Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


products/sources/formale Sprachen/Java/Openjdk/src/hotspot/os/bsd/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 3 kB

Quelle semaphore_bsd.cpp Sprache: C

/*
* Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#include "precompiled.hpp"
#include "semaphore_bsd.hpp"
#include "runtime/os.hpp"
#include "utilities/debug.hpp"

#include <semaphore.h>

#ifdef __APPLE__
// OS X doesn't support unnamed POSIX semaphores, so the implementation in os_posix.cpp can't be used.

static const char* sem_init_strerror(kern_return_t value) {
  switch (value) {
    case KERN_INVALID_ARGUMENT:  return "Invalid argument";
    case KERN_RESOURCE_SHORTAGE: return "Resource shortage";
    default:                     return "Unknown";
  }
}

OSXSemaphore::OSXSemaphore(uint value) {
  kern_return_t ret = semaphore_create(mach_task_self(), &_semaphore, SYNC_POLICY_FIFO, value);

  guarantee(ret == KERN_SUCCESS, "Failed to create semaphore: %s", sem_init_strerror(ret));
}

OSXSemaphore::~OSXSemaphore() {
  semaphore_destroy(mach_task_self(), _semaphore);
}

void OSXSemaphore::signal(uint count) {
  for (uint i = 0; i < count; i++) {
    kern_return_t ret = semaphore_signal(_semaphore);

    assert(ret == KERN_SUCCESS, "Failed to signal semaphore");
  }
}

void OSXSemaphore::wait() {
  kern_return_t ret;
  while ((ret = semaphore_wait(_semaphore)) == KERN_ABORTED) {
    // Semaphore was interrupted. Retry.
  }
  assert(ret == KERN_SUCCESS, "Failed to wait on semaphore");
}

bool OSXSemaphore::trywait() {
  return timedwait(0);
}

bool OSXSemaphore::timedwait(int64_t millis) {
  kern_return_t kr = KERN_ABORTED;

  // kernel semaphores take a relative timeout
  mach_timespec_t waitspec;
  int secs = millis / MILLIUNITS;
  int nsecs = millis_to_nanos(millis % MILLIUNITS);
  waitspec.tv_sec = secs;
  waitspec.tv_nsec = nsecs;

  int64_t starttime = os::javaTimeNanos();

  kr = semaphore_timedwait(_semaphore, waitspec);
  while (kr == KERN_ABORTED) {
    // reduce the timeout and try again
    int64_t totalwait = millis_to_nanos(millis);
    int64_t current = os::javaTimeNanos();
    int64_t passedtime = current - starttime;

    if (passedtime >= totalwait) {
      waitspec.tv_sec = 0;
      waitspec.tv_nsec = 0;
    } else {
      int64_t waittime = totalwait - (current - starttime);
      waitspec.tv_sec = waittime / NANOSECS_PER_SEC;
      waitspec.tv_nsec = waittime % NANOSECS_PER_SEC;
    }

    kr = semaphore_timedwait(_semaphore, waitspec);
  }

  return kr == KERN_SUCCESS;
}
#endif // __APPLE__

quality74%

¤ Dauer der Verarbeitung: 0.10 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.