/* 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 <assert.h>

#include <limits.h>

#include <stdlib.h>

#if defined(__MINGW64_VERSION_MAJOR)

/* MemoryBarrier expands to __mm_mfence in some cases (x86+sse2), which may

 * require this header in some versions of mingw64. */

#include <intrin.h>

#endif

#include "uv.h"

#include "internal.h"

static void uv__once_inner(uv_once_t* guard, void (*callback)(void)) {

  DWORD result;

  HANDLE existing_event, created_event;

  created_event = CreateEvent(NULL, 1, 0, NULL);

  if (created_event == 0) {

    /* Could fail in a low-memory situation? */

    uv_fatal_error(GetLastError(), "CreateEvent");

  }

  existing_event = InterlockedCompareExchangePointer(&guard->event,

                                                     created_event,

                                                     NULL);

  if (existing_event == NULL) {

    /* We won the race */

    callback();

    result = SetEvent(created_event);

    assert(result);

    guard->ran = 1;

  } else {

    /* We lost the race. Destroy the event we created and wait for the existing

     * one to become signaled. */

    CloseHandle(created_event);

    result = WaitForSingleObject(existing_event, INFINITE);

    assert(result == WAIT_OBJECT_0);

  }

}

void uv_once(uv_once_t* guard, void (*callback)(void)) {

  /* Fast case - avoid WaitForSingleObject. */

  if (guard->ran) {

    return;

  }

  uv__once_inner(guard, callback);

}

/* Verify that uv_thread_t can be stored in a TLS slot. */

STATIC_ASSERT(sizeof(uv_thread_t) <= sizeof(void*));

static uv_key_t uv__current_thread_key;

static uv_once_t uv__current_thread_init_guard = UV_ONCE_INIT;

static void uv__init_current_thread_key(void) {

  if (uv_key_create(&uv__current_thread_key))

    abort();

}

struct thread_ctx {

  void (*entry)(void* arg);

  void* arg;

  uv_thread_t self;

};

static UINT __stdcall uv__thread_start(void* arg) {

  struct thread_ctx *ctx_p;

  struct thread_ctx ctx;

  ctx_p = arg;

  ctx = *ctx_p;

  uv__free(ctx_p);

  uv_once(&uv__current_thread_init_guard, uv__init_current_thread_key);

  uv_key_set(&uv__current_thread_key, (void*) ctx.self);

  ctx.entry(ctx.arg);

  return 0;

}

int uv_thread_create(uv_thread_t *tid, void (*entry)(void *arg), void *arg) {

  uv_thread_options_t params;

  params.flags = UV_THREAD_NO_FLAGS;

  return uv_thread_create_ex(tid, &params, entry, arg);

}

int uv_thread_create_ex(uv_thread_t* tid,

                        const uv_thread_options_t* params,

                        void (*entry)(void *arg),

                        void *arg) {

  struct thread_ctx* ctx;

  int err;

  HANDLE thread;

  SYSTEM_INFO sysinfo;

  size_t stack_size;

  size_t pagesize;

  stack_size =

      params->flags & UV_THREAD_HAS_STACK_SIZE ? params->stack_size : 0;

  if (stack_size != 0) {

    GetNativeSystemInfo(&sysinfo);

    pagesize = (size_t)sysinfo.dwPageSize;

    /* Round up to the nearest page boundary. */

    stack_size = (stack_size + pagesize - 1) &~ (pagesize - 1);

    if ((unsigned)stack_size != stack_size)

      return UV_EINVAL;

  }

  ctx = uv__malloc(sizeof(*ctx));

  if (ctx == NULL)

    return UV_ENOMEM;

  ctx->entry = entry;

  ctx->arg = arg;

  /* Create the thread in suspended state so we have a chance to pass

   * its own creation handle to it */

  thread = (HANDLE) _beginthreadex(NULL,

                                   (unsigned)stack_size,

                                   uv__thread_start,

                                   ctx,

                                   CREATE_SUSPENDED,

                                   NULL);

  if (thread == NULL) {

    err = errno;

    uv__free(ctx);

  } else {

    err = 0;

    *tid = thread;

    ctx->self = thread;

    ResumeThread(thread);

  }

  switch (err) {

    case 0:

      return 0;

    case EACCES:

      return UV_EACCES;

    case EAGAIN:

      return UV_EAGAIN;

    case EINVAL:

      return UV_EINVAL;

  }

  return UV_EIO;

}

uv_thread_t uv_thread_self(void) {

  uv_once(&uv__current_thread_init_guard, uv__init_current_thread_key);

  return (uv_thread_t) uv_key_get(&uv__current_thread_key);

}

int uv_thread_join(uv_thread_t *tid) {

  if (WaitForSingleObject(*tid, INFINITE))

    return uv_translate_sys_error(GetLastError());

  else {

    CloseHandle(*tid);

    *tid = 0;

    MemoryBarrier();  /* For feature parity with pthread_join(). */

    return 0;

  }

}

int uv_thread_equal(const uv_thread_t* t1, const uv_thread_t* t2) {

  return *t1 == *t2;

}

int uv_mutex_init(uv_mutex_t* mutex) {

  InitializeCriticalSection(mutex);

  return 0;

}

int uv_mutex_init_recursive(uv_mutex_t* mutex) {

  return uv_mutex_init(mutex);

}

void uv_mutex_destroy(uv_mutex_t* mutex) {

  DeleteCriticalSection(mutex);

}

void uv_mutex_lock(uv_mutex_t* mutex) {

  EnterCriticalSection(mutex);

}

int uv_mutex_trylock(uv_mutex_t* mutex) {

  if (TryEnterCriticalSection(mutex))

    return 0;

  else

    return UV_EBUSY;

}

void uv_mutex_unlock(uv_mutex_t* mutex) {

  LeaveCriticalSection(mutex);

}

int uv_rwlock_init(uv_rwlock_t* rwlock) {

  /* Initialize the semaphore that acts as the write lock. */

  HANDLE handle = CreateSemaphoreW(NULL, 1, 1, NULL);

  if (handle == NULL)

    return uv_translate_sys_error(GetLastError());

  rwlock->state_.write_semaphore_ = handle;

  /* Initialize the critical section protecting the reader count. */

  InitializeCriticalSection(&rwlock->state_.num_readers_lock_);

  /* Initialize the reader count. */

  rwlock->state_.num_readers_ = 0;

  return 0;

}

void uv_rwlock_destroy(uv_rwlock_t* rwlock) {

  DeleteCriticalSection(&rwlock->state_.num_readers_lock_);

  CloseHandle(rwlock->state_.write_semaphore_);

}

void uv_rwlock_rdlock(uv_rwlock_t* rwlock) {

  /* Acquire the lock that protects the reader count. */

  EnterCriticalSection(&rwlock->state_.num_readers_lock_);

  /* Increase the reader count, and lock for write if this is the first

   * reader.

   */

  if (++rwlock->state_.num_readers_ == 1) {

    DWORD r = WaitForSingleObject(rwlock->state_.write_semaphore_, INFINITE);

    if (r != WAIT_OBJECT_0)

      uv_fatal_error(GetLastError(), "WaitForSingleObject");

  }

  /* Release the lock that protects the reader count. */

  LeaveCriticalSection(&rwlock->state_.num_readers_lock_);

}

int uv_rwlock_tryrdlock(uv_rwlock_t* rwlock) {

  int err;

  if (!TryEnterCriticalSection(&rwlock->state_.num_readers_lock_))

    return UV_EBUSY;

  err = 0;

  if (rwlock->state_.num_readers_ == 0) {

    /* Currently there are no other readers, which means that the write lock

     * needs to be acquired.

     */

    DWORD r = WaitForSingleObject(rwlock->state_.write_semaphore_, 0);

    if (r == WAIT_OBJECT_0)

      rwlock->state_.num_readers_++;

    else if (r == WAIT_TIMEOUT)

      err = UV_EBUSY;

    else if (r == WAIT_FAILED)

      uv_fatal_error(GetLastError(), "WaitForSingleObject");

  } else {

    /* The write lock has already been acquired because there are other

     * active readers.

     */

    rwlock->state_.num_readers_++;

  }

  LeaveCriticalSection(&rwlock->state_.num_readers_lock_);

  return err;

}

void uv_rwlock_rdunlock(uv_rwlock_t* rwlock) {

  EnterCriticalSection(&rwlock->state_.num_readers_lock_);

  if (--rwlock->state_.num_readers_ == 0) {

    if (!ReleaseSemaphore(rwlock->state_.write_semaphore_, 1, NULL))

      uv_fatal_error(GetLastError(), "ReleaseSemaphore");

  }

  LeaveCriticalSection(&rwlock->state_.num_readers_lock_);

}

void uv_rwlock_wrlock(uv_rwlock_t* rwlock) {

  DWORD r = WaitForSingleObject(rwlock->state_.write_semaphore_, INFINITE);

  if (r != WAIT_OBJECT_0)

    uv_fatal_error(GetLastError(), "WaitForSingleObject");

}

int uv_rwlock_trywrlock(uv_rwlock_t* rwlock) {

  DWORD r = WaitForSingleObject(rwlock->state_.write_semaphore_, 0);

  if (r == WAIT_OBJECT_0)

    return 0;

  else if (r == WAIT_TIMEOUT)

    return UV_EBUSY;

  else

    uv_fatal_error(GetLastError(), "WaitForSingleObject");

}

void uv_rwlock_wrunlock(uv_rwlock_t* rwlock) {

  if (!ReleaseSemaphore(rwlock->state_.write_semaphore_, 1, NULL))

    uv_fatal_error(GetLastError(), "ReleaseSemaphore");

}

int uv_sem_init(uv_sem_t* sem, unsigned int value) {

  *sem = CreateSemaphore(NULL, value, INT_MAX, NULL);

  if (*sem == NULL)

    return uv_translate_sys_error(GetLastError());

  else

    return 0;

}

void uv_sem_destroy(uv_sem_t* sem) {

  if (!CloseHandle(*sem))

    abort();

}

void uv_sem_post(uv_sem_t* sem) {

  if (!ReleaseSemaphore(*sem, 1, NULL))

    abort();

}

void uv_sem_wait(uv_sem_t* sem) {

  if (WaitForSingleObject(*sem, INFINITE) != WAIT_OBJECT_0)

    abort();

}

int uv_sem_trywait(uv_sem_t* sem) {

  DWORD r = WaitForSingleObject(*sem, 0);

  if (r == WAIT_OBJECT_0)

    return 0;

  if (r == WAIT_TIMEOUT)

    return UV_EAGAIN;

  abort();

  return -1; /* Satisfy the compiler. */

}

int uv_cond_init(uv_cond_t* cond) {

  InitializeConditionVariable(&cond->cond_var);

  return 0;

}

void uv_cond_destroy(uv_cond_t* cond) {

  /* nothing to do */

  (void) &cond;

}

void uv_cond_signal(uv_cond_t* cond) {

  WakeConditionVariable(&cond->cond_var);

}

void uv_cond_broadcast(uv_cond_t* cond) {

  WakeAllConditionVariable(&cond->cond_var);

}

void uv_cond_wait(uv_cond_t* cond, uv_mutex_t* mutex) {

  if (!SleepConditionVariableCS(&cond->cond_var, mutex, INFINITE))

    abort();

}

int uv_cond_timedwait(uv_cond_t* cond, uv_mutex_t* mutex, uint64_t timeout) {

  if (SleepConditionVariableCS(&cond->cond_var, mutex, (DWORD)(timeout / 1e6)))

    return 0;

  if (GetLastError() != ERROR_TIMEOUT)

    abort();

  return UV_ETIMEDOUT;

}

int uv_barrier_init(uv_barrier_t* barrier, unsigned int count) {

  int err;

  barrier->n = count;

  barrier->count = 0;

  err = uv_mutex_init(&barrier->mutex);

  if (err)

    return err;

  err = uv_sem_init(&barrier->turnstile1, 0);

  if (err)

    goto error2;

  err = uv_sem_init(&barrier->turnstile2, 1);

  if (err)

    goto error;

  return 0;

error:

  uv_sem_destroy(&barrier->turnstile1);

error2:

  uv_mutex_destroy(&barrier->mutex);

  return err;

}

void uv_barrier_destroy(uv_barrier_t* barrier) {

  uv_sem_destroy(&barrier->turnstile2);

  uv_sem_destroy(&barrier->turnstile1);

  uv_mutex_destroy(&barrier->mutex);

}

int uv_barrier_wait(uv_barrier_t* barrier) {

  int serial_thread;

  uv_mutex_lock(&barrier->mutex);

  if (++barrier->count == barrier->n) {

    uv_sem_wait(&barrier->turnstile2);

    uv_sem_post(&barrier->turnstile1);

  }

  uv_mutex_unlock(&barrier->mutex);

  uv_sem_wait(&barrier->turnstile1);

  uv_sem_post(&barrier->turnstile1);

  uv_mutex_lock(&barrier->mutex);

  serial_thread = (--barrier->count == 0);

  if (serial_thread) {

    uv_sem_wait(&barrier->turnstile1);

    uv_sem_post(&barrier->turnstile2);

  }

  uv_mutex_unlock(&barrier->mutex);

  uv_sem_wait(&barrier->turnstile2);

  uv_sem_post(&barrier->turnstile2);

  return serial_thread;

}

int uv_key_create(uv_key_t* key) {

  key->tls_index = TlsAlloc();

  if (key->tls_index == TLS_OUT_OF_INDEXES)

    return UV_ENOMEM;

  return 0;

}

void uv_key_delete(uv_key_t* key) {

  if (TlsFree(key->tls_index) == FALSE)

    abort();

  key->tls_index = TLS_OUT_OF_INDEXES;

}

void* uv_key_get(uv_key_t* key) {

  void* value;

  value = TlsGetValue(key->tls_index);

  if (value == NULL)

    if (GetLastError() != ERROR_SUCCESS)

      abort();

  return value;

}

void uv_key_set(uv_key_t* key, void* value) {

  if (TlsSetValue(key->tls_index, value) == FALSE)

    abort();

}