1 use crate::fd::{AsFd, BorrowedFd};
2 use bitflags::bitflags;
3 
4 bitflags! {
5     /// `POLL*` flags for use with [`poll`].
6     ///
7     /// [`poll`]: crate::event::poll
8     #[repr(transparent)]
9     #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
10     pub struct PollFlags: u16 {
11         /// `POLLIN`
12         const IN = linux_raw_sys::general::POLLIN as u16;
13         /// `POLLPRI`
14         const PRI = linux_raw_sys::general::POLLPRI as u16;
15         /// `POLLOUT`
16         const OUT = linux_raw_sys::general::POLLOUT as u16;
17         /// `POLLRDNORM`
18         const RDNORM = linux_raw_sys::general::POLLRDNORM as u16;
19         /// `POLLWRNORM`
20         const WRNORM = linux_raw_sys::general::POLLWRNORM as u16;
21         /// `POLLRDBAND`
22         const RDBAND = linux_raw_sys::general::POLLRDBAND as u16;
23         /// `POLLWRBAND`
24         const WRBAND = linux_raw_sys::general::POLLWRBAND as u16;
25         /// `POLLERR`
26         const ERR = linux_raw_sys::general::POLLERR as u16;
27         /// `POLLHUP`
28         const HUP = linux_raw_sys::general::POLLHUP as u16;
29         /// `POLLNVAL`
30         const NVAL = linux_raw_sys::general::POLLNVAL as u16;
31         /// `POLLRDHUP`
32         const RDHUP = linux_raw_sys::general::POLLRDHUP as u16;
33 
34         /// <https://docs.rs/bitflags/*/bitflags/#externally-defined-flags>
35         const _ = !0;
36     }
37 }
38 
39 /// `struct pollfd`—File descriptor and flags for use with [`poll`].
40 ///
41 /// [`poll`]: crate::event::poll
42 #[doc(alias = "pollfd")]
43 #[repr(C)]
44 #[derive(Debug, Clone)]
45 pub struct PollFd<'fd> {
46     pub(crate) fd: BorrowedFd<'fd>,
47     pub(crate) events: u16,
48     pub(crate) revents: u16,
49 }
50 
51 impl<'fd> PollFd<'fd> {
52     /// Constructs a new `PollFd` holding `fd` and `events`.
53     #[inline]
new<Fd: AsFd>(fd: &'fd Fd, events: PollFlags) -> Self54     pub fn new<Fd: AsFd>(fd: &'fd Fd, events: PollFlags) -> Self {
55         Self::from_borrowed_fd(fd.as_fd(), events)
56     }
57 
58     /// Sets the contained file descriptor to `fd`.
59     #[inline]
set_fd<Fd: AsFd>(&mut self, fd: &'fd Fd)60     pub fn set_fd<Fd: AsFd>(&mut self, fd: &'fd Fd) {
61         self.fd = fd.as_fd();
62     }
63 
64     /// Clears the ready events.
65     #[inline]
clear_revents(&mut self)66     pub fn clear_revents(&mut self) {
67         self.revents = 0;
68     }
69 
70     /// Constructs a new `PollFd` holding `fd` and `events`.
71     ///
72     /// This is the same as `new`, but can be used to avoid borrowing the
73     /// `BorrowedFd`, which can be tricky in situations where the `BorrowedFd`
74     /// is a temporary.
75     #[inline]
from_borrowed_fd(fd: BorrowedFd<'fd>, events: PollFlags) -> Self76     pub fn from_borrowed_fd(fd: BorrowedFd<'fd>, events: PollFlags) -> Self {
77         Self {
78             fd,
79             events: events.bits(),
80             revents: 0,
81         }
82     }
83 
84     /// Returns the ready events.
85     #[inline]
revents(&self) -> PollFlags86     pub fn revents(&self) -> PollFlags {
87         // Use `.unwrap()` here because in theory we know we know all the bits
88         // the OS might set here, but OS's have added extensions in the past.
89         PollFlags::from_bits(self.revents).unwrap()
90     }
91 }
92 
93 impl<'fd> AsFd for PollFd<'fd> {
94     #[inline]
as_fd(&self) -> BorrowedFd<'_>95     fn as_fd(&self) -> BorrowedFd<'_> {
96         self.fd.as_fd()
97     }
98 }
99