ipc/chromium/src/base/condition_variable_posix.cc

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style license that can be
   5 // found in the LICENSE file.
   6
   7 #include "base/condition_variable.h"
   8
   9 #include <errno.h>
  10 #include <stdint.h>
  11 #include <sys/time.h>
  12
  13 #include "base/lock.h"
  14 #include "base/logging.h"
  15 #include "base/time.h"
  16
  17 ConditionVariable::ConditionVariable(Lock* user_lock)
  18     : user_mutex_(user_lock->lock_.native_handle()) {
  19   int rv = 0;
  20   // http://crbug.com/293736
  21   // On older Android platform versions, monotonic clock based absolute
  22   // deadlines are supported through the non-standard
  23   // pthread_cond_timedwait_monotonic_np. Newer platform versions have
  24   // pthread_condattr_setclock.
  25   // Mac can use relative time deadlines.
  26 #if !defined(XP_DARWIN) && \
  27     !(defined(ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
  28   pthread_condattr_t attrs;
  29   rv = pthread_condattr_init(&attrs);
  30   DCHECK_EQ(0, rv);
  31   pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);
  32   rv = pthread_cond_init(&condition_, &attrs);
  33   pthread_condattr_destroy(&attrs);
  34 #else
  35   rv = pthread_cond_init(&condition_, NULL);
  36 #endif
  37   DCHECK_EQ(0, rv);
  38 }
  39
  40 ConditionVariable::~ConditionVariable() {
  41 #if defined(XP_DARWIN)
  42   // This hack is necessary to avoid a fatal pthreads subsystem bug in the
  43   // Darwin kernel. http://crbug.com/517681.
  44   {
  45     Lock lock;
  46     AutoLock l(lock);
  47     struct timespec ts;
  48     ts.tv_sec = 0;
  49     ts.tv_nsec = 1;
  50     pthread_cond_timedwait_relative_np(&condition_, lock.lock_.native_handle(),
  51                                        &ts);
  52   }
  53 #endif
  54
  55   int rv = pthread_cond_destroy(&condition_);
  56   DCHECK_EQ(0, rv);
  57 }
  58
  59 void ConditionVariable::Wait() {
  60   int rv = pthread_cond_wait(&condition_, user_mutex_);
  61   DCHECK_EQ(0, rv);
  62 }
  63
  64 void ConditionVariable::TimedWait(const base::TimeDelta& max_time) {
  65   int64_t usecs = max_time.InMicroseconds();
  66   struct timespec relative_time;
  67   relative_time.tv_sec = usecs / base::Time::kMicrosecondsPerSecond;
  68   relative_time.tv_nsec = (usecs % base::Time::kMicrosecondsPerSecond) *
  69                           base::Time::kNanosecondsPerMicrosecond;
  70
  71 #if defined(XP_DARWIN)
  72   int rv = pthread_cond_timedwait_relative_np(&condition_, user_mutex_,
  73                                               &relative_time);
  74 #else
  75   // The timeout argument to pthread_cond_timedwait is in absolute time.
  76   struct timespec absolute_time;
  77   struct timespec now;
  78   clock_gettime(CLOCK_MONOTONIC, &now);
  79   absolute_time.tv_sec = now.tv_sec;
  80   absolute_time.tv_nsec = now.tv_nsec;
  81
  82   absolute_time.tv_sec += relative_time.tv_sec;
  83   absolute_time.tv_nsec += relative_time.tv_nsec;
  84   absolute_time.tv_sec +=
  85       absolute_time.tv_nsec / base::Time::kNanosecondsPerSecond;
  86   absolute_time.tv_nsec %= base::Time::kNanosecondsPerSecond;
  87   DCHECK_GE(absolute_time.tv_sec, now.tv_sec);  // Overflow paranoia
  88
  89 #  if defined(ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)
  90   int rv = pthread_cond_timedwait_monotonic_np(&condition_, user_mutex_,
  91                                                &absolute_time);
  92 #  else
  93   int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);
  94 #  endif  // ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC
  95 #endif    // XP_DARWIN
  96
  97   // On failure, we only expect the CV to timeout. Any other error value means
  98   // that we've unexpectedly woken up.
  99   DCHECK(rv == 0 || rv == ETIMEDOUT);
 100 }
 101
 102 void ConditionVariable::Broadcast() {
 103   int rv = pthread_cond_broadcast(&condition_);
 104   DCHECK_EQ(0, rv);
 105 }
 106
 107 void ConditionVariable::Signal() {
 108   int rv = pthread_cond_signal(&condition_);
 109   DCHECK_EQ(0, rv);
 110 }