src/osx/carbon/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/osx/carbon/thread.cpp
   3 // Purpose:     wxThread Implementation
   4 // Author:      Original from Wolfram Gloger/Guilhem Lavaux/Vadim Zeitlin
   5 // Modified by: Aj Lavin, Stefan Csomor
   6 // Created:     04/22/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
   9 //                  Vadim Zeitlin (1999), Stefan Csomor (2000)
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #include "wx/wxprec.h"
  14
  15 #if defined(__BORLANDC__)
  16     #pragma hdrstop
  17 #endif
  18
  19 #ifndef WX_PRECOMP
  20     #include "wx/wx.h"
  21     #include "wx/module.h"
  22 #endif
  23
  24 #if wxUSE_THREADS
  25
  26 #include "wx/thread.h"
  27
  28 #if wxOSX_USE_COCOA_OR_CARBON
  29 #include <CoreServices/CoreServices.h>
  30 #else
  31 #include <Foundation/Foundation.h>
  32 #endif
  33
  34 #include "wx/osx/uma.h"
  35
  36 // the possible states of the thread:
  37 // ("=>" shows all possible transitions from this state)
  38 enum wxThreadState
  39 {
  40     STATE_NEW, // didn't start execution yet (=> RUNNING)
  41     STATE_RUNNING, // thread is running (=> PAUSED, CANCELED)
  42     STATE_PAUSED, // thread is temporarily suspended (=> RUNNING)
  43     STATE_CANCELED, // thread should terminate a.s.a.p. (=> EXITED)
  44     STATE_EXITED // thread is terminating
  45 };
  46
  47 // ----------------------------------------------------------------------------
  48 // globals
  49 // ----------------------------------------------------------------------------
  50
  51 // the task ID of the main thread
  52 wxThreadIdType wxThread::ms_idMainThread = kInvalidID;
  53
  54 // this is the Per-Task Storage for the pointer to the appropriate wxThread
  55 TaskStorageIndex gs_tlsForWXThread = 0;
  56
  57 // if it's false, some secondary thread is holding the GUI lock
  58 static bool gs_bGuiOwnedByMainThread = true;
  59
  60 // critical section which controls access to all GUI functions: any secondary
  61 // thread (i.e. except the main one) must enter this crit section before doing
  62 // any GUI calls
  63 static wxCriticalSection *gs_critsectGui = NULL;
  64
  65 // critical section which protects gs_nWaitingForGui variable
  66 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
  67
  68 // number of threads waiting for GUI in wxMutexGuiEnter()
  69 static size_t gs_nWaitingForGui = 0;
  70
  71 // overall number of threads, needed for determining
  72 // the sleep value of the main event loop
  73 size_t g_numberOfThreads = 0;
  74
  75
  76 #if wxUSE_GUI
  77 MPCriticalRegionID gs_guiCritical = kInvalidID;
  78 #endif
  79
  80 // ============================================================================
  81 // MacOS implementation of thread classes
  82 // ============================================================================
  83
  84 /*
  85     Notes :
  86
  87     The implementation is very close to the phtreads implementation, the reason for
  88     using MPServices is the fact that these are also available under OS 9. Thus allowing
  89     for one common API for all current builds.
  90
  91     As soon as wxThreads are on a 64 bit address space, the TLS must be extended
  92     to use two indices one for each 32 bit part as the MP implementation is limited
  93     to longs.
  94
  95     I have three implementations for mutexes :
  96     version A based on a binary semaphore, problem - not reentrant, version B based
  97     on a critical region, allows for reentrancy, performance implications not
  98     yet tested, and third a plain pthreads implementation
  99
 100     The same for condition internal, one implementation by Aj Lavin and the other one
 101     copied from the thrimpl.cpp which I assume has been more broadly tested, I've just
 102     replaced the interlock increment with the appropriate PPC calls
 103 */
 104
 105 // ----------------------------------------------------------------------------
 106 // wxCriticalSection
 107 // ----------------------------------------------------------------------------
 108
 109 wxCriticalSection::wxCriticalSection( wxCriticalSectionType WXUNUSED(critSecType) )
 110 {
 111     MPCreateCriticalRegion( (MPCriticalRegionID*) &m_critRegion );
 112 }
 113
 114 wxCriticalSection::~wxCriticalSection()
 115 {
 116     MPDeleteCriticalRegion( (MPCriticalRegionID) m_critRegion );
 117 }
 118
 119 void wxCriticalSection::Enter()
 120 {
 121     MPEnterCriticalRegion( (MPCriticalRegionID) m_critRegion, kDurationForever );
 122 }
 123
 124 void wxCriticalSection::Leave()
 125 {
 126     MPExitCriticalRegion( (MPCriticalRegionID) m_critRegion );
 127 }
 128
 129 // ----------------------------------------------------------------------------
 130 // wxMutex implementation
 131 // ----------------------------------------------------------------------------
 132
 133 #define wxUSE_MAC_SEMAPHORE_MUTEX 0
 134 #define wxUSE_MAC_CRITICAL_REGION_MUTEX 1
 135 #define wxUSE_MAC_PTHREADS_MUTEX 0
 136
 137 #if wxUSE_MAC_CRITICAL_REGION_MUTEX
 138
 139 class wxMutexInternal
 140 {
 141 public:
 142     wxMutexInternal( wxMutexType mutexType );
 143     virtual ~wxMutexInternal();
 144
 145     bool IsOk() const { return m_isOk; }
 146
 147     wxMutexError Lock() { return Lock(kDurationForever); }
 148     wxMutexError Lock(unsigned long ms);
 149     wxMutexError TryLock();
 150     wxMutexError Unlock();
 151
 152 private:
 153     MPCriticalRegionID m_critRegion;
 154     bool m_isOk ;
 155 };
 156
 157 wxMutexInternal::wxMutexInternal( wxMutexType WXUNUSED(mutexType) )
 158 {
 159     m_isOk = false;
 160     m_critRegion = kInvalidID;
 161
 162     verify_noerr( MPCreateCriticalRegion( &m_critRegion ) );
 163     m_isOk = ( m_critRegion != kInvalidID );
 164     if ( !IsOk() )
 165     {
 166         wxFAIL_MSG( wxT("Error when creating mutex") );
 167     }
 168 }
 169
 170 wxMutexInternal::~wxMutexInternal()
 171 {
 172     if ( m_critRegion != kInvalidID )
 173         MPDeleteCriticalRegion( m_critRegion );
 174
 175     MPYield();
 176 }
 177
 178 wxMutexError wxMutexInternal::Lock(unsigned long ms)
 179 {
 180     wxCHECK_MSG( m_isOk , wxMUTEX_MISC_ERROR , wxT("Invalid Mutex") );
 181
 182     OSStatus err = MPEnterCriticalRegion( m_critRegion, ms );
 183     switch ( err )
 184     {
 185         case noErr:
 186             break;
 187
 188         case kMPTimeoutErr:
 189             wxASSERT_MSG( ms != kDurationForever, wxT("unexpected timeout") );
 190             return wxMUTEX_TIMEOUT;
 191
 192         default:
 193             wxLogSysError(wxT("Could not lock mutex"));
 194             return wxMUTEX_MISC_ERROR;
 195     }
 196
 197     return wxMUTEX_NO_ERROR;
 198 }
 199
 200 wxMutexError wxMutexInternal::TryLock()
 201 {
 202     wxCHECK_MSG( m_isOk , wxMUTEX_MISC_ERROR , wxT("Invalid Mutex") ) ;
 203
 204     OSStatus err = MPEnterCriticalRegion( m_critRegion, kDurationImmediate);
 205     if (err != noErr)
 206     {
 207         if ( err == kMPTimeoutErr)
 208             return wxMUTEX_BUSY;
 209
 210         wxLogSysError( wxT("Could not try lock mutex") );
 211         return wxMUTEX_MISC_ERROR;
 212     }
 213
 214     return wxMUTEX_NO_ERROR;
 215 }
 216
 217 wxMutexError wxMutexInternal::Unlock()
 218 {
 219     wxCHECK_MSG( m_isOk , wxMUTEX_MISC_ERROR , wxT("Invalid Mutex") ) ;
 220
 221     OSStatus err = MPExitCriticalRegion( m_critRegion );
 222     MPYield() ;
 223
 224     if (err != noErr)
 225     {
 226         wxLogSysError( wxT("Could not unlock mutex") );
 227
 228         return wxMUTEX_MISC_ERROR;
 229     }
 230
 231     return wxMUTEX_NO_ERROR;
 232 }
 233
 234 #endif
 235
 236 // --------------------------------------------------------------------------
 237 // wxSemaphore
 238 // --------------------------------------------------------------------------
 239
 240 class wxSemaphoreInternal
 241 {
 242 public:
 243     wxSemaphoreInternal( int initialcount, int maxcount );
 244     virtual ~wxSemaphoreInternal();
 245
 246     bool IsOk() const
 247     { return m_isOk; }
 248
 249     wxSemaError Post();
 250     wxSemaError WaitTimeout( unsigned long milliseconds );
 251
 252     wxSemaError Wait()
 253     { return WaitTimeout( kDurationForever); }
 254
 255     wxSemaError TryWait()
 256     {
 257         wxSemaError err = WaitTimeout( kDurationImmediate );
 258         if (err == wxSEMA_TIMEOUT)
 259             err = wxSEMA_BUSY;
 260
 261         return err;
 262     }
 263
 264 private:
 265     MPSemaphoreID m_semaphore;
 266     bool m_isOk;
 267 };
 268
 269 wxSemaphoreInternal::wxSemaphoreInternal( int initialcount, int maxcount)
 270 {
 271     m_isOk = false;
 272     m_semaphore = kInvalidID;
 273     if ( maxcount == 0 )
 274         // make it practically infinite
 275         maxcount = INT_MAX;
 276
 277     verify_noerr( MPCreateSemaphore( maxcount, initialcount, &m_semaphore ) );
 278     m_isOk = ( m_semaphore != kInvalidID );
 279
 280     if ( !IsOk() )
 281     {
 282         wxFAIL_MSG( wxT("Error when creating semaphore") );
 283     }
 284 }
 285
 286 wxSemaphoreInternal::~wxSemaphoreInternal()
 287 {
 288     if (m_semaphore != kInvalidID)
 289         MPDeleteSemaphore( m_semaphore );
 290
 291     MPYield();
 292 }
 293
 294 wxSemaError wxSemaphoreInternal::WaitTimeout( unsigned long milliseconds )
 295 {
 296     OSStatus err = MPWaitOnSemaphore( m_semaphore, milliseconds );
 297     if (err != noErr)
 298     {
 299         if (err == kMPTimeoutErr)
 300             return wxSEMA_TIMEOUT;
 301
 302         return wxSEMA_MISC_ERROR;
 303     }
 304
 305     return wxSEMA_NO_ERROR;
 306 }
 307
 308 wxSemaError wxSemaphoreInternal::Post()
 309 {
 310     OSStatus err = MPSignalSemaphore( m_semaphore );
 311     MPYield();
 312     if (err != noErr)
 313         return wxSEMA_MISC_ERROR;
 314
 315     return wxSEMA_NO_ERROR;
 316 }
 317
 318 // ----------------------------------------------------------------------------
 319 // wxCondition implementation
 320 // ----------------------------------------------------------------------------
 321
 322 class wxConditionInternal
 323 {
 324 public:
 325     wxConditionInternal( wxMutex& mutex );
 326
 327     bool IsOk() const
 328     { return m_mutex.IsOk() && m_semaphore.IsOk(); }
 329
 330     wxCondError Wait();
 331     wxCondError WaitTimeout( unsigned long milliseconds );
 332
 333     wxCondError Signal();
 334     wxCondError Broadcast();
 335
 336 private:
 337     // the number of threads currently waiting for this condition
 338     SInt32 m_numWaiters;
 339
 340     // the critical section protecting m_numWaiters
 341     wxCriticalSection m_csWaiters;
 342
 343     wxMutex& m_mutex;
 344     wxSemaphore m_semaphore;
 345
 346     wxDECLARE_NO_COPY_CLASS(wxConditionInternal);
 347 };
 348
 349 wxConditionInternal::wxConditionInternal( wxMutex& mutex )
 350     : m_mutex(mutex)
 351 {
 352     // another thread can't access it until we return from ctor, so no need to
 353     // protect access to m_numWaiters here
 354     m_numWaiters = 0;
 355 }
 356
 357 wxCondError wxConditionInternal::Wait()
 358 {
 359     // increment the number of waiters
 360     IncrementAtomic( &m_numWaiters );
 361
 362     m_mutex.Unlock();
 363
 364     // a potential race condition can occur here
 365     //
 366     // after a thread increments nwaiters, and unlocks the mutex and before the
 367     // semaphore.Wait() is called, if another thread can cause a signal to be
 368     // generated
 369     //
 370     // this race condition is handled by using a semaphore and incrementing the
 371     // semaphore only if 'nwaiters' is greater that zero since the semaphore,
 372     // can 'remember' signals the race condition will not occur
 373
 374     // wait ( if necessary ) and decrement semaphore
 375     wxSemaError err = m_semaphore.Wait();
 376     m_mutex.Lock();
 377
 378     return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 379 }
 380
 381 wxCondError wxConditionInternal::WaitTimeout( unsigned long milliseconds )
 382 {
 383     IncrementAtomic( &m_numWaiters );
 384
 385     m_mutex.Unlock();
 386
 387     // a race condition can occur at this point in the code
 388     //
 389     // please see the comments in Wait(), for details
 390
 391     wxSemaError err = m_semaphore.WaitTimeout(milliseconds);
 392
 393     if ( err == wxSEMA_TIMEOUT )
 394     {
 395         // another potential race condition exists here it is caused when a
 396         // 'waiting' thread timesout, and returns from WaitForSingleObject, but
 397         // has not yet decremented 'nwaiters'.
 398         //
 399         // at this point if another thread calls signal() then the semaphore
 400         // will be incremented, but the waiting thread will miss it.
 401         //
 402         // to handle this particular case, the waiting thread calls
 403         // WaitForSingleObject again with a timeout of 0, after locking
 404         // 'nwaiters_mutex'. this call does not block because of the zero
 405         // timeout, but will allow the waiting thread to catch the missed
 406         // signals.
 407         wxCriticalSectionLocker lock(m_csWaiters);
 408
 409         err = m_semaphore.WaitTimeout(0);
 410
 411         if ( err != wxSEMA_NO_ERROR )
 412         {
 413             m_numWaiters--;
 414         }
 415     }
 416
 417     m_mutex.Lock();
 418
 419     return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 420 }
 421
 422 wxCondError wxConditionInternal::Signal()
 423 {
 424     wxCriticalSectionLocker lock(m_csWaiters);
 425
 426     if ( m_numWaiters > 0 )
 427     {
 428         // increment the semaphore by 1
 429         if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
 430             return wxCOND_MISC_ERROR;
 431
 432         m_numWaiters--;
 433     }
 434
 435     return wxCOND_NO_ERROR;
 436 }
 437
 438 wxCondError wxConditionInternal::Broadcast()
 439 {
 440     wxCriticalSectionLocker lock(m_csWaiters);
 441
 442     while ( m_numWaiters > 0 )
 443     {
 444         if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
 445             return wxCOND_MISC_ERROR;
 446
 447         m_numWaiters--;
 448     }
 449
 450     return wxCOND_NO_ERROR;
 451 }
 452
 453 // ----------------------------------------------------------------------------
 454 // wxCriticalSection implementation
 455 // ----------------------------------------------------------------------------
 456
 457 // XXX currently implemented as mutex in headers. Change to critical section.
 458
 459 // ----------------------------------------------------------------------------
 460 // wxThread implementation
 461 // ----------------------------------------------------------------------------
 462
 463 // wxThreadInternal class
 464 // ----------------------
 465
 466 class wxThreadInternal
 467 {
 468 public:
 469     wxThreadInternal()
 470     {
 471         m_tid = kInvalidID;
 472         m_state = STATE_NEW;
 473         m_prio = WXTHREAD_DEFAULT_PRIORITY;
 474         m_notifyQueueId = kInvalidID;
 475         m_exitcode = 0;
 476         m_cancelled = false ;
 477
 478         // set to true only when the thread starts waiting on m_semSuspend
 479         m_isPaused = false;
 480
 481         // defaults for joinable threads
 482         m_shouldBeJoined = true;
 483         m_isDetached = false;
 484     }
 485
 486     virtual ~wxThreadInternal()
 487     {
 488         if ( m_notifyQueueId)
 489         {
 490             MPDeleteQueue( m_notifyQueueId );
 491             m_notifyQueueId = kInvalidID ;
 492         }
 493     }
 494
 495     // thread function
 496     static OSStatus MacThreadStart(void* arg);
 497
 498     // create a new (suspended) thread (for the given thread object)
 499     bool Create(wxThread *thread, unsigned int stackSize);
 500
 501     // thread actions
 502
 503     // start the thread
 504     wxThreadError Run();
 505
 506     // unblock the thread allowing it to run
 507     void SignalRun() { m_semRun.Post(); }
 508
 509     // ask the thread to terminate
 510     void Wait();
 511
 512     // go to sleep until Resume() is called
 513     void Pause();
 514
 515     // resume the thread
 516     void Resume();
 517
 518     // accessors
 519     // priority
 520     int GetPriority() const
 521     { return m_prio; }
 522     void SetPriority(int prio);
 523
 524     // state
 525     wxThreadState GetState() const
 526     { return m_state; }
 527     void SetState(wxThreadState state)
 528     { m_state = state; }
 529
 530     // Get the ID of this thread's underlying MP Services task.
 531     MPTaskID  GetId() const
 532     { return m_tid; }
 533
 534     void SetCancelFlag()
 535     { m_cancelled = true; }
 536
 537     bool WasCancelled() const
 538     { return m_cancelled; }
 539
 540     // exit code
 541     void SetExitCode(wxThread::ExitCode exitcode)
 542     { m_exitcode = exitcode; }
 543     wxThread::ExitCode GetExitCode() const
 544     { return m_exitcode; }
 545
 546     // the pause flag
 547     void SetReallyPaused(bool paused)
 548     { m_isPaused = paused; }
 549     bool IsReallyPaused() const
 550     { return m_isPaused; }
 551
 552     // tell the thread that it is a detached one
 553     void Detach()
 554     {
 555         wxCriticalSectionLocker lock(m_csJoinFlag);
 556
 557         m_shouldBeJoined = false;
 558         m_isDetached = true;
 559     }
 560
 561 private:
 562     // the thread we're associated with
 563     wxThread *      m_thread;
 564
 565     MPTaskID        m_tid;                // thread id
 566     MPQueueID        m_notifyQueueId;    // its notification queue
 567
 568     wxThreadState m_state;              // see wxThreadState enum
 569     int           m_prio;               // in wxWidgets units: from 0 to 100
 570
 571     // this flag is set when the thread should terminate
 572     bool m_cancelled;
 573
 574     // this flag is set when the thread is blocking on m_semSuspend
 575     bool m_isPaused;
 576
 577     // the thread exit code - only used for joinable (!detached) threads and
 578     // is only valid after the thread termination
 579     wxThread::ExitCode m_exitcode;
 580
 581     // many threads may call Wait(), but only one of them should call
 582     // pthread_join(), so we have to keep track of this
 583     wxCriticalSection m_csJoinFlag;
 584     bool m_shouldBeJoined;
 585     bool m_isDetached;
 586
 587     // this semaphore is posted by Run() and the threads Entry() is not
 588     // called before it is done
 589     wxSemaphore m_semRun;
 590
 591     // this one is signaled when the thread should resume after having been
 592     // Pause()d
 593     wxSemaphore m_semSuspend;
 594 };
 595
 596 OSStatus wxThreadInternal::MacThreadStart(void *parameter)
 597 {
 598     wxThread* thread = (wxThread*) parameter ;
 599     wxThreadInternal *pthread = thread->m_internal;
 600
 601     // add to TLS so that This() will work
 602     verify_noerr( MPSetTaskStorageValue( gs_tlsForWXThread , (TaskStorageValue) thread ) ) ;
 603
 604     // have to declare this before pthread_cleanup_push() which defines a
 605     // block!
 606     bool dontRunAtAll;
 607
 608     // wait for the semaphore to be posted from Run()
 609     pthread->m_semRun.Wait();
 610
 611     // test whether we should run the run at all - may be it was deleted
 612     // before it started to Run()?
 613     {
 614         wxCriticalSectionLocker lock(thread->m_critsect);
 615
 616         dontRunAtAll = pthread->GetState() == STATE_NEW &&
 617                        pthread->WasCancelled();
 618     }
 619
 620     if ( !dontRunAtAll )
 621     {
 622         pthread->m_exitcode = thread->Entry();
 623
 624         {
 625             wxCriticalSectionLocker lock(thread->m_critsect);
 626             pthread->SetState( STATE_EXITED );
 627         }
 628     }
 629
 630     if ( dontRunAtAll )
 631     {
 632         if ( pthread->m_isDetached )
 633             delete thread;
 634
 635         return -1;
 636     }
 637     else
 638     {
 639         // on Mac for the running code,
 640         // the correct thread termination is to return
 641
 642         // terminate the thread
 643         thread->Exit( pthread->m_exitcode );
 644
 645         return (OSStatus) NULL; // pthread->m_exitcode;
 646     }
 647 }
 648
 649 bool wxThreadInternal::Create( wxThread *thread, unsigned int stackSize )
 650 {
 651     wxASSERT_MSG( m_state == STATE_NEW && !m_tid,
 652                     wxT("Create()ing thread twice?") );
 653
 654     OSStatus err = noErr;
 655     m_thread = thread;
 656
 657     if ( m_notifyQueueId == kInvalidID )
 658     {
 659         OSStatus err = MPCreateQueue( &m_notifyQueueId );
 660         if (err != noErr)
 661         {
 662             wxLogSysError( wxT("Cant create the thread event queue") );
 663
 664             return false;
 665         }
 666     }
 667
 668     m_state = STATE_NEW;
 669
 670     err = MPCreateTask(
 671         MacThreadStart, (void*)m_thread, stackSize,
 672         m_notifyQueueId, &m_exitcode, 0, 0, &m_tid );
 673
 674     if (err != noErr)
 675     {
 676         wxLogSysError( wxT("Can't create thread") );
 677
 678         return false;
 679     }
 680
 681     if ( m_prio != WXTHREAD_DEFAULT_PRIORITY )
 682         SetPriority( m_prio );
 683
 684     return true;
 685 }
 686
 687 void wxThreadInternal::SetPriority( int priority )
 688 {
 689     m_prio = priority;
 690
 691     if (m_tid)
 692     {
 693         // Mac priorities range from 1 to 10,000, with a default of 100.
 694         // wxWidgets priorities range from 0 to 100 with a default of 50.
 695         // We can map wxWidgets to Mac priorities easily by assuming
 696         // the former uses a logarithmic scale.
 697         const unsigned int macPriority = (int)( exp( priority / 25.0 * log( 10.0)) + 0.5);
 698
 699         MPSetTaskWeight( m_tid, macPriority );
 700     }
 701 }
 702
 703 wxThreadError wxThreadInternal::Run()
 704 {
 705     wxCHECK_MSG( GetState() == STATE_NEW, wxTHREAD_RUNNING,
 706                  wxT("thread may only be started once after Create()") );
 707
 708     SetState( STATE_RUNNING );
 709
 710     // wake up threads waiting for our start
 711     SignalRun();
 712
 713     return wxTHREAD_NO_ERROR;
 714 }
 715
 716 void wxThreadInternal::Wait()
 717 {
 718    wxCHECK_RET( !m_isDetached, wxT("can't wait for a detached thread") );
 719
 720     // if the thread we're waiting for is waiting for the GUI mutex, we will
 721     // deadlock so make sure we release it temporarily
 722     if ( wxThread::IsMain() )
 723     {
 724         // give the thread we're waiting for chance to do the GUI call
 725         // it might be in, we don't do this conditionally as the to be waited on
 726         // thread might have to acquire the mutex later but before terminating
 727         if ( wxGuiOwnedByMainThread() )
 728             wxMutexGuiLeave();
 729     }
 730
 731     {
 732         wxCriticalSectionLocker lock(m_csJoinFlag);
 733
 734         if ( m_shouldBeJoined )
 735         {
 736             void *param1, *param2, *rc;
 737
 738             OSStatus err = MPWaitOnQueue(
 739                 m_notifyQueueId,
 740                 &param1,
 741                 &param2,
 742                 &rc,
 743                 kDurationForever );
 744             if (err != noErr)
 745             {
 746                 wxLogSysError( wxT( "Cannot wait for thread termination."));
 747                 rc = (void*) -1;
 748             }
 749
 750             // actually param1 would be the address of m_exitcode
 751             // but we don't need this here
 752             m_exitcode = rc;
 753
 754             m_shouldBeJoined = false;
 755         }
 756     }
 757 }
 758
 759 void wxThreadInternal::Pause()
 760 {
 761     // the state is set from the thread which pauses us first, this function
 762     // is called later so the state should have been already set
 763     wxCHECK_RET( m_state == STATE_PAUSED,
 764                  wxT("thread must first be paused with wxThread::Pause().") );
 765
 766     // wait until the semaphore is Post()ed from Resume()
 767     m_semSuspend.Wait();
 768 }
 769
 770 void wxThreadInternal::Resume()
 771 {
 772     wxCHECK_RET( m_state == STATE_PAUSED,
 773                  wxT("can't resume thread which is not suspended.") );
 774
 775     // the thread might be not actually paused yet - if there were no call to
 776     // TestDestroy() since the last call to Pause() for example
 777     if ( IsReallyPaused() )
 778     {
 779         // wake up Pause()
 780         m_semSuspend.Post();
 781
 782         // reset the flag
 783         SetReallyPaused( false );
 784     }
 785
 786     SetState( STATE_RUNNING );
 787 }
 788
 789 // static functions
 790 // ----------------
 791
 792 wxThread *wxThread::This()
 793 {
 794     wxThread* thr = (wxThread*) MPGetTaskStorageValue( gs_tlsForWXThread ) ;
 795
 796     return thr;
 797 }
 798
 799 #ifdef Yield
 800 #undef Yield
 801 #endif
 802
 803 void wxThread::Yield()
 804 {
 805     CFRunLoopRunInMode( kCFRunLoopDefaultMode , 0 , true ) ;
 806
 807     MPYield();
 808 }
 809
 810 void wxThread::Sleep( unsigned long milliseconds )
 811 {
 812     AbsoluteTime wakeup = AddDurationToAbsolute( milliseconds, UpTime() );
 813     MPDelayUntil( &wakeup );
 814 }
 815
 816 int wxThread::GetCPUCount()
 817 {
 818     return MPProcessors();
 819 }
 820
 821 unsigned long wxThread::GetCurrentId()
 822 {
 823     return (unsigned long)MPCurrentTaskID();
 824 }
 825
 826 bool wxThread::SetConcurrency( size_t WXUNUSED(level) )
 827 {
 828     // Cannot be set in MacOS.
 829     return false;
 830 }
 831
 832 wxThread::wxThread( wxThreadKind kind )
 833 {
 834     g_numberOfThreads++;
 835     m_internal = new wxThreadInternal();
 836
 837     m_isDetached = (kind == wxTHREAD_DETACHED);
 838 }
 839
 840 wxThread::~wxThread()
 841 {
 842     wxASSERT_MSG( g_numberOfThreads>0 , wxT("More threads deleted than created.") ) ;
 843
 844     g_numberOfThreads--;
 845
 846     m_critsect.Enter();
 847
 848     // check that the thread either exited or couldn't be created
 849     if ( m_internal->GetState() != STATE_EXITED &&
 850          m_internal->GetState() != STATE_NEW )
 851     {
 852         wxLogDebug(
 853             wxT("The thread %ld is being destroyed although it is still running! The application may crash."),
 854             GetId() );
 855     }
 856
 857     m_critsect.Leave();
 858
 859     wxDELETE( m_internal ) ;
 860 }
 861
 862 wxThreadError wxThread::Create( unsigned int stackSize )
 863 {
 864     wxCriticalSectionLocker lock(m_critsect);
 865
 866     if ( m_isDetached )
 867         m_internal->Detach() ;
 868
 869     if ( !m_internal->Create(this, stackSize) )
 870     {
 871         m_internal->SetState( STATE_EXITED );
 872
 873         return wxTHREAD_NO_RESOURCE;
 874     }
 875
 876     return wxTHREAD_NO_ERROR;
 877 }
 878
 879 wxThreadError wxThread::Run()
 880 {
 881     wxCriticalSectionLocker lock(m_critsect);
 882
 883     wxCHECK_MSG( m_internal->GetId(), wxTHREAD_MISC_ERROR,
 884                  wxT("must call wxThread::Create() first") );
 885
 886     return m_internal->Run();
 887 }
 888
 889 // -----------------------------------------------------------------------------
 890 // pause/resume
 891 // -----------------------------------------------------------------------------
 892
 893 wxThreadError wxThread::Pause()
 894 {
 895     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
 896                  wxT("a thread can't pause itself") );
 897
 898     wxCriticalSectionLocker lock(m_critsect);
 899
 900     if ( m_internal->GetState() != STATE_RUNNING )
 901     {
 902         wxLogDebug( wxT("Can't pause thread which is not running.") );
 903
 904         return wxTHREAD_NOT_RUNNING;
 905     }
 906
 907     // just set a flag, the thread will be really paused only during the next
 908     // call to TestDestroy()
 909     m_internal->SetState( STATE_PAUSED );
 910
 911     return wxTHREAD_NO_ERROR;
 912 }
 913
 914 wxThreadError wxThread::Resume()
 915 {
 916     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
 917                  wxT("a thread can't resume itself") );
 918
 919     wxCriticalSectionLocker lock(m_critsect);
 920
 921     wxThreadState state = m_internal->GetState();
 922
 923     switch ( state )
 924     {
 925         case STATE_PAUSED:
 926             m_internal->Resume();
 927             return wxTHREAD_NO_ERROR;
 928
 929         case STATE_EXITED:
 930             return wxTHREAD_NO_ERROR;
 931
 932         default:
 933             wxLogDebug( wxT("Attempt to resume a thread which is not paused.") );
 934
 935             return wxTHREAD_MISC_ERROR;
 936     }
 937 }
 938
 939 // -----------------------------------------------------------------------------
 940 // exiting thread
 941 // -----------------------------------------------------------------------------
 942
 943 wxThread::ExitCode wxThread::Wait(wxThreadWait WXUNUSED(waitMode))
 944 {
 945     wxCHECK_MSG( This() != this, (ExitCode)-1,
 946                  wxT("a thread can't wait for itself") );
 947
 948     wxCHECK_MSG( !m_isDetached, (ExitCode)-1,
 949                  wxT("can't wait for detached thread") );
 950
 951     m_internal->Wait();
 952
 953     return m_internal->GetExitCode();
 954 }
 955
 956 wxThreadError wxThread::Delete(ExitCode *rc, wxThreadWait WXUNUSED(waitMode))
 957 {
 958     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
 959                  wxT("a thread can't delete itself") );
 960
 961     bool isDetached = m_isDetached;
 962
 963     m_critsect.Enter();
 964     wxThreadState state = m_internal->GetState();
 965
 966     // ask the thread to stop
 967     m_internal->SetCancelFlag();
 968
 969     m_critsect.Leave();
 970
 971     switch ( state )
 972     {
 973         case STATE_NEW:
 974             // we need to wake up the thread so that PthreadStart() will
 975             // terminate - right now it's blocking on run semaphore in
 976             // PthreadStart()
 977             m_internal->SignalRun();
 978
 979             // fall through
 980
 981         case STATE_EXITED:
 982             // nothing to do
 983             break;
 984
 985         case STATE_PAUSED:
 986             // resume the thread first
 987             m_internal->Resume();
 988
 989             // fall through
 990
 991         default:
 992             if ( !isDetached )
 993             {
 994                 // wait until the thread stops
 995                 m_internal->Wait();
 996
 997                 if ( rc )
 998                 {
 999                     // return the exit code of the thread
1000                     *rc = m_internal->GetExitCode();
1001                 }
1002             }
1003     }
1004
1005     return wxTHREAD_NO_ERROR;
1006 }
1007
1008 wxThreadError wxThread::Kill()
1009 {
1010     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
1011                  wxT("a thread can't kill itself") );
1012
1013     switch ( m_internal->GetState() )
1014     {
1015         case STATE_NEW:
1016         case STATE_EXITED:
1017             return wxTHREAD_NOT_RUNNING;
1018
1019         case STATE_PAUSED:
1020             // resume the thread first
1021             Resume();
1022
1023             // fall through
1024
1025         default:
1026             OSStatus err = MPTerminateTask( m_internal->GetId() , -1 ) ;
1027             if (err != noErr)
1028             {
1029                 wxLogError( wxT("Failed to terminate a thread.") );
1030
1031                 return wxTHREAD_MISC_ERROR;
1032             }
1033
1034             if ( m_isDetached )
1035             {
1036                 delete this ;
1037             }
1038             else
1039             {
1040                 // this should be retrieved by Wait actually
1041                 m_internal->SetExitCode( (void*)-1 );
1042             }
1043
1044             return wxTHREAD_NO_ERROR;
1045     }
1046 }
1047
1048 void wxThread::Exit( ExitCode status )
1049 {
1050     wxASSERT_MSG( This() == this,
1051                   wxT("wxThread::Exit() can only be called in the context of the same thread") );
1052
1053     // don't enter m_critsect before calling OnExit() because the user code
1054     // might deadlock if, for example, it signals a condition in OnExit() (a
1055     // common case) while the main thread calls any of functions entering
1056     // m_critsect on us (almost all of them do)
1057     OnExit();
1058
1059     MPTaskID threadid = m_internal->GetId();
1060
1061     if ( IsDetached() )
1062     {
1063         delete this;
1064     }
1065     else // joinable
1066     {
1067         // update the status of the joinable thread
1068         wxCriticalSectionLocker lock( m_critsect );
1069         m_internal->SetState( STATE_EXITED );
1070     }
1071
1072     MPTerminateTask( threadid, (long)status );
1073 }
1074
1075 // also test whether we were paused
1076 bool wxThread::TestDestroy()
1077 {
1078     wxASSERT_MSG( This() == this,
1079                   wxT("wxThread::TestDestroy() can only be called in the context of the same thread") );
1080
1081     m_critsect.Enter();
1082
1083     if ( m_internal->GetState() == STATE_PAUSED )
1084     {
1085         m_internal->SetReallyPaused( true );
1086
1087         // leave the crit section or the other threads will stop too if they attempt
1088         // to call any of (seemingly harmless) IsXXX() functions while we sleep
1089         m_critsect.Leave();
1090
1091         m_internal->Pause();
1092     }
1093     else
1094     {
1095         // thread wasn't requested to pause, nothing to do
1096         m_critsect.Leave();
1097     }
1098
1099     return m_internal->WasCancelled();
1100 }
1101
1102 // -----------------------------------------------------------------------------
1103 // priority setting
1104 // -----------------------------------------------------------------------------
1105
1106 void wxThread::SetPriority(unsigned int prio)
1107 {
1108     wxCHECK_RET( ((int)WXTHREAD_MIN_PRIORITY <= (int)prio) &&
1109                  ((int)prio <= (int)WXTHREAD_MAX_PRIORITY),
1110                  wxT("invalid thread priority") );
1111
1112     wxCriticalSectionLocker lock(m_critsect);
1113
1114     switch ( m_internal->GetState() )
1115     {
1116         case STATE_RUNNING:
1117         case STATE_PAUSED:
1118         case STATE_NEW:
1119             // thread not yet started, priority will be set when it is
1120             m_internal->SetPriority( prio );
1121             break;
1122
1123         case STATE_EXITED:
1124         default:
1125             wxFAIL_MSG( wxT("impossible to set thread priority in this state") );
1126     }
1127 }
1128
1129 unsigned int wxThread::GetPriority() const
1130 {
1131     wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
1132
1133     return m_internal->GetPriority();
1134 }
1135
1136 unsigned long wxThread::GetId() const
1137 {
1138     wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
1139
1140     return (unsigned long)m_internal->GetId();
1141 }
1142
1143 // -----------------------------------------------------------------------------
1144 // state tests
1145 // -----------------------------------------------------------------------------
1146
1147 bool wxThread::IsRunning() const
1148 {
1149     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
1150
1151     return m_internal->GetState() == STATE_RUNNING;
1152 }
1153
1154 bool wxThread::IsAlive() const
1155 {
1156     wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
1157
1158     switch ( m_internal->GetState() )
1159     {
1160         case STATE_RUNNING:
1161         case STATE_PAUSED:
1162             return true;
1163
1164         default:
1165             return false;
1166     }
1167 }
1168
1169 bool wxThread::IsPaused() const
1170 {
1171     wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
1172
1173     return (m_internal->GetState() == STATE_PAUSED);
1174 }
1175
1176 // ----------------------------------------------------------------------------
1177 // Automatic initialization for thread module
1178 // ----------------------------------------------------------------------------
1179
1180 class wxThreadModule : public wxModule
1181 {
1182 public:
1183     virtual bool OnInit();
1184     virtual void OnExit();
1185
1186 private:
1187     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1188 };
1189
1190 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1191
1192 bool wxThreadModule::OnInit()
1193 {
1194     bool hasThreadManager =
1195 #ifdef __LP64__
1196         true ; // TODO VERIFY IN NEXT BUILD
1197 #else
1198         MPLibraryIsLoaded();
1199 #endif
1200
1201     if ( !hasThreadManager )
1202     {
1203         wxLogError( wxT("MP thread support is not available on this system" ) ) ;
1204
1205         return false;
1206     }
1207
1208     // main thread's This() is NULL
1209     verify_noerr( MPAllocateTaskStorageIndex( &gs_tlsForWXThread ) ) ;
1210     verify_noerr( MPSetTaskStorageValue( gs_tlsForWXThread, 0 ) ) ;
1211
1212     wxThread::ms_idMainThread = wxThread::GetCurrentId();
1213     gs_critsectWaitingForGui = new wxCriticalSection();
1214
1215     gs_critsectGui = new wxCriticalSection();
1216     gs_critsectGui->Enter();
1217
1218     return true;
1219 }
1220
1221 void wxThreadModule::OnExit()
1222 {
1223     if ( gs_critsectGui )
1224     {
1225         if ( !wxGuiOwnedByMainThread() )
1226         {
1227             gs_critsectGui->Enter();
1228             gs_bGuiOwnedByMainThread = true;
1229         }
1230
1231         gs_critsectGui->Leave();
1232         wxDELETE(gs_critsectGui);
1233     }
1234
1235     wxDELETE(gs_critsectWaitingForGui);
1236 }
1237
1238 // ----------------------------------------------------------------------------
1239 // GUI Serialization copied from MSW implementation
1240 // ----------------------------------------------------------------------------
1241
1242 void wxMutexGuiEnterImpl()
1243 {
1244     // this would dead lock everything...
1245     wxASSERT_MSG( !wxThread::IsMain(),
1246                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1247
1248     // the order in which we enter the critical sections here is crucial!!
1249
1250     // set the flag telling to the main thread that we want to do some GUI
1251     {
1252         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1253
1254         gs_nWaitingForGui++;
1255     }
1256
1257     wxWakeUpMainThread();
1258
1259     // now we may block here because the main thread will soon let us in
1260     // (during the next iteration of OnIdle())
1261     gs_critsectGui->Enter();
1262 }
1263
1264 void wxMutexGuiLeaveImpl()
1265 {
1266     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1267
1268     if ( wxThread::IsMain() )
1269     {
1270         gs_bGuiOwnedByMainThread = false;
1271     }
1272     else
1273     {
1274         // decrement the number of threads waiting for GUI access now
1275         wxASSERT_MSG( gs_nWaitingForGui > 0,
1276                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1277
1278         gs_nWaitingForGui--;
1279
1280         wxWakeUpMainThread();
1281     }
1282
1283     gs_critsectGui->Leave();
1284 }
1285
1286 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1287 {
1288     wxASSERT_MSG( wxThread::IsMain(),
1289                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1290
1291     if ( !gs_critsectWaitingForGui )
1292         return;
1293
1294     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1295
1296     if ( gs_nWaitingForGui == 0 )
1297     {
1298         // no threads are waiting for GUI - so we may acquire the lock without
1299         // any danger (but only if we don't already have it)
1300         if ( !wxGuiOwnedByMainThread() )
1301         {
1302             gs_critsectGui->Enter();
1303
1304             gs_bGuiOwnedByMainThread = true;
1305         }
1306         //else: already have it, nothing to do
1307     }
1308     else
1309     {
1310         // some threads are waiting, release the GUI lock if we have it
1311         if ( wxGuiOwnedByMainThread() )
1312             wxMutexGuiLeave();
1313         //else: some other worker thread is doing GUI
1314     }
1315 }
1316
1317 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1318 {
1319     return gs_bGuiOwnedByMainThread;
1320 }
1321
1322 // wake up the main thread
1323 void WXDLLEXPORT wxWakeUpMainThread()
1324 {
1325     wxMacWakeUp();
1326 }
1327
1328 // ----------------------------------------------------------------------------
1329 // include common implementation code
1330 // ----------------------------------------------------------------------------
1331
1332 #include "wx/thrimpl.cpp"
1333
1334 #endif // wxUSE_THREADS