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#pragma once
///@file
#include "store-api.hh"
namespace nix {
/**
* Helper to try downcasting a Store with a nice method if it fails.
*
* This is basically an alternative to the user-facing part of
* Store::unsupported that allows us to still have a nice message but
* better interface design.
*/
template<typename T>
T & require(Store & store)
{
auto * castedStore = dynamic_cast<T *>(&store);
if (!castedStore)
throw UsageError("%s not supported by store '%s'", T::operationName, store.getUri());
return *castedStore;
}
}
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