org.spearce.jgit/src/org/spearce/jgit/transport/PacketLineIn.java

   1 /*
   2  * Copyright (C) 2008, 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.transport;
  40
  41 import java.io.IOException;
  42 import java.io.InputStream;
  43 import java.util.Arrays;
  44
  45 import org.spearce.jgit.errors.PackProtocolException;
  46 import org.spearce.jgit.lib.Constants;
  47 import org.spearce.jgit.lib.MutableObjectId;
  48 import org.spearce.jgit.lib.ProgressMonitor;
  49 import org.spearce.jgit.util.NB;
  50
  51 class PacketLineIn {
  52         private static final byte fromhex[];
  53
  54         static {
  55                 fromhex = new byte['f' + 1];
  56                 Arrays.fill(fromhex, (byte) -1);
  57                 for (char i = '0'; i <= '9'; i++)
  58                         fromhex[i] = (byte) (i - '0');
  59                 for (char i = 'a'; i <= 'f'; i++)
  60                         fromhex[i] = (byte) ((i - 'a') + 10);
  61         }
  62
  63         static enum AckNackResult {
  64                 /** NAK */
  65                 NAK,
  66                 /** ACK */
  67                 ACK,
  68                 /** ACK + continue */
  69                 ACK_CONTINUE
  70         }
  71
  72         private final InputStream in;
  73
  74         private final byte[] lenbuffer;
  75
  76         PacketLineIn(final InputStream i) {
  77                 in = i;
  78                 lenbuffer = new byte[4];
  79         }
  80
  81         InputStream sideband(final ProgressMonitor pm) {
  82                 return new SideBandInputStream(this, in, pm);
  83         }
  84
  85         AckNackResult readACK(final MutableObjectId returnedId) throws IOException {
  86                 final String line = readString();
  87                 if (line.length() == 0)
  88                         throw new PackProtocolException("Expected ACK/NAK, found EOF");
  89                 if ("NAK".equals(line))
  90                         return AckNackResult.NAK;
  91                 if (line.startsWith("ACK ")) {
  92                         returnedId.fromString(line.substring(4, 44));
  93                         if (line.indexOf("continue", 44) != -1)
  94                                 return AckNackResult.ACK_CONTINUE;
  95                         return AckNackResult.ACK;
  96                 }
  97                 throw new PackProtocolException("Expected ACK/NAK, got: " + line);
  98         }
  99
 100         String readString() throws IOException {
 101                 int len = readLength();
 102                 if (len == 0)
 103                         return "";
 104
 105                 len -= 5; // length header (4 bytes) and trailing LF.
 106
 107                 final byte[] raw = new byte[len];
 108                 NB.readFully(in, raw, 0, len);
 109                 readLF();
 110                 return new String(raw, 0, len, Constants.CHARACTER_ENCODING);
 111         }
 112
 113         private void readLF() throws IOException {
 114                 if (in.read() != '\n')
 115                         throw new IOException("Protocol error: expected LF");
 116         }
 117
 118         int readLength() throws IOException {
 119                 NB.readFully(in, lenbuffer, 0, 4);
 120                 try {
 121                         int r = fromhex[lenbuffer[0]] << 4;
 122
 123                         r |= fromhex[lenbuffer[1]];
 124                         r <<= 4;
 125
 126                         r |= fromhex[lenbuffer[2]];
 127                         r <<= 4;
 128
 129                         r |= fromhex[lenbuffer[3]];
 130                         if (r < 0)
 131                                 throw new ArrayIndexOutOfBoundsException();
 132                         return r;
 133                 } catch (ArrayIndexOutOfBoundsException err) {
 134                         throw new IOException("Invalid packet line header: "
 135                                         + (char) lenbuffer[0] + (char) lenbuffer[1]
 136                                         + (char) lenbuffer[2] + (char) lenbuffer[3]);
 137                 }
 138         }
 139 }