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
96
97
|
// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_CONTAINERS_ADAPTERS_INTERNAL_H_
#define BASE_CONTAINERS_ADAPTERS_INTERNAL_H_
#include <stddef.h>
#include <iterator>
#include <ranges>
#include <utility>
#include "base/compiler_specific.h"
#include "base/memory/raw_ptr_exclusion.h"
namespace base::internal {
template <typename Range>
class RangeOfRvaluesAdapter;
template <typename Range>
class ReversedAdapter;
} // namespace base::internal
// This is technically correct, but presently always evaluates to false since
// `RangeAsRvalues()` bans non-borrowed ranges.
template <typename Range>
inline constexpr bool std::ranges::enable_borrowed_range<
base::internal::RangeOfRvaluesAdapter<Range>> =
std::ranges::borrowed_range<Range>;
template <typename Range>
inline constexpr bool
std::ranges::enable_borrowed_range<base::internal::ReversedAdapter<Range>> =
std::ranges::borrowed_range<Range>;
namespace base::internal {
template <typename Range>
class RangeOfRvaluesAdapter {
public:
explicit RangeOfRvaluesAdapter(Range&& range LIFETIME_BOUND)
: range_(std::forward<Range>(range)) {}
RangeOfRvaluesAdapter(const RangeOfRvaluesAdapter&) = default;
RangeOfRvaluesAdapter& operator=(const RangeOfRvaluesAdapter&) = delete;
auto size() const
requires std::ranges::sized_range<Range>
{
return std::ranges::size(range_);
}
auto begin() { return std::make_move_iterator(std::ranges::begin(range_)); }
auto end() { return std::make_move_iterator(std::ranges::end(range_)); }
private:
// RAW_PTR_EXCLUSION: References a STACK_ALLOCATED class. It is only used
// inside for loops. Ideally, the container being iterated over should be the
// one held via a raw_ref/raw_ptrs.
RAW_PTR_EXCLUSION Range&& range_;
};
// Internal adapter class for implementing base::Reversed.
// TODO(crbug.com/378623811): Parts of this (e.g. the `size()` helper) should be
// extracted to a base template that can be shared/reused. In addition, this
// should be constrained to Ts that satisfy the std::ranges::range concept.
template <typename Range>
class ReversedAdapter {
public:
explicit ReversedAdapter(Range&& range LIFETIME_BOUND)
: range_(std::forward<Range>(range)) {}
ReversedAdapter(const ReversedAdapter&) = default;
ReversedAdapter& operator=(const ReversedAdapter&) = delete;
auto begin() { return std::rbegin(range_); }
auto begin() const { return std::rbegin(range_); }
auto cbegin() const { return std::crbegin(range_); }
auto end() { return std::rend(range_); }
auto end() const { return std::rend(range_); }
auto cend() const { return std::crend(range_); }
auto size() const
requires std::ranges::sized_range<Range>
{
return std::ranges::size(range_);
}
private:
// RAW_PTR_EXCLUSION: References a STACK_ALLOCATED class. It is only used
// inside for loops. Ideally, the container being iterated over should be the
// one held via a raw_ref/raw_ptrs.
RAW_PTR_EXCLUSION Range&& range_;
};
} // namespace base::internal
#endif // BASE_CONTAINERS_ADAPTERS_INTERNAL_H_
|
