1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
// 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_
|
