ClickHouse/src/AggregateFunctions/AggregateFunctionSimpleState.h
2021-02-01 20:12:12 +03:00

86 lines
3.4 KiB
C++

#pragma once
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <AggregateFunctions/IAggregateFunction.h>
#include <DataTypes/DataTypeCustomSimpleAggregateFunction.h>
#include <DataTypes/DataTypeFactory.h>
namespace DB
{
/** Not an aggregate function, but an adapter of aggregate functions.
* Aggregate functions with the `SimpleState` suffix is almost identical to the corresponding ones,
* except the return type becomes DataTypeCustomSimpleAggregateFunction.
*/
class AggregateFunctionSimpleState final : public IAggregateFunctionHelper<AggregateFunctionSimpleState>
{
private:
AggregateFunctionPtr nested_func;
DataTypes arguments;
Array params;
public:
AggregateFunctionSimpleState(AggregateFunctionPtr nested_, const DataTypes & arguments_, const Array & params_)
: IAggregateFunctionHelper<AggregateFunctionSimpleState>(arguments_, params_)
, nested_func(nested_)
, arguments(arguments_)
, params(params_)
{
}
String getName() const override { return nested_func->getName() + "SimpleState"; }
DataTypePtr getReturnType() const override
{
DataTypeCustomSimpleAggregateFunction::checkSupportedFunctions(nested_func);
// Need to make a clone because it'll be customized.
auto storage_type = DataTypeFactory::instance().get(nested_func->getReturnType()->getName());
// Need to make a new function with promoted argument types because SimpleAggregates requires arg_type = return_type.
AggregateFunctionProperties properties;
auto function
= AggregateFunctionFactory::instance().get(nested_func->getName(), {storage_type}, nested_func->getParameters(), properties);
DataTypeCustomNamePtr custom_name
= std::make_unique<DataTypeCustomSimpleAggregateFunction>(function, DataTypes{nested_func->getReturnType()}, params);
storage_type->setCustomization(std::make_unique<DataTypeCustomDesc>(std::move(custom_name), nullptr));
return storage_type;
}
void create(AggregateDataPtr __restrict place) const override { nested_func->create(place); }
void destroy(AggregateDataPtr __restrict place) const noexcept override { nested_func->destroy(place); }
bool hasTrivialDestructor() const override { return nested_func->hasTrivialDestructor(); }
size_t sizeOfData() const override { return nested_func->sizeOfData(); }
size_t alignOfData() const override { return nested_func->alignOfData(); }
void add(AggregateDataPtr __restrict place, const IColumn ** columns, size_t row_num, Arena * arena) const override
{
nested_func->add(place, columns, row_num, arena);
}
void merge(AggregateDataPtr __restrict place, ConstAggregateDataPtr rhs, Arena * arena) const override { nested_func->merge(place, rhs, arena); }
void serialize(ConstAggregateDataPtr __restrict place, WriteBuffer & buf) const override { nested_func->serialize(place, buf); }
void deserialize(AggregateDataPtr __restrict place, ReadBuffer & buf, Arena * arena) const override
{
nested_func->deserialize(place, buf, arena);
}
void insertResultInto(AggregateDataPtr __restrict place, IColumn & to, Arena * arena) const override
{
nested_func->insertResultInto(place, to, arena);
}
bool allocatesMemoryInArena() const override { return nested_func->allocatesMemoryInArena(); }
AggregateFunctionPtr getNestedFunction() const override { return nested_func; }
};
}