1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/synchronization/condition_variable.h"
6
7 #include <errno.h>
8 #include <sys/time.h>
9
10 #include "base/logging.h"
11 #include "base/synchronization/lock.h"
12 #include "base/threading/thread_restrictions.h"
13 #include "base/time/time.h"
14
15 namespace base {
16
ConditionVariable(Lock * user_lock)17 ConditionVariable::ConditionVariable(Lock* user_lock)
18 : user_mutex_(user_lock->lock_.native_handle())
19 #if !defined(NDEBUG)
20 , user_lock_(user_lock)
21 #endif
22 {
23 int rv = 0;
24 // http://crbug.com/293736
25 // NaCl doesn't support monotonic clock based absolute deadlines.
26 // Android supports it through the non-standard
27 // pthread_cond_timedwait_monotonic_np.
28 // Mac can use relative time deadlines.
29 #if !defined(OS_MACOSX) && !defined(OS_NACL) && !defined(OS_ANDROID)
30 pthread_condattr_t attrs;
31 rv = pthread_condattr_init(&attrs);
32 DCHECK_EQ(0, rv);
33 pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
34 rv = pthread_cond_init(&condition_, &attrs);
35 pthread_condattr_destroy(&attrs);
36 #else
37 rv = pthread_cond_init(&condition_, NULL);
38 #endif
39 DCHECK_EQ(0, rv);
40 }
41
~ConditionVariable()42 ConditionVariable::~ConditionVariable() {
43 int rv = pthread_cond_destroy(&condition_);
44 DCHECK_EQ(0, rv);
45 }
46
Wait()47 void ConditionVariable::Wait() {
48 base::ThreadRestrictions::AssertWaitAllowed();
49 #if !defined(NDEBUG)
50 user_lock_->CheckHeldAndUnmark();
51 #endif
52 int rv = pthread_cond_wait(&condition_, user_mutex_);
53 DCHECK_EQ(0, rv);
54 #if !defined(NDEBUG)
55 user_lock_->CheckUnheldAndMark();
56 #endif
57 }
58
TimedWait(const TimeDelta & max_time)59 void ConditionVariable::TimedWait(const TimeDelta& max_time) {
60 base::ThreadRestrictions::AssertWaitAllowed();
61 int64 usecs = max_time.InMicroseconds();
62 struct timespec relative_time;
63 relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond;
64 relative_time.tv_nsec =
65 (usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond;
66
67 #if !defined(NDEBUG)
68 user_lock_->CheckHeldAndUnmark();
69 #endif
70
71 #if defined(OS_MACOSX)
72 int rv = pthread_cond_timedwait_relative_np(
73 &condition_, user_mutex_, &relative_time);
74 #else
75 // The timeout argument to pthread_cond_timedwait is in absolute time.
76 struct timespec absolute_time;
77 #if defined(OS_NACL)
78 // See comment in constructor for why this is different in NaCl.
79 struct timeval now;
80 gettimeofday(&now, NULL);
81 absolute_time.tv_sec = now.tv_sec;
82 absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond;
83 #else
84 struct timespec now;
85 clock_gettime(CLOCK_MONOTONIC, &now);
86 absolute_time.tv_sec = now.tv_sec;
87 absolute_time.tv_nsec = now.tv_nsec;
88 #endif
89
90 absolute_time.tv_sec += relative_time.tv_sec;
91 absolute_time.tv_nsec += relative_time.tv_nsec;
92 absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond;
93 absolute_time.tv_nsec %= Time::kNanosecondsPerSecond;
94 DCHECK_GE(absolute_time.tv_sec, now.tv_sec); // Overflow paranoia
95
96 #if defined(OS_ANDROID)
97 int rv = pthread_cond_timedwait_monotonic_np(
98 &condition_, user_mutex_, &absolute_time);
99 #else
100 int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
101 #endif // OS_ANDROID
102 #endif // OS_MACOSX
103
104 DCHECK(rv == 0 || rv == ETIMEDOUT);
105 #if !defined(NDEBUG)
106 user_lock_->CheckUnheldAndMark();
107 #endif
108 }
109
Broadcast()110 void ConditionVariable::Broadcast() {
111 int rv = pthread_cond_broadcast(&condition_);
112 DCHECK_EQ(0, rv);
113 }
114
Signal()115 void ConditionVariable::Signal() {
116 int rv = pthread_cond_signal(&condition_);
117 DCHECK_EQ(0, rv);
118 }
119
120 } // namespace base
121