do not execute root NULL check in the beginning of dd_cov_update_cove…

…rage

ext/datadog_cov/datadog_cov.c

@@ -118,11 +118,6 @@ static void dd_cov_update_coverage(rb_event_flag_t event, VALUE data, VALUE self
   struct dd_cov_data *dd_cov_data;
   TypedData_Get_Struct(data, struct dd_cov_data, &dd_cov_data_type, dd_cov_data);
 
-  if (dd_cov_data->root == NULL)
-  {
-    return;
-  }
-
   int captured_frames = rb_profile_frames(
       0 /* stack starting depth */,
       1, /* number of stack frames to return */
@@ -144,14 +139,14 @@ static void dd_cov_update_coverage(rb_event_flag_t event, VALUE data, VALUE self
 
   // skip if we cover the same file again
   uintptr_t current_filename_ptr = (uintptr_t)c_filename;
-  if (dd_cov_data->last_filename_ptr == (uintptr_t)current_filename_ptr)
+  if (dd_cov_data->last_filename_ptr == current_filename_ptr)
   {
     return;
   }
   dd_cov_data->last_filename_ptr = current_filename_ptr;
 
   // if given filename is not located under the root, we skip it
-  if (is_prefix(dd_cov_data->root, dd_cov_data->root_len, c_filename) == 0)
+  if (dd_cov_data->root_len == 0 || is_prefix(dd_cov_data->root, dd_cov_data->root_len, c_filename) == 0)
   {
     return;
   }