1 /*
2 * Copyright (C) 2016, Google Inc.
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
44 package org.eclipse.jgit.internal.ketch;
45
46 import java.net.URISyntaxException;
47 import java.util.concurrent.ConcurrentHashMap;
48 import java.util.concurrent.ConcurrentMap;
49 import java.util.concurrent.locks.Lock;
50 import java.util.concurrent.locks.ReentrantLock;
51
52 import org.eclipse.jgit.internal.storage.dfs.DfsRepository;
53 import org.eclipse.jgit.lib.Repository;
54
55 /**
56 * A cache of live leader instances, keyed by repository.
57 * <p>
58 * Ketch only assigns a leader to a repository when needed. If
59 * {@link #get(Repository)} is called for a repository that does not have a
60 * leader, the leader is created and added to the cache.
61 */
62 public class KetchLeaderCache {
63 private final KetchSystem system;
64 private final ConcurrentMap<String, KetchLeader> leaders;
65 private final Lock startLock;
66
67 /**
68 * Initialize a new leader cache.
69 *
70 * @param system
71 * system configuration for the leaders
72 */
73 public KetchLeaderCache(KetchSystem system) {
74 this.system = system;
75 leaders = new ConcurrentHashMap<>();
76 startLock = new ReentrantLock(true /* fair */);
77 }
78
79 /**
80 * Lookup the leader instance for a given repository.
81 *
82 * @param repo
83 * repository to get the leader for.
84 * @return the leader instance for the repository.
85 * @throws java.net.URISyntaxException
86 * remote configuration contains an invalid URL.
87 */
88 public KetchLeader get(Repository repo)
89 throws URISyntaxException {
90 String key = computeKey(repo);
91 KetchLeader leader = leaders.get(key);
92 if (leader != null) {
93 return leader;
94 }
95 return startLeader(key, repo);
96 }
97
98 private KetchLeader startLeader(String key, Repository repo)
99 throws URISyntaxException {
100 startLock.lock();
101 try {
102 KetchLeader leader = leaders.get(key);
103 if (leader != null) {
104 return leader;
105 }
106 leader = system.createLeader(repo);
107 leaders.put(key, leader);
108 return leader;
109 } finally {
110 startLock.unlock();
111 }
112 }
113
114 private static String computeKey(Repository repo) {
115 if (repo instanceof DfsRepository) {
116 DfsRepository dfs = (DfsRepository) repo;
117 return dfs.getDescription().getRepositoryName();
118 }
119
120 if (repo.getDirectory() != null) {
121 return repo.getDirectory().toURI().toString();
122 }
123
124 throw new IllegalArgumentException();
125 }
126 }