client: Remove Result from Mechanism::initial().

sasl/src/client/mechanisms/plain.rs

@@ -39,12 +39,12 @@ impl Mechanism for Plain {
         }
     }
 
-    fn initial(&mut self) -> Result<Vec<u8>, String> {
+    fn initial(&mut self) -> Vec<u8> {
         let mut auth = Vec::new();
         auth.push(0);
         auth.extend(self.username.bytes());
         auth.push(0);
         auth.extend(self.password.bytes());
-        Ok(auth)
+        auth
     }
 }

sasl/src/client/mechanisms/scram.rs

@@ -81,7 +81,7 @@ impl<S: ScramProvider> Mechanism for Scram<S> {
         }
     }
 
-    fn initial(&mut self) -> Result<Vec<u8>, String> {
+    fn initial(&mut self) -> Vec<u8> {
         let mut gs2_header = Vec::new();
         gs2_header.extend(self.channel_binding.header());
         let mut bare = Vec::new();
@@ -93,7 +93,7 @@ impl<S: ScramProvider> Mechanism for Scram<S> {
         data.extend(&gs2_header);
         data.extend(bare.clone());
         self.state = ScramState::SentInitialMessage { initial_message: bare, gs2_header: gs2_header };
-        Ok(data)
+        data
     }
 
     fn response(&mut self, challenge: &[u8]) -> Result<Vec<u8>, String> {
@@ -182,7 +182,7 @@ mod tests {
         let client_final = b"c=biws,r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,p=v0X8v3Bz2T0CJGbJQyF0X+HI4Ts=";
         let server_final = b"v=rmF9pqV8S7suAoZWja4dJRkFsKQ=";
         let mut mechanism = Scram::<Sha1>::new_with_nonce(username, password, client_nonce.to_owned());
-        let init = mechanism.initial().unwrap();
+        let init = mechanism.initial();
         assert_eq!( String::from_utf8(init.clone()).unwrap()
                   , String::from_utf8(client_init[..].to_owned()).unwrap() ); // depends on ordering…
         let resp = mechanism.response(&server_init[..]).unwrap();
@@ -201,7 +201,7 @@ mod tests {
         let client_final = b"c=biws,r=rOprNGfwEbeRWgbNEkqO%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0,p=dHzbZapWIk4jUhN+Ute9ytag9zjfMHgsqmmiz7AndVQ=";
         let server_final = b"v=6rriTRBi23WpRR/wtup+mMhUZUn/dB5nLTJRsjl95G4=";
         let mut mechanism = Scram::<Sha256>::new_with_nonce(username, password, client_nonce.to_owned());
-        let init = mechanism.initial().unwrap();
+        let init = mechanism.initial();
         assert_eq!( String::from_utf8(init.clone()).unwrap()
                   , String::from_utf8(client_init[..].to_owned()).unwrap() ); // depends on ordering…
         let resp = mechanism.response(&server_init[..]).unwrap();

sasl/src/client/mod.rs

@@ -9,8 +9,8 @@ pub trait Mechanism {
     fn from_credentials(credentials: Credentials) -> Result<Self, String> where Self: Sized;
 
     /// Provides initial payload of the SASL mechanism.
-    fn initial(&mut self) -> Result<Vec<u8>, String> {
-        Ok(Vec::new())
+    fn initial(&mut self) -> Vec<u8> {
+        Vec::new()
     }
 
     /// Creates a response to the SASL challenge.