deskflow/src/lib/mt/CondVar.cpp

/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2012-2016 Symless Ltd.
 * Copyright (C) 2002 Chris Schoeneman
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "mt/CondVar.h"
#include "arch/Arch.h"
#include "base/Stopwatch.h"

//
// CondVarBase
//

CondVarBase::CondVarBase(Mutex *mutex) : m_mutex(mutex) {
  assert(m_mutex != NULL);
  m_cond = ARCH->newCondVar();
}

CondVarBase::~CondVarBase() { ARCH->closeCondVar(m_cond); }

void CondVarBase::lock() const { m_mutex->lock(); }

void CondVarBase::unlock() const { m_mutex->unlock(); }

void CondVarBase::signal() { ARCH->signalCondVar(m_cond); }

void CondVarBase::broadcast() { ARCH->broadcastCondVar(m_cond); }

bool CondVarBase::wait(Stopwatch &timer, double timeout) const {
  double remain = timeout - timer.getTime();
  // Some ARCH wait()s return prematurely, retry until really timed out
  // In particular, ArchMultithreadPosix::waitCondVar() returns every 100ms
  do {
    // Always call wait at least once, even if remain is 0, to give
    // other thread a chance to grab the mutex to avoid deadlocks on
    // busy waiting.
    if (remain < 0.0)
      remain = 0.0;
    if (wait(remain))
      return true;
    remain = timeout - timer.getTime();
  } while (remain >= 0.0);
  return false;
}

bool CondVarBase::wait(double timeout) const {
  return ARCH->waitCondVar(m_cond, m_mutex->m_mutex, timeout);
}

Mutex *CondVarBase::getMutex() const { return m_mutex; }