/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include "uv.h"

#include "task.h"

#include <stdio.h>

#include <stdlib.h>

static uv_cond_t condvar;

static uv_mutex_t mutex;

static uv_rwlock_t rwlock;

static int step;

/* The mutex and rwlock tests are really poor.

 * They're very basic sanity checks and nothing more.

 * Apologies if that rhymes.

 */

TEST_IMPL(thread_mutex) {

  uv_mutex_t mutex;

  int r;

  r = uv_mutex_init(&mutex);

  ASSERT(r == 0);

  uv_mutex_lock(&mutex);

  uv_mutex_unlock(&mutex);

  uv_mutex_destroy(&mutex);

  return 0;

}

TEST_IMPL(thread_mutex_recursive) {

  uv_mutex_t mutex;

  int r;

  r = uv_mutex_init_recursive(&mutex);

  ASSERT(r == 0);

  uv_mutex_lock(&mutex);

  uv_mutex_lock(&mutex);

  ASSERT(0 == uv_mutex_trylock(&mutex));

  uv_mutex_unlock(&mutex);

  uv_mutex_unlock(&mutex);

  uv_mutex_unlock(&mutex);

  uv_mutex_destroy(&mutex);

  return 0;

}

TEST_IMPL(thread_rwlock) {

  uv_rwlock_t rwlock;

  int r;

  r = uv_rwlock_init(&rwlock);

  ASSERT(r == 0);

  uv_rwlock_rdlock(&rwlock);

  uv_rwlock_rdunlock(&rwlock);

  uv_rwlock_wrlock(&rwlock);

  uv_rwlock_wrunlock(&rwlock);

  uv_rwlock_destroy(&rwlock);

  return 0;

}

/* Call when holding |mutex|. */

static void synchronize_nowait(void) {

  step += 1;

  uv_cond_signal(&condvar);

}

/* Call when holding |mutex|. */

static void synchronize(void) {

  int current;

  synchronize_nowait();

  /* Wait for the other thread.  Guard against spurious wakeups. */

  for (current = step; current == step; uv_cond_wait(&condvar, &mutex));

  ASSERT(step == current + 1);

}

static void thread_rwlock_trylock_peer(void* unused) {

  (void) &unused;

  uv_mutex_lock(&mutex);

  /* Write lock held by other thread. */

  ASSERT(UV_EBUSY == uv_rwlock_tryrdlock(&rwlock));

  ASSERT(UV_EBUSY == uv_rwlock_trywrlock(&rwlock));

  synchronize();

  /* Read lock held by other thread. */

  ASSERT(0 == uv_rwlock_tryrdlock(&rwlock));

  uv_rwlock_rdunlock(&rwlock);

  ASSERT(UV_EBUSY == uv_rwlock_trywrlock(&rwlock));

  synchronize();

  /* Acquire write lock. */

  ASSERT(0 == uv_rwlock_trywrlock(&rwlock));

  synchronize();

  /* Release write lock and acquire read lock. */

  uv_rwlock_wrunlock(&rwlock);

  ASSERT(0 == uv_rwlock_tryrdlock(&rwlock));

  synchronize();

  uv_rwlock_rdunlock(&rwlock);

  synchronize_nowait();  /* Signal main thread we're going away. */

  uv_mutex_unlock(&mutex);

}

TEST_IMPL(thread_rwlock_trylock) {

  uv_thread_t thread;

  ASSERT(0 == uv_cond_init(&condvar));

  ASSERT(0 == uv_mutex_init(&mutex));

  ASSERT(0 == uv_rwlock_init(&rwlock));

  uv_mutex_lock(&mutex);

  ASSERT(0 == uv_thread_create(&thread, thread_rwlock_trylock_peer, NULL));

  /* Hold write lock. */

  ASSERT(0 == uv_rwlock_trywrlock(&rwlock));

  synchronize();  /* Releases the mutex to the other thread. */

  /* Release write lock and acquire read lock.  Pthreads doesn't support

   * the notion of upgrading or downgrading rwlocks, so neither do we.

   */

  uv_rwlock_wrunlock(&rwlock);

  ASSERT(0 == uv_rwlock_tryrdlock(&rwlock));

  synchronize();

  /* Release read lock. */

  uv_rwlock_rdunlock(&rwlock);

  synchronize();

  /* Write lock held by other thread. */

  ASSERT(UV_EBUSY == uv_rwlock_tryrdlock(&rwlock));

  ASSERT(UV_EBUSY == uv_rwlock_trywrlock(&rwlock));

  synchronize();

  /* Read lock held by other thread. */

  ASSERT(0 == uv_rwlock_tryrdlock(&rwlock));

  uv_rwlock_rdunlock(&rwlock);

  ASSERT(UV_EBUSY == uv_rwlock_trywrlock(&rwlock));

  synchronize();

  ASSERT(0 == uv_thread_join(&thread));

  uv_rwlock_destroy(&rwlock);

  uv_mutex_unlock(&mutex);

  uv_mutex_destroy(&mutex);

  uv_cond_destroy(&condvar);

  return 0;

}