ClickHouse/src/Functions/FunctionHelpers.cpp

#include <Functions/FunctionHelpers.h>
#include <Functions/IFunction.h>
#include <Columns/ColumnTuple.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnFixedString.h>
#include <Columns/ColumnNullable.h>
#include <Columns/ColumnLowCardinality.h>
#include <Common/assert_cast.h>
#include <DataTypes/DataTypeNullable.h>


namespace DB
{

namespace ErrorCodes
{
    extern const int ILLEGAL_COLUMN;
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
    extern const int SIZES_OF_ARRAYS_DONT_MATCH;
    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}

const ColumnConst * checkAndGetColumnConstStringOrFixedString(const IColumn * column)
{
    if (!isColumnConst(*column))
        return {};

    const ColumnConst * res = assert_cast<const ColumnConst *>(column);

    if (checkColumn<ColumnString>(&res->getDataColumn())
        || checkColumn<ColumnFixedString>(&res->getDataColumn()))
        return res;

    return {};
}


Columns convertConstTupleToConstantElements(const ColumnConst & column)
{
    const ColumnTuple & src_tuple = assert_cast<const ColumnTuple &>(column.getDataColumn());
    const auto & src_tuple_columns = src_tuple.getColumns();
    size_t tuple_size = src_tuple_columns.size();
    size_t rows = column.size();

    Columns res(tuple_size);
    for (size_t i = 0; i < tuple_size; ++i)
        res[i] = ColumnConst::create(src_tuple_columns[i], rows);

    return res;
}

ColumnWithTypeAndName columnGetNested(const ColumnWithTypeAndName & col)
{
    if (col.type->isNullable())
    {
        const DataTypePtr & nested_type = static_cast<const DataTypeNullable &>(*col.type).getNestedType();

        if (!col.column)
        {
            return ColumnWithTypeAndName{nullptr, nested_type, col.name};
        }
        else if (const auto * nullable = checkAndGetColumn<ColumnNullable>(*col.column))
        {
            const auto & nested_col = nullable->getNestedColumnPtr();
            return ColumnWithTypeAndName{nested_col, nested_type, col.name};
        }
        else if (const auto * const_column = checkAndGetColumn<ColumnConst>(*col.column))
        {
            const auto * nullable_column = checkAndGetColumn<ColumnNullable>(const_column->getDataColumn());

            ColumnPtr nullable_res;
            if (nullable_column)
            {
                const auto & nested_col = nullable_column->getNestedColumnPtr();
                nullable_res = ColumnConst::create(nested_col, col.column->size());
            }
            else
            {
                nullable_res = makeNullable(col.column);
            }
            return ColumnWithTypeAndName{ nullable_res, nested_type, col.name };
        }
        else
            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column for DataTypeNullable");
    }
    return col;
}

ColumnsWithTypeAndName createBlockWithNestedColumns(const ColumnsWithTypeAndName & columns)
{
    ColumnsWithTypeAndName res;
    for (const auto & col : columns)
        res.emplace_back(columnGetNested(col));

    return res;
}

void validateArgumentType(const IFunction & func, const DataTypes & arguments,
                          size_t argument_index, bool (* validator_func)(const IDataType &),
                          const char * expected_type_description)
{
    if (arguments.size() <= argument_index)
        throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH, "Incorrect number of arguments of function {}",
                        func.getName());

    const auto & argument = arguments[argument_index];
    if (!validator_func(*argument))
        throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT, "Illegal type {} of {} argument of function {} expected {}",
                        argument->getName(), std::to_string(argument_index), func.getName(), expected_type_description);
}

namespace
{
void validateArgumentsImpl(const IFunction & func,
                           const ColumnsWithTypeAndName & arguments,
                           size_t argument_offset,
                           const FunctionArgumentDescriptors & descriptors)
{
    for (size_t i = 0; i < descriptors.size(); ++i)
    {
        const auto argument_index = i + argument_offset;
        if (argument_index >= arguments.size())
        {
            break;
        }

        const auto & arg = arguments[i + argument_offset];
        const auto & descriptor = descriptors[i];
        if (int error_code = descriptor.isValid(arg.type, arg.column); error_code != 0)
            throw Exception(error_code,
                            "Illegal type of argument #{}{} of function {}{}{}",
                            argument_offset + i + 1,    // +1 is for human-friendly 1-based indexing
                            (descriptor.argument_name ? " '" + std::string(descriptor.argument_name) + "'" : String{}),
                            func.getName(),
                            (descriptor.expected_type_description ? String(", expected ") + descriptor.expected_type_description : String{}),
                            (arg.type ? ", got " + arg.type->getName() : String{}));
    }
}

}

int FunctionArgumentDescriptor::isValid(const DataTypePtr & data_type, const ColumnPtr & column) const
{
    if (type_validator_func && (data_type == nullptr || !type_validator_func(*data_type)))
        return ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT;

    if (column_validator_func && (column == nullptr || !column_validator_func(*column)))
        return ErrorCodes::ILLEGAL_COLUMN;

    return 0;
}

void validateFunctionArgumentTypes(const IFunction & func,
                                   const ColumnsWithTypeAndName & arguments,
                                   const FunctionArgumentDescriptors & mandatory_args,
                                   const FunctionArgumentDescriptors & optional_args)
{
    if (arguments.size() < mandatory_args.size() || arguments.size() > mandatory_args.size() + optional_args.size())
    {
        auto join_argument_types = [](const auto & args, const String sep = ", ")
        {
            String result;
            for (const auto & a : args)
            {
                using A = std::decay_t<decltype(a)>;
                if constexpr (std::is_same_v<A, FunctionArgumentDescriptor>)
                {
                    if (a.argument_name)
                        result += "'" + std::string(a.argument_name) + "' : ";
                    if (a.expected_type_description)
                        result += a.expected_type_description;
                }
                else if constexpr (std::is_same_v<A, ColumnWithTypeAndName>)
                    result += a.type->getName();

                result += sep;
            }

            if (!args.empty())
                result.erase(result.end() - sep.length(), result.end());

            return result;
        };

        throw Exception(ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH,
            "Incorrect number of arguments for function {} provided {}{}, expected {}{} ({}{})",
            func.getName(), arguments.size(), (!arguments.empty() ? " (" + join_argument_types(arguments) + ")" : String{}),
            mandatory_args.size(), (!optional_args.empty() ? " to " + std::to_string(mandatory_args.size() + optional_args.size()) : ""),
            join_argument_types(mandatory_args), (!optional_args.empty() ? ", [" + join_argument_types(optional_args) + "]" : ""));
    }

    validateArgumentsImpl(func, arguments, 0, mandatory_args);
    if (!optional_args.empty())
        validateArgumentsImpl(func, arguments, mandatory_args.size(), optional_args);
}

std::pair<std::vector<const IColumn *>, const ColumnArray::Offset *>
checkAndGetNestedArrayOffset(const IColumn ** columns, size_t num_arguments)
{
    assert(num_arguments > 0);
    std::vector<const IColumn *> nested_columns(num_arguments);
    const ColumnArray::Offsets * offsets = nullptr;
    for (size_t i = 0; i < num_arguments; ++i)
    {
        const ColumnArray::Offsets * offsets_i = nullptr;
        if (const ColumnArray * arr = checkAndGetColumn<const ColumnArray>(columns[i]))
        {
            nested_columns[i] = &arr->getData();
            offsets_i = &arr->getOffsets();
        }
        else
            throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} as argument of function", columns[i]->getName());
        if (i == 0)
            offsets = offsets_i;
        else if (*offsets_i != *offsets)
            throw Exception(ErrorCodes::SIZES_OF_ARRAYS_DONT_MATCH, "Lengths of all arrays passed to aggregate function must be equal.");
    }
    return {nested_columns, offsets->data()};
}

bool areTypesEqual(const IDataType & lhs, const IDataType & rhs)
{
    const auto & lhs_name = lhs.getName();
    const auto & rhs_name = rhs.getName();

    return lhs_name == rhs_name;
}

bool areTypesEqual(const DataTypePtr & lhs, const DataTypePtr & rhs)
{
    return areTypesEqual(*lhs, *rhs);
}

ColumnPtr wrapInNullable(const ColumnPtr & src, const ColumnsWithTypeAndName & args, const DataTypePtr & result_type, size_t input_rows_count)
{
    ColumnPtr result_null_map_column;

    /// If result is already nullable.
    ColumnPtr src_not_nullable = src;

    if (src->onlyNull())
        return src;
    else if (const auto * nullable = checkAndGetColumn<ColumnNullable>(*src))
    {
        src_not_nullable = nullable->getNestedColumnPtr();
        result_null_map_column = nullable->getNullMapColumnPtr();
    }

    for (const auto & elem : args)
    {
        if (!elem.type->isNullable())
            continue;

        /// Const Nullable that are NULL.
        if (elem.column->onlyNull())
        {
            assert(result_type->isNullable());
            return result_type->createColumnConstWithDefaultValue(input_rows_count);
        }

        if (isColumnConst(*elem.column))
            continue;

        if (const auto * nullable = checkAndGetColumn<ColumnNullable>(*elem.column))
        {
            const ColumnPtr & null_map_column = nullable->getNullMapColumnPtr();
            if (!result_null_map_column)
            {
                result_null_map_column = null_map_column;
            }
            else
            {
                MutableColumnPtr mutable_result_null_map_column = IColumn::mutate(std::move(result_null_map_column));

                NullMap & result_null_map = assert_cast<ColumnUInt8 &>(*mutable_result_null_map_column).getData();
                const NullMap & src_null_map = assert_cast<const ColumnUInt8 &>(*null_map_column).getData();

                for (size_t i = 0, size = result_null_map.size(); i < size; ++i)
                    result_null_map[i] |= src_null_map[i];

                result_null_map_column = std::move(mutable_result_null_map_column);
            }
        }
    }

    if (!result_null_map_column)
        return makeNullable(src);

    return ColumnNullable::create(src_not_nullable->convertToFullColumnIfConst(), result_null_map_column);
}

NullPresence getNullPresense(const ColumnsWithTypeAndName & args)
{
    NullPresence res;

    for (const auto & elem : args)
    {
        res.has_nullable |= elem.type->isNullable();
        res.has_null_constant |= elem.type->onlyNull();
    }

    return res;
}

bool isDecimalOrNullableDecimal(const DataTypePtr & type)
{
    WhichDataType which(type);
    if (which.isDecimal())
        return true;
    if (!which.isNullable())
        return false;
    return isDecimal(assert_cast<const DataTypeNullable *>(type.get())->getNestedType());
}

}