src/leveldb/db/filename.cc

   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 <ctype.h>
   6 #include <stdio.h>
   7 #include "db/filename.h"
   8 #include "db/dbformat.h"
   9 #include "leveldb/env.h"
  10 #include "util/logging.h"
  11
  12 namespace leveldb {
  13
  14 // A utility routine: write "data" to the named file and Sync() it.
  15 extern Status WriteStringToFileSync(Env* env, const Slice& data,
  16                                     const std::string& fname);
  17
  18 static std::string MakeFileName(const std::string& name, uint64_t number,
  19                                 const char* suffix) {
  20   char buf[100];
  21   snprintf(buf, sizeof(buf), "/%06llu.%s",
  22            static_cast<unsigned long long>(number),
  23            suffix);
  24   return name + buf;
  25 }
  26
  27 std::string LogFileName(const std::string& name, uint64_t number) {
  28   assert(number > 0);
  29   return MakeFileName(name, number, "log");
  30 }
  31
  32 std::string TableFileName(const std::string& name, uint64_t number) {
  33   assert(number > 0);
  34   return MakeFileName(name, number, "ldb");
  35 }
  36
  37 std::string SSTTableFileName(const std::string& name, uint64_t number) {
  38   assert(number > 0);
  39   return MakeFileName(name, number, "sst");
  40 }
  41
  42 std::string DescriptorFileName(const std::string& dbname, uint64_t number) {
  43   assert(number > 0);
  44   char buf[100];
  45   snprintf(buf, sizeof(buf), "/MANIFEST-%06llu",
  46            static_cast<unsigned long long>(number));
  47   return dbname + buf;
  48 }
  49
  50 std::string CurrentFileName(const std::string& dbname) {
  51   return dbname + "/CURRENT";
  52 }
  53
  54 std::string LockFileName(const std::string& dbname) {
  55   return dbname + "/LOCK";
  56 }
  57
  58 std::string TempFileName(const std::string& dbname, uint64_t number) {
  59   assert(number > 0);
  60   return MakeFileName(dbname, number, "dbtmp");
  61 }
  62
  63 std::string InfoLogFileName(const std::string& dbname) {
  64   return dbname + "/LOG";
  65 }
  66
  67 // Return the name of the old info log file for "dbname".
  68 std::string OldInfoLogFileName(const std::string& dbname) {
  69   return dbname + "/LOG.old";
  70 }
  71
  72
  73 // Owned filenames have the form:
  74 //    dbname/CURRENT
  75 //    dbname/LOCK
  76 //    dbname/LOG
  77 //    dbname/LOG.old
  78 //    dbname/MANIFEST-[0-9]+
  79 //    dbname/[0-9]+.(log|sst|ldb)
  80 bool ParseFileName(const std::string& fname,
  81                    uint64_t* number,
  82                    FileType* type) {
  83   Slice rest(fname);
  84   if (rest == "CURRENT") {
  85     *number = 0;
  86     *type = kCurrentFile;
  87   } else if (rest == "LOCK") {
  88     *number = 0;
  89     *type = kDBLockFile;
  90   } else if (rest == "LOG" || rest == "LOG.old") {
  91     *number = 0;
  92     *type = kInfoLogFile;
  93   } else if (rest.starts_with("MANIFEST-")) {
  94     rest.remove_prefix(strlen("MANIFEST-"));
  95     uint64_t num;
  96     if (!ConsumeDecimalNumber(&rest, &num)) {
  97       return false;
  98     }
  99     if (!rest.empty()) {
 100       return false;
 101     }
 102     *type = kDescriptorFile;
 103     *number = num;
 104   } else {
 105     // Avoid strtoull() to keep filename format independent of the
 106     // current locale
 107     uint64_t num;
 108     if (!ConsumeDecimalNumber(&rest, &num)) {
 109       return false;
 110     }
 111     Slice suffix = rest;
 112     if (suffix == Slice(".log")) {
 113       *type = kLogFile;
 114     } else if (suffix == Slice(".sst") || suffix == Slice(".ldb")) {
 115       *type = kTableFile;
 116     } else if (suffix == Slice(".dbtmp")) {
 117       *type = kTempFile;
 118     } else {
 119       return false;
 120     }
 121     *number = num;
 122   }
 123   return true;
 124 }
 125
 126 Status SetCurrentFile(Env* env, const std::string& dbname,
 127                       uint64_t descriptor_number) {
 128   // Remove leading "dbname/" and add newline to manifest file name
 129   std::string manifest = DescriptorFileName(dbname, descriptor_number);
 130   Slice contents = manifest;
 131   assert(contents.starts_with(dbname + "/"));
 132   contents.remove_prefix(dbname.size() + 1);
 133   std::string tmp = TempFileName(dbname, descriptor_number);
 134   Status s = WriteStringToFileSync(env, contents.ToString() + "\n", tmp);
 135   if (s.ok()) {
 136     s = env->RenameFile(tmp, CurrentFileName(dbname));
 137   }
 138   if (!s.ok()) {
 139     env->DeleteFile(tmp);
 140   }
 141   return s;
 142 }
 143
 144 }  // namespace leveldb