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rust-rocksdb/include/rocksdb/functor_wrapper.h

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1.5 KiB

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <functional>
#include <memory>
#include <utility>
#include "rocksdb/rocksdb_namespace.h"
namespace ROCKSDB_NAMESPACE {
namespace detail {
template <std::size_t...>
struct IndexSequence {};
template <std::size_t N, std::size_t... Next>
struct IndexSequenceHelper
: public IndexSequenceHelper<N - 1U, N - 1U, Next...> {};
template <std::size_t... Next>
struct IndexSequenceHelper<0U, Next...> {
using type = IndexSequence<Next...>;
};
template <std::size_t N>
using make_index_sequence = typename IndexSequenceHelper<N>::type;
template <typename Function, typename Tuple, size_t... I>
void call(Function f, Tuple t, IndexSequence<I...>) {
f(std::get<I>(t)...);
}
template <typename Function, typename Tuple>
void call(Function f, Tuple t) {
static constexpr auto size = std::tuple_size<Tuple>::value;
call(f, t, make_index_sequence<size>{});
}
} // namespace detail
template <typename... Args>
class FunctorWrapper {
public:
explicit FunctorWrapper(std::function<void(Args...)> functor, Args &&...args)
: functor_(std::move(functor)), args_(std::forward<Args>(args)...) {}
void invoke() { detail::call(functor_, args_); }
private:
std::function<void(Args...)> functor_;
std::tuple<Args...> args_;
};
} // namespace ROCKSDB_NAMESPACE