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4088c0a7f3
Automated register all functions with below naming convention by iterating through the symbols: void DB::registerXXX(DB::FunctionFactory &)
72 lines
2.5 KiB
C++
72 lines
2.5 KiB
C++
#include <Functions/IFunction.h>
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#include <Functions/FunctionFactory.h>
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#include <Functions/FunctionHelpers.h>
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#include <DataTypes/FieldToDataType.h>
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#include <Interpreters/convertFieldToType.h>
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#include <Interpreters/Context.h>
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#include <Core/Field.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int ILLEGAL_TYPE_OF_ARGUMENT;
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extern const int ILLEGAL_COLUMN;
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}
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namespace
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{
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/// Get the value of a setting.
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class FunctionGetSetting : public IFunction, WithContext
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{
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public:
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static constexpr auto name = "getSetting";
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static FunctionPtr create(ContextPtr context_) { return std::make_shared<FunctionGetSetting>(context_); }
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explicit FunctionGetSetting(ContextPtr context_) : WithContext(context_) {}
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String getName() const override { return name; }
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bool isDeterministic() const override { return false; }
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bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
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size_t getNumberOfArguments() const override { return 1; }
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ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {0}; }
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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auto value = getValue(arguments);
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return applyVisitor(FieldToDataType{}, value);
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}
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
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{
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auto value = getValue(arguments);
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return result_type->createColumnConst(input_rows_count, convertFieldToType(value, *result_type));
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}
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private:
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Field getValue(const ColumnsWithTypeAndName & arguments) const
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{
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if (!isString(arguments[0].type))
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throw Exception{"The argument of function " + String{name} + " should be a constant string with the name of a setting",
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ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
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const auto * column = arguments[0].column.get();
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if (!column || !checkAndGetColumnConstStringOrFixedString(column))
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throw Exception{"The argument of function " + String{name} + " should be a constant string with the name of a setting",
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ErrorCodes::ILLEGAL_COLUMN};
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std::string_view setting_name{column->getDataAt(0).toView()};
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return getContext()->getSettingsRef().get(setting_name);
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}
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};
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}
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REGISTER_FUNCTION(GetSetting)
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{
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factory.registerFunction<FunctionGetSetting>();
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}
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}
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