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1   package org.apache.maven.plugin.clean;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.io.File;
23  import java.io.IOException;
24  
25  import org.apache.maven.plugin.logging.Log;
26  import org.codehaus.plexus.util.Os;
27  
28  /**
29   * Cleans directories.
30   * 
31   * @author Benjamin Bentmann
32   */
33  class Cleaner
34  {
35  
36      private static final boolean ON_WINDOWS = Os.isFamily( Os.FAMILY_WINDOWS );
37  
38      private final Logger logDebug;
39  
40      private final Logger logInfo;
41  
42      private final Logger logVerbose;
43  
44      private final Logger logWarn;
45  
46      /**
47       * Creates a new cleaner.
48       * 
49       * @param log The logger to use, may be <code>null</code> to disable logging.
50       * @param verbose Whether to perform verbose logging.
51       */
52      public Cleaner( final Log log, boolean verbose )
53      {
54          logDebug = ( log == null || !log.isDebugEnabled() ) ? null : new Logger()
55          {
56              public void log( CharSequence message )
57              {
58                  log.debug( message );
59              }
60          };
61  
62          logInfo = ( log == null || !log.isInfoEnabled() ) ? null : new Logger()
63          {
64              public void log( CharSequence message )
65              {
66                  log.info( message );
67              }
68          };
69  
70          logWarn = ( log == null || !log.isWarnEnabled() ) ? null : new Logger()
71          {
72              public void log( CharSequence message )
73              {
74                  log.warn( message );
75              }
76          };
77  
78          logVerbose = verbose ? logInfo : logDebug;
79      }
80  
81      /**
82       * Deletes the specified directories and its contents.
83       * 
84       * @param basedir The directory to delete, must not be <code>null</code>. Non-existing directories will be silently
85       *            ignored.
86       * @param selector The selector used to determine what contents to delete, may be <code>null</code> to delete
87       *            everything.
88       * @param followSymlinks Whether to follow symlinks.
89       * @param failOnError Whether to abort with an exception in case a selected file/directory could not be deleted.
90       * @throws IOException If a file/directory could not be deleted and <code>failOnError</code> is <code>true</code>.
91       */
92      public void delete( File basedir, Selector selector, boolean followSymlinks, boolean failOnError )
93          throws IOException
94      {
95          if ( !basedir.isDirectory() )
96          {
97              if ( !basedir.exists() )
98              {
99                  if ( logDebug != null )
100                 {
101                     logDebug.log( "Skipping non-existing directory " + basedir );
102                 }
103                 return;
104             }
105             throw new IOException( "Invalid base directory " + basedir );
106         }
107 
108         if ( logInfo != null )
109         {
110             logInfo.log( "Deleting " + basedir + ( selector != null ? " (" + selector + ")" : "" ) );
111         }
112 
113         File file = followSymlinks ? basedir : basedir.getCanonicalFile();
114 
115         delete( file, "", selector, followSymlinks, failOnError );
116     }
117 
118     /**
119      * Deletes the specified file or directory.
120      * 
121      * @param file The file/directory to delete, must not be <code>null</code>. If <code>followSymlinks</code> is
122      *            <code>false</code>, it is assumed that the parent file is canonical.
123      * @param pathname The relative pathname of the file, using {@link File#separatorChar}, must not be
124      *            <code>null</code>.
125      * @param selector The selector used to determine what contents to delete, may be <code>null</code> to delete
126      *            everything.
127      * @param followSymlinks Whether to follow symlinks.
128      * @param failOnError Whether to abort with an exception in case a selected file/directory could not be deleted.
129      * @return The result of the cleaning, never <code>null</code>.
130      * @throws IOException If a file/directory could not be deleted and <code>failOnError</code> is <code>true</code>.
131      */
132     private Result delete( File file, String pathname, Selector selector, boolean followSymlinks, boolean failOnError )
133         throws IOException
134     {
135         Result result = new Result();
136 
137         boolean isDirectory = file.isDirectory();
138 
139         if ( isDirectory )
140         {
141             if ( selector == null || selector.couldHoldSelected( pathname ) )
142             {
143                 File canonical = followSymlinks ? file : file.getCanonicalFile();
144                 if ( followSymlinks || file.equals( canonical ) )
145                 {
146                     String[] filenames = canonical.list();
147                     if ( filenames != null )
148                     {
149                         String prefix = ( pathname.length() > 0 ) ? pathname + File.separatorChar : "";
150                         for ( int i = filenames.length - 1; i >= 0; i-- )
151                         {
152                             String filename = filenames[i];
153                             File child = new File( canonical, filename );
154                             result.update( delete( child, prefix + filename, selector, followSymlinks, failOnError ) );
155                         }
156                     }
157                 }
158                 else if ( logDebug != null )
159                 {
160                     logDebug.log( "Not recursing into symlink " + file );
161                 }
162             }
163             else if ( logDebug != null )
164             {
165                 logDebug.log( "Not recursing into directory without included files " + file );
166             }
167         }
168 
169         if ( !result.excluded && ( selector == null || selector.isSelected( pathname ) ) )
170         {
171             if ( logVerbose != null )
172             {
173                 if ( isDirectory )
174                 {
175                     logVerbose.log( "Deleting directory " + file );
176                 }
177                 else if ( file.exists() )
178                 {
179                     logVerbose.log( "Deleting file " + file );
180                 }
181                 else
182                 {
183                     logVerbose.log( "Deleting dangling symlink " + file );
184                 }
185             }
186             result.failures += delete( file, failOnError );
187         }
188         else
189         {
190             result.excluded = true;
191         }
192 
193         return result;
194     }
195 
196     /**
197      * Deletes the specified file, directory. If the path denotes a symlink, only the link is removed, its target is
198      * left untouched.
199      * 
200      * @param file The file/directory to delete, must not be <code>null</code>.
201      * @param failOnError Whether to abort with an exception in case the file/directory could not be deleted.
202      * @return <code>0</code> if the file was deleted, <code>1</code> otherwise.
203      * @throws IOException If a file/directory could not be deleted and <code>failOnError</code> is <code>true</code>.
204      */
205     private int delete( File file, boolean failOnError )
206         throws IOException
207     {
208         if ( !file.delete() )
209         {
210             if ( ON_WINDOWS )
211             {
212                 // try to release any locks held by non-closed files
213                 System.gc();
214             }
215             try
216             {
217                 Thread.sleep( 10 );
218             }
219             catch ( InterruptedException e )
220             {
221                 // ignore
222             }
223             if ( !file.delete() )
224             {
225                 if ( failOnError )
226                 {
227                     throw new IOException( "Failed to delete " + file );
228                 }
229                 else
230                 {
231                     if ( logWarn != null )
232                     {
233                         logWarn.log( "Failed to delete " + file );
234                     }
235                     return 1;
236                 }
237             }
238         }
239 
240         return 0;
241     }
242 
243     private static class Result
244     {
245 
246         public int failures;
247 
248         public boolean excluded;
249 
250         public void update( Result result )
251         {
252             failures += result.failures;
253             excluded |= result.excluded;
254         }
255 
256     }
257 
258     private static interface Logger
259     {
260 
261         public void log( CharSequence message );
262 
263     }
264 
265 }