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257 行
6.6 KiB
257 行
6.6 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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#include "db/version_edit.h"
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#include "db/version_set.h"
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#include "util/coding.h"
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namespace leveldb {
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// Tag numbers for serialized VersionEdit. These numbers are written to
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// disk and should not be changed.
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enum Tag {
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kComparator = 1,
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kLogNumber = 2,
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kNextFileNumber = 3,
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kLastSequence = 4,
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kCompactPointer = 5,
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kDeletedFile = 6,
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kNewFile = 7,
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// 8 was used for large value refs
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kPrevLogNumber = 9
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};
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void VersionEdit::Clear() {
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comparator_.clear();
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log_number_ = 0;
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prev_log_number_ = 0;
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last_sequence_ = 0;
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next_file_number_ = 0;
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has_comparator_ = false;
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has_log_number_ = false;
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has_prev_log_number_ = false;
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has_next_file_number_ = false;
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has_last_sequence_ = false;
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deleted_files_.clear();
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new_files_.clear();
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}
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void VersionEdit::EncodeTo(std::string* dst) const {
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if (has_comparator_) {
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PutVarint32(dst, kComparator);
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PutLengthPrefixedSlice(dst, comparator_);
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}
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if (has_log_number_) {
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PutVarint32(dst, kLogNumber);
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PutVarint64(dst, log_number_);
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}
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if (has_prev_log_number_) {
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PutVarint32(dst, kPrevLogNumber);
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PutVarint64(dst, prev_log_number_);
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}
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if (has_next_file_number_) {
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PutVarint32(dst, kNextFileNumber);
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PutVarint64(dst, next_file_number_);
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}
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if (has_last_sequence_) {
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PutVarint32(dst, kLastSequence);
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PutVarint64(dst, last_sequence_);
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}
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for (size_t i = 0; i < compact_pointers_.size(); i++) {
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PutVarint32(dst, kCompactPointer);
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PutVarint32(dst, compact_pointers_[i].first); // level
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PutLengthPrefixedSlice(dst, compact_pointers_[i].second.Encode());
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}
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for (const auto& deleted_file_kvp : deleted_files_) {
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PutVarint32(dst, kDeletedFile);
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PutVarint32(dst, deleted_file_kvp.first); // level
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PutVarint64(dst, deleted_file_kvp.second); // file number
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}
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for (size_t i = 0; i < new_files_.size(); i++) {
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const FileMetaData& f = new_files_[i].second;
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PutVarint32(dst, kNewFile);
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PutVarint32(dst, new_files_[i].first); // level
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PutVarint64(dst, f.number);
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PutVarint64(dst, f.file_size);
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PutLengthPrefixedSlice(dst, f.smallest.Encode());
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PutLengthPrefixedSlice(dst, f.largest.Encode());
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}
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}
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static bool GetInternalKey(Slice* input, InternalKey* dst) {
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Slice str;
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if (GetLengthPrefixedSlice(input, &str)) {
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return dst->DecodeFrom(str);
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} else {
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return false;
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}
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}
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static bool GetLevel(Slice* input, int* level) {
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uint32_t v;
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if (GetVarint32(input, &v) && v < config::kNumLevels) {
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*level = v;
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return true;
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} else {
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return false;
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}
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}
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Status VersionEdit::DecodeFrom(const Slice& src) {
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Clear();
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Slice input = src;
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const char* msg = nullptr;
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uint32_t tag;
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// Temporary storage for parsing
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int level;
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uint64_t number;
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FileMetaData f;
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Slice str;
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InternalKey key;
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while (msg == nullptr && GetVarint32(&input, &tag)) {
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switch (tag) {
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case kComparator:
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if (GetLengthPrefixedSlice(&input, &str)) {
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comparator_ = str.ToString();
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has_comparator_ = true;
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} else {
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msg = "comparator name";
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}
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break;
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case kLogNumber:
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if (GetVarint64(&input, &log_number_)) {
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has_log_number_ = true;
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} else {
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msg = "log number";
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}
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break;
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case kPrevLogNumber:
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if (GetVarint64(&input, &prev_log_number_)) {
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has_prev_log_number_ = true;
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} else {
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msg = "previous log number";
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}
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break;
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case kNextFileNumber:
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if (GetVarint64(&input, &next_file_number_)) {
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has_next_file_number_ = true;
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} else {
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msg = "next file number";
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}
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break;
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case kLastSequence:
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if (GetVarint64(&input, &last_sequence_)) {
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has_last_sequence_ = true;
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} else {
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msg = "last sequence number";
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}
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break;
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case kCompactPointer:
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if (GetLevel(&input, &level) && GetInternalKey(&input, &key)) {
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compact_pointers_.push_back(std::make_pair(level, key));
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} else {
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msg = "compaction pointer";
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}
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break;
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case kDeletedFile:
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if (GetLevel(&input, &level) && GetVarint64(&input, &number)) {
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deleted_files_.insert(std::make_pair(level, number));
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} else {
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msg = "deleted file";
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}
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break;
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case kNewFile:
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if (GetLevel(&input, &level) && GetVarint64(&input, &f.number) &&
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GetVarint64(&input, &f.file_size) &&
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GetInternalKey(&input, &f.smallest) &&
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GetInternalKey(&input, &f.largest)) {
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new_files_.push_back(std::make_pair(level, f));
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} else {
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msg = "new-file entry";
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}
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break;
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default:
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msg = "unknown tag";
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break;
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}
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}
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if (msg == nullptr && !input.empty()) {
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msg = "invalid tag";
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}
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Status result;
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if (msg != nullptr) {
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result = Status::Corruption("VersionEdit", msg);
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}
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return result;
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}
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std::string VersionEdit::DebugString() const {
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std::string r;
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r.append("VersionEdit {");
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if (has_comparator_) {
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r.append("\n Comparator: ");
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r.append(comparator_);
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}
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if (has_log_number_) {
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r.append("\n LogNumber: ");
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AppendNumberTo(&r, log_number_);
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}
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if (has_prev_log_number_) {
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r.append("\n PrevLogNumber: ");
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AppendNumberTo(&r, prev_log_number_);
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}
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if (has_next_file_number_) {
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r.append("\n NextFile: ");
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AppendNumberTo(&r, next_file_number_);
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}
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if (has_last_sequence_) {
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r.append("\n LastSeq: ");
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AppendNumberTo(&r, last_sequence_);
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}
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for (size_t i = 0; i < compact_pointers_.size(); i++) {
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r.append("\n CompactPointer: ");
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AppendNumberTo(&r, compact_pointers_[i].first);
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r.append(" ");
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r.append(compact_pointers_[i].second.DebugString());
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}
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for (const auto& deleted_files_kvp : deleted_files_) {
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r.append("\n RemoveFile: ");
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AppendNumberTo(&r, deleted_files_kvp.first);
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r.append(" ");
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AppendNumberTo(&r, deleted_files_kvp.second);
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}
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for (size_t i = 0; i < new_files_.size(); i++) {
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const FileMetaData& f = new_files_[i].second;
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r.append("\n AddFile: ");
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AppendNumberTo(&r, new_files_[i].first);
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r.append(" ");
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AppendNumberTo(&r, f.number);
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r.append(" ");
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AppendNumberTo(&r, f.file_size);
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r.append(" ");
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r.append(f.smallest.DebugString());
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r.append(" .. ");
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r.append(f.largest.DebugString());
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}
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r.append("\n}\n");
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return r;
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}
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} // namespace leveldb
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