/Users/deen/code/yugabyte-db/src/yb/util/semaphore.h
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1 | | // Licensed to the Apache Software Foundation (ASF) under one |
2 | | // or more contributor license agreements. See the NOTICE file |
3 | | // distributed with this work for additional information |
4 | | // regarding copyright ownership. The ASF licenses this file |
5 | | // to you under the Apache License, Version 2.0 (the |
6 | | // "License"); you may not use this file except in compliance |
7 | | // with the License. You may obtain a copy of the License at |
8 | | // |
9 | | // http://www.apache.org/licenses/LICENSE-2.0 |
10 | | // |
11 | | // Unless required by applicable law or agreed to in writing, |
12 | | // software distributed under the License is distributed on an |
13 | | // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
14 | | // KIND, either express or implied. See the License for the |
15 | | // specific language governing permissions and limitations |
16 | | // under the License. |
17 | | // |
18 | | // The following only applies to changes made to this file as part of YugaByte development. |
19 | | // |
20 | | // Portions Copyright (c) YugaByte, Inc. |
21 | | // |
22 | | // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
23 | | // in compliance with the License. You may obtain a copy of the License at |
24 | | // |
25 | | // http://www.apache.org/licenses/LICENSE-2.0 |
26 | | // |
27 | | // Unless required by applicable law or agreed to in writing, software distributed under the License |
28 | | // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
29 | | // or implied. See the License for the specific language governing permissions and limitations |
30 | | // under the License. |
31 | | // |
32 | | #ifndef YB_UTIL_SEMAPHORE_H |
33 | | #define YB_UTIL_SEMAPHORE_H |
34 | | |
35 | | #include <semaphore.h> |
36 | | #if defined(__APPLE__) |
37 | | #include <dispatch/dispatch.h> |
38 | | #include "yb/util/atomic.h" |
39 | | #endif // define(__APPLE__) |
40 | | |
41 | | #include "yb/gutil/macros.h" |
42 | | #include "yb/gutil/port.h" |
43 | | #include "yb/util/monotime.h" |
44 | | |
45 | | namespace yb { |
46 | | |
47 | | // Wrapper for POSIX semaphores. |
48 | | class Semaphore { |
49 | | public: |
50 | | // Initialize the semaphore with the specified capacity. |
51 | | explicit Semaphore(int capacity); |
52 | | ~Semaphore(); |
53 | | |
54 | | // Acquire the semaphore. |
55 | | void Acquire(); |
56 | | |
57 | | // Acquire the semaphore within the given timeout. Returns true if successful. |
58 | | bool TimedAcquire(const MonoDelta& timeout); |
59 | | |
60 | | // Try to acquire the semaphore immediately. Returns false if unsuccessful. |
61 | | bool TryAcquire(); |
62 | | |
63 | | // Release the semaphore. |
64 | | void Release(); |
65 | | |
66 | | // Get the current value of the semaphore. |
67 | | int GetValue(); |
68 | | |
69 | | // Boost-compatible wrappers. |
70 | 0 | void lock() { Acquire(); } |
71 | 1 | void unlock() { Release(); } |
72 | 2 | bool try_lock() { return TryAcquire(); } |
73 | | |
74 | | private: |
75 | | #if !defined(__APPLE__) |
76 | | // Log a fatal error message. Separated out to keep the main functions |
77 | | // as small as possible in terms of code size. |
78 | | void Fatal(const char* action) ATTRIBUTE_NORETURN; |
79 | | #endif // !define(__APPLE__) |
80 | | |
81 | | #if defined(__APPLE__) |
82 | | std::atomic<int32_t> count_; |
83 | | std::condition_variable cv_; |
84 | | // Mutex to use with the condition variable cv_. |
85 | | std::mutex mutex_; |
86 | | #else |
87 | | sem_t sem_; |
88 | | #endif // define(__APPLE__) |
89 | | DISALLOW_COPY_AND_ASSIGN(Semaphore); |
90 | | }; |
91 | | |
92 | | } // namespace yb |
93 | | #endif /* YB_UTIL_SEMAPHORE_H */ |