pbs-tools/src/io.rs

   1 //! I/O utilities.
   2
   3 use anyhow::Error;
   4
   5 use proxmox::tools::fd::Fd;
   6
   7 /// The `BufferedRead` trait provides a single function
   8 /// `buffered_read`. It returns a reference to an internal buffer. The
   9 /// purpose of this traid is to avoid unnecessary data copies.
  10 pub trait BufferedRead {
  11     /// This functions tries to fill the internal buffers, then
  12     /// returns a reference to the available data. It returns an empty
  13     /// buffer if `offset` points to the end of the file.
  14     fn buffered_read(&mut self, offset: u64) -> Result<&[u8], Error>;
  15 }
  16
  17 /// safe wrapper for `nix::unistd::pipe2` defaulting to `O_CLOEXEC` and guarding the file
  18 /// descriptors.
  19 pub fn pipe() -> Result<(Fd, Fd), Error> {
  20     let (pin, pout) = nix::unistd::pipe2(nix::fcntl::OFlag::O_CLOEXEC)?;
  21     Ok((Fd(pin), Fd(pout)))
  22 }