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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.attribute.*;
import proguard.classfile.attribute.visitor.*;

/**
 * This {@link AttributeVisitor} adds the line numbers of all line number attributes that it visits
 * to the given target line number attribute. It ensures that the sources of the line numbers are
 * preserved or set.
 */
public class LineNumberInfoAdder implements AttributeVisitor, LineNumberInfoVisitor {
  private final LineNumberTableAttributeEditor lineNumberTableAttributeEditor;

  private String source;

  /**
   * Creates a new LineNumberInfoAdder that will copy line numbers into the given target line number
   * table.
   */
  public LineNumberInfoAdder(LineNumberTableAttribute targetLineNumberTableAttribute) {
    this.lineNumberTableAttributeEditor =
        new LineNumberTableAttributeEditor(targetLineNumberTableAttribute);
  }

  // Implementations for AttributeVisitor.

  public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}

  public void visitLineNumberTableAttribute(
      Clazz clazz,
      Method method,
      CodeAttribute codeAttribute,
      LineNumberTableAttribute lineNumberTableAttribute) {
    // Remember the source.
    source =
        clazz.getName()
            + '.'
            + method.getName(clazz)
            + method.getDescriptor(clazz)
            + ':'
            + lineNumberTableAttribute.getLowestLineNumber()
            + ':'
            + lineNumberTableAttribute.getHighestLineNumber();

    // Copy all line numbers.
    lineNumberTableAttribute.lineNumbersAccept(clazz, method, codeAttribute, this);
  }

  // Implementations for LineNumberInfoVisitor.

  public void visitLineNumberInfo(
      Clazz clazz, Method method, CodeAttribute codeAttribute, LineNumberInfo lineNumberInfo) {
    // Make sure we have a source.
    String newSource = lineNumberInfo.getSource() != null ? lineNumberInfo.getSource() : source;

    // Create a new line number.
    LineNumberInfo newLineNumberInfo =
        new ExtendedLineNumberInfo(
            lineNumberInfo.u2startPC, lineNumberInfo.u2lineNumber, newSource);

    // Add it to the target.
    lineNumberTableAttributeEditor.addLineNumberInfo(newLineNumberInfo);
  }
}