tvl-depot/absl/functional/internal/front_binder.h
Abseil Team bf86cfe165 Export of internal Abseil changes
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20b3acaff75d05315f272747956b01405adccafb by Greg Falcon <gfalcon@google.com>:

Re-import of CCTZ from GitHub, with new ABSL_NAMESPACE_ transform applied.

PiperOrigin-RevId: 285564474

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4d9e3fcabcea33c8b0b69f094ad2eddc0fa19557 by Derek Mauro <dmauro@google.com>:

Moves the disabling of a warning to before the function begins.

MSVC apparently requires this for warnings in the range 4700-4999.
https://docs.microsoft.com/en-us/cpp/preprocessor/warning?redirectedfrom=MSDN&view=vs-2019

PiperOrigin-RevId: 285516232

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4a060cbeda76e89693c50276ae5b62cbf0fff39a by Derek Mauro <dmauro@google.com>:

MSVC: Fixes uniform_real_distribution_test in opt mode

Disables a constant arithmetic overflow warning in a test that tests
the behavior on overflow. This should be tested because a user might
have this warning disabled.

PiperOrigin-RevId: 285452242

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548ab2f4cbe59bd6f6bf493af4f9ea765c4fa949 by Andy Soffer <asoffer@google.com>:

Release absl::bind_front, a C++11-compliant work-alike type for the C++20
std::bind_front.

PiperOrigin-RevId: 285247872
GitOrigin-RevId: 20b3acaff75d05315f272747956b01405adccafb
Change-Id: I00fe45939246cba9bfc7be375d67787d2eb57cd3
2019-12-16 15:25:20 -05:00

95 lines
3.6 KiB
C++

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