/************************************************************************************

Filename    :   Logging_Tools.cpp
Content     :   Tools for Logging
Created     :   Oct 26, 2015
Authors     :   Chris Taylor

Copyright   :   Copyright (c) Facebook Technologies, LLC and its affiliates. All rights reserved.

Licensed under the Oculus Master SDK License Version 1.0 (the "License");
you may not use the Oculus VR Rift SDK except in compliance with the License,
which is provided at the time of installation or download, or which
otherwise accompanies this software in either electronic or hard copy form.

You may obtain a copy of the License at

https://developer.oculus.com/licenses/oculusmastersdk-1.0

Unless required by applicable law or agreed to in writing, the Oculus VR SDK
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

************************************************************************************/

#ifdef _MSC_VER
#pragma warning(disable : 4530) // C++ exception handler used, but unwind semantics are not enabled
#endif

#include "Logging/Logging_Tools.h"

#include <assert.h>
#include <time.h>

#if defined(__APPLE__)
#include <libproc.h>
#include <sys/sysctl.h>
#include <unistd.h>
#include <locale>
#endif

namespace ovrlog {

#if defined(_WIN32)
//-----------------------------------------------------------------------------
// Terminator

Terminator::Terminator() : Terminated(false), TerminateEvent() {}

Terminator::~Terminator() {}

bool Terminator::Initialize() {
  Terminated = false;

  if (TerminateEvent.IsValid()) {
    ::ResetEvent(TerminateEvent.Get());
    return true;
  }

  TerminateEvent = ::CreateEventW(nullptr, TRUE, FALSE, nullptr);

  return TerminateEvent.IsValid();
}

void Terminator::Terminate() {
  Terminated = true;

  if (TerminateEvent.IsValid()) {
    ::SetEvent(TerminateEvent.Get());
  }
}

// Returns true if the event signaled and false on termination.
bool Terminator::WaitOn(OvrLogHandle hEvent, uint32_t timeoutMsec) {
  if (Terminated || !TerminateEvent.IsValid())
    return false;

  HANDLE events[2] = {hEvent, TerminateEvent.Get()};

  DWORD result = ::WaitForMultipleObjects(2, events, FALSE, timeoutMsec);

  if (Terminated)
    return false;

  if (result == WAIT_TIMEOUT)
    return false;
  if (result == WAIT_OBJECT_0)
    return true;

  return false;
}

// Returns true if the sleep interval exceeded or false on termination.
bool Terminator::WaitSleep(int milliseconds) {
  if (Terminated || !TerminateEvent.IsValid())
    return false;

  ::WaitForSingleObject(TerminateEvent.Get(), milliseconds); // Ignore return value

  return !Terminated;
}
#endif // defined(_WIN32)

//-----------------------------------------------------------------------------
// Lock

Lock::Lock()
    :
#if defined(_WIN32)
      cs {
}
#else
      m()
#endif
{
#if defined(_WIN32)
  static const DWORD kSpinCount = 1000;
  ::InitializeCriticalSectionAndSpinCount(&cs, kSpinCount);
#endif
}

Lock::~Lock() {
#if defined(_WIN32)
  ::DeleteCriticalSection(&cs);
#endif
}

bool Lock::TryEnter() {
#if defined(_WIN32)
  return ::TryEnterCriticalSection(&cs) != FALSE;
#else
  return m.try_lock();
#endif
}

void Lock::Enter() {
#if defined(_WIN32)
  ::EnterCriticalSection(&cs);
#else
  m.lock();
#endif
}

void Lock::Leave() {
#if defined(_WIN32)
  ::LeaveCriticalSection(&cs);
#else
  m.unlock();
#endif
}

//-----------------------------------------------------------------------------
// Locker

Locker::Locker(Lock* lock) : TheLock(lock) {
  if (TheLock)
    TheLock->Enter();
}

Locker::Locker(Lock& lock) : TheLock(&lock) {
  if (TheLock)
    TheLock->Enter();
}

Locker::~Locker() {
  Clear();
}

bool Locker::TrySet(Lock* lock) {
  Clear();

  if (!lock || !lock->TryEnter())
    return false;

  TheLock = lock;
  return true;
}

bool Locker::TrySet(Lock& lock) {
  return TrySet(&lock);
}

void Locker::Set(Lock* lock) {
  Clear();

  if (lock) {
    lock->Enter();
    TheLock = lock;
  }
}

void Locker::Set(Lock& lock) {
  return Set(&lock);
}

void Locker::Clear() {
  if (TheLock) {
    TheLock->Leave();
    TheLock = nullptr;
  }
}

#if defined(_WIN32)
//-----------------------------------------------------------------------------
// AutoHandle

AutoHandle::AutoHandle(OvrLogHandle handle) : TheHandle(handle) {}

AutoHandle::~AutoHandle() {
  Clear();
}

void AutoHandle::operator=(OvrLogHandle handle) {
  Clear();
  TheHandle = handle;
}

void AutoHandle::Clear() {
  if (TheHandle) {
    ::CloseHandle(TheHandle);
    TheHandle = nullptr;
  }
}
#endif // defined(_WIN32)

//-----------------------------------------------------------------------------
// Tools

bool IsDebuggerAttached() {
#if defined(_WIN32)
  return ::IsDebuggerPresent() != FALSE;
#elif defined(__APPLE__)
  int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, getpid()};
  struct kinfo_proc info;
  size_t size = sizeof(info);

  info.kp_proc.p_flag = 0;
  sysctl(mib, sizeof(mib) / sizeof(*mib), &info, &size, nullptr, 0);

  return ((info.kp_proc.p_flag & P_TRACED) != 0);

#elif defined(PT_TRACE_ME) && !defined(__android__)
  return (ptrace(PT_TRACE_ME, 0, 1, 0) < 0);
#else
  // We have some platform-specific code elsewhere.
  return false;
#endif
}

} // namespace ovrlog

#ifdef OVR_STRINGIZE
#error "This code must remain independent of LibOVR"
#endif