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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 | #ifndef ARROW_COUNTING_SEMAPHORE_H | |
19 | #define ARROW_COUNTING_SEMAPHORE_H | |
20 | ||
21 | #include <memory> | |
22 | ||
23 | #include "arrow/status.h" | |
24 | ||
25 | namespace arrow { | |
26 | namespace util { | |
27 | ||
28 | /// \brief Simple mutex-based counting semaphore with timeout | |
29 | class ARROW_EXPORT CountingSemaphore { | |
30 | public: | |
31 | /// \brief Create an instance with initial_avail starting permits | |
32 | /// | |
33 | /// \param[in] initial_avail The semaphore will start with this many permits available | |
34 | /// \param[in] timeout_seconds A timeout to be applied to all operations. Operations | |
35 | /// will return Status::Invalid if this timeout elapses | |
36 | explicit CountingSemaphore(uint32_t initial_avail = 0, double timeout_seconds = 10); | |
37 | ~CountingSemaphore(); | |
38 | /// \brief Block until num_permits permits are available | |
39 | Status Acquire(uint32_t num_permits); | |
40 | /// \brief Make num_permits permits available | |
41 | Status Release(uint32_t num_permits); | |
42 | /// \brief Wait until num_waiters are waiting on permits | |
43 | /// | |
44 | /// This method is non-standard but useful in unit tests to ensure sequencing | |
45 | Status WaitForWaiters(uint32_t num_waiters); | |
46 | /// \brief Immediately time out any waiters | |
47 | /// | |
48 | /// This method will return Status::OK only if there were no waiters to time out. | |
49 | /// Once closed any operation on this instance will return an invalid status. | |
50 | Status Close(); | |
51 | ||
52 | private: | |
53 | class Impl; | |
54 | std::unique_ptr<Impl> impl_; | |
55 | }; | |
56 | ||
57 | } // namespace util | |
58 | } // namespace arrow | |
59 | ||
60 | #endif // ARROW_COUNTING_SEMAPHORE_H |