Merge "osi: Use atomic_exchange to protect is_joined"

#include "osi/include/thread.h"

#include <atomic>

#include <base/logging.h>

#include <errno.h>

#include <malloc.h>

#include "osi/include/semaphore.h"

struct thread_t {

  bool is_joined;

  std::atomic_bool is_joined{false};

  pthread_t pthread;

  pid_t tid;

  char name[THREAD_NAME_MAX + 1];

void thread_join(thread_t* thread) {

  CHECK(thread != NULL);

  // TODO(zachoverflow): use a compare and swap when ready

  if (!thread->is_joined) {

    thread->is_joined = true;

  if (!std::atomic_exchange(&thread->is_joined, true))

    pthread_join(thread->pthread, NULL);

}

}

bool thread_post(thread_t* thread, thread_fn func, void* context) {

  CHECK(thread != NULL);