base/synchronization/condition_variable_posix.cc

   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/synchronization/lock.h"
  11 #include "base/threading/thread_restrictions.h"
  12 #include "base/time/time.h"
  13
  14 namespace base {
  15
  16 ConditionVariable::ConditionVariable(Lock* user_lock)
  17     : user_mutex_(user_lock->lock_.native_handle())
  18 #if DCHECK_IS_ON()
  19     , user_lock_(user_lock)
  20 #endif
  21 {
  22   int rv = 0;
  23   // http://crbug.com/293736
  24   // NaCl doesn't support monotonic clock based absolute deadlines.
  25   // On older Android platform versions, it's supported through the
  26   // non-standard pthread_cond_timedwait_monotonic_np. Newer platform
  27   // versions have pthread_condattr_setclock.
  28   // Mac can use relative time deadlines.
  29 #if !defined(OS_MACOSX) && !defined(OS_NACL) && \
  30       !(defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
  31   pthread_condattr_t attrs;
  32   rv = pthread_condattr_init(&attrs);
  33   DCHECK_EQ(0, rv);
  34   pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
  35   rv = pthread_cond_init(&condition_, &attrs);
  36   pthread_condattr_destroy(&attrs);
  37 #else
  38   rv = pthread_cond_init(&condition_, NULL);
  39 #endif
  40   DCHECK_EQ(0, rv);
  41 }
  42
  43 ConditionVariable::~ConditionVariable() {
  44 #if defined(OS_MACOSX)
  45   // This hack is necessary to avoid a fatal pthreads subsystem bug in the
  46   // Darwin kernel. http://crbug.com/517681.
  47   {
  48     base::Lock lock;
  49     base::AutoLock l(lock);
  50     struct timespec ts;
  51     ts.tv_sec = 0;
  52     ts.tv_nsec = 1;
  53     pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(),
  54                                        &ts);
  55   }
  56 #endif
  57
  58   int rv = pthread_cond_destroy(&condition_);
  59   DCHECK_EQ(0, rv);
  60 }
  61
  62 void ConditionVariable::Wait() {
  63   base::ThreadRestrictions::AssertWaitAllowed();
  64 #if DCHECK_IS_ON()
  65   user_lock_->CheckHeldAndUnmark();
  66 #endif
  67   int rv = pthread_cond_wait(&condition_, user_mutex_);
  68   DCHECK_EQ(0, rv);
  69 #if DCHECK_IS_ON()
  70   user_lock_->CheckUnheldAndMark();
  71 #endif
  72 }
  73
  74 void ConditionVariable::TimedWait(const TimeDelta& max_time) {
  75   base::ThreadRestrictions::AssertWaitAllowed();
  76   int64 usecs = max_time.InMicroseconds();
  77   struct timespec relative_time;
  78   relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond;
  79   relative_time.tv_nsec =
  80       (usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond;
  81
  82 #if DCHECK_IS_ON()
  83   user_lock_->CheckHeldAndUnmark();
  84 #endif
  85
  86 #if defined(OS_MACOSX)
  87   int rv = pthread_cond_timedwait_relative_np(
  88       &condition_, user_mutex_, &relative_time);
  89 #else
  90   // The timeout argument to pthread_cond_timedwait is in absolute time.
  91   struct timespec absolute_time;
  92 #if defined(OS_NACL)
  93   // See comment in constructor for why this is different in NaCl.
  94   struct timeval now;
  95   gettimeofday(&now, NULL);
  96   absolute_time.tv_sec = now.tv_sec;
  97   absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond;
  98 #else
  99   struct timespec now;
 100   clock_gettime(CLOCK_MONOTONIC, &now);
 101   absolute_time.tv_sec = now.tv_sec;
 102   absolute_time.tv_nsec = now.tv_nsec;
 103 #endif
 104
 105   absolute_time.tv_sec += relative_time.tv_sec;
 106   absolute_time.tv_nsec += relative_time.tv_nsec;
 107   absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond;
 108   absolute_time.tv_nsec %= Time::kNanosecondsPerSecond;
 109   DCHECK_GE(absolute_time.tv_sec, now.tv_sec);  // Overflow paranoia
 110
 111 #if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
 112   int rv = pthread_cond_timedwait_monotonic_np(
 113       &condition_, user_mutex_, &absolute_time);
 114 #else
 115   int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
 116 #endif  // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
 117 #endif  // OS_MACOSX
 118
 119   DCHECK(rv == 0 || rv == ETIMEDOUT);
 120 #if DCHECK_IS_ON()
 121   user_lock_->CheckUnheldAndMark();
 122 #endif
 123 }
 124
 125 void ConditionVariable::Broadcast() {
 126   int rv = pthread_cond_broadcast(&condition_);
 127   DCHECK_EQ(0, rv);
 128 }
 129
 130 void ConditionVariable::Signal() {
 131   int rv = pthread_cond_signal(&condition_);
 132   DCHECK_EQ(0, rv);
 133 }
 134
 135 }  // namespace base