summaryrefslogtreecommitdiff
path: root/db/log_writer.h
blob: c0a21147ee9cd7de674de47315b121050108628c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#ifndef STORAGE_LEVELDB_DB_LOG_WRITER_H_
#define STORAGE_LEVELDB_DB_LOG_WRITER_H_

#include <stdint.h>

#include "db/log_format.h"
#include "leveldb/slice.h"
#include "leveldb/status.h"

namespace leveldb {

class WritableFile;

namespace log {

class Writer {
 public:
  // Create a writer that will append data to "*dest".
  // "*dest" must be initially empty.
  // "*dest" must remain live while this Writer is in use.
  explicit Writer(WritableFile* dest);

  // Create a writer that will append data to "*dest".
  // "*dest" must have initial length "dest_length".
  // "*dest" must remain live while this Writer is in use.
  Writer(WritableFile* dest, uint64_t dest_length);

  Writer(const Writer&) = delete;
  Writer& operator=(const Writer&) = delete;

  ~Writer();

  Status AddRecord(const Slice& slice);

 private:
  Status EmitPhysicalRecord(RecordType type, const char* ptr, size_t length);

  WritableFile* dest_;
  int block_offset_;  // Current offset in block

  // crc32c values for all supported record types.  These are
  // pre-computed to reduce the overhead of computing the crc of the
  // record type stored in the header.
  uint32_t type_crc_[kMaxRecordType + 1];
};

}  // namespace log
}  // namespace leveldb

#endif  // STORAGE_LEVELDB_DB_LOG_WRITER_H_