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.kohsuke.args4j.CmdLineException;
  47 import org.kohsuke.args4j.Option;
  48 import org.spearce.jgit.lib.Constants;
  49 import org.spearce.jgit.lib.ObjectId;
  50 import org.spearce.jgit.lib.Repository;
  51 import org.spearce.jgit.pgm.opt.CmdLineParser;
  52 import org.spearce.jgit.revwalk.RevWalk;
  53
  54 /**
  55  * Abstract command which can be invoked from the command line.
  56  * <p>
  57  * Commands are configured with a single "current" repository and then the
  58  * {@link #execute(String[])} method is invoked with the arguments that appear
  59  * on the command line after the command name.
  60  * <p>
  61  * Command constructors should perform as little work as possible as they may be
  62  * invoked very early during process loading, and the command may not execute
  63  * even though it was constructed.
  64  */
  65 public abstract class TextBuiltin {
  66         protected static final String REFS_HEADS = Constants.HEADS_PREFIX + "/";
  67
  68         protected static final String REFS_REMOTES = Constants.REMOTES_PREFIX + "/";
  69
  70         protected static final String REFS_TAGS = Constants.TAGS_PREFIX + "/";
  71
  72         private String commandName;
  73
  74         @Option(name = "--help", usage = "display this help text", aliases = { "-h" })
  75         private boolean help;
  76
  77         /** Stream to output to, typically this is standard output. */
  78         protected PrintWriter out;
  79
  80         /** Git repository the command was invoked within. */
  81         protected Repository db;
  82
  83         /** RevWalk used during command line parsing, if it was required. */
  84         protected RevWalk argWalk;
  85
  86         /**
  87          * Set the name this command can be invoked as on the command line.
  88          *
  89          * @param name
  90          *            the name of the command.
  91          */
  92         public void setCommandName(final String name) {
  93                 commandName = name;
  94         }
  95
  96         void init(final Repository repo) {
  97                 try {
  98                         out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
  99                                         System.out, "UTF-8")));
 100                 } catch (IOException e) {
 101                         throw die("cannot create output stream");
 102                 }
 103                 db = repo;
 104         }
 105
 106         /**
 107          * Parse arguments and run this command.
 108          *
 109          * @param args
 110          *            command line arguments passed after the command name.
 111          * @throws Exception
 112          *             an error occurred while processing the command. The main
 113          *             framework will catch the exception and print a message on
 114          *             standard error.
 115          */
 116         public void execute(String[] args) throws Exception {
 117                 parseArguments(args);
 118                 run();
 119         }
 120
 121         /**
 122          * Parses the command line arguments prior to running.
 123          * <p>
 124          * This method should only be invoked by {@link #execute(String[])}, prior
 125          * to calling {@link #run()}. The default implementation parses all
 126          * arguments into this object's instance fields.
 127          *
 128          * @param args
 129          *            the arguments supplied on the command line, if any.
 130          */
 131         protected void parseArguments(final String[] args) {
 132                 final CmdLineParser clp = new CmdLineParser(this);
 133                 try {
 134                         clp.parseArgument(args);
 135                 } catch (CmdLineException err) {
 136                         if (!help) {
 137                                 System.err.println("fatal: " + err.getMessage());
 138                                 System.exit(1);
 139                         }
 140                 }
 141
 142                 if (help) {
 143                         System.err.print("jgit ");
 144                         System.err.print(commandName);
 145                         clp.printSingleLineUsage(System.err);
 146                         System.err.println();
 147
 148                         System.err.println();
 149
 150                         clp.printUsage(System.err);
 151                         System.err.println();
 152
 153                         System.exit(1);
 154                 }
 155
 156                 argWalk = clp.getRevWalkGently();
 157         }
 158
 159         /**
 160          * Perform the actions of this command.
 161          * <p>
 162          * This method should only be invoked by {@link #execute(String[])}.
 163          *
 164          * @throws Exception
 165          *             an error occurred while processing the command. The main
 166          *             framework will catch the exception and print a message on
 167          *             standard error.
 168          */
 169         protected void run() throws Exception {
 170                 throw die("Override either execute (legacy) or run (new style).");
 171         }
 172
 173         /**
 174          * @return the repository this command accesses.
 175          */
 176         public Repository getRepository() {
 177                 return db;
 178         }
 179
 180         protected ObjectId resolve(final String s) throws IOException {
 181                 final ObjectId r = db.resolve(s);
 182                 if (r == null)
 183                         throw die("Not a revision: " + s);
 184                 return r;
 185         }
 186
 187         protected static Die die(final String why) {
 188                 return new Die(why);
 189         }
 190
 191         protected static String abbreviateObject(final ObjectId id) {
 192                 return id.toString().substring(0, 7);
 193         }
 194
 195         protected String abbreviateRef(String dst, boolean abbreviateRemote) {
 196                 if (dst.startsWith(REFS_HEADS))
 197                         dst = dst.substring(REFS_HEADS.length());
 198                 else if (dst.startsWith(REFS_TAGS))
 199                         dst = dst.substring(REFS_TAGS.length());
 200                 else if (abbreviateRemote && dst.startsWith(REFS_REMOTES))
 201                         dst = dst.substring(REFS_REMOTES.length());
 202                 return dst;
 203         }
 204 }