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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
1.9 KiB
C++
72 lines
1.9 KiB
C++
#include <Functions/IFunction.h>
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#include <Functions/FunctionFactory.h>
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#include <Core/Field.h>
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#include <Columns/ColumnConst.h>
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#include <DataTypes/DataTypeFactory.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_COLUMN;
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}
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namespace
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{
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/// Returns global default value for type name (example: 0 for numeric types, '' for String).
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class FunctionDefaultValueOfTypeName : public IFunction
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{
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public:
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static constexpr auto name = "defaultValueOfTypeName";
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static FunctionPtr create(ContextPtr)
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{
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return std::make_shared<FunctionDefaultValueOfTypeName>();
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}
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String getName() const override
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{
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return name;
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}
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bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override
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{
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return false;
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}
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bool useDefaultImplementationForNulls() const override { return false; }
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bool useDefaultImplementationForLowCardinalityColumns() const override { return false; }
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size_t getNumberOfArguments() const override
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{
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return 1;
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}
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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const ColumnConst * col_type_const = typeid_cast<const ColumnConst *>(arguments.front().column.get());
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if (!col_type_const || !isString(arguments.front().type))
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throw Exception("The argument of function " + getName() + " must be a constant string describing type.",
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ErrorCodes::ILLEGAL_COLUMN);
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return DataTypeFactory::instance().get(col_type_const->getValue<String>());
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}
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ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr & result_type, size_t input_rows_count) const override
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{
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const IDataType & type = *result_type;
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return type.createColumnConst(input_rows_count, type.getDefault());
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}
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};
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}
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REGISTER_FUNCTION(DefaultValueOfTypeName)
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{
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factory.registerFunction<FunctionDefaultValueOfTypeName>();
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}
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}
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