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.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.commons.codec.digest.DigestUtils;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleException;
  import org.apache.maven.enforcer.rule.api.EnforcerRuleHelper;
  import org.codehaus.plexus.util.IOUtil;
  
  /**
   * Rule to validate a file to match the specified checksum.
   *
   * @author Edward Samson
   * @author Lyubomyr Shaydariv
   */
  public class RequireFileChecksum
      extends AbstractNonCacheableEnforcerRule
  {
  
      private File file;
  
      private String checksum;
  
      private String type;
  
      private String nonexistentFileMessage;
  
      @Override
      public void execute( EnforcerRuleHelper helper )
          throws EnforcerRuleException
      {
          if ( this.file == null )
          {
              throw new EnforcerRuleException( "Input file unspecified" );
          }
  
          if ( this.type == null )
          {
              throw new EnforcerRuleException( "Hash type unspecified" );
          }
  
          if ( this.checksum == null )
          {
              throw new EnforcerRuleException( "Checksum unspecified" );
          }
  
          if ( !this.file.exists() )
          {
              String message = nonexistentFileMessage;
              if ( message == null )
              {
                  message = "File does not exist: " + this.file.getAbsolutePath();
              }
              throw new EnforcerRuleException( message );
          }
  
          if ( this.file.isDirectory() )
          {
              throw new EnforcerRuleException( "Cannot calculate the checksum of directory: "
                  + this.file.getAbsolutePath() );
          }
  
          if ( !this.file.canRead() )
          {
              throw new EnforcerRuleException( "Cannot read file: " + this.file.getAbsolutePath() );
          }
  
          String checksum = calculateChecksum();
  
          if ( !checksum.equalsIgnoreCase( this.checksum ) )
          {
              String exceptionMessage = getMessage();
              if ( exceptionMessage == null )
              {
                  exceptionMessage = this.type + " hash of " + this.file + " was " + checksum
                      + " but expected " + this.checksum;
              }
             throw new EnforcerRuleException( exceptionMessage );
         }
     }
 
     /**
      * The file to check.
      *
      * @param file file
      */
     public void setFile( File file )
     {
         this.file = file;
     }
 
     /**
      * The expected checksum value.
      *
      * @param checksum checksum
      */
     public void setChecksum( String checksum )
     {
         this.checksum = checksum;
     }
 
     /**
      * The checksum algorithm to use. Possible values: "md5", "sha1", "sha256", "sha384", "sha512".
      *
      * @param type algorithm
      */
     public void setType( String type )
     {
         this.type = type;
     }
 
     /**
      * The friendly message to use when the file does not exist.
      *
      * @param nonexistentFileMessage message
      */
     public void setNonexistentFileMessage( String nonexistentFileMessage )
     {
         this.nonexistentFileMessage = nonexistentFileMessage;
     }
 
     private String calculateChecksum()
         throws EnforcerRuleException
     {
         InputStream inputStream = null;
         try
         {
             inputStream = new FileInputStream( this.file );
             String checksum;
             if ( "md5".equals( this.type ) )
             {
                 checksum = DigestUtils.md5Hex( inputStream );
             }
             else if ( "sha1".equals( this.type ) )
             {
                 checksum = DigestUtils.shaHex( inputStream );
             }
             else if ( "sha256".equals( this.type ) )
             {
                 checksum = DigestUtils.sha256Hex( inputStream );
             }
             else if ( "sha384".equals( this.type ) )
             {
                 checksum = DigestUtils.sha384Hex( inputStream );
             }
             else if ( "sha512".equals( this.type ) )
             {
                 checksum = DigestUtils.sha512Hex( inputStream );
             }
             else
             {
                 throw new EnforcerRuleException( "Unsupported hash type: " + this.type );
             }
             return checksum;
         }
         catch ( IOException e )
         {
             throw new EnforcerRuleException( "Unable to calculate checksum", e );
         }
         finally
         {
             IOUtil.close( inputStream );
         }
     }
 }