fix sync token update (#1744)

Author: alainm23

core/Services/CalDAV/CalDAVClient.vala

@@ -370,16 +370,16 @@ public class Services.CalDAV.CalDAVClient : Services.CalDAV.WebDAVClient {
                             }
                         }
                     }
-
-                    var sync_token = propstat.get_first_prop_with_tagname ("sync-token");
-                    if (sync_token != null) {
-                        project.sync_id = sync_token.text_content;
-                        project.update_local ();
-                    }
                 }
             }
         }
 
+        var sync_token = multi_status.get_first_text_content_by_tag_name ("sync-token");
+        if (sync_token != null && sync_token != project.sync_id) {
+            project.sync_id = sync_token;
+            project.update_local ();
+        }
+
         project.loading = false;
     }
 

core/Services/CalDAV/WebDAVClient.vala

@@ -143,6 +143,17 @@ public class Services.CalDAV.WebDAVMultiStatus : Object {
         }
         return list;
     }
+
+    public string ? get_first_text_content_by_tag_name (string tag_name) {
+        foreach (var h in root.get_elements_by_tag_name (tag_name)) {
+            var text = h.text_content.strip ();
+            if (text != null && text.length > 0) {
+                return text;
+            }
+        }
+
+        return null;
+    }
 }