ClickHouse/dbms/src/Storages/StorageFactory.h
2019-08-25 00:20:20 +03:00

81 lines
2.2 KiB
C++

#pragma once
#include <Common/NamePrompter.h>
#include <Parsers/IAST_fwd.h>
#include <Storages/ColumnsDescription.h>
#include <Storages/ConstraintsDescription.h>
#include <Storages/IStorage_fwd.h>
#include <ext/singleton.h>
#include <unordered_map>
namespace DB
{
class Context;
class ASTCreateQuery;
class ASTStorage;
/** Allows to create a table by the name and parameters of the engine.
* In 'columns' Nested data structures must be flattened.
* You should subsequently call IStorage::startup method to work with table.
*/
class StorageFactory : public ext::singleton<StorageFactory>, public IHints<1, StorageFactory>
{
public:
struct Arguments
{
const String & engine_name;
ASTs & engine_args;
ASTStorage * storage_def;
const ASTCreateQuery & query;
const String & data_path;
const String & table_name;
const String & database_name;
Context & local_context;
Context & context;
const ColumnsDescription & columns;
const ConstraintsDescription & constraints;
bool attach;
bool has_force_restore_data_flag;
};
using Creator = std::function<StoragePtr(const Arguments & arguments)>;
StoragePtr get(
ASTCreateQuery & query,
const String & data_path,
const String & table_name,
const String & database_name,
Context & local_context,
Context & context,
const ColumnsDescription & columns,
const ConstraintsDescription & constraints,
bool attach,
bool has_force_restore_data_flag) const;
/// Register a table engine by its name.
/// No locking, you must register all engines before usage of get.
void registerStorage(const std::string & name, Creator creator);
const auto & getAllStorages() const
{
return storages;
}
std::vector<String> getAllRegisteredNames() const override
{
std::vector<String> result;
auto getter = [](const auto & pair) { return pair.first; };
std::transform(storages.begin(), storages.end(), std::back_inserter(result), getter);
return result;
}
private:
using Storages = std::unordered_map<std::string, Creator>;
Storages storages;
};
}