mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 05:32:52 +00:00
62 lines
2.1 KiB
C++
62 lines
2.1 KiB
C++
#include <TableFunctions/ITableFunction.h>
|
|
#include <TableFunctions/TableFunctionZeros.h>
|
|
#include <TableFunctions/TableFunctionFactory.h>
|
|
#include <Parsers/ASTFunction.h>
|
|
#include <Parsers/ASTLiteral.h>
|
|
#include <Storages/System/StorageSystemZeros.h>
|
|
#include <DataTypes/DataTypesNumber.h>
|
|
#include <Interpreters/evaluateConstantExpression.h>
|
|
#include <Interpreters/Context.h>
|
|
#include "registerTableFunctions.h"
|
|
|
|
|
|
namespace DB
|
|
{
|
|
|
|
namespace ErrorCodes
|
|
{
|
|
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
|
|
}
|
|
|
|
|
|
template <bool multithreaded>
|
|
ColumnsDescription TableFunctionZeros<multithreaded>::getActualTableStructure(const Context & /*context*/) const
|
|
{
|
|
/// NOTE: https://bugs.llvm.org/show_bug.cgi?id=47418
|
|
return ColumnsDescription{{{"zero", std::make_shared<DataTypeUInt8>()}}};
|
|
}
|
|
|
|
template <bool multithreaded>
|
|
StoragePtr TableFunctionZeros<multithreaded>::executeImpl(const ASTPtr & ast_function, const Context & context, const std::string & table_name, ColumnsDescription /*cached_columns*/) const
|
|
{
|
|
if (const auto * function = ast_function->as<ASTFunction>())
|
|
{
|
|
auto arguments = function->arguments->children;
|
|
|
|
if (arguments.size() != 1)
|
|
throw Exception("Table function '" + getName() + "' requires 'length'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
|
|
|
|
|
|
UInt64 length = evaluateArgument(context, arguments[0]);
|
|
|
|
auto res = StorageSystemZeros::create(StorageID(getDatabaseName(), table_name), multithreaded, length);
|
|
res->startup();
|
|
return res;
|
|
}
|
|
throw Exception("Table function '" + getName() + "' requires 'limit'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
|
|
}
|
|
|
|
void registerTableFunctionZeros(TableFunctionFactory & factory)
|
|
{
|
|
factory.registerFunction<TableFunctionZeros<true>>();
|
|
factory.registerFunction<TableFunctionZeros<false>>();
|
|
}
|
|
|
|
template <bool multithreaded>
|
|
UInt64 TableFunctionZeros<multithreaded>::evaluateArgument(const Context & context, ASTPtr & argument) const
|
|
{
|
|
return evaluateConstantExpressionOrIdentifierAsLiteral(argument, context)->as<ASTLiteral &>().value.safeGet<UInt64>();
|
|
}
|
|
|
|
}
|