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/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
  17 ConditionVariable::ConditionVariable(Lock* user_lock)
  18     : user_mutex_(user_lock->lock_.native_handle())
  19 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  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   // On older Android platform versions, it's supported through the
  27   // non-standard pthread_cond_timedwait_monotonic_np. Newer platform
  28   // versions have pthread_condattr_setclock.
  29   // Mac can use relative time deadlines.
  30 #if !defined(OS_MACOSX) && !defined(OS_NACL) && \
  31       !(defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
  32   pthread_condattr_t attrs;
  33   rv = pthread_condattr_init(&attrs);
  34   DCHECK_EQ(0, rv);
  35   pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
  36   rv = pthread_cond_init(&condition_, &attrs);
  37   pthread_condattr_destroy(&attrs);
  38 #else
  39   rv = pthread_cond_init(&condition_, NULL);
  40 #endif
  41   DCHECK_EQ(0, rv);
  42 }
  43
  44 ConditionVariable::~ConditionVariable() {
  45 #if defined(OS_MACOSX)
  46   // This hack is necessary to avoid a fatal pthreads subsystem bug in the
  47   // Darwin kernel. http://crbug.com/517681.
  48   {
  49     base::Lock lock;
  50     base::AutoLock l(lock);
  51     struct timespec ts;
  52     ts.tv_sec = 0;
  53     ts.tv_nsec = 1;
  54     pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(),
  55                                        &ts);
  56   }
  57 #endif
  58
  59   int rv = pthread_cond_destroy(&condition_);
  60   DCHECK_EQ(0, rv);
  61 }
  62
  63 void ConditionVariable::Wait() {
  64   base::ThreadRestrictions::AssertWaitAllowed();
  65 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  66   user_lock_->CheckHeldAndUnmark();
  67 #endif
  68   int rv = pthread_cond_wait(&condition_, user_mutex_);
  69   DCHECK_EQ(0, rv);
  70 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  71   user_lock_->CheckUnheldAndMark();
  72 #endif
  73 }
  74
  75 void ConditionVariable::TimedWait(const TimeDelta& max_time) {
  76   base::ThreadRestrictions::AssertWaitAllowed();
  77   int64 usecs = max_time.InMicroseconds();
  78   struct timespec relative_time;
  79   relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond;
  80   relative_time.tv_nsec =
  81       (usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond;
  82
  83 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  84   user_lock_->CheckHeldAndUnmark();
  85 #endif
  86
  87 #if defined(OS_MACOSX)
  88   int rv = pthread_cond_timedwait_relative_np(
  89       &condition_, user_mutex_, &relative_time);
  90 #else
  91   // The timeout argument to pthread_cond_timedwait is in absolute time.
  92   struct timespec absolute_time;
  93 #if defined(OS_NACL)
  94   // See comment in constructor for why this is different in NaCl.
  95   struct timeval now;
  96   gettimeofday(&now, NULL);
  97   absolute_time.tv_sec = now.tv_sec;
  98   absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond;
  99 #else
 100   struct timespec now;
 101   clock_gettime(CLOCK_MONOTONIC, &now);
 102   absolute_time.tv_sec = now.tv_sec;
 103   absolute_time.tv_nsec = now.tv_nsec;
 104 #endif
 105
 106   absolute_time.tv_sec += relative_time.tv_sec;
 107   absolute_time.tv_nsec += relative_time.tv_nsec;
 108   absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond;
 109   absolute_time.tv_nsec %= Time::kNanosecondsPerSecond;
 110   DCHECK_GE(absolute_time.tv_sec, now.tv_sec);  // Overflow paranoia
 111
 112 #if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
 113   int rv = pthread_cond_timedwait_monotonic_np(
 114       &condition_, user_mutex_, &absolute_time);
 115 #else
 116   int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
 117 #endif  // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
 118 #endif  // OS_MACOSX
 119
 120   DCHECK(rv == 0 || rv == ETIMEDOUT);
 121 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
 122   user_lock_->CheckUnheldAndMark();
 123 #endif
 124 }
 125
 126 void ConditionVariable::Broadcast() {
 127   int rv = pthread_cond_broadcast(&condition_);
 128   DCHECK_EQ(0, rv);
 129 }
 130
 131 void ConditionVariable::Signal() {
 132   int rv = pthread_cond_signal(&condition_);
 133   DCHECK_EQ(0, rv);
 134 }
 135
 136 }  // namespace base