ClickHouse/dbms/src/Functions/arrayPush.h
2018-09-10 00:15:40 +03:00

115 lines
4.1 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/GatherUtils/GatherUtils.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/getLeastSupertype.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnConst.h>
#include <Interpreters/castColumn.h>
#include <Common/typeid_cast.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
class FunctionArrayPush : public IFunction
{
public:
FunctionArrayPush(const Context & context, bool push_front, const char * name)
: context(context), push_front(push_front), name(name) {}
String getName() const override { return name; }
bool isVariadic() const override { return false; }
size_t getNumberOfArguments() const override { return 2; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (arguments[0]->onlyNull())
return arguments[0];
auto array_type = typeid_cast<const DataTypeArray *>(arguments[0].get());
if (!array_type)
throw Exception("First argument for function " + getName() + " must be an array but it has type "
+ arguments[0]->getName() + ".", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
auto nested_type = array_type->getNestedType();
DataTypes types = {nested_type, arguments[1]};
return std::make_shared<DataTypeArray>(getLeastSupertype(types));
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) override
{
const auto & return_type = block.getByPosition(result).type;
if (return_type->onlyNull())
{
block.getByPosition(result).column = return_type->createColumnConstWithDefaultValue(input_rows_count);
return;
}
auto result_column = return_type->createColumn();
auto array_column = block.getByPosition(arguments[0]).column;
auto appended_column = block.getByPosition(arguments[1]).column;
if (!block.getByPosition(arguments[0]).type->equals(*return_type))
array_column = castColumn(block.getByPosition(arguments[0]), return_type, context);
const DataTypePtr & return_nested_type = typeid_cast<const DataTypeArray &>(*return_type).getNestedType();
if (!block.getByPosition(arguments[1]).type->equals(*return_nested_type))
appended_column = castColumn(block.getByPosition(arguments[1]), return_nested_type, context);
std::unique_ptr<GatherUtils::IArraySource> array_source;
std::unique_ptr<GatherUtils::IValueSource> value_source;
size_t size = array_column->size();
bool is_const = false;
if (auto const_array_column = typeid_cast<const ColumnConst *>(array_column.get()))
{
is_const = true;
array_column = const_array_column->getDataColumnPtr();
}
if (auto argument_column_array = typeid_cast<const ColumnArray *>(array_column.get()))
array_source = GatherUtils::createArraySource(*argument_column_array, is_const, size);
else
throw Exception{"First arguments for function " + getName() + " must be array.", ErrorCodes::LOGICAL_ERROR};
bool is_appended_const = false;
if (auto const_appended_column = typeid_cast<const ColumnConst *>(appended_column.get()))
{
is_appended_const = true;
appended_column = const_appended_column->getDataColumnPtr();
}
value_source = GatherUtils::createValueSource(*appended_column, is_appended_const, size);
auto sink = GatherUtils::createArraySink(typeid_cast<ColumnArray &>(*result_column), size);
GatherUtils::push(*array_source, *value_source, *sink, push_front);
block.getByPosition(result).column = std::move(result_column);
}
bool useDefaultImplementationForConstants() const override { return true; }
bool useDefaultImplementationForNulls() const override { return false; }
private:
const Context & context;
bool push_front;
const char * name;
};
}