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    // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
    // file at the top-level directory of this distribution and at
    // http://rust-lang.org/COPYRIGHT.
    //
    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.

    use borrow::{Borrow, Cow};
    use fmt;
    use ops;
    use cmp;
    use hash::{Hash, Hasher};
    use rc::Rc;
    use sync::Arc;

    use sys::os_str::{Buf, Slice};
    use sys_common::{AsInner, IntoInner, FromInner};

    /// A type that can represent owned, mutable platform-native strings, but is
    /// cheaply inter-convertible with Rust strings.
    ///
    /// The need for this type arises from the fact that:
    ///
    /// * On Unix systems, strings are often arbitrary sequences of non-zero
    ///   bytes, in many cases interpreted as UTF-8.
    ///
    /// * On Windows, strings are often arbitrary sequences of non-zero 16-bit
    ///   values, interpreted as UTF-16 when it is valid to do so.
    ///
    /// * In Rust, strings are always valid UTF-8, which may contain zeros.
    ///
    /// `OsString` and [`OsStr`] bridge this gap by simultaneously representing Rust
    /// and platform-native string values, and in particular allowing a Rust string
    /// to be converted into an "OS" string with no cost if possible.
    ///
    /// `OsString` is to [`&OsStr`] as [`String`] is to [`&str`]: the former
    /// in each pair are owned strings; the latter are borrowed
    /// references.
    ///
    /// # Creating an `OsString`
    ///
    /// **From a Rust string**: `OsString` implements
    /// [`From`]`<`[`String`]`>`, so you can use `my_string.from` to
    /// create an `OsString` from a normal Rust string.
    ///
    /// **From slices:** Just like you can start with an empty Rust
    /// [`String`] and then [`push_str`][String.push_str] `&str`
    /// sub-string slices into it, you can create an empty `OsString` with
    /// the [`new`] method and then push string slices into it with the
    /// [`push`] method.
    ///
    /// # Extracting a borrowed reference to the whole OS string
    ///
    /// You can use the [`as_os_str`] method to get an `&`[`OsStr`] from
    /// an `OsString`; this is effectively a borrowed reference to the
    /// whole string.
    ///
    /// # Conversions
    ///
    /// See the [module's toplevel documentation about conversions][conversions] for a discussion on
    /// the traits which `OsString` implements for [conversions] from/to native representations.
    ///
    /// [`OsStr`]: struct.OsStr.html
    /// [`&OsStr`]: struct.OsStr.html
    /// [`From`]: ../convert/trait.From.html
    /// [`String`]: ../string/struct.String.html
    /// [`&str`]: ../primitive.str.html
    /// [`u8`]: ../primitive.u8.html
    /// [`u16`]: ../primitive.u16.html
    /// [String.push_str]: ../string/struct.String.html#method.push_str
    /// [`new`]: #method.new
    /// [`push`]: #method.push
    /// [`as_os_str`]: #method.as_os_str
    /// [conversions]: index.html#conversions
    #[derive(Clone)]
    #[stable(feature = "rust1", since = "1.0.0")]
    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
    #[stable(feature = "rust1", since = "1.0.0")]
    pub struct OsStr {
        inner: Slice
    }

    impl OsString {
        /// Constructs a new empty `OsString`.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let os_string = OsString::new();
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        pub fn new() -> OsString {
            OsString { inner: Buf::from_string(String::new()) }
        }

        /// Converts to an [`OsStr`] slice.
        ///
        /// [`OsStr`]: struct.OsStr.html
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::{OsString, OsStr};
        ///
        /// let os_string = OsString::from("foo");
        /// let os_str = OsStr::new("foo");
        /// assert_eq!(os_string.as_os_str(), os_str);
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        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
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let os_string = OsString::from("foo");
        /// let string = os_string.into_string();
        /// assert_eq!(string, Ok(String::from("foo")));
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        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
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut os_string = OsString::from("foo");
        /// os_string.push("bar");
        /// assert_eq!(&os_string, "foobar");
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        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.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut os_string = OsString::with_capacity(10);
        /// let capacity = os_string.capacity();
        ///
        /// // This push is done without reallocating
        /// os_string.push("foo");
        ///
        /// assert_eq!(capacity, os_string.capacity());
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        pub fn with_capacity(capacity: usize) -> OsString {
            OsString {
                inner: Buf::with_capacity(capacity)
            }
        }

        /// Truncates the `OsString` to zero length.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut os_string = OsString::from("foo");
        /// assert_eq!(&os_string, "foo");
        ///
        /// os_string.clear();
        /// assert_eq!(&os_string, "");
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        pub fn clear(&mut self) {
            self.inner.clear()
        }

        /// Returns the capacity this `OsString` can hold without reallocating.
        ///
        /// See `OsString` introduction for information about encoding.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut os_string = OsString::with_capacity(10);
        /// assert!(os_string.capacity() >= 10);
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        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.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut s = OsString::new();
        /// s.reserve(10);
        /// assert!(s.capacity() >= 10);
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        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.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut s = OsString::new();
        /// s.reserve_exact(10);
        /// assert!(s.capacity() >= 10);
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        pub fn reserve_exact(&mut self, additional: usize) {
            self.inner.reserve_exact(additional)
        }

        /// Shrinks the capacity of the `OsString` to match its length.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsString;
        ///
        /// let mut s = OsString::from("foo");
        ///
        /// s.reserve(100);
        /// assert!(s.capacity() >= 100);
        ///
        /// s.shrink_to_fit();
        /// assert_eq!(3, s.capacity());
        /// ```
        #[stable(feature = "osstring_shrink_to_fit", since = "1.19.0")]
        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.
        ///
        /// # Examples
        ///
        /// ```
        /// #![feature(shrink_to)]
        /// use std::ffi::OsString;
        ///
        /// let mut s = OsString::from("foo");
        ///
        /// s.reserve(100);
        /// assert!(s.capacity() >= 100);
        ///
        /// s.shrink_to(10);
        /// assert!(s.capacity() >= 10);
        /// s.shrink_to(0);
        /// assert!(s.capacity() >= 3);
        /// ```
        #[inline]
        #[unstable(feature = "shrink_to", reason = "new API", issue="0")]
        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
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::{OsString, OsStr};
        ///
        /// let s = OsString::from("hello");
        ///
        /// let b: Box<OsStr> = s.into_boxed_os_str();
        /// ```
        #[stable(feature = "into_boxed_os_str", since = "1.20.0")]
        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) }
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl From<String> for OsString {
        fn from(s: String) -> OsString {
            OsString { inner: Buf::from_string(s) }
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl<'a, T: ?Sized + AsRef<OsStr>> From<&'a T> for OsString {
        fn from(s: &'a T) -> OsString {
            s.as_ref().to_os_string()
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    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())
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl ops::Deref for OsString {
        type Target = OsStr;

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

    #[stable(feature = "osstring_default", since = "1.9.0")]
    impl Default for OsString {
        /// Constructs an empty `OsString`.
        #[inline]
        fn default() -> OsString {
            OsString::new()
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl fmt::Debug for OsString {
        fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
            fmt::Debug::fmt(&**self, formatter)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialEq for OsString {
        fn eq(&self, other: &OsString) -> bool {
            &**self == &**other
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialEq<str> for OsString {
        fn eq(&self, other: &str) -> bool {
            &**self == other
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialEq<OsString> for str {
        fn eq(&self, other: &OsString) -> bool {
            &**other == self
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Eq for OsString {}

    #[stable(feature = "rust1", since = "1.0.0")]
    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 }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialOrd<str> for OsString {
        #[inline]
        fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
            (&**self).partial_cmp(other)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Ord for OsString {
        #[inline]
        fn cmp(&self, other: &OsString) -> cmp::Ordering {
            (&**self).cmp(&**other)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Hash for OsString {
        #[inline]
        fn hash<H: Hasher>(&self, state: &mut H) {
            (&**self).hash(state)
        }
    }

    impl OsStr {
        /// Coerces into an `OsStr` slice.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsStr;
        ///
        /// let os_str = OsStr::new("foo");
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &OsStr {
            s.as_ref()
        }

        fn from_inner(inner: &Slice) -> &OsStr {
            unsafe { &*(inner as *const Slice as *const 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
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsStr;
        ///
        /// let os_str = OsStr::new("foo");
        /// assert_eq!(os_str.to_str(), Some("foo"));
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        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.
        ///
        /// [`Cow`]: ../../std/borrow/enum.Cow.html
        /// [`str`]: ../../std/primitive.str.html
        ///
        /// # Examples
        ///
        /// Calling `to_string_lossy` on an `OsStr` with valid unicode:
        ///
        /// ```
        /// use std::ffi::OsStr;
        ///
        /// let os_str = OsStr::new("foo");
        /// assert_eq!(os_str.to_string_lossy(), "foo");
        /// ```
        ///
        /// Had `os_str` contained invalid unicode, the `to_string_lossy` call might
        /// have returned `"fo�"`.
        #[stable(feature = "rust1", since = "1.0.0")]
        pub fn to_string_lossy(&self) -> Cow<str> {
            self.inner.to_string_lossy()
        }

        /// Copies the slice into an owned [`OsString`].
        ///
        /// [`OsString`]: struct.OsString.html
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::{OsStr, OsString};
        ///
        /// let os_str = OsStr::new("foo");
        /// let os_string = os_str.to_os_string();
        /// assert_eq!(os_string, OsString::from("foo"));
        /// ```
        #[stable(feature = "rust1", since = "1.0.0")]
        pub fn to_os_string(&self) -> OsString {
            OsString { inner: self.inner.to_owned() }
        }

        /// Checks whether the `OsStr` is empty.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsStr;
        ///
        /// let os_str = OsStr::new("");
        /// assert!(os_str.is_empty());
        ///
        /// let os_str = OsStr::new("foo");
        /// assert!(!os_str.is_empty());
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        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 this string
        /// as, for example, OS strings on Windows are encoded as a list of [`u16`]
        /// rather than a list of bytes. This number is simply useful for passing to
        /// other methods like [`OsString::with_capacity`] to avoid reallocations.
        ///
        /// See `OsStr` introduction for more information about encoding.
        ///
        /// [`u16`]: ../primitive.u16.html
        /// [`OsString::with_capacity`]: struct.OsString.html#method.with_capacity
        ///
        /// # Examples
        ///
        /// ```
        /// use std::ffi::OsStr;
        ///
        /// let os_str = OsStr::new("");
        /// assert_eq!(os_str.len(), 0);
        ///
        /// let os_str = OsStr::new("foo");
        /// assert_eq!(os_str.len(), 3);
        /// ```
        #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
        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
        #[stable(feature = "into_boxed_os_str", since = "1.20.0")]
        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.
        fn bytes(&self) -> &[u8] {
            unsafe { &*(&self.inner as *const _ as *const [u8]) }
        }
    }

    #[stable(feature = "box_from_os_str", since = "1.17.0")]
    impl<'a> From<&'a OsStr> for Box<OsStr> {
        fn from(s: &'a OsStr) -> Box<OsStr> {
            let rw = Box::into_raw(s.inner.into_box()) as *mut OsStr;
            unsafe { Box::from_raw(rw) }
        }
    }

    #[stable(feature = "os_string_from_box", since = "1.18.0")]
    impl From<Box<OsStr>> for OsString {
        fn from(boxed: Box<OsStr>) -> OsString {
            boxed.into_os_string()
        }
    }

    #[stable(feature = "box_from_os_string", since = "1.20.0")]
    impl From<OsString> for Box<OsStr> {
        fn from(s: OsString) -> Box<OsStr> {
            s.into_boxed_os_str()
        }
    }

    #[stable(feature = "shared_from_slice2", since = "1.24.0")]
    impl From<OsString> for Arc<OsStr> {
        #[inline]
        fn from(s: OsString) -> Arc<OsStr> {
            let arc = s.inner.into_arc();
            unsafe { Arc::from_raw(Arc::into_raw(arc) as *const OsStr) }
        }
    }

    #[stable(feature = "shared_from_slice2", since = "1.24.0")]
    impl<'a> From<&'a 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) }
        }
    }

    #[stable(feature = "shared_from_slice2", since = "1.24.0")]
    impl From<OsString> for Rc<OsStr> {
        #[inline]
        fn from(s: OsString) -> Rc<OsStr> {
            let rc = s.inner.into_rc();
            unsafe { Rc::from_raw(Rc::into_raw(rc) as *const OsStr) }
        }
    }

    #[stable(feature = "shared_from_slice2", since = "1.24.0")]
    impl<'a> From<&'a 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) }
        }
    }

    #[stable(feature = "cow_from_osstr", since = "1.28.0")]
    impl<'a> From<OsString> for Cow<'a, OsStr> {
        #[inline]
        fn from(s: OsString) -> Cow<'a, OsStr> {
            Cow::Owned(s)
        }
    }

    #[stable(feature = "cow_from_osstr", since = "1.28.0")]
    impl<'a> From<&'a OsStr> for Cow<'a, OsStr> {
        #[inline]
        fn from(s: &'a OsStr) -> Cow<'a, OsStr> {
            Cow::Borrowed(s)
        }
    }

    #[stable(feature = "cow_from_osstr", since = "1.28.0")]
    impl<'a> From<&'a OsString> for Cow<'a, OsStr> {
        #[inline]
        fn from(s: &'a OsString) -> Cow<'a, OsStr> {
            Cow::Borrowed(s.as_os_str())
        }
    }

    #[stable(feature = "osstring_from_cow_osstr", since = "1.28.0")]
    impl<'a> From<Cow<'a, OsStr>> for OsString {
        #[inline]
        fn from(s: Cow<'a, OsStr>) -> Self {
            s.into_owned()
        }
    }

    #[stable(feature = "box_default_extra", since = "1.17.0")]
    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) }
        }
    }

    #[stable(feature = "osstring_default", since = "1.9.0")]
    impl<'a> Default for &'a OsStr {
        /// Creates an empty `OsStr`.
        #[inline]
        fn default() -> &'a OsStr {
            OsStr::new("")
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialEq for OsStr {
        fn eq(&self, other: &OsStr) -> bool {
            self.bytes().eq(other.bytes())
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialEq<str> for OsStr {
        fn eq(&self, other: &str) -> bool {
            *self == *OsStr::new(other)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl PartialEq<OsStr> for str {
        fn eq(&self, other: &OsStr) -> bool {
            *other == *OsStr::new(self)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Eq for OsStr {}

    #[stable(feature = "rust1", since = "1.0.0")]
    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()) }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    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.

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Ord for OsStr {
        #[inline]
        fn cmp(&self, other: &OsStr) -> cmp::Ordering { self.bytes().cmp(other.bytes()) }
    }

    macro_rules! impl_cmp {
        ($lhs:ty, $rhs: ty) => {
            #[stable(feature = "cmp_os_str", since = "1.8.0")]
            impl<'a, 'b> PartialEq<$rhs> for $lhs {
                #[inline]
                fn eq(&self, other: &$rhs) -> bool { <OsStr as PartialEq>::eq(self, other) }
            }

            #[stable(feature = "cmp_os_str", since = "1.8.0")]
            impl<'a, 'b> PartialEq<$lhs> for $rhs {
                #[inline]
                fn eq(&self, other: &$lhs) -> bool { <OsStr as PartialEq>::eq(self, other) }
            }

            #[stable(feature = "cmp_os_str", since = "1.8.0")]
            impl<'a, 'b> PartialOrd<$rhs> for $lhs {
                #[inline]
                fn partial_cmp(&self, other: &$rhs) -> Option<cmp::Ordering> {
                    <OsStr as PartialOrd>::partial_cmp(self, other)
                }
            }

            #[stable(feature = "cmp_os_str", since = "1.8.0")]
            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);

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Hash for OsStr {
        #[inline]
        fn hash<H: Hasher>(&self, state: &mut H) {
            self.bytes().hash(state)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    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)
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl Borrow<OsStr> for OsString {
        fn borrow(&self) -> &OsStr { &self[..] }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl ToOwned for OsStr {
        type Owned = OsString;
        fn to_owned(&self) -> OsString {
            self.to_os_string()
        }
        fn clone_into(&self, target: &mut OsString) {
            target.clear();
            target.push(self);
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl AsRef<OsStr> for OsStr {
        fn as_ref(&self) -> &OsStr {
            self
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl AsRef<OsStr> for OsString {
        fn as_ref(&self) -> &OsStr {
            self
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl AsRef<OsStr> for str {
        fn as_ref(&self) -> &OsStr {
            OsStr::from_inner(Slice::from_str(self))
        }
    }

    #[stable(feature = "rust1", since = "1.0.0")]
    impl AsRef<OsStr> for String {
        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 {
        fn as_inner(&self) -> &Slice {
            &self.inner
        }
    }

    #[cfg(test)]
    mod tests {
        use super::*;
        use sys_common::{AsInner, IntoInner};

        use rc::Rc;
        use sync::Arc;

        #[test]
        fn test_os_string_with_capacity() {
            let os_string = OsString::with_capacity(0);
            assert_eq!(0, os_string.inner.into_inner().capacity());

            let os_string = OsString::with_capacity(10);
            assert_eq!(10, os_string.inner.into_inner().capacity());

            let mut os_string = OsString::with_capacity(0);
            os_string.push("abc");
            assert!(os_string.inner.into_inner().capacity() >= 3);
        }

        #[test]
        fn test_os_string_clear() {
            let mut os_string = OsString::from("abc");
            assert_eq!(3, os_string.inner.as_inner().len());

            os_string.clear();
            assert_eq!(&os_string, "");
            assert_eq!(0, os_string.inner.as_inner().len());
        }

        #[test]
        fn test_os_string_capacity() {
            let os_string = OsString::with_capacity(0);
            assert_eq!(0, os_string.capacity());

            let os_string = OsString::with_capacity(10);
            assert_eq!(10, os_string.capacity());

            let mut os_string = OsString::with_capacity(0);
            os_string.push("abc");
            assert!(os_string.capacity() >= 3);
        }

        #[test]
        fn test_os_string_reserve() {
            let mut os_string = OsString::new();
            assert_eq!(os_string.capacity(), 0);

            os_string.reserve(2);
            assert!(os_string.capacity() >= 2);

            for _ in 0..16 {
                os_string.push("a");
            }

            assert!(os_string.capacity() >= 16);
            os_string.reserve(16);
            assert!(os_string.capacity() >= 32);

            os_string.push("a");

            os_string.reserve(16);
            assert!(os_string.capacity() >= 33)
        }

        #[test]
        fn test_os_string_reserve_exact() {
            let mut os_string = OsString::new();
            assert_eq!(os_string.capacity(), 0);

            os_string.reserve_exact(2);
            assert!(os_string.capacity() >= 2);

            for _ in 0..16 {
                os_string.push("a");
            }

            assert!(os_string.capacity() >= 16);
            os_string.reserve_exact(16);
            assert!(os_string.capacity() >= 32);

            os_string.push("a");

            os_string.reserve_exact(16);
            assert!(os_string.capacity() >= 33)
        }

        #[test]
        fn test_os_string_default() {
            let os_string: OsString = Default::default();
            assert_eq!("", &os_string);
        }

        #[test]
        fn test_os_str_is_empty() {
            let mut os_string = OsString::new();
            assert!(os_string.is_empty());

            os_string.push("abc");
            assert!(!os_string.is_empty());

            os_string.clear();
            assert!(os_string.is_empty());
        }

        #[test]
        fn test_os_str_len() {
            let mut os_string = OsString::new();
            assert_eq!(0, os_string.len());

            os_string.push("abc");
            assert_eq!(3, os_string.len());

            os_string.clear();
            assert_eq!(0, os_string.len());
        }

        #[test]
        fn test_os_str_default() {
            let os_str: &OsStr = Default::default();
            assert_eq!("", os_str);
        }

        #[test]
        fn into_boxed() {
            let orig = "Hello, world!";
            let os_str = OsStr::new(orig);
            let boxed: Box<OsStr> = Box::from(os_str);
            let os_string = os_str.to_owned().into_boxed_os_str().into_os_string();
            assert_eq!(os_str, &*boxed);
            assert_eq!(&*boxed, &*os_string);
            assert_eq!(&*os_string, os_str);
        }

        #[test]
        fn boxed_default() {
            let boxed = <Box<OsStr>>::default();
            assert!(boxed.is_empty());
        }

        #[test]
        fn test_os_str_clone_into() {
            let mut os_string = OsString::with_capacity(123);
            os_string.push("hello");
            let os_str = OsStr::new("bonjour");
            os_str.clone_into(&mut os_string);
            assert_eq!(os_str, os_string);
            assert!(os_string.capacity() >= 123);
        }

        #[test]
        fn into_rc() {
            let orig = "Hello, world!";
            let os_str = OsStr::new(orig);
            let rc: Rc<OsStr> = Rc::from(os_str);
            let arc: Arc<OsStr> = Arc::from(os_str);

            assert_eq!(&*rc, os_str);
            assert_eq!(&*arc, os_str);

            let rc2: Rc<OsStr> = Rc::from(os_str.to_owned());
            let arc2: Arc<OsStr> = Arc::from(os_str.to_owned());

            assert_eq!(&*rc2, os_str);
            assert_eq!(&*arc2, os_str);
        }
    }

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Search multiple things at once by splitting your query with comma (e.g. `str,u8` or `String,struct:Vec,test`)