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Refactor now64

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This commit is contained in:
Nikolai Kochetov 2021-01-20 16:18:41 +03:00
parent 8d58ce532a
commit 6cf4ed5c42
1 changed files with 65 additions and 16 deletions
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81
src/Functions/now64.cpp
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@ -15,6 +15,7 @@ namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int CANNOT_CLOCK_GETTIME;
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
namespace
@ -44,29 +45,77 @@ Field nowSubsecond(UInt32 scale)
scale);
}
class FunctionNow64 : public IFunction
/// Get the current time. (It is a constant, it is evaluated once for the entire query.)
class ExecutableFunctionNow64 : public IExecutableFunctionImpl
{
public:
explicit ExecutableFunctionNow64(Field time_) : time_value(time_) {}
String getName() const override { return "now64"; }
ColumnPtr execute(const ColumnsWithTypeAndName &, const DataTypePtr & result_type, size_t input_rows_count) const override
{
return result_type->createColumnConst(input_rows_count, time_value);
}
private:
Field time_value;
};
class FunctionBaseNow64 : public IFunctionBaseImpl
{
public:
explicit FunctionBaseNow64(Field time_, DataTypePtr return_type_) : time_value(time_), return_type(return_type_) {}
String getName() const override { return "now64"; }
const DataTypes & getArgumentTypes() const override
{
static const DataTypes argument_types;
return argument_types;
}
const DataTypePtr & getResultType() const override
{
return return_type;
}
ExecutableFunctionImplPtr prepare(const ColumnsWithTypeAndName &) const override
{
return std::make_unique<ExecutableFunctionNow64>(time_value);
}
bool isDeterministic() const override { return false; }
bool isDeterministicInScopeOfQuery() const override { return true; }
private:
Field time_value;
DataTypePtr return_type;
};
class Now64OverloadResolver : public IFunctionOverloadResolverImpl
{
public:
static constexpr auto name = "now64";
static FunctionPtr create(const Context &) { return std::make_shared<FunctionNow64>(); }
String getName() const override
{
return name;
}
String getName() const override { return name; }
bool isVariadic() const override { return true; }
size_t getNumberOfArguments() const override { return 0; }
ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return ColumnNumbers{0}; }
bool isDeterministic() const override { return false; }
// Return type depends on argument value.
DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
bool isVariadic() const override { return true; }
size_t getNumberOfArguments() const override { return 0; }
static FunctionOverloadResolverImplPtr create(const Context &) { return std::make_unique<Now64OverloadResolver>(); }
DataTypePtr getReturnType(const ColumnsWithTypeAndName & arguments) const override
{
UInt32 scale = DataTypeDateTime64::default_scale;
// Type check is similar to the validateArgumentType, trying to keep error codes and messages as close to the said function as possible.
if (!arguments.empty())
if (arguments.size() > 1)
{
throw Exception("Arguments size of function " + getName() + " should be 0 or 1", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
}
if (arguments.size() == 1)
{
const auto & argument = arguments[0];
if (!isInteger(argument.type) || !argument.column || !isColumnConst(*argument.column))
@ -82,10 +131,10 @@ public:
return std::make_shared<DataTypeDateTime64>(scale);
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName &, const DataTypePtr & result_type, size_t input_rows_count) const override
FunctionBaseImplPtr build(const ColumnsWithTypeAndName &, const DataTypePtr & result_type) const override
{
const UInt32 scale = assert_cast<const DataTypeDateTime64 *>(result_type.get())->getScale();
return result_type->createColumnConst(input_rows_count, nowSubsecond(scale));
return std::make_unique<FunctionBaseNow64>(nowSubsecond(scale), result_type);
}
};
@ -93,7 +142,7 @@ public:
void registerFunctionNow64(FunctionFactory & factory)
{
factory.registerFunction<FunctionNow64>(FunctionFactory::CaseInsensitive);
factory.registerFunction<Now64OverloadResolver>(FunctionFactory::CaseInsensitive);
}
}