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use io;
use libc::{self, c_int};
use mem;
use sync::atomic::{AtomicBool, Ordering};
use sys::fd::FileDesc;
use sys::{cvt, cvt_r};
pub struct AnonPipe(FileDesc);
pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
syscall! { fn pipe2(fds: *mut c_int, flags: c_int) -> c_int }
static INVALID: AtomicBool = AtomicBool::new(false);
let mut fds = [0; 2];
if cfg!(any(target_os = "dragonfly",
target_os = "freebsd",
target_os = "linux",
target_os = "netbsd",
target_os = "openbsd")) &&
!INVALID.load(Ordering::SeqCst)
{
match cvt(unsafe { pipe2(fds.as_mut_ptr(), libc::O_CLOEXEC) }) {
Ok(_) => {
return Ok((AnonPipe(FileDesc::new(fds[0])),
AnonPipe(FileDesc::new(fds[1]))));
}
Err(ref e) if e.raw_os_error() == Some(libc::ENOSYS) => {
INVALID.store(true, Ordering::SeqCst);
}
Err(e) => return Err(e),
}
}
cvt(unsafe { libc::pipe(fds.as_mut_ptr()) })?;
let fd0 = FileDesc::new(fds[0]);
let fd1 = FileDesc::new(fds[1]);
fd0.set_cloexec()?;
fd1.set_cloexec()?;
Ok((AnonPipe(fd0), AnonPipe(fd1)))
}
impl AnonPipe {
pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
self.0.read(buf)
}
pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
self.0.write(buf)
}
pub fn fd(&self) -> &FileDesc { &self.0 }
pub fn into_fd(self) -> FileDesc { self.0 }
}
pub fn read2(p1: AnonPipe,
v1: &mut Vec<u8>,
p2: AnonPipe,
v2: &mut Vec<u8>) -> io::Result<()> {
let p1 = p1.into_fd();
let p2 = p2.into_fd();
p1.set_nonblocking(true)?;
p2.set_nonblocking(true)?;
let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() };
fds[0].fd = p1.raw();
fds[0].events = libc::POLLIN;
fds[1].fd = p2.raw();
fds[1].events = libc::POLLIN;
loop {
cvt_r(|| unsafe { libc::poll(fds.as_mut_ptr(), 2, -1) })?;
if fds[0].revents != 0 && read(&p1, v1)? {
p2.set_nonblocking(false)?;
return p2.read_to_end(v2).map(|_| ());
}
if fds[1].revents != 0 && read(&p2, v2)? {
p1.set_nonblocking(false)?;
return p1.read_to_end(v1).map(|_| ());
}
}
fn read(fd: &FileDesc, dst: &mut Vec<u8>) -> Result<bool, io::Error> {
match fd.read_to_end(dst) {
Ok(_) => Ok(true),
Err(e) => {
if e.raw_os_error() == Some(libc::EWOULDBLOCK) ||
e.raw_os_error() == Some(libc::EAGAIN) {
Ok(false)
} else {
Err(e)
}
}
}
}
}