Make Message::header return an Option in its Result (#9)

* Distinguishing between (non-)empty Message::header returns

* Switch Message::header Ok result to use nicer match syntax

1 files changed, 5 insertions, 2 deletions

diff --git a/src/message.rs b/src/message.rs
index dbf7cf2..ef9079f 100644
--- a/src/message.rs
+++ b/src/message.rs
@@ -83,13 +83,16 @@ impl<'o, Owner: MessageOwner + 'o> Message<'o, Owner> {
         unsafe { ffi::notmuch_message_get_date(self.handle.ptr) }
     }
 
-    pub fn header(&self, name: &str) -> Result<&str> {
+    pub fn header(&self, name: &str) -> Result<Option<&str>> {
         let name = CString::new(name).unwrap();
         let ret = unsafe { ffi::notmuch_message_get_header(self.handle.ptr, name.as_ptr()) };
         if ret.is_null() {
             Err(Error::UnspecifiedError)
         } else {
-            Ok(ret.to_str().unwrap())
+            Ok(match ret.to_str().unwrap() {
+                "" => None,
+                ret => Some(ret)
+            })
         }
     }