|
| 1 | +use alloc::fmt; |
| 2 | +use core::marker::PhantomData; |
| 3 | +use std::{ffi, io}; |
| 4 | + |
| 5 | +pub type Offset = i64; |
| 6 | +pub type Raw = i32; |
| 7 | + |
| 8 | +const EBADF: i32 = 9; |
| 9 | + |
| 10 | +#[repr(transparent)] |
| 11 | +pub struct Owned { |
| 12 | + fd: Raw, |
| 13 | +} |
| 14 | + |
| 15 | +impl fmt::Debug for Owned { |
| 16 | + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 17 | + f.debug_tuple("crt_fd::Owned") |
| 18 | + .field(&self.as_raw()) |
| 19 | + .finish() |
| 20 | + } |
| 21 | +} |
| 22 | + |
| 23 | +#[derive(Copy, Clone)] |
| 24 | +#[repr(transparent)] |
| 25 | +pub struct Borrowed<'fd> { |
| 26 | + fd: Raw, |
| 27 | + _marker: PhantomData<&'fd Owned>, |
| 28 | +} |
| 29 | + |
| 30 | +impl PartialEq for Borrowed<'_> { |
| 31 | + fn eq(&self, other: &Self) -> bool { |
| 32 | + self.as_raw() == other.as_raw() |
| 33 | + } |
| 34 | +} |
| 35 | + |
| 36 | +impl Eq for Borrowed<'_> {} |
| 37 | + |
| 38 | +impl fmt::Debug for Borrowed<'_> { |
| 39 | + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 40 | + f.debug_tuple("crt_fd::Borrowed") |
| 41 | + .field(&self.as_raw()) |
| 42 | + .finish() |
| 43 | + } |
| 44 | +} |
| 45 | + |
| 46 | +impl Owned { |
| 47 | + /// Create a `crt_fd::Owned` from a raw file descriptor. |
| 48 | + /// |
| 49 | + /// # Safety |
| 50 | + /// |
| 51 | + /// `fd` must be a valid file descriptor for the embedding host. |
| 52 | + #[inline] |
| 53 | + pub const unsafe fn from_raw(fd: Raw) -> Self { |
| 54 | + Self { fd } |
| 55 | + } |
| 56 | + |
| 57 | + /// Create a `crt_fd::Owned` from a raw file descriptor. |
| 58 | + /// |
| 59 | + /// Returns an error if `fd` is -1. |
| 60 | + /// |
| 61 | + /// # Safety |
| 62 | + /// |
| 63 | + /// `fd` must be a valid file descriptor for the embedding host. |
| 64 | + #[inline] |
| 65 | + pub unsafe fn try_from_raw(fd: Raw) -> io::Result<Self> { |
| 66 | + if fd == -1 { |
| 67 | + Err(ebadf()) |
| 68 | + } else { |
| 69 | + Ok(unsafe { Self::from_raw(fd) }) |
| 70 | + } |
| 71 | + } |
| 72 | + |
| 73 | + #[inline] |
| 74 | + pub const fn borrow(&self) -> Borrowed<'_> { |
| 75 | + unsafe { Borrowed::borrow_raw(self.as_raw()) } |
| 76 | + } |
| 77 | + |
| 78 | + #[inline] |
| 79 | + pub const fn as_raw(&self) -> Raw { |
| 80 | + self.fd |
| 81 | + } |
| 82 | + |
| 83 | + #[inline] |
| 84 | + pub fn into_raw(self) -> Raw { |
| 85 | + let fd = self.fd; |
| 86 | + core::mem::forget(self); |
| 87 | + fd |
| 88 | + } |
| 89 | + |
| 90 | + pub fn leak<'fd>(self) -> Borrowed<'fd> { |
| 91 | + unsafe { Borrowed::borrow_raw(self.into_raw()) } |
| 92 | + } |
| 93 | +} |
| 94 | + |
| 95 | +impl Drop for Owned { |
| 96 | + fn drop(&mut self) {} |
| 97 | +} |
| 98 | + |
| 99 | +impl<'fd> Borrowed<'fd> { |
| 100 | + /// Create a `crt_fd::Borrowed` from a raw file descriptor. |
| 101 | + /// |
| 102 | + /// # Safety |
| 103 | + /// |
| 104 | + /// `fd` must be a valid file descriptor for the embedding host. |
| 105 | + #[inline] |
| 106 | + pub const unsafe fn borrow_raw(fd: Raw) -> Self { |
| 107 | + Self { |
| 108 | + fd, |
| 109 | + _marker: PhantomData, |
| 110 | + } |
| 111 | + } |
| 112 | + |
| 113 | + /// Create a `crt_fd::Borrowed` from a raw file descriptor. |
| 114 | + /// |
| 115 | + /// Returns an error if `fd` is -1. |
| 116 | + /// |
| 117 | + /// # Safety |
| 118 | + /// |
| 119 | + /// `fd` must be a valid file descriptor for the embedding host. |
| 120 | + #[inline] |
| 121 | + pub unsafe fn try_borrow_raw(fd: Raw) -> io::Result<Self> { |
| 122 | + if fd == -1 { |
| 123 | + Err(ebadf()) |
| 124 | + } else { |
| 125 | + Ok(unsafe { Self::borrow_raw(fd) }) |
| 126 | + } |
| 127 | + } |
| 128 | + |
| 129 | + #[inline] |
| 130 | + pub const fn as_raw(self) -> Raw { |
| 131 | + self.fd |
| 132 | + } |
| 133 | +} |
| 134 | + |
| 135 | +#[inline] |
| 136 | +fn ebadf() -> io::Error { |
| 137 | + io::Error::from_raw_os_error(EBADF) |
| 138 | +} |
| 139 | + |
| 140 | +pub fn open(_path: &ffi::CStr, _flags: i32, _mode: i32) -> io::Result<Owned> { |
| 141 | + Err(unsupported()) |
| 142 | +} |
| 143 | + |
| 144 | +pub fn openat(_dir: Borrowed<'_>, _path: &ffi::CStr, _flags: i32, _mode: i32) -> io::Result<Owned> { |
| 145 | + Err(unsupported()) |
| 146 | +} |
| 147 | + |
| 148 | +pub fn fsync(_fd: Borrowed<'_>) -> io::Result<()> { |
| 149 | + Err(ebadf()) |
| 150 | +} |
| 151 | + |
| 152 | +pub fn close(_fd: Owned) -> io::Result<()> { |
| 153 | + Err(ebadf()) |
| 154 | +} |
| 155 | + |
| 156 | +pub fn ftruncate(_fd: Borrowed<'_>, _len: Offset) -> io::Result<()> { |
| 157 | + Err(ebadf()) |
| 158 | +} |
| 159 | + |
| 160 | +pub fn write(_fd: Borrowed<'_>, _buf: &[u8]) -> io::Result<usize> { |
| 161 | + Err(ebadf()) |
| 162 | +} |
| 163 | + |
| 164 | +pub fn read(_fd: Borrowed<'_>, _buf: &mut [u8]) -> io::Result<usize> { |
| 165 | + Err(ebadf()) |
| 166 | +} |
| 167 | + |
| 168 | +fn unsupported() -> io::Error { |
| 169 | + io::Error::new( |
| 170 | + io::ErrorKind::Unsupported, |
| 171 | + "host file descriptors are unsupported on this platform", |
| 172 | + ) |
| 173 | +} |
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