1 | // Copyright (c) 2011 The LevelDB Authors. All rights reserved. |
2 | // Use of this source code is governed by a BSD-style license that can be |
3 | // found in the LICENSE file. See the AUTHORS file for names of contributors. |
4 | |
5 | #include "db/filename.h" |
6 | |
7 | #include <cassert> |
8 | #include <cstdio> |
9 | |
10 | #include "db/dbformat.h" |
11 | #include "leveldb/env.h" |
12 | #include "util/logging.h" |
13 | |
14 | namespace leveldb { |
15 | |
16 | // A utility routine: write "data" to the named file and Sync() it. |
17 | Status WriteStringToFileSync(Env* env, const Slice& data, |
18 | const std::string& fname); |
19 | |
20 | static std::string MakeFileName(const std::string& dbname, uint64_t number, |
21 | const char* suffix) { |
22 | char buf[100]; |
23 | std::snprintf(buf, sizeof(buf), "/%06llu.%s" , |
24 | static_cast<unsigned long long>(number), suffix); |
25 | return dbname + buf; |
26 | } |
27 | |
28 | std::string LogFileName(const std::string& dbname, uint64_t number) { |
29 | assert(number > 0); |
30 | return MakeFileName(dbname, number, "log" ); |
31 | } |
32 | |
33 | std::string TableFileName(const std::string& dbname, uint64_t number) { |
34 | assert(number > 0); |
35 | return MakeFileName(dbname, number, "ldb" ); |
36 | } |
37 | |
38 | std::string SSTTableFileName(const std::string& dbname, uint64_t number) { |
39 | assert(number > 0); |
40 | return MakeFileName(dbname, number, "sst" ); |
41 | } |
42 | |
43 | std::string DescriptorFileName(const std::string& dbname, uint64_t number) { |
44 | assert(number > 0); |
45 | char buf[100]; |
46 | std::snprintf(buf, sizeof(buf), "/MANIFEST-%06llu" , |
47 | static_cast<unsigned long long>(number)); |
48 | return dbname + buf; |
49 | } |
50 | |
51 | std::string CurrentFileName(const std::string& dbname) { |
52 | return dbname + "/CURRENT" ; |
53 | } |
54 | |
55 | std::string LockFileName(const std::string& dbname) { return dbname + "/LOCK" ; } |
56 | |
57 | std::string TempFileName(const std::string& dbname, uint64_t number) { |
58 | assert(number > 0); |
59 | return MakeFileName(dbname, number, "dbtmp" ); |
60 | } |
61 | |
62 | std::string InfoLogFileName(const std::string& dbname) { |
63 | return dbname + "/LOG" ; |
64 | } |
65 | |
66 | // Return the name of the old info log file for "dbname". |
67 | std::string OldInfoLogFileName(const std::string& dbname) { |
68 | return dbname + "/LOG.old" ; |
69 | } |
70 | |
71 | // Owned filenames have the form: |
72 | // dbname/CURRENT |
73 | // dbname/LOCK |
74 | // dbname/LOG |
75 | // dbname/LOG.old |
76 | // dbname/MANIFEST-[0-9]+ |
77 | // dbname/[0-9]+.(log|sst|ldb) |
78 | bool ParseFileName(const std::string& filename, uint64_t* number, |
79 | FileType* type) { |
80 | Slice rest(filename); |
81 | if (rest == "CURRENT" ) { |
82 | *number = 0; |
83 | *type = kCurrentFile; |
84 | } else if (rest == "LOCK" ) { |
85 | *number = 0; |
86 | *type = kDBLockFile; |
87 | } else if (rest == "LOG" || rest == "LOG.old" ) { |
88 | *number = 0; |
89 | *type = kInfoLogFile; |
90 | } else if (rest.starts_with("MANIFEST-" )) { |
91 | rest.remove_prefix(strlen("MANIFEST-" )); |
92 | uint64_t num; |
93 | if (!ConsumeDecimalNumber(&rest, &num)) { |
94 | return false; |
95 | } |
96 | if (!rest.empty()) { |
97 | return false; |
98 | } |
99 | *type = kDescriptorFile; |
100 | *number = num; |
101 | } else { |
102 | // Avoid strtoull() to keep filename format independent of the |
103 | // current locale |
104 | uint64_t num; |
105 | if (!ConsumeDecimalNumber(&rest, &num)) { |
106 | return false; |
107 | } |
108 | Slice suffix = rest; |
109 | if (suffix == Slice(".log" )) { |
110 | *type = kLogFile; |
111 | } else if (suffix == Slice(".sst" ) || suffix == Slice(".ldb" )) { |
112 | *type = kTableFile; |
113 | } else if (suffix == Slice(".dbtmp" )) { |
114 | *type = kTempFile; |
115 | } else { |
116 | return false; |
117 | } |
118 | *number = num; |
119 | } |
120 | return true; |
121 | } |
122 | |
123 | Status SetCurrentFile(Env* env, const std::string& dbname, |
124 | uint64_t descriptor_number) { |
125 | // Remove leading "dbname/" and add newline to manifest file name |
126 | std::string manifest = DescriptorFileName(dbname, descriptor_number); |
127 | Slice contents = manifest; |
128 | assert(contents.starts_with(dbname + "/" )); |
129 | contents.remove_prefix(dbname.size() + 1); |
130 | std::string tmp = TempFileName(dbname, descriptor_number); |
131 | Status s = WriteStringToFileSync(env, contents.ToString() + "\n" , tmp); |
132 | if (s.ok()) { |
133 | s = env->RenameFile(tmp, CurrentFileName(dbname)); |
134 | } |
135 | if (!s.ok()) { |
136 | env->RemoveFile(tmp); |
137 | } |
138 | return s; |
139 | } |
140 | |
141 | } // namespace leveldb |
142 | |