src/msw/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        thread.cpp
   3 // Purpose:     wxThread Implementation
   4 // Author:      Original from Wolfram Gloger/Guilhem Lavaux
   5 // Modified by: Vadim Zeitlin to make it work :-)
   6 // Created:     04/22/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
   9 //                  Vadim Zeitlin (1999)
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifdef __GNUG__
  14     #pragma implementation "thread.h"
  15 #endif
  16
  17 // ----------------------------------------------------------------------------
  18 // headers
  19 // ----------------------------------------------------------------------------
  20
  21 // For compilers that support precompilation, includes "wx.h".
  22 #include "wx/wxprec.h"
  23
  24 #if defined(__BORLANDC__)
  25     #pragma hdrstop
  26 #endif
  27
  28 #ifndef WX_PRECOMP
  29 #    include "wx/wx.h"
  30 #endif
  31
  32 #if wxUSE_THREADS
  33
  34 #include "wx/msw/private.h"
  35
  36 #include "wx/module.h"
  37 #include "wx/thread.h"
  38
  39 #ifdef Yield
  40 #    undef Yield
  41 #endif
  42
  43 // must have this symbol defined to get _beginthread/_endthread declarations
  44 #ifndef _MT
  45     #define _MT
  46 #endif
  47
  48 #if defined(__BORLANDC__)
  49     #if !defined(__MT__)
  50         // I can't set -tWM in the IDE (anyone?) so have to do this
  51         #define __MT__
  52     #endif
  53
  54     #if !defined(__MFC_COMPAT__)
  55         // Needed to know about _beginthreadex etc..
  56         #define __MFC_COMPAT__
  57     #endif
  58 #endif // BC++
  59
  60 // define wxUSE_BEGIN_THREAD if the compiler has _beginthreadex() function
  61 // which should be used instead of Win32 ::CreateThread() if possible
  62 #if defined(__VISUALC__) || \
  63     (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \
  64     (defined(__GNUG__) && defined(__MSVCRT__)) || \
  65     defined(__WATCOMC__) || defined(__MWERKS__)
  66
  67     #undef wxUSE_BEGIN_THREAD
  68     #define wxUSE_BEGIN_THREAD
  69 #endif
  70
  71 #ifdef wxUSE_BEGIN_THREAD
  72     // this is where _beginthreadex() is declared
  73     #include <process.h>
  74
  75     // the return type of the thread function entry point
  76     typedef unsigned THREAD_RETVAL;
  77
  78     // the calling convention of the thread function entry point
  79     #define THREAD_CALLCONV __stdcall
  80 #else
  81     // the settings for CreateThread()
  82     typedef DWORD THREAD_RETVAL;
  83     #define THREAD_CALLCONV WINAPI
  84 #endif
  85
  86 // ----------------------------------------------------------------------------
  87 // constants
  88 // ----------------------------------------------------------------------------
  89
  90 // the possible states of the thread ("=>" shows all possible transitions from
  91 // this state)
  92 enum wxThreadState
  93 {
  94     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  95     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  96     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
  97     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
  98     STATE_EXITED        // thread is terminating
  99 };
 100
 101 // ----------------------------------------------------------------------------
 102 // this module globals
 103 // ----------------------------------------------------------------------------
 104
 105 // TLS index of the slot where we store the pointer to the current thread
 106 static DWORD gs_tlsThisThread = 0xFFFFFFFF;
 107
 108 // id of the main thread - the one which can call GUI functions without first
 109 // calling wxMutexGuiEnter()
 110 static DWORD gs_idMainThread = 0;
 111
 112 // if it's FALSE, some secondary thread is holding the GUI lock
 113 static bool gs_bGuiOwnedByMainThread = TRUE;
 114
 115 // critical section which controls access to all GUI functions: any secondary
 116 // thread (i.e. except the main one) must enter this crit section before doing
 117 // any GUI calls
 118 static wxCriticalSection *gs_critsectGui = NULL;
 119
 120 // critical section which protects gs_nWaitingForGui variable
 121 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
 122
 123 // number of threads waiting for GUI in wxMutexGuiEnter()
 124 static size_t gs_nWaitingForGui = 0;
 125
 126 // are we waiting for a thread termination?
 127 static bool gs_waitingForThread = FALSE;
 128
 129 // ============================================================================
 130 // Windows implementation of thread classes
 131 // ============================================================================
 132
 133 // ----------------------------------------------------------------------------
 134 // wxMutex implementation
 135 // ----------------------------------------------------------------------------
 136
 137 class wxMutexInternal
 138 {
 139 public:
 140     wxMutexInternal()
 141     {
 142         m_mutex = ::CreateMutex(NULL, FALSE, NULL);
 143         if ( !m_mutex )
 144         {
 145             wxLogSysError(_("Can not create mutex"));
 146         }
 147     }
 148
 149     ~wxMutexInternal() { if ( m_mutex ) ::CloseHandle(m_mutex); }
 150
 151 public:
 152     HANDLE m_mutex;
 153 };
 154
 155 wxMutex::wxMutex()
 156 {
 157     m_internal = new wxMutexInternal;
 158
 159     m_locked = 0;
 160 }
 161
 162 wxMutex::~wxMutex()
 163 {
 164     if ( m_locked > 0 )
 165     {
 166         wxLogDebug(_T("Warning: freeing a locked mutex (%d locks)."), m_locked);
 167     }
 168
 169     delete m_internal;
 170 }
 171
 172 wxMutexError wxMutex::Lock()
 173 {
 174     DWORD ret;
 175
 176     ret = WaitForSingleObject(m_internal->m_mutex, INFINITE);
 177     switch ( ret )
 178     {
 179         case WAIT_ABANDONED:
 180             return wxMUTEX_BUSY;
 181
 182         case WAIT_OBJECT_0:
 183             // ok
 184             break;
 185
 186         case WAIT_FAILED:
 187             wxLogSysError(_("Couldn't acquire a mutex lock"));
 188             return wxMUTEX_MISC_ERROR;
 189
 190         case WAIT_TIMEOUT:
 191         default:
 192             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 193     }
 194
 195     m_locked++;
 196     return wxMUTEX_NO_ERROR;
 197 }
 198
 199 wxMutexError wxMutex::TryLock()
 200 {
 201     DWORD ret;
 202
 203     ret = WaitForSingleObject(m_internal->m_mutex, 0);
 204     if (ret == WAIT_TIMEOUT || ret == WAIT_ABANDONED)
 205         return wxMUTEX_BUSY;
 206
 207     m_locked++;
 208     return wxMUTEX_NO_ERROR;
 209 }
 210
 211 wxMutexError wxMutex::Unlock()
 212 {
 213     if (m_locked > 0)
 214         m_locked--;
 215
 216     BOOL ret = ReleaseMutex(m_internal->m_mutex);
 217     if ( ret == 0 )
 218     {
 219         wxLogSysError(_("Couldn't release a mutex"));
 220         return wxMUTEX_MISC_ERROR;
 221     }
 222
 223     return wxMUTEX_NO_ERROR;
 224 }
 225
 226 // ==========================================================================
 227 // wxSemaphore
 228 // ==========================================================================
 229
 230 // --------------------------------------------------------------------------
 231 // wxSemaphoreInternal
 232 // --------------------------------------------------------------------------
 233
 234 class wxSemaphoreInternal
 235 {
 236 public:
 237     wxSemaphoreInternal( int initialcount = 0, int maxcount = 0 );
 238     ~wxSemaphoreInternal();
 239
 240     void Wait();
 241     bool TryWait();
 242
 243     bool Wait( unsigned long timeout_millis );
 244
 245     void Post();
 246
 247 private:
 248     HANDLE m_semaphore;
 249 };
 250
 251 wxSemaphoreInternal::wxSemaphoreInternal( int initialcount, int maxcount )
 252 {
 253     if ( maxcount == 0 )
 254     {
 255         // make it practically infinite
 256         maxcount = INT_MAX;
 257     }
 258
 259     m_semaphore = ::CreateSemaphore( NULL, initialcount, maxcount, NULL );
 260     if ( !m_semaphore )
 261     {
 262         wxLogLastError(_T("CreateSemaphore()"));
 263     }
 264 }
 265
 266 wxSemaphoreInternal::~wxSemaphoreInternal()
 267 {
 268     CloseHandle( m_semaphore );
 269 }
 270
 271 void wxSemaphoreInternal::Wait()
 272 {
 273     if ( ::WaitForSingleObject( m_semaphore, INFINITE ) != WAIT_OBJECT_0 )
 274     {
 275         wxLogLastError(_T("WaitForSingleObject"));
 276     }
 277 }
 278
 279 bool wxSemaphoreInternal::TryWait()
 280 {
 281     return Wait(0);
 282 }
 283
 284 bool wxSemaphoreInternal::Wait( unsigned long timeout_millis )
 285 {
 286     DWORD result = ::WaitForSingleObject( m_semaphore, timeout_millis );
 287
 288     switch ( result )
 289     {
 290         case WAIT_OBJECT_0:
 291            return TRUE;
 292
 293         case WAIT_TIMEOUT:
 294            break;
 295
 296         default:
 297             wxLogLastError(_T("WaitForSingleObject()"));
 298     }
 299
 300     return FALSE;
 301 }
 302
 303 void wxSemaphoreInternal::Post()
 304 {
 305     if ( !::ReleaseSemaphore( m_semaphore, 1, NULL ) )
 306     {
 307         wxLogLastError(_T("ReleaseSemaphore"));
 308     }
 309 }
 310
 311 // --------------------------------------------------------------------------
 312 // wxSemaphore
 313 // --------------------------------------------------------------------------
 314
 315 wxSemaphore::wxSemaphore( int initialcount, int maxcount )
 316 {
 317     m_internal = new wxSemaphoreInternal( initialcount, maxcount );
 318 }
 319
 320 wxSemaphore::~wxSemaphore()
 321 {
 322     delete m_internal;
 323 }
 324
 325 void wxSemaphore::Wait()
 326 {
 327     m_internal->Wait();
 328 }
 329
 330 bool wxSemaphore::TryWait()
 331 {
 332     return m_internal->TryWait();
 333 }
 334
 335 bool wxSemaphore::Wait( unsigned long timeout_millis )
 336 {
 337     return m_internal->Wait( timeout_millis );
 338 }
 339
 340 void wxSemaphore::Post()
 341 {
 342     m_internal->Post();
 343 }
 344
 345
 346 // ==========================================================================
 347 // wxCondition
 348 // ==========================================================================
 349
 350 // --------------------------------------------------------------------------
 351 // wxConditionInternal
 352 // --------------------------------------------------------------------------
 353
 354 class wxConditionInternal
 355 {
 356 public:
 357     wxConditionInternal(wxMutex& mutex);
 358
 359     void Wait();
 360
 361     bool Wait( unsigned long timeout_millis );
 362
 363     void Signal();
 364
 365     void Broadcast();
 366
 367 private:
 368     int m_numWaiters;
 369     wxMutex m_mutexNumWaiters;
 370
 371     wxMutex& m_mutex;
 372
 373     wxSemaphore m_semaphore;
 374
 375     DECLARE_NO_COPY_CLASS(wxConditionInternal)
 376 };
 377
 378 wxConditionInternal::wxConditionInternal(wxMutex& mutex)
 379                    : m_mutex(mutex)
 380 {
 381
 382     m_numWaiters = 0;
 383 }
 384
 385 void wxConditionInternal::Wait()
 386 {
 387     // increment the number of waiters
 388     m_mutexNumWaiters.Lock();
 389     m_numWaiters++;
 390     m_mutexNumWaiters.Unlock();
 391
 392     m_mutex.Unlock();
 393
 394     // a potential race condition can occur here
 395     //
 396     // after a thread increments nwaiters, and unlocks the mutex and before the
 397     // semaphore.Wait() is called, if another thread can cause a signal to be
 398     // generated
 399     //
 400     // this race condition is handled by using a semaphore and incrementing the
 401     // semaphore only if 'nwaiters' is greater that zero since the semaphore,
 402     // can 'remember' signals the race condition will not occur
 403
 404     // wait ( if necessary ) and decrement semaphore
 405     m_semaphore.Wait();
 406
 407     m_mutex.Lock();
 408 }
 409
 410 bool wxConditionInternal::Wait( unsigned long timeout_millis )
 411 {
 412     m_mutexNumWaiters.Lock();
 413     m_numWaiters++;
 414     m_mutexNumWaiters.Unlock();
 415
 416     m_mutex.Unlock();
 417
 418     // a race condition can occur at this point in the code
 419     //
 420     // please see the comments in Wait(), for details
 421
 422     bool success = TRUE;
 423
 424     bool result = m_semaphore.Wait( timeout_millis );
 425
 426     if ( !result )
 427     {
 428         // another potential race condition exists here it is caused when a
 429         // 'waiting' thread timesout, and returns from WaitForSingleObject, but
 430         // has not yet decremented 'nwaiters'.
 431         //
 432         // at this point if another thread calls signal() then the semaphore
 433         // will be incremented, but the waiting thread will miss it.
 434         //
 435         // to handle this particular case, the waiting thread calls
 436         // WaitForSingleObject again with a timeout of 0, after locking
 437         // 'nwaiters_mutex'. this call does not block because of the zero
 438         // timeout, but will allow the waiting thread to catch the missed
 439         // signals.
 440         m_mutexNumWaiters.Lock();
 441         result = m_semaphore.Wait( 0 );
 442
 443         if ( !result )
 444         {
 445             m_numWaiters--;
 446             success = FALSE;
 447         }
 448
 449         m_mutexNumWaiters.Unlock();
 450     }
 451
 452     m_mutex.Lock();
 453
 454     return success;
 455 }
 456
 457 void wxConditionInternal::Signal()
 458 {
 459     m_mutexNumWaiters.Lock();
 460
 461     if ( m_numWaiters > 0 )
 462     {
 463         // increment the semaphore by 1
 464         m_semaphore.Post();
 465
 466         m_numWaiters--;
 467     }
 468
 469     m_mutexNumWaiters.Unlock();
 470 }
 471
 472 void wxConditionInternal::Broadcast()
 473 {
 474     m_mutexNumWaiters.Lock();
 475
 476     while ( m_numWaiters > 0 )
 477     {
 478         m_semaphore.Post();
 479         m_numWaiters--;
 480     }
 481
 482     m_mutexNumWaiters.Unlock();
 483 }
 484
 485 // ----------------------------------------------------------------------------
 486 // wxCondition implementation
 487 // ----------------------------------------------------------------------------
 488
 489 wxCondition::wxCondition(wxMutex& mutex)
 490 {
 491     m_internal = new wxConditionInternal( mutex );
 492 }
 493
 494 wxCondition::~wxCondition()
 495 {
 496     delete m_internal;
 497 }
 498
 499 void wxCondition::Wait()
 500 {
 501     m_internal->Wait();
 502 }
 503
 504 bool wxCondition::Wait( unsigned long timeout_millis )
 505 {
 506     return m_internal->Wait(timeout_millis);
 507 }
 508
 509 void wxCondition::Signal()
 510 {
 511     m_internal->Signal();
 512 }
 513
 514 void wxCondition::Broadcast()
 515 {
 516     m_internal->Broadcast();
 517 }
 518
 519 // ----------------------------------------------------------------------------
 520 // wxCriticalSection implementation
 521 // ----------------------------------------------------------------------------
 522
 523 wxCriticalSection::wxCriticalSection()
 524 {
 525 #ifdef __WXDEBUG__
 526     // Done this way to stop warnings during compilation about statement
 527     // always being FALSE
 528     int csSize = sizeof(CRITICAL_SECTION);
 529     int bSize  = sizeof(m_buffer);
 530     wxASSERT_MSG( csSize <= bSize,
 531                   _T("must increase buffer size in wx/thread.h") );
 532 #endif
 533
 534     ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
 535 }
 536
 537 wxCriticalSection::~wxCriticalSection()
 538 {
 539     ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
 540 }
 541
 542 void wxCriticalSection::Enter()
 543 {
 544     ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
 545 }
 546
 547 void wxCriticalSection::Leave()
 548 {
 549     ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
 550 }
 551
 552 // ----------------------------------------------------------------------------
 553 // wxThread implementation
 554 // ----------------------------------------------------------------------------
 555
 556 // wxThreadInternal class
 557 // ----------------------
 558
 559 class wxThreadInternal
 560 {
 561 public:
 562     wxThreadInternal()
 563     {
 564         m_hThread = 0;
 565         m_state = STATE_NEW;
 566         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 567     }
 568
 569     ~wxThreadInternal()
 570     {
 571         Free();
 572     }
 573
 574     void Free()
 575     {
 576         if ( m_hThread )
 577         {
 578             if ( !::CloseHandle(m_hThread) )
 579             {
 580                 wxLogLastError(wxT("CloseHandle(thread)"));
 581             }
 582
 583             m_hThread = 0;
 584         }
 585     }
 586
 587     // create a new (suspended) thread (for the given thread object)
 588     bool Create(wxThread *thread, unsigned int stackSize);
 589
 590     // suspend/resume/terminate
 591     bool Suspend();
 592     bool Resume();
 593     void Cancel() { m_state = STATE_CANCELED; }
 594
 595     // thread state
 596     void SetState(wxThreadState state) { m_state = state; }
 597     wxThreadState GetState() const { return m_state; }
 598
 599     // thread priority
 600     void SetPriority(unsigned int priority);
 601     unsigned int GetPriority() const { return m_priority; }
 602
 603     // thread handle and id
 604     HANDLE GetHandle() const { return m_hThread; }
 605     DWORD  GetId() const { return m_tid; }
 606
 607     // thread function
 608     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 609
 610 private:
 611     HANDLE        m_hThread;    // handle of the thread
 612     wxThreadState m_state;      // state, see wxThreadState enum
 613     unsigned int  m_priority;   // thread priority in "wx" units
 614     DWORD         m_tid;        // thread id
 615 };
 616
 617 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 618 {
 619     THREAD_RETVAL rc;
 620     bool wasCancelled;
 621
 622     // first of all, check whether we hadn't been cancelled already and don't
 623     // start the user code at all then
 624     wxThread *thread = (wxThread *)param;
 625     if ( thread->m_internal->GetState() == STATE_EXITED )
 626     {
 627         rc = (THREAD_RETVAL)-1;
 628         wasCancelled = TRUE;
 629     }
 630     else // do run thread
 631     {
 632         // store the thread object in the TLS
 633         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 634         {
 635             wxLogSysError(_("Can not start thread: error writing TLS."));
 636
 637             return (DWORD)-1;
 638         }
 639
 640         rc = (THREAD_RETVAL)thread->Entry();
 641
 642         // enter m_critsect before changing the thread state
 643         thread->m_critsect.Enter();
 644         wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
 645         thread->m_internal->SetState(STATE_EXITED);
 646         thread->m_critsect.Leave();
 647     }
 648
 649     thread->OnExit();
 650
 651     // if the thread was cancelled (from Delete()), then its handle is still
 652     // needed there
 653     if ( thread->IsDetached() && !wasCancelled )
 654     {
 655         // auto delete
 656         delete thread;
 657     }
 658     //else: the joinable threads handle will be closed when Wait() is done
 659
 660     return rc;
 661 }
 662
 663 void wxThreadInternal::SetPriority(unsigned int priority)
 664 {
 665     m_priority = priority;
 666
 667     // translate wxWindows priority to the Windows one
 668     int win_priority;
 669     if (m_priority <= 20)
 670         win_priority = THREAD_PRIORITY_LOWEST;
 671     else if (m_priority <= 40)
 672         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 673     else if (m_priority <= 60)
 674         win_priority = THREAD_PRIORITY_NORMAL;
 675     else if (m_priority <= 80)
 676         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 677     else if (m_priority <= 100)
 678         win_priority = THREAD_PRIORITY_HIGHEST;
 679     else
 680     {
 681         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 682         win_priority = THREAD_PRIORITY_NORMAL;
 683     }
 684
 685     if ( !::SetThreadPriority(m_hThread, win_priority) )
 686     {
 687         wxLogSysError(_("Can't set thread priority"));
 688     }
 689 }
 690
 691 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 692 {
 693     // for compilers which have it, we should use C RTL function for thread
 694     // creation instead of Win32 API one because otherwise we will have memory
 695     // leaks if the thread uses C RTL (and most threads do)
 696 #ifdef wxUSE_BEGIN_THREAD
 697
 698     // Watcom is reported to not like 0 stack size (which means "use default"
 699     // for the other compilers and is also the default value for stackSize)
 700 #ifdef __WATCOMC__
 701     if ( !stackSize )
 702         stackSize = 10240;
 703 #endif // __WATCOMC__
 704
 705     m_hThread = (HANDLE)_beginthreadex
 706                         (
 707                           NULL,                             // default security
 708                           stackSize,
 709                           wxThreadInternal::WinThreadStart, // entry point
 710                           thread,
 711                           CREATE_SUSPENDED,
 712                           (unsigned int *)&m_tid
 713                         );
 714 #else // compiler doesn't have _beginthreadex
 715     m_hThread = ::CreateThread
 716                   (
 717                     NULL,                               // default security
 718                     stackSize,                          // stack size
 719                     wxThreadInternal::WinThreadStart,   // thread entry point
 720                     (LPVOID)thread,                     // parameter
 721                     CREATE_SUSPENDED,                   // flags
 722                     &m_tid                              // [out] thread id
 723                   );
 724 #endif // _beginthreadex/CreateThread
 725
 726     if ( m_hThread == NULL )
 727     {
 728         wxLogSysError(_("Can't create thread"));
 729
 730         return FALSE;
 731     }
 732
 733     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 734     {
 735         SetPriority(m_priority);
 736     }
 737
 738     return TRUE;
 739 }
 740
 741 bool wxThreadInternal::Suspend()
 742 {
 743     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 744     if ( nSuspendCount == (DWORD)-1 )
 745     {
 746         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 747
 748         return FALSE;
 749     }
 750
 751     m_state = STATE_PAUSED;
 752
 753     return TRUE;
 754 }
 755
 756 bool wxThreadInternal::Resume()
 757 {
 758     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 759     if ( nSuspendCount == (DWORD)-1 )
 760     {
 761         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 762
 763         return FALSE;
 764     }
 765
 766     // don't change the state from STATE_EXITED because it's special and means
 767     // we are going to terminate without running any user code - if we did it,
 768     // the codei n Delete() wouldn't work
 769     if ( m_state != STATE_EXITED )
 770     {
 771         m_state = STATE_RUNNING;
 772     }
 773
 774     return TRUE;
 775 }
 776
 777 // static functions
 778 // ----------------
 779
 780 wxThread *wxThread::This()
 781 {
 782     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 783
 784     // be careful, 0 may be a valid return value as well
 785     if ( !thread && (::GetLastError() != NO_ERROR) )
 786     {
 787         wxLogSysError(_("Couldn't get the current thread pointer"));
 788
 789         // return NULL...
 790     }
 791
 792     return thread;
 793 }
 794
 795 bool wxThread::IsMain()
 796 {
 797     return ::GetCurrentThreadId() == gs_idMainThread;
 798 }
 799
 800 #ifdef Yield
 801 #undef Yield
 802 #endif
 803
 804 void wxThread::Yield()
 805 {
 806     // 0 argument to Sleep() is special and means to just give away the rest of
 807     // our timeslice
 808     ::Sleep(0);
 809 }
 810
 811 void wxThread::Sleep(unsigned long milliseconds)
 812 {
 813     ::Sleep(milliseconds);
 814 }
 815
 816 int wxThread::GetCPUCount()
 817 {
 818     SYSTEM_INFO si;
 819     GetSystemInfo(&si);
 820
 821     return si.dwNumberOfProcessors;
 822 }
 823
 824 unsigned long wxThread::GetCurrentId()
 825 {
 826     return (unsigned long)::GetCurrentThreadId();
 827 }
 828
 829 bool wxThread::SetConcurrency(size_t level)
 830 {
 831     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 832
 833     // ok only for the default one
 834     if ( level == 0 )
 835         return 0;
 836
 837     // get system affinity mask first
 838     HANDLE hProcess = ::GetCurrentProcess();
 839     DWORD dwProcMask, dwSysMask;
 840     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 841     {
 842         wxLogLastError(_T("GetProcessAffinityMask"));
 843
 844         return FALSE;
 845     }
 846
 847     // how many CPUs have we got?
 848     if ( dwSysMask == 1 )
 849     {
 850         // don't bother with all this complicated stuff - on a single
 851         // processor system it doesn't make much sense anyhow
 852         return level == 1;
 853     }
 854
 855     // calculate the process mask: it's a bit vector with one bit per
 856     // processor; we want to schedule the process to run on first level
 857     // CPUs
 858     DWORD bit = 1;
 859     while ( bit )
 860     {
 861         if ( dwSysMask & bit )
 862         {
 863             // ok, we can set this bit
 864             dwProcMask |= bit;
 865
 866             // another process added
 867             if ( !--level )
 868             {
 869                 // and that's enough
 870                 break;
 871             }
 872         }
 873
 874         // next bit
 875         bit <<= 1;
 876     }
 877
 878     // could we set all bits?
 879     if ( level != 0 )
 880     {
 881         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 882
 883         return FALSE;
 884     }
 885
 886     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 887     // exist in Win9x, use RT binding instead
 888
 889     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
 890
 891     // can use static var because we're always in the main thread here
 892     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
 893
 894     if ( !pfnSetProcessAffinityMask )
 895     {
 896         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
 897         if ( hModKernel )
 898         {
 899             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
 900                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
 901         }
 902
 903         // we've discovered a MT version of Win9x!
 904         wxASSERT_MSG( pfnSetProcessAffinityMask,
 905                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
 906     }
 907
 908     if ( !pfnSetProcessAffinityMask )
 909     {
 910         // msg given above - do it only once
 911         return FALSE;
 912     }
 913
 914     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
 915     {
 916         wxLogLastError(_T("SetProcessAffinityMask"));
 917
 918         return FALSE;
 919     }
 920
 921     return TRUE;
 922 }
 923
 924 // ctor and dtor
 925 // -------------
 926
 927 wxThread::wxThread(wxThreadKind kind)
 928 {
 929     m_internal = new wxThreadInternal();
 930
 931     m_isDetached = kind == wxTHREAD_DETACHED;
 932 }
 933
 934 wxThread::~wxThread()
 935 {
 936     delete m_internal;
 937 }
 938
 939 // create/start thread
 940 // -------------------
 941
 942 wxThreadError wxThread::Create(unsigned int stackSize)
 943 {
 944     wxCriticalSectionLocker lock(m_critsect);
 945
 946     if ( !m_internal->Create(this, stackSize) )
 947         return wxTHREAD_NO_RESOURCE;
 948
 949     return wxTHREAD_NO_ERROR;
 950 }
 951
 952 wxThreadError wxThread::Run()
 953 {
 954     wxCriticalSectionLocker lock(m_critsect);
 955
 956     if ( m_internal->GetState() != STATE_NEW )
 957     {
 958         // actually, it may be almost any state at all, not only STATE_RUNNING
 959         return wxTHREAD_RUNNING;
 960     }
 961
 962     // the thread has just been created and is still suspended - let it run
 963     return Resume();
 964 }
 965
 966 // suspend/resume thread
 967 // ---------------------
 968
 969 wxThreadError wxThread::Pause()
 970 {
 971     wxCriticalSectionLocker lock(m_critsect);
 972
 973     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 974 }
 975
 976 wxThreadError wxThread::Resume()
 977 {
 978     wxCriticalSectionLocker lock(m_critsect);
 979
 980     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 981 }
 982
 983 // stopping thread
 984 // ---------------
 985
 986 wxThread::ExitCode wxThread::Wait()
 987 {
 988     // although under Windows we can wait for any thread, it's an error to
 989     // wait for a detached one in wxWin API
 990     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
 991                  _T("can't wait for detached thread") );
 992
 993     ExitCode rc = (ExitCode)-1;
 994
 995     (void)Delete(&rc);
 996
 997     m_internal->Free();
 998
 999     return rc;
1000 }
1001
1002 wxThreadError wxThread::Delete(ExitCode *pRc)
1003 {
1004     ExitCode rc = 0;
1005
1006     // Delete() is always safe to call, so consider all possible states
1007
1008     // we might need to resume the thread, but we might also not need to cancel
1009     // it if it doesn't run yet
1010     bool shouldResume = FALSE,
1011          shouldCancel = TRUE,
1012          isRunning = FALSE;
1013
1014     // check if the thread already started to run
1015     {
1016         wxCriticalSectionLocker lock(m_critsect);
1017
1018         if ( m_internal->GetState() == STATE_NEW )
1019         {
1020             // WinThreadStart() will see it and terminate immediately, no need
1021             // to cancel the thread - but we still need to resume it to let it
1022             // run
1023             m_internal->SetState(STATE_EXITED);
1024
1025             Resume();   // it knows about STATE_EXITED special case
1026
1027             shouldCancel = FALSE;
1028             isRunning = TRUE;
1029
1030             // shouldResume is correctly set to FALSE here
1031         }
1032         else
1033         {
1034             shouldResume = IsPaused();
1035         }
1036     }
1037
1038     // resume the thread if it is paused
1039     if ( shouldResume )
1040         Resume();
1041
1042     HANDLE hThread = m_internal->GetHandle();
1043
1044     // does is still run?
1045     if ( isRunning || IsRunning() )
1046     {
1047         if ( IsMain() )
1048         {
1049             // set flag for wxIsWaitingForThread()
1050             gs_waitingForThread = TRUE;
1051
1052 #if wxUSE_GUI
1053             wxBeginBusyCursor();
1054 #endif // wxUSE_GUI
1055         }
1056
1057         // ask the thread to terminate
1058         if ( shouldCancel )
1059         {
1060             wxCriticalSectionLocker lock(m_critsect);
1061
1062             m_internal->Cancel();
1063         }
1064
1065 #if wxUSE_GUI
1066         // we can't just wait for the thread to terminate because it might be
1067         // calling some GUI functions and so it will never terminate before we
1068         // process the Windows messages that result from these functions
1069         DWORD result;
1070         do
1071         {
1072             result = ::MsgWaitForMultipleObjects
1073                      (
1074                        1,              // number of objects to wait for
1075                        &hThread,       // the objects
1076                        FALSE,          // don't wait for all objects
1077                        INFINITE,       // no timeout
1078                        QS_ALLEVENTS    // return as soon as there are any events
1079                      );
1080
1081             switch ( result )
1082             {
1083                 case 0xFFFFFFFF:
1084                     // error
1085                     wxLogSysError(_("Can not wait for thread termination"));
1086                     Kill();
1087                     return wxTHREAD_KILLED;
1088
1089                 case WAIT_OBJECT_0:
1090                     // thread we're waiting for terminated
1091                     break;
1092
1093                 case WAIT_OBJECT_0 + 1:
1094                     // new message arrived, process it
1095                     if ( !wxTheApp->DoMessage() )
1096                     {
1097                         // WM_QUIT received: kill the thread
1098                         Kill();
1099
1100                         return wxTHREAD_KILLED;
1101                     }
1102
1103                     if ( IsMain() )
1104                     {
1105                         // give the thread we're waiting for chance to exit
1106                         // from the GUI call it might have been in
1107                         if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
1108                         {
1109                             wxMutexGuiLeave();
1110                         }
1111                     }
1112
1113                     break;
1114
1115                 default:
1116                     wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
1117             }
1118         } while ( result != WAIT_OBJECT_0 );
1119 #else // !wxUSE_GUI
1120         // simply wait for the thread to terminate
1121         //
1122         // OTOH, even console apps create windows (in wxExecute, for WinSock
1123         // &c), so may be use MsgWaitForMultipleObject() too here?
1124         if ( WaitForSingleObject(hThread, INFINITE) != WAIT_OBJECT_0 )
1125         {
1126             wxFAIL_MSG(wxT("unexpected result of WaitForSingleObject"));
1127         }
1128 #endif // wxUSE_GUI/!wxUSE_GUI
1129
1130         if ( IsMain() )
1131         {
1132             gs_waitingForThread = FALSE;
1133
1134 #if wxUSE_GUI
1135             wxEndBusyCursor();
1136 #endif // wxUSE_GUI
1137         }
1138     }
1139
1140     // although the thread might be already in the EXITED state it might not
1141     // have terminated yet and so we are not sure that it has actually
1142     // terminated if the "if" above hadn't been taken
1143     do
1144     {
1145         if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
1146         {
1147             wxLogLastError(wxT("GetExitCodeThread"));
1148
1149             rc = (ExitCode)-1;
1150         }
1151     } while ( (DWORD)rc == STILL_ACTIVE );
1152
1153     if ( IsDetached() )
1154     {
1155         // if the thread exits normally, this is done in WinThreadStart, but in
1156         // this case it would have been too early because
1157         // MsgWaitForMultipleObject() would fail if the thread handle was
1158         // closed while we were waiting on it, so we must do it here
1159         delete this;
1160     }
1161
1162     if ( pRc )
1163         *pRc = rc;
1164
1165     return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
1166 }
1167
1168 wxThreadError wxThread::Kill()
1169 {
1170     if ( !IsRunning() )
1171         return wxTHREAD_NOT_RUNNING;
1172
1173     if ( !::TerminateThread(m_internal->GetHandle(), (DWORD)-1) )
1174     {
1175         wxLogSysError(_("Couldn't terminate thread"));
1176
1177         return wxTHREAD_MISC_ERROR;
1178     }
1179
1180     m_internal->Free();
1181
1182     if ( IsDetached() )
1183     {
1184         delete this;
1185     }
1186
1187     return wxTHREAD_NO_ERROR;
1188 }
1189
1190 void wxThread::Exit(ExitCode status)
1191 {
1192     m_internal->Free();
1193
1194     if ( IsDetached() )
1195     {
1196         delete this;
1197     }
1198
1199 #ifdef wxUSE_BEGIN_THREAD
1200     _endthreadex((unsigned)status);
1201 #else // !VC++
1202     ::ExitThread((DWORD)status);
1203 #endif // VC++/!VC++
1204
1205     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1206 }
1207
1208 // priority setting
1209 // ----------------
1210
1211 void wxThread::SetPriority(unsigned int prio)
1212 {
1213     wxCriticalSectionLocker lock(m_critsect);
1214
1215     m_internal->SetPriority(prio);
1216 }
1217
1218 unsigned int wxThread::GetPriority() const
1219 {
1220     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1221
1222     return m_internal->GetPriority();
1223 }
1224
1225 unsigned long wxThread::GetId() const
1226 {
1227     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1228
1229     return (unsigned long)m_internal->GetId();
1230 }
1231
1232 bool wxThread::IsRunning() const
1233 {
1234     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1235
1236     return m_internal->GetState() == STATE_RUNNING;
1237 }
1238
1239 bool wxThread::IsAlive() const
1240 {
1241     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1242
1243     return (m_internal->GetState() == STATE_RUNNING) ||
1244            (m_internal->GetState() == STATE_PAUSED);
1245 }
1246
1247 bool wxThread::IsPaused() const
1248 {
1249     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1250
1251     return m_internal->GetState() == STATE_PAUSED;
1252 }
1253
1254 bool wxThread::TestDestroy()
1255 {
1256     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1257
1258     return m_internal->GetState() == STATE_CANCELED;
1259 }
1260
1261 // ----------------------------------------------------------------------------
1262 // Automatic initialization for thread module
1263 // ----------------------------------------------------------------------------
1264
1265 class wxThreadModule : public wxModule
1266 {
1267 public:
1268     virtual bool OnInit();
1269     virtual void OnExit();
1270
1271 private:
1272     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1273 };
1274
1275 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1276
1277 bool wxThreadModule::OnInit()
1278 {
1279     // allocate TLS index for storing the pointer to the current thread
1280     gs_tlsThisThread = ::TlsAlloc();
1281     if ( gs_tlsThisThread == 0xFFFFFFFF )
1282     {
1283         // in normal circumstances it will only happen if all other
1284         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1285         // words, this should never happen
1286         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1287
1288         return FALSE;
1289     }
1290
1291     // main thread doesn't have associated wxThread object, so store 0 in the
1292     // TLS instead
1293     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1294     {
1295         ::TlsFree(gs_tlsThisThread);
1296         gs_tlsThisThread = 0xFFFFFFFF;
1297
1298         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1299
1300         return FALSE;
1301     }
1302
1303     gs_critsectWaitingForGui = new wxCriticalSection();
1304
1305     gs_critsectGui = new wxCriticalSection();
1306     gs_critsectGui->Enter();
1307
1308     // no error return for GetCurrentThreadId()
1309     gs_idMainThread = ::GetCurrentThreadId();
1310
1311     return TRUE;
1312 }
1313
1314 void wxThreadModule::OnExit()
1315 {
1316     if ( !::TlsFree(gs_tlsThisThread) )
1317     {
1318         wxLogLastError(wxT("TlsFree failed."));
1319     }
1320
1321     if ( gs_critsectGui )
1322     {
1323         gs_critsectGui->Leave();
1324         delete gs_critsectGui;
1325         gs_critsectGui = NULL;
1326     }
1327
1328     delete gs_critsectWaitingForGui;
1329     gs_critsectWaitingForGui = NULL;
1330 }
1331
1332 // ----------------------------------------------------------------------------
1333 // under Windows, these functions are implemented using a critical section and
1334 // not a mutex, so the names are a bit confusing
1335 // ----------------------------------------------------------------------------
1336
1337 void WXDLLEXPORT wxMutexGuiEnter()
1338 {
1339     // this would dead lock everything...
1340     wxASSERT_MSG( !wxThread::IsMain(),
1341                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1342
1343     // the order in which we enter the critical sections here is crucial!!
1344
1345     // set the flag telling to the main thread that we want to do some GUI
1346     {
1347         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1348
1349         gs_nWaitingForGui++;
1350     }
1351
1352     wxWakeUpMainThread();
1353
1354     // now we may block here because the main thread will soon let us in
1355     // (during the next iteration of OnIdle())
1356     gs_critsectGui->Enter();
1357 }
1358
1359 void WXDLLEXPORT wxMutexGuiLeave()
1360 {
1361     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1362
1363     if ( wxThread::IsMain() )
1364     {
1365         gs_bGuiOwnedByMainThread = FALSE;
1366     }
1367     else
1368     {
1369         // decrement the number of threads waiting for GUI access now
1370         wxASSERT_MSG( gs_nWaitingForGui > 0,
1371                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1372
1373         gs_nWaitingForGui--;
1374
1375         wxWakeUpMainThread();
1376     }
1377
1378     gs_critsectGui->Leave();
1379 }
1380
1381 void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
1382 {
1383     wxASSERT_MSG( wxThread::IsMain(),
1384                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1385
1386     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1387
1388     if ( gs_nWaitingForGui == 0 )
1389     {
1390         // no threads are waiting for GUI - so we may acquire the lock without
1391         // any danger (but only if we don't already have it)
1392         if ( !wxGuiOwnedByMainThread() )
1393         {
1394             gs_critsectGui->Enter();
1395
1396             gs_bGuiOwnedByMainThread = TRUE;
1397         }
1398         //else: already have it, nothing to do
1399     }
1400     else
1401     {
1402         // some threads are waiting, release the GUI lock if we have it
1403         if ( wxGuiOwnedByMainThread() )
1404         {
1405             wxMutexGuiLeave();
1406         }
1407         //else: some other worker thread is doing GUI
1408     }
1409 }
1410
1411 bool WXDLLEXPORT wxGuiOwnedByMainThread()
1412 {
1413     return gs_bGuiOwnedByMainThread;
1414 }
1415
1416 // wake up the main thread if it's in ::GetMessage()
1417 void WXDLLEXPORT wxWakeUpMainThread()
1418 {
1419     // sending any message would do - hopefully WM_NULL is harmless enough
1420     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1421     {
1422         // should never happen
1423         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1424     }
1425 }
1426
1427 bool WXDLLEXPORT wxIsWaitingForThread()
1428 {
1429     return gs_waitingForThread;
1430 }
1431
1432 #endif // wxUSE_THREADS
1433
1434 // vi:sts=4:sw=4:et