Add get_marker method to dc_array_t

deltachat-ffi/src/dc_array.rs

@@ -39,6 +39,17 @@ impl dc_array_t {
         }
     }
 
+    pub(crate) fn get_marker(&self, index: usize) -> Option<&str> {
+        match self {
+            Self::MsgIds(_) => None,
+            Self::Chat(array) => None,
+            Self::Locations(array) => array
+                .get(index)
+                .and_then(|location| location.marker.as_deref()),
+            Self::Uint(_) => None,
+        }
+    }
+
     pub(crate) fn get_location(&self, index: usize) -> &Location {
         if let Self::Locations(array) = self {
             &array[index]

deltachat-ffi/src/lib.rs

@@ -2068,7 +2068,7 @@ pub unsafe extern "C" fn dc_array_get_marker(
         return std::ptr::null_mut(); // NULL explicitly defined as "no markers"
     }
 
-    if let Some(s) = &(*array).get_location(index).marker {
+    if let Some(s) = (*array).get_marker(index) {
         s.strdup()
     } else {
         std::ptr::null_mut()