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#ifndef STORAGE_LEVELDB_DB_VERSION_EDIT_H_
6#define STORAGE_LEVELDB_DB_VERSION_EDIT_H_
7
8#include <set>
9#include <utility>
10#include <vector>
11
12#include "db/dbformat.h"
13
14namespace leveldb {
15
16class VersionSet;
17
18struct FileMetaData {
19  FileMetaData() : refs(0), allowed_seeks(1 << 30), file_size(0) {}
20
21  int refs;
22  int allowed_seeks;  // Seeks allowed until compaction
23  uint64_t number;
24  uint64_t file_size;    // File size in bytes
25  InternalKey smallest;  // Smallest internal key served by table
26  InternalKey largest;   // Largest internal key served by table
27};
28
29class VersionEdit {
30 public:
31  VersionEdit() { Clear(); }
32  ~VersionEdit() = default;
33
34  void Clear();
35
36  void SetComparatorName(const Slice& name) {
37    has_comparator_ = true;
38    comparator_ = name.ToString();
39  }
40  void SetLogNumber(uint64_t num) {
41    has_log_number_ = true;
42    log_number_ = num;
43  }
44  void SetPrevLogNumber(uint64_t num) {
45    has_prev_log_number_ = true;
46    prev_log_number_ = num;
47  }
48  void SetNextFile(uint64_t num) {
49    has_next_file_number_ = true;
50    next_file_number_ = num;
51  }
52  void SetLastSequence(SequenceNumber seq) {
53    has_last_sequence_ = true;
54    last_sequence_ = seq;
55  }
56  void SetCompactPointer(int level, const InternalKey& key) {
57    compact_pointers_.push_back(std::make_pair(level, key));
58  }
59
60  // Add the specified file at the specified number.
61  // REQUIRES: This version has not been saved (see VersionSet::SaveTo)
62  // REQUIRES: "smallest" and "largest" are smallest and largest keys in file
63  void AddFile(int level, uint64_t file, uint64_t file_size,
64               const InternalKey& smallest, const InternalKey& largest) {
65    FileMetaData f;
66    f.number = file;
67    f.file_size = file_size;
68    f.smallest = smallest;
69    f.largest = largest;
70    new_files_.push_back(std::make_pair(level, f));
71  }
72
73  // Delete the specified "file" from the specified "level".
74  void DeleteFile(int level, uint64_t file) {
75    deleted_files_.insert(std::make_pair(level, file));
76  }
77
78  void EncodeTo(std::string* dst) const;
79  Status DecodeFrom(const Slice& src);
80
81  std::string DebugString() const;
82
83 private:
84  friend class VersionSet;
85
86  typedef std::set<std::pair<int, uint64_t>> DeletedFileSet;
87
88  std::string comparator_;
89  uint64_t log_number_;
90  uint64_t prev_log_number_;
91  uint64_t next_file_number_;
92  SequenceNumber last_sequence_;
93  bool has_comparator_;
94  bool has_log_number_;
95  bool has_prev_log_number_;
96  bool has_next_file_number_;
97  bool has_last_sequence_;
98
99  std::vector<std::pair<int, InternalKey>> compact_pointers_;
100  DeletedFileSet deleted_files_;
101  std::vector<std::pair<int, FileMetaData>> new_files_;
102};
103
104}  // namespace leveldb
105
106#endif  // STORAGE_LEVELDB_DB_VERSION_EDIT_H_
107