dav: Move displayname to common properties

crates/caldav/src/principal/mod.rs

@@ -56,12 +56,6 @@ impl Resource for PrincipalResource {
                     PrincipalPropName::CalendarUserType => {
                         PrincipalProp::CalendarUserType(self.principal.principal_type.to_owned())
                     }
-                    PrincipalPropName::Displayname => PrincipalProp::Displayname(
-                        self.principal
-                            .displayname
-                            .to_owned()
-                            .unwrap_or(self.principal.id.to_owned()),
-                    ),
                     PrincipalPropName::PrincipalUrl => {
                         PrincipalProp::PrincipalUrl(principal_url.into())
                     }
@@ -77,6 +71,15 @@ impl Resource for PrincipalResource {
         })
     }
 
+    fn get_displayname(&self) -> Option<&str> {
+        Some(
+            self.principal
+                .displayname
+                .as_ref()
+                .unwrap_or(&self.principal.id),
+        )
+    }
+
     fn get_owner(&self) -> Option<&str> {
         Some(&self.principal.id)
     }

crates/caldav/src/principal/prop.rs

@@ -5,9 +5,6 @@ use rustical_xml::{EnumVariants, PropName, XmlDeserialize, XmlSerialize};
 #[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone, EnumVariants, PropName)]
 #[xml(unit_variants_ident = "PrincipalPropName")]
 pub enum PrincipalProp {
-    #[xml(ns = "rustical_dav::namespace::NS_DAV")]
-    Displayname(String),
-
     // Scheduling Extensions to CalDAV (RFC 6638)
     #[xml(ns = "rustical_dav::namespace::NS_CALDAV", skip_deserializing)]
     CalendarUserType(PrincipalType),