Abseil Common Libraries (C++) (grcp 依赖)
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95 lines
3.6 KiB
95 lines
3.6 KiB
// Copyright 2018 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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// Implementation details for `absl::bind_front()`. |
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#ifndef ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_ |
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#define ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_ |
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#include <cstddef> |
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#include <type_traits> |
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#include <utility> |
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#include "absl/base/internal/invoke.h" |
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#include "absl/container/internal/compressed_tuple.h" |
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#include "absl/meta/type_traits.h" |
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#include "absl/utility/utility.h" |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace functional_internal { |
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// Invoke the method, expanding the tuple of bound arguments. |
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template <class R, class Tuple, size_t... Idx, class... Args> |
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R Apply(Tuple&& bound, absl::index_sequence<Idx...>, Args&&... free) { |
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return base_internal::invoke( |
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absl::forward<Tuple>(bound).template get<Idx>()..., |
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absl::forward<Args>(free)...); |
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} |
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template <class F, class... BoundArgs> |
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class FrontBinder { |
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using BoundArgsT = absl::container_internal::CompressedTuple<F, BoundArgs...>; |
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using Idx = absl::make_index_sequence<sizeof...(BoundArgs) + 1>; |
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BoundArgsT bound_args_; |
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public: |
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template <class... Ts> |
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constexpr explicit FrontBinder(absl::in_place_t, Ts&&... ts) |
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: bound_args_(absl::forward<Ts>(ts)...) {} |
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template <class... FreeArgs, class R = base_internal::invoke_result_t< |
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F&, BoundArgs&..., FreeArgs&&...>> |
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R operator()(FreeArgs&&... free_args) & { |
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return functional_internal::Apply<R>(bound_args_, Idx(), |
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absl::forward<FreeArgs>(free_args)...); |
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} |
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template <class... FreeArgs, |
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class R = base_internal::invoke_result_t< |
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const F&, const BoundArgs&..., FreeArgs&&...>> |
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R operator()(FreeArgs&&... free_args) const& { |
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return functional_internal::Apply<R>(bound_args_, Idx(), |
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absl::forward<FreeArgs>(free_args)...); |
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} |
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template <class... FreeArgs, class R = base_internal::invoke_result_t< |
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F&&, BoundArgs&&..., FreeArgs&&...>> |
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R operator()(FreeArgs&&... free_args) && { |
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// This overload is called when *this is an rvalue. If some of the bound |
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// arguments are stored by value or rvalue reference, we move them. |
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return functional_internal::Apply<R>(absl::move(bound_args_), Idx(), |
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absl::forward<FreeArgs>(free_args)...); |
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} |
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template <class... FreeArgs, |
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class R = base_internal::invoke_result_t< |
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const F&&, const BoundArgs&&..., FreeArgs&&...>> |
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R operator()(FreeArgs&&... free_args) const&& { |
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// This overload is called when *this is an rvalue. If some of the bound |
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// arguments are stored by value or rvalue reference, we move them. |
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return functional_internal::Apply<R>(absl::move(bound_args_), Idx(), |
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absl::forward<FreeArgs>(free_args)...); |
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} |
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}; |
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template <class F, class... BoundArgs> |
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using bind_front_t = FrontBinder<decay_t<F>, absl::decay_t<BoundArgs>...>; |
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} // namespace functional_internal |
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ABSL_NAMESPACE_END |
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} // namespace absl |
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#endif // ABSL_FUNCTIONAL_INTERNAL_FRONT_BINDER_H_
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