ceph/src/rocksdb/db/log_format.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under the BSD-style license found in the
   3 //  LICENSE file in the root directory of this source tree. An additional grant
   4 //  of patent rights can be found in the PATENTS file in the same directory.
   5 //
   6 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
   7 // Use of this source code is governed by a BSD-style license that can be
   8 // found in the LICENSE file. See the AUTHORS file for names of contributors.
   9 //
  10 // Log format information shared by reader and writer.
  11 // See ../doc/log_format.txt for more detail.
  12
  13 #pragma once
  14 namespace rocksdb {
  15 namespace log {
  16
  17 enum RecordType {
  18   // Zero is reserved for preallocated files
  19   kZeroType = 0,
  20   kFullType = 1,
  21
  22   // For fragments
  23   kFirstType = 2,
  24   kMiddleType = 3,
  25   kLastType = 4,
  26
  27   // For recycled log files
  28   kRecyclableFullType = 5,
  29   kRecyclableFirstType = 6,
  30   kRecyclableMiddleType = 7,
  31   kRecyclableLastType = 8,
  32 };
  33 static const int kMaxRecordType = kRecyclableLastType;
  34
  35 static const unsigned int kBlockSize = 32768;
  36
  37 // Header is checksum (4 bytes), length (2 bytes), type (1 byte)
  38 static const int kHeaderSize = 4 + 2 + 1;
  39
  40 // Recyclable header is checksum (4 bytes), type (1 byte), log number
  41 // (4 bytes), length (2 bytes).
  42 static const int kRecyclableHeaderSize = 4 + 1 + 4 + 2;
  43
  44 }  // namespace log
  45 }  // namespace rocksdb