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use std::borrow::Cow;
use std::ffi::OsStr;
use std::path::Path;
/// The final component of the path, if it is a normal file.
///
/// If the path terminates in ., .., or consists solely of a root of prefix,
/// file_name will return None.
#[cfg(unix)]
pub fn file_name<'a, P: AsRef<Path> + ?Sized>(
path: &'a P,
) -> Option<&'a OsStr> {
use std::os::unix::ffi::OsStrExt;
use memchr::memrchr;
let path = path.as_ref().as_os_str().as_bytes();
if path.is_empty() {
return None;
} else if path.len() == 1 && path[0] == b'.' {
return None;
} else if path.last() == Some(&b'.') {
return None;
} else if path.len() >= 2 && &path[path.len() - 2..] == &b".."[..] {
return None;
}
let last_slash = memrchr(b'/', path).map(|i| i + 1).unwrap_or(0);
Some(OsStr::from_bytes(&path[last_slash..]))
}
/// The final component of the path, if it is a normal file.
///
/// If the path terminates in ., .., or consists solely of a root of prefix,
/// file_name will return None.
#[cfg(not(unix))]
pub fn file_name<'a, P: AsRef<Path> + ?Sized>(
path: &'a P,
) -> Option<&'a OsStr> {
path.as_ref().file_name()
}
/// Return a file extension given a path's file name.
///
/// Note that this does NOT match the semantics of std::path::Path::extension.
/// Namely, the extension includes the `.` and matching is otherwise more
/// liberal. Specifically, the extenion is:
///
/// * None, if the file name given is empty;
/// * None, if there is no embedded `.`;
/// * Otherwise, the portion of the file name starting with the final `.`.
///
/// e.g., A file name of `.rs` has an extension `.rs`.
///
/// N.B. This is done to make certain glob match optimizations easier. Namely,
/// a pattern like `*.rs` is obviously trying to match files with a `rs`
/// extension, but it also matches files like `.rs`, which doesn't have an
/// extension according to std::path::Path::extension.
pub fn file_name_ext(name: &OsStr) -> Option<&OsStr> {
// Yes, these functions are awful, and yes, we are completely violating
// the abstraction barrier of std::ffi. The barrier we're violating is
// that an OsStr's encoding is *ASCII compatible*. While this is obviously
// true on Unix systems, it's also true on Windows because an OsStr uses
// WTF-8 internally: https://simonsapin.github.io/wtf-8/
//
// We should consider doing the same for the other path utility functions.
// Right now, we don't break any barriers, but Windows users are paying
// for it.
//
// Got any better ideas that don't cost anything? Hit me up. ---AG
unsafe fn os_str_as_u8_slice(s: &OsStr) -> &[u8] {
::std::mem::transmute(s)
}
unsafe fn u8_slice_as_os_str(s: &[u8]) -> &OsStr {
::std::mem::transmute(s)
}
if name.is_empty() {
return None;
}
let name = unsafe { os_str_as_u8_slice(name) };
for (i, &b) in name.iter().enumerate().rev() {
if b == b'.' {
return Some(unsafe { u8_slice_as_os_str(&name[i..]) });
}
}
None
}
/// Return raw bytes of a path, transcoded to UTF-8 if necessary.
pub fn path_bytes(path: &Path) -> Cow<[u8]> {
os_str_bytes(path.as_os_str())
}
/// Return the raw bytes of the given OS string, possibly transcoded to UTF-8.
#[cfg(unix)]
pub fn os_str_bytes(s: &OsStr) -> Cow<[u8]> {
use std::os::unix::ffi::OsStrExt;
Cow::Borrowed(s.as_bytes())
}
/// Return the raw bytes of the given OS string, possibly transcoded to UTF-8.
#[cfg(not(unix))]
pub fn os_str_bytes(s: &OsStr) -> Cow<[u8]> {
// TODO(burntsushi): On Windows, OS strings are WTF-8, which is a superset
// of UTF-8, so even if we could get at the raw bytes, they wouldn't
// be useful. We *must* convert to UTF-8 before doing path matching.
// Unfortunate, but necessary.
match s.to_string_lossy() {
Cow::Owned(s) => Cow::Owned(s.into_bytes()),
Cow::Borrowed(s) => Cow::Borrowed(s.as_bytes()),
}
}
/// Normalizes a path to use `/` as a separator everywhere, even on platforms
/// that recognize other characters as separators.
#[cfg(unix)]
pub fn normalize_path(path: Cow<[u8]>) -> Cow<[u8]> {
// UNIX only uses /, so we're good.
path
}
/// Normalizes a path to use `/` as a separator everywhere, even on platforms
/// that recognize other characters as separators.
#[cfg(not(unix))]
pub fn normalize_path(mut path: Cow<[u8]>) -> Cow<[u8]> {
use std::path::is_separator;
for i in 0..path.len() {
if path[i] == b'/' || !is_separator(path[i] as char) {
continue;
}
path.to_mut()[i] = b'/';
}
path
}
#[cfg(test)]
mod tests {
use std::borrow::Cow;
use std::ffi::OsStr;
use super::{file_name_ext, normalize_path};
macro_rules! ext {
($name:ident, $file_name:expr, $ext:expr) => {
#[test]
fn $name() {
let got = file_name_ext(OsStr::new($file_name));
assert_eq!($ext.map(OsStr::new), got);
}
};
}
ext!(ext1, "foo.rs", Some(".rs"));
ext!(ext2, ".rs", Some(".rs"));
ext!(ext3, "..rs", Some(".rs"));
ext!(ext4, "", None::<&str>);
ext!(ext5, "foo", None::<&str>);
macro_rules! normalize {
($name:ident, $path:expr, $expected:expr) => {
#[test]
fn $name() {
let got = normalize_path(Cow::Owned($path.to_vec()));
assert_eq!($expected.to_vec(), got.into_owned());
}
};
}
normalize!(normal1, b"foo", b"foo");
normalize!(normal2, b"foo/bar", b"foo/bar");
#[cfg(unix)]
normalize!(normal3, b"foo\\bar", b"foo\\bar");
#[cfg(not(unix))]
normalize!(normal3, b"foo\\bar", b"foo/bar");
#[cfg(unix)]
normalize!(normal4, b"foo\\bar/baz", b"foo\\bar/baz");
#[cfg(not(unix))]
normalize!(normal4, b"foo\\bar/baz", b"foo/bar/baz");
}
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