Replace generic thread parker with explicit no-op parker
With #98391 merged, all platforms supporting threads now have their own parking implementations. Therefore, the generic implementation can be removed. On the remaining platforms (really just WASM without atomics), parking is not supported, so calls to `thread::park` now return instantly, which is [allowed by their API](https://doc.rust-lang.org/nightly/std/thread/fn.park.html). This is a change in behaviour, as spurious wakeups do not currently occur since all platforms guard against them. It is invalid to depend on this, but I'm still going to tag this as libs-api for confirmation.
````@rustbot```` label +T-libs +T-libs-api +A-atomic
r? rust-lang/libs
Implement read_buf for TcpStream, Stdin, StdinLock, ChildStdout,
ChildStderr (and internally for AnonPipe, Handle, Socket), so
that it skips buffer initialization.
The other provided methods like read_to_string and read_to_end are
implemented in terms of read_buf and so benefit from the optimization
as well.
This commit also implements read_vectored and is_read_vectored where
applicable.
Use `__wasilibc_get_environ()` to read the environment variable list
from wasi-libc instead of using `environ`. `environ` is a global
variable which effectively requires wasi-libc to initialize the
environment variables eagerly, and `__wasilibc_get_environ()` is
specifically designed to be an alternative that lets wasi-libc
intiailize its environment variables lazily.
This should have the side effect of fixing at least some of the cases
of #107635.
The UNIX and WASI implementations use `isatty`. The Windows
implementation uses the same logic the `atty` crate uses, including the
hack needed to detect msys terminals.
Implement this trait for `File` and for `Stdin`/`Stdout`/`Stderr` and
their locked counterparts on all platforms. On UNIX and WASI, implement
it for `BorrowedFd`/`OwnedFd`. On Windows, implement it for
`BorrowedHandle`/`OwnedHandle`.
Based on https://github.com/rust-lang/rust/pull/91121
Co-authored-by: Matt Wilkinson <mattwilki17@gmail.com>
impl AsFd and AsRawFd for io::{Stdin, Stdout, Stderr}, not the sys versions
https://github.com/rust-lang/rust/pull/100892 implemented AsFd for the
sys versions, rather than for the public types. Change the
implementations to apply to the public types.
Copying the approach of the Unix target, this change uses the standard
`RwLock` to protect against concurrent access of libc's environment.
This locking is only enabled when WebAssembly's `atomics` feature is
also enabled.
The issue #102157 demonstrates how currently the `-Z build-std` option
will fail when re-compiling the standard library with `RUSTFLAGS` like
`RUSTFLAGS="-C target-feature=+atomics,+bulk-memory -C
link-args=--shared-memory"`. This change attempts to resolve those build
issues by depending on the the WebAssembly `futex` module and providing
an implementation for `env_lock`. Fixes#102157.
Reduce CString allocations in std as much as possible
Currently, every operation involving paths in `fs` allocates memory to hold the path before sending it through the syscall. This PR instead uses a stack allocation (chosen size is somewhat arbitrary) when the path is short before falling back to heap allocations for long paths.
Benchmarks show that the stack allocation is ~2x faster for short paths:
```
test sys::unix::fd::tests::bench_heap_path_alloc ... bench: 34 ns/iter (+/- 2)
test sys::unix::fd::tests::bench_stack_path_alloc ... bench: 15 ns/iter (+/- 1)
```
For long paths, I couldn't find any measurable difference.
---
I'd be surprised if I was the first to think of this, so I didn't fully flush out the PR. If this change is desirable, I'll make use of `run_with_cstr` across all platforms in every fs method (currently just unix open for testing). I also added an `impl From<FromBytesWithNulError>` which is presumably a no-no (or at least needs to be done in another PR).
---
Also see https://github.com/nix-rust/nix/pull/1655 with a bunch of discussion where I'm doing something similar.
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.
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.
Support setting file accessed/modified timestamps
Add `struct FileTimes` to contain the relevant file timestamps, since
most platforms require setting all of them at once. (This also allows
for future platform-specific extensions such as setting creation time.)
Add `File::set_file_time` to set the timestamps for a `File`.
Implement the `sys` backends for UNIX, macOS (which needs to fall back
to `futimes` before macOS 10.13 because it lacks `futimens`), Windows,
and WASI.
Add `struct FileTimes` to contain the relevant file timestamps, since
most platforms require setting all of them at once. (This also allows
for future platform-specific extensions such as setting creation time.)
Add `File::set_file_time` to set the timestamps for a `File`.
Implement the `sys` backends for UNIX, macOS (which needs to fall back
to `futimes` before macOS 10.13 because it lacks `futimens`), Windows,
and WASI.
This removes all mutex/atomics based workarounds for non-monotonic clocks and makes the previously panicking methods saturating instead.
Effectively this moves the monotonization from `Instant` construction to the comparisons.
This has some observable effects, especially on platforms without monotonic clocks:
* Incorrectly ordered Instant comparisons no longer panic. This may hide some programming errors until someone actually looks at the resulting `Duration`
* `checked_duration_since` will now return `None` in more cases. Previously it only happened when one compared instants obtained in the wrong order or
manually created ones. Now it also does on backslides.
The upside is reduced complexity and lower overhead of `Instant::now`.
With the addition of `sock_accept()` to snapshot1, simple networking via
a passed `TcpListener` is possible. This patch implements the basics to
make a simple server work.
Signed-off-by: Harald Hoyer <harald@profian.com>
