// Copyright 2008, Google Inc.
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//
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// modification, are permitted provided that the following conditions are
// met:
//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#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

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

// static
int 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(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(int thread_id, const char* name) {
  // TODO(darin): implement me!
}

// static
bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
                            PlatformThreadHandle* thread_handle) {
  bool success = false;
  pthread_attr_t attributes;
  pthread_attr_init(&attributes);

  // Pthreads are joinable by default, so we don't need to specify any special
  // attributes to be able to call pthread_join later.
  
  if (stack_size > 0)
    pthread_attr_setstacksize(&attributes, stack_size);

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

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