ClickHouse/dbms/src/Functions/yesterday.cpp

#include <common/DateLUT.h>

#include <DataTypes/DataTypeDate.h>

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>


namespace DB
{

class PreparedFunctionYesterday : public PreparedFunctionImpl
{
public:
    explicit PreparedFunctionYesterday(time_t time_) : day_value(time_) {}

    String getName() const override { return "yesterday"; }

protected:
    void executeImpl(Block & block, const ColumnNumbers &, size_t result, size_t input_rows_count) override
    {
        block.getByPosition(result).column = DataTypeDate().createColumnConst(input_rows_count, day_value);
    }

private:
    DayNum day_value;
};

class FunctionBaseYesterday : public IFunctionBase
{
public:
    explicit FunctionBaseYesterday(DayNum day_value_) : day_value(day_value_), return_type(std::make_shared<DataTypeDate>()) {}

    String getName() const override { return "yesterday"; }

    const DataTypes & getArgumentTypes() const override
    {
        static const DataTypes argument_types;
        return argument_types;
    }

    const DataTypePtr & getReturnType() const override
    {
        return return_type;
    }

    PreparedFunctionPtr prepare(const Block &, const ColumnNumbers &, size_t) const override
    {
        return std::make_shared<PreparedFunctionYesterday>(day_value);
    }

    bool isDeterministic() const override { return false; }

private:
    DayNum day_value;
    DataTypePtr return_type;
};

class FunctionBuilderYesterday : public FunctionBuilderImpl
{
public:
    static constexpr auto name = "yesterday";

    String getName() const override { return name; }
    size_t getNumberOfArguments() const override { return 0; }

    static FunctionBuilderPtr create(const Context &) { return std::make_shared<FunctionBuilderYesterday>(); }

protected:
    DataTypePtr getReturnTypeImpl(const DataTypes &) const override { return std::make_shared<DataTypeDate>(); }

    FunctionBasePtr buildImpl(const ColumnsWithTypeAndName &, const DataTypePtr &) const override
    {
        auto day_num = DateLUT::instance().toDayNum(time(nullptr)) - 1;
        return std::make_shared<FunctionBaseYesterday>(static_cast<DayNum>(day_num));
    }
};

void registerFunctionYesterday(FunctionFactory & factory)
{
    factory.registerFunction<FunctionBuilderYesterday>();
}

}