ClickHouse/src/Parsers/ASTColumnsMatcher.h
2022-04-20 01:22:04 +08:00

54 lines
1.3 KiB
C++

#pragma once
#include <Parsers/IAST.h>
namespace re2
{
class RE2;
}
namespace DB
{
class WriteBuffer;
/** SELECT COLUMNS('regexp') is expanded to multiple columns like * (asterisk).
* Optional transformers can be attached to further manipulate these expanded columns.
*/
class ASTColumnsRegexpMatcher : public IAST
{
public:
String getID(char) const override { return "ColumnsRegexpMatcher"; }
ASTPtr clone() const override;
void appendColumnName(WriteBuffer & ostr) const override;
void setPattern(String pattern);
bool isColumnMatching(const String & column_name) const;
void updateTreeHashImpl(SipHash & hash_state) const override;
protected:
void formatImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
private:
std::shared_ptr<re2::RE2> column_matcher;
String original_pattern;
};
/// Same as the above but use a list of column names to do matching.
class ASTColumnsListMatcher : public IAST
{
public:
String getID(char) const override { return "ColumnsListMatcher"; }
ASTPtr clone() const override;
void appendColumnName(WriteBuffer & ostr) const override;
void updateTreeHashImpl(SipHash & hash_state) const override;
ASTPtr column_list;
protected:
void formatImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
};
}