src/vendor/fuchsia-zircon/src/eventpair.rs

   1 // Copyright 2016 The Fuchsia Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 //! Type-safe bindings for Zircon event pairs.
   6
   7 use {AsHandleRef, Cookied, HandleBased, Handle, HandleRef, Peered, Status};
   8 use {sys, into_result};
   9
  10 /// An object representing a Zircon
  11 /// [event pair](https://fuchsia.googlesource.com/zircon/+/master/docs/concepts.md#Other-IPC_Events_Event-Pairs_and-User-Signals).
  12 ///
  13 /// As essentially a subtype of `Handle`, it can be freely interconverted.
  14 #[derive(Debug, Eq, PartialEq)]
  15 pub struct EventPair(Handle);
  16 impl_handle_based!(EventPair);
  17 impl Peered for EventPair {}
  18 impl Cookied for EventPair {}
  19
  20 impl EventPair {
  21     /// Create an event pair, a pair of objects which can signal each other. Wraps the
  22     /// [zx_eventpair_create](https://fuchsia.googlesource.com/zircon/+/master/docs/syscalls/eventpair_create.md)
  23     /// syscall.
  24     pub fn create(options: EventPairOpts) -> Result<(EventPair, EventPair), Status> {
  25         let mut out0 = 0;
  26         let mut out1 = 0;
  27         let status = unsafe { sys::zx_eventpair_create(options as u32, &mut out0, &mut out1) };
  28         into_result(status, ||
  29             (Self::from(Handle(out0)),
  30                 Self::from(Handle(out1))))
  31     }
  32 }
  33
  34 /// Options for creating an event pair.
  35 #[repr(u32)]
  36 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
  37 pub enum EventPairOpts {
  38     /// Default options.
  39     Default = 0,
  40 }
  41
  42 impl Default for EventPairOpts {
  43     fn default() -> Self {
  44         EventPairOpts::Default
  45     }
  46 }
  47
  48 #[cfg(test)]
  49 mod tests {
  50     use super::*;
  51     use {Duration, ZX_SIGNAL_LAST_HANDLE, ZX_SIGNAL_NONE, ZX_USER_SIGNAL_0};
  52     use deadline_after;
  53
  54     #[test]
  55     fn wait_and_signal_peer() {
  56         let (p1, p2) = EventPair::create(EventPairOpts::Default).unwrap();
  57         let eighty_ms: Duration = 80_000_000;
  58
  59         // Waiting on one without setting any signal should time out.
  60         assert_eq!(p2.wait_handle(ZX_USER_SIGNAL_0, deadline_after(eighty_ms)), Err(Status::ErrTimedOut));
  61
  62         // If we set a signal, we should be able to wait for it.
  63         assert!(p1.signal_peer(ZX_SIGNAL_NONE, ZX_USER_SIGNAL_0).is_ok());
  64         assert_eq!(p2.wait_handle(ZX_USER_SIGNAL_0, deadline_after(eighty_ms)).unwrap(),
  65             ZX_USER_SIGNAL_0 | ZX_SIGNAL_LAST_HANDLE);
  66
  67         // Should still work, signals aren't automatically cleared.
  68         assert_eq!(p2.wait_handle(ZX_USER_SIGNAL_0, deadline_after(eighty_ms)).unwrap(),
  69             ZX_USER_SIGNAL_0 | ZX_SIGNAL_LAST_HANDLE);
  70
  71         // Now clear it, and waiting should time out again.
  72         assert!(p1.signal_peer(ZX_USER_SIGNAL_0, ZX_SIGNAL_NONE).is_ok());
  73         assert_eq!(p2.wait_handle(ZX_USER_SIGNAL_0, deadline_after(eighty_ms)), Err(Status::ErrTimedOut));
  74     }
  75 }