tdlight/tddb/td/db/SeqKeyValue.h
2023-07-27 13:58:20 +03:00

105 lines
2.2 KiB
C++

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/FlatHashMap.h"
#include "td/utils/Slice.h"
namespace td {
class SeqKeyValue {
public:
using SeqNo = uint64;
SeqKeyValue() = default;
SeqKeyValue(SeqKeyValue &&) = default;
SeqKeyValue &operator=(SeqKeyValue &&) = default;
SeqKeyValue(const SeqKeyValue &) = delete;
SeqKeyValue &operator=(const SeqKeyValue &) = delete;
~SeqKeyValue() = default;
SeqNo set(Slice key, Slice value) {
CHECK(!key.empty());
auto it_ok = map_.emplace(key.str(), value.str());
if (!it_ok.second) {
if (it_ok.first->second == value) {
return 0;
}
it_ok.first->second = value.str();
}
return next_seq_no();
}
SeqNo erase(const string &key) {
auto it = map_.find(key);
if (it == map_.end()) {
return 0;
}
map_.erase(it);
return next_seq_no();
}
SeqNo erase_batch(vector<string> keys) {
size_t count = 0;
for (auto &key : keys) {
auto it = map_.find(key);
if (it != map_.end()) {
map_.erase(it);
count++;
}
}
if (count == 0) {
return 0;
}
SeqNo result = current_id_ + 1;
current_id_ += count;
return result;
}
SeqNo seq_no() const {
return current_id_ + 1;
}
string get(const string &key) const {
auto it = map_.find(key);
if (it == map_.end()) {
return string();
}
return it->second;
}
bool isset(const string &key) const {
auto it = map_.find(key);
if (it == map_.end()) {
return false;
}
return true;
}
size_t size() const {
return map_.size();
}
FlatHashMap<string, string> get_all() const {
FlatHashMap<string, string> result;
result.reserve(map_.size());
for (auto &it : map_) {
result.emplace(it.first, it.second);
}
return result;
}
private:
FlatHashMap<string, string> map_;
SeqNo current_id_ = 0;
SeqNo next_seq_no() {
return ++current_id_;
}
};
} // namespace td