1 /*
2 * Copyright (C) 2018, Google LLC.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43 package org.eclipse.jgit.internal.transport.parser;
44
45 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_AGENT;
46
47 import java.util.Collections;
48 import java.util.HashSet;
49 import java.util.Set;
50
51 import org.eclipse.jgit.annotations.Nullable;
52 import org.eclipse.jgit.errors.PackProtocolException;
53 import org.eclipse.jgit.internal.JGitText;
54
55 /**
56 * In the pack negotiation phase (protocol v0/v1), the client sends a list of
57 * wants. The first "want" line is special, as it (can) have a list of
58 * capabilities appended.
59 *
60 * E.g. "want oid cap1 cap2 cap3"
61 *
62 * Do not confuse this line with the first one in the reference advertisement,
63 * which is sent by the server, looks like
64 * "b8f7c471373b8583ced0025cfad8c9916c484b76 HEAD\0 cap1 cap2 cap3" and is
65 * parsed by the BasePackConnection.readAdvertisedRefs method.
66 *
67 * This class parses the input want line and holds the results: the actual want
68 * line and the capabilities.
69 *
70 */
71 public class FirstWant {
72 private final String line;
73
74 private final Set<String> capabilities;
75
76 @Nullable
77 private final String agent;
78
79 private static final String AGENT_PREFIX = OPTION_AGENT + '=';
80
81 /**
82 * Parse the first want line in the protocol v0/v1 pack negotiation.
83 *
84 * @param line
85 * line from the client.
86 * @return an instance of FirstWant
87 * @throws PackProtocolException
88 * if the line doesn't follow the protocol format.
89 */
90 public static FirstWant fromLine(String line) throws PackProtocolException {
91 String wantLine;
92 Set<String> capabilities;
93 String agent = null;
94
95 if (line.length() > 45) {
96 String opt = line.substring(45);
97 if (!opt.startsWith(" ")) { //$NON-NLS-1$
98 throw new PackProtocolException(JGitText.get().wantNoSpaceWithCapabilities);
99 }
100 opt = opt.substring(1);
101
102 HashSet<String> opts = new HashSet<>();
103 for (String clientCapability : opt.split(" ")) { //$NON-NLS-1$
104 if (clientCapability.startsWith(AGENT_PREFIX)) {
105 agent = clientCapability.substring(AGENT_PREFIX.length());
106 } else {
107 opts.add(clientCapability);
108 }
109 }
110 wantLine = line.substring(0, 45);
111 capabilities = Collections.unmodifiableSet(opts);
112 } else {
113 wantLine = line;
114 capabilities = Collections.emptySet();
115 }
116
117 return new FirstWant(wantLine, capabilities, agent);
118 }
119
120 private FirstWant(String line, Set<String> capabilities,
121 @Nullable String agent) {
122 this.line = line;
123 this.capabilities = capabilities;
124 this.agent = agent;
125 }
126
127 /** @return non-capabilities part of the line. */
128 public String getLine() {
129 return line;
130 }
131
132 /**
133 * @return capabilities parsed from the line as an immutable set (excluding
134 * agent).
135 */
136 public Set<String> getCapabilities() {
137 return capabilities;
138 }
139
140 /** @return client user agent parsed from the line. */
141 @Nullable
142 public String getAgent() {
143 return agent;
144 }
145 }