is_empty for OsStr

src/libstd/ffi/os_str.rs

@@ -283,6 +283,12 @@ impl OsStr {
         self.to_bytes().and_then(|b| CString::new(b).ok())
     }
 
+    /// Checks if the string is empty.
+    #[unstable(feature = "os_extras", reason = "recently added", issue = "30259")]
+    pub fn is_empty(&self) -> bool {
+        self.inner.inner.is_empty()
+    }
+
     /// Gets the underlying byte representation.
     ///
     /// Note: it is *crucial* that this API is private, to avoid

src/libstd/lib.rs

@@ -226,6 +226,7 @@
 #![feature(const_fn)]
 #![feature(core_float)]
 #![feature(core_intrinsics)]
+#![feature(convert)]
 #![feature(decode_utf16)]
 #![feature(drop_in_place)]
 #![feature(dropck_parametricity)]
@@ -244,6 +245,7 @@
 #![feature(on_unimplemented)]
 #![feature(oom)]
 #![feature(optin_builtin_traits)]
+#![feature(os_extras)]
 #![feature(placement_in_syntax)]
 #![feature(rand)]
 #![feature(range_inclusive)]

src/libstd/path.rs

@@ -1146,6 +1146,7 @@ impl PathBuf {
     pub fn into_os_string(self) -> OsString {
         self.inner
     }
+
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1859,6 +1860,23 @@ impl Path {
     pub fn is_dir(&self) -> bool {
         fs::metadata(self).map(|m| m.is_dir()).unwrap_or(false)
     }
+
+    /// Checks if the path buffer is empty. On Windows, it will return false if the inner string is
+    /// invalid unicode. On Unix, this is a no-op.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("/tmp/foo.rs");
+    ///
+    /// assert!(!path.is_empty());
+    /// ```
+    #[unstable(feature = "os_extras", reason = "recently added", issue = "30259")]
+    pub fn is_empty(&self) -> bool {
+        self.inner.is_empty()
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -3188,6 +3206,17 @@ mod tests {
         }
     }
 
+    #[test]
+    pub fn is_empty() {
+        let path = Path::new("/tmp/foo.rs");
+        let mut path_buf = PathBuf::new();
+
+        assert!(!path.is_empty());
+        assert!(path_buf.is_empty());
+        path_buf.push("catsarecute");
+        assert!(!path_buf.is_empty());
+    }
+
     #[test]
     pub fn test_set_extension() {
         macro_rules! tfe(