[core] Move mbgl::Pass and mbgl::PassRefPtr to a separate header

1 files changed, 24 insertions, 0 deletions

diff --git a/include/mbgl/util/pass_types.hpp b/include/mbgl/util/pass_types.hpp
new file mode 100644
index 0000000000..5415a3177f
--- /dev/null
+++ b/include/mbgl/util/pass_types.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <memory>
+
+namespace mbgl {
+
+// Using this type as a return type enforces the client to retain the returned object.
+template <typename T>
+class Pass {
+public:
+    Pass(T&& obj_) : obj(std::forward<T>(obj_)) {}
+    Pass(Pass&&) noexcept = default;
+    Pass(const Pass&) = delete;
+    Pass& operator=(const Pass&) = delete;
+    operator T() && { return std::move(obj); }
+
+private:
+    T obj;
+};
+
+template <typename T>
+using PassRefPtr = Pass<std::shared_ptr<T>>;
+
+} // namespace mbgl
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