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)
  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
  42 ConditionVariable::~ConditionVariable() {
  43   int rv = pthread_cond_destroy(&condition_);
  44   DCHECK_EQ(0, rv);
  45 }
  46
  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
  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
 110 void ConditionVariable::Broadcast() {
 111   int rv = pthread_cond_broadcast(&condition_);
 112   DCHECK_EQ(0, rv);
 113 }
 114
 115 void ConditionVariable::Signal() {
 116   int rv = pthread_cond_signal(&condition_);
 117   DCHECK_EQ(0, rv);
 118 }
 119
 120 }  // namespace base