YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Copyright (c) 2011 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#include "yb/util/condition_variable.h"

#include <glog/logging.h>

#include "yb/util/errno.h"

#include "yb/util/monotime.h"

#include "yb/util/thread_restrictions.h"

using std::string;

namespace yb {

ConditionVariable::ConditionVariable(Mutex* user_lock)

    : user_mutex_(&user_lock->native_handle_)

#if !defined(NDEBUG)

    , user_lock_(user_lock)

#endif

{

  int rv = 0;

  // http://crbug.com/293736

  // NaCl doesn't support monotonic clock based absolute deadlines.

  // On older Android platform versions, it's supported through the

  // non-standard pthread_cond_timedwait_monotonic_np. Newer platform

  // versions have pthread_condattr_setclock.

  // Mac can use relative time deadlines.

#if !defined(__APPLE__) && !defined(OS_NACL) && \

      !(defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))

  pthread_condattr_t attrs;

  rv = pthread_condattr_init(&attrs);

  DCHECK_EQ(0, rv);

  pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC);

  rv = pthread_cond_init(&condition_, &attrs);

  pthread_condattr_destroy(&attrs);

#else

  rv = pthread_cond_init(&condition_, nullptr);

#endif

  DCHECK_EQ(0, rv) << ErrnoToString(rv);

}

ConditionVariable::~ConditionVariable() {

#if defined(OS_MACOSX)

  // This hack is necessary to avoid a fatal pthreads subsystem bug in the

  // Darwin kernel. https://codereview.chromium.org/1323293005/

  {

    Mutex lock;

    MutexLock l(lock);

    struct timespec ts;

    ts.tv_sec = 0;

    ts.tv_nsec = 1;

    pthread_cond_timedwait_relative_np(&condition_, &lock.native_handle_, &ts);

  }

#endif

  int rv = pthread_cond_destroy(&condition_);

  DCHECK_EQ(0, rv) << ErrnoToString(rv);

}

void ConditionVariable::Wait() const {

  ThreadRestrictions::AssertWaitAllowed();

#if !defined(NDEBUG)

  user_lock_->CheckHeldAndUnmark();

#endif

  int rv = pthread_cond_wait(&condition_, user_mutex_);

  DCHECK_EQ(0, rv) << ErrnoToString(rv);

#if !defined(NDEBUG)

  user_lock_->CheckUnheldAndMark();

#endif

}

bool ConditionVariable::WaitUntil(const MonoTime& wait_timeout_deadline) const {

  return TimedWait(wait_timeout_deadline - MonoTime::Now());

}

bool ConditionVariable::TimedWait(const MonoDelta& max_time) const {

  ThreadRestrictions::AssertWaitAllowed();

  // Negative delta means we've already timed out.

  int64 nsecs = max_time.ToNanoseconds();

  if (nsecs < 0) {

    return false;

  }

  struct timespec relative_time;

  max_time.ToTimeSpec(&relative_time);

#if !defined(NDEBUG)

  user_lock_->CheckHeldAndUnmark();

#endif

#if defined(__APPLE__)

  int rv = pthread_cond_timedwait_relative_np(

      &condition_, user_mutex_, &relative_time);

#else

  // The timeout argument to pthread_cond_timedwait is in absolute time.

  struct timespec absolute_time;

#if defined(OS_NACL)

  // See comment in constructor for why this is different in NaCl.

  struct timeval now;

  gettimeofday(&now, NULL);

  absolute_time.tv_sec = now.tv_sec;

  absolute_time.tv_nsec = now.tv_usec * MonoTime::kNanosecondsPerMicrosecond;

#else

  struct timespec now;

  clock_gettime(CLOCK_MONOTONIC, &now);

  absolute_time.tv_sec = now.tv_sec;

  absolute_time.tv_nsec = now.tv_nsec;

#endif

  absolute_time.tv_sec += relative_time.tv_sec;

  absolute_time.tv_nsec += relative_time.tv_nsec;

  absolute_time.tv_sec += absolute_time.tv_nsec / MonoTime::kNanosecondsPerSecond;

  absolute_time.tv_nsec %= MonoTime::kNanosecondsPerSecond;

  DCHECK_GE(absolute_time.tv_sec, now.tv_sec);  // Overflow paranoia

#if defined(OS_ANDROID) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC)

  int rv = pthread_cond_timedwait_monotonic_np(

      &condition_, user_mutex_, &absolute_time);

#else

  int rv = pthread_cond_timedwait(&condition_, user_mutex_, &absolute_time);

#endif  // OS_ANDROID && HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC

#endif  // __APPLE__

  DCHECK(rv == 0 || rv == ETIMEDOUT)

    << "unexpected pthread_cond_timedwait return value: " << rv;

#if !defined(NDEBUG)

  user_lock_->CheckUnheldAndMark();

#endif

  return rv == 0;

}

void ConditionVariable::Broadcast() {

  int rv = pthread_cond_broadcast(&condition_);

  DCHECK_EQ(0, rv) << ErrnoToString(rv);

}

void ConditionVariable::Signal() {

  int rv = pthread_cond_signal(&condition_);

  DCHECK_EQ(0, rv) << ErrnoToString(rv);

}

}  // namespace yb