// 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::ffi::{OsStr, OsString};
use crate::mem;
use crate::sealed::Sealed;
use crate::sys::os_str::Buf;
use crate::sys_common::{AsInner, FromInner, IntoInner};

// Note: this file is currently reused in other `std::os::{platform}::ffi` modules to reduce duplication.
// Keep this in mind when applying changes to this file that only apply to `unix`.

/// Platform-specific extensions to [`OsString`].
///
/// This trait is sealed: it cannot be implemented outside the standard library.
/// This is so that future additional methods are not breaking changes.
pub trait OsStringExt: Sealed {
    /// Creates an [`OsString`] from a byte vector.
    ///
    /// See the module documentation for an example.
    fn from_vec(vec: Vec<u8>) -> Self;

    /// Yields the underlying byte vector of this [`OsString`].
    ///
    /// See the module documentation for an example.
    fn into_vec(self) -> Vec<u8>;
}

impl OsStringExt for OsString {
    #[inline]
    fn from_vec(vec: Vec<u8>) -> OsString {
        FromInner::from_inner(Buf { inner: vec })
    }
    #[inline]
    fn into_vec(self) -> Vec<u8> {
        self.into_inner().inner
    }
}

/// Platform-specific extensions to [`OsStr`].
///
/// This trait is sealed: it cannot be implemented outside the standard library.
/// This is so that future additional methods are not breaking changes.
pub trait OsStrExt: Sealed {
    /// Creates an [`OsStr`] from a byte slice.
    ///
    /// See the module documentation for an example.
    fn from_bytes(slice: &[u8]) -> &Self;

    /// Gets the underlying byte view of the [`OsStr`] slice.
    ///
    /// See the module documentation for an example.
    fn as_bytes(&self) -> &[u8];
}

impl OsStrExt for OsStr {
    #[inline]
    fn from_bytes(slice: &[u8]) -> &OsStr {
        unsafe { mem::transmute(slice) }
    }
    #[inline]
    fn as_bytes(&self) -> &[u8] {
        &self.as_inner().inner
    }
}