1 files changed, 24 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_function_ref.hh b/source/blender/blenlib/BLI_function_ref.hh
index 57fffdc09b4..38e1ba593c5 100644
--- a/source/blender/blenlib/BLI_function_ref.hh
+++ b/source/blender/blenlib/BLI_function_ref.hh
@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <optional>
 #include <type_traits>
 #include <utility>
 
@@ -139,6 +140,29 @@ template<typename Ret, typename... Params> class FunctionRef<Ret(Params...)> {
     return callback_(callable_, std::forward<Params>(params)...);
   }
 
+  using OptionalReturnValue = std::conditional_t<std::is_void_v<Ret>, void, std::optional<Ret>>;
+
+  /**
+   * Calls the referenced function if it is available.
+   * The return value is of type `std::optional<Ret>` if `Ret` is not `void`.
+   * Otherwise the return type is `void`.
+   */
+  OptionalReturnValue call_safe(Params... params) const
+  {
+    if constexpr (std::is_void_v<Ret>) {
+      if (callback_ == nullptr) {
+        return;
+      }
+      callback_(callable_, std::forward<Params>(params)...);
+    }
+    else {
+      if (callback_ == nullptr) {
+        return {};
+      }
+      return callback_(callable_, std::forward<Params>(params)...);
+    }
+  }
+
   /**
    * Returns true, when the `FunctionRef` references a function currently.
    * If this returns false, the `FunctionRef` must not be called.