Replace ffi declarations for select

Author: Susurrus

src/sys/select.rs

@@ -1,70 +1,38 @@
-use std::ptr::null_mut;
+use std::mem;
 use std::os::unix::io::RawFd;
-use libc::{c_int, timeval};
+use std::ptr::null_mut;
+use libc::{self, c_int};
 use {Errno, Result};
 use sys::time::TimeVal;
 
-pub const FD_SETSIZE: RawFd = 1024;
-
-#[cfg(any(target_os = "macos", target_os = "ios"))]
-#[repr(C)]
-#[derive(Clone)]
-pub struct FdSet {
-    bits: [i32; FD_SETSIZE as usize / 32]
-}
-
-#[cfg(any(target_os = "macos", target_os = "ios"))]
-const BITS: usize = 32;
+pub use libc::FD_SETSIZE;
 
-#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+// FIXME: Change to repr(transparent) once it's stable
 #[repr(C)]
-#[derive(Clone)]
-pub struct FdSet {
-    bits: [u64; FD_SETSIZE as usize / 64]
-}
-
-#[cfg(not(any(target_os = "macos", target_os = "ios")))]
-const BITS: usize = 64;
+pub struct FdSet(libc::fd_set);
 
 impl FdSet {
     pub fn new() -> FdSet {
-        FdSet {
-            bits: [0; FD_SETSIZE as usize / BITS]
-        }
+        let mut fdset = unsafe { mem::uninitialized() };
+        unsafe { libc::FD_ZERO(&mut fdset) };
+        FdSet(fdset)
     }
 
     pub fn insert(&mut self, fd: RawFd) {
-        let fd = fd as usize;
-        self.bits[fd / BITS] |= 1 << (fd % BITS);
+        unsafe { libc::FD_SET(fd, &mut self.0) };
     }
 
     pub fn remove(&mut self, fd: RawFd) {
-        let fd = fd as usize;
-        self.bits[fd / BITS] &= !(1 << (fd % BITS));
+        unsafe { libc::FD_CLR(fd, &mut self.0) };
     }
 
-    pub fn contains(&self, fd: RawFd) -> bool {
-        let fd = fd as usize;
-        self.bits[fd / BITS] & (1 << (fd % BITS)) > 0
+    // FIXME: Change to take `&self` once https://github.com/rust-lang/libc/pull/718 lands
+    pub fn contains(&mut self, fd: RawFd) -> bool {
+        unsafe { libc::FD_ISSET(fd, &mut self.0) }
     }
 
     pub fn clear(&mut self) {
-        for bits in &mut self.bits {
-            *bits = 0
-        }
-    }
-}
-
-mod ffi {
-    use libc::{c_int, timeval};
-    use super::FdSet;
-
-    extern {
-        pub fn select(nfds: c_int,
-                      readfds: *mut FdSet,
-                      writefds: *mut FdSet,
-                      errorfds: *mut FdSet,
-                      timeout: *mut timeval) -> c_int;
+        unsafe { libc::FD_ZERO(&mut self.0) };
     }
 }
 
@@ -73,14 +41,14 @@ pub fn select(nfds: c_int,
               writefds: Option<&mut FdSet>,
               errorfds: Option<&mut FdSet>,
               timeout: Option<&mut TimeVal>) -> Result<c_int> {
-    let readfds = readfds.map(|set| set as *mut FdSet).unwrap_or(null_mut());
-    let writefds = writefds.map(|set| set as *mut FdSet).unwrap_or(null_mut());
-    let errorfds = errorfds.map(|set| set as *mut FdSet).unwrap_or(null_mut());
-    let timeout = timeout.map(|tv| tv as *mut TimeVal as *mut timeval)
+    let readfds = readfds.map(|set| set as *mut _ as *mut libc::fd_set).unwrap_or(null_mut());
+    let writefds = writefds.map(|set| set as *mut _ as *mut libc::fd_set).unwrap_or(null_mut());
+    let errorfds = errorfds.map(|set| set as *mut _ as *mut libc::fd_set).unwrap_or(null_mut());
+    let timeout = timeout.map(|tv| tv as *mut _ as *mut libc::timeval)
                          .unwrap_or(null_mut());
 
     let res = unsafe {
-        ffi::select(nfds, readfds, writefds, errorfds, timeout)
+        libc::select(nfds, readfds, writefds, errorfds, timeout)
     };
 
     Errno::result(res)

test/sys/test_select.rs

@@ -7,7 +7,7 @@ fn test_fdset() {
     let mut fd_set = FdSet::new();
 
     for i in 0..FD_SETSIZE {
-        assert!(!fd_set.contains(i));
+        assert!(!fd_set.contains(i as i32));
     }
 
     fd_set.insert(7);
@@ -17,17 +17,17 @@ fn test_fdset() {
     fd_set.remove(7);
 
     for i in 0..FD_SETSIZE {
-        assert!(!fd_set.contains(i));
+        assert!(!fd_set.contains(i as i32));
     }
 
     fd_set.insert(1);
-    fd_set.insert(FD_SETSIZE / 2);
-    fd_set.insert(FD_SETSIZE - 1);
+    fd_set.insert(FD_SETSIZE as i32 / 2);
+    fd_set.insert(FD_SETSIZE as i32 - 1);
 
     fd_set.clear();
 
     for i in 0..FD_SETSIZE {
-        assert!(!fd_set.contains(i));
+        assert!(!fd_set.contains(i as i32));
     }
 }