sgx_tstd/src/ffi/os_str.rs - incubator-teaclave-sgx-sdk - Git at Google

 // Licensed to the Apache Software Foundation (ASF) under one
 // or more contributor license agreements.  See the NOTICE file
 // distributed with this work for additional information
 // regarding copyright ownership.  The ASF licenses this file
 // to you under the Apache License, Version 2.0 (the
 // "License"); you may not use this file except in compliance
 // with the License.  You may obtain a copy of the License at
 //
 //   http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing,
 // software distributed under the License is distributed on an
 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 // KIND, either express or implied.  See the License for the
 // specific language governing permissions and limitations
 // under the License..

 use crate::sys::os_str::{Buf, Slice};
 use crate::sys_common::{AsInner, FromInner, IntoInner};
 use core::ops;
 use core::cmp;
 use core::hash::{Hash, Hasher};
 use core::fmt;
 use alloc_crate::borrow::{Borrow, Cow, ToOwned};
 use alloc_crate::string::String;
 use alloc_crate::boxed::Box;
 use alloc_crate::rc::Rc;
 use alloc_crate::sync::Arc;


 /// A type that can represent owned, mutable platform-native strings, but is
 /// cheaply inter-convertible with Rust strings.
 ///
 #[derive(Clone)]
 pub struct OsString {
     inner: Buf,
 }

 /// Borrowed reference to an OS string (see [`OsString`]).
 ///
 /// This type represents a borrowed reference to a string in the operating system's preferred
 /// representation.
 ///
 /// `&OsStr` is to [`OsString`] as [`&str`] is to [`String`]: the former in each pair are borrowed
 /// references; the latter are owned strings.
 ///
 /// See the [module's toplevel documentation about conversions][conversions] for a discussion on
 /// the traits which `OsStr` implements for [conversions] from/to native representations.
 ///
 /// [`OsString`]: struct.OsString.html
 /// [`&str`]: ../primitive.str.html
 /// [`String`]: ../string/struct.String.html
 /// [conversions]: index.html#conversions
 pub struct OsStr {
     inner: Slice,
 }

 impl OsString {
     /// Constructs a new empty `OsString`.
     ///
     pub fn new() -> OsString {
         OsString { inner: Buf::from_string(String::new()) }
     }

     /// Converts to an [`OsStr`] slice.
     ///
     /// [`OsStr`]: struct.OsStr.html
     ///
     pub fn as_os_str(&self) -> &OsStr {
         self
     }

     /// Converts the `OsString` into a [`String`] if it contains valid Unicode data.
     ///
     /// On failure, ownership of the original `OsString` is returned.
     ///
     /// [`String`]: ../../std/string/struct.String.html
     ///
     pub fn into_string(self) -> Result<String, OsString> {
         self.inner.into_string().map_err(|buf| OsString { inner: buf })
     }

     /// Extends the string with the given [`&OsStr`] slice.
     ///
     /// [`&OsStr`]: struct.OsStr.html
     ///
     pub fn push<T: AsRef<OsStr>>(&mut self, s: T) {
         self.inner.push_slice(&s.as_ref().inner)
     }

     /// Creates a new `OsString` with the given capacity.
     ///
     /// The string will be able to hold exactly `capacity` length units of other
     /// OS strings without reallocating. If `capacity` is 0, the string will not
     /// allocate.
     ///
     /// See main `OsString` documentation information about encoding.
     ///
     pub fn with_capacity(capacity: usize) -> OsString {
         OsString { inner: Buf::with_capacity(capacity) }
     }

     /// Truncates the `OsString` to zero length.
     ///
     pub fn clear(&mut self) {
         self.inner.clear()
     }

     /// Returns the capacity this `OsString` can hold without reallocating.
     ///
     /// See `OsString` introduction for information about encoding.
     ///
     pub fn capacity(&self) -> usize {
         self.inner.capacity()
     }

     /// Reserves capacity for at least `additional` more capacity to be inserted
     /// in the given `OsString`.
     ///
     /// The collection may reserve more space to avoid frequent reallocations.
     ///
     pub fn reserve(&mut self, additional: usize) {
         self.inner.reserve(additional)
     }

     /// Reserves the minimum capacity for exactly `additional` more capacity to
     /// be inserted in the given `OsString`. Does nothing if the capacity is
     /// already sufficient.
     ///
     /// Note that the allocator may give the collection more space than it
     /// requests. Therefore, capacity can not be relied upon to be precisely
     /// minimal. Prefer reserve if future insertions are expected.
     ///
     pub fn reserve_exact(&mut self, additional: usize) {
         self.inner.reserve_exact(additional)
     }

     /// Shrinks the capacity of the `OsString` to match its length.
     ///
     pub fn shrink_to_fit(&mut self) {
         self.inner.shrink_to_fit()
     }

     /// Shrinks the capacity of the `OsString` with a lower bound.
     ///
     /// The capacity will remain at least as large as both the length
     /// and the supplied value.
     ///
     /// Panics if the current capacity is smaller than the supplied
     /// minimum capacity.
     ///
     #[inline]
     pub fn shrink_to(&mut self, min_capacity: usize) {
         self.inner.shrink_to(min_capacity)
     }

     /// Converts this `OsString` into a boxed [`OsStr`].
     ///
     /// [`OsStr`]: struct.OsStr.html
     ///
     pub fn into_boxed_os_str(self) -> Box<OsStr> {
         let rw = Box::into_raw(self.inner.into_box()) as *mut OsStr;
         unsafe { Box::from_raw(rw) }
     }
 }

 impl From<String> for OsString {
     /// Converts a [`String`] into a [`OsString`].
     ///
     /// The conversion copies the data, and includes an allocation on the heap.
     ///
     /// [`OsString`]: ../../std/ffi/struct.OsString.html
     fn from(s: String) -> OsString {
         OsString { inner: Buf::from_string(s) }
     }
 }

 impl<T: ?Sized + AsRef<OsStr>> From<&T> for OsString {
     fn from(s: &T) -> OsString {
         s.as_ref().to_os_string()
     }
 }

 impl ops::Index<ops::RangeFull> for OsString {
     type Output = OsStr;

     #[inline]
     fn index(&self, _index: ops::RangeFull) -> &OsStr {
         OsStr::from_inner(self.inner.as_slice())
     }
 }

 impl ops::IndexMut<ops::RangeFull> for OsString {
     #[inline]
     fn index_mut(&mut self, _index: ops::RangeFull) -> &mut OsStr {
         OsStr::from_inner_mut(self.inner.as_mut_slice())
     }
 }

 impl ops::Deref for OsString {
     type Target = OsStr;

     #[inline]
     fn deref(&self) -> &OsStr {
         &self[..]
     }
 }

 impl ops::DerefMut for OsString {
     #[inline]
     fn deref_mut(&mut self) -> &mut OsStr {
         &mut self[..]
     }
 }

 impl Default for OsString {
     /// Constructs an empty `OsString`.
     #[inline]
     fn default() -> OsString {
         OsString::new()
     }
 }

 impl fmt::Debug for OsString {
     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&**self, formatter)
     }
 }

 impl PartialEq for OsString {
     fn eq(&self, other: &OsString) -> bool {
         &**self == &**other
     }
 }

 impl PartialEq<str> for OsString {
     fn eq(&self, other: &str) -> bool {
         &**self == other
     }
 }

 impl PartialEq<OsString> for str {
     fn eq(&self, other: &OsString) -> bool {
         &**other == self
     }
 }

 impl PartialEq<&str> for OsString {
     fn eq(&self, other: &&str) -> bool {
         **self == **other
     }
 }

 impl<'a> PartialEq<OsString> for &'a str {
     fn eq(&self, other: &OsString) -> bool {
         **other == **self
     }
 }

 impl Eq for OsString {}

 impl PartialOrd for OsString {
     #[inline]
     fn partial_cmp(&self, other: &OsString) -> Option<cmp::Ordering> {
         (&**self).partial_cmp(&**other)
     }
     #[inline]
     fn lt(&self, other: &OsString) -> bool {
         &**self < &**other
     }
     #[inline]
     fn le(&self, other: &OsString) -> bool {
         &**self <= &**other
     }
     #[inline]
     fn gt(&self, other: &OsString) -> bool {
         &**self > &**other
     }
     #[inline]
     fn ge(&self, other: &OsString) -> bool {
         &**self >= &**other
     }
 }

 impl PartialOrd<str> for OsString {
     #[inline]
     fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
         (&**self).partial_cmp(other)
     }
 }

 impl Ord for OsString {
     #[inline]
     fn cmp(&self, other: &OsString) -> cmp::Ordering {
         (&**self).cmp(&**other)
     }
 }

 impl Hash for OsString {
     #[inline]
     fn hash<H: Hasher>(&self, state: &mut H) {
         (&**self).hash(state)
     }
 }

 impl OsStr {
     /// Coerces into an `OsStr` slice.
     ///
     pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &OsStr {
         s.as_ref()
     }

     #[inline]
     fn from_inner(inner: &Slice) -> &OsStr {
         // Safety: OsStr is just a wrapper of Slice,
         // therefore converting &Slice to &OsStr is safe.
         unsafe { &*(inner as *const Slice as *const OsStr) }
     }

     #[inline]
     fn from_inner_mut(inner: &mut Slice) -> &mut OsStr {
         // Safety: OsStr is just a wrapper of Slice,
         // therefore converting &mut Slice to &mut OsStr is safe.
         // Any method that mutates OsStr must be careful not to
         // break platform-specific encoding, in particular Wtf8 on Windows.
         unsafe { &mut *(inner as *mut Slice as *mut OsStr) }
     }

     /// Yields a [`&str`] slice if the `OsStr` is valid Unicode.
     ///
     /// This conversion may entail doing a check for UTF-8 validity.
     ///
     /// [`&str`]: ../../std/primitive.str.html
     ///
     pub fn to_str(&self) -> Option<&str> {
         self.inner.to_str()
     }

     /// Converts an `OsStr` to a [`Cow`]`<`[`str`]`>`.
     ///
     /// Any non-Unicode sequences are replaced with
     /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD].
     ///
     /// [`Cow`]: ../../std/borrow/enum.Cow.html
     /// [`str`]: ../../std/primitive.str.html
     /// [U+FFFD]: ../../std/char/constant.REPLACEMENT_CHARACTER.html
     ///
     pub fn to_string_lossy(&self) -> Cow<'_, str> {
         self.inner.to_string_lossy()
     }

     /// Copies the slice into an owned [`OsString`].
     ///
     /// [`OsString`]: struct.OsString.html
     ///
     pub fn to_os_string(&self) -> OsString {
         OsString { inner: self.inner.to_owned() }
     }

     /// Checks whether the `OsStr` is empty.
     ///
     pub fn is_empty(&self) -> bool {
         self.inner.inner.is_empty()
     }

     /// Returns the length of this `OsStr`.
     ///
     /// Note that this does **not** return the number of bytes in the string in
     /// OS string form.
     ///
     /// The length returned is that of the underlying storage used by `OsStr`.
     /// As discussed in the [`OsString`] introduction, [`OsString`] and `OsStr`
     /// store strings in a form best suited for cheap inter-conversion between
     /// native-platform and Rust string forms, which may differ significantly
     /// from both of them, including in storage size and encoding.
     ///
     /// This number is simply useful for passing to other methods, like
     /// [`OsString::with_capacity`] to avoid reallocations.
     ///
     /// [`OsString`]: struct.OsString.html
     /// [`OsString::with_capacity`]: struct.OsString.html#method.with_capacity
     ///
     pub fn len(&self) -> usize {
         self.inner.inner.len()
     }

     /// Converts a [`Box`]`<OsStr>` into an [`OsString`] without copying or allocating.
     ///
     /// [`Box`]: ../boxed/struct.Box.html
     /// [`OsString`]: struct.OsString.html
     pub fn into_os_string(self: Box<OsStr>) -> OsString {
         let boxed = unsafe { Box::from_raw(Box::into_raw(self) as *mut Slice) };
         OsString { inner: Buf::from_box(boxed) }
     }

     /// Gets the underlying byte representation.
     ///
     /// Note: it is *crucial* that this API is private, to avoid
     /// revealing the internal, platform-specific encodings.
     #[inline]
     fn bytes(&self) -> &[u8] {
         unsafe { &*(&self.inner as *const _ as *const [u8]) }
     }

     /// Converts this string to its ASCII lower case equivalent in-place.
     ///
     /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
     /// but non-ASCII letters are unchanged.
     ///
     /// To return a new lowercased value without modifying the existing one, use
     /// [`to_ascii_lowercase`].
     ///
     /// [`to_ascii_lowercase`]: #method.to_ascii_lowercase
     ///
     pub fn make_ascii_lowercase(&mut self) {
         self.inner.make_ascii_lowercase()
     }

     /// Converts this string to its ASCII upper case equivalent in-place.
     ///
     /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
     /// but non-ASCII letters are unchanged.
     ///
     /// To return a new uppercased value without modifying the existing one, use
     /// [`to_ascii_uppercase`].
     ///
     /// [`to_ascii_uppercase`]: #method.to_ascii_uppercase
     ///
     pub fn make_ascii_uppercase(&mut self) {
         self.inner.make_ascii_uppercase()
     }

     /// Returns a copy of this string where each character is mapped to its
     /// ASCII lower case equivalent.
     ///
     /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
     /// but non-ASCII letters are unchanged.
     ///
     /// To lowercase the value in-place, use [`make_ascii_lowercase`].
     ///
     /// [`make_ascii_lowercase`]: #method.make_ascii_lowercase
     ///
     pub fn to_ascii_lowercase(&self) -> OsString {
         OsString::from_inner(self.inner.to_ascii_lowercase())
     }

     /// Returns a copy of this string where each character is mapped to its
     /// ASCII upper case equivalent.
     ///
     /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
     /// but non-ASCII letters are unchanged.
     ///
     /// To uppercase the value in-place, use [`make_ascii_uppercase`].
     ///
     /// [`make_ascii_uppercase`]: #method.make_ascii_uppercase
     ///
     pub fn to_ascii_uppercase(&self) -> OsString {
         OsString::from_inner(self.inner.to_ascii_uppercase())
     }

     /// Checks if all characters in this string are within the ASCII range.
     ///
     pub fn is_ascii(&self) -> bool {
         self.inner.is_ascii()
     }

     /// Checks that two strings are an ASCII case-insensitive match.
     ///
     /// Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`,
     /// but without allocating and copying temporaries.
     ///
     pub fn eq_ignore_ascii_case<S: ?Sized + AsRef<OsStr>>(&self, other: &S) -> bool {
         self.inner.eq_ignore_ascii_case(&other.as_ref().inner)
     }
 }

 impl From<&OsStr> for Box<OsStr> {
     fn from(s: &OsStr) -> Box<OsStr> {
         let rw = Box::into_raw(s.inner.into_box()) as *mut OsStr;
         unsafe { Box::from_raw(rw) }
     }
 }

 impl From<Box<OsStr>> for OsString {
     /// Converts a [`Box`]`<`[`OsStr`]`>` into a `OsString` without copying or
     /// allocating.
     ///
     /// [`Box`]: ../boxed/struct.Box.html
     /// [`OsStr`]: ../ffi/struct.OsStr.html
     fn from(boxed: Box<OsStr>) -> OsString {
         boxed.into_os_string()
     }
 }

 impl From<OsString> for Box<OsStr> {
     /// Converts a [`OsString`] into a [`Box`]`<OsStr>` without copying or allocating.
     ///
     /// [`Box`]: ../boxed/struct.Box.html
     /// [`OsString`]: ../ffi/struct.OsString.html
     fn from(s: OsString) -> Box<OsStr> {
         s.into_boxed_os_str()
     }
 }

 impl Clone for Box<OsStr> {
     #[inline]
     fn clone(&self) -> Self {
         self.to_os_string().into_boxed_os_str()
     }
 }

 impl From<OsString> for Arc<OsStr> {
     /// Converts a [`OsString`] into a [`Arc`]`<OsStr>` without copying or allocating.
     ///
     /// [`Arc`]: ../sync/struct.Arc.html
     /// [`OsString`]: ../ffi/struct.OsString.html
     #[inline]
     fn from(s: OsString) -> Arc<OsStr> {
         let arc = s.inner.into_arc();
         unsafe { Arc::from_raw(Arc::into_raw(arc) as *const OsStr) }
     }
 }

 impl From<&OsStr> for Arc<OsStr> {
     #[inline]
     fn from(s: &OsStr) -> Arc<OsStr> {
         let arc = s.inner.into_arc();
         unsafe { Arc::from_raw(Arc::into_raw(arc) as *const OsStr) }
     }
 }

 impl From<OsString> for Rc<OsStr> {
     /// Converts a [`OsString`] into a [`Rc`]`<OsStr>` without copying or allocating.
     ///
     /// [`Rc`]: ../rc/struct.Rc.html
     /// [`OsString`]: ../ffi/struct.OsString.html
     #[inline]
     fn from(s: OsString) -> Rc<OsStr> {
         let rc = s.inner.into_rc();
         unsafe { Rc::from_raw(Rc::into_raw(rc) as *const OsStr) }
     }
 }

 impl From<&OsStr> for Rc<OsStr> {
     #[inline]
     fn from(s: &OsStr) -> Rc<OsStr> {
         let rc = s.inner.into_rc();
         unsafe { Rc::from_raw(Rc::into_raw(rc) as *const OsStr) }
     }
 }

 impl<'a> From<OsString> for Cow<'a, OsStr> {
     #[inline]
     fn from(s: OsString) -> Cow<'a, OsStr> {
         Cow::Owned(s)
     }
 }

 impl<'a> From<&'a OsStr> for Cow<'a, OsStr> {
     #[inline]
     fn from(s: &'a OsStr) -> Cow<'a, OsStr> {
         Cow::Borrowed(s)
     }
 }

 impl<'a> From<&'a OsString> for Cow<'a, OsStr> {
     #[inline]
     fn from(s: &'a OsString) -> Cow<'a, OsStr> {
         Cow::Borrowed(s.as_os_str())
     }
 }

 impl<'a> From<Cow<'a, OsStr>> for OsString {
     #[inline]
     fn from(s: Cow<'a, OsStr>) -> Self {
         s.into_owned()
     }
 }

 impl Default for Box<OsStr> {
     fn default() -> Box<OsStr> {
         let rw = Box::into_raw(Slice::empty_box()) as *mut OsStr;
         unsafe { Box::from_raw(rw) }
     }
 }

 impl Default for &OsStr {
     /// Creates an empty `OsStr`.
     #[inline]
     fn default() -> Self {
         OsStr::new("")
     }
 }

 impl PartialEq for OsStr {
     fn eq(&self, other: &OsStr) -> bool {
         self.bytes().eq(other.bytes())
     }
 }

 impl PartialEq<str> for OsStr {
     #[inline]
     fn eq(&self, other: &str) -> bool {
         *self == *OsStr::new(other)
     }
 }

 impl PartialEq<OsStr> for str {
     #[inline]
     fn eq(&self, other: &OsStr) -> bool {
         *other == *OsStr::new(self)
     }
 }

 impl Eq for OsStr {}

 impl PartialOrd for OsStr {
     #[inline]
     fn partial_cmp(&self, other: &OsStr) -> Option<cmp::Ordering> {
         self.bytes().partial_cmp(other.bytes())
     }
     #[inline]
     fn lt(&self, other: &OsStr) -> bool {
         self.bytes().lt(other.bytes())
     }
     #[inline]
     fn le(&self, other: &OsStr) -> bool {
         self.bytes().le(other.bytes())
     }
     #[inline]
     fn gt(&self, other: &OsStr) -> bool {
         self.bytes().gt(other.bytes())
     }
     #[inline]
     fn ge(&self, other: &OsStr) -> bool {
         self.bytes().ge(other.bytes())
     }
 }

 impl PartialOrd<str> for OsStr {
     #[inline]
     fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
         self.partial_cmp(OsStr::new(other))
     }
 }

 // FIXME (#19470): cannot provide PartialOrd<OsStr> for str until we
 // have more flexible coherence rules.

 impl Ord for OsStr {
     #[inline]
     fn cmp(&self, other: &OsStr) -> cmp::Ordering {
         self.bytes().cmp(other.bytes())
     }
 }

 macro_rules! impl_cmp {
     ($lhs:ty, $rhs: ty) => {
         impl<'a, 'b> PartialEq<$rhs> for $lhs {
             #[inline]
             fn eq(&self, other: &$rhs) -> bool {
                 <OsStr as PartialEq>::eq(self, other)
             }
         }

         impl<'a, 'b> PartialEq<$lhs> for $rhs {
             #[inline]
             fn eq(&self, other: &$lhs) -> bool {
                 <OsStr as PartialEq>::eq(self, other)
             }
         }

         impl<'a, 'b> PartialOrd<$rhs> for $lhs {
             #[inline]
             fn partial_cmp(&self, other: &$rhs) -> Option<cmp::Ordering> {
                 <OsStr as PartialOrd>::partial_cmp(self, other)
             }
         }

         impl<'a, 'b> PartialOrd<$lhs> for $rhs {
             #[inline]
             fn partial_cmp(&self, other: &$lhs) -> Option<cmp::Ordering> {
                 <OsStr as PartialOrd>::partial_cmp(self, other)
             }
         }
     };
 }

 impl_cmp!(OsString, OsStr);
 impl_cmp!(OsString, &'a OsStr);
 impl_cmp!(Cow<'a, OsStr>, OsStr);
 impl_cmp!(Cow<'a, OsStr>, &'b OsStr);
 impl_cmp!(Cow<'a, OsStr>, OsString);

 impl Hash for OsStr {
     #[inline]
     fn hash<H: Hasher>(&self, state: &mut H) {
         self.bytes().hash(state)
     }
 }

 impl fmt::Debug for OsStr {
     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&self.inner, formatter)
     }
 }

 impl OsStr {
     pub(crate) fn display(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&self.inner, formatter)
     }
 }

 impl Borrow<OsStr> for OsString {
     fn borrow(&self) -> &OsStr {
         &self[..]
     }
 }

 impl ToOwned for OsStr {
     type Owned = OsString;
     fn to_owned(&self) -> OsString {
         self.to_os_string()
     }
     fn clone_into(&self, target: &mut OsString) {
         self.inner.clone_into(&mut target.inner)
     }
 }

 impl AsRef<OsStr> for OsStr {
     fn as_ref(&self) -> &OsStr {
         self
     }
 }

 impl AsRef<OsStr> for OsString {
     #[inline]
     fn as_ref(&self) -> &OsStr {
         self
     }
 }

 impl AsRef<OsStr> for str {
     #[inline]
     fn as_ref(&self) -> &OsStr {
         OsStr::from_inner(Slice::from_str(self))
     }
 }

 impl AsRef<OsStr> for String {
     #[inline]
     fn as_ref(&self) -> &OsStr {
         (&**self).as_ref()
     }
 }

 impl FromInner<Buf> for OsString {
     fn from_inner(buf: Buf) -> OsString {
         OsString { inner: buf }
     }
 }

 impl IntoInner<Buf> for OsString {
     fn into_inner(self) -> Buf {
         self.inner
     }
 }

 impl AsInner<Slice> for OsStr {
     #[inline]
     fn as_inner(&self) -> &Slice {
         &self.inner
     }
 }
	// Licensed to the Apache Software Foundation (ASF) under one
	// or more contributor license agreements. See the NOTICE file
	// distributed with this work for additional information
	// regarding copyright ownership. The ASF licenses this file
	// to you under the Apache License, Version 2.0 (the
	// "License"); you may not use this file except in compliance
	// with the License. You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing,
	// software distributed under the License is distributed on an
	// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	// KIND, either express or implied. See the License for the
	// specific language governing permissions and limitations
	// under the License..

	use crate::sys::os_str::{Buf, Slice};
	use crate::sys_common::{AsInner, FromInner, IntoInner};
	use core::ops;
	use core::cmp;
	use core::hash::{Hash, Hasher};
	use core::fmt;
	use alloc_crate::borrow::{Borrow, Cow, ToOwned};
	use alloc_crate::string::String;
	use alloc_crate::boxed::Box;
	use alloc_crate::rc::Rc;
	use alloc_crate::sync::Arc;


	/// A type that can represent owned, mutable platform-native strings, but is
	/// cheaply inter-convertible with Rust strings.
	///
	#[derive(Clone)]
	pub struct OsString {
	inner: Buf,
	}

	/// Borrowed reference to an OS string (see [`OsString`]).
	///
	/// This type represents a borrowed reference to a string in the operating system's preferred
	/// representation.
	///
	/// `&OsStr` is to [`OsString`] as [`&str`] is to [`String`]: the former in each pair are borrowed
	/// references; the latter are owned strings.
	///
	/// See the [module's toplevel documentation about conversions][conversions] for a discussion on
	/// the traits which `OsStr` implements for [conversions] from/to native representations.
	///
	/// [`OsString`]: struct.OsString.html
	/// [`&str`]: ../primitive.str.html
	/// [`String`]: ../string/struct.String.html
	/// [conversions]: index.html#conversions
	pub struct OsStr {
	inner: Slice,
	}

	impl OsString {
	/// Constructs a new empty `OsString`.
	///
	pub fn new() -> OsString {
	OsString { inner: Buf::from_string(String::new()) }
	}

	/// Converts to an [`OsStr`] slice.
	///
	/// [`OsStr`]: struct.OsStr.html
	///
	pub fn as_os_str(&self) -> &OsStr {
	self
	}

	/// Converts the `OsString` into a [`String`] if it contains valid Unicode data.
	///
	/// On failure, ownership of the original `OsString` is returned.
	///
	/// [`String`]: ../../std/string/struct.String.html
	///
	pub fn into_string(self) -> Result<String, OsString> {
	self.inner.into_string().map_err(\|buf\| OsString { inner: buf })
	}

	/// Extends the string with the given [`&OsStr`] slice.
	///
	/// [`&OsStr`]: struct.OsStr.html
	///
	pub fn push<T: AsRef<OsStr>>(&mut self, s: T) {
	self.inner.push_slice(&s.as_ref().inner)
	}

	/// Creates a new `OsString` with the given capacity.
	///
	/// The string will be able to hold exactly `capacity` length units of other
	/// OS strings without reallocating. If `capacity` is 0, the string will not
	/// allocate.
	///
	/// See main `OsString` documentation information about encoding.
	///
	pub fn with_capacity(capacity: usize) -> OsString {
	OsString { inner: Buf::with_capacity(capacity) }
	}

	/// Truncates the `OsString` to zero length.
	///
	pub fn clear(&mut self) {
	self.inner.clear()
	}

	/// Returns the capacity this `OsString` can hold without reallocating.
	///
	/// See `OsString` introduction for information about encoding.
	///
	pub fn capacity(&self) -> usize {
	self.inner.capacity()
	}

	/// Reserves capacity for at least `additional` more capacity to be inserted
	/// in the given `OsString`.
	///
	/// The collection may reserve more space to avoid frequent reallocations.
	///
	pub fn reserve(&mut self, additional: usize) {
	self.inner.reserve(additional)
	}

	/// Reserves the minimum capacity for exactly `additional` more capacity to
	/// be inserted in the given `OsString`. Does nothing if the capacity is
	/// already sufficient.
	///
	/// Note that the allocator may give the collection more space than it
	/// requests. Therefore, capacity can not be relied upon to be precisely
	/// minimal. Prefer reserve if future insertions are expected.
	///
	pub fn reserve_exact(&mut self, additional: usize) {
	self.inner.reserve_exact(additional)
	}

	/// Shrinks the capacity of the `OsString` to match its length.
	///
	pub fn shrink_to_fit(&mut self) {
	self.inner.shrink_to_fit()
	}

	/// Shrinks the capacity of the `OsString` with a lower bound.
	///
	/// The capacity will remain at least as large as both the length
	/// and the supplied value.
	///
	/// Panics if the current capacity is smaller than the supplied
	/// minimum capacity.
	///
	#[inline]
	pub fn shrink_to(&mut self, min_capacity: usize) {
	self.inner.shrink_to(min_capacity)
	}

	/// Converts this `OsString` into a boxed [`OsStr`].
	///
	/// [`OsStr`]: struct.OsStr.html
	///
	pub fn into_boxed_os_str(self) -> Box<OsStr> {
	let rw = Box::into_raw(self.inner.into_box()) as *mut OsStr;
	unsafe { Box::from_raw(rw) }
	}
	}

	impl From<String> for OsString {
	/// Converts a [`String`] into a [`OsString`].
	///
	/// The conversion copies the data, and includes an allocation on the heap.
	///
	/// [`OsString`]: ../../std/ffi/struct.OsString.html
	fn from(s: String) -> OsString {
	OsString { inner: Buf::from_string(s) }
	}
	}

	impl<T: ?Sized + AsRef<OsStr>> From<&T> for OsString {
	fn from(s: &T) -> OsString {
	s.as_ref().to_os_string()
	}
	}

	impl ops::Index<ops::RangeFull> for OsString {
	type Output = OsStr;

	#[inline]
	fn index(&self, _index: ops::RangeFull) -> &OsStr {
	OsStr::from_inner(self.inner.as_slice())
	}
	}

	impl ops::IndexMut<ops::RangeFull> for OsString {
	#[inline]
	fn index_mut(&mut self, _index: ops::RangeFull) -> &mut OsStr {
	OsStr::from_inner_mut(self.inner.as_mut_slice())
	}
	}

	impl ops::Deref for OsString {
	type Target = OsStr;

	#[inline]
	fn deref(&self) -> &OsStr {
	&self[..]
	}
	}

	impl ops::DerefMut for OsString {
	#[inline]
	fn deref_mut(&mut self) -> &mut OsStr {
	&mut self[..]
	}
	}

	impl Default for OsString {
	/// Constructs an empty `OsString`.
	#[inline]
	fn default() -> OsString {
	OsString::new()
	}
	}

	impl fmt::Debug for OsString {
	fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
	fmt::Debug::fmt(&**self, formatter)
	}
	}

	impl PartialEq for OsString {
	fn eq(&self, other: &OsString) -> bool {
	&self == &other
	}
	}

	impl PartialEq<str> for OsString {
	fn eq(&self, other: &str) -> bool {
	&**self == other
	}
	}

	impl PartialEq<OsString> for str {
	fn eq(&self, other: &OsString) -> bool {
	&**other == self
	}
	}

	impl PartialEq<&str> for OsString {
	fn eq(&self, other: &&str) -> bool {
	self == other
	}
	}

	impl<'a> PartialEq<OsString> for &'a str {
	fn eq(&self, other: &OsString) -> bool {
	other == self
	}
	}

	impl Eq for OsString {}

	impl PartialOrd for OsString {
	#[inline]
	fn partial_cmp(&self, other: &OsString) -> Option<cmp::Ordering> {
	(&self).partial_cmp(&other)
	}
	#[inline]
	fn lt(&self, other: &OsString) -> bool {
	&self < &other
	}
	#[inline]
	fn le(&self, other: &OsString) -> bool {
	&self <= &other
	}
	#[inline]
	fn gt(&self, other: &OsString) -> bool {
	&self > &other
	}
	#[inline]
	fn ge(&self, other: &OsString) -> bool {
	&self >= &other
	}
	}

	impl PartialOrd<str> for OsString {
	#[inline]
	fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
	(&**self).partial_cmp(other)
	}
	}

	impl Ord for OsString {
	#[inline]
	fn cmp(&self, other: &OsString) -> cmp::Ordering {
	(&self).cmp(&other)
	}
	}

	impl Hash for OsString {
	#[inline]
	fn hash<H: Hasher>(&self, state: &mut H) {
	(&**self).hash(state)
	}
	}

	impl OsStr {
	/// Coerces into an `OsStr` slice.
	///
	pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &OsStr {
	s.as_ref()
	}

	#[inline]
	fn from_inner(inner: &Slice) -> &OsStr {
	// Safety: OsStr is just a wrapper of Slice,
	// therefore converting &Slice to &OsStr is safe.
	unsafe { &(inner as const Slice as *const OsStr) }
	}

	#[inline]
	fn from_inner_mut(inner: &mut Slice) -> &mut OsStr {
	// Safety: OsStr is just a wrapper of Slice,
	// therefore converting &mut Slice to &mut OsStr is safe.
	// Any method that mutates OsStr must be careful not to
	// break platform-specific encoding, in particular Wtf8 on Windows.
	unsafe { &mut (inner as mut Slice as *mut OsStr) }
	}

	/// Yields a [`&str`] slice if the `OsStr` is valid Unicode.
	///
	/// This conversion may entail doing a check for UTF-8 validity.
	///
	/// [`&str`]: ../../std/primitive.str.html
	///
	pub fn to_str(&self) -> Option<&str> {
	self.inner.to_str()
	}

	/// Converts an `OsStr` to a [`Cow`]`<`[`str`]`>`.
	///
	/// Any non-Unicode sequences are replaced with
	/// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD].
	///
	/// [`Cow`]: ../../std/borrow/enum.Cow.html
	/// [`str`]: ../../std/primitive.str.html
	/// [U+FFFD]: ../../std/char/constant.REPLACEMENT_CHARACTER.html
	///
	pub fn to_string_lossy(&self) -> Cow<'_, str> {
	self.inner.to_string_lossy()
	}

	/// Copies the slice into an owned [`OsString`].
	///
	/// [`OsString`]: struct.OsString.html
	///
	pub fn to_os_string(&self) -> OsString {
	OsString { inner: self.inner.to_owned() }
	}

	/// Checks whether the `OsStr` is empty.
	///
	pub fn is_empty(&self) -> bool {
	self.inner.inner.is_empty()
	}

	/// Returns the length of this `OsStr`.
	///
	/// Note that this does not return the number of bytes in the string in
	/// OS string form.
	///
	/// The length returned is that of the underlying storage used by `OsStr`.
	/// As discussed in the [`OsString`] introduction, [`OsString`] and `OsStr`
	/// store strings in a form best suited for cheap inter-conversion between
	/// native-platform and Rust string forms, which may differ significantly
	/// from both of them, including in storage size and encoding.
	///
	/// This number is simply useful for passing to other methods, like
	/// [`OsString::with_capacity`] to avoid reallocations.
	///
	/// [`OsString`]: struct.OsString.html
	/// [`OsString::with_capacity`]: struct.OsString.html#method.with_capacity
	///
	pub fn len(&self) -> usize {
	self.inner.inner.len()
	}

	/// Converts a [`Box`]`<OsStr>` into an [`OsString`] without copying or allocating.
	///
	/// [`Box`]: ../boxed/struct.Box.html
	/// [`OsString`]: struct.OsString.html
	pub fn into_os_string(self: Box<OsStr>) -> OsString {
	let boxed = unsafe { Box::from_raw(Box::into_raw(self) as *mut Slice) };
	OsString { inner: Buf::from_box(boxed) }
	}

	/// Gets the underlying byte representation.
	///
	/// Note: it is crucial that this API is private, to avoid
	/// revealing the internal, platform-specific encodings.
	#[inline]
	fn bytes(&self) -> &[u8] {
	unsafe { &(&self.inner as const _ as *const [u8]) }
	}

	/// Converts this string to its ASCII lower case equivalent in-place.
	///
	/// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
	/// but non-ASCII letters are unchanged.
	///
	/// To return a new lowercased value without modifying the existing one, use
	/// [`to_ascii_lowercase`].
	///
	/// [`to_ascii_lowercase`]: #method.to_ascii_lowercase
	///
	pub fn make_ascii_lowercase(&mut self) {
	self.inner.make_ascii_lowercase()
	}

	/// Converts this string to its ASCII upper case equivalent in-place.
	///
	/// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
	/// but non-ASCII letters are unchanged.
	///
	/// To return a new uppercased value without modifying the existing one, use
	/// [`to_ascii_uppercase`].
	///
	/// [`to_ascii_uppercase`]: #method.to_ascii_uppercase
	///
	pub fn make_ascii_uppercase(&mut self) {
	self.inner.make_ascii_uppercase()
	}

	/// Returns a copy of this string where each character is mapped to its
	/// ASCII lower case equivalent.
	///
	/// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
	/// but non-ASCII letters are unchanged.
	///
	/// To lowercase the value in-place, use [`make_ascii_lowercase`].
	///
	/// [`make_ascii_lowercase`]: #method.make_ascii_lowercase
	///
	pub fn to_ascii_lowercase(&self) -> OsString {
	OsString::from_inner(self.inner.to_ascii_lowercase())
	}

	/// Returns a copy of this string where each character is mapped to its
	/// ASCII upper case equivalent.
	///
	/// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
	/// but non-ASCII letters are unchanged.
	///
	/// To uppercase the value in-place, use [`make_ascii_uppercase`].
	///
	/// [`make_ascii_uppercase`]: #method.make_ascii_uppercase
	///
	pub fn to_ascii_uppercase(&self) -> OsString {
	OsString::from_inner(self.inner.to_ascii_uppercase())
	}

	/// Checks if all characters in this string are within the ASCII range.
	///
	pub fn is_ascii(&self) -> bool {
	self.inner.is_ascii()
	}

	/// Checks that two strings are an ASCII case-insensitive match.
	///
	/// Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`,
	/// but without allocating and copying temporaries.
	///
	pub fn eq_ignore_ascii_case<S: ?Sized + AsRef<OsStr>>(&self, other: &S) -> bool {
	self.inner.eq_ignore_ascii_case(&other.as_ref().inner)
	}
	}

	impl From<&OsStr> for Box<OsStr> {
	fn from(s: &OsStr) -> Box<OsStr> {
	let rw = Box::into_raw(s.inner.into_box()) as *mut OsStr;
	unsafe { Box::from_raw(rw) }
	}
	}

	impl From<Box<OsStr>> for OsString {
	/// Converts a [`Box`]`<`[`OsStr`]`>` into a `OsString` without copying or
	/// allocating.
	///
	/// [`Box`]: ../boxed/struct.Box.html
	/// [`OsStr`]: ../ffi/struct.OsStr.html
	fn from(boxed: Box<OsStr>) -> OsString {
	boxed.into_os_string()
	}
	}

	impl From<OsString> for Box<OsStr> {
	/// Converts a [`OsString`] into a [`Box`]`<OsStr>` without copying or allocating.
	///
	/// [`Box`]: ../boxed/struct.Box.html
	/// [`OsString`]: ../ffi/struct.OsString.html
	fn from(s: OsString) -> Box<OsStr> {
	s.into_boxed_os_str()
	}
	}

	impl Clone for Box<OsStr> {
	#[inline]
	fn clone(&self) -> Self {
	self.to_os_string().into_boxed_os_str()
	}
	}

	impl From<OsString> for Arc<OsStr> {
	/// Converts a [`OsString`] into a [`Arc`]`<OsStr>` without copying or allocating.
	///
	/// [`Arc`]: ../sync/struct.Arc.html
	/// [`OsString`]: ../ffi/struct.OsString.html
	#[inline]
	fn from(s: OsString) -> Arc<OsStr> {
	let arc = s.inner.into_arc();
	unsafe { Arc::from_raw(Arc::into_raw(arc) as *const OsStr) }
	}
	}

	impl From<&OsStr> for Arc<OsStr> {
	#[inline]
	fn from(s: &OsStr) -> Arc<OsStr> {
	let arc = s.inner.into_arc();
	unsafe { Arc::from_raw(Arc::into_raw(arc) as *const OsStr) }
	}
	}

	impl From<OsString> for Rc<OsStr> {
	/// Converts a [`OsString`] into a [`Rc`]`<OsStr>` without copying or allocating.
	///
	/// [`Rc`]: ../rc/struct.Rc.html
	/// [`OsString`]: ../ffi/struct.OsString.html
	#[inline]
	fn from(s: OsString) -> Rc<OsStr> {
	let rc = s.inner.into_rc();
	unsafe { Rc::from_raw(Rc::into_raw(rc) as *const OsStr) }
	}
	}

	impl From<&OsStr> for Rc<OsStr> {
	#[inline]
	fn from(s: &OsStr) -> Rc<OsStr> {
	let rc = s.inner.into_rc();
	unsafe { Rc::from_raw(Rc::into_raw(rc) as *const OsStr) }
	}
	}

	impl<'a> From<OsString> for Cow<'a, OsStr> {
	#[inline]
	fn from(s: OsString) -> Cow<'a, OsStr> {
	Cow::Owned(s)
	}
	}

	impl<'a> From<&'a OsStr> for Cow<'a, OsStr> {
	#[inline]
	fn from(s: &'a OsStr) -> Cow<'a, OsStr> {
	Cow::Borrowed(s)
	}
	}

	impl<'a> From<&'a OsString> for Cow<'a, OsStr> {
	#[inline]
	fn from(s: &'a OsString) -> Cow<'a, OsStr> {
	Cow::Borrowed(s.as_os_str())
	}
	}

	impl<'a> From<Cow<'a, OsStr>> for OsString {
	#[inline]
	fn from(s: Cow<'a, OsStr>) -> Self {
	s.into_owned()
	}
	}

	impl Default for Box<OsStr> {
	fn default() -> Box<OsStr> {
	let rw = Box::into_raw(Slice::empty_box()) as *mut OsStr;
	unsafe { Box::from_raw(rw) }
	}
	}

	impl Default for &OsStr {
	/// Creates an empty `OsStr`.
	#[inline]
	fn default() -> Self {
	OsStr::new("")
	}
	}

	impl PartialEq for OsStr {
	fn eq(&self, other: &OsStr) -> bool {
	self.bytes().eq(other.bytes())
	}
	}

	impl PartialEq<str> for OsStr {
	#[inline]
	fn eq(&self, other: &str) -> bool {
	self == OsStr::new(other)
	}
	}

	impl PartialEq<OsStr> for str {
	#[inline]
	fn eq(&self, other: &OsStr) -> bool {
	other == OsStr::new(self)
	}
	}

	impl Eq for OsStr {}

	impl PartialOrd for OsStr {
	#[inline]
	fn partial_cmp(&self, other: &OsStr) -> Option<cmp::Ordering> {
	self.bytes().partial_cmp(other.bytes())
	}
	#[inline]
	fn lt(&self, other: &OsStr) -> bool {
	self.bytes().lt(other.bytes())
	}
	#[inline]
	fn le(&self, other: &OsStr) -> bool {
	self.bytes().le(other.bytes())
	}
	#[inline]
	fn gt(&self, other: &OsStr) -> bool {
	self.bytes().gt(other.bytes())
	}
	#[inline]
	fn ge(&self, other: &OsStr) -> bool {
	self.bytes().ge(other.bytes())
	}
	}

	impl PartialOrd<str> for OsStr {
	#[inline]
	fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
	self.partial_cmp(OsStr::new(other))
	}
	}

	// FIXME (#19470): cannot provide PartialOrd<OsStr> for str until we
	// have more flexible coherence rules.

	impl Ord for OsStr {
	#[inline]
	fn cmp(&self, other: &OsStr) -> cmp::Ordering {
	self.bytes().cmp(other.bytes())
	}
	}

	macro_rules! impl_cmp {
	($lhs:ty, $rhs: ty) => {
	impl<'a, 'b> PartialEq<$rhs> for $lhs {
	#[inline]
	fn eq(&self, other: &$rhs) -> bool {
	<OsStr as PartialEq>::eq(self, other)
	}
	}

	impl<'a, 'b> PartialEq<$lhs> for $rhs {
	#[inline]
	fn eq(&self, other: &$lhs) -> bool {
	<OsStr as PartialEq>::eq(self, other)
	}
	}

	impl<'a, 'b> PartialOrd<$rhs> for $lhs {
	#[inline]
	fn partial_cmp(&self, other: &$rhs) -> Option<cmp::Ordering> {
	<OsStr as PartialOrd>::partial_cmp(self, other)
	}
	}

	impl<'a, 'b> PartialOrd<$lhs> for $rhs {
	#[inline]
	fn partial_cmp(&self, other: &$lhs) -> Option<cmp::Ordering> {
	<OsStr as PartialOrd>::partial_cmp(self, other)
	}
	}
	};
	}

	impl_cmp!(OsString, OsStr);
	impl_cmp!(OsString, &'a OsStr);
	impl_cmp!(Cow<'a, OsStr>, OsStr);
	impl_cmp!(Cow<'a, OsStr>, &'b OsStr);
	impl_cmp!(Cow<'a, OsStr>, OsString);

	impl Hash for OsStr {
	#[inline]
	fn hash<H: Hasher>(&self, state: &mut H) {
	self.bytes().hash(state)
	}
	}

	impl fmt::Debug for OsStr {
	fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
	fmt::Debug::fmt(&self.inner, formatter)
	}
	}

	impl OsStr {
	pub(crate) fn display(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
	fmt::Display::fmt(&self.inner, formatter)
	}
	}

	impl Borrow<OsStr> for OsString {
	fn borrow(&self) -> &OsStr {
	&self[..]
	}
	}

	impl ToOwned for OsStr {
	type Owned = OsString;
	fn to_owned(&self) -> OsString {
	self.to_os_string()
	}
	fn clone_into(&self, target: &mut OsString) {
	self.inner.clone_into(&mut target.inner)
	}
	}

	impl AsRef<OsStr> for OsStr {
	fn as_ref(&self) -> &OsStr {
	self
	}
	}

	impl AsRef<OsStr> for OsString {
	#[inline]
	fn as_ref(&self) -> &OsStr {
	self
	}
	}

	impl AsRef<OsStr> for str {
	#[inline]
	fn as_ref(&self) -> &OsStr {
	OsStr::from_inner(Slice::from_str(self))
	}
	}

	impl AsRef<OsStr> for String {
	#[inline]
	fn as_ref(&self) -> &OsStr {
	(&**self).as_ref()
	}
	}

	impl FromInner<Buf> for OsString {
	fn from_inner(buf: Buf) -> OsString {
	OsString { inner: buf }
	}
	}

	impl IntoInner<Buf> for OsString {
	fn into_inner(self) -> Buf {
	self.inner
	}
	}

	impl AsInner<Slice> for OsStr {
	#[inline]
	fn as_inner(&self) -> &Slice {
	&self.inner
	}
	}