Inside Bitcoin

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 <ctype.h>
8#include <stdio.h>
9
10#include "db/dbformat.h"
11#include "leveldb/env.h"
12#include "util/logging.h"
13
14namespace leveldb {
15
16// A utility routine: write "data" to the named file and Sync() it.
17Status WriteStringToFileSync(Env* env, const Slice& data,
18                             const std::string& fname);
19
20static std::string MakeFileName(const std::string& dbname, uint64_t number,
21                                const char* suffix) {
22  char buf[100];
23  snprintf(buf, sizeof(buf), "/%06llu.%s",
24           static_cast<unsigned long long>(number), suffix);
25  return dbname + buf;
26}
27
28std::string LogFileName(const std::string& dbname, uint64_t number) {
29  assert(number > 0);
30  return MakeFileName(dbname, number, "log");
31}
32
33std::string TableFileName(const std::string& dbname, uint64_t number) {
34  assert(number > 0);
35  return MakeFileName(dbname, number, "ldb");
36}
37
38std::string SSTTableFileName(const std::string& dbname, uint64_t number) {
39  assert(number > 0);
40  return MakeFileName(dbname, number, "sst");
41}
42
43std::string DescriptorFileName(const std::string& dbname, uint64_t number) {
44  assert(number > 0);
45  char buf[100];
46  snprintf(buf, sizeof(buf), "/MANIFEST-%06llu",
47           static_cast<unsigned long long>(number));
48  return dbname + buf;
49}
50
51std::string CurrentFileName(const std::string& dbname) {
52  return dbname + "/CURRENT";
53}
54
55std::string LockFileName(const std::string& dbname) { return dbname + "/LOCK"; }
56
57std::string TempFileName(const std::string& dbname, uint64_t number) {
58  assert(number > 0);
59  return MakeFileName(dbname, number, "dbtmp");
60}
61
62std::string InfoLogFileName(const std::string& dbname) {
63  return dbname + "/LOG";
64}
65
66// Return the name of the old info log file for "dbname".
67std::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)
78bool 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
123Status 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->DeleteFile(tmp);
137  }
138  return s;
139}
140
141}  // namespace leveldb
142