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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.

There is a newer version: 9.1.6

/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2020 Guardsquare NV
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package proguard.classfile.editor;

import proguard.classfile.*;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;

/**
 * This {@link ConstantVisitor} remaps all possible indices of bootstrap methods of the constants
 * that it visits, based on a given index map.
 *
 * @author Eric Lafortune
 */
public class BootstrapMethodRemapper implements ConstantVisitor {
  private int[] bootstrapMethodIndexMap;

  // Ignore (skip) lingering InvokeDynamic constants that
  // refer to removed bootstrap methods.
  private final boolean ignoreDanglingConstants;

  public BootstrapMethodRemapper() {
    this(false);
  }

  public BootstrapMethodRemapper(boolean ignoreDanglingConstants) {
    this.ignoreDanglingConstants = ignoreDanglingConstants;
  }

  /** Sets the given mapping of old constant pool entry indexes to their new indexes. */
  public void setBootstrapMethodIndexMap(int[] bootstrapMethodIndexMap) {
    this.bootstrapMethodIndexMap = bootstrapMethodIndexMap;
  }

  // Implementations for ConstantVisitor.

  public void visitAnyConstant(Clazz clazz, Constant constant) {}

  public void visitDynamicConstant(Clazz clazz, DynamicConstant dynamicConstant) {
    dynamicConstant.u2bootstrapMethodAttributeIndex =
        remapConstantIndex(dynamicConstant.u2bootstrapMethodAttributeIndex);
  }

  public void visitInvokeDynamicConstant(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant) {
    invokeDynamicConstant.u2bootstrapMethodAttributeIndex =
        remapConstantIndex(invokeDynamicConstant.u2bootstrapMethodAttributeIndex);
  }

  // Small utility methods.

  /** Returns the latest bootstrap method index of the entry at the given index. */
  private int remapConstantIndex(int constantIndex) {
    int remappedConstantIndex = bootstrapMethodIndexMap[constantIndex];
    if (remappedConstantIndex < 0) {
      if (ignoreDanglingConstants) {
        return constantIndex;
      } else {
        throw new IllegalArgumentException(
            "Can't remap bootstrap method index [" + constantIndex + "]");
      }
    }

    return remappedConstantIndex;
  }
}