1/*
2 * Copyright (C) 2014 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 LINKEDBLOCKINGQUEUE_H_
18#define LINKEDBLOCKINGQUEUE_H_
19
20#include <utils/List.h>
21#include <utils/Mutex.h>
22#include <utils/Condition.h>
23
24namespace android {
25
26template<typename T>
27class LinkedBlockingQueue {
28    List<T> mList;
29    Mutex mLock;
30    Condition mContentAvailableCondition;
31
32    T front(bool remove) {
33        Mutex::Autolock autolock(mLock);
34        while (mList.empty()) {
35            mContentAvailableCondition.wait(mLock);
36        }
37        T e = *(mList.begin());
38        if (remove) {
39            mList.erase(mList.begin());
40        }
41        return e;
42    }
43
44    DISALLOW_EVIL_CONSTRUCTORS(LinkedBlockingQueue);
45
46public:
47    LinkedBlockingQueue() {
48    }
49
50    ~LinkedBlockingQueue() {
51    }
52
53    bool empty() {
54        Mutex::Autolock autolock(mLock);
55        return mList.empty();
56    }
57
58    void clear() {
59        Mutex::Autolock autolock(mLock);
60        mList.clear();
61    }
62
63    T peek() {
64        return front(false);
65    }
66
67    T take() {
68        return front(true);
69    }
70
71    void push(T e) {
72        Mutex::Autolock autolock(mLock);
73        mList.push_back(e);
74        mContentAvailableCondition.signal();
75    }
76};
77
78} /* namespace android */
79#endif /* LINKEDBLOCKINGQUEUE_H_ */
80