ClickHouse/dbms/src/Storages/StorageFile.h
2017-12-28 07:39:19 +03:00

97 lines
2.5 KiB
C++

#pragma once
#include <Storages/IStorage.h>
#include <Poco/File.h>
#include <Poco/Path.h>
#include <common/logger_useful.h>
#include <atomic>
#include <shared_mutex>
#include <ext/shared_ptr_helper.h>
namespace DB
{
class StorageFileBlockInputStream;
class StorageFileBlockOutputStream;
class StorageFile : public ext::shared_ptr_helper<StorageFile>, public IStorage
{
public:
std::string getName() const override
{
return "File";
}
std::string getTableName() const override
{
return table_name;
}
const NamesAndTypesList & getColumnsListImpl() const override
{
return columns;
}
BlockInputStreams read(
const Names & column_names,
const SelectQueryInfo & query_info,
const Context & context,
QueryProcessingStage::Enum & processed_stage,
size_t max_block_size,
unsigned num_streams) override;
BlockOutputStreamPtr write(
const ASTPtr & query,
const Settings & settings) override;
void drop() override;
void rename(const String & new_path_to_db, const String & new_database_name, const String & new_table_name) override;
protected:
friend class StorageFileBlockInputStream;
friend class StorageFileBlockOutputStream;
/** there are three options (ordered by priority):
- use specified file descriptor if (fd >= 0)
- use specified table_path if it isn't empty
- create own tabale inside data/db/table/
*/
StorageFile(
const std::string & table_path_,
int table_fd_,
const std::string & db_dir_path,
const std::string & table_name_,
const std::string & format_name_,
const NamesAndTypesList & columns_,
const NamesAndTypesList & materialized_columns_,
const NamesAndTypesList & alias_columns_,
const ColumnDefaults & column_defaults_,
Context & context_);
private:
std::string table_name;
std::string format_name;
NamesAndTypesList columns;
Context & context_global;
std::string path;
int table_fd = -1;
bool is_db_table = true; /// Table is stored in real database, not user's file
bool use_table_fd = false; /// Use table_fd insted of path
std::atomic<bool> table_fd_was_used{false}; /// To detect repeating reads from stdin
off_t table_fd_init_offset = -1; /// Initial position of fd, used for repeating reads
mutable std::shared_mutex rwlock;
Logger * log = &Logger::get("StorageFile");
};
}