plastic/src/external/java/org/apache/tapestry5/internal/plastic/asm/util/CheckAnnotationAdapter.java

// 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
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package org.apache.tapestry5.internal.plastic.asm.util;

import org.apache.tapestry5.internal.plastic.asm.AnnotationVisitor;
import org.apache.tapestry5.internal.plastic.asm.Opcodes;
import org.apache.tapestry5.internal.plastic.asm.Type;

/**
 * An {@link AnnotationVisitor} that checks that its methods are properly used.
 *
 * @author Eric Bruneton
 */
public class CheckAnnotationAdapter extends AnnotationVisitor {

  /**
   * Whether the values of the visited annotation are named. AnnotationVisitor instances used for
   * annotation default and annotation arrays use unnamed values.
   */
  private final boolean useNamedValue;

  /** Whether the {@link #visitEnd} method has been called. */
  private boolean visitEndCalled;

  public CheckAnnotationAdapter(final AnnotationVisitor annotationVisitor) {
    this(annotationVisitor, true);
  }

  CheckAnnotationAdapter(final AnnotationVisitor annotationVisitor, final boolean useNamedValues) {
    super(/* latest api = */ Opcodes.ASM8, annotationVisitor);
    this.useNamedValue = useNamedValues;
  }

  @Override
  public void visit(final String name, final Object value) {
    checkVisitEndNotCalled();
    checkName(name);
    if (!(value instanceof Byte
        || value instanceof Boolean
        || value instanceof Character
        || value instanceof Short
        || value instanceof Integer
        || value instanceof Long
        || value instanceof Float
        || value instanceof Double
        || value instanceof String
        || value instanceof Type
        || value instanceof byte[]
        || value instanceof boolean[]
        || value instanceof char[]
        || value instanceof short[]
        || value instanceof int[]
        || value instanceof long[]
        || value instanceof float[]
        || value instanceof double[])) {
      throw new IllegalArgumentException("Invalid annotation value");
    }
    if (value instanceof Type && ((Type) value).getSort() == Type.METHOD) {
      throw new IllegalArgumentException("Invalid annotation value");
    }
    super.visit(name, value);
  }

  @Override
  public void visitEnum(final String name, final String descriptor, final String value) {
    checkVisitEndNotCalled();
    checkName(name);
    // Annotations can only appear in V1_5 or more classes.
    CheckMethodAdapter.checkDescriptor(Opcodes.V1_5, descriptor, false);
    if (value == null) {
      throw new IllegalArgumentException("Invalid enum value");
    }
    super.visitEnum(name, descriptor, value);
  }

  @Override
  public AnnotationVisitor visitAnnotation(final String name, final String descriptor) {
    checkVisitEndNotCalled();
    checkName(name);
    // Annotations can only appear in V1_5 or more classes.
    CheckMethodAdapter.checkDescriptor(Opcodes.V1_5, descriptor, false);
    return new CheckAnnotationAdapter(super.visitAnnotation(name, descriptor));
  }

  @Override
  public AnnotationVisitor visitArray(final String name) {
    checkVisitEndNotCalled();
    checkName(name);
    return new CheckAnnotationAdapter(super.visitArray(name), false);
  }

  @Override
  public void visitEnd() {
    checkVisitEndNotCalled();
    visitEndCalled = true;
    super.visitEnd();
  }

  private void checkName(final String name) {
    if (useNamedValue && name == null) {
      throw new IllegalArgumentException("Annotation value name must not be null");
    }
  }

  private void checkVisitEndNotCalled() {
    if (visitEndCalled) {
      throw new IllegalStateException("Cannot call a visit method after visitEnd has been called");
    }
  }
}