/*
 * Copyright (C) 2007, 2009 Apple Inc. All rights reserved.
 * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
 * Copyright (C) 2011 Research In Motion Limited. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  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.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, 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 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "wtf/Threading.h"

#if OS(POSIX)

#include "wtf/CurrentTime.h"
#include "wtf/DateMath.h"
#include "wtf/HashMap.h"
#include "wtf/StdLibExtras.h"
#include "wtf/ThreadSpecific.h"
#include "wtf/ThreadingPrimitives.h"
#include "wtf/WTFThreadData.h"
#include "wtf/dtoa/double-conversion.h"
#include <errno.h>
#include <limits.h>
#include <sched.h>
#include <sys/time.h>

#if OS(MACOSX)
#include <objc/objc-auto.h>
#endif

#if OS(LINUX)
#include <sys/syscall.h>
#endif

#if OS(LINUX) || OS(ANDROID)
#include <unistd.h>
#endif

namespace WTF {

namespace internal {

ThreadIdentifier currentThreadSyscall() {
#if OS(MACOSX)
  return pthread_mach_thread_np(pthread_self());
#elif OS(LINUX)
  return syscall(__NR_gettid);
#elif OS(ANDROID)
  return gettid();
#else
  return reinterpret_cast<uintptr_t>(pthread_self());
#endif
}

}  // namespace internal

void initializeThreading() {
  // This should only be called once.
  WTFThreadData::initialize();

  initializeDates();
  // Force initialization of static DoubleToStringConverter converter variable
  // inside EcmaScriptConverter function while we are in single thread mode.
  double_conversion::DoubleToStringConverter::EcmaScriptConverter();
}

namespace {
ThreadSpecificKey s_currentThreadKey;
bool s_currentThreadKeyInitialized = false;
}  // namespace

void initializeCurrentThread() {
  DCHECK(!s_currentThreadKeyInitialized);
  threadSpecificKeyCreate(&s_currentThreadKey, [](void*) {});
  s_currentThreadKeyInitialized = true;
}

ThreadIdentifier currentThread() {
  // This doesn't use WTF::ThreadSpecific (e.g. WTFThreadData) because
  // ThreadSpecific now depends on currentThread. It is necessary to avoid this
  // or a similar loop:
  //
  // currentThread
  // -> wtfThreadData
  // -> ThreadSpecific::operator*
  // -> isMainThread
  // -> currentThread
  static_assert(sizeof(ThreadIdentifier) <= sizeof(void*),
                "ThreadIdentifier must fit in a void*.");
  DCHECK(s_currentThreadKeyInitialized);
  void* value = threadSpecificGet(s_currentThreadKey);
  if (UNLIKELY(!value)) {
    value = reinterpret_cast<void*>(
        static_cast<intptr_t>(internal::currentThreadSyscall()));
    DCHECK(value);
    threadSpecificSet(s_currentThreadKey, value);
  }
  return reinterpret_cast<intptr_t>(threadSpecificGet(s_currentThreadKey));
}

MutexBase::MutexBase(bool recursive) {
  pthread_mutexattr_t attr;
  pthread_mutexattr_init(&attr);
  pthread_mutexattr_settype(
      &attr, recursive ? PTHREAD_MUTEX_RECURSIVE : PTHREAD_MUTEX_NORMAL);

  int result = pthread_mutex_init(&m_mutex.m_internalMutex, &attr);
  DCHECK_EQ(result, 0);
#if DCHECK_IS_ON()
  m_mutex.m_recursionCount = 0;
#endif

  pthread_mutexattr_destroy(&attr);
}

MutexBase::~MutexBase() {
  int result = pthread_mutex_destroy(&m_mutex.m_internalMutex);
  DCHECK_EQ(result, 0);
}

void MutexBase::lock() {
  int result = pthread_mutex_lock(&m_mutex.m_internalMutex);
  DCHECK_EQ(result, 0);
#if DCHECK_IS_ON()
  ++m_mutex.m_recursionCount;
#endif
}

void MutexBase::unlock() {
#if DCHECK_IS_ON()
  DCHECK(m_mutex.m_recursionCount);
  --m_mutex.m_recursionCount;
#endif
  int result = pthread_mutex_unlock(&m_mutex.m_internalMutex);
  DCHECK_EQ(result, 0);
}

// There is a separate tryLock implementation for the Mutex and the
// RecursiveMutex since on Windows we need to manually check if tryLock should
// succeed or not for the non-recursive mutex. On Linux the two implementations
// are equal except we can assert the recursion count is always zero for the
// non-recursive mutex.
bool Mutex::tryLock() {
  int result = pthread_mutex_trylock(&m_mutex.m_internalMutex);
  if (result == 0) {
#if DCHECK_IS_ON()
    // The Mutex class is not recursive, so the recursionCount should be
    // zero after getting the lock.
    DCHECK(!m_mutex.m_recursionCount);
    ++m_mutex.m_recursionCount;
#endif
    return true;
  }
  if (result == EBUSY)
    return false;

  NOTREACHED();
  return false;
}

bool RecursiveMutex::tryLock() {
  int result = pthread_mutex_trylock(&m_mutex.m_internalMutex);
  if (result == 0) {
#if DCHECK_IS_ON()
    ++m_mutex.m_recursionCount;
#endif
    return true;
  }
  if (result == EBUSY)
    return false;

  NOTREACHED();
  return false;
}

ThreadCondition::ThreadCondition() {
  pthread_cond_init(&m_condition, nullptr);
}

ThreadCondition::~ThreadCondition() {
  pthread_cond_destroy(&m_condition);
}

void ThreadCondition::wait(MutexBase& mutex) {
  PlatformMutex& platformMutex = mutex.impl();
  int result = pthread_cond_wait(&m_condition, &platformMutex.m_internalMutex);
  DCHECK_EQ(result, 0);
#if DCHECK_IS_ON()
  ++platformMutex.m_recursionCount;
#endif
}

bool ThreadCondition::timedWait(MutexBase& mutex, double absoluteTime) {
  if (absoluteTime < currentTime())
    return false;

  if (absoluteTime > INT_MAX) {
    wait(mutex);
    return true;
  }

  int timeSeconds = static_cast<int>(absoluteTime);
  int timeNanoseconds = static_cast<int>((absoluteTime - timeSeconds) * 1E9);

  timespec targetTime;
  targetTime.tv_sec = timeSeconds;
  targetTime.tv_nsec = timeNanoseconds;

  PlatformMutex& platformMutex = mutex.impl();
  int result = pthread_cond_timedwait(
      &m_condition, &platformMutex.m_internalMutex, &targetTime);
#if DCHECK_IS_ON()
  ++platformMutex.m_recursionCount;
#endif
  return result == 0;
}

void ThreadCondition::signal() {
  int result = pthread_cond_signal(&m_condition);
  DCHECK_EQ(result, 0);
}

void ThreadCondition::broadcast() {
  int result = pthread_cond_broadcast(&m_condition);
  DCHECK_EQ(result, 0);
}

#if DCHECK_IS_ON()
static bool s_threadCreated = false;

bool isBeforeThreadCreated() {
  return !s_threadCreated;
}

void willCreateThread() {
  s_threadCreated = true;
}
#endif

}  // namespace WTF

#endif  // OS(POSIX)