Add sys::select::FdSet and sys::select::select.

4 files changed, 129 insertions, 0 deletions

diff --git a/src/sys/mod.rs b/src/sys/mod.rs
index eda95972..3e4a0836 100644
--- a/src/sys/mod.rs
+++ b/src/sys/mod.rs
@@ -47,3 +47,5 @@ pub mod time;
               target_arch = "arm")),
           )]
 pub mod ptrace;
+
+pub mod select;
diff --git a/src/sys/select.rs b/src/sys/select.rs
new file mode 100644
index 00000000..1060d618
--- /dev/null
+++ b/src/sys/select.rs
@@ -0,0 +1,84 @@
+use std::ptr::null_mut;
+use std::os::unix::io::RawFd;
+use libc::c_int;
+use {Result, Error};
+use errno::Errno;
+use sys::time::TimeVal;
+
+pub const FD_SETSIZE: RawFd = 1024;
+
+#[cfg(any(target_os = "macos", target_os = "ios"))]
+#[repr(C)]
+pub struct FdSet {
+    bits: [i32; FD_SETSIZE as usize / 32]
+}
+
+#[cfg(any(target_os = "macos", target_os = "ios"))]
+const BITS: usize = 32;
+
+#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+#[repr(C)]
+pub struct FdSet {
+    bits: [u64; FD_SETSIZE as usize / 64]
+}
+
+#[cfg(not(any(target_os = "macos", target_os = "ios")))]
+const BITS: usize = 64;
+
+impl FdSet {
+    pub fn new() -> FdSet {
+        FdSet {
+            bits: [0; FD_SETSIZE as usize / BITS]
+        }
+    }
+
+    pub fn insert(&mut self, fd: RawFd) {
+        let fd = fd as usize;
+        self.bits[fd / BITS] |= 1 << (fd % BITS);
+    }
+
+    pub fn remove(&mut self, fd: RawFd) {
+        let fd = fd as usize;
+        self.bits[fd / BITS] &= !(1 << (fd % BITS));
+    }
+
+    pub fn contains(&mut self, fd: RawFd) -> bool {
+        let fd = fd as usize;
+        self.bits[fd / BITS] & (1 << (fd % BITS)) > 0
+    }
+}
+
+mod ffi {
+    use libc::c_int;
+    use sys::time::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;
+    }
+}
+
+pub fn select(nfds: c_int,
+              readfds: Option<&mut FdSet>,
+              writefds: Option<&mut FdSet>,
+              errorfds: Option<&mut FdSet>,
+              timeout: &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 as *mut TimeVal;
+
+    let res = unsafe {
+        ffi::select(nfds, readfds, writefds, errorfds, timeout)
+    };
+
+    if res == -1 {
+        Err(Error::Sys(Errno::last()))
+    } else {   
+        Ok(res)
+    } 
+}
diff --git a/test/sys/mod.rs b/test/sys/mod.rs
index 8a1f77fd..fbb4a6e0 100644
--- a/test/sys/mod.rs
+++ b/test/sys/mod.rs
@@ -3,3 +3,4 @@ mod test_termios;
 mod test_uio;
 mod test_ioctl;
 mod test_wait;
+mod test_select;
diff --git a/test/sys/test_select.rs b/test/sys/test_select.rs
new file mode 100644
index 00000000..c9331886
--- /dev/null
+++ b/test/sys/test_select.rs
@@ -0,0 +1,42 @@
+use nix::sys::select::{FdSet, FD_SETSIZE, select};
+use nix::sys::time::TimeVal;
+use nix::unistd::{read, write, pipe};
+
+#[test]
+fn test_fdset() {
+    let mut fd_set = FdSet::new();
+
+    for i in 0..FD_SETSIZE {
+        assert!(!fd_set.contains(i));
+    }
+
+    fd_set.insert(7);
+
+    assert!(fd_set.contains(7));
+
+    fd_set.remove(7);
+
+    for i in 0..FD_SETSIZE {
+        assert!(!fd_set.contains(i));
+    }
+}
+
+#[test]
+fn test_select() {
+    let (r1, w1) = pipe().unwrap();
+    write(w1, b"hi!").unwrap();
+    let (r2, w2) = pipe().unwrap();
+
+    let mut fd_set = FdSet::new();
+    fd_set.insert(r1);
+    fd_set.insert(r2);
+
+    let mut timeout = TimeVal::seconds(1);
+    assert_eq!(1, select(r2 + 1,
+                         Some(&mut fd_set),
+                         None,
+                         None,
+                         &mut timeout).unwrap());
+    assert!(fd_set.contains(r1));
+    assert!(!fd_set.contains(r2));
+}