1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _LIBS_UTILS_CONDITION_H
#define _LIBS_UTILS_CONDITION_H
#include <stdint.h>
#include <sys/types.h>
#include <time.h>
#if defined(HAVE_PTHREADS)
# include <pthread.h>
#endif
#include <utils/Errors.h>
#include <utils/Mutex.h>
#include <utils/Timers.h>
// ---------------------------------------------------------------------------
namespace android {
// ---------------------------------------------------------------------------
/*
* Condition variable class. The implementation is system-dependent.
*
* Condition variables are paired up with mutexes. Lock the mutex,
* call wait(), then either re-wait() if things aren't quite what you want,
* or unlock the mutex and continue. All threads calling wait() must
* use the same mutex for a given Condition.
*/
class Condition {
public:
enum {
PRIVATE = 0,
SHARED = 1
};
enum WakeUpType {
WAKE_UP_ONE = 0,
WAKE_UP_ALL = 1
};
Condition();
Condition(int type);
~Condition();
// Wait on the condition variable. Lock the mutex before calling.
status_t wait(Mutex& mutex);
// same with relative timeout
status_t waitRelative(Mutex& mutex, nsecs_t reltime);
// Signal the condition variable, allowing one thread to continue.
void signal();
// Signal the condition variable, allowing one or all threads to continue.
void signal(WakeUpType type) {
if (type == WAKE_UP_ONE) {
signal();
} else {
broadcast();
}
}
// Signal the condition variable, allowing all threads to continue.
void broadcast();
private:
#if defined(HAVE_PTHREADS)
pthread_cond_t mCond;
#else
void* mState;
#endif
};
// ---------------------------------------------------------------------------
#if defined(HAVE_PTHREADS)
inline Condition::Condition() {
pthread_cond_init(&mCond, NULL);
}
inline Condition::Condition(int type) {
if (type == SHARED) {
pthread_condattr_t attr;
pthread_condattr_init(&attr);
pthread_condattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
pthread_cond_init(&mCond, &attr);
pthread_condattr_destroy(&attr);
} else {
pthread_cond_init(&mCond, NULL);
}
}
inline Condition::~Condition() {
pthread_cond_destroy(&mCond);
}
inline status_t Condition::wait(Mutex& mutex) {
return -pthread_cond_wait(&mCond, &mutex.mMutex);
}
inline status_t Condition::waitRelative(Mutex& mutex, nsecs_t reltime) {
#if defined(HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE)
struct timespec ts;
ts.tv_sec = reltime/1000000000;
ts.tv_nsec = reltime%1000000000;
return -pthread_cond_timedwait_relative_np(&mCond, &mutex.mMutex, &ts);
#else // HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE
struct timespec ts;
#if defined(HAVE_POSIX_CLOCKS)
clock_gettime(CLOCK_REALTIME, &ts);
#else // HAVE_POSIX_CLOCKS
// we don't support the clocks here.
struct timeval t;
gettimeofday(&t, NULL);
ts.tv_sec = t.tv_sec;
ts.tv_nsec= t.tv_usec*1000;
#endif // HAVE_POSIX_CLOCKS
ts.tv_sec += reltime/1000000000;
ts.tv_nsec+= reltime%1000000000;
if (ts.tv_nsec >= 1000000000) {
ts.tv_nsec -= 1000000000;
ts.tv_sec += 1;
}
return -pthread_cond_timedwait(&mCond, &mutex.mMutex, &ts);
#endif // HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE
}
inline void Condition::signal() {
pthread_cond_signal(&mCond);
}
inline void Condition::broadcast() {
pthread_cond_broadcast(&mCond);
}
#endif // HAVE_PTHREADS
// ---------------------------------------------------------------------------
}; // namespace android
// ---------------------------------------------------------------------------
#endif // _LIBS_UTILS_CONDITON_H
|
