CodeDifferenceStrategy.java

  1. /*
  2.  *  Copyright (c) 2001-2024, Jean Tessier
  3.  *  All rights reserved.
  4.  *  
  5.  *  Redistribution and use in source and binary forms, with or without
  6.  *  modification, are permitted provided that the following conditions
  7.  *  are met:
  8.  *  
  9.  *      * Redistributions of source code must retain the above copyright
  10.  *        notice, this list of conditions and the following disclaimer.
  11.  *  
  12.  *      * Redistributions in binary form must reproduce the above copyright
  13.  *        notice, this list of conditions and the following disclaimer in the
  14.  *        documentation and/or other materials provided with the distribution.
  15.  *  
  16.  *      * Neither the name of Jean Tessier nor the names of his contributors
  17.  *        may be used to endorse or promote products derived from this software
  18.  *        without specific prior written permission.
  19.  *  
  20.  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21.  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22.  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  23.  *  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
  24.  *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  25.  *  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  26.  *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  27.  *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  28.  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  29.  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  30.  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31.  */

  32. package com.jeantessier.diff;

  33. import java.util.*;

  34. import org.apache.logging.log4j.*;

  35. import com.jeantessier.classreader.*;
  36. import com.jeantessier.text.*;

  37. public class CodeDifferenceStrategy implements DifferenceStrategy {
  38.     public boolean isPackageDifferent(Map<String, Classfile> oldPackage, Map<String, Classfile> newPackage) {
  39.         return false;
  40.     }

  41.     public boolean isClassDifferent(Classfile oldClass, Classfile newClass) {
  42.         return false;
  43.     }

  44.     public boolean isDeclarationModified(Classfile oldClass, Classfile newClass) {
  45.         return false;
  46.     }

  47.     public boolean isFieldDifferent(Field_info oldField, Field_info newField) {
  48.         return false;
  49.     }

  50.     public boolean isConstantValueDifferent(ConstantValue_attribute oldValue, ConstantValue_attribute newValue) {
  51.         boolean result;

  52.         if (oldValue != null) {
  53.             result = !oldValue.equals(newValue);
  54.         } else {
  55.             result = oldValue != newValue;
  56.         }

  57.         return result;
  58.     }

  59.     public boolean isMethodDifferent(Method_info oldMethod, Method_info newMethod) {
  60.         return false;
  61.     }

  62.     public boolean isCodeDifferent(Code_attribute oldCode, Code_attribute newCode) {
  63.         boolean result;

  64.         if (oldCode != null && newCode != null) {
  65.             result = oldCode.getCode().length != newCode.getCode().length;

  66.             Iterator<Instruction> oldIterator = oldCode.iterator();
  67.             Iterator<Instruction> newIterator = newCode.iterator();

  68.             while (!result && oldIterator.hasNext() && newIterator.hasNext()) {
  69.                 Instruction oldInstruction = oldIterator.next();
  70.                 Instruction newInstruction = newIterator.next();
  71.                 result = !oldInstruction.equals(newInstruction);
  72.             }

  73.             LogManager.getLogger(getClass()).debug("Code compare for {}", () -> oldCode.getOwner());
  74.             LogManager.getLogger(getClass()).debug("old code: {}", () -> Hex.toString(oldCode.getCode()));
  75.             LogManager.getLogger(getClass()).debug("new code: {}", () -> Hex.toString(newCode.getCode()));
  76.             LogManager.getLogger(getClass()).debug(result ? "[different]" : "[same]");
  77.         } else {
  78.             result = oldCode != newCode;
  79.         }

  80.         return result;
  81.     }
  82. }