extract common behavior

src/providers/base_provider.cpp

@@ -146,6 +146,27 @@ auto base_provider::get_api_path_from_source(const std::string &source_path,
   return api_error::item_not_found;
 }
 
+auto base_provider::get_file_size(const std::string &api_path,
+                                  std::uint64_t &file_size) const -> api_error {
+  bool exists{};
+  auto res = is_directory(api_path, exists);
+  if (res != api_error::success) {
+    return res;
+  }
+  if (exists) {
+    return api_error::directory_exists;
+  }
+
+  api_file file{};
+  res = get_file(api_path, file);
+  if (res != api_error::success) {
+    return res;
+  }
+
+  file_size = file.file_size;
+  return api_error::success;
+}
+
 auto base_provider::get_filesystem_item(const std::string &api_path,
                                         bool directory,
                                         filesystem_item &fsi) const