Refactored zmq::stream_engine_t::handshake, extracted several sub-methods

src/stream_engine.hpp

@@ -93,12 +93,22 @@ class stream_engine_t : public io_object_t, public i_engine
     //  Function to handle network disconnections.
     void error (error_reason_t reason_);
 
-    //  Receives the greeting message from the peer.
-    int receive_greeting ();
-
     //  Detects the protocol used by the peer.
     bool handshake ();
 
+    //  Receive the greeting from the peer.
+    int receive_greeting ();
+    void receive_greeting_versioned ();
+
+    typedef bool (stream_engine_t::*handshake_fun_t) ();
+    static handshake_fun_t select_handshake_fun (bool unversioned,
+                                                 unsigned char revision);
+
+    bool handshake_v1_0_unversioned ();
+    bool handshake_v1_0 ();
+    bool handshake_v2_0 ();
+    bool handshake_v3_0 ();
+
     int routing_id_msg (msg_t *msg_);
     int process_routing_id_msg (msg_t *msg_);