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#include "CondVar.h"
22#include "NfcJniUtil.h"
23
24#include <cutils/log.h>
25#include <errno.h>
26
27
28/*******************************************************************************
29**
30** Function:        CondVar
31**
32** Description:     Initialize member variables.
33**
34** Returns:         None.
35**
36*******************************************************************************/
37CondVar::CondVar ()
38{
39    memset (&mCondition, 0, sizeof(mCondition));
40    int const res = pthread_cond_init (&mCondition, NULL);
41    if (res)
42    {
43        ALOGE ("CondVar::CondVar: fail init; error=0x%X", res);
44    }
45}
46
47
48/*******************************************************************************
49**
50** Function:        ~CondVar
51**
52** Description:     Cleanup all resources.
53**
54** Returns:         None.
55**
56*******************************************************************************/
57CondVar::~CondVar ()
58{
59    int const res = pthread_cond_destroy (&mCondition);
60    if (res)
61    {
62        ALOGE ("CondVar::~CondVar: fail destroy; error=0x%X", res);
63    }
64}
65
66
67/*******************************************************************************
68**
69** Function:        wait
70**
71** Description:     Block the caller and wait for a condition.
72**
73** Returns:         None.
74**
75*******************************************************************************/
76void CondVar::wait (Mutex& mutex)
77{
78    int const res = pthread_cond_wait (&mCondition, mutex.nativeHandle());
79    if (res)
80    {
81        ALOGE ("CondVar::wait: fail wait; error=0x%X", res);
82    }
83}
84
85
86/*******************************************************************************
87**
88** Function:        wait
89**
90** Description:     Block the caller and wait for a condition.
91**                  millisec: Timeout in milliseconds.
92**
93** Returns:         True if wait is successful; false if timeout occurs.
94**
95*******************************************************************************/
96bool CondVar::wait (Mutex& mutex, long millisec)
97{
98    bool retVal = false;
99    struct timespec absoluteTime;
100
101    if (clock_gettime (CLOCK_MONOTONIC, &absoluteTime) == -1)
102    {
103        ALOGE ("CondVar::wait: fail get time; errno=0x%X", errno);
104    }
105    else
106    {
107        absoluteTime.tv_sec += millisec / 1000;
108        long ns = absoluteTime.tv_nsec + ((millisec % 1000) * 1000000);
109        if (ns > 1000000000)
110        {
111            absoluteTime.tv_sec++;
112            absoluteTime.tv_nsec = ns - 1000000000;
113        }
114        else
115            absoluteTime.tv_nsec = ns;
116    }
117
118    //pthread_cond_timedwait_monotonic_np() is an Android-specific function
119    //declared in /development/ndk/platforms/android-9/include/pthread.h;
120    //it uses monotonic clock.
121    //the standard pthread_cond_timedwait() uses realtime clock.
122    int waitResult = pthread_cond_timedwait_monotonic_np (&mCondition, mutex.nativeHandle(), &absoluteTime);
123    if ((waitResult != 0) && (waitResult != ETIMEDOUT))
124        ALOGE ("CondVar::wait: fail timed wait; error=0x%X", waitResult);
125    retVal = (waitResult == 0); //waited successfully
126    return retVal;
127}
128
129
130/*******************************************************************************
131**
132** Function:        notifyOne
133**
134** Description:     Unblock the waiting thread.
135**
136** Returns:         None.
137**
138*******************************************************************************/
139void CondVar::notifyOne ()
140{
141    int const res = pthread_cond_signal (&mCondition);
142    if (res)
143    {
144        ALOGE ("CondVar::notifyOne: fail signal; error=0x%X", res);
145    }
146}
147
148