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113 lines
3.3 KiB
113 lines
3.3 KiB
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#ifndef STORAGE_LEVELDB_DB_VERSION_EDIT_H_
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#define STORAGE_LEVELDB_DB_VERSION_EDIT_H_
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#include <set>
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#include <utility>
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#include <vector>
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#include "db/dbformat.h"
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namespace leveldb {
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class VersionSet;
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struct FileMetaData {
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FileMetaData() : refs(0), allowed_seeks(1 << 30), file_size(0),
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smallest_deadtime(UINT64_MAX),largest_deadtime(UINT64_MAX) {}
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int refs;
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int allowed_seeks; // Seeks allowed until compaction
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uint64_t number;
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uint64_t file_size; // File size in bytes
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InternalKey smallest; // Smallest internal key served by table
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InternalKey largest; // Largest internal key served by table
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//在FileMetaData中，使用Uint64MAX作为没有生存期的标志（表示生存期无限长）
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uint64_t smallest_deadtime; //smallest deadtime
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uint64_t largest_deadtime; //largest deadtime
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};
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class VersionEdit {
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public:
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VersionEdit() { Clear(); }
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~VersionEdit() = default;
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void Clear();
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void SetComparatorName(const Slice& name) {
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has_comparator_ = true;
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comparator_ = name.ToString();
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}
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void SetLogNumber(uint64_t num) {
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has_log_number_ = true;
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log_number_ = num;
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}
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void SetPrevLogNumber(uint64_t num) {
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has_prev_log_number_ = true;
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prev_log_number_ = num;
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}
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void SetNextFile(uint64_t num) {
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has_next_file_number_ = true;
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next_file_number_ = num;
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}
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void SetLastSequence(SequenceNumber seq) {
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has_last_sequence_ = true;
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last_sequence_ = seq;
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}
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void SetCompactPointer(int level, const InternalKey& key) {
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compact_pointers_.push_back(std::make_pair(level, key));
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}
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// Add the specified file at the specified number.
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// REQUIRES: This version has not been saved (see VersionSet::SaveTo)
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// REQUIRES: "smallest" and "largest" are smallest and largest keys in file
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void AddFile(int level, uint64_t file, uint64_t file_size,
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const InternalKey& smallest, const InternalKey& largest,
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uint64_t smallest_deadtime = UINT64_MAX, uint64_t largest_deadtime = UINT64_MAX) {
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FileMetaData f;
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f.number = file;
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f.file_size = file_size;
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f.smallest = smallest;
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f.largest = largest;
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f.smallest_deadtime = smallest_deadtime;
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f.largest_deadtime = largest_deadtime;
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new_files_.push_back(std::make_pair(level, f));
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}
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// Delete the specified "file" from the specified "level".
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void RemoveFile(int level, uint64_t file) {
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deleted_files_.insert(std::make_pair(level, file));
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}
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void EncodeTo(std::string* dst) const;
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Status DecodeFrom(const Slice& src);
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std::string DebugString() const;
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private:
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friend class VersionSet;
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typedef std::set<std::pair<int, uint64_t>> DeletedFileSet;
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std::string comparator_;
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uint64_t log_number_;
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uint64_t prev_log_number_;
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uint64_t next_file_number_;
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SequenceNumber last_sequence_;
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bool has_comparator_;
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bool has_log_number_;
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bool has_prev_log_number_;
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bool has_next_file_number_;
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bool has_last_sequence_;
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std::vector<std::pair<int, InternalKey>> compact_pointers_;
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DeletedFileSet deleted_files_;
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std::vector<std::pair<int, FileMetaData>> new_files_;
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};
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_DB_VERSION_EDIT_H_
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