simplify home_dir by removing unnecessary getpwuid_r wrapper

src/libstd/sys/unix/os.rs

@@ -483,30 +483,21 @@ pub fn home_dir() -> Option<PathBuf> {
                   target_os = "nacl",
                   target_os = "emscripten")))]
     unsafe fn fallback() -> Option<OsString> {
-        unsafe fn getpwduid_r(me: libc::uid_t, passwd: &mut libc::passwd,
-                              buf: &mut Vec<c_char>) -> Option<()> {
-            let mut result = ptr::null_mut();
-            match libc::getpwuid_r(me, passwd, buf.as_mut_ptr(),
-                                   buf.capacity(),
-                                   &mut result) {
-                0 if !result.is_null() => Some(()),
-                _ => None
-            }
-        }
-
         let amt = match libc::sysconf(libc::_SC_GETPW_R_SIZE_MAX) {
             n if n < 0 => 512 as usize,
             n => n as usize,
         };
         let mut buf = Vec::with_capacity(amt);
         let mut passwd: libc::passwd = mem::zeroed();
-
+        let mut result = ptr::null_mut();
-        if getpwduid_r(libc::getuid(), &mut passwd, &mut buf).is_some() {
+        match libc::getpwuid_r(libc::getuid(), &mut passwd, buf.as_mut_ptr(),
-            let ptr = passwd.pw_dir as *const _;
+                               buf.capacity(), &mut result) {
-            let bytes = CStr::from_ptr(ptr).to_bytes().to_vec();
+            0 if !result.is_null() => {
-            Some(OsStringExt::from_vec(bytes))
+                let ptr = passwd.pw_dir as *const _;
-        } else {
+                let bytes = CStr::from_ptr(ptr).to_bytes().to_vec();
-            None
+                Some(OsStringExt::from_vec(bytes))
+            },
+            _ => None,
         }
     }
 }