For a while Chrono's serialization support was barely working,
i.e. usable but never been safe. While it wouldn't cause any memory
unsafety, attacker can fabricate an input that will make most users
confused (e.g. seemingly same Date which doesn't compare equally).
This commit will properly error for those cases.
It was also problematic that the generated rustc-serialize format is
very inefficient, especially for JSON. Due to the backward
compatibillity this commit does NOT fix them (likely to be in 0.3),
but this does try to define the exact format and define tons of
tests to detect any change to the serialization.
There are several remaining problems in the serialization format;
the serde implementation seems good, but it is unable to distinguish
some cases of leap seconds (practically won't matter, but still).
The rustc-serialize implementation would require a massive redesign.
For now, I postpone those issues to 0.3 (what a convenient excuse).
Fixes#42.
`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.