org.spearce.jgit/src/org/spearce/jgit/treewalk/EmptyTreeIterator.java

   1 /*
   2  * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
   3  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
   4  *
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or
   8  * without modification, are permitted provided that the following
   9  * conditions are met:
  10  *
  11  * - Redistributions of source code must retain the above copyright
  12  *   notice, this list of conditions and the following disclaimer.
  13  *
  14  * - Redistributions in binary form must reproduce the above
  15  *   copyright notice, this list of conditions and the following
  16  *   disclaimer in the documentation and/or other materials provided
  17  *   with the distribution.
  18  *
  19  * - Neither the name of the Git Development Community nor the
  20  *   names of its contributors may be used to endorse or promote
  21  *   products derived from this software without specific prior
  22  *   written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  25  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  26  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  29  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  32  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  33  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  34  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  36  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 package org.spearce.jgit.treewalk;
  40
  41 import java.io.IOException;
  42
  43 import org.spearce.jgit.errors.CorruptObjectException;
  44 import org.spearce.jgit.errors.IncorrectObjectTypeException;
  45 import org.spearce.jgit.lib.ObjectId;
  46 import org.spearce.jgit.lib.Repository;
  47
  48 /** Iterator over an empty tree (a directory with no files). */
  49 public class EmptyTreeIterator extends AbstractTreeIterator {
  50         /** Create a new iterator with no parent. */
  51         public EmptyTreeIterator() {
  52                 // Create a root empty tree.
  53         }
  54
  55         EmptyTreeIterator(final AbstractTreeIterator p) {
  56                 super(p);
  57                 pathLen = pathOffset;
  58         }
  59
  60         @Override
  61         public AbstractTreeIterator createSubtreeIterator(final Repository repo)
  62                         throws IncorrectObjectTypeException, IOException {
  63                 return new EmptyTreeIterator(this);
  64         }
  65
  66         @Override
  67         public ObjectId getEntryObjectId() {
  68                 return ObjectId.zeroId();
  69         }
  70
  71         @Override
  72         public byte[] idBuffer() {
  73                 return zeroid;
  74         }
  75
  76         @Override
  77         public int idOffset() {
  78                 return 0;
  79         }
  80
  81         @Override
  82         public boolean eof() {
  83                 return true;
  84         }
  85
  86         @Override
  87         public void next(final int delta) throws CorruptObjectException {
  88                 // Do nothing.
  89         }
  90
  91         @Override
  92         public void back(final int delta) throws CorruptObjectException {
  93                 // Do nothing.
  94         }
  95
  96         @Override
  97         public void stopWalk() {
  98                 if (parent != null)
  99                         parent.stopWalk();
 100         }
 101 }