Coverage Report

Created: 2023-09-25 06:27

/src/abseil-cpp/absl/cleanup/cleanup.h
Line
Count
Source
1
// Copyright 2021 The Abseil Authors.
2
//
3
// Licensed under the Apache License, Version 2.0 (the "License");
4
// you may not use this file except in compliance with the License.
5
// You may obtain a copy of the License at
6
//
7
//      https://www.apache.org/licenses/LICENSE-2.0
8
//
9
// Unless required by applicable law or agreed to in writing, software
10
// distributed under the License is distributed on an "AS IS" BASIS,
11
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12
// See the License for the specific language governing permissions and
13
// limitations under the License.
14
//
15
// -----------------------------------------------------------------------------
16
// File: cleanup.h
17
// -----------------------------------------------------------------------------
18
//
19
// `absl::Cleanup` implements the scope guard idiom, invoking the contained
20
// callback's `operator()() &&` on scope exit.
21
//
22
// Example:
23
//
24
// ```
25
//   absl::Status CopyGoodData(const char* source_path, const char* sink_path) {
26
//     FILE* source_file = fopen(source_path, "r");
27
//     if (source_file == nullptr) {
28
//       return absl::NotFoundError("No source file");  // No cleanups execute
29
//     }
30
//
31
//     // C++17 style cleanup using class template argument deduction
32
//     absl::Cleanup source_closer = [source_file] { fclose(source_file); };
33
//
34
//     FILE* sink_file = fopen(sink_path, "w");
35
//     if (sink_file == nullptr) {
36
//       return absl::NotFoundError("No sink file");  // First cleanup executes
37
//     }
38
//
39
//     // C++11 style cleanup using the factory function
40
//     auto sink_closer = absl::MakeCleanup([sink_file] { fclose(sink_file); });
41
//
42
//     Data data;
43
//     while (ReadData(source_file, &data)) {
44
//       if (!data.IsGood()) {
45
//         absl::Status result = absl::FailedPreconditionError("Read bad data");
46
//         return result;  // Both cleanups execute
47
//       }
48
//       SaveData(sink_file, &data);
49
//     }
50
//
51
//     return absl::OkStatus();  // Both cleanups execute
52
//   }
53
// ```
54
//
55
// Methods:
56
//
57
// `std::move(cleanup).Cancel()` will prevent the callback from executing.
58
//
59
// `std::move(cleanup).Invoke()` will execute the callback early, before
60
// destruction, and prevent the callback from executing in the destructor.
61
//
62
// Usage:
63
//
64
// `absl::Cleanup` is not an interface type. It is only intended to be used
65
// within the body of a function. It is not a value type and instead models a
66
// control flow construct. Check out `defer` in Golang for something similar.
67
68
#ifndef ABSL_CLEANUP_CLEANUP_H_
69
#define ABSL_CLEANUP_CLEANUP_H_
70
71
#include <utility>
72
73
#include "absl/base/config.h"
74
#include "absl/base/macros.h"
75
#include "absl/cleanup/internal/cleanup.h"
76
77
namespace absl {
78
ABSL_NAMESPACE_BEGIN
79
80
template <typename Arg, typename Callback = void()>
81
class ABSL_MUST_USE_RESULT Cleanup final {
82
  static_assert(cleanup_internal::WasDeduced<Arg>(),
83
                "Explicit template parameters are not supported.");
84
85
  static_assert(cleanup_internal::ReturnsVoid<Callback>(),
86
                "Callbacks that return values are not supported.");
87
88
 public:
89
3.24M
  Cleanup(Callback callback) : storage_(std::move(callback)) {}  // NOLINT
log_sink_set.cc:absl::Cleanup<absl::cleanup_internal::Tag, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::LogToSinks(absl::LogEntry const&, absl::Span<absl::LogSink*>, bool)::{lambda()#1}>::Cleanup({lambda()#1})
Line
Count
Source
89
3.24M
  Cleanup(Callback callback) : storage_(std::move(callback)) {}  // NOLINT
Unexecuted instantiation: log_sink_set.cc:absl::Cleanup<absl::cleanup_internal::Tag, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::FlushLogSinks()::{lambda()#1}>::Cleanup({lambda()#1})
90
91
  Cleanup(Cleanup&& other) = default;
92
93
  void Cancel() && {
94
    ABSL_HARDENING_ASSERT(storage_.IsCallbackEngaged());
95
    storage_.DestroyCallback();
96
  }
97
98
  void Invoke() && {
99
    ABSL_HARDENING_ASSERT(storage_.IsCallbackEngaged());
100
    storage_.InvokeCallback();
101
    storage_.DestroyCallback();
102
  }
103
104
3.24M
  ~Cleanup() {
105
3.24M
    if (storage_.IsCallbackEngaged()) {
106
3.24M
      storage_.InvokeCallback();
107
3.24M
      storage_.DestroyCallback();
108
3.24M
    }
109
3.24M
  }
log_sink_set.cc:absl::Cleanup<absl::cleanup_internal::Tag, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::LogToSinks(absl::LogEntry const&, absl::Span<absl::LogSink*>, bool)::{lambda()#1}>::~Cleanup()
Line
Count
Source
104
3.24M
  ~Cleanup() {
105
3.24M
    if (storage_.IsCallbackEngaged()) {
106
3.24M
      storage_.InvokeCallback();
107
3.24M
      storage_.DestroyCallback();
108
3.24M
    }
109
3.24M
  }
Unexecuted instantiation: log_sink_set.cc:absl::Cleanup<absl::cleanup_internal::Tag, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::FlushLogSinks()::{lambda()#1}>::~Cleanup()
110
111
 private:
112
  cleanup_internal::Storage<Callback> storage_;
113
};
114
115
// `absl::Cleanup c = /* callback */;`
116
//
117
// C++17 type deduction API for creating an instance of `absl::Cleanup`
118
#if defined(ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION)
119
template <typename Callback>
120
Cleanup(Callback callback) -> Cleanup<cleanup_internal::Tag, Callback>;
121
#endif  // defined(ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION)
122
123
// `auto c = absl::MakeCleanup(/* callback */);`
124
//
125
// C++11 type deduction API for creating an instance of `absl::Cleanup`
126
template <typename... Args, typename Callback>
127
3.24M
absl::Cleanup<cleanup_internal::Tag, Callback> MakeCleanup(Callback callback) {
128
3.24M
  static_assert(cleanup_internal::WasDeduced<cleanup_internal::Tag, Args...>(),
129
3.24M
                "Explicit template parameters are not supported.");
130
131
3.24M
  static_assert(cleanup_internal::ReturnsVoid<Callback>(),
132
3.24M
                "Callbacks that return values are not supported.");
133
134
3.24M
  return {std::move(callback)};
135
3.24M
}
log_sink_set.cc:absl::Cleanup<absl::cleanup_internal::Tag, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::LogToSinks(absl::LogEntry const&, absl::Span<absl::LogSink*>, bool)::{lambda()#1}> absl::MakeCleanup<, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::LogToSinks(absl::LogEntry const&, absl::Span<absl::LogSink*>, bool)::{lambda()#1}>(absl::cleanup_internal::Tag)
Line
Count
Source
127
3.24M
absl::Cleanup<cleanup_internal::Tag, Callback> MakeCleanup(Callback callback) {
128
3.24M
  static_assert(cleanup_internal::WasDeduced<cleanup_internal::Tag, Args...>(),
129
3.24M
                "Explicit template parameters are not supported.");
130
131
3.24M
  static_assert(cleanup_internal::ReturnsVoid<Callback>(),
132
3.24M
                "Callbacks that return values are not supported.");
133
134
3.24M
  return {std::move(callback)};
135
3.24M
}
Unexecuted instantiation: log_sink_set.cc:absl::Cleanup<absl::cleanup_internal::Tag, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::FlushLogSinks()::{lambda()#1}> absl::MakeCleanup<, absl::log_internal::(anonymous namespace)::GlobalLogSinkSet::FlushLogSinks()::{lambda()#1}>(absl::cleanup_internal::Tag)
136
137
ABSL_NAMESPACE_END
138
}  // namespace absl
139
140
#endif  // ABSL_CLEANUP_CLEANUP_H_