package org.apache.maven.plugins.enforcer;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   */
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.nio.charset.Charset;
  import java.nio.file.Files;
  
  import org.apache.commons.io.input.ReaderInputStream;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleHelper;
  import org.apache.maven.plugins.enforcer.utils.NormalizeLineSeparatorReader;
  import org.apache.maven.plugins.enforcer.utils.NormalizeLineSeparatorReader.LineSeparator;
  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
  
  /**
   * Rule to validate a text file to match the specified checksum.
   *
   * @author Konrad Windszus
   * @see RequireFileChecksum
   */
  public class RequireTextFileChecksum
      extends RequireFileChecksum
  {
      private NormalizeLineSeparatorReader.LineSeparator normalizeLineSeparatorTo = LineSeparator.UNIX;
  
      Charset encoding;
  
      public void setNormalizeLineSeparatorTo( NormalizeLineSeparatorReader.LineSeparator normalizeLineSeparatorTo )
      {
          this.normalizeLineSeparatorTo = normalizeLineSeparatorTo;
      }
  
      public void setEncoding( String encoding )
      {
          this.encoding = Charset.forName( encoding );
      }
  
      @Override
      public void execute( EnforcerRuleHelper helper )
          throws EnforcerRuleException
      {
          // set defaults
          if ( encoding == null )
          {
              // https://maven.apache.org/plugins/maven-resources-plugin/examples/encoding.html
              try
              {
                  String encoding = (String) helper.evaluate( "${project.build.sourceEncoding}" );
                  if ( StringUtils.isBlank( encoding ) )
                  {
                      encoding = System.getProperty( "file.encoding" );
                      helper.getLog().warn( "File encoding has not been set, using platform encoding " + encoding
                          + ". Build is platform dependent!" );
                  }
                  this.encoding = Charset.forName( encoding );
              }
              catch ( ExpressionEvaluationException e )
              {
                  throw new EnforcerRuleException( "Unable to retrieve the project's build source encoding "
                      + "(${project.build.sourceEncoding}): ", e );
              }
          }
          super.execute( helper );
      }
  
      @Override
      protected String calculateChecksum()
          throws EnforcerRuleException
      {
          try ( Reader reader = new NormalizeLineSeparatorReader( Files.newBufferedReader( file.toPath(), encoding ),
                                                                  normalizeLineSeparatorTo );
                          InputStream inputStream = new ReaderInputStream( reader, encoding ) )
          {
              return super.calculateChecksum( inputStream );
          }
          catch ( IOException e )
          {
              throw new EnforcerRuleException( "Unable to calculate checksum (with normalized line separators)", e );
         }
     }
 }