Commit Graph

1058 Commits

Author SHA1 Message Date
Ashley Mannix
d65cb6ebce deprecate atomic::spin_loop_hint in favour of hint::spin_loop 2021-01-13 16:30:29 +10:00
Dylan DPC
e73ee1dde2
Rollup merge of #80736 - KodrAus:feat/lazy-resolve, r=dtolnay
use Once instead of Mutex to manage capture resolution

For #78299

This allows us to return borrows of the captured backtrace frames that are tied to a borrow of the Backtrace itself, instead of to some short-lived Mutex guard.

We could alternatively share `&Mutex<Capture>`s and lock on-demand, but then we could potentially forget to call `resolve()` before working with the capture. It also makes it semantically clearer what synchronization is needed on the capture.

cc `@seanchen1991` `@rust-lang/project-error-handling`
2021-01-13 03:20:17 +01:00
Camelid
7463292015 Add docs on performance 2021-01-11 19:18:39 -08:00
Steven Fackler
e6c07b0628 clarify docs a bit 2021-01-11 17:16:44 -05:00
Steven Fackler
5cb830397e make check a bit more clear 2021-01-11 17:13:50 -05:00
Steven Fackler
a9ef7983a6 clean up control flow 2021-01-11 07:48:24 -05:00
Steven Fackler
ebe402dc9e Fix handling of malicious Readers in read_to_end 2021-01-11 07:27:03 -05:00
bors
34628e5b53 Auto merge of #80867 - JohnTitor:rollup-tvqw555, r=JohnTitor
Rollup of 9 pull requests

Successful merges:

 - #79502 (Implement From<char> for u64 and u128.)
 - #79968 (Improve core::ptr::drop_in_place debuginfo)
 - #80774 (Fix safety comment)
 - #80801 (Use correct span for structured suggestion)
 - #80803 (Remove useless `fill_in` function)
 - #80820 (Support `download-ci-llvm` on NixOS)
 - #80825 (Remove under-used ImplPolarity enum)
 - #80850 (Allow #[rustc_builtin_macro = "name"])
 - #80857 (Add comment to `Vec::truncate` explaining `>` vs `>=`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
2021-01-10 08:01:12 +00:00
Yuki Okushi
d64356f06c
Rollup merge of #80774 - LingMan:patch-1, r=nagisa
Fix safety comment

The size assertion in the comment was inverted compared to the code. After fixing that the implication that `(new_size >= old_size) => new_size != 0` still doesn't hold so explain why `old_size != 0` at this point.
2021-01-10 16:55:57 +09:00
bors
7a193921a0 Auto merge of #77862 - danielhenrymantilla:rustdoc/fix-macros_2_0-paths, r=jyn514,petrochenkov
Rustdoc: Fix macros 2.0 and built-in derives being shown at the wrong path

Fixes #74355

  - ~~waiting on author + draft PR since my code ought to be cleaned up _w.r.t._ the way I avoid the `.unwrap()`s:~~

      - ~~dummy items may avoid the first `?`,~~

      - ~~but within the module traversal some tests did fail (hence the second `?`), meaning the crate did not possess the exact path of the containing module (`extern` / `impl` blocks maybe? I'll look into that).~~

r? `@jyn514`
2021-01-10 05:15:01 +00:00
bors
1f9dc9a182 Auto merge of #80755 - sunfishcode:path-cleanup/copy, r=nagisa
Optimize away some path lookups in the generic `fs::copy` implementation

This also eliminates a use of a `Path` convenience function, in support
of #80741, refactoring `std::path` to focus on pure data structures and
algorithms.
2021-01-09 07:48:53 +00:00
bors
8f0b945cfc Auto merge of #77853 - ijackson:slice-strip-stab, r=Amanieu
Stabilize slice::strip_prefix and slice::strip_suffix

These two methods are useful.  The corresponding methods on `str` are already stable.

I believe that stablising these now would not get in the way of, in the future, extending these to take a richer pattern API a la `str`'s patterns.

Tracking PR: #73413.  I also have an outstanding PR to improve the docs for these two functions and the corresponding ones on `str`: #75078

I have tried to follow the [instructions in the dev guide](https://rustc-dev-guide.rust-lang.org/stabilization_guide.html#stabilization-pr).  The part to do with `compiler/rustc_feature` did not seem applicable.  I assume that's because these are just library features, so there is no corresponding machinery in rustc.
2021-01-07 15:21:30 +00:00
LingMan
769fb8a8b7
Fix safety comment
The size assertion in the comment was inverted compared to the code. After fixing that the implication that `(new_size >= old_size) => new_size != 0` still doesn't hold so explain why `old_size != 0` at this point.
2021-01-07 09:13:21 +01:00
Yuki Okushi
6275a29dbe Update compiler_builtins to 0.1.39 2021-01-07 16:16:36 +09:00
Dan Gohman
97baac4184 Optimize away some path lookups in the generic fs::copy implementation.
This also eliminates a use of a `Path` convenience function, in support
of #80741, refactoring `std::path` to focus on pure data structures and
algorithms.
2021-01-06 08:36:31 -08:00
Daniel Henry-Mantilla
aa863caebe Style nit: replace for_each & return with for & continue
Co-Authored-By: Joshua Nelson <jyn514@gmail.com>
2021-01-06 15:13:38 +01:00
Camelid
25a4964191 Use heading for std::prelude and not io::prelude
The heading style for `std::prelude` is to be consistent with the
headings for `std` and `core`: `# The Rust Standard Library` and
`# The Rust Core Library`, respectively.
2021-01-05 17:52:24 -08:00
Camelid
4274ba40bd Use lowercase for prelude items 2021-01-05 17:51:27 -08:00
Ashley Mannix
db4585aa3b use Once instead of Mutex to manage capture resolution
This allows us to return borrows of the captured backtrace frames
that are tied to a borrow of the Backtrace itself, instead of to
some short-lived Mutex guard.

It also makes it semantically clearer what synchronization is needed
on the capture.
2021-01-06 10:44:06 +10:00
Ian Jackson
dea6d6c909 BufWriter::into_raw_parts: Add tracking issue number
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2021-01-04 15:35:28 +00:00
bors
bcd6975079 Auto merge of #80590 - camelid:bool-never-docs, r=nagisa
Update `bool` and `!` docs
2021-01-03 12:21:12 +00:00
Camelid
4e767596e2
always demands -> requires 2021-01-01 18:55:01 -08:00
Camelid
4af11126a8
Update bool and ! docs 2021-01-01 10:09:56 -08:00
Camelid
0506789014 Remove many unnecessary manual link resolves from library
Now that #76934 has merged, we can remove a lot of these! E.g, this is
no longer necessary:

    [`Vec<T>`]: Vec
2020-12-31 11:54:32 -08:00
Camelid
588786a788 Add error docs 2020-12-30 11:44:03 -08:00
Camelid
4ee6d1bf54 Add description independent of Read::read_to_string 2020-12-30 11:35:17 -08:00
bors
e226704685 Auto merge of #80511 - Mark-Simulacrum:bump-stage0, r=pietroalbini
Bump bootstrap compiler to 1.50 beta

r? `@pietroalbini`
2020-12-30 18:32:31 +00:00
Mark Rousskov
fe031180d0 Bump bootstrap compiler to 1.50 beta 2020-12-30 09:27:19 -05:00
Yuki Okushi
00741b8810
Rollup merge of #80260 - RalfJung:less-untyped-panics, r=m-ou-se
slightly more typed interface to panic implementation

The panic payload is currently being passed around as a `usize`. However, it actually is a pointer, and the involved types are available on all ends of this API, so I propose we use the proper pointer type to avoid some casts. Avoiding int-to-ptr casts also makes this code work with `miri -Zmiri-track-raw-pointers`.
2020-12-30 22:49:17 +09:00
BlackHoleFox
5449a42a1c Fix small typo in time comment 2020-12-29 02:10:29 -06:00
Konrad Borowski
9e779986aa Add "length" as doc alias to len methods 2020-12-28 09:13:46 +01:00
bors
257becbfe4 Auto merge of #80181 - jyn514:intra-doc-primitives, r=Manishearth
Fix intra-doc links for non-path primitives

This does *not* currently work for associated items that are
auto-implemented by the compiler (e.g. `never::eq`), because they aren't
present in the source code. I plan to fix this in a follow-up PR.

Fixes https://github.com/rust-lang/rust/issues/63351 using the approach mentioned in https://github.com/rust-lang/rust/issues/63351#issuecomment-683352130.

r? `@Manishearth`

cc `@petrochenkov` - this makes `rustc_resolve::Res` public, is that ok? I'd just add an identical type alias in rustdoc if not, which seems a waste.
2020-12-27 18:55:33 +00:00
Ian Jackson
274e2993cb Stablize slice::strip_prefix and strip_suffix, with SlicePattern
We hope later to extend `core::str::Pattern` to slices too, perhaps as
part of stabilising that.  We want to minimise the amount of type
inference breakage when we do that, so we don't want to stabilise
strip_prefix and strip_suffix taking a simple `&[T]`.

@KodrAus suggested the approach of introducing a new perma-unstable
trait, which reduces this future inference break risk.

I found it necessary to make two impls of this trait, as the unsize
coercion don't apply when hunting for trait implementations.

Since SlicePattern's only method returns a reference, and the whole
trait is just a wrapper for slices, I made the trait type be the
non-reference type [T] or [T;N] rather than the reference.  Otherwise
the trait would have a lifetime parameter.

I marked both the no-op conversion functions `#[inline]`.  I'm not
sure if that is necessary but it seemed at the very least harmless.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2020-12-27 00:50:46 +00:00
David Adler
7adeb710fb Use the hashbrown::{HashMap,HashSet} clone_from impls. 2020-12-26 19:39:38 -05:00
Ralf Jung
1600f7d693 fix another comment, and make __rust_start_panic code a bit more semantically clear 2020-12-25 23:37:27 +01:00
Dylan DPC
21d36e0daf
Rollup merge of #79213 - yoshuawuyts:stabilize-slice-fill, r=m-ou-se
Stabilize `core::slice::fill`

Tracking issue https://github.com/rust-lang/rust/issues/70758

Stabilizes the `core::slice::fill` API in Rust 1.50, adding a `memset` doc alias so people coming from C/C++ looking for this operation can find it in the docs. This API hasn't seen any changes since we changed the signature in https://github.com/rust-lang/rust/pull/71165/, and it seems like the right time to propose stabilization. Thanks!

r? `@m-ou-se`
2020-12-25 03:39:31 +01:00
Joshua Nelson
8842c1ccf3 Fix new ambiguity in the standard library
This caught several bugs where people expected `slice` to link to the
primitive, but it linked to the module instead.

This also uses `cfg_attr(bootstrap)` since the ambiguity only occurs
when compiling with stage 1.
2020-12-22 11:45:23 -05:00
Ralf Jung
7524eb2704 update a seemingly outdated comment 2020-12-22 12:49:59 +01:00
Linus Färnstrand
454f3ed902
Update library/std/src/sys/windows/thread_parker.rs
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
2020-12-22 12:33:11 +01:00
Linus Färnstrand
865e4797df Fix compare_and_swap in Windows thread_parker 2020-12-22 12:24:17 +01:00
Linus Färnstrand
427996a286 Fix documentation typo 2020-12-22 12:19:46 +01:00
Linus Färnstrand
828d4ace4d Migrate standard library away from compare_and_swap 2020-12-22 12:19:46 +01:00
Yoshua Wuyts
c2281cc189 Stabilize core::slice::fill 2020-12-22 00:16:04 +01:00
Ralf Jung
29bed26036 slightly more typed interface to panic implementation 2020-12-21 13:37:59 +01:00
Ashley Mannix
bbf5001b94
bump stabilization to 1.51.0 2020-12-21 18:40:34 +10:00
bors
15d1f81196 Auto merge of #80253 - Dylan-DPC:rollup-bkmn74z, r=Dylan-DPC
Rollup of 11 pull requests

Successful merges:

 - #80159 (Add array search aliases)
 - #80166 (Edit rustc_middle docs)
 - #80170 (Fix ICE when lookup method in trait for type that have bound vars)
 - #80171 (Edit rustc_middle::ty::TyKind docs)
 - #80199 (also const-check FakeRead)
 - #80211 (Handle desugaring in impl trait bound suggestion)
 - #80236 (Use pointer type in AtomicPtr::swap implementation)
 - #80239 (Update Clippy)
 - #80240 (make sure installer only creates directories in DESTDIR)
 - #80244 (Cleanup markdown span handling)
 - #80250 (Minor cleanups in LateResolver)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
2020-12-21 04:08:35 +00:00
Dylan DPC
635ea920f1
Rollup merge of #80159 - jyn514:array, r=m-ou-se
Add array search aliases

Missed this in https://github.com/rust-lang/rust/pull/80068. This one will really fix https://github.com/rust-lang/rust/issues/46075.

The last alias especially I'm a little unsure about - maybe fuzzy search should be fixed in rustdoc instead? Happy to make that change although I'd have to figure out how.

r? ``@m-ou-se`` although cc ``@GuillaumeGomez`` for the search issue.
2020-12-21 02:47:33 +01:00
bors
c8135455c4 Auto merge of #80088 - operutka:fix-cmsg-len-uclibc, r=dtolnay
Fix failing build of std on armv5te-unknown-linux-uclibceabi due to missing cmsg_len_zero

I'm getting the following error when trying to build `std` on `armv5te-unknown-linux-uclibceabi`:

```
error[E0425]: cannot find value `cmsg_len_zero` in this scope
   --> /home/operutka/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/ext/net/ancillary.rs:376:47
    |
376 |             let data_len = (*cmsg).cmsg_len - cmsg_len_zero;
    |                                               ^^^^^^^^^^^^^ not found in this scope
```

Obviously, this branch:
```rust
cfg_if::cfg_if! {
    if #[cfg(any(target_os = "android", all(target_os = "linux", target_env = "gnu")))] {
        let cmsg_len_zero = libc::CMSG_LEN(0) as libc::size_t;
    } else if #[cfg(any(
                  target_os = "dragonfly",
                  target_os = "emscripten",
                  target_os = "freebsd",
                  all(target_os = "linux", target_env = "musl",),
                  target_os = "netbsd",
                  target_os = "openbsd",
              ))] {
        let cmsg_len_zero = libc::CMSG_LEN(0) as libc::socklen_t;
    }
}
```

does not cover the case `all(target_os = "linux", target_env = "uclibc")`.
2020-12-21 01:16:20 +00:00
bors
b0e5c7d1fe Auto merge of #74699 - notriddle:fd-non-negative, r=m-ou-se
Mark `-1` as an available niche for file descriptors

Based on discussion from <https://internals.rust-lang.org/t/can-the-standard-library-shrink-option-file/12768>, the file descriptor `-1` is chosen based on the POSIX API designs that use it as a sentinel to report errors. A bigger niche could've been chosen, particularly on Linux, but would not necessarily be portable.

This PR also adds a test case to ensure that the -1 niche (which is kind of hacky and has no obvious test case) works correctly. It requires the "upper" bound, which is actually -1, to be expressed in two's complement.
2020-12-20 16:36:23 +00:00
Mara Bos
094b1da3a1
Check that c_int is i32 in FileDesc::new. 2020-12-20 11:56:51 +00:00
Camelid
1f9a8a1620 Add a std::io::read_to_string function
The equivalent of `std::fs::read_to_string`, but generalized to all
`Read` impls.

As the documentation on `std::io::read_to_string` says, the advantage of
this function is that it means you don't have to create a variable first
and it provides more type safety since you can only get the buffer out
if there were no errors. If you use `Read::read_to_string`, you have to
remember to check whether the read succeeded because otherwise your
buffer will be empty.

It's friendlier to newcomers and better in most cases to use an explicit
return value instead of an out parameter.
2020-12-19 21:46:40 -08:00
bors
c1d5843661 Auto merge of #79473 - m-ou-se:clamp-in-core, r=m-ou-se
Move {f32,f64}::clamp to core.

`clamp` was recently stabilized (tracking issue: https://github.com/rust-lang/rust/issues/44095). But although `Ord::clamp` was added in `core` (because `Ord` is in `core`), the versions for the `f32` and `f64` primitives were added in `std` (together with `floor`, `sin`, etc.), not in `core` (together with `min`, `max`, `from_bits`, etc.).

This change moves them to `core`, such that `clamp` on floats is available in `no_std` programs as well.
2020-12-19 21:57:38 +00:00
bors
bd2f1cb278 Auto merge of #79342 - CDirkx:ipaddr-const, r=oli-obk
Stabilize all stable methods of `Ipv4Addr`, `Ipv6Addr` and `IpAddr` as const

This PR stabilizes all currently stable methods of `Ipv4Addr`, `Ipv6Addr` and `IpAddr` as const.
Tracking issue: #76205

`Ipv4Addr` (`const_ipv4`):
 - `octets`
 - `is_loopback`
 - `is_private`
 - `is_link_local`
 - `is_multicast`
 - `is_broadcast`
 - `is_docmentation`
 - `to_ipv6_compatible`
 - `to_ipv6_mapped`

`Ipv6Addr` (`const_ipv6`):
 - `segments`
 - `is_unspecified`
 - `is_loopback`
 - `is_multicast`
 - `to_ipv4`

`IpAddr` (`const_ip`):
 - `is_unspecified`
 - `is_loopback`
 - `is_multicast`

## Motivation
The ip methods seem like prime candidates to be made const: their behavior is defined by an external spec, and based solely on the byte contents of an address. These methods have been made unstable const in the beginning of September, after the necessary const integer arithmetic was stabilized.

There is currently a PR open (#78802) to change the internal representation of `IpAddr{4,6}` from `libc` types to a byte array. This does not have any impact on the constness of the methods.

## Implementation
Most of the stabilizations are straightforward, with the exception of `Ipv6Addr::segments`, which uses the unstable feature `const_fn_transmute`. The code could be rewritten to equivalent stable code, but this leads to worse code generation (#75085).
This is why `segments` gets marked with `#[rustc_allow_const_fn_unstable(const_fn_transmute)]`, like the already const-stable `Ipv6Addr::new`, the justification being that a const-stable alternative implementation exists https://github.com/rust-lang/rust/pull/76206#issuecomment-685044184.

## Future posibilities
This PR const-stabilizes all currently stable ip methods, however there are also a number of unstable methods under the `ip` feature (#27709). These methods are already unstable const. There is a PR open (#76098) to stabilize those methods, which could include const-stabilization. However, stabilizing those methods as const is dependent on `Ipv4Addr::octets` and `Ipv6Addr::segments` (covered by this PR).
2020-12-19 13:13:41 +00:00
Yuki Okushi
dbcf659dce
Rollup merge of #80068 - jyn514:mut-reference, r=m-ou-se
Add `&mut` as an alias for 'reference' primitive

Closes https://github.com/rust-lang/rust/issues/46075.
2020-12-19 15:16:05 +09:00
Yuki Okushi
60aad47c13
Rollup merge of #79211 - yoshuawuyts:future-doc-alias, r=Mark-Simulacrum
Add the "async" and "promise" doc aliases to `core::future::Future`

Adds the "async" and "promise" doc aliases to `core::future::Future`. This enables people who search for "async" or "promise" to find `Future`, which is Rust's core primitive for async programming. Thanks!
2020-12-19 15:16:01 +09:00
Yuki Okushi
0765536c0b
Rollup merge of #78083 - ChaiTRex:master, r=m-ou-se
Stabilize or_insert_with_key

Stabilizes the `or_insert_with_key` feature from https://github.com/rust-lang/rust/issues/71024. This allows inserting key-derived values when a `HashMap`/`BTreeMap` entry is vacant.

The difference between this and  `.or_insert_with(|| ... )` is that this provides a reference to the key to the closure after it is moved with `.entry(key_being_moved)`, avoiding the need to copy or clone the key.
2020-12-19 15:15:57 +09:00
Camelid
4a6014bc28 Use heading style for 'The I/O Prelude' in std::io::prelude 2020-12-18 15:05:15 -08:00
Camelid
c78bfbae28 Use consistent punctuation for 'Prelude contents' docs 2020-12-18 15:05:14 -08:00
Corey Farwell
3ea744e2ac Recommend panic::resume_unwind instead of panicking.
Fixes https://github.com/rust-lang/rust/issues/79950.
2020-12-18 17:03:45 -05:00
Joshua Nelson
f2743a5db7 Add array search aliases 2020-12-18 11:56:07 -05:00
Yoshua Wuyts
48d5874914 Add the "promise" aliases to the async lang feature 2020-12-18 16:27:09 +01:00
Ralf Jung
441a33e81b
Rollup merge of #80147 - pierwill:patch-9, r=lcnr
Add missing punctuation to std::alloc docs

Add a period to first line of module docs to match other modules in std.
2020-12-18 16:22:14 +01:00
Ralf Jung
5bcbd0f5c1
Rollup merge of #80146 - pierwill:pierwill-prelude-mod-docs, r=lcnr
Edit formatting in Rust Prelude docs

Use consistent punctuation and capitalization in the list of things re-exported in the prelude.

Also adds a (possibly missing) word.
2020-12-18 16:22:13 +01:00
bors
6340607aca Auto merge of #79485 - EllenNyan:stabilize_unsafe_cell_get_mut, r=m-ou-se
Stabilize `unsafe_cell_get_mut`

Tracking issue: #76943

r? `@m-ou-se`
2020-12-18 11:39:26 +00:00
pierwill
9cb43bd994
Add missing punctuation to std::alloc docs
Add a period to first line of module docs to match other modules in std.
2020-12-17 21:49:32 -08:00
pierwill
ea338f5443 Edit formatting in Rust Prelude docs
Use consistent punctuation and capitalization in the list
of things re-exported in the prelude.

Also adds a (possibly missing) word.
2020-12-17 21:22:58 -08:00
Ondrej Perutka
ec078155f1 Fix failing build of std on armv5te-unknown-linux-uclibceabi due to missing cmsg_len_zero 2020-12-16 20:34:21 +01:00
Joshua Nelson
8fb553c7da Add &mut as an alias for 'reference' primitive 2020-12-15 20:22:12 -05:00
bors
c00a4648a4 Auto merge of #78833 - CDirkx:parse_prefix, r=dtolnay
Refactor and fix `parse_prefix` on Windows

This PR is an extension of #78692 as well as a general refactor of `parse_prefix`:

**Fixes**:
There are two errors in the current implementation of `parse_prefix`:

Firstly, in the current implementation only `\` is recognized as a separator character in device namespace prefixes. This behavior is only correct for verbatim paths; `"\\.\C:/foo"` should be parsed as `"C:"` instead of `"C:/foo"`.

Secondly, the current implementation only handles single separator characters. In non-verbatim paths a series of separator characters should be recognized as a single boundary, e.g. the UNC path `"\\localhost\\\\\\C$\foo"` should be parsed as `"\\localhost\\\\\\C$"` and then `UNC(server: "localhost", share: "C$")`, but currently it is not parsed at all, because it starts being parsed as `\\localhost\` and then has an invalid empty share location.

Paths like `"\\.\C:/foo"` and `"\\localhost\\\\\\C$\foo"` are valid on Windows, they are equivalent to just `"C:\foo"`.

**Refactoring**:
All uses of `&[u8]` within `parse_prefix` are extracted to helper functions and`&OsStr` is used instead. This reduces the number of places unsafe is used:
- `get_first_two_components` is adapted to the more general `parse_next_component` and used in more places
- code for parsing drive prefixes is extracted to `parse_drive`
2020-12-16 00:47:50 +00:00
bors
fa41639427 Auto merge of #77618 - fusion-engineering-forks:windows-parker, r=Amanieu
Add fast futex-based thread parker for Windows.

This adds a fast futex-based thread parker for Windows. It either uses WaitOnAddress+WakeByAddressSingle or NT Keyed Events (NtWaitForKeyedEvent+NtReleaseKeyedEvent), depending on which is available. Together, this makes this thread parker work for Windows XP and up. Before this change, park()/unpark() did not work on Windows XP: it needs condition variables, which only exist since Windows Vista.

---

Unfortunately, NT Keyed Events are an undocumented Windows API. However:
- This API is relatively simple with obvious behaviour, and there are several (unofficial) articles documenting the details. [1]
- parking_lot has been using this API for years (on Windows versions before Windows 8). [2] Many big projects extensively use parking_lot, such as servo and the Rust compiler itself.
- It is the underlying API used by Windows SRW locks and Windows critical sections. [3] [4]
- The source code of the implementations of Wine, ReactOs, and Windows XP are available and match the expected behaviour.
- The main risk with an undocumented API is that it might change in the future. But since we only use it for older versions of Windows, that's not a problem.
- Even if these functions do not block or wake as we expect (which is unlikely, see all previous points), this implementation would still be memory safe. The NT Keyed Events API is only used to sleep/block in the right place.

[1]\: http://www.locklessinc.com/articles/keyed_events/
[2]\: https://github.com/Amanieu/parking_lot/commit/43abbc964e
[3]\: https://docs.microsoft.com/en-us/archive/msdn-magazine/2012/november/windows-with-c-the-evolution-of-synchronization-in-windows-and-c
[4]\: Windows Internals, Part 1, ISBN 9780735671300

---

The choice of fallback API is inspired by parking_lot(_core), but the implementation of this thread parker is different. While parking_lot has no use for a fast path (park() directly returning if unpark() was already called), this implementation has a fast path that returns without even checking which waiting/waking API to use, as the same atomic variable with compatible states is used in all cases.
2020-12-14 16:41:14 +00:00
Guillaume Gomez
5d8b2a5bf1
Rollup merge of #79918 - woodruffw-forks:ww/doc-initializer-side-effects, r=dtolnay
doc(array,vec): add notes about side effects when empty-initializing

Copying some context from a conversation in the Rust discord:

* Both `vec![T; 0]` and `[T; 0]` are syntactically valid, and produce empty containers of their respective types

* Both *also* have side effects:

```rust
fn side_effect() -> String {
    println!("side effect!");

    "foo".into()
}

fn main() {
    println!("before!");

    let x = vec![side_effect(); 0];

    let y = [side_effect(); 0];

    println!("{:?}, {:?}", x, y);
}
```

produces:

```
before!
side effect!
side effect!
[], []
```

This PR just adds two small notes to each's documentation, warning users that side effects can occur.

I've also submitted a clippy proposal: https://github.com/rust-lang/rust-clippy/issues/6439
2020-12-14 14:43:44 +01:00
Yuki Okushi
d559bb6707
Rollup merge of #79398 - pickfire:keyword, r=Dylan-DPC
Link loop/for keyword

Even though the reference already have all of these, I am just adding related keywords in the see also to let others easily click on the related keyword.
2020-12-13 11:05:30 +09:00
Ian Jackson
79c72f57d5 fixup! WriterPanicked: Use debug_struct 2020-12-12 18:39:30 +00:00
Ian Jackson
5ac431fb08
WriterPanicked: Use debug_struct
Co-authored-by: Ivan Tham <pickfire@riseup.net>
2020-12-12 13:37:29 +00:00
Ian Jackson
7fab9cb8ac bufwriter::WriterPanicked: Provide panicking example
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
2020-12-12 12:34:48 +00:00
William Woodruff
d986924eb1
doc: apply suggestions 2020-12-11 10:09:40 -05:00
bors
a2e29d67c2 Auto merge of #79893 - RalfJung:forget-windows, r=oli-obk
Windows TLS: ManuallyDrop instead of mem::forget

The Windows TLS implementation still used `mem::forget` instead of `ManuallyDrop`, leading to the usual problem of "using" the `Box` when it should not be used any more.
2020-12-11 07:54:35 +00:00
Tyler Mandry
17ec4b8258
Rollup merge of #79809 - Eric-Arellano:split-once, r=matklad
Dogfood `str_split_once()`

Part of https://github.com/rust-lang/rust/issues/74773.

Beyond increased clarity, this fixes some instances of a common confusion with how `splitn(2)` behaves: the first element will always be `Some()`, regardless of the delimiter, and even if the value is empty.

Given this code:

```rust
fn main() {
    let val = "...";
    let mut iter = val.splitn(2, '=');
    println!("Input: {:?}, first: {:?}, second: {:?}", val, iter.next(), iter.next());
}
```

We get:

```
Input: "no_delimiter", first: Some("no_delimiter"), second: None
Input: "k=v", first: Some("k"), second: Some("v")
Input: "=", first: Some(""), second: Some("")
```

Using `str_split_once()` makes more clear what happens when the delimiter is not found.
2020-12-10 21:33:08 -08:00
Tyler Mandry
a8c19e1b48
Rollup merge of #79375 - vext01:kernel-copy-temps, r=bjorn3
Make the kernel_copy tests more robust/concurrent.

These tests write to the same filenames in /tmp and in some cases these files don't get cleaned up properly. This caused issues for us when different users run the tests on the same system, e.g.:

```
---- sys::unix::kernel_copy::tests::bench_file_to_file_copy stdout ----
thread 'sys::unix::kernel_copy::tests::bench_file_to_file_copy' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 13, kind: PermissionDenied, message: "Permission denied" }', library/std/src/sys/unix/kernel_copy/tests.rs:71:10
---- sys::unix::kernel_copy::tests::bench_file_to_socket_copy stdout ----
thread 'sys::unix::kernel_copy::tests::bench_file_to_socket_copy' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 13, kind: PermissionDenied, message: "Permission denied" }', library/std/src/sys/unix/kernel_copy/tests.rs💯10
```

Use `std::sys_common::io__test::tmpdir()` to solve this.

CC ``@the8472.``
2020-12-10 21:33:02 -08:00
Tyler Mandry
1b4ffe4705
Rollup merge of #77027 - termhn:mul_add_doc_change, r=m-ou-se
Improve documentation for `std::{f32,f64}::mul_add`

Makes it more clear that performance improvement is not guaranteed when using FMA, even when the target architecture supports it natively.
2020-12-10 21:32:59 -08:00
bors
8cef65fde3 Auto merge of #77801 - fusion-engineering-forks:pin-mutex, r=Mark-Simulacrum
Enforce no-move rule of ReentrantMutex using Pin and fix UB in stdio

A `sys_common::ReentrantMutex` may not be moved after initializing it with `.init()`. This was not enforced, but only stated as a requirement in the comments on the unsafe functions. This change enforces this no-moving rule using `Pin`, by changing `&self` to a `Pin` in the `init()` and `lock()` functions.

This uncovered a bug I introduced in #77154: stdio.rs (the only user of ReentrantMutex) called `init()` on its ReentrantMutexes while constructing them in the intializer of `SyncOnceCell::get_or_init`, which would move them afterwards. Interestingly, the ReentrantMutex unit tests already had the same bug, so this invalid usage has been tested on all (CI-tested) platforms for a long time. Apparently this doesn't break badly on any of the major platforms, but it does break the rules.\*

To be able to keep using SyncOnceCell, this adds a `SyncOnceCell::get_or_init_pin` function, which makes it possible to work with pinned values inside a (pinned) SyncOnceCell. Whether this function should be public or not and what its exact behaviour and interface should be if it would be public is something I'd like to leave for a separate issue or PR. In this PR, this function is internal-only and marked with `pub(crate)`.

\* Note: That bug is now included in 1.48, while this patch can only make it to ~~1.49~~ 1.50. We should consider the implications of 1.48 shipping with a wrong usage of `pthread_mutex_t` / `CRITICAL_SECTION` / .. which technically invokes UB according to their specification. The risk is very low, considering the objects are not 'used' (locked) before the move, and the ReentrantMutex unit tests have verified this works fine in practice.

Edit: This has been backported and included in 1.48. And soon 1.49 too.

---

In future changes, I want to push this usage of Pin further inside `sys` instead of only `sys_common`, and apply it to all 'unmovable' objects there (`Mutex`, `Condvar`, `RwLock`). Also, while `sys_common`'s mutexes and condvars are already taken care of by #77147 and #77648, its `RwLock` should still be made movable or get pinned.
2020-12-10 23:43:20 +00:00
William Woodruff
9cf2516251
doc(array,vec): add notes about side effects when empty-initializing 2020-12-10 17:47:28 -05:00
Michael Howell
08b70eda2c Fix fd test case 2020-12-10 15:05:22 -07:00
Michael Howell
a50811a214 Add safety note to library/std/src/sys/unix/fd.rs
Co-authored-by: Elichai Turkel <elichai.turkel@gmail.com>
2020-12-10 13:31:52 -07:00
Michael Howell
59abdb6a7e Mark -1 as an available niche for file descriptors
Based on discussion from https://internals.rust-lang.org/t/can-the-standard-library-shrink-option-file/12768,
the file descriptor -1 is chosen based on the POSIX API designs that use it as a sentinel to report errors.
A bigger niche could've been chosen, particularly on Linux, but would not necessarily be portable.

This PR also adds a test case to ensure that the -1 niche
(which is kind of hacky and has no obvious test case) works correctly.
It requires the "upper" bound, which is actually -1, to be expressed in two's complement.
2020-12-10 13:31:52 -07:00
Ralf Jung
594b451ccc Windows TLS: ManuallyDrop instead of mem::forget 2020-12-10 11:07:39 +01:00
bors
e413d89aa7 Auto merge of #79274 - the8472:probe-eperm, r=nagisa
implement better availability probing for copy_file_range

Followup to https://github.com/rust-lang/rust/pull/75428#discussion_r469616547

Previously syscall detection was overly pessimistic. Any attempt to copy to an immutable file (EPERM) would disable copy_file_range support for the whole process.

The change tries to copy_file_range on invalid file descriptors which will never run into the immutable file case and thus we can clearly distinguish syscall availability.
2020-12-10 03:11:27 +00:00
The8472
7647d03c33 Improve comment grammar 2020-12-09 21:31:37 +01:00
The8472
028754a2f7 implement better availability probing for copy_file_range
previously any attempt to copy to an immutable file (EPERM) would disable
copy_file_range support for the whole process.
2020-12-09 21:31:37 +01:00
bors
f0f68778f7 Auto merge of #77611 - oli-obk:atomic_miri_leakage, r=nagisa
Directly use raw pointers in `AtomicPtr` store/load

I was unable to find any reason for this limitation in the latest source of LLVM or in the documentation [here](http://llvm.org/docs/Atomics.html#libcalls-atomic).

fixes https://github.com/rust-lang/miri/issues/1574
2020-12-09 19:53:23 +00:00
bors
c16d52db77 Auto merge of #79387 - woodruffw-forks:ww/peer-cred-pid-macos, r=Amanieu
ext/ucred: Support PID in peer creds on macOS

This is a follow-up to https://github.com/rust-lang/rust/pull/75148 (RFC: https://github.com/rust-lang/rust/issues/42839).

The original PR used `getpeereid` on macOS and the BSDs, since they don't (generally) support the `SO_PEERCRED` mechanism that Linux supplies.

This PR splits the macOS/iOS implementation of `peer_cred()` from that of the BSDs, since macOS supplies the `LOCAL_PEERPID` sockopt as a source of the missing PID. It also adds a `cfg`-gated tests that ensures that platforms with support for PIDs in `UCred` have the expected data.
2020-12-09 17:27:35 +00:00
bors
2c56ea38b0 Auto merge of #78768 - mzabaluev:optimize-buf-writer, r=cramertj
Use is_write_vectored to optimize the write_vectored implementation for BufWriter

In case when the underlying writer does not have an efficient implementation `write_vectored`, the present implementation of
`write_vectored` for `BufWriter` may still forward vectored writes directly to the writer depending on the total length of the data. This misses the advantage of buffering, as the actually written slice may be small.

Provide an alternative code path for the non-vectored case, where the slices passed to `BufWriter` are coalesced in the buffer before being flushed to the underlying writer with plain `write` calls. The buffer is only bypassed if an individual slice's length is at least as large as the buffer.

Remove a FIXME comment referring to #72919 as the issue has been closed with an explanation provided.
2020-12-09 01:54:08 +00:00
Mara Bos
67c18fdec5 Use Pin for the 'don't move' requirement of ReentrantMutex.
The code in io::stdio before this change misused the ReentrantMutexes,
by calling init() on them and moving them afterwards. Now that
ReentrantMutex requires Pin for init(), this mistake is no longer easy
to make.
2020-12-08 22:57:57 +01:00
Mara Bos
8fe90966e1 Add (internal-only) SyncOnceCell::get_or_init_pin. 2020-12-08 22:57:50 +01:00
Mara Bos
9dc7f13c39 Remove unnecessary import of crate::marker in std::sys_common::remutex.
It was used for marker::Send, but Send is already in scope.
2020-12-08 22:57:49 +01:00
Mara Bos
2bc5d44ca9 Fix outdated comment about not needing to flush stderr. 2020-12-08 22:57:49 +01:00
Chai T. Rex
f1b930d57c Improved documentation for HashMap/BTreeMap Entry's .or_insert_with_key method 2020-12-07 21:36:01 -05:00
Eric Arellano
a3174de9ff Fix net.rs - rsplitn() returns a reverse iterator 2020-12-07 18:47:10 -07:00
Eric Arellano
d2de69da2e Dogfood 'str_split_once()` in the std lib 2020-12-07 14:24:05 -07:00
Jethro Beekman
9703bb8192 Fix SGX CI, take 3
Broken in #79038
2020-12-07 15:22:34 +01:00