identity: Remove direct usage of of useragent username

In preparation of introducing multiple identities we need to
remove usage of SIPUserAgent>>#username. The next step is to
actually be able to pass a different identity.

callagent/SIPIdentity.st

@@ -48,10 +48,10 @@ Object subclass: SIPIdentity [
     ]
 
     proxyUsername [
-        ^proxyUsername
+        ^proxyUsername ifNil: [username]
     ]
 
     proxyPassword [
-        ^proxyPassword
+        ^proxyPassword ifNil: [password]
     ]
 ]

callagent/session/SIPSessionBase.st

@@ -17,7 +17,7 @@
 "
 
 Object subclass: SIPSessionBase [
-    | rem ua initial_dialog dialog next_cseq |
+    | rem ua identity initial_dialog dialog next_cseq |
     <category: 'OsmoSIP-Callagent'>
     <comment: 'I am the base for sessions. I am a bit backward as the
 Dialog will create/hold the session but we start with the session here
@@ -29,6 +29,7 @@ a proper session.'>
         <category: 'creation'>
         ^ self new
             useragent: aUseragent;
+            identity: aUseragent mainIdentity;
             initialDialog: aDialog;
             yourself
     ]
@@ -37,7 +38,7 @@ a proper session.'>
         <category: 'creation'>
         initial_dialog := aDialog.
         initial_dialog contact: ('sip:<1s>@<2p>:<3p>'
-                expandMacrosWith: ua username with: ua transport address with: ua transport port).
+                expandMacrosWith: identity username with: ua transport address with: ua transport port).
     ]
 
     useragent: aUseragent [
@@ -45,6 +46,11 @@ a proper session.'>
         ua := aUseragent
     ]
 
+    identity: anIdentity [
+        <category: 'creation'>
+        identity := anIdentity
+    ]
+
     callId [
         <category: 'info'>
         ^ initial_dialog callId

callagent/transactions/SIPTransaction.st

@@ -18,7 +18,7 @@
 
 Object subclass: SIPTransaction [
     | sem useragent initial_dialog state timeout success failure notification
-      cseq branch retransmit_time fail_time removal
+      cseq branch retransmit_time fail_time removal identity
       authorization last_was_auth proxy_authorization last_was_proxy_auth |
 
     <category: 'OsmoSIP-Callagent'>
@@ -36,6 +36,7 @@ Object subclass: SIPTransaction [
         <category: 'creation'>
         ^ self new
             initialize;
+            identity: aUA mainIdentity;
             userAgent: aUA;
             initialDialog: aDialog;
             setupTransaction: aCseq;
@@ -73,6 +74,11 @@ Object subclass: SIPTransaction [
         useragent := aUA
     ]
 
+    identity: anIdentity [
+        <category: 'creation'>
+        identity := anIdentity
+    ]
+
     state [
         <category: 'state'>
         ^ state ifNil: [^ self class stateInitial]
@@ -180,13 +186,13 @@ Object subclass: SIPTransaction [
             ifFalse: [^self wrongAuth: aResp dialog: aDialog].
 
         authorization := SIPAuthorization new
-            username: useragent username;
+            username: identity username;
             realm: (auth at: 'realm');
             nonce: (auth at: 'nonce');
             uri: initial_dialog destinationAddress;
             yourself.
         authorization
-            calculateResponse: useragent password
+            calculateResponse: identity password
             operation: self class operationName.
 
         "Increase CSeq and generate a new branch"
@@ -221,7 +227,7 @@ Object subclass: SIPTransaction [
             ifFalse: [^self wrongAuth: aResp dialog: aDialog].
 
         proxy_authorization := SIPProxyAuthorization new
-            username: useragent proxyUsername;
+            username: identity proxyUsername;
             realm: (auth at: 'realm');
             nonce: (auth at: 'nonce');
             qop: (auth at: 'qop');
@@ -363,7 +369,7 @@ Object subclass: SIPTransaction [
         proxy_authorization ifNotNil: [
             proxy_authorization incrementClientNonce.
             proxy_authorization
-                calculateResponse: useragent proxyPassword
+                calculateResponse: identity proxyPassword
                 operation: self class operationName.
             aRequest addParameter: 'Proxy-Authorization' value: proxy_authorization].
     ]

callagent/useragent/SIPUserAgent.st

@@ -184,27 +184,12 @@ SIPUserAgentBase subclass: SIPUserAgent [
         mainIdentity username: aUser.
     ]
 
-    username [
-        <category: 'accessing'>
-        ^mainIdentity username
-    ]
-
     password: aPass [
         <category: 'accessing'>
         mainIdentity password: aPass
     ]
 
-    password [
-        <category: 'accessing'>
-        ^mainIdentity password
+    mainIdentity [
+        ^mainIdentity
     ]
-
-    proxyUsername [
-        ^mainIdentity proxyUsername ifNil: [mainIdentity username]
-    ]
-
-    proxyPassword [
-        ^mainIdentity proxyPassword ifNil: [mainIdentity password]
-    ]
-
 ]