src/tools.rs

   1 //! Various utilities.
   2 //!
   3 //! Note that this should stay small, otherwise we should introduce a dependency on our `proxmox`
   4 //! crate as that's where we have all this stuff usually...
   5
   6 use std::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
   7
   8 pub use io_uring::iovec::{IoVec, IoVecMut};
   9
  10 /// Guard a raw file descriptor with a drop handler. This is mostly useful when access to an owned
  11 /// `RawFd` is required without the corresponding handler object (such as when only the file
  12 /// descriptor number is required in a closure which may be dropped instead of being executed).
  13 #[repr(transparent)]
  14 pub struct Fd(pub RawFd);
  15
  16 file_descriptor_impl!(Fd);
  17
  18 impl FromRawFd for Fd {
  19     unsafe fn from_raw_fd(fd: RawFd) -> Self {
  20         Self(fd)
  21     }
  22 }
  23
  24 /// Byte vector utilities.
  25 pub mod vec {
  26     /// Create an uninitialized byte vector of a specific size.
  27     ///
  28     /// This is just a shortcut for:
  29     /// ```no_run
  30     /// # let len = 64usize;
  31     /// let mut v = Vec::<u8>::with_capacity(len);
  32     /// unsafe {
  33     ///     v.set_len(len);
  34     /// }
  35     /// ```
  36     ///
  37     /// # Safety
  38     ///
  39     /// This is generally safe to call, but the contents of the vector are undefined.
  40     #[inline]
  41     pub unsafe fn uninitialized(len: usize) -> Vec<u8> {
  42         let mut out = Vec::with_capacity(len);
  43         out.set_len(len);
  44         out
  45     }
  46 }
  47
  48 pub trait FromFd {
  49     fn from_fd(fd: Fd) -> Self;
  50 }
  51
  52 impl<T: FromRawFd> FromFd for T {
  53     fn from_fd(fd: Fd) -> Self {
  54         unsafe { Self::from_raw_fd(fd.into_raw_fd()) }
  55     }
  56 }