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[wxWidgets.git] / src / mac / carbon / thread.cpp
index 82fff92ba38b9fca81d02e7d8461e031c73aa6b8..a37865ee7a5768bb344ed0d63dc07c9fa887c498 100644 (file)
 /////////////////////////////////////////////////////////////////////////////
 // Name:        thread.cpp
-// Purpose:     wxThread Implementation. For Unix ports, see e.g. src/gtk
-// Author:      Original from Wolfram Gloger/Guilhem Lavaux
-// Modified by:
+// Purpose:     wxThread Implementation
+// Author:      Original from Wolfram Gloger/Guilhem Lavaux/Vadim Zeitlin
+// Modified by: Stefan Csomor
 // Created:     04/22/98
 // RCS-ID:      $Id$
-// Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998)
+// Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
+//                  Vadim Zeitlin (1999) , Stefan Csomor (2000)
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 #ifdef __GNUG__
-#pragma implementation "thread.h"
+    #pragma implementation "thread.h"
 #endif
 
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// For compilers that support precompilation, includes "wx.h".
+#include "wx/wxprec.h"
+
+#if defined(__BORLANDC__)
+    #pragma hdrstop
+#endif
+
+#ifndef WX_PRECOMP
+    #include "wx/wx.h"
+#endif
+
+#if wxUSE_THREADS
+
 #include "wx/module.h"
 #include "wx/thread.h"
-#include "wx/utils.h"
 
-enum thread_state {
-  STATE_IDLE = 0,
-  STATE_RUNNING,
-  STATE_CANCELED,
-  STATE_EXITED
+// ----------------------------------------------------------------------------
+// constants
+// ----------------------------------------------------------------------------
+
+// the possible states of the thread ("=>" shows all possible transitions from
+// this state)
+enum wxThreadState
+{
+    STATE_NEW,          // didn't start execution yet (=> RUNNING)
+    STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
+    STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
+    STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
+    STATE_EXITED        // thread is terminating
 };
 
-/////////////////////////////////////////////////////////////////////////////
-// Static variables
-/////////////////////////////////////////////////////////////////////////////
+// ----------------------------------------------------------------------------
+// this module globals
+// ----------------------------------------------------------------------------
 
-wxMutex *wxMainMutex; // controls access to all GUI functions
+static ThreadID gs_idMainThread = kNoThreadID ;
+static bool gs_waitingForThread = FALSE ;
 
-/////////////////////////////////////////////////////////////////////////////
-// Windows implementation
-/////////////////////////////////////////////////////////////////////////////
+// ============================================================================
+// MacOS implementation of thread classes
+// ============================================================================
 
-class wxMutexInternal {
+class wxMacStCritical
+{
+public :
+       wxMacStCritical() 
+       {
+               ThreadBeginCritical() ;
+       }
+       ~wxMacStCritical()
+       {
+               ThreadEndCritical() ;
+       }
+} ;
+
+// ----------------------------------------------------------------------------
+// wxMutex implementation
+// ----------------------------------------------------------------------------
+
+class wxMutexInternal
+{
 public:
-  // TODO: internal mutex handle
+    wxMutexInternal()
+    {
+       m_owner = kNoThreadID ;
+    }
+
+    ~wxMutexInternal() 
+    {
+    }
+
+public:
+    ThreadID m_owner ;
+    wxArrayLong m_waiters ;
 };
 
 wxMutex::wxMutex()
 {
-    p_internal = new wxMutexInternal;
-    // TODO: create internal mutext handle
+    m_internal = new wxMutexInternal;
+
     m_locked = 0;
 }
 
 wxMutex::~wxMutex()
 {
-    if (m_locked > 0)
-        wxDebugMsg("wxMutex warning: freeing a locked mutex (%d locks)\n", m_locked);
-    // TODO: free internal mutext handle
+    if ( m_locked > 0 )
+    {
+        wxLogDebug(_T("Warning: freeing a locked mutex (%d locks)."), m_locked);
+    }
+
+    delete m_internal;
 }
 
 wxMutexError wxMutex::Lock()
 {
-    // TODO
+       wxMacStCritical critical ;
+       
+       OSErr err ;
+       ThreadID current = kNoThreadID;
+       err = ::MacGetCurrentThread(&current);
+       // if we are not the owner, add this thread to the list of waiting threads, stop this thread
+       // and invoke the scheduler to continue executing the owner's thread
+       while ( m_internal->m_owner != kNoThreadID && m_internal->m_owner != current) 
+       {
+               m_internal->m_waiters.Add(current);
+               err = ::SetThreadStateEndCritical(kCurrentThreadID, kStoppedThreadState, m_internal->m_owner);
+               err = ::ThreadBeginCritical();
+       }
+       m_internal->m_owner = current;
     m_locked++;
+
     return wxMUTEX_NO_ERROR;
 }
 
 wxMutexError wxMutex::TryLock()
 {
-    // TODO
+       wxMacStCritical critical ;
+       
+       OSErr err ;
+       ThreadID current = kNoThreadID;
+       ::MacGetCurrentThread(&current);
+       // if we are not the owner, give an error back
+       if ( m_internal->m_owner != kNoThreadID && m_internal->m_owner != current ) 
+        return wxMUTEX_BUSY;
+               
+       m_internal->m_owner = current;
     m_locked++;
-    return wxMUTEX_NO_ERROR;
+
+   return wxMUTEX_NO_ERROR;
 }
 
 wxMutexError wxMutex::Unlock()
 {
+       OSErr err;
+       err = ::ThreadBeginCritical();
+       
     if (m_locked > 0)
         m_locked--;
 
-    // TODO
+       // this mutex is not owned by anybody anmore
+       m_internal->m_owner = kNoThreadID;
+
+       // now pass on to the first waiting thread
+       ThreadID firstWaiting = kNoThreadID;
+       bool found = false;
+       while (!m_internal->m_waiters.IsEmpty() && !found) 
+       {
+               firstWaiting = m_internal->m_waiters[0];
+               err = ::SetThreadState(firstWaiting, kReadyThreadState, kNoThreadID);
+               // in case this was not successful (dead thread), we just loop on and reset the id
+               found = (err != threadNotFoundErr);     
+               if ( !found )
+                       firstWaiting = kNoThreadID ;
+               m_internal->m_waiters.RemoveAt(0) ;
+       }
+       // now we have a valid firstWaiting thread, which has been scheduled to run next, just end the
+       // critical section and invoke the scheduler
+       err = ::SetThreadStateEndCritical(kCurrentThreadID, kReadyThreadState, firstWaiting);
+
     return wxMUTEX_NO_ERROR;
 }
 
-class wxConditionInternal {
+// ----------------------------------------------------------------------------
+// wxCondition implementation
+// ----------------------------------------------------------------------------
+
+class wxConditionInternal
+{
 public:
-  // TODO: internal handle
-  int waiters;
+    wxConditionInternal()
+    {
+       m_excessSignals = 0 ;
+    }
+    ~wxConditionInternal()
+    {
+    }
+
+    bool Wait(unsigned long msectimeout)
+    {
+               wxMacStCritical critical ;
+       if ( m_excessSignals > 0 )
+       {
+               --m_excessSignals ;
+               return TRUE ;
+       }
+       else if ( msectimeout == 0 )
+       {
+               return FALSE ;
+       }
+       else
+       {
+               }
+               /*
+        waiters++;
+
+        // FIXME this should be MsgWaitForMultipleObjects() as well probably
+        DWORD rc = ::WaitForSingleObject(event, timeout);
+
+        waiters--;
+
+        return rc != WAIT_TIMEOUT;
+        */
+        return TRUE ;
+    }
+       void Signal()
+       {
+               wxMacStCritical critical ;
+       }
+
+    wxArrayLong m_waiters ;
+    wxInt32            m_excessSignals ;
 };
 
 wxCondition::wxCondition()
 {
-    p_internal = new wxConditionInternal;
-    // TODO: create internal handle
-    p_internal->waiters = 0;
+    m_internal = new wxConditionInternal;
 }
 
 wxCondition::~wxCondition()
 {
-    // TODO: destroy internal handle
+    delete m_internal;
 }
 
-void wxCondition::Wait(wxMutex& mutex)
+void wxCondition::Wait()
 {
-    mutex.Unlock();
-    p_internal->waiters++;
-    // TODO wait here
-    p_internal->waiters--;
-    mutex.Lock();
+    (void)m_internal->Wait(0xFFFFFFFFL );
 }
 
-bool wxCondition::Wait(wxMutex& mutex, unsigned long sec,
+bool wxCondition::Wait(unsigned long sec,
                        unsigned long nsec)
 {
-    mutex.Unlock();
-    p_internal->waiters++;
-
-    // TODO wait here
-    p_internal->waiters--;
-    mutex.Lock();
-
-    return FALSE;
+    return m_internal->Wait(sec*1000 + nsec/1000000);
 }
 
 void wxCondition::Signal()
 {
-    // TODO
+    // set the event to signaled: if a thread is already waiting on it, it will
+    // be woken up, otherwise the event will remain in the signaled state until
+    // someone waits on it. In any case, the system will return it to a non
+    // signalled state afterwards. If multiple threads are waiting, only one
+    // will be woken up.
+       m_internal->Signal() ;
 }
 
 void wxCondition::Broadcast()
 {
-    // TODO
+    // this works because all these threads are already waiting and so each
+    // SetEvent() inside Signal() is really a PulseEvent() because the event
+    // state is immediately returned to non-signaled
+    for ( int i = 0; i < m_internal->m_waiters.Count(); i++ )
+    {
+        Signal();
+    }
 }
 
-class wxThreadInternal {
+// ----------------------------------------------------------------------------
+// wxCriticalSection implementation
+// ----------------------------------------------------------------------------
+
+// it's implemented as a mutex on mac os, so it is defined in the headers
+
+// ----------------------------------------------------------------------------
+// wxThread implementation
+// ----------------------------------------------------------------------------
+
+// wxThreadInternal class
+// ----------------------
+
+class wxThreadInternal
+{
 public:
-    // TODO
+    wxThreadInternal()
+    {
+        m_tid = kNoThreadID ;
+        m_state = STATE_NEW;
+        m_priority = WXTHREAD_DEFAULT_PRIORITY;
+    }
+
+    ~wxThreadInternal()
+    {
+    }
+
+    void Free()
+    {
+    }
+
+    // create a new (suspended) thread (for the given thread object)
+    bool Create(wxThread *thread);
+
+    // suspend/resume/terminate
+    bool Suspend();
+    bool Resume();
+    void Cancel() { m_state = STATE_CANCELED; }
+
+    // thread state
+    void SetState(wxThreadState state) { m_state = state; }
+    wxThreadState GetState() const { return m_state; }
+
+    // thread priority
+    void SetPriority(unsigned int priority);
+    unsigned int GetPriority() const { return m_priority; }
+    
+    void SetResult( void *res ) { m_result = res ; }
+    void *GetResult() { return m_result ; }
+
+    // thread handle and id
+    ThreadID  GetId() const { return m_tid; }
+
+    // thread function
+       static pascal void*     MacThreadStart(wxThread* arg);
+
+private:
+    wxThreadState      m_state;      // state, see wxThreadState enum
+    unsigned int       m_priority;   // thread priority in "wx" units
+    ThreadID        m_tid;        // thread id
+    void *                     m_result ;
+    static ThreadEntryUPP s_threadEntry ;
+public :
 };
 
+static wxArrayPtrVoid s_threads ;
+
+ThreadEntryUPP wxThreadInternal::s_threadEntry = NULL ;
+pascal void* wxThreadInternal::MacThreadStart(wxThread *thread)
+{
+    // first of all, check whether we hadn't been cancelled already
+    if ( thread->m_internal->GetState() == STATE_EXITED )
+    {
+        return (void*)-1;
+    }
+
+    void* rc = thread->Entry();
+
+    // enter m_critsect before changing the thread state
+    thread->m_critsect.Enter();
+    bool wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
+    thread->m_internal->SetState(STATE_EXITED);
+    thread->m_critsect.Leave();
+
+    thread->OnExit();
+
+    // if the thread was cancelled (from Delete()), then it the handle is still
+    // needed there
+    if ( thread->IsDetached() && !wasCancelled )
+    {
+        // auto delete
+        delete thread;
+    }
+    //else: the joinable threads handle will be closed when Wait() is done
+
+    return rc;
+}
+void wxThreadInternal::SetPriority(unsigned int priority)
+{
+       // Priorities don't exist on Mac
+}
+
+bool wxThreadInternal::Create(wxThread *thread)
+{
+       if ( s_threadEntry == NULL )
+       {
+               s_threadEntry = NewThreadEntryUPP( (ThreadEntryProcPtr) MacThreadStart ) ;
+       }
+       OSErr err = NewThread(kCooperativeThread,
+               s_threadEntry,
+               (void*) thread ,
+               0 ,
+               kNewSuspend ,
+               &m_result ,
+               &m_tid ) ;
+
+    if ( err != noErr )
+    {
+        wxLogSysError(_("Can't create thread"));
+        return FALSE;
+    }
+
+    if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
+    {
+        SetPriority(m_priority);
+    }
+
+    return TRUE;
+}
+
+bool wxThreadInternal::Suspend()
+{
+       OSErr err ;
+       
+       ::ThreadBeginCritical();
+
+       if ( m_state != STATE_RUNNING )
+    {
+       ::ThreadEndCritical() ;
+        wxLogSysError(_("Can not suspend thread %x"), m_tid);
+        return FALSE;
+    }
+
+    m_state = STATE_PAUSED;
+
+       err = ::SetThreadStateEndCritical(m_tid, kStoppedThreadState, kNoThreadID);
+
+    return TRUE;
+}
+
+bool wxThreadInternal::Resume()
+{
+       ThreadID current ;
+       OSErr err ;
+       err = MacGetCurrentThread( &current ) ;
+
+       wxASSERT( err == noErr ) ;
+       wxASSERT( current != m_tid ) ;
+               
+       ::ThreadBeginCritical();
+       if ( m_state != STATE_PAUSED && m_state != STATE_NEW )
+       {
+       ::ThreadEndCritical() ;
+        wxLogSysError(_("Can not resume thread %x"), m_tid);
+        return FALSE;
+               
+       }
+       err = ::SetThreadStateEndCritical(m_tid, kReadyThreadState, kNoThreadID);
+       wxASSERT( err == noErr ) ;
+       
+    m_state = STATE_RUNNING;
+       ::ThreadEndCritical() ;
+       ::YieldToAnyThread() ;
+    return TRUE;
+}
+
+// static functions
+// ----------------
+wxThread *wxThread::This()
+{
+       wxMacStCritical critical ;
+       
+       ThreadID current ;
+       OSErr err ;
+       
+       err = MacGetCurrentThread( &current ) ;
+       
+       for ( int i = 0 ; i < s_threads.Count() ; ++i )
+       {
+               if ( ( (wxThread*) s_threads[i] )->GetId() == current )
+                       return (wxThread*) s_threads[i] ;
+       }
+
+    wxLogSysError(_("Couldn't get the current thread pointer"));
+    return NULL;
+}
+
+bool wxThread::IsMain()
+{
+       ThreadID current ;
+       OSErr err ;
+       
+       err = MacGetCurrentThread( &current ) ;
+    return current == gs_idMainThread;
+}
+
+#ifdef Yield
+#undef Yield
+#endif
+
+void wxThread::Yield()
+{
+       ::YieldToAnyThread() ;
+}
+
+void wxThread::Sleep(unsigned long milliseconds)
+{
+               clock_t start = clock() ;
+               do 
+               {
+                       YieldToAnyThread() ;
+               } while( clock() - start < milliseconds / CLOCKS_PER_SEC ) ;
+}
+
+int wxThread::GetCPUCount()
+{
+       // we will use whatever MP API will be used for the new MP Macs
+    return 1;
+}
+
+bool wxThread::SetConcurrency(size_t level)
+{
+    wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
+
+    // ok only for the default one
+    if ( level == 0 )
+        return 0;
+
+    // how many CPUs have we got?
+    if ( GetCPUCount() == 1 )
+    {
+        // don't bother with all this complicated stuff - on a single
+        // processor system it doesn't make much sense anyhow
+        return level == 1;
+    }
+    
+    return TRUE ;
+}
+
+// ctor and dtor
+// -------------
+
+wxThread::wxThread(wxThreadKind kind)
+{
+    m_internal = new wxThreadInternal();
+
+    m_isDetached = kind == wxTHREAD_DETACHED;
+    s_threads.Add( (void*) this ) ;
+}
+
+wxThread::~wxThread()
+{
+       s_threads.Remove( (void*) this ) ;
+    delete m_internal;
+}
+
+// create/start thread
+// -------------------
+
 wxThreadError wxThread::Create()
 {
-    // TODO
+    wxCriticalSectionLocker lock(m_critsect);
+
+    if ( !m_internal->Create(this) )
+        return wxTHREAD_NO_RESOURCE;
+
     return wxTHREAD_NO_ERROR;
 }
 
-wxThreadError wxThread::Destroy()
+wxThreadError wxThread::Run()
 {
-    // TODO
-    return wxTHREAD_NO_ERROR;
+    wxCriticalSectionLocker lock(m_critsect);
+
+    if ( m_internal->GetState() != STATE_NEW )
+    {
+        // actually, it may be almost any state at all, not only STATE_RUNNING
+        return wxTHREAD_RUNNING;
+    }
+
+    // the thread has just been created and is still suspended - let it run
+    return Resume();
 }
 
+// suspend/resume thread
+// ---------------------
+
 wxThreadError wxThread::Pause()
 {
-    // TODO
-    return wxTHREAD_NO_ERROR;
+    wxCriticalSectionLocker lock(m_critsect);
+
+    return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 }
 
 wxThreadError wxThread::Resume()
 {
-    // TODO
-    return wxTHREAD_NO_ERROR;
+    wxCriticalSectionLocker lock(m_critsect);
+
+    return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 }
 
-void wxThread::Exit(void *status)
+// stopping thread
+// ---------------
+
+wxThread::ExitCode wxThread::Wait()
 {
-    // TODO
+    // although under MacOS we can wait for any thread, it's an error to
+    // wait for a detached one in wxWin API
+    wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
+                 _T("can't wait for detached thread") );
+
+    ExitCode rc = (ExitCode)-1;
+
+    (void)Delete(&rc);
+
+    m_internal->Free();
+
+    return rc;
 }
 
-void wxThread::SetPriority(int prio)
+wxThreadError wxThread::Delete(ExitCode *pRc)
 {
-    // TODO
+    ExitCode rc = 0;
+
+    // Delete() is always safe to call, so consider all possible states
+
+    // has the thread started to run?
+    bool shouldResume = FALSE;
+
+    {
+        wxCriticalSectionLocker lock(m_critsect);
+
+        if ( m_internal->GetState() == STATE_NEW )
+        {
+            // WinThreadStart() will see it and terminate immediately
+            m_internal->SetState(STATE_EXITED);
+
+            shouldResume = TRUE;
+        }
+    }
+
+    // is the thread paused?
+    if ( shouldResume || IsPaused() )
+        Resume();
+
+    // does is still run?
+    if ( IsRunning() )
+    {
+        if ( IsMain() )
+        {
+            // set flag for wxIsWaitingForThread()
+            gs_waitingForThread = TRUE;
+
+#if wxUSE_GUI
+            wxBeginBusyCursor();
+#endif // wxUSE_GUI
+        }
+
+        // ask the thread to terminate
+        {
+            wxCriticalSectionLocker lock(m_critsect);
+
+            m_internal->Cancel();
+        }
+
+#if wxUSE_GUI
+        // simply wait for the thread to terminate
+               while( TestDestroy() )
+               {
+                       ::YieldToAnyThread() ;
+               }
+#else // !wxUSE_GUI
+        // simply wait for the thread to terminate
+               while( TestDestroy() )
+               {
+                       ::YieldToAnyThread() ;
+               }
+#endif // wxUSE_GUI/!wxUSE_GUI
+
+        if ( IsMain() )
+        {
+            gs_waitingForThread = FALSE;
+
+#if wxUSE_GUI
+            wxEndBusyCursor();
+#endif // wxUSE_GUI
+        }
+    }
+
+ //   if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
+    {
+        wxLogLastError("GetExitCodeThread");
+
+        rc = (ExitCode)-1;
+    }
+
+    if ( IsDetached() )
+    {
+        // if the thread exits normally, this is done in WinThreadStart, but in
+        // this case it would have been too early because
+        // MsgWaitForMultipleObject() would fail if the therad handle was
+        // closed while we were waiting on it, so we must do it here
+        delete this;
+    }
+
+ //   wxASSERT_MSG( (DWORD)rc != STILL_ACTIVE,
+ //                 wxT("thread must be already terminated.") );
+
+    if ( pRc )
+        *pRc = rc;
+
+    return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
 }
 
-int wxThread::GetPriority() const
+wxThreadError wxThread::Kill()
 {
-    // TODO
-    return 0;
+    if ( !IsRunning() )
+        return wxTHREAD_NOT_RUNNING;
+
+//    if ( !::TerminateThread(m_internal->GetHandle(), (DWORD)-1) )
+    {
+        wxLogSysError(_("Couldn't terminate thread"));
+
+        return wxTHREAD_MISC_ERROR;
+    }
+
+    m_internal->Free();
+
+    if ( IsDetached() )
+    {
+        delete this;
+    }
+
+    return wxTHREAD_NO_ERROR;
 }
 
-void wxThread::DeferDestroy(bool on)
+void wxThread::Exit(ExitCode status)
 {
-    // TODO
+    m_internal->Free();
+
+    if ( IsDetached() )
+    {
+        delete this;
+    }
+
+       m_internal->SetResult( status ) ;
+
+/*     
+#if defined(__VISUALC__) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500))
+    _endthreadex((unsigned)status);
+#else // !VC++
+    ::ExitThread((DWORD)status);
+#endif // VC++/!VC++
+*/
+    wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
 }
 
-void wxThread::TestDestroy()
+// priority setting
+// ----------------
+
+// since all these calls are execute cooperatively we don't have to use the critical section
+
+void wxThread::SetPriority(unsigned int prio)
 {
-    // TODO
+    m_internal->SetPriority(prio);
 }
 
-void *wxThread::Join()
+unsigned int wxThread::GetPriority() const
 {
-    // TODO
-    return (void*) NULL;
+    return m_internal->GetPriority();
 }
 
-unsigned long wxThread::GetID() const
+unsigned long wxThread::GetId() const
 {
-    // TODO
-    return 0;
+    return (unsigned long)m_internal->GetId();
 }
 
-/* is this needed somewhere ?
-wxThread *wxThread::GetThreadFromID(unsigned long id)
+bool wxThread::IsRunning() const
 {
-    // TODO
-    return NULL;
+    return m_internal->GetState() == STATE_RUNNING;
 }
-*/
 
 bool wxThread::IsAlive() const
 {
-    // TODO
-    return FALSE;
+    return (m_internal->GetState() == STATE_RUNNING) ||
+           (m_internal->GetState() == STATE_PAUSED);
 }
 
-bool wxThread::IsRunning() const
+bool wxThread::IsPaused() const
 {
-    // TODO
-    return FALSE;
+    return m_internal->GetState() == STATE_PAUSED;
 }
 
-bool wxThread::IsMain()
+bool wxThread::TestDestroy()
+{
+    return m_internal->GetState() == STATE_CANCELED;
+}
+
+// ----------------------------------------------------------------------------
+// Automatic initialization for thread module
+// ----------------------------------------------------------------------------
+
+class wxThreadModule : public wxModule
+{
+public:
+    virtual bool OnInit();
+    virtual void OnExit();
+
+private:
+    DECLARE_DYNAMIC_CLASS(wxThreadModule)
+};
+
+IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
+
+bool wxThreadModule::OnInit()
+{
+       long response;
+       bool hasThreadManager ;
+       hasThreadManager = Gestalt( gestaltThreadMgrAttr, &response) == noErr && response & 1;
+#if !TARGET_CARBON
+#if GENERATINGCFM
+       // verify presence of shared library
+       hasThreadManager = hasThreadManager && ((Ptr)NewThread != (Ptr)kUnresolvedCFragSymbolAddress);
+#endif
+#endif
+       if ( !hasThreadManager )
+       {
+               wxMessageBox( "Error" , "Thread Support is not available on this System" , wxOK ) ;
+               return FALSE ;
+       }
+
+    // no error return for GetCurrentThreadId()
+    MacGetCurrentThread( &gs_idMainThread ) ;
+
+    return TRUE;
+}
+
+void wxThreadModule::OnExit()
 {
-    // TODO
-    return FALSE;
 }
 
-wxThread::wxThread()
+// ----------------------------------------------------------------------------
+// under MacOS we don't have currently preemptive threads, so any thread may access
+// the GUI at any time
+// ----------------------------------------------------------------------------
+
+void WXDLLEXPORT wxMutexGuiEnter()
 {
-    p_internal = new wxThreadInternal();
+}
 
-    // TODO
+void WXDLLEXPORT wxMutexGuiLeave()
+{
 }
 
-wxThread::~wxThread()
+void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
 {
-    Destroy();
-    Join();
-    delete p_internal;
 }
 
-// The default callback just joins the thread and throws away the result.
-void wxThread::OnExit()
+bool WXDLLEXPORT wxGuiOwnedByMainThread()
 {
-    Join();
+    return false ;
 }
 
-// Automatic initialization
-class wxThreadModule : public wxModule {
-  DECLARE_DYNAMIC_CLASS(wxThreadModule)
-public:
-  virtual bool OnInit() {
-    /* TODO p_mainid = GetCurrentThread(); */
-    wxMainMutex = new wxMutex();
-    wxMainMutex->Lock();
-    return TRUE;
-  }
+// wake up the main thread 
+void WXDLLEXPORT wxWakeUpMainThread()
+{
+       wxMacWakeUp() ;
+}
 
-  // Global cleanup
-  virtual void OnExit() {
-    wxMainMutex->Unlock();
-    delete wxMainMutex;
-  }
-};
+bool WXDLLEXPORT wxIsWaitingForThread()
+{
+    return false ;
+}
 
-IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
+#endif // wxUSE_THREADS