library/std/src/sys_common/os_str_bytes.rs

   1 //! The underlying OsString/OsStr implementation on Unix and many other
   2 //! systems: just a `Vec<u8>`/`[u8]`.
   3
   4 use crate::borrow::Cow;
   5 use crate::ffi::{OsStr, OsString};
   6 use crate::fmt;
   7 use crate::mem;
   8 use crate::rc::Rc;
   9 use crate::sealed::Sealed;
  10 use crate::str;
  11 use crate::sync::Arc;
  12 use crate::sys_common::bytestring::debug_fmt_bytestring;
  13 use crate::sys_common::{AsInner, FromInner, IntoInner};
  14
  15 use core::str::lossy::Utf8Lossy;
  16
  17 #[derive(Hash)]
  18 pub(crate) struct Buf {
  19     pub inner: Vec<u8>,
  20 }
  21
  22 // FIXME:
  23 // `Buf::as_slice` current implementation relies
  24 // on `Slice` being layout-compatible with `[u8]`.
  25 // When attribute privacy is implemented, `Slice` should be annotated as `#[repr(transparent)]`.
  26 // Anyway, `Slice` representation and layout are considered implementation detail, are
  27 // not documented and must not be relied upon.
  28 pub(crate) struct Slice {
  29     pub inner: [u8],
  30 }
  31
  32 impl fmt::Debug for Slice {
  33     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
  34         debug_fmt_bytestring(&self.inner, formatter)
  35     }
  36 }
  37
  38 impl fmt::Display for Slice {
  39     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
  40         fmt::Display::fmt(&Utf8Lossy::from_bytes(&self.inner), formatter)
  41     }
  42 }
  43
  44 impl fmt::Debug for Buf {
  45     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
  46         fmt::Debug::fmt(self.as_slice(), formatter)
  47     }
  48 }
  49
  50 impl fmt::Display for Buf {
  51     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
  52         fmt::Display::fmt(self.as_slice(), formatter)
  53     }
  54 }
  55
  56 impl Clone for Buf {
  57     #[inline]
  58     fn clone(&self) -> Self {
  59         Buf { inner: self.inner.clone() }
  60     }
  61
  62     #[inline]
  63     fn clone_from(&mut self, source: &Self) {
  64         self.inner.clone_from(&source.inner)
  65     }
  66 }
  67
  68 impl IntoInner<Vec<u8>> for Buf {
  69     fn into_inner(self) -> Vec<u8> {
  70         self.inner
  71     }
  72 }
  73
  74 impl AsInner<[u8]> for Buf {
  75     fn as_inner(&self) -> &[u8] {
  76         &self.inner
  77     }
  78 }
  79
  80 impl Buf {
  81     pub fn from_string(s: String) -> Buf {
  82         Buf { inner: s.into_bytes() }
  83     }
  84
  85     #[inline]
  86     pub fn with_capacity(capacity: usize) -> Buf {
  87         Buf { inner: Vec::with_capacity(capacity) }
  88     }
  89
  90     #[inline]
  91     pub fn clear(&mut self) {
  92         self.inner.clear()
  93     }
  94
  95     #[inline]
  96     pub fn capacity(&self) -> usize {
  97         self.inner.capacity()
  98     }
  99
 100     #[inline]
 101     pub fn reserve(&mut self, additional: usize) {
 102         self.inner.reserve(additional)
 103     }
 104
 105     #[inline]
 106     pub fn reserve_exact(&mut self, additional: usize) {
 107         self.inner.reserve_exact(additional)
 108     }
 109
 110     #[inline]
 111     pub fn shrink_to_fit(&mut self) {
 112         self.inner.shrink_to_fit()
 113     }
 114
 115     #[inline]
 116     pub fn shrink_to(&mut self, min_capacity: usize) {
 117         self.inner.shrink_to(min_capacity)
 118     }
 119
 120     #[inline]
 121     pub fn as_slice(&self) -> &Slice {
 122         // SAFETY: Slice just wraps [u8],
 123         // and &*self.inner is &[u8], therefore
 124         // transmuting &[u8] to &Slice is safe.
 125         unsafe { mem::transmute(&*self.inner) }
 126     }
 127
 128     #[inline]
 129     pub fn as_mut_slice(&mut self) -> &mut Slice {
 130         // SAFETY: Slice just wraps [u8],
 131         // and &mut *self.inner is &mut [u8], therefore
 132         // transmuting &mut [u8] to &mut Slice is safe.
 133         unsafe { mem::transmute(&mut *self.inner) }
 134     }
 135
 136     pub fn into_string(self) -> Result<String, Buf> {
 137         String::from_utf8(self.inner).map_err(|p| Buf { inner: p.into_bytes() })
 138     }
 139
 140     pub fn push_slice(&mut self, s: &Slice) {
 141         self.inner.extend_from_slice(&s.inner)
 142     }
 143
 144     #[inline]
 145     pub fn into_box(self) -> Box<Slice> {
 146         unsafe { mem::transmute(self.inner.into_boxed_slice()) }
 147     }
 148
 149     #[inline]
 150     pub fn from_box(boxed: Box<Slice>) -> Buf {
 151         let inner: Box<[u8]> = unsafe { mem::transmute(boxed) };
 152         Buf { inner: inner.into_vec() }
 153     }
 154
 155     #[inline]
 156     pub fn into_arc(&self) -> Arc<Slice> {
 157         self.as_slice().into_arc()
 158     }
 159
 160     #[inline]
 161     pub fn into_rc(&self) -> Rc<Slice> {
 162         self.as_slice().into_rc()
 163     }
 164 }
 165
 166 impl Slice {
 167     #[inline]
 168     fn from_u8_slice(s: &[u8]) -> &Slice {
 169         unsafe { mem::transmute(s) }
 170     }
 171
 172     #[inline]
 173     pub fn from_str(s: &str) -> &Slice {
 174         Slice::from_u8_slice(s.as_bytes())
 175     }
 176
 177     pub fn to_str(&self) -> Option<&str> {
 178         str::from_utf8(&self.inner).ok()
 179     }
 180
 181     pub fn to_string_lossy(&self) -> Cow<'_, str> {
 182         String::from_utf8_lossy(&self.inner)
 183     }
 184
 185     pub fn to_owned(&self) -> Buf {
 186         Buf { inner: self.inner.to_vec() }
 187     }
 188
 189     pub fn clone_into(&self, buf: &mut Buf) {
 190         self.inner.clone_into(&mut buf.inner)
 191     }
 192
 193     #[inline]
 194     pub fn into_box(&self) -> Box<Slice> {
 195         let boxed: Box<[u8]> = self.inner.into();
 196         unsafe { mem::transmute(boxed) }
 197     }
 198
 199     pub fn empty_box() -> Box<Slice> {
 200         let boxed: Box<[u8]> = Default::default();
 201         unsafe { mem::transmute(boxed) }
 202     }
 203
 204     #[inline]
 205     pub fn into_arc(&self) -> Arc<Slice> {
 206         let arc: Arc<[u8]> = Arc::from(&self.inner);
 207         unsafe { Arc::from_raw(Arc::into_raw(arc) as *const Slice) }
 208     }
 209
 210     #[inline]
 211     pub fn into_rc(&self) -> Rc<Slice> {
 212         let rc: Rc<[u8]> = Rc::from(&self.inner);
 213         unsafe { Rc::from_raw(Rc::into_raw(rc) as *const Slice) }
 214     }
 215
 216     #[inline]
 217     pub fn make_ascii_lowercase(&mut self) {
 218         self.inner.make_ascii_lowercase()
 219     }
 220
 221     #[inline]
 222     pub fn make_ascii_uppercase(&mut self) {
 223         self.inner.make_ascii_uppercase()
 224     }
 225
 226     #[inline]
 227     pub fn to_ascii_lowercase(&self) -> Buf {
 228         Buf { inner: self.inner.to_ascii_lowercase() }
 229     }
 230
 231     #[inline]
 232     pub fn to_ascii_uppercase(&self) -> Buf {
 233         Buf { inner: self.inner.to_ascii_uppercase() }
 234     }
 235
 236     #[inline]
 237     pub fn is_ascii(&self) -> bool {
 238         self.inner.is_ascii()
 239     }
 240
 241     #[inline]
 242     pub fn eq_ignore_ascii_case(&self, other: &Self) -> bool {
 243         self.inner.eq_ignore_ascii_case(&other.inner)
 244     }
 245 }
 246
 247 /// Platform-specific extensions to [`OsString`].
 248 ///
 249 /// This trait is sealed: it cannot be implemented outside the standard library.
 250 /// This is so that future additional methods are not breaking changes.
 251 #[stable(feature = "rust1", since = "1.0.0")]
 252 pub trait OsStringExt: Sealed {
 253     /// Creates an [`OsString`] from a byte vector.
 254     ///
 255     /// See the module documentation for an example.
 256     #[stable(feature = "rust1", since = "1.0.0")]
 257     fn from_vec(vec: Vec<u8>) -> Self;
 258
 259     /// Yields the underlying byte vector of this [`OsString`].
 260     ///
 261     /// See the module documentation for an example.
 262     #[stable(feature = "rust1", since = "1.0.0")]
 263     fn into_vec(self) -> Vec<u8>;
 264 }
 265
 266 #[stable(feature = "rust1", since = "1.0.0")]
 267 impl OsStringExt for OsString {
 268     fn from_vec(vec: Vec<u8>) -> OsString {
 269         FromInner::from_inner(Buf { inner: vec })
 270     }
 271     fn into_vec(self) -> Vec<u8> {
 272         self.into_inner().inner
 273     }
 274 }
 275
 276 /// Platform-specific extensions to [`OsStr`].
 277 ///
 278 /// This trait is sealed: it cannot be implemented outside the standard library.
 279 /// This is so that future additional methods are not breaking changes.
 280 #[stable(feature = "rust1", since = "1.0.0")]
 281 pub trait OsStrExt: Sealed {
 282     #[stable(feature = "rust1", since = "1.0.0")]
 283     /// Creates an [`OsStr`] from a byte slice.
 284     ///
 285     /// See the module documentation for an example.
 286     fn from_bytes(slice: &[u8]) -> &Self;
 287
 288     /// Gets the underlying byte view of the [`OsStr`] slice.
 289     ///
 290     /// See the module documentation for an example.
 291     #[stable(feature = "rust1", since = "1.0.0")]
 292     fn as_bytes(&self) -> &[u8];
 293 }
 294
 295 #[stable(feature = "rust1", since = "1.0.0")]
 296 impl OsStrExt for OsStr {
 297     #[inline]
 298     fn from_bytes(slice: &[u8]) -> &OsStr {
 299         unsafe { mem::transmute(slice) }
 300     }
 301     #[inline]
 302     fn as_bytes(&self) -> &[u8] {
 303         &self.as_inner().inner
 304     }
 305 }