// Copyright (c) 2011 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/memory/lock_impl.h"

#if defined(OS_WIN)

namespace base {
namespace internal {

LockImpl::LockImpl() {
  // The second parameter is the spin count, for short-held locks it avoid the
  // contending thread from going to sleep which helps performance greatly.
  ::InitializeCriticalSectionAndSpinCount(&native_handle_, 2000);
}

LockImpl::~LockImpl() { ::DeleteCriticalSection(&native_handle_); }

bool LockImpl::Try() {
  if (::TryEnterCriticalSection(&native_handle_) != FALSE) {
    return true;
  }
  return false;
}

void LockImpl::Lock() { ::EnterCriticalSection(&native_handle_); }

void LockImpl::Unlock() { ::LeaveCriticalSection(&native_handle_); }

}  // namespace internal
}  // namespace base

#elif defined(OS_POSIX)

#include <errno.h>
#include <string.h>

#include "base/debug/logging.h"

namespace base {
namespace internal {

LockImpl::LockImpl() {
#if DCHECK_IS_ON()
  // In debug, setup attributes for lock error checking.
  pthread_mutexattr_t mta;
  int rv = pthread_mutexattr_init(&mta);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
  rv = pthread_mutexattr_settype(&mta, PTHREAD_MUTEX_ERRORCHECK);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
  rv = pthread_mutex_init(&native_handle_, &mta);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
  rv = pthread_mutexattr_destroy(&mta);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
#else
  // In release, go with the default lock attributes.
  pthread_mutex_init(&native_handle_, NULL);
#endif
}

LockImpl::~LockImpl() {
  int rv = pthread_mutex_destroy(&native_handle_);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
}

bool LockImpl::Try() {
  int rv = pthread_mutex_trylock(&native_handle_);
  DCHECK(rv == 0 || rv == EBUSY) << ". " << strerror(rv);
  return rv == 0;
}

void LockImpl::Lock() {
  int rv = pthread_mutex_lock(&native_handle_);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
}

void LockImpl::Unlock() {
  int rv = pthread_mutex_unlock(&native_handle_);
  DCHECK_EQ(rv, 0) << ". " << strerror(rv);
}

}  // namespace internal
}  // namespace base

#endif  // defined(OS_POSIX)
