add support for dirent family

Cargo.toml

@@ -22,7 +22,7 @@ preadv_pwritev = []
 signalfd = []
 
 [dependencies]
-libc = { git = "https://github.com/rust-lang/libc" }
+libc = { git = "https://github.com/Mic92/libc" }
 bitflags = "0.7"
 cfg-if = "0.1.0"
 void = "1.0.2"

src/dirent.rs

@@ -0,0 +1,55 @@
+use {Result, Error, Errno, NixPath};
+use errno;
+use libc::{self, DIR, c_long};
+use std::os::unix::io::RawFd;
+
+pub struct Dir {
+    handle: *mut DIR,
+}
+
+impl Drop for Dir {
+    fn drop(&mut self) {
+        unsafe { libc::closedir(self.handle) };
+    }
+}
+
+pub fn fdopendir(fd: RawFd) -> Result<Dir> {
+    let dirp = unsafe { libc::fdopendir(fd) };
+    if dirp.is_null() {
+        Err(Error::last().into())
+    } else {
+        Ok(Dir { handle: dirp })
+    }
+}
+
+pub fn opendir<P: ?Sized + NixPath>(name: &P) -> Result<Dir> {
+    let dirp = try!(name.with_nix_path(|cstr| unsafe { libc::opendir(cstr.as_ptr()) }));
+    if dirp.is_null() {
+        Err(Error::last().into())
+    } else {
+        Ok(Dir { handle: dirp })
+    }
+}
+
+pub fn readdir<'a>(dir: &'a mut Dir) -> Result<Option<&'a libc::dirent>> {
+    let dirent = unsafe {
+        Errno::clear();
+        libc::readdir(dir.handle)
+    };
+    if dirent.is_null() {
+        match Errno::last() {
+            errno::UnknownErrno => Ok(None),
+            _ => Err(Error::last().into()),
+        }
+    } else {
+        Ok(Some(unsafe { &*dirent }))
+    }
+}
+
+pub fn seekdir<'a>(dir: &'a mut Dir, loc: c_long) {
+    unsafe { libc::seekdir(dir.handle, loc) };
+}
+
+pub fn telldir<'a>(dir: &'a mut Dir) -> c_long {
+    unsafe { libc::telldir(dir.handle) }
+}

src/lib.rs

@@ -34,6 +34,7 @@ pub mod libc {
 pub use libc::{c_int, c_void};
 pub use errno::Errno;
 
+pub mod dirent;
 pub mod errno;
 pub mod features;
 pub mod fcntl;

test/test.rs

@@ -8,6 +8,7 @@ extern crate tempfile;
 extern crate nix_test as nixtest;
 
 mod sys;
+mod test_dirent;
 mod test_fcntl;
 mod test_net;
 mod test_nix_path;

test/test_dirent.rs

@@ -0,0 +1,37 @@
+
+mod test_dirent {
+    use nix::dirent::{opendir, fdopendir, readdir, seekdir, telldir, Dir};
+    use std::fs::File;
+    use std::os::unix::io::IntoRawFd;
+    use std::path::Path;
+    use tempdir::TempDir;
+
+    fn test_readdir<OPEN>(open_fn: OPEN)
+        where OPEN: Fn(&Path) -> Dir
+    {
+        let tempdir = TempDir::new("nix-test_readdir")
+            .unwrap_or_else(|e| panic!("tempdir failed: {}", e));
+        let mut dir = open_fn(tempdir.path());
+        let entry1 = readdir(&mut dir).unwrap().unwrap().clone();
+        assert_eq!(entry1.d_name[0..2], ['.' as i8, '\0' as i8]);
+
+        let pos = telldir(&mut dir);
+        seekdir(&mut dir, pos); // no-op
+
+        let entry2 = readdir(&mut dir).unwrap().unwrap().clone();
+        assert_eq!(entry2.d_name[0..2], ['.' as i8, '.' as i8]);
+
+        assert!(readdir(&mut dir).unwrap().is_none());
+    }
+
+    #[test]
+    fn test_opendir() {
+        test_readdir(|path| opendir(path).unwrap());
+    }
+
+    #[test]
+    fn test_fdopendir() {
+        test_readdir(|path| fdopendir(File::open(path).unwrap().into_raw_fd()).unwrap());
+    }
+
+}