fixed_size_blocking_queue.h revision 042f73e3b7f019c818f69b2c097c4b6f9db839b5 
1/*
2 * Copyright (C) 2016 The Android Open Source Project
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
17#ifndef CHRE_UTIL_FIXED_SIZE_BLOCKING_QUEUE_H_
18#define CHRE_UTIL_FIXED_SIZE_BLOCKING_QUEUE_H_
19
20#include <deque>
21
22#include "chre/platform/condition_variable.h"
23#include "chre/platform/mutex.h"
24#include "chre/util/array_queue.h"
25#include "chre/util/non_copyable.h"
26
27namespace chre {
28
29/**
30 * Implements a thread-safe blocking queue that blocks when popping an element
31 * if necessary.
32 */
33template <typename ElementType, size_t kSize>
34class FixedSizeBlockingQueue : public NonCopyable {
35 public:
36  /**
37   * Pushes an element into the queue and notifies any waiting threads that an
38   * element is available.
39   *
40   * @param The element to be pushed.
41   *
42   * @return true if the element is pushed successfully.
43   */
44  bool push(const ElementType& element);
45
46  /**
47   * Pops one element from the queue. If the queue is empty, the thread will
48   * block until an element has been pushed.
49   *
50   * @return The element that was popped.
51   */
52  ElementType pop();
53
54  /**
55   * Determines whether or not the BlockingQueue is empty.
56   */
57  bool empty();
58
59 private:
60  //! The mutex used to ensure thread-safety.
61  Mutex mMutex;
62
63  //! The condition variable used to implement the blocking behavior of the
64  //! queue.
65  ConditionVariable mConditionVariable;
66
67  //! The underlying fixed size container backing the queue.
68  ArrayQueue<ElementType, kSize> mQueue;
69};
70
71}  // namespace chre
72
73#include "chre/util/fixed_size_blocking_queue_impl.h"
74
75#endif  // CHRE_UTIL_FIXED_SIZE_BLOCKING_QUEUE_H_
76