org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/TextBuiltin.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.pgm;
  40
  41 import java.io.BufferedWriter;
  42 import java.io.IOException;
  43 import java.io.OutputStreamWriter;
  44 import java.io.PrintWriter;
  45
  46 import org.spearce.jgit.lib.Constants;
  47 import org.spearce.jgit.lib.ObjectId;
  48 import org.spearce.jgit.lib.Repository;
  49
  50 /**
  51  * Abstract command which can be invoked from the command line.
  52  * <p>
  53  * Commands are configured with a single "current" repository and then the
  54  * {@link #execute(String[])} method is invoked with the arguments that appear
  55  * on the command line after the command name.
  56  * <p>
  57  * Command constructors should perform as little work as possible as they may be
  58  * invoked very early during process loading, and the command may not execute
  59  * even though it was constructed.
  60  */
  61 public abstract class TextBuiltin {
  62         protected static final String REFS_HEADS = Constants.HEADS_PREFIX + "/";
  63
  64         protected static final String REFS_REMOTES = Constants.REMOTES_PREFIX + "/";
  65
  66         protected static final String REFS_TAGS = Constants.TAGS_PREFIX + "/";
  67
  68         private String commandName;
  69
  70         /** Stream to output to, typically this is standard output. */
  71         protected PrintWriter out;
  72
  73         /** Git repository the command was invoked within. */
  74         protected Repository db;
  75
  76         /**
  77          * Set the name this command can be invoked as on the command line.
  78          *
  79          * @param name
  80          *            the name of the command.
  81          */
  82         public void setCommandName(final String name) {
  83                 commandName = name;
  84         }
  85
  86         void init(final Repository repo) {
  87                 try {
  88                         out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
  89                                         System.out, "UTF-8")));
  90                 } catch (IOException e) {
  91                         throw die("cannot create output stream");
  92                 }
  93                 db = repo;
  94         }
  95
  96         /**
  97          * Perform the action(s) of this command.
  98          *
  99          * @param args
 100          *            command line arguments passed after the command name.
 101          * @throws Exception
 102          *             an error occurred while processing the command. The main
 103          *             framework will catch the exception and print a message on
 104          *             standard error.
 105          */
 106         public abstract void execute(String[] args) throws Exception;
 107
 108         /**
 109          * @return the repository this command accesses.
 110          */
 111         public Repository getRepository() {
 112                 return db;
 113         }
 114
 115         protected ObjectId resolve(final String s) throws IOException {
 116                 final ObjectId r = db.resolve(s);
 117                 if (r == null)
 118                         throw die("Not a revision: " + s);
 119                 return r;
 120         }
 121
 122         protected static Die die(final String why) {
 123                 return new Die(why);
 124         }
 125
 126         protected static String abbreviateObject(final ObjectId id) {
 127                 return id.toString().substring(0, 7);
 128         }
 129
 130         protected String abbreviateRef(String dst, boolean abbreviateRemote) {
 131                 if (dst.startsWith(REFS_HEADS))
 132                         dst = dst.substring(REFS_HEADS.length());
 133                 else if (dst.startsWith(REFS_TAGS))
 134                         dst = dst.substring(REFS_TAGS.length());
 135                 else if (abbreviateRemote && dst.startsWith(REFS_REMOTES))
 136                         dst = dst.substring(REFS_REMOTES.length());
 137                 return dst;
 138         }
 139 }