Third Party authentication protocol.

remoting/protocol/authenticator.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_PROTOCOL_AUTHENTICATOR_H_
 #define REMOTING_PROTOCOL_AUTHENTICATOR_H_
 
 #include <string>
 
+#include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 
 namespace buzz {
 class XmlElement;
 }  // namespace buzz
 
 namespace remoting {
 namespace protocol {
 
 class ChannelAuthenticator;
@@ skipping 11 matching lines @@
 // and session-accept messages or in a session-info
 // message. Session-info messages are used only if authenticators need
 // to exchange more than one message.
 class Authenticator {
  public:
   // Allowed state transitions:
   // When ProcessMessage() is called:
   //    WAITING_MESSAGE -> MESSAGE_READY
   //    WAITING_MESSAGE -> ACCEPTED
   //    WAITING_MESSAGE -> REJECTED
+  //    WAITING_MESSAGE -> WAITING_EXTERNAL

[Wez, 2013/02/27 07:05:30]

I don't like "external" - can we call this WAITING_LOCAL, WAITING_ACTION,
WAITING_USER or something along those lines?  I realise we won't always actually
need an action from the user but this is where user-interaction fits in so I
think it'd be reasonable.

[rmsousa, 2013/03/05 03:30:24]

Done in another CL.

   // When GetNextMessage() is called:
   //    MESSAGE_READY -> WAITING_MESSAGE
   //    MESSAGE_READY -> ACCEPTED
+  // When PerformExternalAction() is called:
+  //    WAITING_EXTERNAL -> MESSAGE_READY
+  //    WAITING_EXTERNAL -> ACCEPTED
+  //    WAITING_EXTERNAL -> REJECTED
   enum State {
     // Waiting for the next message from the peer.
     WAITING_MESSAGE,
 
     // Next message is ready to be sent to the peer.
     MESSAGE_READY,
 
     // Session is authenticated successufully.
     ACCEPTED,
 
     // Session is rejected.
     REJECTED,
+
+    // Waiting for PerformExternalAction to be called, or its action to finish.
+    WAITING_EXTERNAL,
   };
 
   enum RejectionReason {
     INVALID_CREDENTIALS,
     PROTOCOL_ERROR,
   };
 
   // Returns true if |message| is an Authenticator message.
   static bool IsAuthenticatorMessage(const buzz::XmlElement* message);
 
@@ skipping 16 matching lines @@
 
   // Called in response to incoming message received from the peer.
   // Should only be called when in WAITING_MESSAGE state. Caller
   // retains ownership of |message|.
   virtual void ProcessMessage(const buzz::XmlElement* message) = 0;
 
   // Must be called when in MESSAGE_READY state. Returns next
   // authentication message that needs to be sent to the peer.
   virtual scoped_ptr<buzz::XmlElement> GetNextMessage() = 0;
 
+  // Must be called when in WAITING_EXTERNAL state. Performs the external action
+  // (e.g. user prompt, network request), and calls |resume_callback| when done.
+  virtual void PerformExternalAction(const base::Closure& resume_callback);

[Wez, 2013/02/27 07:05:30]

nit: We don't provide a no-message default impl for GetNextMessage, so I'm not
sure we need one here?

Rather than having a separate PerformExternalAction API, could we add a
completion callback to ProcessMessage(), and letting that return true if it
processed the message immediately, or false if the caller needs to wait for the
completion callback?  The caller really doesn't care that the Authenticator is
performing some other activity as part of the auth process.

[rmsousa, 2013/03/05 03:30:24]

Done in another CL.

+
   // Creates new authenticator for a channel. Can be called only in
   // the ACCEPTED state.
   virtual scoped_ptr<ChannelAuthenticator>
       CreateChannelAuthenticator() const = 0;
 };
 
 // Factory for Authenticator instances.
 class AuthenticatorFactory {
  public:
   AuthenticatorFactory() {}
@@ skipping 10 matching lines @@
   virtual scoped_ptr<Authenticator> CreateAuthenticator(
       const std::string& local_jid,
       const std::string& remote_jid,
       const buzz::XmlElement* first_message) = 0;
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_AUTHENTICATOR_H_