pbs-tools/src/io.rs

   1 //! I/O utilities.
   2
   3 use proxmox_sys::fd::Fd;
   4
   5 /// The `BufferedRead` trait provides a single function
   6 /// `buffered_read`. It returns a reference to an internal buffer. The
   7 /// purpose of this traid is to avoid unnecessary data copies.
   8 pub trait BufferedRead {
   9     /// This functions tries to fill the internal buffers, then
  10     /// returns a reference to the available data. It returns an empty
  11     /// buffer if `offset` points to the end of the file.
  12     fn buffered_read(&mut self, offset: u64) -> Result<&[u8], anyhow::Error>;
  13 }
  14
  15 /// safe wrapper for `nix::unistd::pipe2` defaulting to `O_CLOEXEC` and guarding the file
  16 /// descriptors.
  17 pub fn pipe() -> Result<(Fd, Fd), nix::Error> {
  18     let (pin, pout) = nix::unistd::pipe2(nix::fcntl::OFlag::O_CLOEXEC)?;
  19     Ok((Fd(pin), Fd(pout)))
  20 }