Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 1099 insertions, 0 deletions

diff --git a/vendor/rustix/src/path/arg.rs b/vendor/rustix/src/path/arg.rs
new file mode 100644
index 0000000..f71125d
--- /dev/null
+++ b/vendor/rustix/src/path/arg.rs
@@ -0,0 +1,1099 @@
+//! Convenient and efficient string argument passing.
+//!
+//! This module defines the `Arg` trait and implements it for several common
+//! string types. This allows users to pass any of these string types directly
+//! to rustix APIs with string arguments, and it allows rustix to implement
+//! NUL-termination without the need for copying where possible.
+
+use crate::ffi::CStr;
+use crate::io;
+#[cfg(feature = "itoa")]
+use crate::path::DecInt;
+use crate::path::SMALL_PATH_BUFFER_SIZE;
+#[cfg(all(feature = "alloc", feature = "itoa"))]
+use alloc::borrow::ToOwned;
+use core::mem::MaybeUninit;
+use core::{ptr, slice, str};
+#[cfg(feature = "std")]
+use std::ffi::{OsStr, OsString};
+#[cfg(all(feature = "std", target_os = "hermit"))]
+use std::os::hermit::ext::ffi::{OsStrExt, OsStringExt};
+#[cfg(all(feature = "std", unix))]
+use std::os::unix::ffi::{OsStrExt, OsStringExt};
+#[cfg(all(feature = "std", target_os = "vxworks"))]
+use std::os::vxworks::ext::ffi::{OsStrExt, OsStringExt};
+#[cfg(all(feature = "std", target_os = "wasi"))]
+use std::os::wasi::ffi::{OsStrExt, OsStringExt};
+#[cfg(feature = "std")]
+use std::path::{Component, Components, Iter, Path, PathBuf};
+#[cfg(feature = "alloc")]
+use {crate::ffi::CString, alloc::borrow::Cow};
+#[cfg(feature = "alloc")]
+use {alloc::string::String, alloc::vec::Vec};
+
+/// A trait for passing path arguments.
+///
+/// This is similar to [`AsRef`]`<`[`Path`]`>`, but is implemented for more
+/// kinds of strings and can convert into more kinds of strings.
+///
+/// # Examples
+///
+/// ```
+/// # #[cfg(any(feature = "fs", feature = "net"))]
+/// use rustix::ffi::CStr;
+/// use rustix::io;
+/// # #[cfg(any(feature = "fs", feature = "net"))]
+/// use rustix::path::Arg;
+///
+/// # #[cfg(any(feature = "fs", feature = "net"))]
+/// pub fn touch<P: Arg>(path: P) -> io::Result<()> {
+///     let path = path.into_c_str()?;
+///     _touch(&path)
+/// }
+///
+/// # #[cfg(any(feature = "fs", feature = "net"))]
+/// fn _touch(path: &CStr) -> io::Result<()> {
+///     // implementation goes here
+///     Ok(())
+/// }
+/// ```
+///
+/// Users can then call `touch("foo")`, `touch(cstr!("foo"))`,
+/// `touch(Path::new("foo"))`, or many other things.
+///
+/// [`AsRef`]: std::convert::AsRef
+pub trait Arg {
+    /// Returns a view of this string as a string slice.
+    fn as_str(&self) -> io::Result<&str>;
+
+    /// Returns a potentially-lossy rendering of this string as a
+    /// `Cow<'_, str>`.
+    #[cfg(feature = "alloc")]
+    fn to_string_lossy(&self) -> Cow<'_, str>;
+
+    /// Returns a view of this string as a maybe-owned [`CStr`].
+    #[cfg(feature = "alloc")]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>>;
+
+    /// Consumes `self` and returns a view of this string as a maybe-owned
+    /// [`CStr`].
+    #[cfg(feature = "alloc")]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b;
+
+    /// Runs a closure with `self` passed in as a `&CStr`.
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>;
+}
+
+impl Arg for &str {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        Ok(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(*self).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Arg for &String {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        Ok(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(String::as_str(self)).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        self.as_str().into_c_str()
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Arg for String {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        Ok(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_str()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(&CString::new(self).map_err(|_cstr_err| io::Errno::INVAL)?)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Arg for &OsStr {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        OsStr::to_string_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Arg for &OsString {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        OsString::as_os_str(self).to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_os_str().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(OsString::as_os_str(self).as_bytes())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        self.as_os_str().into_c_str()
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Arg for OsString {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.as_os_str().to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_os_str().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.into_vec()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(&CString::new(self.into_vec()).map_err(|_cstr_err| io::Errno::INVAL)?)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Arg for &Path {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.as_os_str().to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Path::to_string_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_os_str().as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.as_os_str().as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_os_str().as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Arg for &PathBuf {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        PathBuf::as_path(self)
+            .as_os_str()
+            .to_str()
+            .ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_path().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(PathBuf::as_path(self).as_os_str().as_bytes())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        self.as_path().into_c_str()
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_os_str().as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+impl Arg for PathBuf {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.as_os_str().to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_os_str().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_os_str().as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.into_os_string().into_vec()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(
+            &CString::new(self.into_os_string().into_vec())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        )
+    }
+}
+
+impl Arg for &CStr {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.to_str().map_err(|_utf8_err| io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        CStr::to_string_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Borrowed(self))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Borrowed(self))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(self)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Arg for &CString {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        unimplemented!()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        unimplemented!()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Borrowed(self))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Borrowed(self))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(self)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Arg for CString {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.to_str().map_err(|_utf8_err| io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        CStr::to_string_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Borrowed(self))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(self))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(&self)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<'a> Arg for Cow<'a, str> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        Ok(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_ref()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            match self {
+                Cow::Owned(s) => CString::new(s),
+                Cow::Borrowed(s) => CString::new(s),
+            }
+            .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+#[cfg(feature = "alloc")]
+impl<'a> Arg for Cow<'a, OsStr> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        (**self).to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        (**self).to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            match self {
+                Cow::Owned(os) => CString::new(os.into_vec()),
+                Cow::Borrowed(os) => CString::new(os.as_bytes()),
+            }
+            .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<'a> Arg for Cow<'a, CStr> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.to_str().map_err(|_utf8_err| io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        let borrow: &CStr = core::borrow::Borrow::borrow(self);
+        borrow.to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Borrowed(self))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(self)
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(&self)
+    }
+}
+
+#[cfg(feature = "std")]
+impl<'a> Arg for Component<'a> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.as_os_str().to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_os_str().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_os_str().as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.as_os_str().as_bytes()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_os_str().as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+impl<'a> Arg for Components<'a> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.as_path().to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_path().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_path().as_os_str().as_bytes())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.as_path().as_os_str().as_bytes())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_path().as_os_str().as_bytes(), f)
+    }
+}
+
+#[cfg(feature = "std")]
+impl<'a> Arg for Iter<'a> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        self.as_path().to_str().ok_or(io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_path().to_string_lossy()
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_path().as_os_str().as_bytes())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.as_path().as_os_str().as_bytes())
+                .map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self.as_path().as_os_str().as_bytes(), f)
+    }
+}
+
+impl Arg for &[u8] {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        str::from_utf8(self).map_err(|_utf8_err| io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(*self).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self, f)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Arg for &Vec<u8> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        str::from_utf8(self).map_err(|_utf8_err| io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_slice()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self.as_slice()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        with_c_str(self, f)
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl Arg for Vec<u8> {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        str::from_utf8(self).map_err(|_utf8_err| io::Errno::INVAL)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(self)
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Owned(
+            CString::new(self.as_slice()).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(
+            CString::new(self).map_err(|_cstr_err| io::Errno::INVAL)?,
+        ))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(&CString::new(self).map_err(|_cstr_err| io::Errno::INVAL)?)
+    }
+}
+
+#[cfg(feature = "itoa")]
+impl Arg for DecInt {
+    #[inline]
+    fn as_str(&self) -> io::Result<&str> {
+        Ok(self.as_str())
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self.as_str())
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn as_cow_c_str(&self) -> io::Result<Cow<'_, CStr>> {
+        Ok(Cow::Borrowed(self.as_c_str()))
+    }
+
+    #[cfg(feature = "alloc")]
+    #[inline]
+    fn into_c_str<'b>(self) -> io::Result<Cow<'b, CStr>>
+    where
+        Self: 'b,
+    {
+        Ok(Cow::Owned(self.as_c_str().to_owned()))
+    }
+
+    #[inline]
+    fn into_with_c_str<T, F>(self, f: F) -> io::Result<T>
+    where
+        Self: Sized,
+        F: FnOnce(&CStr) -> io::Result<T>,
+    {
+        f(self.as_c_str())
+    }
+}
+
+/// Runs a closure with `bytes` passed in as a `&CStr`.
+#[allow(unsafe_code, clippy::int_plus_one)]
+#[inline]
+fn with_c_str<T, F>(bytes: &[u8], f: F) -> io::Result<T>
+where
+    F: FnOnce(&CStr) -> io::Result<T>,
+{
+    // Most paths are less than `SMALL_PATH_BUFFER_SIZE` long. The rest can go
+    // through the dynamic allocation path. If you're opening many files in a
+    // directory with a long path, consider opening the directory and using
+    // `openat` to open the files under it, which will avoid this, and is often
+    // faster in the OS as well.
+
+    // Test with >= so that we have room for the trailing NUL.
+    if bytes.len() >= SMALL_PATH_BUFFER_SIZE {
+        return with_c_str_slow_path(bytes, f);
+    }
+
+    // Taken from
+    // <https://github.com/rust-lang/rust/blob/a00f8ba7fcac1b27341679c51bf5a3271fa82df3/library/std/src/sys/common/small_c_string.rs>
+    let mut buf = MaybeUninit::<[u8; SMALL_PATH_BUFFER_SIZE]>::uninit();
+    let buf_ptr = buf.as_mut_ptr().cast::<u8>();
+
+    // This helps test our safety condition below.
+    debug_assert!(bytes.len() + 1 <= SMALL_PATH_BUFFER_SIZE);
+
+    // SAFETY: `bytes.len() < SMALL_PATH_BUFFER_SIZE` which means we have space
+    // for `bytes.len() + 1` u8s:
+    unsafe {
+        ptr::copy_nonoverlapping(bytes.as_ptr(), buf_ptr, bytes.len());
+        buf_ptr.add(bytes.len()).write(0);
+    }
+
+    // SAFETY: We just wrote the bytes above and they will remain valid for the
+    // duration of `f` b/c buf doesn't get dropped until the end of the
+    // function.
+    match CStr::from_bytes_with_nul(unsafe { slice::from_raw_parts(buf_ptr, bytes.len() + 1) }) {
+        Ok(s) => f(s),
+        Err(_) => Err(io::Errno::INVAL),
+    }
+}
+
+/// The slow path which handles any length. In theory OS's only support up to
+/// `PATH_MAX`, but we let the OS enforce that.
+#[allow(unsafe_code, clippy::int_plus_one)]
+#[cold]
+fn with_c_str_slow_path<T, F>(bytes: &[u8], f: F) -> io::Result<T>
+where
+    F: FnOnce(&CStr) -> io::Result<T>,
+{
+    #[cfg(feature = "alloc")]
+    {
+        f(&CString::new(bytes).map_err(|_cstr_err| io::Errno::INVAL)?)
+    }
+
+    #[cfg(not(feature = "alloc"))]
+    {
+        #[cfg(all(libc, not(target_os = "wasi")))]
+        const LARGE_PATH_BUFFER_SIZE: usize = libc::PATH_MAX as usize;
+        #[cfg(linux_raw)]
+        const LARGE_PATH_BUFFER_SIZE: usize = linux_raw_sys::general::PATH_MAX as usize;
+        #[cfg(target_os = "wasi")]
+        const LARGE_PATH_BUFFER_SIZE: usize = 4096 as usize; // TODO: upstream this
+
+        // Taken from
+        // <https://github.com/rust-lang/rust/blob/a00f8ba7fcac1b27341679c51bf5a3271fa82df3/library/std/src/sys/common/small_c_string.rs>
+        let mut buf = MaybeUninit::<[u8; LARGE_PATH_BUFFER_SIZE]>::uninit();
+        let buf_ptr = buf.as_mut_ptr().cast::<u8>();
+
+        // This helps test our safety condition below.
+        if bytes.len() + 1 > LARGE_PATH_BUFFER_SIZE {
+            return Err(io::Errno::NAMETOOLONG);
+        }
+
+        // SAFETY: `bytes.len() < LARGE_PATH_BUFFER_SIZE` which means we have
+        // space for `bytes.len() + 1` u8s:
+        unsafe {
+            ptr::copy_nonoverlapping(bytes.as_ptr(), buf_ptr, bytes.len());
+            buf_ptr.add(bytes.len()).write(0);
+        }
+
+        // SAFETY: We just wrote the bytes above and they will remain valid for
+        // the duration of `f` b/c buf doesn't get dropped until the end of the
+        // function.
+        match CStr::from_bytes_with_nul(unsafe { slice::from_raw_parts(buf_ptr, bytes.len() + 1) })
+        {
+            Ok(s) => f(s),
+            Err(_) => Err(io::Errno::INVAL),
+        }
+    }
+}