Since SystemTime is opaque there is no way to check if the result
of an addition will be in bounds. That makes the Add<Duration>
trait completely unusable with untrusted data. This is a big problem
because adding a Duration to UNIX_EPOCH is the standard way of
constructing a SystemTime from a unix timestamp.
This commit implements checked_add_duration(&self, &Duration) -> Option<SystemTime>
for std::time::SystemTime and as a prerequisite also for all platform
specific time structs. This also led to the refactoring of many
add_duration(&self, &Duration) -> SystemTime functions to avoid
redundancy (they now unwrap the result of checked_add_duration).
Some basic unit tests for the newly introduced function were added
too.
As a start, the port uses the simplest possible configuration (no jemalloc, abort on panic)
and makes use of existing Unix-specific code wherever possible.
It adds targets for x86_64 (current main HermitCore platform) and aarch64 (HermitCore platform
under development).
Together with the patches to "liblibc" and "llvm", this enables HermitCore applications to be
written in Rust.
When subtracting an Instant from another, the function will panick when `RHS > self`, but the error message confusingly displays a different error:
```rust
let i = Instant::now();
let other = Instant::now();
if other > i {
println!("{:?}", i - other);
}
```
This results in a panic:
```
thread 'test_instant' panicked at 'other was less than the current instant', libstd/sys/unix/time.rs:292:17
```
Following changes:
* birthtime does not exist on DragonFly
* errno: __dfly_error is no more. Use #[thread_local] static errno.
* clock_gettime expects a c_ulong (use a type alias)
These changes are required to build DragonFly snapshots again.
This code was currently only exercised on OSX, but this applies the same method
of subtraction used on Linux which doesn't have the same overflow issues.
Note that this currently includes no tests, but that's because this is only
visible with debug assertions enabled. Soon, however, I'll enable debug
assertions on all auto builds on the bots so we should get testing for this.
Closes#32268
These accessors are used to get at the last modification, last access, and
creation time of the underlying file. Currently not all platforms provide the
creation time, so that currently returns `Option`.
This commit is an implementation of [RFC 1288][rfc] which adds two new unstable
types to the `std::time` module. The `Instant` type is used to represent
measurements of a monotonically increasing clock suitable for measuring time
withing a process for operations such as benchmarks or just the elapsed time to
do something. An `Instant` favors panicking when bugs are found as the bugs are
programmer errors rather than typical errors that can be encountered.
[rfc]: https://github.com/rust-lang/rfcs/pull/1288
The `SystemTime` type is used to represent a system timestamp and is not
monotonic. Very few guarantees are provided about this measurement of the system
clock, but a fixed point in time (`UNIX_EPOCH`) is provided to learn about the
relative distance from this point for any particular time stamp.
This PR takes the same implementation strategy as the `time` crate on crates.io,
namely:
| Platform | Instant | SystemTime |
|------------|--------------------------|--------------------------|
| Windows | QueryPerformanceCounter | GetSystemTimeAsFileTime |
| OSX | mach_absolute_time | gettimeofday |
| Unix | CLOCK_MONOTONIC | CLOCK_REALTIME |
These implementations can perhaps be refined over time, but they currently
satisfy the requirements of the `Instant` and `SystemTime` types while also
being portable across implementations and revisions of each platform.
* Delete `sys::unix::{c, sync}` as these are now all folded into libc itself
* Update all references to use `libc` as a result.
* Update all references to the new flat namespace.
* Moves all windows bindings into sys::c
This commit is an implementation of [RFC 1040][rfc] which is a redesign of the
currently-unstable `Duration` type. The API of the type has been scaled back to
be more conservative and it also no longer supports negative durations.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/1040-duration-reform.md
The inner `duration` module of the `time` module has now been hidden (as
`Duration` is reexported) and the feature name for this type has changed from
`std_misc` to `duration`. All APIs accepting durations have also been audited to
take a more flavorful feature name instead of `std_misc`.
Closes#24874
This commit modifies the standard library and its dependencies to link correctly
when built against MUSL. This primarily ensures that the right libraries are
linked against and when they're linked against they're linked against
statically.
**The implementation is a direct adaptation of libcxx's
condition_variable implementation.**
pthread_cond_timedwait uses the non-monotonic system clock. It's
possible to change the clock to a monotonic via pthread_cond_attr, but
this is incompatible with static initialization. To deal with this, we
calculate the timeout using the system clock, and maintain a separate
record of the start and end times with a monotonic clock to be used for
calculation of the return value.
