sip: try to resolve sips transport living scope

This patch tries to decrease some refcount on share_ptr<SipTransport>
to not lock them all the time.

Tuleap: #64
Change-Id: Ibbdf91bfd7e978fe2f04693130cd77d8937b8fab

src/sip/sipcall.cpp

@@ -183,7 +183,7 @@ void SIPCall::setContactHeader(pj_str_t *contact)
 }
 
 void
-SIPCall::setTransport(const std::shared_ptr<SipTransport>& t)
+SIPCall::setTransport(std::shared_ptr<SipTransport> t)
 {
     const auto list_id = reinterpret_cast<uintptr_t>(this);
     if (transport_)
@@ -195,18 +195,15 @@ SIPCall::setTransport(const std::shared_ptr<SipTransport>& t)
 
         // listen for transport destruction
         transport_->addStateListener(list_id,
-            [wthis_, t, list_id] (pjsip_transport_state state,
-                                  const pjsip_transport_state_info*)
-            {
+            [wthis_] (pjsip_transport_state state, const pjsip_transport_state_info*) {
                 if (auto this_ = wthis_.lock()) {
                     // end the call if the SIP transport is shut down
-                    if (not SipTransport::isAlive(t, state) and this_->getConnectionState() != ConnectionState::DISCONNECTED) {
+                    if (not SipTransport::isAlive(this_->transport_, state) and this_->getConnectionState() != ConnectionState::DISCONNECTED) {
                         RING_WARN("[call:%s] Ending call because underlying SIP transport was closed",
                                   this_->getCallId().c_str());
                         this_->onFailure(ECONNRESET);
                     }
-                } else // should not happen
-                    t->removeStateListener(list_id);
+                }
             });
     }
 }

src/sip/sipcall.h

@@ -128,10 +128,10 @@ class SIPCall : public Call
 
         void setContactHeader(pj_str_t *contact);
 
-        void setTransport(const std::shared_ptr<SipTransport>& t);
+        void setTransport(std::shared_ptr<SipTransport> t);
 
-        inline const std::shared_ptr<SipTransport>& getTransport() {
-            return transport_;
+        inline SipTransport* getTransport() {
+            return transport_.get();
         }
 
         void sendSIPInfo(const char *const body, const char *const subtype);