
        if (arg instanceof Type) {
          Type type = (Type) arg;
          if (type.getSort() == Type.METHOD) {
            appendDescriptor(METHOD_DESCRIPTOR, type.getDescriptor());
          } else {
            visitType(type);
          }
        } else if (arg instanceof Handle) {
          appendHandle((Handle) arg, argIndent);
        } else if (arg instanceof ConstantDynamic) {
          stringBuilder.append("// constant dynamic: ").append('\n').append(argIndent);
          appendConstantDynamic((ConstantDynamic) arg, argIndent);
        } else {
          appendConstant(arg);
        }
      }
    }
  }

  /**
   * Appends the hexadecimal value of the given access flags to {@link #stringBuilder}.
   *
   * @param accessFlags some access flags.
   */
  private void appendRawAccess(final int accessFlags) {
    stringBuilder
        .append("// access flags 0x")
        .append(Integer.toHexString(accessFlags).toUpperCase())
        .append('\n');
  }

  /**
   * Appends an internal name, a type descriptor or a type signature to {@link #stringBuilder}.
   *
   * @param type the type of 'value'. Must be one of {@link #INTERNAL_NAME}, {@link
   *     #FIELD_DESCRIPTOR}, {@link #FIELD_SIGNATURE}, {@link #METHOD_DESCRIPTOR}, {@link
   *     #METHOD_SIGNATURE}, {@link #CLASS_SIGNATURE} or {@link #HANDLE_DESCRIPTOR}.
   * @param value an internal name (see {@link Type#getInternalName()}), type descriptor or a type
   *     signature. May be {@literal null}.
   */
  protected void appendDescriptor(final int type, final String value) {
    if (type == CLASS_SIGNATURE || type == FIELD_SIGNATURE || type == METHOD_SIGNATURE) {
      if (value != null) {
        stringBuilder.append("// signature ").append(value).append('\n');
      }
    } else {
      stringBuilder.append(value);
    }
  }

  /**
   * Appends the Java generic type declaration corresponding to the given signature.
   *
   * @param name a class, field or method name.
   * @param signature a class, field or method signature.
   */
  private void appendJavaDeclaration(final String name, final String signature) {
    TraceSignatureVisitor traceSignatureVisitor = new TraceSignatureVisitor(access);
    new SignatureReader(signature).accept(traceSignatureVisitor);
    stringBuilder.append("// declaration: ");
    if (traceSignatureVisitor.getReturnType() != null) {
      stringBuilder.append(traceSignatureVisitor.getReturnType());
      stringBuilder.append(' ');
    }
    stringBuilder.append(name);
    stringBuilder.append(traceSignatureVisitor.getDeclaration());
    if (traceSignatureVisitor.getExceptions() != null) {
      stringBuilder.append(" throws ").append(traceSignatureVisitor.getExceptions());
    }
    stringBuilder.append('\n');
  }

  /**
   * Appends the name of the given label to {@link #stringBuilder}. Constructs a new label name if
   * the given label does not yet have one.
   *
   * @param label a label.
   */
  protected void appendLabel(final Label label) {
    if (labelNames == null) {
      labelNames = new HashMap<>();
    }
    String name = labelNames.get(label);
    if (name == null) {
      name = "L" + labelNames.size();
      labelNames.put(label, name);
    }
    stringBuilder.append(name);
  }

  @Deprecated
  protected void appendHandle(final Handle handle) {
    appendHandle(handle, tab3);
  }

  /**
   * Appends a string representation of the given handle to {@link #stringBuilder}.
   *
   * @param handle a handle.
   * @param afterComment this is the prefix of the line after the handle kind.
   */
  protected void appendHandle(final Handle handle, final String afterComment) {
    int tag = handle.getTag();
    stringBuilder.append("// handle kind 0x").append(Integer.toHexString(tag)).append(" : ");
    boolean isMethodHandle = false;
    switch (tag) {
      case Opcodes.H_GETFIELD:
        stringBuilder.append("GETFIELD");
        break;
      case Opcodes.H_GETSTATIC:
        stringBuilder.append("GETSTATIC");
        break;
      case Opcodes.H_PUTFIELD:
        stringBuilder.append("PUTFIELD");
        break;
      case Opcodes.H_PUTSTATIC:
        stringBuilder.append("PUTSTATIC");
        break;
      case Opcodes.H_INVOKEINTERFACE:
        stringBuilder.append("INVOKEINTERFACE");
        isMethodHandle = true;
        break;
      case Opcodes.H_INVOKESPECIAL:
        stringBuilder.append("INVOKESPECIAL");
        isMethodHandle = true;
        break;
      case Opcodes.H_INVOKESTATIC:
        stringBuilder.append("INVOKESTATIC");
        isMethodHandle = true;
        break;
      case Opcodes.H_INVOKEVIRTUAL:
        stringBuilder.append("INVOKEVIRTUAL");
        isMethodHandle = true;
        break;
      case Opcodes.H_NEWINVOKESPECIAL:
        stringBuilder.append("NEWINVOKESPECIAL");
        isMethodHandle = true;
        break;
      default:
        throw new IllegalArgumentException();
    }
    stringBuilder.append('\n');
    stringBuilder.append(afterComment);
    appendDescriptor(INTERNAL_NAME, handle.getOwner());
    stringBuilder.append('.');
    stringBuilder.append(handle.getName());
    if (!isMethodHandle) {
      stringBuilder.append('(');
    }
    appendDescriptor(HANDLE_DESCRIPTOR, handle.getDesc());
    if (!isMethodHandle) {
      stringBuilder.append(')');
    }
    if (handle.isInterface()) {
      stringBuilder.append(" itf");
    }
  }

  /**
   * Appends a comma to {@link #stringBuilder} if the given number is strictly positive.
   *
   * @param numValues a number of 'values visited so far', for instance the number of annotation
   *     values visited so far in an annotation visitor.
   */
  private void maybeAppendComma(final int numValues) {
    if (numValues > 0) {
      stringBuilder.append(", ");
    }
  }

  /**
   * Appends a string representation of the given type reference to {@link #stringBuilder}.
   *
   * @param typeRef a type reference. See {@link TypeReference}.
   */
  private void appendTypeReference(final int typeRef) {
    TypeReference typeReference = new TypeReference(typeRef);
    switch (typeReference.getSort()) {
      case TypeReference.CLASS_TYPE_PARAMETER:
        stringBuilder.append("CLASS_TYPE_PARAMETER ").append(typeReference.getTypeParameterIndex());
        break;
      case TypeReference.METHOD_TYPE_PARAMETER:
        stringBuilder
            .append("METHOD_TYPE_PARAMETER ")
            .append(typeReference.getTypeParameterIndex());
        break;
      case TypeReference.CLASS_EXTENDS:
        stringBuilder.append("CLASS_EXTENDS ").append(typeReference.getSuperTypeIndex());
        break;
      case TypeReference.CLASS_TYPE_PARAMETER_BOUND:
        stringBuilder
            .append("CLASS_TYPE_PARAMETER_BOUND ")
            .append(typeReference.getTypeParameterIndex())
            .append(", ")
            .append(typeReference.getTypeParameterBoundIndex());
        break;
      case TypeReference.METHOD_TYPE_PARAMETER_BOUND:
        stringBuilder
            .append("METHOD_TYPE_PARAMETER_BOUND ")
            .append(typeReference.getTypeParameterIndex())
            .append(", ")
            .append(typeReference.getTypeParameterBoundIndex());
        break;
      case TypeReference.FIELD:
        stringBuilder.append("FIELD");
        break;
      case TypeReference.METHOD_RETURN:
        stringBuilder.append("METHOD_RETURN");
        break;
      case TypeReference.METHOD_RECEIVER:
        stringBuilder.append("METHOD_RECEIVER");
        break;
      case TypeReference.METHOD_FORMAL_PARAMETER:
        stringBuilder
            .append("METHOD_FORMAL_PARAMETER ")
            .append(typeReference.getFormalParameterIndex());
        break;
      case TypeReference.THROWS:
        stringBuilder.append("THROWS ").append(typeReference.getExceptionIndex());
        break;
      case TypeReference.LOCAL_VARIABLE:
        stringBuilder.append("LOCAL_VARIABLE");
        break;
      case TypeReference.RESOURCE_VARIABLE:
        stringBuilder.append("RESOURCE_VARIABLE");
        break;
      case TypeReference.EXCEPTION_PARAMETER:
        stringBuilder.append("EXCEPTION_PARAMETER ").append(typeReference.getTryCatchBlockIndex());
        break;
      case TypeReference.INSTANCEOF:
        stringBuilder.append("INSTANCEOF");
        break;
      case TypeReference.NEW:
        stringBuilder.append("NEW");
        break;
      case TypeReference.CONSTRUCTOR_REFERENCE:
        stringBuilder.append("CONSTRUCTOR_REFERENCE");
        break;
      case TypeReference.METHOD_REFERENCE:
        stringBuilder.append("METHOD_REFERENCE");
        break;
      case TypeReference.CAST:
        stringBuilder.append("CAST ").append(typeReference.getTypeArgumentIndex());
        break;
      case TypeReference.CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT:
        stringBuilder
            .append("CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT ")
            .append(typeReference.getTypeArgumentIndex());
        break;
      case TypeReference.METHOD_INVOCATION_TYPE_ARGUMENT:
        stringBuilder
            .append("METHOD_INVOCATION_TYPE_ARGUMENT ")
            .append(typeReference.getTypeArgumentIndex());
        break;
      case TypeReference.CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT:
        stringBuilder
            .append("CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT ")
            .append(typeReference.getTypeArgumentIndex());
        break;
      case TypeReference.METHOD_REFERENCE_TYPE_ARGUMENT:
        stringBuilder
            .append("METHOD_REFERENCE_TYPE_ARGUMENT ")
            .append(typeReference.getTypeArgumentIndex());
        break;
      default:
        throw new IllegalArgumentException();
    }
  }

  /**
   * Appends the given stack map frame types to {@link #stringBuilder}.
   *
   * @param numTypes the number of stack map frame types in 'frameTypes'.
   * @param frameTypes an array of stack map frame types, in the format described in {@link
   *     scala.tools.asm.MethodVisitor#visitFrame}.
   */
  private void appendFrameTypes(final int numTypes, final Object[] frameTypes) {
    for (int i = 0; i < numTypes; ++i) {
      if (i > 0) {
        stringBuilder.append(' ');
      }
      if (frameTypes[i] instanceof String) {
        String descriptor = (String) frameTypes[i];
        if (descriptor.charAt(0) == '[') {
          appendDescriptor(FIELD_DESCRIPTOR, descriptor);
        } else {
          appendDescriptor(INTERNAL_NAME, descriptor);
        }
      } else if (frameTypes[i] instanceof Integer) {
        stringBuilder.append(FRAME_TYPES.get(((Integer) frameTypes[i]).intValue()));
      } else {
        appendLabel((Label) frameTypes[i]);
      }
    }
  }

  /**
   * Creates and adds to {@link #text} a new {@link Textifier}, followed by the given string.
   *
   * @param endText the text to add to {@link #text} after the textifier. May be {@literal null}.
   * @return the newly created {@link Textifier}.
   */
  private Textifier addNewTextifier(final String endText) {
    Textifier textifier = createTextifier();
    text.add(textifier.getText());
    if (endText != null) {
      text.add(endText);
    }
    return textifier;
  }

  /**
   * Creates a new {@link Textifier}.
   *
   * @return a new {@link Textifier}.
   */
  protected Textifier createTextifier() {
    return new Textifier(api);
  }
}
