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#pragma once
#include <type_traits>
#include <utility>
namespace base
{
// This enum is used to control the flow of ForEach invocations.
enum class ControlFlow
{
Break,
Continue
};
// A wrapper that calls |fn| with arguments |args|.
// To avoid excessive calls, |fn| may signal the end of execution via its return value,
// which should then be checked by the wrapper's user.
template <typename Fn>
class ControlFlowWrapper
{
public:
template <typename Gn>
explicit ControlFlowWrapper(Gn && gn) : m_fn(std::forward<Gn>(gn))
{
}
template <typename... Args>
std::enable_if_t<std::is_same<std::result_of_t<Fn(Args...)>, base::ControlFlow>::value,
base::ControlFlow>
operator()(Args &&... args)
{
return m_fn(std::forward<Args>(args)...);
}
template <typename... Args>
std::enable_if_t<std::is_same<std::result_of_t<Fn(Args...)>, void>::value, base::ControlFlow>
operator()(Args &&... args)
{
m_fn(std::forward<Args>(args)...);
return ControlFlow::Continue;
}
private:
Fn m_fn;
};
} // namespace base
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