[#MDEV-17182] Move fractional second truncation outside of Field_xxx::store_TIME_with

This task is self-sufficient change ~~MDEV-16991~~.

To make the main ~~MDEV-16991~~ patch simpler, we'll move fractional second truncation from these methods:

int Field_timestamp::store_TIME_with_warning()

int Field_temporal_with_date::store_TIME_with_warning()

int Field_time::store_TIME_with_warning()

to the caller level. store_TIME_with_warning() will get an already properly truncated value.

We'll also add truncating constructors for Time and Datetime.

For example, for Datetime, the new constructors will looks approximately like this:

  Datetime(MYSQL_TIME_STATUS *status,

           const char *str, size_t len, CHARSET_INFO *cs,

           sql_mode_t fuzzydate, uint dec)

   :Temporal_with_date(Datetime(status, str, len, cs, fuzzydate))

    trunc(dec);

  Datetime(int *warn, double nr, sql_mode_t fuzzydate, uint dec)

   :Temporal_with_date(Datetime(warn, nr, fuzzydate))

    trunc(dec);

  Datetime(int *warn, const my_decimal *d, sql_mode_t fuzzydate, uint dec)

   :Temporal_with_date(Datetime(warn, d, fuzzydate))

    trunc(dec);

  Datetime(THD *thd, int *warn, const MYSQL_TIME *from,

           sql_mode_t fuzzydate, uint dec)

   :Temporal_with_date(Datetime(thd, warn, from, fuzzydate))

    trunc(dec);

The callers will be changed to truncate the value before passing it to store_TIME_with_warn(). For example, in case of string-to-TIME conversion, the change will look like this:

 int Field_time::store(const char *from,size_t len,CHARSET_INFO *cs)

   ErrConvString str(from, len, cs);

   MYSQL_TIME_STATUS st;

-  Time tm(&st, from, len, cs, sql_mode_for_dates(get_thd()));

+  Time tm(&st, from, len, cs, sql_mode_for_dates(get_thd()), decimals());

   return store_TIME_with_warning(&tm, &str, st.warnings);

Later, in the main patch for ~~MDEV-16991~~, all truncating Time and Datetime constructors will be fixed to choose between truncation and rounding, according to the current session options.

[MDEV-17182] Move fractional second truncation outside of Field_xxx::store_TIME_with_warn() Created: 2018-09-12 Updated: 2018-09-16 Resolved: 2018-09-12
Status:	Closed
Project:	MariaDB Server
Component/s:	Data types, Temporal Types
Fix Version/s:	10.4.0

[MDEV-17182] Move fractional second truncation outside of Field_xxx::store_TIME_with_warn() Created: 2018-09-12 Updated: 2018-09-16 Resolved: 2018-09-12