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#pragma once
#include <AggregateFunctions/IAggregateFunction.h>
#include <Common/IFactoryWithAliases.h>
#include <Parsers/ASTFunction.h>
#include <functional>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>
#include <optional>
namespace DB
{
struct Settings;
class Context;
class IDataType;
using DataTypePtr = std::shared_ptr<const IDataType>;
using DataTypes = std::vector<DataTypePtr>;
/**
* The invoker has arguments: name of aggregate function, types of arguments, values of parameters.
* Parameters are for "parametric" aggregate functions.
* For example, in quantileWeighted(0.9)(x, weight), 0.9 is "parameter" and x, weight are "arguments".
*/
using AggregateFunctionCreator = std::function<AggregateFunctionPtr(const String &, const DataTypes &, const Array &, const Settings *)>;
struct AggregateFunctionWithProperties
{
AggregateFunctionCreator creator;
AggregateFunctionProperties properties;
AggregateFunctionWithProperties() = default;
AggregateFunctionWithProperties(const AggregateFunctionWithProperties &) = default;
AggregateFunctionWithProperties & operator = (const AggregateFunctionWithProperties &) = default;
template <typename Creator>
requires (!std::is_same_v<Creator, AggregateFunctionWithProperties>)
AggregateFunctionWithProperties(Creator creator_, AggregateFunctionProperties properties_ = {}) /// NOLINT
: creator(std::forward<Creator>(creator_)), properties(std::move(properties_))
{
}
};
/** Creates an aggregate function by name.
*/
class AggregateFunctionFactory final : private boost::noncopyable, public IFactoryWithAliases<AggregateFunctionWithProperties>
{
public:
static AggregateFunctionFactory & instance();
/// Register a function by its name.
/// No locking, you must register all functions before usage of get.
void registerFunction(
const String & name,
Value creator,
CaseSensitiveness case_sensitiveness = CaseSensitive);
/// Throws an exception if not found.
AggregateFunctionPtr
get(const String & name,
const DataTypes & argument_types,
const Array & parameters,
AggregateFunctionProperties & out_properties) const;
/// Returns nullptr if not found.
AggregateFunctionPtr tryGet(
const String & name,
const DataTypes & argument_types,
const Array & parameters,
AggregateFunctionProperties & out_properties) const;
/// Get properties if the aggregate function exists.
std::optional<AggregateFunctionProperties> tryGetProperties(String name) const;
bool isAggregateFunctionName(String name) const;
private:
AggregateFunctionPtr getImpl(
const String & name,
const DataTypes & argument_types,
const Array & parameters,
AggregateFunctionProperties & out_properties,
bool has_null_arguments) const;
using AggregateFunctions = std::unordered_map<String, Value>;
AggregateFunctions aggregate_functions;
/// Case insensitive aggregate functions will be additionally added here with lowercased name.
AggregateFunctions case_insensitive_aggregate_functions;
const AggregateFunctions & getMap() const override { return aggregate_functions; }
const AggregateFunctions & getCaseInsensitiveMap() const override { return case_insensitive_aggregate_functions; }
String getFactoryName() const override { return "AggregateFunctionFactory"; }
};
struct AggregateUtils
{
static bool isAggregateFunction(const ASTFunction & node)
{
return AggregateFunctionFactory::instance().isAggregateFunctionName(node.name);
}
};
const String & getAggregateFunctionCanonicalNameIfAny(const String & name);
}
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