ClickHouse/src/Functions/flattenTuple.cpp
2022-03-28 19:32:12 +00:00

69 lines
2.2 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/ObjectUtils.h>
#include <Columns/ColumnTuple.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
class FunctionFlattenTuple : public IFunction
{
public:
static constexpr auto name = "flattenTuple";
static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionFlattenTuple>(); }
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 1; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo &) const override { return true; }
bool useDefaultImplementationForConstants() const override { return true; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
const auto & type = arguments[0];
const auto * type_tuple = checkAndGetDataType<DataTypeTuple>(type.get());
if (!type_tuple || !type_tuple->haveExplicitNames())
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Argument for function '{}' must be Named Tuple. Got '{}'",
getName(), type->getName());
auto [paths, types] = flattenTuple(type);
Names names;
names.reserve(paths.size());
for (const auto & path : paths)
names.push_back(path.getPath());
return std::make_shared<DataTypeTuple>(types, names);
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
{
auto column = arguments.at(0).column;
if (!checkAndGetColumn<ColumnTuple>(column.get()))
throw Exception(ErrorCodes::ILLEGAL_COLUMN,
"Illegal column {} of first argument of function {}. Expected ColumnTuple",
column->getName(), getName());
return flattenTuple(column);
}
};
}
void registerFunctionFlattenTuple(FunctionFactory & factory)
{
factory.registerFunction<FunctionFlattenTuple>();
}
}