// Filename: threadWin32Impl.cxx
// Created by:  drose (07Feb06)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001 - 2004, Disney Enterprises, Inc.  All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license.  You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://etc.cmu.edu/panda3d/docs/license/ .
//
// To contact the maintainers of this program write to
// panda3d-general@lists.sourceforge.net .
//
////////////////////////////////////////////////////////////////////

#include "threadWin32Impl.h"
#include "selectThreadImpl.h"

#ifdef THREAD_WIN32_IMPL

#include "thread.h"
#include "pointerTo.h"
#include "config_pipeline.h"

DWORD ThreadWin32Impl::_pt_ptr_index = 0;
bool ThreadWin32Impl::_got_pt_ptr_index = false;

////////////////////////////////////////////////////////////////////
//     Function: ThreadWin32Impl::Destructor
//       Access: Public
//  Description: 
////////////////////////////////////////////////////////////////////
ThreadWin32Impl::
~ThreadWin32Impl() {
  if (thread_cat.is_debug()) {
    thread_cat.debug() << "Deleting thread " << _parent_obj->get_name() << "\n";
  }

  CloseHandle(_thread);
}

////////////////////////////////////////////////////////////////////
//     Function: ThreadWin32Impl::start
//       Access: Public
//  Description: 
////////////////////////////////////////////////////////////////////
bool ThreadWin32Impl::
start(ThreadPriority priority, bool global, bool joinable) {
  _mutex.lock();
  if (thread_cat.is_debug()) {
    thread_cat.debug() << "Starting " << *_parent_obj << "\n";
  }

  nassertd(_status == S_new && _thread == 0) {
    _mutex.release();
    return false;
  }

  _joinable = joinable;
  _status = S_start_called;

  if (!_got_pt_ptr_index) {
    init_pt_ptr_index();
  }

  // Increment the parent object's reference count first.  The thread
  // will eventually decrement it when it terminates.
  _parent_obj->ref();
  _thread = 
    CreateThread(NULL, 0, &root_func, (void *)this, 0, &_thread_id);

  if (_thread_id == 0) {
    // Oops, we couldn't start the thread.  Be sure to decrement the
    // reference count we incremented above, and return false to
    // indicate failure.
    unref_delete(_parent_obj);
    _mutex.release();
    return false;
  }

  // Thread was successfully started.  Set the priority as specified.
  switch (priority) {
  case TP_low:
    SetThreadPriority(_thread, THREAD_PRIORITY_BELOW_NORMAL);
    break;

  case TP_high:
    SetThreadPriority(_thread, THREAD_PRIORITY_ABOVE_NORMAL);
    break;

  case TP_urgent:
    SetThreadPriority(_thread, THREAD_PRIORITY_HIGHEST);
    break;

  case TP_normal:
  default:
    SetThreadPriority(_thread, THREAD_PRIORITY_NORMAL);
    break;
  }

  _mutex.release();
  return true;
}

////////////////////////////////////////////////////////////////////
//     Function: ThreadWin32Impl::interrupt
//       Access: Public
//  Description: Sends an interrupt message to the thread.  This will
//               interrupt any blocking-type system calls the thread
//               may be waiting on, such as I/O, so that the thread
//               may continue some other processing.  The specific
//               behavior is implementation dependent.
////////////////////////////////////////////////////////////////////
void ThreadWin32Impl::
interrupt() {
}

////////////////////////////////////////////////////////////////////
//     Function: ThreadWin32Impl::join
//       Access: Public
//  Description: Blocks the calling process until the thread
//               terminates.  If the thread has already terminated,
//               this returns immediately.
////////////////////////////////////////////////////////////////////
void ThreadWin32Impl::
join() {
  _mutex.lock();
  nassertd(_joinable && _status != S_new) {
    _mutex.release();
    return;
  }

  while (_status != S_finished) {
    _cv.wait();
  }
  _mutex.release();
}

////////////////////////////////////////////////////////////////////
//     Function: ThreadWin32Impl::root_func
//       Access: Private, Static
//  Description: The entry point of each thread.
////////////////////////////////////////////////////////////////////
DWORD ThreadWin32Impl::
root_func(LPVOID data) {
  ThreadWin32Impl *self = (ThreadWin32Impl *)data;
  BOOL result = TlsSetValue(_pt_ptr_index, self->_parent_obj);
  nassertr(result, 1);

  {
    self->_mutex.lock();
    nassertd(self->_status == S_start_called) {
      self->_mutex.release();
      return 1;
    }
    self->_status = S_running;
    self->_cv.signal();
    self->_mutex.release();
  }

  self->_parent_obj->thread_main();

  if (thread_cat.is_debug()) {
    thread_cat.debug()
      << "Terminating thread " << self->_parent_obj->get_name() 
      << ", count = " << self->_parent_obj->get_ref_count() << "\n";
  }

  {
    self->_mutex.lock();
    nassertd(self->_status == S_running) {
      self->_mutex.release();
      return 1;
    }
    self->_status = S_finished;
    self->_cv.signal();
    self->_mutex.release();
  }

  // Now drop the parent object reference that we grabbed in start().
  // This might delete the parent object, and in turn, delete the
  // ThreadWin32Impl object.
  unref_delete(self->_parent_obj);

  return 0;
}

////////////////////////////////////////////////////////////////////
//     Function: ThreadWin32Impl::init_pt_ptr_index
//       Access: Private, Static
//  Description: Allocate a new index to store the Thread parent
//               pointer as a piece of per-thread private data.
////////////////////////////////////////////////////////////////////
void ThreadWin32Impl::
init_pt_ptr_index() {
  nassertv(!_got_pt_ptr_index);

  _pt_ptr_index = TlsAlloc();
  if (_pt_ptr_index == TLS_OUT_OF_INDEXES) {
    thread_cat.error()
      << "Unable to associate Thread pointers with threads.\n";
    return;
  }

  _got_pt_ptr_index = true;

  // Assume that we must be in the main thread, since this method must
  // be called before the first thread is spawned.
  Thread *main_thread_obj = Thread::get_main_thread();
  BOOL result = TlsSetValue(_pt_ptr_index, main_thread_obj);
  nassertv(result);
}

#endif  // THREAD_WIN32_IMPL
