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tdlib-fork/tddb/td/db/SqliteKeyValue.h

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018
//
// 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/db/SqliteDb.h"
#include "td/db/SqliteStatement.h"
#include "td/utils/logging.h"
#include "td/utils/Slice.h"
#include "td/utils/Status.h"
#include <unordered_map>
namespace td {
class SqliteKeyValue {
public:
static Status drop(SqliteDb &connection, Slice table_name) TD_WARN_UNUSED_RESULT {
return connection.exec(PSLICE() << "DROP TABLE IF EXISTS " << table_name);
}
static Status init(SqliteDb &connection, Slice table_name) TD_WARN_UNUSED_RESULT {
return connection.exec(PSLICE() << "CREATE TABLE IF NOT EXISTS " << table_name << " (k BLOB PRIMARY KEY, v BLOB)");
}
using SeqNo = uint64;
bool empty() const {
return db_.empty();
}
Result<bool> init(string path) TD_WARN_UNUSED_RESULT;
Status init_with_connection(SqliteDb connection, string table_name) TD_WARN_UNUSED_RESULT;
Result<bool> try_regenerate_index() TD_WARN_UNUSED_RESULT {
return false;
}
void close() {
*this = SqliteKeyValue();
}
Status drop();
SeqNo set(Slice key, Slice value);
string get(Slice key);
SeqNo erase(Slice key);
Status begin_transaction() TD_WARN_UNUSED_RESULT {
return db_.begin_transaction();
}
Status commit_transaction() TD_WARN_UNUSED_RESULT {
return db_.commit_transaction();
}
void erase_by_prefix(Slice prefix);
std::unordered_map<string, string> get_all() {
std::unordered_map<string, string> res;
get_by_prefix("", [&](Slice key, Slice value) { res.emplace(key.str(), value.str()); });
return res;
}
template <class CallbackT>
void get_by_prefix(Slice prefix, CallbackT &&callback) {
string next;
if (!prefix.empty()) {
next = next_prefix(prefix);
}
get_by_range(prefix, next, callback);
}
template <class CallbackT>
void get_by_range(Slice from, Slice till, CallbackT &&callback) {
SqliteStatement *stmt = nullptr;
if (from.empty()) {
stmt = &get_all_stmt_;
} else {
if (till.empty()) {
stmt = &get_by_prefix_rare_stmt_;
stmt->bind_blob(1, till).ensure();
} else {
stmt = &get_by_prefix_stmt_;
stmt->bind_blob(1, from).ensure();
stmt->bind_blob(2, till).ensure();
}
}
auto guard = stmt->guard();
stmt->step().ensure();
while (stmt->has_row()) {
callback(stmt->view_blob(0), stmt->view_blob(1));
stmt->step().ensure();
}
}
private:
string path_;
string table_name_;
SqliteDb db_;
SqliteStatement get_stmt_;
SqliteStatement set_stmt_;
SqliteStatement erase_stmt_;
SqliteStatement get_all_stmt_;
SqliteStatement erase_by_prefix_stmt_;
SqliteStatement erase_by_prefix_rare_stmt_;
SqliteStatement get_by_prefix_stmt_;
SqliteStatement get_by_prefix_rare_stmt_;
string next_prefix(Slice prefix);
};
} // namespace td