ClickHouse/src/Functions/demange.cpp

106 lines
2.9 KiB
C++

#include <base/demangle.h>
#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeString.h>
#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <IO/WriteHelpers.h>
#include <Access/Common/AccessFlags.h>
#include <Interpreters/Context.h>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
namespace
{
class FunctionDemangle : public IFunction
{
public:
static constexpr auto name = "demangle";
static FunctionPtr create(ContextPtr context)
{
context->checkAccess(AccessType::demangle);
return std::make_shared<FunctionDemangle>();
}
String getName() const override
{
return name;
}
size_t getNumberOfArguments() const override
{
return 1;
}
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override
{
return true;
}
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
{
if (arguments.size() != 1)
throw Exception("Function " + getName() + " needs exactly one argument; passed "
+ toString(arguments.size()) + ".", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
const auto & type = arguments[0].type;
if (!WhichDataType(type.get()).isString())
throw Exception("The only argument for function " + getName() + " must be String. Found "
+ type->getName() + " instead.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
return std::make_shared<DataTypeString>();
}
bool useDefaultImplementationForConstants() const override
{
return true;
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
{
const ColumnPtr & column = arguments[0].column;
const ColumnString * column_concrete = checkAndGetColumn<ColumnString>(column.get());
if (!column_concrete)
throw Exception("Illegal column " + column->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_COLUMN);
auto result_column = ColumnString::create();
for (size_t i = 0; i < input_rows_count; ++i)
{
StringRef source = column_concrete->getDataAtWithTerminatingZero(i);
auto demangled = tryDemangle(source.data);
if (demangled)
{
result_column->insertDataWithTerminatingZero(demangled.get(), strlen(demangled.get()) + 1);
}
else
{
result_column->insertDataWithTerminatingZero(source.data, source.size);
}
}
return result_column;
}
};
}
void registerFunctionDemangle(FunctionFactory & factory)
{
factory.registerFunction<FunctionDemangle>();
}
}