1 | #include <Functions/IFunctionImpl.h> |
---|---|
2 | #include <Functions/FunctionHelpers.h> |
3 | #include <Functions/FunctionFactory.h> |
4 | #include <DataTypes/DataTypeNullable.h> |
5 | #include <Core/ColumnNumbers.h> |
6 | #include <Columns/ColumnNullable.h> |
7 | |
8 | |
9 | namespace DB |
10 | { |
11 | |
12 | /// Implements the function assumeNotNull which takes 1 argument and works as follows: |
13 | /// - if the argument is a nullable column, return its embedded column; |
14 | /// - otherwise return the original argument. |
15 | /// NOTE: assumeNotNull may not be called with the NULL value. |
16 | class FunctionAssumeNotNull : public IFunction |
17 | { |
18 | public: |
19 | static constexpr auto name = "assumeNotNull"; |
20 | |
21 | static FunctionPtr create(const Context &) |
22 | { |
23 | return std::make_shared<FunctionAssumeNotNull>(); |
24 | } |
25 | |
26 | std::string getName() const override |
27 | { |
28 | return name; |
29 | } |
30 | |
31 | size_t getNumberOfArguments() const override { return 1; } |
32 | bool useDefaultImplementationForNulls() const override { return false; } |
33 | bool useDefaultImplementationForConstants() const override { return true; } |
34 | ColumnNumbers getArgumentsThatDontImplyNullableReturnType(size_t /*number_of_arguments*/) const override { return {0}; } |
35 | |
36 | DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override |
37 | { |
38 | return removeNullable(arguments[0]); |
39 | } |
40 | |
41 | void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t) override |
42 | { |
43 | const ColumnPtr & col = block.getByPosition(arguments[0]).column; |
44 | ColumnPtr & res_col = block.getByPosition(result).column; |
45 | |
46 | if (auto * nullable_col = checkAndGetColumn<ColumnNullable>(*col)) |
47 | res_col = nullable_col->getNestedColumnPtr(); |
48 | else |
49 | res_col = col; |
50 | } |
51 | }; |
52 | |
53 | |
54 | void registerFunctionAssumeNotNull(FunctionFactory & factory) |
55 | { |
56 | factory.registerFunction<FunctionAssumeNotNull>(); |
57 | } |
58 | |
59 | } |
60 |