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 <stdint.h> 9 #include <sys/time.h> 10 11 #include "base/synchronization/lock.h" 12 #include "base/threading/thread_restrictions.h" 13 #include "base/time/time.h" 14 #include "build/build_config.h" 15 16 namespace base { 17 18 ConditionVariable::ConditionVariable(Lock* user_lock) 19 : user_mutex_(user_lock->lock_.native_handle()) 20 #if DCHECK_IS_ON() 21 , user_lock_(user_lock) 22 #endif 23 { 24 int rv = 0; 25 // http://crbug.com/293736 26 // NaCl doesn't support monotonic clock based absolute deadlines. 27 // On older Android platform versions, it's supported through the 28 // non-standard pthread_cond_timedwait_monotonic_np. Newer platform 29 // versions have pthread_condattr_setclock. 30 // Mac can use relative time deadlines. 31 #if !defined(OS_MACOSX) && !defined(OS_NACL) && \ 32 !(defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)) 33 pthread_condattr_t attrs; 34 rv = pthread_condattr_init(&attrs); 35 DCHECK_EQ(0, rv); 36 pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC); 37 rv = pthread_cond_init(&condition_, &attrs); 38 pthread_condattr_destroy(&attrs); 39 #else 40 rv = pthread_cond_init(&condition_, NULL); 41 #endif 42 DCHECK_EQ(0, rv); 43 } 44 45 ConditionVariable::~ConditionVariable() { 46 #if defined(OS_MACOSX) 47 // This hack is necessary to avoid a fatal pthreads subsystem bug in the 48 // Darwin kernel. http://crbug.com/517681. 49 { 50 base::Lock lock; 51 base::AutoLock l(lock); 52 struct timespec ts; 53 ts.tv_sec = 0; 54 ts.tv_nsec = 1; 55 pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(), 56 &ts); 57 } 58 #endif 59 60 int rv = pthread_cond_destroy(&condition_); 61 DCHECK_EQ(0, rv); 62 } 63 64 void ConditionVariable::Wait() { 65 base::ThreadRestrictions::AssertWaitAllowed(); 66 #if DCHECK_IS_ON() 67 user_lock_->CheckHeldAndUnmark(); 68 #endif 69 int rv = pthread_cond_wait(&condition_, user_mutex_); 70 DCHECK_EQ(0, rv); 71 #if DCHECK_IS_ON() 72 user_lock_->CheckUnheldAndMark(); 73 #endif 74 } 75 76 void ConditionVariable::TimedWait(const TimeDelta& max_time) { 77 base::ThreadRestrictions::AssertWaitAllowed(); 78 int64_t usecs = max_time.InMicroseconds(); 79 struct timespec relative_time; 80 relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond; 81 relative_time.tv_nsec = 82 (usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond; 83 84 #if DCHECK_IS_ON() 85 user_lock_->CheckHeldAndUnmark(); 86 #endif 87 88 #if defined(OS_MACOSX) 89 int rv = pthread_cond_timedwait_relative_np( 90 &condition_, user_mutex_, &relative_time); 91 #else 92 // The timeout argument to pthread_cond_timedwait is in absolute time. 93 struct timespec absolute_time; 94 #if defined(OS_NACL) 95 // See comment in constructor for why this is different in NaCl. 96 struct timeval now; 97 gettimeofday(&now, NULL); 98 absolute_time.tv_sec = now.tv_sec; 99 absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond; 100 #else 101 struct timespec now; 102 clock_gettime(CLOCK_MONOTONIC, &now); 103 absolute_time.tv_sec = now.tv_sec; 104 absolute_time.tv_nsec = now.tv_nsec; 105 #endif 106 107 absolute_time.tv_sec += relative_time.tv_sec; 108 absolute_time.tv_nsec += relative_time.tv_nsec; 109 absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond; 110 absolute_time.tv_nsec %= Time::kNanosecondsPerSecond; 111 DCHECK_GE(absolute_time.tv_sec, now.tv_sec); // Overflow paranoia 112 113 #if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC) 114 int rv = pthread_cond_timedwait_monotonic_np( 115 &condition_, user_mutex_, &absolute_time); 116 #else 117 int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time); 118 #endif // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC 119 #endif // OS_MACOSX 120 121 DCHECK(rv == 0 || rv == ETIMEDOUT); 122 #if DCHECK_IS_ON() 123 user_lock_->CheckUnheldAndMark(); 124 #endif 125 } 126 127 void ConditionVariable::Broadcast() { 128 int rv = pthread_cond_broadcast(&condition_); 129 DCHECK_EQ(0, rv); 130 } 131 132 void ConditionVariable::Signal() { 133 int rv = pthread_cond_signal(&condition_); 134 DCHECK_EQ(0, rv); 135 } 136 137 } // namespace base 138
