In Windows libtime populate `time::Tm` from `SYSTEMTIME`, which
unfortunately does not contain `tm_yday`. It tries to calculate it
from other fields, but... as one can say it is completely wrong.
Since other fields are copied in verbatim we work around this
problem by using a less efficient method.
Fixes#85.
This is due to somewhat ambiguous semantics of `Date`. It cannot
really constructed without an intermediate `DateTime` much like
the removed `Time`, but it is much more useful than `Time` so
we need some reasonable meaning to it. This commit clarifies
that meaning and corrects some problems around it:
- The date itself is timezone-agnostic unless the timezone itself
has an offset equal to or greater than one day. In all current
time zones, the date conversion should be a no-op.
- The date may be attached some offset; that offset should have
been occurred within the corresponding day in either the local
time or the UTC.
- `TimeZone` is free to assign the offset within this constraint.
For convenience, the current `Local` time zone assumes the local
midnight or the UTC midnight.
- `DateTime<Tz>` and `Date<Tz>` is now `Copy`/`Send` when
`Tz::Offset` is `Copy`/`Send`. The implementations for them were
mistakenly omitted. Fixes#25.
- `Local::from_utc_datetime` didn't set a correct offset.
The tests for `Local` were lacking. Fixes#26.
`Time` with an associated time zone is in principle possible, but
in practice it can only meaningfully constructed from an existing
`DateTime`. this makes it hard to implement other operations
natural to `NaiveTime` for `Time` (e.g. `with_*` methods), so
we simply let it go.
migration path: if you *do* happen to use `Time`, don't panic!
every operation possible to `Time` is much more possible to
`NaiveTime`. if you have to deal with a local time, first combine
it with a `NaiveDate`, convert it via `TimeZone::from_local_datetime`
then extract `Time` part again.
- We have splitted `Offset` into `Offset` and `OffsetState` (name
changes in consideration). The former is used to construct and convert
local or UTC date, and the latter is used to store the UTC offset
inside constructed values. Some offsets are their own states as well.
- This uses lots of associated types which implementation is still in
flux. Currently it crashes with debuginfo enabled. We've temporarily
disabled debuginfo from `Cargo.toml`.
- This technically allows a conversion to the local time, but not yet
tested.
János Illés
Kang Seonghoon
Sergey V. Galtsev
Jisoo Park
Dan