1 /*
2  * Copyright (C) 2012 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 /*
18  *  Encapsulate a condition variable for thread synchronization.
19  */
20 
21 #pragma once
22 #include <pthread.h>
23 #include "Mutex.h"
24 
25 
26 class CondVar
27 {
28 public:
29     /*******************************************************************************
30     **
31     ** Function:        CondVar
32     **
33     ** Description:     Initialize member variables.
34     **
35     ** Returns:         None.
36     **
37     *******************************************************************************/
38     CondVar ();
39 
40 
41     /*******************************************************************************
42     **
43     ** Function:        ~CondVar
44     **
45     ** Description:     Cleanup all resources.
46     **
47     ** Returns:         None.
48     **
49     *******************************************************************************/
50     ~CondVar ();
51 
52 
53     /*******************************************************************************
54     **
55     ** Function:        wait
56     **
57     ** Description:     Block the caller and wait for a condition.
58     **
59     ** Returns:         None.
60     **
61     *******************************************************************************/
62     void wait (Mutex& mutex);
63 
64 
65     /*******************************************************************************
66     **
67     ** Function:        wait
68     **
69     ** Description:     Block the caller and wait for a condition.
70     **                  millisec: Timeout in milliseconds.
71     **
72     ** Returns:         True if wait is successful; false if timeout occurs.
73     **
74     *******************************************************************************/
75     bool wait (Mutex& mutex, long millisec);
76 
77 
78     /*******************************************************************************
79     **
80     ** Function:        notifyOne
81     **
82     ** Description:     Unblock the waiting thread.
83     **
84     ** Returns:         None.
85     **
86     *******************************************************************************/
87     void notifyOne ();
88 
89 private:
90     pthread_cond_t mCondition;
91 };
92