ClickHouse/src/TableFunctions/TableFunctionViewIfPermitted.h
2022-07-15 15:44:29 +02:00

36 lines
1.1 KiB
C++

#pragma once
#include <TableFunctions/ITableFunction.h>
#include <Parsers/ASTCreateQuery.h>
#include <base/types.h>
namespace DB
{
/* viewIfPermitted(query ELSE null('structure'))
* Works as "view(query)" if the current user has the permissions required to execute "query"; works as "null('structure')" otherwise.
*/
class TableFunctionViewIfPermitted : public ITableFunction
{
public:
static constexpr auto name = "viewIfPermitted";
std::string getName() const override { return name; }
const ASTSelectWithUnionQuery & getSelectQuery() const;
private:
StoragePtr executeImpl(const ASTPtr & ast_function, ContextPtr context, const String & table_name, ColumnsDescription cached_columns) const override;
const char * getStorageTypeName() const override { return "ViewIfPermitted"; }
void parseArguments(const ASTPtr & ast_function, ContextPtr context) override;
ColumnsDescription getActualTableStructure(ContextPtr context) const override;
bool isPermitted(const ContextPtr & context, const ColumnsDescription & else_columns) const;
ASTCreateQuery create;
ASTPtr else_ast;
TableFunctionPtr else_table_function;
};
}