ClickHouse/dbms/src/Parsers/ASTQueryWithOnCluster.h
2019-01-04 15:10:00 +03:00

58 lines
1.6 KiB
C++

#pragma once
#include <Parsers/IAST.h>
#include <Parsers/IParser.h>
namespace DB
{
/// TODO: Quite messy.
class ASTQueryWithOnCluster
{
public:
using Pos = IParser::Pos;
/// Should be parsed from ON CLUSTER <cluster> clause
String cluster;
/// new_database should be used by queries that refer to default db
/// and default_database is specified for remote server
virtual ASTPtr getRewrittenASTWithoutOnCluster(const std::string & new_database = {}) const = 0;
/// Returns a query prepared for execution on remote server
std::string getRewrittenQueryWithoutOnCluster(const std::string & new_database = {}) const;
void formatOnCluster(const IAST::FormatSettings & settings) const;
/// Parses " CLUSTER [cluster|'cluster'] " clause
static bool parse(Pos & pos, std::string & cluster_str, Expected & expected);
virtual ~ASTQueryWithOnCluster() = default;
ASTQueryWithOnCluster() = default;
ASTQueryWithOnCluster(const ASTQueryWithOnCluster &) = default;
ASTQueryWithOnCluster & operator=(const ASTQueryWithOnCluster &) = default;
protected:
template <typename T>
static ASTPtr removeOnCluster(ASTPtr query_ptr, const std::string & new_database)
{
T & query = static_cast<T &>(*query_ptr);
query.cluster.clear();
if (query.database.empty())
query.database = new_database;
return query_ptr;
}
template <typename T>
static ASTPtr removeOnCluster(ASTPtr query_ptr)
{
T & query = static_cast<T &>(*query_ptr);
query.cluster.clear();
return query_ptr;
}
};
}