ClickHouse/dbms/Interpreters/QueryNormalizer.h
Ivan 97f2a2213e
Move all folders inside /dbms one level up (#9974)
* Move some code outside dbms/src folder
* Fix paths
2020-04-02 02:51:21 +03:00

76 lines
1.8 KiB
C++

#pragma once
#include <map>
#include <Parsers/IAST.h>
#include <Interpreters/Aliases.h>
namespace DB
{
class ASTSelectQuery;
class ASTIdentifier;
struct ASTTablesInSelectQueryElement;
class Context;
class QueryNormalizer
{
/// Extracts settings, mostly to show which are used and which are not.
struct ExtractedSettings
{
const UInt64 max_ast_depth;
const UInt64 max_expanded_ast_elements;
template <typename T>
ExtractedSettings(const T & settings)
: max_ast_depth(settings.max_ast_depth),
max_expanded_ast_elements(settings.max_expanded_ast_elements)
{}
};
public:
struct Data
{
using SetOfASTs = std::set<const IAST *>;
using MapOfASTs = std::map<ASTPtr, ASTPtr>;
const Aliases & aliases;
const ExtractedSettings settings;
/// tmp data
size_t level;
MapOfASTs finished_asts; /// already processed vertices (and by what they replaced)
SetOfASTs current_asts; /// vertices in the current call stack of this method
std::string current_alias; /// the alias referencing to the ancestor of ast (the deepest ancestor with aliases)
Data(const Aliases & aliases_, ExtractedSettings && settings_)
: aliases(aliases_)
, settings(settings_)
, level(0)
{}
};
QueryNormalizer(Data & data)
: visitor_data(data)
{}
void visit(ASTPtr & ast)
{
visit(ast, visitor_data);
}
private:
Data & visitor_data;
static void visit(ASTPtr & ast, Data & data);
static void visit(ASTIdentifier &, ASTPtr &, Data &);
static void visit(ASTTablesInSelectQueryElement &, const ASTPtr &, Data &);
static void visit(ASTSelectQuery &, const ASTPtr &, Data &);
static void visitChildren(const ASTPtr &, Data & data);
};
}