ClickHouse/dbms/src/Functions/FunctionFactory.cpp

99 lines
2.7 KiB
C++

#include <Functions/FunctionFactory.h>
#include <Interpreters/Context.h>
#include <Common/Exception.h>
#include <Poco/String.h>
#include <IO/WriteHelpers.h>
namespace DB
{
namespace ErrorCodes
{
extern const int UNKNOWN_FUNCTION;
extern const int LOGICAL_ERROR;
}
void FunctionFactory::registerFunction(const
std::string & name,
Creator creator,
CaseSensitiveness case_sensitiveness)
{
if (!functions.emplace(name, creator).second)
throw Exception("FunctionFactory: the function name '" + name + "' is not unique",
ErrorCodes::LOGICAL_ERROR);
String function_name_lowercase = Poco::toLower(name);
if (isAlias(name) || isAlias(function_name_lowercase))
throw Exception("FunctionFactory: the function name '" + name + "' is already registered as alias",
ErrorCodes::LOGICAL_ERROR);
if (case_sensitiveness == CaseInsensitive
&& !case_insensitive_functions.emplace(function_name_lowercase, creator).second)
throw Exception("FunctionFactory: the case insensitive function name '" + name + "' is not unique",
ErrorCodes::LOGICAL_ERROR);
}
FunctionOverloadResolverImplPtr FunctionFactory::getImpl(
const std::string & name,
const Context & context) const
{
auto res = tryGetImpl(name, context);
if (!res)
{
auto hints = this->getHints(name);
if (!hints.empty())
throw Exception("Unknown function " + name + ". Maybe you meant: " + toString(hints),
ErrorCodes::UNKNOWN_FUNCTION);
else
throw Exception("Unknown function " + name, ErrorCodes::UNKNOWN_FUNCTION);
}
return res;
}
FunctionOverloadResolverPtr FunctionFactory::get(
const std::string & name,
const Context & context) const
{
return std::make_shared<FunctionOverloadResolverAdaptor>(getImpl(name, context));
}
FunctionOverloadResolverImplPtr FunctionFactory::tryGetImpl(
const std::string & name_param,
const Context & context) const
{
String name = getAliasToOrName(name_param);
auto it = functions.find(name);
if (functions.end() != it)
return it->second(context);
it = case_insensitive_functions.find(Poco::toLower(name));
if (case_insensitive_functions.end() != it)
return it->second(context);
return {};
}
FunctionOverloadResolverPtr FunctionFactory::tryGet(
const std::string & name,
const Context & context) const
{
auto impl = tryGetImpl(name, context);
return impl ? std::make_shared<FunctionOverloadResolverAdaptor>(std::move(impl))
: nullptr;
}
FunctionFactory & FunctionFactory::instance()
{
static FunctionFactory ret;
return ret;
}
}