Skip to content

deny(unsafe_op_in_unsafe_fn) in libstd/path.rs #73956

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 1 commit into from
Closed

deny(unsafe_op_in_unsafe_fn) in libstd/path.rs #73956

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 19 additions & 20 deletions src/libstd/path.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,7 @@
//! [`OsStr`]: ../../std/ffi/struct.OsStr.html

#![stable(feature = "rust1", since = "1.0.0")]
#![deny(unsafe_op_in_unsafe_fn)]

use crate::borrow::{Borrow, Cow};
use crate::cmp;
Expand Down Expand Up @@ -301,7 +302,8 @@ fn os_str_as_u8_slice(s: &OsStr) -> &[u8] {
unsafe { &*(s as *const OsStr as *const [u8]) }
}
unsafe fn u8_slice_as_os_str(s: &[u8]) -> &OsStr {
&*(s as *const [u8] as *const OsStr)
// SAFETY: see the comment of `os_str_as_u8_slice`
unsafe { &*(s as *const [u8] as *const OsStr) }
}

// Detect scheme on Redox
Expand All @@ -321,24 +323,21 @@ fn has_physical_root(s: &[u8], prefix: Option<Prefix<'_>>) -> bool {

// basic workhorse for splitting stem and extension
fn split_file_at_dot(file: &OsStr) -> (Option<&OsStr>, Option<&OsStr>) {
unsafe {
if os_str_as_u8_slice(file) == b".." {
return (Some(file), None);
}

// The unsafety here stems from converting between &OsStr and &[u8]
// and back. This is safe to do because (1) we only look at ASCII
// contents of the encoding and (2) new &OsStr values are produced
// only from ASCII-bounded slices of existing &OsStr values.

let mut iter = os_str_as_u8_slice(file).rsplitn(2, |b| *b == b'.');
let after = iter.next();
let before = iter.next();
if before == Some(b"") {
(Some(file), None)
} else {
(before.map(|s| u8_slice_as_os_str(s)), after.map(|s| u8_slice_as_os_str(s)))
}
if os_str_as_u8_slice(file) == b".." {
return (Some(file), None);
}

// The unsafety here stems from converting between &OsStr and &[u8]
// and back. This is safe to do because (1) we only look at ASCII
// contents of the encoding and (2) new &OsStr values are produced
// only from ASCII-bounded slices of existing &OsStr values.
let mut iter = os_str_as_u8_slice(file).rsplitn(2, |b| *b == b'.');
let after = iter.next();
let before = iter.next();
if before == Some(b"") {
(Some(file), None)
} else {
unsafe { (before.map(|s| u8_slice_as_os_str(s)), after.map(|s| u8_slice_as_os_str(s))) }
}
}

Expand Down Expand Up @@ -1755,7 +1754,7 @@ impl Path {
// The following (private!) function allows construction of a path from a u8
// slice, which is only safe when it is known to follow the OsStr encoding.
unsafe fn from_u8_slice(s: &[u8]) -> &Path {
Path::new(u8_slice_as_os_str(s))
unsafe { Path::new(u8_slice_as_os_str(s)) }
}
// The following (private!) function reveals the byte encoding used for OsStr.
fn as_u8_slice(&self) -> &[u8] {
Expand Down