1 | /* |
2 | * Copyright 2017-present Facebook, Inc. |
3 | * |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. |
6 | * You may obtain a copy of the License at |
7 | * |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * |
10 | * Unless required by applicable law or agreed to in writing, software |
11 | * distributed under the License is distributed on an "AS IS" BASIS, |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
13 | * See the License for the specific language governing permissions and |
14 | * limitations under the License. |
15 | */ |
16 | #pragma once |
17 | |
18 | #include <chrono> |
19 | #include <exception> |
20 | #include <stdexcept> |
21 | |
22 | #include <glog/logging.h> |
23 | |
24 | #include <folly/CPortability.h> |
25 | #include <folly/Optional.h> |
26 | |
27 | namespace folly { |
28 | |
29 | // Some queue implementations (for example, LifoSemMPMCQueue or |
30 | // PriorityLifoSemMPMCQueue) support both blocking (BLOCK) and |
31 | // non-blocking (THROW) behaviors. |
32 | enum class QueueBehaviorIfFull { THROW, BLOCK }; |
33 | |
34 | class FOLLY_EXPORT QueueFullException : public std::runtime_error { |
35 | using std::runtime_error::runtime_error; // Inherit constructors. |
36 | }; |
37 | |
38 | struct BlockingQueueAddResult { |
39 | BlockingQueueAddResult(bool reused = false) : reusedThread(reused) {} |
40 | bool reusedThread; |
41 | }; |
42 | |
43 | template <class T> |
44 | class BlockingQueue { |
45 | public: |
46 | virtual ~BlockingQueue() = default; |
47 | // Adds item to the queue (with priority). |
48 | // |
49 | // Returns true if an existing thread was able to work on it (used |
50 | // for dynamically sizing thread pools), false otherwise. Return false |
51 | // if this feature is not supported. |
52 | virtual BlockingQueueAddResult add(T item) = 0; |
53 | virtual BlockingQueueAddResult addWithPriority( |
54 | T item, |
55 | int8_t /* priority */) { |
56 | return add(std::move(item)); |
57 | } |
58 | virtual uint8_t getNumPriorities() { |
59 | return 1; |
60 | } |
61 | virtual T take() = 0; |
62 | virtual folly::Optional<T> try_take_for(std::chrono::milliseconds time) = 0; |
63 | virtual size_t size() = 0; |
64 | }; |
65 | |
66 | } // namespace folly |
67 | |