Auto merge of #399 - fiveop:less_ffi_poll, r=posborne

Use libc in poll.rs

I'll add a change log commit, once this is reviewed.

CHANGELOG.md

@@ -23,6 +23,12 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   ([#407](https://github.com/nix-rust/nix/pull/407))
 - Added `CpuSet::unset` in `::nix::sched`.
   ([#402](https://github.com/nix-rust/nix/pull/402))
+- Added constructor method `new()` to `PollFd` in `::nix::poll`, in order to
+  allow creation of objects, after removing public access to members.
+  ([#399](https://github.com/nix-rust/nix/pull/399))
+- Added method `revents()` to `PollFd` in `::nix::poll`, in order to provide
+  read access to formerly public member `revents`.
+  ([#399](https://github.com/nix-rust/nix/pull/399))
 
 ### Changed
 - Replaced the reexported integer constants for signals by the enumeration
@@ -40,6 +46,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   ([#362](https://github.com/nix-rust/nix/pull/362))
 - Type alias `CpuMask` from `::nix::shed`.
   ([#402](https://github.com/nix-rust/nix/pull/402))
+- Removed public fields from `PollFd` in `::nix::poll`. (See also added method
+  `revents()`.
+  ([#399](https://github.com/nix-rust/nix/pull/399))
 
 ### Fixed
 - Fixed the build problem for NetBSD (Note, that we currently do not support

src/poll.rs

@@ -1,74 +1,48 @@
-use libc::c_int;
+use libc;
 use {Errno, Result};
 
-pub use self::ffi::PollFd;
-pub use self::ffi::consts::*;
-
-mod ffi {
-    use libc::c_int;
-    pub use self::consts::*;
-
-    #[derive(Clone, Copy, Debug)]
-    #[repr(C)]
-    pub struct PollFd {
-        pub fd: c_int,
-        pub events: EventFlags,
-        pub revents: EventFlags
-    }
-
-    #[cfg(target_os = "linux")]
-    pub mod consts {
-        use libc::{c_short, c_ulong};
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct PollFd {
+    pollfd: libc::pollfd,
+}
 
-        bitflags! {
-            flags EventFlags: c_short {
-                const POLLIN     = 0x001,
-                const POLLPRI    = 0x002,
-                const POLLOUT    = 0x004,
-                const POLLRDNORM = 0x040,
-                const POLLWRNORM = 0x100,
-                const POLLRDBAND = 0x080,
-                const POLLWRBAND = 0x200,
-                const POLLERR    = 0x008,
-                const POLLHUP    = 0x010,
-                const POLLNVAL   = 0x020,
-            }
+impl PollFd {
+    pub fn new(fd: libc::c_int, events: EventFlags, revents: EventFlags) -> PollFd {
+        PollFd {
+            pollfd: libc::pollfd {
+                fd: fd,
+                events: events.bits(),
+                revents: revents.bits(),
+            },
         }
-
-        pub type nfds_t = c_ulong;
     }
 
-    #[cfg(target_os = "macos")]
-    pub mod consts {
-        use libc::{c_short, c_uint};
-
-        bitflags! {
-            flags EventFlags: c_short {
-                const POLLIN     = 0x0001,
-                const POLLPRI    = 0x0002,
-                const POLLOUT    = 0x0004,
-                const POLLRDNORM = 0x0040,
-                const POLLWRNORM = 0x0004,
-                const POLLRDBAND = 0x0080,
-                const POLLWRBAND = 0x0100,
-                const POLLERR    = 0x0008,
-                const POLLHUP    = 0x0010,
-                const POLLNVAL   = 0x0020,
-            }
-        }
-
-        pub type nfds_t = c_uint;
+    pub fn revents(&self) -> Option<EventFlags> {
+        EventFlags::from_bits(self.pollfd.revents)
     }
+}
 
-    #[allow(improper_ctypes)]
-    extern {
-        pub fn poll(fds: *mut PollFd, nfds: nfds_t, timeout: c_int) -> c_int;
+libc_bitflags! {
+    flags EventFlags: libc::c_short {
+        POLLIN,
+        POLLPRI,
+        POLLOUT,
+        POLLRDNORM,
+        POLLWRNORM,
+        POLLRDBAND,
+        POLLWRBAND,
+        POLLERR,
+        POLLHUP,
+        POLLNVAL,
     }
 }
 
-pub fn poll(fds: &mut [PollFd], timeout: c_int) -> Result<c_int> {
+pub fn poll(fds: &mut [PollFd], timeout: libc::c_int) -> Result<libc::c_int> {
     let res = unsafe {
-        ffi::poll(fds.as_mut_ptr(), fds.len() as ffi::nfds_t, timeout)
+        libc::poll(fds.as_mut_ptr() as *mut libc::pollfd,
+                   fds.len() as libc::nfds_t,
+                   timeout)
     };
 
     Errno::result(res)

test/test_poll.rs

@@ -4,19 +4,15 @@ use nix::unistd::{write, pipe};
 #[test]
 fn test_poll() {
     let (r, w) = pipe().unwrap();
-    let mut fds = [PollFd {
-        fd: r,
-        events: POLLIN,
-        revents: EventFlags::empty()
-    }];
+    let mut fds = [PollFd::new(r, POLLIN, EventFlags::empty())];
 
     let nfds = poll(&mut fds, 100).unwrap();
     assert_eq!(nfds, 0);
-    assert!(!fds[0].revents.contains(POLLIN));
+    assert!(!fds[0].revents().unwrap().contains(POLLIN));
 
     write(w, b".").unwrap();
 
     let nfds = poll(&mut fds, 100).unwrap();
     assert_eq!(nfds, 1);
-    assert!(fds[0].revents.contains(POLLIN));
+    assert!(fds[0].revents().unwrap().contains(POLLIN));
 }