mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-22 07:31:57 +00:00
283 lines
10 KiB
C++
283 lines
10 KiB
C++
#pragma once
|
||
|
||
#include <string.h>
|
||
#include <stdio.h>
|
||
#include <time.h>
|
||
#include <math.h>
|
||
|
||
#include <string>
|
||
#include <limits>
|
||
|
||
#include <common/preciseExp10.h>
|
||
#include <common/types.h>
|
||
#include <common/DateLUT.h>
|
||
|
||
#include <mysqlxx/Types.h>
|
||
#include <common/LocalDateTime.h>
|
||
|
||
|
||
namespace mysqlxx
|
||
{
|
||
|
||
|
||
class ResultBase;
|
||
|
||
|
||
/** Represents a single value read from MySQL.
|
||
* It doesn't owns the value. It's just a wrapper of a pair (const char *, size_t).
|
||
* If the UseQueryResult or Connection is destroyed,
|
||
* or you have read the next Row while using UseQueryResult, then the object is invalidated.
|
||
* Allows to transform (parse) the value to various data types:
|
||
* - with getUInt(), getString(), ... (recommended);
|
||
* - with template function get<Type>() that is specialized for multiple data types;
|
||
* - the template function get<Type> also works for all types that can be constructed from Value
|
||
* (it is an extension point);
|
||
* - with operator Type() - this is done for compatibility and not recommended because ambiguities possible.
|
||
*
|
||
* On parsing error, exception is thrown.
|
||
* When trying to extract a value that is nullptr, exception is thrown
|
||
* - use isNull() method to check.
|
||
*
|
||
* As time_t is just an alias for integer data type
|
||
* to allow to write row[0].get<time_t>(), and expect that the values like '2011-01-01 00:00:00'
|
||
* will be successfully parsed according to the current time zone,
|
||
* the getUInt method and the corresponding get<>() methods
|
||
* are capable of parsing Date and DateTime.
|
||
*/
|
||
class Value
|
||
{
|
||
public:
|
||
/** Параметр res_ используется только для генерации подробной информации в исключениях.
|
||
* Можно передать NULL - тогда подробной информации в исключениях не будет.
|
||
*/
|
||
Value(const char * data_, size_t length_, const ResultBase * res_) : m_data(data_), m_length(length_), res(res_)
|
||
{
|
||
}
|
||
|
||
/// Получить значение bool.
|
||
bool getBool() const
|
||
{
|
||
if (unlikely(isNull()))
|
||
throwException("Value is NULL");
|
||
|
||
return m_length > 0 && m_data[0] != '0';
|
||
}
|
||
|
||
/// Получить беззнаковое целое.
|
||
UInt64 getUInt() const
|
||
{
|
||
if (unlikely(isNull()))
|
||
throwException("Value is NULL");
|
||
|
||
return readUIntText(m_data, m_length);
|
||
}
|
||
|
||
/// Получить целое со знаком или дату или дату-время (в unix timestamp согласно текущей тайм-зоне).
|
||
Int64 getInt() const
|
||
{
|
||
return getIntOrDateTime();
|
||
}
|
||
|
||
/// Получить число с плавающей запятой.
|
||
double getDouble() const
|
||
{
|
||
if (unlikely(isNull()))
|
||
throwException("Value is NULL");
|
||
|
||
return readFloatText(m_data, m_length);
|
||
}
|
||
|
||
/// Получить дату-время (из значения вида '2011-01-01 00:00:00').
|
||
LocalDateTime getDateTime() const
|
||
{
|
||
return LocalDateTime(data(), size());
|
||
}
|
||
|
||
/// Получить дату (из значения вида '2011-01-01' или '2011-01-01 00:00:00').
|
||
LocalDate getDate() const
|
||
{
|
||
return LocalDate(data(), size());
|
||
}
|
||
|
||
/// Получить строку.
|
||
std::string getString() const
|
||
{
|
||
if (unlikely(isNull()))
|
||
throwException("Value is NULL");
|
||
|
||
return std::string(m_data, m_length);
|
||
}
|
||
|
||
/// Является ли NULL.
|
||
bool isNull() const
|
||
{
|
||
return m_data == nullptr;
|
||
}
|
||
|
||
/// Для совместимости (используйте вместо этого метод isNull())
|
||
bool is_null() const { return isNull(); }
|
||
|
||
/** Получить любой поддерживаемый тип (для шаблонного кода).
|
||
* Поддерживаются основные типы, а также любые типы с конструктором от Value (для удобства расширения).
|
||
*/
|
||
template <typename T> T get() const;
|
||
|
||
/// Для совместимости. Не рекомендуется к использованию, так как неудобен (часто возникают неоднозначности).
|
||
template <typename T> operator T() const { return get<T>(); }
|
||
|
||
const char * data() const { return m_data; }
|
||
size_t length() const { return m_length; }
|
||
size_t size() const { return m_length; }
|
||
bool empty() const { return 0 == m_length; }
|
||
|
||
private:
|
||
const char * m_data;
|
||
size_t m_length;
|
||
const ResultBase * res;
|
||
|
||
|
||
bool checkDateTime() const
|
||
{
|
||
return (m_length == 10 || m_length == 19) && m_data[4] == '-' && m_data[7] == '-';
|
||
}
|
||
|
||
|
||
time_t getDateTimeImpl() const
|
||
{
|
||
const auto & date_lut = DateLUT::instance();
|
||
|
||
if (m_length == 10)
|
||
{
|
||
return date_lut.makeDate(
|
||
(m_data[0] - '0') * 1000 + (m_data[1] - '0') * 100 + (m_data[2] - '0') * 10 + (m_data[3] - '0'),
|
||
(m_data[5] - '0') * 10 + (m_data[6] - '0'),
|
||
(m_data[8] - '0') * 10 + (m_data[9] - '0'));
|
||
}
|
||
else if (m_length == 19)
|
||
{
|
||
return date_lut.makeDateTime(
|
||
(m_data[0] - '0') * 1000 + (m_data[1] - '0') * 100 + (m_data[2] - '0') * 10 + (m_data[3] - '0'),
|
||
(m_data[5] - '0') * 10 + (m_data[6] - '0'),
|
||
(m_data[8] - '0') * 10 + (m_data[9] - '0'),
|
||
(m_data[11] - '0') * 10 + (m_data[12] - '0'),
|
||
(m_data[14] - '0') * 10 + (m_data[15] - '0'),
|
||
(m_data[17] - '0') * 10 + (m_data[18] - '0'));
|
||
}
|
||
else
|
||
throwException("Cannot parse DateTime");
|
||
|
||
return 0; /// avoid warning.
|
||
}
|
||
|
||
|
||
time_t getDateImpl() const
|
||
{
|
||
const auto & date_lut = DateLUT::instance();
|
||
|
||
if (m_length == 10 || m_length == 19)
|
||
{
|
||
return date_lut.makeDate(
|
||
(m_data[0] - '0') * 1000 + (m_data[1] - '0') * 100 + (m_data[2] - '0') * 10 + (m_data[3] - '0'),
|
||
(m_data[5] - '0') * 10 + (m_data[6] - '0'),
|
||
(m_data[8] - '0') * 10 + (m_data[9] - '0'));
|
||
}
|
||
else
|
||
throwException("Cannot parse Date");
|
||
|
||
return 0; /// avoid warning.
|
||
}
|
||
|
||
|
||
Int64 getIntImpl() const
|
||
{
|
||
return readIntText(m_data, m_length);
|
||
}
|
||
|
||
|
||
Int64 getIntOrDateTime() const
|
||
{
|
||
if (unlikely(isNull()))
|
||
throwException("Value is NULL");
|
||
|
||
if (checkDateTime())
|
||
return getDateTimeImpl();
|
||
else
|
||
return getIntImpl();
|
||
}
|
||
|
||
|
||
Int64 getIntOrDate() const
|
||
{
|
||
if (unlikely(isNull()))
|
||
throwException("Value is NULL");
|
||
|
||
if (checkDateTime())
|
||
return getDateImpl();
|
||
else
|
||
{
|
||
const auto & date_lut = DateLUT::instance();
|
||
return date_lut.toDate(getIntImpl());
|
||
}
|
||
}
|
||
|
||
|
||
/// Прочитать беззнаковое целое в простом формате из не-0-terminated строки.
|
||
UInt64 readUIntText(const char * buf, size_t length) const;
|
||
|
||
/// Прочитать знаковое целое в простом формате из не-0-terminated строки.
|
||
Int64 readIntText(const char * buf, size_t length) const;
|
||
|
||
/// Прочитать число с плавающей запятой в простом формате, с грубым округлением, из не-0-terminated строки.
|
||
double readFloatText(const char * buf, size_t length) const;
|
||
|
||
/// Выкинуть исключение с подробной информацией
|
||
[[noreturn]] void throwException(const char * text) const;
|
||
};
|
||
|
||
|
||
template <> inline bool Value::get<bool >() const { return getBool(); }
|
||
template <> inline char Value::get<char >() const { return getInt(); }
|
||
template <> inline signed char Value::get<signed char >() const { return getInt(); }
|
||
template <> inline unsigned char Value::get<unsigned char >() const { return getUInt(); }
|
||
template <> inline char8_t Value::get<char8_t >() const { return getUInt(); }
|
||
template <> inline short Value::get<short >() const { return getInt(); }
|
||
template <> inline unsigned short Value::get<unsigned short >() const { return getUInt(); }
|
||
template <> inline int Value::get<int >() const { return getInt(); }
|
||
template <> inline unsigned int Value::get<unsigned int >() const { return getUInt(); }
|
||
template <> inline long Value::get<long >() const { return getInt(); }
|
||
template <> inline unsigned long Value::get<unsigned long >() const { return getUInt(); }
|
||
template <> inline long long Value::get<long long >() const { return getInt(); }
|
||
template <> inline unsigned long long Value::get<unsigned long long >() const { return getUInt(); }
|
||
template <> inline float Value::get<float >() const { return getDouble(); }
|
||
template <> inline double Value::get<double >() const { return getDouble(); }
|
||
template <> inline std::string Value::get<std::string >() const { return getString(); }
|
||
template <> inline LocalDate Value::get<LocalDate >() const { return getDate(); }
|
||
template <> inline LocalDateTime Value::get<LocalDateTime >() const { return getDateTime(); }
|
||
|
||
|
||
namespace details
|
||
{
|
||
// To avoid stack overflow when converting to type with no appropriate c-tor,
|
||
// resulting in endless recursive calls from `Value::get<T>()` to `Value::operator T()` to `Value::get<T>()` to ...
|
||
template <typename T, typename std::enable_if_t<std::is_constructible_v<T, Value>>>
|
||
inline T contructFromValue(const Value & val)
|
||
{
|
||
return T(val);
|
||
}
|
||
}
|
||
|
||
template <typename T>
|
||
inline T Value::get() const
|
||
{
|
||
return details::contructFromValue<T>(*this);
|
||
}
|
||
|
||
|
||
inline std::ostream & operator<< (std::ostream & ostr, const Value & x)
|
||
{
|
||
return ostr.write(x.data(), x.size());
|
||
}
|
||
|
||
|
||
}
|