Remove empty core::lazy and std::lazy
PR #98165 with commits 7c360dc117 and c1a2db3372 has moved all of the components of these modules into different places, namely {std,core}::sync and {std,core}::cell. The empty modules remained. As they are unstable, we can simply remove them.
PR #98165 with commits 7c360dc117 and c1a2db3372
has moved all of the components of these modules into different places,
namely {std,core}::sync and {std,core}::cell. The empty
modules remained. As they are unstable, we can simply remove them.
std: use futex in `Once`
Now that we have efficient locks, let's optimize the rest of `sync` as well. This PR adds a futex-based implementation for `Once`, which drastically simplifies the implementation compared to the generic version, which is provided as fallback for platforms without futex (Windows only supports them on newer versions, so it uses the fallback for now).
Instead of storing a linked list of waiters, the new implementation adds another state (`QUEUED`), which is set when there are waiting threads. These now use `futex_wait` on that state and are woken by the running thread when it finishes and notices the `QUEUED` state, thereby avoiding unnecessary calls to `futex_wake_all`.
Avoid repeated re-initialization of the BufReader buffer
Fixes https://github.com/rust-lang/rust/issues/102727
We accidentally removed this in https://github.com/rust-lang/rust/pull/98748. It looks so redundant. But it isn't.
The default `Read::read_buf` will defensively initialize the whole buffer, if any of it is indicated to be uninitialized. In uses where reads from the wrapped `Read` impl completely fill the `BufReader`, `initialized` and `filled` are the same, and this extra member isn't required. But in the reported issue, the `BufReader` wraps a `Read` impl which will _never_ fill the whole buffer. So the default `Read::read_buf` implementation repeatedly re-initializes the extra space in the buffer.
This adds back the extra `initialized` member, which ensures that the default `Read::read_buf` only zero-initialized the buffer once, and I've tried to add a comment which explains this whole situation.
unsafe keyword: trait examples and unsafe_op_in_unsafe_fn update
Having a safe `fn` in an `unsafe trait` vs an `unsafe fn` in a safe `trait` are pretty different situations, but the distinction is subtle and can confuse even seasoned Rust developers. So let's have explicit examples of both. I also removed the existing `unsafe trait` example since it was rather strange.
Also the `unsafe_op_in_unsafe_fn` lint can help disentangle the two sides of `unsafe`, so update the docs to account for that.
Add `AsFd` implementations for stdio lock types on WASI.
This mirrors the implementations on Unix platforms, and also mirrors the existing `AsRawFd` impls.
This is similar to #100892, but is for the `*Lock` types.
Update docs so that deprecated method points to relevant method
The docs for the deprecated 'park_timeout_ms' method suggests that the user 'use park_timeout' method instead (at https://doc.rust-lang.org/std/thread/index.html).
Making a similar change so that the docs for the deprecated `sleep_ms` method suggest that the user `use sleep` method instead.
Add a niche to `Duration`, unix `SystemTime`, and non-apple `Instant`
As the nanoseconds fields is always between `0` and `(NANOS_PER_SEC - 1)` inclusive, use the `rustc_layout_scalar_valid_range` attributes to create a niche in the nanosecond field of `Duration` and `Timespec` (which is used to implement unix `SystemTime` and non-apple unix `Instant`; windows `Instant` is implemented with `Duration` and therefore will also benefit). This change has the benefit of making `Option<T>` the same size as `T` for the previously mentioned types. Also shrinks the nanoseconds field of `Timespec` to a `u32` as nanoseconds do not need the extra range of an `i64`, shrinking `Timespec` by 4 bytes on 32-bit platforms.
r? ```@joshtriplett```
Make `std::os::fd` public.
`std::os::fd` defines types like `OwnedFd` and `RawFd` and is common
between Unix and non-Unix platforms that share a basic file-descriptor
concept. Rust currently uses this internally to simplify its own code,
but it would be useful for external users in the same way, so make it
public.
This means that `OwnedFd` etc. will all appear in three places, for
example on unix platforms:
- `std::os::fd::OwnedFd`
- `std::os::unix::io::OwnedFd`
- `std::os::unix::prelude::OwnedFd`
r? `````@joshtriplett`````
Suggest unwrapping `???<T>` if a method cannot be found on it but is present on `T`.
This suggests various ways to get inside wrapper types if the method cannot be found on the wrapper type, but is present on the wrappee.
For this PR, those wrapper types include `Localkey`, `MaybeUninit`, `RefCell`, `RwLock` and `Mutex`.
Stabilize bench_black_box
This PR stabilize `feature(bench_black_box)`.
```rust
pub fn black_box<T>(dummy: T) -> T;
```
The FCP was completed in https://github.com/rust-lang/rust/issues/64102.
`@rustbot` label +T-libs-api -T-libs
Stabilize `#![feature(mixed_integer_ops)]`
Tracked and FCP completed in #87840.
````@rustbot```` label +T-libs-api +S-waiting-on-review +relnotes
r? rust-lang/t-libs-api
Recover error strings on Unix from_lossy_utf8
Some language settings can result in unreliable UTF-8 being produced.
This can result in failing to emit the error string, panicking instead.
from_lossy_utf8 allows us to assume these strings usually will be fine.
This fixes rust-lang#99535.
make Condvar, Mutex, RwLock const constructors work with the `unsupported` impl
applying this patch locally to the `rust-src` component fixes#98378
however, the solution seems wrong to me because PR #97791 didn't add any `rustc_const_stable` attribute to underlying implementations like `std::sys::unix::futex`, so I must be missing something about how const-stability is checked ... maybe the `restricted_std` feature (gate?) has an effect?
fixes#98378fixes#98293 (probably)
Refactor some `std` code that works with pointer offstes
This PR replaces `pointer::offset` in standard library with `pointer::add` and `pointer::sub`, [re]moving some casts and using `.addr()` while we are at it.
This is a more complicated refactor than all other sibling PRs, so take a closer look when reviewing, please 😃 (though I've checked this multiple times and it looks fine).
r? ````@scottmcm````
_split off from #100746, continuation of #100822_
Update doc after renaming `fn is_zero`
`fn is_zero` has been renamed to `fn count_is_zero` in 1b1bf24636.
This patch updates the documentation accordingly.
Remove `RtlGenRandom` (take two)
First try to use the system preferred RNG but if that fails (e.g. due to a broken system configuration) then fallback to manually opening an algorithm handle.
This mirrors the implementations on Unix platforms, and also mirrors the
existing `AsRawFd` impls.
This is similar to #100892, but is for the `*Lock` types.
Remove use of `io::ErrorKind::Other` in std
The documentation states that this `ErrorKind` is not used by the standard library. Instead, `io::ErrorKind::Uncategorized` should be used.
The two instances are in the unstable API [linux_pidfd](https://github.com/rust-lang/rust/issues/82971).
Clarify Path::extension() semantics in docs abstract
State up-front and center what shape the returned extension will have, without making the user read through the description and examples.
This is a doc-only change. There are no changes to the API contract and the clarification is in line with what was already stated/promised in the existing doc text - just clarified, summarized, and served bright and early.
Rationale: Various frameworks and libraries for different platforms have their different conventions as to whether an "extension" is ".ext" or just "ext" and anyone that's had to deal with this ambiguity in the past is always double- or triple-checking to make sure the function call returns an extension that matches the expected semantics. Offer the answer to this important question right off the bat instead of making them dig to find it.
```@rustbot``` label +A-docs
std: use `sync::RwLock` for internal statics
Since `sync::RwLock` is now `const`-constructible, it can be used for internal statics, removing the need for `sys_common::StaticRwLock`. This adds some extra allocations on platforms which need to box their locks (currently SGX and some UNIX), but these will become unnecessary with the lock improvements tracked in #93740.
First try to use the system preferred RNG but if that fails (e.g. due to a broken system configuration) then fallback to manually opening an algorithm handle.
State up-front and center what shape the returned extension will have, without
making the user read through the description and examples.
Rationale: Various frameworks and libraries for different platforms have their
different conventions as to whether an "extension" is ".ext" or just "ext" and
anyone that's had to deal with this ambiguity in the past is always double- or
triple-checking to make sure the function call returns an extension that matches
the expected semantics. Offer the answer to this important question right off
the bat instead of making them dig to find it.
