Up until now, Servo was using a very old version of time to get a
cross-process monotonic timestamp (using `time::precise_time_ns()`).
This change replaces the usage of old time with a new serializable
monotonic time called `CrossProcessInstant` and uses it where `u64`
timestamps were stored before. The standard library doesn't provide this
functionality because it isn't something you can do reliably on all
platforms. The idea is that we do our best and then fall back
gracefully.
This is a big change, because Servo was using `u64` timestamps all over
the place some as raw values taken from `time::precise_time_ns()` and
some as relative offsets from the "navigation start," which is a concept
similar to DOM's `timeOrigin` (but not exactly the same). It's very
difficult to fix this situation without fixing it everywhere as the
`Instant` concept is supposed to be opaque. The good thing is that this
change clears up all ambiguity when passing times as a `time::Duration`
is unit agnostic and a `CrossProcessInstant` represents an absolute
moment in time.
The `time` version of `Duration` is used because it can both be negative
and is also serializable.
Good things:
- No need too pass around `time` and `time_precise` any longer.
`CrossProcessInstant` is also precise and monotonic.
- The distinction between a time that is unset or at `0` (at some kind
of timer epoch) is now gone.
There still a lot of work to do to clean up timing, but this is the
first step. In general, I've tried to preserve existing behavior, even
when not spec compliant, as much as possible. I plan to submit followup
PRs fixing some of the issues I've noticed.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Remove the `ucd` dependency which has not been updated in 8 years. In
addition, replace it with a generated UnicodeBlock enum which reflects
the modern Unicode standard. This is generated via a Python script which
is included in the repository. The generation is not part of the build
process, because the Unicode database is hosted on the web and it does
not change the frequently.
This is done instead of bringing in the more up-to-date `unicode_blocks`
dependency. `unicode_blocks` defines each block as constant, which means
that they cannot be used in match statements -- which we do in Servo.
Co-authored-by: Lauryn Menard <lauryn.menard@gmail.com>
For a long time, `gfx_traits` has held a lot of things unrelated to graphics
and also unrelated to the `gfx` crate (which is mostly about fonts).
This is a cleanup which does a few things:
1. Move non `gfx` crate things out of `gfx_traits`. This is important in
order to prevent dependency cycles with a different integration between
layout, script, and fonts.
2. Rename the `msg` crate to `base`. It didn't really contain anything
to do with messages and instead mostly holds ids, which are used
across many different crates in Servo. This new crate will hold the
*rare* data types that are widely used.
Details:
- All BackgroundHangMonitor-related things from base to a new
`background_hang_monitor_api` crate.
- Moved `TraversalDirection` to `script_traits`
- Moved `Epoch`-related things from `gfx_traits` to `base`.
- Moved `PrintTree` to base. This should be widely useful in Servo.
- Moved `WebrenderApi` from `base` to `webrender_traits` and renamed it
to `WebRenderFontApi`.
