Make various XMPPConnection setter accept nil

src/XMPPConnection.m

@@ -163,6 +163,8 @@
 - (void)setUsername: (OFString*)username_
 {
 	OFString *old = username;
+
+	if (username_ != nil) {
 		char *node;
 		Stringprep_rc rc;
 
@@ -179,6 +181,8 @@
 		} @finally {
 			free(node);
 		}
+	} else
+		username = nil;
 
 	[old release];
 }
@@ -191,6 +195,8 @@
 - (void)setResource: (OFString*)resource_
 {
 	OFString *old = resource;
+
+	if (resource_ != nil) {
 		char *res;
 		Stringprep_rc rc;
 
@@ -207,6 +213,8 @@
 		} @finally {
 			free(res);
 		}
+	} else
+		resource = nil;
 
 	[old release];
 }
@@ -219,7 +227,12 @@
 - (void)setServer: (OFString*)server_
 {
 	OFString *old = server;
+
+	if (server_ != nil)
 		server = [self XMPP_IDNAToASCII: server_];
+	else
+		server = nil;
+
 	[old release];
 }
 
@@ -232,6 +245,8 @@
 {
 	OFString *oldDomain = domain;
 	OFString *oldDomainToASCII = domainToASCII;
+
+	if (domain_ != nil) {
 		char *srv;
 		Stringprep_rc rc;
 
@@ -248,9 +263,14 @@
 		} @finally {
 			free(srv);
 		}
-	[oldDomain release];
 
 		domainToASCII = [self XMPP_IDNAToASCII: domain];
+	} else {
+		domain = nil;
+		domainToASCII = nil;
+	}
+
+	[oldDomain release];
 	[oldDomainToASCII release];
 }
 
@@ -262,6 +282,8 @@
 - (void)setPassword: (OFString*)password_
 {
 	OFString *old = password;
+
+	if (password_ != nil) {
 		char *pass;
 		Stringprep_rc rc;
 
@@ -278,6 +300,8 @@
 		} @finally {
 			free(pass);
 		}
+	} else
+		password = nil;
 
 	[old release];
 }