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