JAMES-1930 Refactor Auth plain parsing

protocols/imap/src/main/java/org/apache/james/imap/processor/AuthenticateProcessor.java

@@ -37,6 +37,8 @@
 import org.apache.james.imap.message.response.AuthenticateResponse;
 import org.apache.james.mailbox.MailboxManager;
 
+import com.google.common.base.Optional;
+
 /**
  * Processor which handles the AUTHENTICATE command. Only authtype of PLAIN is supported ATM.
  * 
@@ -101,16 +103,21 @@ public void onLine(ImapSession session, byte[] data) {
      * @param responder
      */
     protected void doPlainAuth(String initialClientResponse, ImapSession session, String tag, ImapCommand command, Responder responder) {
-        String pass = null;
-        String user = null;
+        AuthPlainAttempt authPlainAttempt = parseDelegationAttempt(initialClientResponse);
+        // Authenticate user
+        doAuth(authPlainAttempt.getAuthenticationId(), authPlainAttempt.getPassword(), session, tag, command, responder, HumanReadableText.AUTHENTICATION_FAILED);
+    }
+
+    private AuthPlainAttempt parseDelegationAttempt(String initialClientResponse) {
+        String token2;
         try {
 
             String userpass = new String(Base64.decodeBase64(initialClientResponse));
             StringTokenizer authTokenizer = new StringTokenizer(userpass, "\0");
-            String authorize_id = authTokenizer.nextToken();  // Authorization Identity
-            user = authTokenizer.nextToken();                 // Authentication Identity
+            String token1 = authTokenizer.nextToken();  // Authorization Identity
+            token2 = authTokenizer.nextToken();                 // Authentication Identity
             try {
-                pass = authTokenizer.nextToken();             // Password
+                return delegation(token1, token2, authTokenizer.nextToken());
             } catch (java.util.NoSuchElementException _) {
                 // If we got here, this is what happened.  RFC 2595
                 // says that "the client may leave the authorization
@@ -127,19 +134,17 @@ protected void doPlainAuth(String initialClientResponse, ImapSession session, St
                 // elements, leading to the exception we just
                 // caught.  So we need to move the user to the
                 // password, and the authorize_id to the user.
-                pass = user;
-                user = authorize_id;
-            }   
-
-            authTokenizer = null;
+                return noDelegation(token1, token2);
+            } finally {
+                authTokenizer = null;
+            }
         } catch (Exception e) {
             // Ignored - this exception in parsing will be dealt
             // with in the if clause below
+            return noDelegation(null, null);
         }
-        // Authenticate user
-        doAuth(user, pass, session, tag, command, responder, HumanReadableText.AUTHENTICATION_FAILED);
     }
-    
+
     /**
      * @see org.apache.james.imap.processor.CapabilityImplementingProcessor
      * #getImplementedCapabilities(org.apache.james.imap.api.process.ImapSession)
@@ -156,4 +161,40 @@ public List<String> getImplementedCapabilities(ImapSession session) {
         return Collections.unmodifiableList(caps);
     }
 
+    private static AuthPlainAttempt delegation(String authorizeId, String authenticationId, String password) {
+        return new AuthPlainAttempt(Optional.of(authorizeId), authenticationId, password);
+    }
+
+    private static AuthPlainAttempt noDelegation(String authenticationId, String password) {
+        return new AuthPlainAttempt(Optional.<String>absent(), authenticationId, password);
+    }
+
+    private static class AuthPlainAttempt {
+        private final Optional<String> authorizeId;
+        private final String authenticationId;
+        private final String password;
+
+        private AuthPlainAttempt(Optional<String> authorizeId, String authenticationId, String password) {
+            this.authorizeId = authorizeId;
+            this.authenticationId = authenticationId;
+            this.password = password;
+        }
+
+        public boolean isDelegation() {
+            return authorizeId.isPresent();
+        }
+
+        public Optional<String> getAuthorizeId() {
+            return authorizeId;
+        }
+
+        public String getAuthenticationId() {
+            return authenticationId;
+        }
+
+        public String getPassword() {
+            return password;
+        }
+    }
+
 }