Basic cross-platform file accessibility checks for Rust.
```rust pub trait PathExt { fn access(&self, mode: AccessMode) -> std::io::Result<()>; fn readable(&self) -> bool; fn writable(&self) -> bool; fn executable(&self) -> bool; }
impl PathExt for std::path::Path; ```
faccess provides an extension trait for std::path::Path which adds an
access method for checking the accessibility of a path for the given access
permissions — a bitwise-inclusive OR of one or more AccessMode flags
(EXISTS, READ, WRITE, EXECUTE).
It also provides convenience methods readable, writable, and executable
if only a single permission needs to be checked in a simple boolean fashion.
```rust use std::path::Path; use faccess::{AccessMode, PathExt};
let path = Path::new("/bin/ls");
assert!(path.access(AccessMode::READ | AccessMode::EXECUTE).is_ok()); assert!(path.readable()); assert!(!path.writable()); assert!(path.executable()); ```
On Unix platforms, access directly maps to [faccessat(2)], with the
AT_EACCESS flag used where available to test against the effective user and
group ID's.
On Windows, a complex custom implementation is used to approximate these
semantics in a best-effort fashion, using a mixture of file extension checks,
simply attempting to open a file, [GetNamedSecurityInfoW], and [AccessCheck],
depending on the permissions being checked. This is similar to implementations
found in other languages.
On other platforms it simply proxies to exists() and readonly() as appropriate.
There is a history of time-of-check to time-of-use ([TOCTOU]) bugs with this class of function, particularly with set-user-ID programs relying on them to validate effective user/group permissions prior to accessing files on behalf of other users. They should not be relied upon in a security context.