org.spearce.jgit/src/org/spearce/jgit/revwalk/AbstractRevQueue.java

   1 /*
   2  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
   3  *
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or
   7  * without modification, are permitted provided that the following
   8  * conditions are met:
   9  *
  10  * - Redistributions of source code must retain the above copyright
  11  *   notice, this list of conditions and the following disclaimer.
  12  *
  13  * - Redistributions in binary form must reproduce the above
  14  *   copyright notice, this list of conditions and the following
  15  *   disclaimer in the documentation and/or other materials provided
  16  *   with the distribution.
  17  *
  18  * - Neither the name of the Git Development Community nor the
  19  *   names of its contributors may be used to endorse or promote
  20  *   products derived from this software without specific prior
  21  *   written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  24  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  25  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  28  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  31  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  32  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  33  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  35  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 package org.spearce.jgit.revwalk;
  39
  40 abstract class AbstractRevQueue extends Generator {
  41         static final AbstractRevQueue EMPTY_QUEUE = new AlwaysEmptyQueue();
  42
  43         /** Current output flags set for this generator instance. */
  44         int outputType;
  45
  46         /**
  47          * Add a commit to the queue.
  48          * <p>
  49          * This method always adds the commit, even if it is already in the queue or
  50          * previously was in the queue but has already been removed. To control
  51          * queue admission use {@link #add(RevCommit, RevFlag)}.
  52          *
  53          * @param c
  54          *            commit to add.
  55          */
  56         public abstract void add(RevCommit c);
  57
  58         /**
  59          * Add a commit if it does not have a flag set yet, then set the flag.
  60          * <p>
  61          * This method permits the application to test if the commit has the given
  62          * flag; if it does not already have the flag than the commit is added to
  63          * the queue and the flag is set. This later will prevent the commit from
  64          * being added twice.
  65          *
  66          * @param c
  67          *            commit to add.
  68          * @param queueControl
  69          *            flag that controls admission to the queue.
  70          */
  71         public final void add(final RevCommit c, final RevFlag queueControl) {
  72                 if (!c.has(queueControl)) {
  73                         c.add(queueControl);
  74                         add(c);
  75                 }
  76         }
  77
  78         /**
  79          * Add a commit's parents if one does not have a flag set yet.
  80          * <p>
  81          * This method permits the application to test if the commit has the given
  82          * flag; if it does not already have the flag than the commit is added to
  83          * the queue and the flag is set. This later will prevent the commit from
  84          * being added twice.
  85          *
  86          * @param c
  87          *            commit whose parents should be added.
  88          * @param queueControl
  89          *            flag that controls admission to the queue.
  90          */
  91         public final void addParents(final RevCommit c, final RevFlag queueControl) {
  92                 final RevCommit[] pList = c.parents;
  93                 if (pList == null)
  94                         return;
  95                 for (RevCommit p : pList)
  96                         add(p, queueControl);
  97         }
  98
  99         /**
 100          * Remove the first commit from the queue.
 101          *
 102          * @return the first commit of this queue.
 103          */
 104         public abstract RevCommit next();
 105
 106         /** Remove all entries from this queue. */
 107         public abstract void clear();
 108
 109         abstract boolean everbodyHasFlag(int f);
 110
 111         abstract boolean anybodyHasFlag(int f);
 112
 113         @Override
 114         int outputType() {
 115                 return outputType;
 116         }
 117
 118         private static class AlwaysEmptyQueue extends AbstractRevQueue {
 119                 @Override
 120                 public void add(RevCommit c) {
 121                         throw new UnsupportedOperationException();
 122                 }
 123
 124                 @Override
 125                 public RevCommit next() {
 126                         return null;
 127                 }
 128
 129                 @Override
 130                 boolean anybodyHasFlag(int f) {
 131                         return true;
 132                 }
 133
 134                 @Override
 135                 boolean everbodyHasFlag(int f) {
 136                         return true;
 137                 }
 138
 139                 @Override
 140                 public void clear() {
 141                         // Nothing to clear, we have no state.
 142                 }
 143
 144         }
 145 }