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1 /*
2  * Copyright (c) 2024 Huawei Device Co., Ltd.
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  *     http://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 #ifndef THREAD_SAFETY_ANNOTATIONS_H
17 #define THREAD_SAFETY_ANNOTATIONS_H
18 
19 // https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
20 // Enable thread safety attributes only with clang.
21 // The attributes can be safely erased when compiling with other compilers.
22 #if defined(__clang__) && (!defined(SWIG))
23 #define THREAD_ANNOTATION_ATTRIBUTE__(x)   __attribute__((x))
24 #else
25 #define THREAD_ANNOTATION_ATTRIBUTE__(x)   // no-op
26 #endif
27 
28 #define CAPABILITY(x) \
29   THREAD_ANNOTATION_ATTRIBUTE__(capability(x))
30 
31 #define SCOPED_CAPABILITY \
32   THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
33 
34 #define GUARDED_BY(x) \
35   THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
36 
37 #define PT_GUARDED_BY(x) \
38   THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x))
39 
40 #define ACQUIRED_BEFORE(...) \
41   THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(__VA_ARGS__))
42 
43 #define ACQUIRED_AFTER(...) \
44   THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(__VA_ARGS__))
45 
46 #define REQUIRES(...) \
47   THREAD_ANNOTATION_ATTRIBUTE__(requires_capability(__VA_ARGS__))
48 
49 #define REQUIRES_SHARED(...) \
50   THREAD_ANNOTATION_ATTRIBUTE__(requires_shared_capability(__VA_ARGS__))
51 
52 #define ACQUIRE(...) \
53   THREAD_ANNOTATION_ATTRIBUTE__(acquire_capability(__VA_ARGS__))
54 
55 #define ACQUIRE_SHARED(...) \
56   THREAD_ANNOTATION_ATTRIBUTE__(acquire_shared_capability(__VA_ARGS__))
57 
58 #define RELEASE(...) \
59   THREAD_ANNOTATION_ATTRIBUTE__(release_capability(__VA_ARGS__))
60 
61 #define RELEASE_SHARED(...) \
62   THREAD_ANNOTATION_ATTRIBUTE__(release_shared_capability(__VA_ARGS__))
63 
64 #define RELEASE_GENERIC(...) \
65   THREAD_ANNOTATION_ATTRIBUTE__(release_generic_capability(__VA_ARGS__))
66 
67 #define TRY_ACQUIRE(...) \
68   THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_capability(__VA_ARGS__))
69 
70 #define TRY_ACQUIRE_SHARED(...) \
71   THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_shared_capability(__VA_ARGS__))
72 
73 #define EXCLUDES(...) \
74   THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__))
75 
76 #define ASSERT_CAPABILITY(x) \
77   THREAD_ANNOTATION_ATTRIBUTE__(assert_capability(x))
78 
79 #define ASSERT_SHARED_CAPABILITY(x) \
80   THREAD_ANNOTATION_ATTRIBUTE__(assert_shared_capability(x))
81 
82 #define RETURN_CAPABILITY(x) \
83   THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
84 
85 #define NO_THREAD_SAFETY_ANALYSIS \
86   THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
87 
88 namespace OHOS::Rosen {
89 class CAPABILITY("mutex") SingleThreadGuard {};
90 
91 // ONLY used for those accessed ONLY on scene session manager thread.
92 // If other looper threads(NOT ffrt or ipc), define a new one.
93 constexpr SingleThreadGuard SCENE_GUARD;
94 
95 template <typename Guard>
96 struct SCOPED_CAPABILITY ScopedGuard final {
ScopedGuardfinal97     explicit ScopedGuard(const Guard& guard) ACQUIRE(guard) {}
RELEASEfinal98     ~ScopedGuard() RELEASE() {}
99 
100     ScopedGuard(const ScopedGuard&) = delete;
101     ScopedGuard& operator=(const ScopedGuard&) = delete;
102 };
103 
104 } // namespace OHOS::Rosen
105 
106 // Use this for lambdas. THREAD_SAFETY_GUARD is preferred.
107 #define LOCK_GUARD(guard)  \
108     ACQUIRE(guard) RELEASE(guard)
109 
110 // Use this for expressions. THREAD_SAFETY_GUARD is preferred.
111 #define LOCK_GUARD_TWO(guard, expr)  \
112     (OHOS::Rosen::ScopedGuard(guard), expr)
113 
114 // Use this when LOCK_GUARD_TWO/THREAD_SAFETY_GUARD works failed.
115 #define LOCK_GUARD_EXPR(guard, expr)           \
116     [&] {                                      \
117         OHOS::Rosen::ScopedGuard lock(guard);  \
118         return (expr);                         \
119     }()
120 
121 // Do not use this.
122 #define CREATE_THREAD_SAFETY_GUARD(opt1, opt2, guard, ...) guard
123 
124 // Use THREAD_SAFETY_GUARD for common cases, including LOCK_GUARD and LOCK_GUARD_TWO.
125 #define THREAD_SAFETY_GUARD(...) \
126     CREATE_THREAD_SAFETY_GUARD(__VA_ARGS__, LOCK_GUARD_TWO, LOCK_GUARD,)(__VA_ARGS__)
127 
128 #endif // THREAD_SAFETY_ANNOTATIONS_H
129