src/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   int rv = pthread_cond_destroy(&condition_);
  46   DCHECK_EQ(0, rv);
  47 }
  48
  49 void ConditionVariable::Wait() {
  50   base::ThreadRestrictions::AssertWaitAllowed();
  51 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  52   user_lock_->CheckHeldAndUnmark();
  53 #endif
  54   int rv = pthread_cond_wait(&condition_, user_mutex_);
  55   DCHECK_EQ(0, rv);
  56 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  57   user_lock_->CheckUnheldAndMark();
  58 #endif
  59 }
  60
  61 void ConditionVariable::TimedWait(const TimeDelta& max_time) {
  62   base::ThreadRestrictions::AssertWaitAllowed();
  63   int64 usecs = max_time.InMicroseconds();
  64   struct timespec relative_time;
  65   relative_time.tv_sec = usecs / Time::kMicrosecondsPerSecond;
  66   relative_time.tv_nsec =
  67       (usecs % Time::kMicrosecondsPerSecond) * Time::kNanosecondsPerMicrosecond;
  68
  69 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
  70   user_lock_->CheckHeldAndUnmark();
  71 #endif
  72
  73 #if defined(OS_MACOSX)
  74   int rv = pthread_cond_timedwait_relative_np(
  75       &condition_, user_mutex_, &relative_time);
  76 #else
  77   // The timeout argument to pthread_cond_timedwait is in absolute time.
  78   struct timespec absolute_time;
  79 #if defined(OS_NACL)
  80   // See comment in constructor for why this is different in NaCl.
  81   struct timeval now;
  82   gettimeofday(&now, NULL);
  83   absolute_time.tv_sec = now.tv_sec;
  84   absolute_time.tv_nsec = now.tv_usec * Time::kNanosecondsPerMicrosecond;
  85 #else
  86   struct timespec now;
  87   clock_gettime(CLOCK_MONOTONIC, &now);
  88   absolute_time.tv_sec = now.tv_sec;
  89   absolute_time.tv_nsec = now.tv_nsec;
  90 #endif
  91
  92   absolute_time.tv_sec += relative_time.tv_sec;
  93   absolute_time.tv_nsec += relative_time.tv_nsec;
  94   absolute_time.tv_sec += absolute_time.tv_nsec / Time::kNanosecondsPerSecond;
  95   absolute_time.tv_nsec %= Time::kNanosecondsPerSecond;
  96   DCHECK_GE(absolute_time.tv_sec, now.tv_sec);  // Overflow paranoia
  97
  98 #if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
  99   int rv = pthread_cond_timedwait_monotonic_np(
 100       &condition_, user_mutex_, &absolute_time);
 101 #else
 102   int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
 103 #endif  // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
 104 #endif  // OS_MACOSX
 105
 106   DCHECK(rv == 0 || rv == ETIMEDOUT);
 107 #if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
 108   user_lock_->CheckUnheldAndMark();
 109 #endif
 110 }
 111
 112 void ConditionVariable::Broadcast() {
 113   int rv = pthread_cond_broadcast(&condition_);
 114   DCHECK_EQ(0, rv);
 115 }
 116
 117 void ConditionVariable::Signal() {
 118   int rv = pthread_cond_signal(&condition_);
 119   DCHECK_EQ(0, rv);
 120 }
 121
 122 }  // namespace base