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 // Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
   8 //                  Vadim Zeitlin (1999), Stefan Csomor (2000)
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #include "wx/wxprec.h"
  13
  14 #if defined(__BORLANDC__)
  15     #pragma hdrstop
  16 #endif
  17
  18 #ifndef WX_PRECOMP
  19     #include "wx/wx.h"
  20     #include "wx/module.h"
  21 #endif
  22
  23 #if wxUSE_THREADS
  24
  25 #include "wx/thread.h"
  26
  27 #if wxOSX_USE_COCOA_OR_CARBON
  28 #include <CoreServices/CoreServices.h>
  29 #else
  30 #include <Foundation/Foundation.h>
  31 #endif
  32
  33 #include "wx/osx/uma.h"
  34
  35 // the possible states of the thread:
  36 // ("=>" shows all possible transitions from this state)
  37 enum wxThreadState
  38 {
  39     STATE_NEW, // didn't start execution yet (=> RUNNING)
  40     STATE_RUNNING, // thread is running (=> PAUSED, CANCELED)
  41     STATE_PAUSED, // thread is temporarily suspended (=> RUNNING)
  42     STATE_CANCELED, // thread should terminate a.s.a.p. (=> EXITED)
  43     STATE_EXITED // thread is terminating
  44 };
  45
  46 // ----------------------------------------------------------------------------
  47 // globals
  48 // ----------------------------------------------------------------------------
  49
  50 // the task ID of the main thread
  51 wxThreadIdType wxThread::ms_idMainThread = kInvalidID;
  52
  53 // this is the Per-Task Storage for the pointer to the appropriate wxThread
  54 TaskStorageIndex gs_tlsForWXThread = 0;
  55
  56 // if it's false, some secondary thread is holding the GUI lock
  57 static bool gs_bGuiOwnedByMainThread = true;
  58
  59 // critical section which controls access to all GUI functions: any secondary
  60 // thread (i.e. except the main one) must enter this crit section before doing
  61 // any GUI calls
  62 static wxCriticalSection *gs_critsectGui = NULL;
  63
  64 // critical section which protects gs_nWaitingForGui variable
  65 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
  66
  67 // number of threads waiting for GUI in wxMutexGuiEnter()
  68 static size_t gs_nWaitingForGui = 0;
  69
  70 // overall number of threads, needed for determining
  71 // the sleep value of the main event loop
  72 size_t g_numberOfThreads = 0;
  73
  74
  75 #if wxUSE_GUI
  76 MPCriticalRegionID gs_guiCritical = kInvalidID;
  77 #endif
  78
  79 // ============================================================================
  80 // MacOS implementation of thread classes
  81 // ============================================================================
  82
  83 /*
  84     Notes :
  85
  86     The implementation is very close to the phtreads implementation, the reason for
  87     using MPServices is the fact that these are also available under OS 9. Thus allowing
  88     for one common API for all current builds.
  89
  90     As soon as wxThreads are on a 64 bit address space, the TLS must be extended
  91     to use two indices one for each 32 bit part as the MP implementation is limited
  92     to longs.
  93
  94     I have three implementations for mutexes :
  95     version A based on a binary semaphore, problem - not reentrant, version B based
  96     on a critical region, allows for reentrancy, performance implications not
  97     yet tested, and third a plain pthreads implementation
  98
  99     The same for condition internal, one implementation by Aj Lavin and the other one
 100     copied from the thrimpl.cpp which I assume has been more broadly tested, I've just
 101     replaced the interlock increment with the appropriate PPC calls
 102 */
 103
 104 // ----------------------------------------------------------------------------
 105 // wxCriticalSection
 106 // ----------------------------------------------------------------------------
 107
 108 wxCriticalSection::wxCriticalSection( wxCriticalSectionType WXUNUSED(critSecType) )
 109 {
 110     MPCreateCriticalRegion( (MPCriticalRegionID*) &m_critRegion );
 111 }
 112
 113 wxCriticalSection::~wxCriticalSection()
 114 {
 115     MPDeleteCriticalRegion( (MPCriticalRegionID) m_critRegion );
 116 }
 117
 118 void wxCriticalSection::Enter()
 119 {
 120     MPEnterCriticalRegion( (MPCriticalRegionID) m_critRegion, kDurationForever );
 121 }
 122
 123 bool wxCriticalSection::TryEnter()
 124 {
 125     return MPEnterCriticalRegion( (MPCriticalRegionID) m_critRegion, kDurationImmediate ) == noErr;
 126 }
 127
 128 void wxCriticalSection::Leave()
 129 {
 130     MPExitCriticalRegion( (MPCriticalRegionID) m_critRegion );
 131 }
 132
 133 // ----------------------------------------------------------------------------
 134 // wxMutex implementation
 135 // ----------------------------------------------------------------------------
 136
 137 #define wxUSE_MAC_SEMAPHORE_MUTEX 0
 138 #define wxUSE_MAC_CRITICAL_REGION_MUTEX 1
 139 #define wxUSE_MAC_PTHREADS_MUTEX 0
 140
 141 #if wxUSE_MAC_CRITICAL_REGION_MUTEX
 142
 143 class wxMutexInternal
 144 {
 145 public:
 146     wxMutexInternal( wxMutexType mutexType );
 147     virtual ~wxMutexInternal();
 148
 149     bool IsOk() const { return m_isOk; }
 150
 151     wxMutexError Lock() { return Lock(kDurationForever); }
 152     wxMutexError Lock(unsigned long ms);
 153     wxMutexError TryLock();
 154     wxMutexError Unlock();
 155
 156 private:
 157     MPCriticalRegionID m_critRegion;
 158     bool m_isOk ;
 159 };
 160
 161 wxMutexInternal::wxMutexInternal( wxMutexType WXUNUSED(mutexType) )
 162 {
 163     m_isOk = false;
 164     m_critRegion = kInvalidID;
 165
 166     verify_noerr( MPCreateCriticalRegion( &m_critRegion ) );
 167     m_isOk = ( m_critRegion != kInvalidID );
 168     if ( !IsOk() )
 169     {
 170         wxFAIL_MSG( wxT("Error when creating mutex") );
 171     }
 172 }
 173
 174 wxMutexInternal::~wxMutexInternal()
 175 {
 176     if ( m_critRegion != kInvalidID )
 177         MPDeleteCriticalRegion( m_critRegion );
 178
 179     MPYield();
 180 }
 181
 182 wxMutexError wxMutexInternal::Lock(unsigned long ms)
 183 {
 184     wxCHECK_MSG( m_isOk , wxMUTEX_MISC_ERROR , wxT("Invalid Mutex") );
 185
 186     OSStatus err = MPEnterCriticalRegion( m_critRegion, ms );
 187     switch ( err )
 188     {
 189         case noErr:
 190             break;
 191
 192         case kMPTimeoutErr:
 193             wxASSERT_MSG( ms != kDurationForever, wxT("unexpected timeout") );
 194             return wxMUTEX_TIMEOUT;
 195
 196         default:
 197             wxLogSysError(wxT("Could not lock mutex"));
 198             return wxMUTEX_MISC_ERROR;
 199     }
 200
 201     return wxMUTEX_NO_ERROR;
 202 }
 203
 204 wxMutexError wxMutexInternal::TryLock()
 205 {
 206     wxCHECK_MSG( m_isOk , wxMUTEX_MISC_ERROR , wxT("Invalid Mutex") ) ;
 207
 208     OSStatus err = MPEnterCriticalRegion( m_critRegion, kDurationImmediate);
 209     if (err != noErr)
 210     {
 211         if ( err == kMPTimeoutErr)
 212             return wxMUTEX_BUSY;
 213
 214         wxLogSysError( wxT("Could not try lock mutex") );
 215         return wxMUTEX_MISC_ERROR;
 216     }
 217
 218     return wxMUTEX_NO_ERROR;
 219 }
 220
 221 wxMutexError wxMutexInternal::Unlock()
 222 {
 223     wxCHECK_MSG( m_isOk , wxMUTEX_MISC_ERROR , wxT("Invalid Mutex") ) ;
 224
 225     OSStatus err = MPExitCriticalRegion( m_critRegion );
 226     MPYield() ;
 227
 228     if (err != noErr)
 229     {
 230         wxLogSysError( wxT("Could not unlock mutex") );
 231
 232         return wxMUTEX_MISC_ERROR;
 233     }
 234
 235     return wxMUTEX_NO_ERROR;
 236 }
 237
 238 #endif
 239
 240 // --------------------------------------------------------------------------
 241 // wxSemaphore
 242 // --------------------------------------------------------------------------
 243
 244 class wxSemaphoreInternal
 245 {
 246 public:
 247     wxSemaphoreInternal( int initialcount, int maxcount );
 248     virtual ~wxSemaphoreInternal();
 249
 250     bool IsOk() const
 251     { return m_isOk; }
 252
 253     wxSemaError Post();
 254     wxSemaError WaitTimeout( unsigned long milliseconds );
 255
 256     wxSemaError Wait()
 257     { return WaitTimeout( kDurationForever); }
 258
 259     wxSemaError TryWait()
 260     {
 261         wxSemaError err = WaitTimeout( kDurationImmediate );
 262         if (err == wxSEMA_TIMEOUT)
 263             err = wxSEMA_BUSY;
 264
 265         return err;
 266     }
 267
 268 private:
 269     MPSemaphoreID m_semaphore;
 270     bool m_isOk;
 271 };
 272
 273 wxSemaphoreInternal::wxSemaphoreInternal( int initialcount, int maxcount)
 274 {
 275     m_isOk = false;
 276     m_semaphore = kInvalidID;
 277     if ( maxcount == 0 )
 278         // make it practically infinite
 279         maxcount = INT_MAX;
 280
 281     verify_noerr( MPCreateSemaphore( maxcount, initialcount, &m_semaphore ) );
 282     m_isOk = ( m_semaphore != kInvalidID );
 283
 284     if ( !IsOk() )
 285     {
 286         wxFAIL_MSG( wxT("Error when creating semaphore") );
 287     }
 288 }
 289
 290 wxSemaphoreInternal::~wxSemaphoreInternal()
 291 {
 292     if (m_semaphore != kInvalidID)
 293         MPDeleteSemaphore( m_semaphore );
 294
 295     MPYield();
 296 }
 297
 298 wxSemaError wxSemaphoreInternal::WaitTimeout( unsigned long milliseconds )
 299 {
 300     OSStatus err = MPWaitOnSemaphore( m_semaphore, milliseconds );
 301     if (err != noErr)
 302     {
 303         if (err == kMPTimeoutErr)
 304             return wxSEMA_TIMEOUT;
 305
 306         return wxSEMA_MISC_ERROR;
 307     }
 308
 309     return wxSEMA_NO_ERROR;
 310 }
 311
 312 wxSemaError wxSemaphoreInternal::Post()
 313 {
 314     OSStatus err = MPSignalSemaphore( m_semaphore );
 315     MPYield();
 316     if (err != noErr)
 317         return wxSEMA_MISC_ERROR;
 318
 319     return wxSEMA_NO_ERROR;
 320 }
 321
 322 // ----------------------------------------------------------------------------
 323 // wxCondition implementation
 324 // ----------------------------------------------------------------------------
 325
 326 class wxConditionInternal
 327 {
 328 public:
 329     wxConditionInternal( wxMutex& mutex );
 330
 331     bool IsOk() const
 332     { return m_mutex.IsOk() && m_semaphore.IsOk(); }
 333
 334     wxCondError Wait();
 335     wxCondError WaitTimeout( unsigned long milliseconds );
 336
 337     wxCondError Signal();
 338     wxCondError Broadcast();
 339
 340 private:
 341     // the number of threads currently waiting for this condition
 342     SInt32 m_numWaiters;
 343
 344     // the critical section protecting m_numWaiters
 345     wxCriticalSection m_csWaiters;
 346
 347     wxMutex& m_mutex;
 348     wxSemaphore m_semaphore;
 349
 350     wxDECLARE_NO_COPY_CLASS(wxConditionInternal);
 351 };
 352
 353 wxConditionInternal::wxConditionInternal( wxMutex& mutex )
 354     : m_mutex(mutex)
 355 {
 356     // another thread can't access it until we return from ctor, so no need to
 357     // protect access to m_numWaiters here
 358     m_numWaiters = 0;
 359 }
 360
 361 wxCondError wxConditionInternal::Wait()
 362 {
 363     // increment the number of waiters
 364     IncrementAtomic( &m_numWaiters );
 365
 366     m_mutex.Unlock();
 367
 368     // a potential race condition can occur here
 369     //
 370     // after a thread increments nwaiters, and unlocks the mutex and before the
 371     // semaphore.Wait() is called, if another thread can cause a signal to be
 372     // generated
 373     //
 374     // this race condition is handled by using a semaphore and incrementing the
 375     // semaphore only if 'nwaiters' is greater that zero since the semaphore,
 376     // can 'remember' signals the race condition will not occur
 377
 378     // wait ( if necessary ) and decrement semaphore
 379     wxSemaError err = m_semaphore.Wait();
 380     m_mutex.Lock();
 381
 382     return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 383 }
 384
 385 wxCondError wxConditionInternal::WaitTimeout( unsigned long milliseconds )
 386 {
 387     IncrementAtomic( &m_numWaiters );
 388
 389     m_mutex.Unlock();
 390
 391     // a race condition can occur at this point in the code
 392     //
 393     // please see the comments in Wait(), for details
 394
 395     wxSemaError err = m_semaphore.WaitTimeout(milliseconds);
 396
 397     if ( err == wxSEMA_TIMEOUT )
 398     {
 399         // another potential race condition exists here it is caused when a
 400         // 'waiting' thread timesout, and returns from WaitForSingleObject, but
 401         // has not yet decremented 'nwaiters'.
 402         //
 403         // at this point if another thread calls signal() then the semaphore
 404         // will be incremented, but the waiting thread will miss it.
 405         //
 406         // to handle this particular case, the waiting thread calls
 407         // WaitForSingleObject again with a timeout of 0, after locking
 408         // 'nwaiters_mutex'. this call does not block because of the zero
 409         // timeout, but will allow the waiting thread to catch the missed
 410         // signals.
 411         wxCriticalSectionLocker lock(m_csWaiters);
 412
 413         err = m_semaphore.WaitTimeout(0);
 414
 415         if ( err != wxSEMA_NO_ERROR )
 416         {
 417             m_numWaiters--;
 418         }
 419     }
 420
 421     m_mutex.Lock();
 422
 423     return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 424 }
 425
 426 wxCondError wxConditionInternal::Signal()
 427 {
 428     wxCriticalSectionLocker lock(m_csWaiters);
 429
 430     if ( m_numWaiters > 0 )
 431     {
 432         // increment the semaphore by 1
 433         if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
 434             return wxCOND_MISC_ERROR;
 435
 436         m_numWaiters--;
 437     }
 438
 439     return wxCOND_NO_ERROR;
 440 }
 441
 442 wxCondError wxConditionInternal::Broadcast()
 443 {
 444     wxCriticalSectionLocker lock(m_csWaiters);
 445
 446     while ( m_numWaiters > 0 )
 447     {
 448         if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
 449             return wxCOND_MISC_ERROR;
 450
 451         m_numWaiters--;
 452     }
 453
 454     return wxCOND_NO_ERROR;
 455 }
 456
 457 // ----------------------------------------------------------------------------
 458 // wxCriticalSection implementation
 459 // ----------------------------------------------------------------------------
 460
 461 // XXX currently implemented as mutex in headers. Change to critical section.
 462
 463 // ----------------------------------------------------------------------------
 464 // wxThread implementation
 465 // ----------------------------------------------------------------------------
 466
 467 // wxThreadInternal class
 468 // ----------------------
 469
 470 class wxThreadInternal
 471 {
 472 public:
 473     wxThreadInternal()
 474     {
 475         m_tid = kInvalidID;
 476         m_state = STATE_NEW;
 477         m_prio = wxPRIORITY_DEFAULT;
 478         m_notifyQueueId = kInvalidID;
 479         m_exitcode = 0;
 480         m_cancelled = false ;
 481
 482         // set to true only when the thread starts waiting on m_semSuspend
 483         m_isPaused = false;
 484
 485         // defaults for joinable threads
 486         m_shouldBeJoined = true;
 487         m_isDetached = false;
 488     }
 489
 490     virtual ~wxThreadInternal()
 491     {
 492         if ( m_notifyQueueId)
 493         {
 494             MPDeleteQueue( m_notifyQueueId );
 495             m_notifyQueueId = kInvalidID ;
 496         }
 497     }
 498
 499     // thread function
 500     static OSStatus MacThreadStart(void* arg);
 501
 502     // create a new (suspended) thread (for the given thread object)
 503     bool Create(wxThread *thread, unsigned int stackSize);
 504
 505     // thread actions
 506
 507     // start the thread
 508     wxThreadError Run();
 509
 510     // unblock the thread allowing it to run
 511     void SignalRun() { m_semRun.Post(); }
 512
 513     // ask the thread to terminate
 514     void Wait();
 515
 516     // go to sleep until Resume() is called
 517     void Pause();
 518
 519     // resume the thread
 520     void Resume();
 521
 522     // accessors
 523     // priority
 524     int GetPriority() const
 525     { return m_prio; }
 526     void SetPriority(int prio);
 527
 528     // state
 529     wxThreadState GetState() const
 530     { return m_state; }
 531     void SetState(wxThreadState state)
 532     { m_state = state; }
 533
 534     // Get the ID of this thread's underlying MP Services task.
 535     MPTaskID  GetId() const
 536     { return m_tid; }
 537
 538     void SetCancelFlag()
 539     { m_cancelled = true; }
 540
 541     bool WasCancelled() const
 542     { return m_cancelled; }
 543
 544     // exit code
 545     void SetExitCode(wxThread::ExitCode exitcode)
 546     { m_exitcode = exitcode; }
 547     wxThread::ExitCode GetExitCode() const
 548     { return m_exitcode; }
 549
 550     // the pause flag
 551     void SetReallyPaused(bool paused)
 552     { m_isPaused = paused; }
 553     bool IsReallyPaused() const
 554     { return m_isPaused; }
 555
 556     // tell the thread that it is a detached one
 557     void Detach()
 558     {
 559         wxCriticalSectionLocker lock(m_csJoinFlag);
 560
 561         m_shouldBeJoined = false;
 562         m_isDetached = true;
 563     }
 564
 565 private:
 566     // the thread we're associated with
 567     wxThread *      m_thread;
 568
 569     MPTaskID        m_tid;                // thread id
 570     MPQueueID        m_notifyQueueId;    // its notification queue
 571
 572     wxThreadState m_state;              // see wxThreadState enum
 573     int           m_prio;               // in wxWidgets units: from 0 to 100
 574
 575     // this flag is set when the thread should terminate
 576     bool m_cancelled;
 577
 578     // this flag is set when the thread is blocking on m_semSuspend
 579     bool m_isPaused;
 580
 581     // the thread exit code - only used for joinable (!detached) threads and
 582     // is only valid after the thread termination
 583     wxThread::ExitCode m_exitcode;
 584
 585     // many threads may call Wait(), but only one of them should call
 586     // pthread_join(), so we have to keep track of this
 587     wxCriticalSection m_csJoinFlag;
 588     bool m_shouldBeJoined;
 589     bool m_isDetached;
 590
 591     // this semaphore is posted by Run() and the threads Entry() is not
 592     // called before it is done
 593     wxSemaphore m_semRun;
 594
 595     // this one is signaled when the thread should resume after having been
 596     // Pause()d
 597     wxSemaphore m_semSuspend;
 598 };
 599
 600 OSStatus wxThreadInternal::MacThreadStart(void *parameter)
 601 {
 602     wxThread* thread = (wxThread*) parameter ;
 603     wxThreadInternal *pthread = thread->m_internal;
 604
 605     // add to TLS so that This() will work
 606     verify_noerr( MPSetTaskStorageValue( gs_tlsForWXThread , (TaskStorageValue) thread ) ) ;
 607
 608     // have to declare this before pthread_cleanup_push() which defines a
 609     // block!
 610     bool dontRunAtAll;
 611
 612     // wait for the semaphore to be posted from Run()
 613     pthread->m_semRun.Wait();
 614
 615     // test whether we should run the run at all - may be it was deleted
 616     // before it started to Run()?
 617     {
 618         wxCriticalSectionLocker lock(thread->m_critsect);
 619
 620         dontRunAtAll = pthread->GetState() == STATE_NEW &&
 621                        pthread->WasCancelled();
 622     }
 623
 624     if ( !dontRunAtAll )
 625     {
 626         pthread->m_exitcode = thread->Entry();
 627
 628         {
 629             wxCriticalSectionLocker lock(thread->m_critsect);
 630             pthread->SetState( STATE_EXITED );
 631         }
 632     }
 633
 634     if ( dontRunAtAll )
 635     {
 636         if ( pthread->m_isDetached )
 637             delete thread;
 638
 639         return -1;
 640     }
 641     else
 642     {
 643         // on Mac for the running code,
 644         // the correct thread termination is to return
 645
 646         // terminate the thread
 647         thread->Exit( pthread->m_exitcode );
 648
 649         return (OSStatus) NULL; // pthread->m_exitcode;
 650     }
 651 }
 652
 653 bool wxThreadInternal::Create( wxThread *thread, unsigned int stackSize )
 654 {
 655     wxASSERT_MSG( m_state == STATE_NEW && !m_tid,
 656                     wxT("Create()ing thread twice?") );
 657
 658     if ( thread->IsDetached() )
 659         Detach();
 660
 661     OSStatus err = noErr;
 662     m_thread = thread;
 663
 664     if ( m_notifyQueueId == kInvalidID )
 665     {
 666         OSStatus err = MPCreateQueue( &m_notifyQueueId );
 667         if (err != noErr)
 668         {
 669             wxLogSysError( wxT("Can't create the thread event queue") );
 670
 671             return false;
 672         }
 673     }
 674
 675     m_state = STATE_NEW;
 676
 677     err = MPCreateTask(
 678         MacThreadStart, (void*)m_thread, stackSize,
 679         m_notifyQueueId, &m_exitcode, 0, 0, &m_tid );
 680
 681     if (err != noErr)
 682     {
 683         wxLogSysError( wxT("Can't create thread") );
 684
 685         return false;
 686     }
 687
 688     if ( m_prio != wxPRIORITY_DEFAULT )
 689         SetPriority( m_prio );
 690
 691     return true;
 692 }
 693
 694 void wxThreadInternal::SetPriority( int priority )
 695 {
 696     m_prio = priority;
 697
 698     if (m_tid)
 699     {
 700         // Mac priorities range from 1 to 10,000, with a default of 100.
 701         // wxWidgets priorities range from 0 to 100 with a default of 50.
 702         // We can map wxWidgets to Mac priorities easily by assuming
 703         // the former uses a logarithmic scale.
 704         const unsigned int macPriority = (int)( exp( priority / 25.0 * log( 10.0)) + 0.5);
 705
 706         MPSetTaskWeight( m_tid, macPriority );
 707     }
 708 }
 709
 710 wxThreadError wxThreadInternal::Run()
 711 {
 712     wxCHECK_MSG( GetState() == STATE_NEW, wxTHREAD_RUNNING,
 713                  wxT("thread may only be started once after Create()") );
 714
 715     SetState( STATE_RUNNING );
 716
 717     // wake up threads waiting for our start
 718     SignalRun();
 719
 720     return wxTHREAD_NO_ERROR;
 721 }
 722
 723 void wxThreadInternal::Wait()
 724 {
 725    wxCHECK_RET( !m_isDetached, wxT("can't wait for a detached thread") );
 726
 727     // if the thread we're waiting for is waiting for the GUI mutex, we will
 728     // deadlock so make sure we release it temporarily
 729     if ( wxThread::IsMain() )
 730     {
 731         // give the thread we're waiting for chance to do the GUI call
 732         // it might be in, we don't do this conditionally as the to be waited on
 733         // thread might have to acquire the mutex later but before terminating
 734         if ( wxGuiOwnedByMainThread() )
 735             wxMutexGuiLeave();
 736     }
 737
 738     {
 739         wxCriticalSectionLocker lock(m_csJoinFlag);
 740
 741         if ( m_shouldBeJoined )
 742         {
 743             void *param1, *param2, *rc;
 744
 745             OSStatus err = MPWaitOnQueue(
 746                 m_notifyQueueId,
 747                 &param1,
 748                 &param2,
 749                 &rc,
 750                 kDurationForever );
 751             if (err != noErr)
 752             {
 753                 wxLogSysError( wxT( "Cannot wait for thread termination."));
 754                 rc = (void*) -1;
 755             }
 756
 757             // actually param1 would be the address of m_exitcode
 758             // but we don't need this here
 759             m_exitcode = rc;
 760
 761             m_shouldBeJoined = false;
 762         }
 763     }
 764 }
 765
 766 void wxThreadInternal::Pause()
 767 {
 768     // the state is set from the thread which pauses us first, this function
 769     // is called later so the state should have been already set
 770     wxCHECK_RET( m_state == STATE_PAUSED,
 771                  wxT("thread must first be paused with wxThread::Pause().") );
 772
 773     // wait until the semaphore is Post()ed from Resume()
 774     m_semSuspend.Wait();
 775 }
 776
 777 void wxThreadInternal::Resume()
 778 {
 779     wxCHECK_RET( m_state == STATE_PAUSED,
 780                  wxT("can't resume thread which is not suspended.") );
 781
 782     // the thread might be not actually paused yet - if there were no call to
 783     // TestDestroy() since the last call to Pause() for example
 784     if ( IsReallyPaused() )
 785     {
 786         // wake up Pause()
 787         m_semSuspend.Post();
 788
 789         // reset the flag
 790         SetReallyPaused( false );
 791     }
 792
 793     SetState( STATE_RUNNING );
 794 }
 795
 796 // static functions
 797 // ----------------
 798
 799 wxThread *wxThread::This()
 800 {
 801     wxThread* thr = (wxThread*) MPGetTaskStorageValue( gs_tlsForWXThread ) ;
 802
 803     return thr;
 804 }
 805
 806 #ifdef Yield
 807 #undef Yield
 808 #endif
 809
 810 void wxThread::Yield()
 811 {
 812     CFRunLoopRunInMode( kCFRunLoopDefaultMode , 0 , true ) ;
 813
 814     MPYield();
 815 }
 816
 817 void wxThread::Sleep( unsigned long milliseconds )
 818 {
 819     AbsoluteTime wakeup = AddDurationToAbsolute( milliseconds, UpTime() );
 820     MPDelayUntil( &wakeup );
 821 }
 822
 823 int wxThread::GetCPUCount()
 824 {
 825     return MPProcessors();
 826 }
 827
 828 unsigned long wxThread::GetCurrentId()
 829 {
 830     return (unsigned long)MPCurrentTaskID();
 831 }
 832
 833 bool wxThread::SetConcurrency( size_t WXUNUSED(level) )
 834 {
 835     // Cannot be set in MacOS.
 836     return false;
 837 }
 838
 839 wxThread::wxThread( wxThreadKind kind )
 840 {
 841     g_numberOfThreads++;
 842     m_internal = new wxThreadInternal();
 843
 844     m_isDetached = (kind == wxTHREAD_DETACHED);
 845 }
 846
 847 wxThread::~wxThread()
 848 {
 849     wxASSERT_MSG( g_numberOfThreads>0 , wxT("More threads deleted than created.") ) ;
 850
 851     g_numberOfThreads--;
 852
 853     m_critsect.Enter();
 854
 855     // check that the thread either exited or couldn't be created
 856     if ( m_internal->GetState() != STATE_EXITED &&
 857          m_internal->GetState() != STATE_NEW )
 858     {
 859         wxLogDebug(
 860             wxT("The thread %ld is being destroyed although it is still running! The application may crash."),
 861             GetId() );
 862     }
 863
 864     m_critsect.Leave();
 865
 866     wxDELETE( m_internal ) ;
 867 }
 868
 869 wxThreadError wxThread::Create( unsigned int stackSize )
 870 {
 871     wxCriticalSectionLocker lock(m_critsect);
 872
 873     if ( !m_internal->Create(this, stackSize) )
 874     {
 875         m_internal->SetState( STATE_EXITED );
 876         return wxTHREAD_NO_RESOURCE;
 877     }
 878
 879     return wxTHREAD_NO_ERROR;
 880 }
 881
 882 wxThreadError wxThread::Run()
 883 {
 884     wxCriticalSectionLocker lock(m_critsect);
 885
 886     // Create the thread if it wasn't created yet with an explicit
 887     // Create() call:
 888     if ( m_internal->GetId() == kInvalidID )
 889     {
 890         if ( !m_internal->Create(this, stackSize) )
 891         {
 892             m_internal->SetState( STATE_EXITED );
 893             return wxTHREAD_NO_RESOURCE;
 894         }
 895     }
 896
 897     wxCHECK_MSG( m_internal->GetId(), wxTHREAD_MISC_ERROR,
 898                  wxT("must call wxThread::Create() first") );
 899
 900     return m_internal->Run();
 901 }
 902
 903 // -----------------------------------------------------------------------------
 904 // pause/resume
 905 // -----------------------------------------------------------------------------
 906
 907 wxThreadError wxThread::Pause()
 908 {
 909     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
 910                  wxT("a thread can't pause itself") );
 911
 912     wxCriticalSectionLocker lock(m_critsect);
 913
 914     if ( m_internal->GetState() != STATE_RUNNING )
 915     {
 916         wxLogDebug( wxT("Can't pause thread which is not running.") );
 917
 918         return wxTHREAD_NOT_RUNNING;
 919     }
 920
 921     // just set a flag, the thread will be really paused only during the next
 922     // call to TestDestroy()
 923     m_internal->SetState( STATE_PAUSED );
 924
 925     return wxTHREAD_NO_ERROR;
 926 }
 927
 928 wxThreadError wxThread::Resume()
 929 {
 930     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
 931                  wxT("a thread can't resume itself") );
 932
 933     wxCriticalSectionLocker lock(m_critsect);
 934
 935     wxThreadState state = m_internal->GetState();
 936
 937     switch ( state )
 938     {
 939         case STATE_PAUSED:
 940             m_internal->Resume();
 941             return wxTHREAD_NO_ERROR;
 942
 943         case STATE_EXITED:
 944             return wxTHREAD_NO_ERROR;
 945
 946         default:
 947             wxLogDebug( wxT("Attempt to resume a thread which is not paused.") );
 948
 949             return wxTHREAD_MISC_ERROR;
 950     }
 951 }
 952
 953 // -----------------------------------------------------------------------------
 954 // exiting thread
 955 // -----------------------------------------------------------------------------
 956
 957 wxThread::ExitCode wxThread::Wait(wxThreadWait WXUNUSED(waitMode))
 958 {
 959     wxCHECK_MSG( This() != this, (ExitCode)-1,
 960                  wxT("a thread can't wait for itself") );
 961
 962     wxCHECK_MSG( !m_isDetached, (ExitCode)-1,
 963                  wxT("can't wait for detached thread") );
 964
 965     m_internal->Wait();
 966
 967     return m_internal->GetExitCode();
 968 }
 969
 970 wxThreadError wxThread::Delete(ExitCode *rc, wxThreadWait WXUNUSED(waitMode))
 971 {
 972     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
 973                  wxT("a thread can't delete itself") );
 974
 975     bool isDetached = m_isDetached;
 976
 977     m_critsect.Enter();
 978     wxThreadState state = m_internal->GetState();
 979
 980     // ask the thread to stop
 981     m_internal->SetCancelFlag();
 982
 983     m_critsect.Leave();
 984
 985     switch ( state )
 986     {
 987         case STATE_NEW:
 988             // we need to wake up the thread so that PthreadStart() will
 989             // terminate - right now it's blocking on run semaphore in
 990             // PthreadStart()
 991             m_internal->SignalRun();
 992
 993             // fall through
 994
 995         case STATE_EXITED:
 996             // nothing to do
 997             break;
 998
 999         case STATE_PAUSED:
1000             // resume the thread first
1001             m_internal->Resume();
1002
1003             // fall through
1004
1005         default:
1006             if ( !isDetached )
1007             {
1008                 // wait until the thread stops
1009                 m_internal->Wait();
1010
1011                 if ( rc )
1012                 {
1013                     // return the exit code of the thread
1014                     *rc = m_internal->GetExitCode();
1015                 }
1016             }
1017     }
1018
1019     return wxTHREAD_NO_ERROR;
1020 }
1021
1022 wxThreadError wxThread::Kill()
1023 {
1024     wxCHECK_MSG( This() != this, wxTHREAD_MISC_ERROR,
1025                  wxT("a thread can't kill itself") );
1026
1027     switch ( m_internal->GetState() )
1028     {
1029         case STATE_NEW:
1030         case STATE_EXITED:
1031             return wxTHREAD_NOT_RUNNING;
1032
1033         case STATE_PAUSED:
1034             // resume the thread first
1035             Resume();
1036
1037             // fall through
1038
1039         default:
1040             OSStatus err = MPTerminateTask( m_internal->GetId() , -1 ) ;
1041             if (err != noErr)
1042             {
1043                 wxLogError( wxT("Failed to terminate a thread.") );
1044
1045                 return wxTHREAD_MISC_ERROR;
1046             }
1047
1048             if ( m_isDetached )
1049             {
1050                 delete this ;
1051             }
1052             else
1053             {
1054                 // this should be retrieved by Wait actually
1055                 m_internal->SetExitCode( (void*)-1 );
1056             }
1057
1058             return wxTHREAD_NO_ERROR;
1059     }
1060 }
1061
1062 void wxThread::Exit( ExitCode status )
1063 {
1064     wxASSERT_MSG( This() == this,
1065                   wxT("wxThread::Exit() can only be called in the context of the same thread") );
1066
1067     // don't enter m_critsect before calling OnExit() because the user code
1068     // might deadlock if, for example, it signals a condition in OnExit() (a
1069     // common case) while the main thread calls any of functions entering
1070     // m_critsect on us (almost all of them do)
1071     OnExit();
1072
1073     MPTaskID threadid = m_internal->GetId();
1074
1075     if ( IsDetached() )
1076     {
1077         delete this;
1078     }
1079     else // joinable
1080     {
1081         // update the status of the joinable thread
1082         wxCriticalSectionLocker lock( m_critsect );
1083         m_internal->SetState( STATE_EXITED );
1084     }
1085
1086     MPTerminateTask( threadid, (long)status );
1087 }
1088
1089 // also test whether we were paused
1090 bool wxThread::TestDestroy()
1091 {
1092     wxASSERT_MSG( This() == this,
1093                   wxT("wxThread::TestDestroy() can only be called in the context of the same thread") );
1094
1095     m_critsect.Enter();
1096
1097     if ( m_internal->GetState() == STATE_PAUSED )
1098     {
1099         m_internal->SetReallyPaused( true );
1100
1101         // leave the crit section or the other threads will stop too if they attempt
1102         // to call any of (seemingly harmless) IsXXX() functions while we sleep
1103         m_critsect.Leave();
1104
1105         m_internal->Pause();
1106     }
1107     else
1108     {
1109         // thread wasn't requested to pause, nothing to do
1110         m_critsect.Leave();
1111     }
1112
1113     return m_internal->WasCancelled();
1114 }
1115
1116 // -----------------------------------------------------------------------------
1117 // priority setting
1118 // -----------------------------------------------------------------------------
1119
1120 void wxThread::SetPriority(unsigned int prio)
1121 {
1122     wxCHECK_RET( wxPRIORITY_MIN <= prio && prio <= wxPRIORITY_MAX,
1123                  wxT("invalid thread priority") );
1124
1125     wxCriticalSectionLocker lock(m_critsect);
1126
1127     switch ( m_internal->GetState() )
1128     {
1129         case STATE_RUNNING:
1130         case STATE_PAUSED:
1131         case STATE_NEW:
1132             // thread not yet started, priority will be set when it is
1133             m_internal->SetPriority( prio );
1134             break;
1135
1136         case STATE_EXITED:
1137         default:
1138             wxFAIL_MSG( wxT("impossible to set thread priority in this state") );
1139     }
1140 }
1141
1142 unsigned int wxThread::GetPriority() const
1143 {
1144     wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
1145
1146     return m_internal->GetPriority();
1147 }
1148
1149 unsigned long wxThread::GetId() const
1150 {
1151     wxCriticalSectionLocker lock(const_cast<wxCriticalSection &>(m_critsect));
1152
1153     return (unsigned long)m_internal->GetId();
1154 }
1155
1156 // -----------------------------------------------------------------------------
1157 // state tests
1158 // -----------------------------------------------------------------------------
1159
1160 bool wxThread::IsRunning() const
1161 {
1162     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
1163
1164     return m_internal->GetState() == STATE_RUNNING;
1165 }
1166
1167 bool wxThread::IsAlive() const
1168 {
1169     wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
1170
1171     switch ( m_internal->GetState() )
1172     {
1173         case STATE_RUNNING:
1174         case STATE_PAUSED:
1175             return true;
1176
1177         default:
1178             return false;
1179     }
1180 }
1181
1182 bool wxThread::IsPaused() const
1183 {
1184     wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
1185
1186     return (m_internal->GetState() == STATE_PAUSED);
1187 }
1188
1189 // ----------------------------------------------------------------------------
1190 // Automatic initialization for thread module
1191 // ----------------------------------------------------------------------------
1192
1193 class wxThreadModule : public wxModule
1194 {
1195 public:
1196     virtual bool OnInit();
1197     virtual void OnExit();
1198
1199 private:
1200     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1201 };
1202
1203 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1204
1205 bool wxThreadModule::OnInit()
1206 {
1207     bool hasThreadManager =
1208 #ifdef __LP64__
1209         true ; // TODO VERIFY IN NEXT BUILD
1210 #else
1211         MPLibraryIsLoaded();
1212 #endif
1213
1214     if ( !hasThreadManager )
1215     {
1216         wxLogError( wxT("MP thread support is not available on this system" ) ) ;
1217
1218         return false;
1219     }
1220
1221     // main thread's This() is NULL
1222     verify_noerr( MPAllocateTaskStorageIndex( &gs_tlsForWXThread ) ) ;
1223     verify_noerr( MPSetTaskStorageValue( gs_tlsForWXThread, 0 ) ) ;
1224
1225     wxThread::ms_idMainThread = wxThread::GetCurrentId();
1226     gs_critsectWaitingForGui = new wxCriticalSection();
1227
1228     gs_critsectGui = new wxCriticalSection();
1229     gs_critsectGui->Enter();
1230
1231     return true;
1232 }
1233
1234 void wxThreadModule::OnExit()
1235 {
1236     if ( gs_critsectGui )
1237     {
1238         if ( !wxGuiOwnedByMainThread() )
1239         {
1240             gs_critsectGui->Enter();
1241             gs_bGuiOwnedByMainThread = true;
1242         }
1243
1244         gs_critsectGui->Leave();
1245         wxDELETE(gs_critsectGui);
1246     }
1247
1248     wxDELETE(gs_critsectWaitingForGui);
1249 }
1250
1251 // ----------------------------------------------------------------------------
1252 // GUI Serialization copied from MSW implementation
1253 // ----------------------------------------------------------------------------
1254
1255 void wxMutexGuiEnterImpl()
1256 {
1257     // this would dead lock everything...
1258     wxASSERT_MSG( !wxThread::IsMain(),
1259                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1260
1261     // the order in which we enter the critical sections here is crucial!!
1262
1263     // set the flag telling to the main thread that we want to do some GUI
1264     {
1265         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1266
1267         gs_nWaitingForGui++;
1268     }
1269
1270     wxWakeUpMainThread();
1271
1272     // now we may block here because the main thread will soon let us in
1273     // (during the next iteration of OnIdle())
1274     gs_critsectGui->Enter();
1275 }
1276
1277 void wxMutexGuiLeaveImpl()
1278 {
1279     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1280
1281     if ( wxThread::IsMain() )
1282     {
1283         gs_bGuiOwnedByMainThread = false;
1284     }
1285     else
1286     {
1287         // decrement the number of threads waiting for GUI access now
1288         wxASSERT_MSG( gs_nWaitingForGui > 0,
1289                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1290
1291         gs_nWaitingForGui--;
1292
1293         wxWakeUpMainThread();
1294     }
1295
1296     gs_critsectGui->Leave();
1297 }
1298
1299 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1300 {
1301     wxASSERT_MSG( wxThread::IsMain(),
1302                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1303
1304     if ( !gs_critsectWaitingForGui )
1305         return;
1306
1307     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1308
1309     if ( gs_nWaitingForGui == 0 )
1310     {
1311         // no threads are waiting for GUI - so we may acquire the lock without
1312         // any danger (but only if we don't already have it)
1313         if ( !wxGuiOwnedByMainThread() )
1314         {
1315             gs_critsectGui->Enter();
1316
1317             gs_bGuiOwnedByMainThread = true;
1318         }
1319         //else: already have it, nothing to do
1320     }
1321     else
1322     {
1323         // some threads are waiting, release the GUI lock if we have it
1324         if ( wxGuiOwnedByMainThread() )
1325             wxMutexGuiLeave();
1326         //else: some other worker thread is doing GUI
1327     }
1328 }
1329
1330 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1331 {
1332     return gs_bGuiOwnedByMainThread;
1333 }
1334
1335 // wake up the main thread
1336 void WXDLLEXPORT wxWakeUpMainThread()
1337 {
1338     wxMacWakeUp();
1339 }
1340
1341 // ----------------------------------------------------------------------------
1342 // include common implementation code
1343 // ----------------------------------------------------------------------------
1344
1345 #include "wx/thrimpl.cpp"
1346
1347 #endif // wxUSE_THREADS