sync/src/wal/WalWriter.cpp at main · vixcpp/sync · GitHub

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
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
/**
 *
 *  @file WalWriter.cpp
 *  @author Gaspard Kirira
 *
 *  Copyright 2025, Gaspard Kirira.  All rights reserved.
 *  https://github.com/vixcpp/vix
 *  Use of this source code is governed by a MIT license
 *  that can be found in the License file.
 *
 *  Vix.cpp
 *
 */
#include <vix/sync/wal/WalWriter.hpp>

#include <stdexcept>

namespace vix::sync::wal
{

  static constexpr std::uint32_t kMagic = 0x56495857; // 'VIXW'
  static constexpr std::uint16_t kVersion = 1;

  WalWriter::WalWriter(Config cfg) : cfg_(std::move(cfg)) { open_(); }
  WalWriter::~WalWriter() { flush(); }

  void WalWriter::open_()
  {
    std::filesystem::create_directories(cfg_.file_path.parent_path());
    out_.open(cfg_.file_path, std::ios::binary | std::ios::app);
    if (!out_)
      throw std::runtime_error("WalWriter: cannot open file");
  }

  std::int64_t WalWriter::tell_()
  {
    return static_cast<std::int64_t>(out_.tellp());
  }

  std::int64_t WalWriter::append(const WalRecord &r)
  {
    if (!out_)
      open_();

    const auto offset = tell_();

    const std::uint32_t id_len = static_cast<std::uint32_t>(r.id.size());
    const std::uint32_t payload_len = static_cast<std::uint32_t>(r.payload.size());
    const std::uint32_t error_len = static_cast<std::uint32_t>(r.error.size());

    // header
    out_.write(reinterpret_cast<const char *>(&kMagic), sizeof(kMagic));
    out_.write(reinterpret_cast<const char *>(&kVersion), sizeof(kVersion));

    const std::uint8_t type = static_cast<std::uint8_t>(r.type);
    out_.write(reinterpret_cast<const char *>(&type), sizeof(type));

    const std::uint8_t reserved = 0;
    out_.write(reinterpret_cast<const char *>(&reserved), sizeof(reserved));

    out_.write(reinterpret_cast<const char *>(&r.ts_ms), sizeof(r.ts_ms));
    out_.write(reinterpret_cast<const char *>(&id_len), sizeof(id_len));
    out_.write(reinterpret_cast<const char *>(&payload_len), sizeof(payload_len));
    out_.write(reinterpret_cast<const char *>(&error_len), sizeof(error_len));
    out_.write(reinterpret_cast<const char *>(&r.next_retry_at_ms), sizeof(r.next_retry_at_ms));

    // body
    if (id_len)
      out_.write(r.id.data(), id_len);
    if (payload_len)
      out_.write(reinterpret_cast<const char *>(r.payload.data()), payload_len);
    if (error_len)
      out_.write(r.error.data(), error_len);

    flush();
    return offset;
  }

  void WalWriter::flush()
  {
    if (!out_)
      return;
    out_.flush();
  }

} // namespace vix::sync::wal