diff -r 49a284f61e8c -r bbadf84cfc2d dav/sync.c
--- a/dav/sync.c	Sun May 07 11:53:10 2023 +0200
+++ b/dav/sync.c	Sun May 21 11:52:06 2023 +0200
@@ -113,6 +113,69 @@
     }
 }
 
+
+
+
+static bool nulliter_valid(void const *d) {
+    return false;
+}
+
+static void * nulliter_current(void const *d) {
+    return NULL;
+}
+
+void * nulliter_current_impl(void const *d) {
+    return NULL;
+}
+
+void nulliter_next(void *d) {
+    // noop
+}
+
+bool nulliter_flag_removal(void *d) {
+    return false;
+}
+
+
+static CxIterator nullIterator(void) {
+    CxIterator iter;
+    memset(&iter, 0, sizeof(CxIterator));
+    iter.base.valid = nulliter_valid;
+    iter.base.current = nulliter_current;
+    iter.base.current_impl = nulliter_current_impl;
+    iter.base.next = nulliter_next;
+    iter.base.flag_removal = nulliter_flag_removal;
+    return iter;
+}
+
+static CxIterator mapIteratorValues(CxMap *map) {
+    return map ? cxMapIteratorValues(map) : nullIterator();
+}
+
+static CxIterator listIterator(CxList *list) {
+    return list ? cxListIterator(list) : nullIterator();
+}
+
+typedef void*(*clonefunc)(void *elm, void *userdata);
+
+static CxMap* mapClone(const CxAllocator *a, CxMap *map, clonefunc clone, void *userdata) {
+    CxMap *newmap = cxHashMapCreate(a, map->store_pointer ? CX_STORE_POINTERS : map->item_size, map->size + 4);
+    
+    CxIterator i = cxMapIterator(map);
+    if(clone) {
+        cx_foreach(CxMapEntry*, entry, i) {
+            void *newdata = clone(entry->value, userdata);
+            cxMapPut(newmap, *entry->key, newdata);
+        }
+    } else {
+        cx_foreach(CxMapEntry*, entry, i) {
+            cxMapPut(newmap, *entry->key, entry->value);
+        }
+    }
+    
+    return newmap;
+}
+
 int dav_sync_main(int argc, char **argv);
 
 #ifdef _WIN32
@@ -674,7 +737,7 @@
     CxMap  *lres_removed = cxHashMapCreate(cxDefaultAllocator, CX_STORE_POINTERS, 16); // type: LocalResource*
     
     //UcxMap *svrres = ucx_map_new(db->resources->count);
-    CxMap *dbres = NULL; // TODO: ucx_map_clone(db->resources, NULL, NULL);
+    CxMap *dbres = mapClone(cxDefaultAllocator, db->resources, NULL, NULL);
     
     CxList *stack = cxLinkedListCreateSimple(CX_STORE_POINTERS);
     cxListInsert(stack, 0, ls->children);
@@ -764,7 +827,7 @@
     // find deleted resources
     // svrres currently contains all resources from the server
     // and will replace the current db->resources map later
-    CxIterator i = cxMapIteratorValues(dbres);
+    CxIterator i = mapIteratorValues(dbres);
     cx_foreach(LocalResource *, local, i) {
         if (res_matches_dir_filter(dir, local->path)) {
             continue;