tdlight/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/ScopeGuard.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 kv_name) TD_WARN_UNUSED_RESULT {
return connection.exec(PSLICE() << "DROP TABLE IF EXISTS " << kv_name);
}
static Status init(SqliteDb &connection, Slice kv_name) TD_WARN_UNUSED_RESULT {
return connection.exec(PSLICE() << "CREATE TABLE IF NOT EXISTS " << kv_name << " (k BLOB PRIMARY KEY, v BLOB)");
}
using SeqNo = uint64;
Result<bool> init(string name) TD_WARN_UNUSED_RESULT {
name_ = std::move(name);
bool is_created = false;
SqliteDb db;
TRY_STATUS(db.init(name, &is_created));
TRY_STATUS(db.exec("PRAGMA encoding=\"UTF-8\""));
TRY_STATUS(db.exec("PRAGMA synchronous=NORMAL"));
TRY_STATUS(db.exec("PRAGMA journal_mode=WAL"));
TRY_STATUS(db.exec("PRAGMA temp_store=MEMORY"));
TRY_STATUS(init_with_connection(std::move(db), "KV"));
return is_created;
}
Status init_with_connection(SqliteDb connection, string kv_name) {
db_ = std::move(connection);
kv_name_ = std::move(kv_name);
TRY_STATUS(init(db_, kv_name_));
TRY_STATUS(db_.exec(PSLICE() << "CREATE TABLE IF NOT EXISTS " << kv_name_ << " (k BLOB PRIMARY KEY, v BLOB)"));
TRY_RESULT(set_stmt, db_.get_statement(PSLICE() << "REPLACE INTO " << kv_name_ << " (k, v) VALUES (?1, ?2)"));
set_stmt_ = std::move(set_stmt);
TRY_RESULT(get_stmt, db_.get_statement(PSLICE() << "SELECT v FROM " << kv_name_ << " WHERE k = ?1"));
get_stmt_ = std::move(get_stmt);
TRY_RESULT(erase_stmt, db_.get_statement(PSLICE() << "DELETE FROM " << kv_name_ << " WHERE k = ?1"));
erase_stmt_ = std::move(erase_stmt);
TRY_RESULT(get_all_stmt, db_.get_statement(PSLICE() << "SELECT k, v FROM " << kv_name_ << ""));
TRY_RESULT(erase_by_prefix_stmt,
db_.get_statement(PSLICE() << "DELETE FROM " << kv_name_ << " WHERE ?1 <= k AND k < ?2"));
erase_by_prefix_stmt_ = std::move(erase_by_prefix_stmt);
TRY_RESULT(erase_by_prefix_rare_stmt,
db_.get_statement(PSLICE() << "DELETE FROM " << kv_name_ << " WHERE ?1 <= k"));
erase_by_prefix_rare_stmt_ = std::move(erase_by_prefix_rare_stmt);
TRY_RESULT(get_by_prefix_stmt,
db_.get_statement(PSLICE() << "SELECT k, v FROM " << kv_name_ << " WHERE ?1 <= k AND k < ?2"));
get_by_prefix_stmt_ = std::move(get_by_prefix_stmt);
TRY_RESULT(get_by_prefix_rare_stmt,
db_.get_statement(PSLICE() << "SELECT k, v FROM " << kv_name_ << " WHERE ?1 <= k"));
get_by_prefix_rare_stmt_ = std::move(get_by_prefix_rare_stmt);
get_all_stmt_ = std::move(get_all_stmt);
return Status::OK();
}
Result<bool> try_regenerate_index() TD_WARN_UNUSED_RESULT {
return false;
}
void close() {
clear();
}
void close_silent() {
clear();
}
static Status destroy(Slice name) {
return SqliteDb::destroy(name);
}
void close_and_destroy() {
db_.exec(PSLICE() << "DROP TABLE IF EXISTS " << kv_name_).ensure();
auto name = std::move(name_);
clear();
if (!name.empty()) {
SqliteDb::destroy(name).ignore();
}
}
SeqNo set(Slice key, Slice value) {
set_stmt_.bind_blob(1, key).ensure();
set_stmt_.bind_blob(2, value).ensure();
set_stmt_.step().ensure();
set_stmt_.reset();
return 0;
}
SeqNo erase(Slice key) {
erase_stmt_.bind_blob(1, key).ensure();
erase_stmt_.step().ensure();
erase_stmt_.reset();
return 0;
}
string get(Slice key) {
SCOPE_EXIT {
get_stmt_.reset();
};
get_stmt_.bind_blob(1, key).ensure();
get_stmt_.step().ensure();
if (!get_stmt_.has_row()) {
return "";
}
auto data = get_stmt_.view_blob(0).str();
get_stmt_.step().ignore();
return data;
}
Status begin_transaction() {
return db_.begin_transaction();
}
Status commit_transaction() {
return db_.commit_transaction();
}
void erase_by_prefix(Slice prefix) {
auto next = next_prefix(prefix);
if (next.empty()) {
SCOPE_EXIT {
erase_by_prefix_rare_stmt_.reset();
};
erase_by_prefix_rare_stmt_.bind_blob(1, prefix).ensure();
erase_by_prefix_rare_stmt_.step().ensure();
} else {
SCOPE_EXIT {
erase_by_prefix_stmt_.reset();
};
erase_by_prefix_stmt_.bind_blob(1, prefix).ensure();
erase_by_prefix_stmt_.bind_blob(2, next).ensure();
erase_by_prefix_stmt_.step().ensure();
}
};
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();
}
}
void clear() {
*this = SqliteKeyValue();
}
private:
string name_; // deprecated
string kv_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) {
string next = prefix.str();
size_t pos = next.size();
while (pos) {
pos--;
auto value = static_cast<uint8>(next[pos]);
value++;
next[pos] = static_cast<char>(value);
if (value != 0) {
return next;
}
}
return string{};
}
};
} // namespace td