// Copyright (c) 2006-2008 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.

#include "base/platform_thread.h"

#include <errno.h>
#include <sched.h>

#if defined(OS_MACOSX)
#include <mach/mach.h>
#elif defined(OS_LINUX)
#include <sys/syscall.h>
#include <unistd.h>
#endif

#if defined(OS_MACOSX)
namespace base {
void InitThreading();
}  // namespace
#endif

static void* ThreadFunc(void* closure) {
  PlatformThread::Delegate* delegate =
      static_cast<PlatformThread::Delegate*>(closure);
  delegate->ThreadMain();
  return NULL;
}

// static
PlatformThreadId PlatformThread::CurrentId() {
  // Pthreads doesn't have the concept of a thread ID, so we have to reach down
  // into the kernel.
#if defined(OS_MACOSX)
  return mach_thread_self();
#elif defined (__OpenBSD__)
  // TODO(BSD): find a better thread ID
  return (intptr_t)(pthread_self());
#elif defined(OS_LINUX)
  return syscall(__NR_gettid);
#endif
}

// static
void PlatformThread::YieldCurrentThread() {
  sched_yield();
}

// static
void PlatformThread::Sleep(int duration_ms) {
  struct timespec sleep_time, remaining;

  // Contains the portion of duration_ms >= 1 sec.
  sleep_time.tv_sec = duration_ms / 1000;
  duration_ms -= sleep_time.tv_sec * 1000;

  // Contains the portion of duration_ms < 1 sec.
  sleep_time.tv_nsec = duration_ms * 1000 * 1000;  // nanoseconds.

  while (nanosleep(&sleep_time, &remaining) == -1 && errno == EINTR)
    sleep_time = remaining;
}

// static
void PlatformThread::SetName(const char* name) {
  // The POSIX standard does not provide for naming threads, and neither Linux
  // nor Mac OS X (our two POSIX targets) provide any non-portable way of doing
  // it either. (Some BSDs provide pthread_set_name_np but that isn't much of a
  // consolation prize.)
  // TODO(darin): decide whether stuffing the name in TLS or other in-memory
  // structure would be useful for debugging or not.
}

namespace {

bool CreateThread(size_t stack_size, bool joinable,
                  PlatformThread::Delegate* delegate,
                  PlatformThreadHandle* thread_handle) {
#if defined(OS_MACOSX)
  base::InitThreading();
#endif  // OS_MACOSX

  bool success = false;
  pthread_attr_t attributes;
  pthread_attr_init(&attributes);

  // Pthreads are joinable by default, so only specify the detached attribute if
  // the thread should be non-joinable.
  if (!joinable) {
    pthread_attr_setdetachstate(&attributes, PTHREAD_CREATE_DETACHED);
  }

  if (stack_size > 0)
    pthread_attr_setstacksize(&attributes, stack_size);

  success = !pthread_create(thread_handle, &attributes, ThreadFunc, delegate);

  pthread_attr_destroy(&attributes);
  return success;
}

}  // anonymous namespace

// static
bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
                            PlatformThreadHandle* thread_handle) {
  return CreateThread(stack_size, true /* joinable thread */,
                      delegate, thread_handle);
}

// static
bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
  PlatformThreadHandle unused;

  bool result = CreateThread(stack_size, false /* non-joinable thread */,
                             delegate, &unused);
  return result;
}

// static
void PlatformThread::Join(PlatformThreadHandle thread_handle) {
  pthread_join(thread_handle, NULL);
}
