ClickHouse/src/DataTypes/DataTypeAggregateFunction.h

90 lines
3.3 KiB
C++

#pragma once
#include <AggregateFunctions/IAggregateFunction.h>
#include <DataTypes/IDataType.h>
namespace DB
{
/** Type - the state of the aggregate function.
* Type parameters is an aggregate function, the types of its arguments, and its parameters (for parametric aggregate functions).
*
* Data type can support versioning for serialization of aggregate function state.
* Version 0 also means no versioning. When a table with versioned data type is attached, its version is parsed from AST. If
* there is no version in AST, then it is either attach with no version in metadata (then version is 0) or it
* is a new data type (then version is default - latest).
*/
class DataTypeAggregateFunction final : public IDataType
{
private:
AggregateFunctionPtr function;
DataTypes argument_types;
Array parameters;
mutable std::optional<size_t> version;
String getNameImpl(bool with_version) const;
size_t getVersion() const;
public:
static constexpr bool is_parametric = true;
DataTypeAggregateFunction(const AggregateFunctionPtr & function_, const DataTypes & argument_types_,
const Array & parameters_, std::optional<size_t> version_ = std::nullopt)
: function(function_)
, argument_types(argument_types_)
, parameters(parameters_)
, version(version_)
{
}
String getFunctionName() const { return function->getName(); }
AggregateFunctionPtr getFunction() const { return function; }
String doGetName() const override;
String getNameWithoutVersion() const;
const char * getFamilyName() const override { return "AggregateFunction"; }
TypeIndex getTypeId() const override { return TypeIndex::AggregateFunction; }
Array getParameters() const { return parameters; }
bool canBeInsideNullable() const override { return false; }
DataTypePtr getReturnType() const { return function->getReturnType(); }
DataTypePtr getReturnTypeToPredict() const { return function->getReturnTypeToPredict(); }
DataTypes getArgumentsDataTypes() const { return argument_types; }
MutableColumnPtr createColumn() const override;
Field getDefault() const override;
bool equals(const IDataType & rhs) const override;
bool isParametric() const override { return true; }
bool haveSubtypes() const override { return false; }
bool shouldAlignRightInPrettyFormats() const override { return false; }
SerializationPtr doGetDefaultSerialization() const override;
bool supportsSparseSerialization() const override { return false; }
bool isVersioned() const { return function->isVersioned(); }
size_t getVersionFromRevision(size_t revision) const { return function->getVersionFromRevision(revision); }
/// Version is not empty only if it was parsed from AST or implicitly cast to 0 or version according
/// to server revision.
/// It is ok to have an empty version value here - then for serialization a default (latest)
/// version is used. This method is used to force some zero version to be used instead of
/// default, or to set version for serialization in distributed queries.
void setVersion(size_t version_, bool if_empty) const
{
if (version && if_empty)
return;
version = version_;
}
};
}