tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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owned_str.rs (1925B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
      4 
      5 #![allow(unsafe_code)]
      6 
      7 //! A replacement for `Box<str>` that has a defined layout for FFI.
      8 
      9 use crate::owned_slice::OwnedSlice;
     10 use std::fmt;
     11 use std::ops::{Deref, DerefMut};
     12 
     13 /// A struct that basically replaces a Box<str>, but with a defined layout,
     14 /// suitable for FFI.
     15 #[repr(C)]
     16 #[derive(Clone, Default, Eq, MallocSizeOf, PartialEq, ToShmem)]
     17 pub struct OwnedStr(OwnedSlice<u8>);
     18 
     19 impl fmt::Debug for OwnedStr {
     20    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
     21        self.deref().fmt(formatter)
     22    }
     23 }
     24 
     25 impl Deref for OwnedStr {
     26    type Target = str;
     27 
     28    #[inline(always)]
     29    fn deref(&self) -> &Self::Target {
     30        unsafe { std::str::from_utf8_unchecked(&*self.0) }
     31    }
     32 }
     33 
     34 impl DerefMut for OwnedStr {
     35    #[inline(always)]
     36    fn deref_mut(&mut self) -> &mut Self::Target {
     37        unsafe { std::str::from_utf8_unchecked_mut(&mut *self.0) }
     38    }
     39 }
     40 
     41 impl OwnedStr {
     42    /// Convert the OwnedStr into a boxed str.
     43    #[inline]
     44    pub fn into_box(self) -> Box<str> {
     45        self.into_string().into_boxed_str()
     46    }
     47 
     48    /// Convert the OwnedStr into a `String`.
     49    #[inline]
     50    pub fn into_string(self) -> String {
     51        unsafe { String::from_utf8_unchecked(self.0.into_vec()) }
     52    }
     53 }
     54 
     55 impl From<OwnedStr> for String {
     56    #[inline]
     57    fn from(b: OwnedStr) -> Self {
     58        b.into_string()
     59    }
     60 }
     61 
     62 impl From<OwnedStr> for Box<str> {
     63    #[inline]
     64    fn from(b: OwnedStr) -> Self {
     65        b.into_box()
     66    }
     67 }
     68 
     69 impl From<Box<str>> for OwnedStr {
     70    #[inline]
     71    fn from(b: Box<str>) -> Self {
     72        Self::from(b.into_string())
     73    }
     74 }
     75 
     76 impl From<String> for OwnedStr {
     77    #[inline]
     78    fn from(s: String) -> Self {
     79        OwnedStr(s.into_bytes().into())
     80    }
     81 }