New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/search/cancel_exception.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "base/cancellable.hpp"
+#include "base/exception.hpp"
+
+namespace search
+{
+// This exception can be thrown from the deep darkness of search and
+// geometry retrieval for fast cancellation of time-consuming tasks.
+DECLARE_EXCEPTION(CancelException, RootException);
+
+inline void BailIfCancelled(base::Cancellable const & cancellable)
+{
+  if (cancellable.IsCancelled())
+    MYTHROW(CancelException, ("Cancelled"));
+}
+}  // namespace search