Make ServerInfo::supports_feature return an Option

src/client/mod.rs

@@ -118,15 +118,15 @@ impl<S: Connecter + ClientStream + Clone> Client<S> {
 
         // Checks message encoding according to the server's capability
         // TODO : Add an encoding check.
-        if ! self.server_info.clone().unwrap().supports_feature(extension::EightBitMime).is_ok() {
-            if ! message.clone().to_string().is_ascii() {
+        if ! self.server_info.clone().unwrap().supports_feature(extension::EightBitMime).is_some() {
+            if ! message.clone().is_ascii() {
                 self.smtp_fail::<S, &str>("Server does not accepts UTF-8 strings");
             }
         }
 
         // Get maximum message size if defined
         let max_size = match self.server_info.clone().unwrap().supports_feature(extension::Size(0)) {
-            Ok(extension::Size(max)) => max,
+            Some(extension::Size(max)) => max,
             _ => -1
         };
 

src/client/server_info.rs

@@ -63,17 +63,17 @@ impl ServerInfo {
     }
 
     /// Checks if the server supports an ESMTP feature
-    pub fn supports_feature(&self, keyword: Extension) -> Result<Extension, ()> {
+    pub fn supports_feature(&self, keyword: Extension) -> Option<Extension> {
         match self.esmtp_features.clone() {
             Some(esmtp_features) => {
                 for feature in esmtp_features.iter() {
                     if keyword.same_extension_as(*feature) {
-                        return Ok(*feature);
+                        return Some(*feature);
                     }
                 }
-                Err({})
+                None
             },
-            None => Err({})
+            None => None
         }
     }
 }
@@ -118,18 +118,18 @@ mod test {
         assert_eq!(ServerInfo{
             name: String::from_str("name"),
             esmtp_features: Some(vec!(extension::EightBitMime))
-        }.supports_feature(extension::EightBitMime), Ok(extension::EightBitMime));
+        }.supports_feature(extension::EightBitMime), Some(extension::EightBitMime));
         assert_eq!(ServerInfo{
             name: String::from_str("name"),
             esmtp_features: Some(vec!(extension::Size(42), extension::EightBitMime))
-        }.supports_feature(extension::EightBitMime), Ok(extension::EightBitMime));
+        }.supports_feature(extension::EightBitMime), Some(extension::EightBitMime));
         assert_eq!(ServerInfo{
             name: String::from_str("name"),
             esmtp_features: Some(vec!(extension::Size(42), extension::EightBitMime))
-        }.supports_feature(extension::Size(0)), Ok(extension::Size(42)));
+        }.supports_feature(extension::Size(0)), Some(extension::Size(42)));
         assert!(ServerInfo{
             name: String::from_str("name"),
             esmtp_features: Some(vec!(extension::EightBitMime))
-        }.supports_feature(extension::Size(42)).is_err());
+        }.supports_feature(extension::Size(42)).is_none());
     }
 }