src/msw/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/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 (1999-2002)
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 // ----------------------------------------------------------------------------
  14 // headers
  15 // ----------------------------------------------------------------------------
  16
  17 // For compilers that support precompilation, includes "wx.h".
  18 #include "wx/wxprec.h"
  19
  20 #if defined(__BORLANDC__)
  21     #pragma hdrstop
  22 #endif
  23
  24 #if wxUSE_THREADS
  25
  26 #include "wx/thread.h"
  27
  28 #ifndef WX_PRECOMP
  29     #include "wx/msw/missing.h"
  30     #include "wx/intl.h"
  31     #include "wx/app.h"
  32     #include "wx/module.h"
  33 #endif
  34
  35 #include "wx/apptrait.h"
  36 #include "wx/scopeguard.h"
  37
  38 #include "wx/msw/private.h"
  39 #include "wx/msw/seh.h"
  40
  41 #include "wx/except.h"
  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 #ifndef __WXWINCE__
  68     #undef wxUSE_BEGIN_THREAD
  69     #define wxUSE_BEGIN_THREAD
  70 #endif
  71
  72 #endif
  73
  74 #ifdef wxUSE_BEGIN_THREAD
  75     // this is where _beginthreadex() is declared
  76     #include <process.h>
  77
  78     // the return type of the thread function entry point
  79     typedef unsigned THREAD_RETVAL;
  80
  81     // the calling convention of the thread function entry point
  82     #define THREAD_CALLCONV __stdcall
  83 #else
  84     // the settings for CreateThread()
  85     typedef DWORD THREAD_RETVAL;
  86     #define THREAD_CALLCONV WINAPI
  87 #endif
  88
  89 // ----------------------------------------------------------------------------
  90 // constants
  91 // ----------------------------------------------------------------------------
  92
  93 // the possible states of the thread ("=>" shows all possible transitions from
  94 // this state)
  95 enum wxThreadState
  96 {
  97     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  98     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  99     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
 100     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
 101     STATE_EXITED        // thread is terminating
 102 };
 103
 104 // ----------------------------------------------------------------------------
 105 // this module globals
 106 // ----------------------------------------------------------------------------
 107
 108 // TLS index of the slot where we store the pointer to the current thread
 109 static DWORD gs_tlsThisThread = 0xFFFFFFFF;
 110
 111 // id of the main thread - the one which can call GUI functions without first
 112 // calling wxMutexGuiEnter()
 113 static DWORD gs_idMainThread = 0;
 114
 115 // if it's false, some secondary thread is holding the GUI lock
 116 static bool gs_bGuiOwnedByMainThread = true;
 117
 118 // critical section which controls access to all GUI functions: any secondary
 119 // thread (i.e. except the main one) must enter this crit section before doing
 120 // any GUI calls
 121 static wxCriticalSection *gs_critsectGui = NULL;
 122
 123 // critical section which protects gs_nWaitingForGui variable
 124 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
 125
 126 // critical section which serializes WinThreadStart() and WaitForTerminate()
 127 // (this is a potential bottleneck, we use a single crit sect for all threads
 128 // in the system, but normally time spent inside it should be quite short)
 129 static wxCriticalSection *gs_critsectThreadDelete = NULL;
 130
 131 // number of threads waiting for GUI in wxMutexGuiEnter()
 132 static size_t gs_nWaitingForGui = 0;
 133
 134 // are we waiting for a thread termination?
 135 static bool gs_waitingForThread = false;
 136
 137 // ============================================================================
 138 // Windows implementation of thread and related classes
 139 // ============================================================================
 140
 141 // ----------------------------------------------------------------------------
 142 // wxCriticalSection
 143 // ----------------------------------------------------------------------------
 144
 145 wxCriticalSection::wxCriticalSection()
 146 {
 147     wxCOMPILE_TIME_ASSERT( sizeof(CRITICAL_SECTION) <= sizeof(wxCritSectBuffer),
 148                            wxCriticalSectionBufferTooSmall );
 149
 150     ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
 151 }
 152
 153 wxCriticalSection::~wxCriticalSection()
 154 {
 155     ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
 156 }
 157
 158 void wxCriticalSection::Enter()
 159 {
 160     ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
 161 }
 162
 163 void wxCriticalSection::Leave()
 164 {
 165     ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
 166 }
 167
 168 // ----------------------------------------------------------------------------
 169 // wxMutex
 170 // ----------------------------------------------------------------------------
 171
 172 class wxMutexInternal
 173 {
 174 public:
 175     wxMutexInternal(wxMutexType mutexType);
 176     ~wxMutexInternal();
 177
 178     bool IsOk() const { return m_mutex != NULL; }
 179
 180     wxMutexError Lock() { return LockTimeout(INFINITE); }
 181     wxMutexError TryLock() { return LockTimeout(0); }
 182     wxMutexError Unlock();
 183
 184 private:
 185     wxMutexError LockTimeout(DWORD milliseconds);
 186
 187     HANDLE m_mutex;
 188
 189     DECLARE_NO_COPY_CLASS(wxMutexInternal)
 190 };
 191
 192 // all mutexes are recursive under Win32 so we don't use mutexType
 193 wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
 194 {
 195     // create a nameless (hence intra process and always private) mutex
 196     m_mutex = ::CreateMutex
 197                 (
 198                     NULL,       // default secutiry attributes
 199                     false,      // not initially locked
 200                     NULL        // no name
 201                 );
 202
 203     if ( !m_mutex )
 204     {
 205         wxLogLastError(_T("CreateMutex()"));
 206     }
 207 }
 208
 209 wxMutexInternal::~wxMutexInternal()
 210 {
 211     if ( m_mutex )
 212     {
 213         if ( !::CloseHandle(m_mutex) )
 214         {
 215             wxLogLastError(_T("CloseHandle(mutex)"));
 216         }
 217     }
 218 }
 219
 220 wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
 221 {
 222     DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
 223     if ( rc == WAIT_ABANDONED )
 224     {
 225         // the previous caller died without releasing the mutex, but now we can
 226         // really lock it
 227         wxLogDebug(_T("WaitForSingleObject() returned WAIT_ABANDONED"));
 228
 229         // use 0 timeout, normally we should always get it
 230         rc = ::WaitForSingleObject(m_mutex, 0);
 231     }
 232
 233     switch ( rc )
 234     {
 235         case WAIT_OBJECT_0:
 236             // ok
 237             break;
 238
 239         case WAIT_TIMEOUT:
 240             return wxMUTEX_BUSY;
 241
 242         case WAIT_ABANDONED:        // checked for above
 243         default:
 244             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 245             // fall through
 246
 247         case WAIT_FAILED:
 248             wxLogLastError(_T("WaitForSingleObject(mutex)"));
 249             return wxMUTEX_MISC_ERROR;
 250     }
 251
 252     return wxMUTEX_NO_ERROR;
 253 }
 254
 255 wxMutexError wxMutexInternal::Unlock()
 256 {
 257     if ( !::ReleaseMutex(m_mutex) )
 258     {
 259         wxLogLastError(_T("ReleaseMutex()"));
 260
 261         return wxMUTEX_MISC_ERROR;
 262     }
 263
 264     return wxMUTEX_NO_ERROR;
 265 }
 266
 267 // --------------------------------------------------------------------------
 268 // wxSemaphore
 269 // --------------------------------------------------------------------------
 270
 271 // a trivial wrapper around Win32 semaphore
 272 class wxSemaphoreInternal
 273 {
 274 public:
 275     wxSemaphoreInternal(int initialcount, int maxcount);
 276     ~wxSemaphoreInternal();
 277
 278     bool IsOk() const { return m_semaphore != NULL; }
 279
 280     wxSemaError Wait() { return WaitTimeout(INFINITE); }
 281
 282     wxSemaError TryWait()
 283     {
 284         wxSemaError rc = WaitTimeout(0);
 285         if ( rc == wxSEMA_TIMEOUT )
 286             rc = wxSEMA_BUSY;
 287
 288         return rc;
 289     }
 290
 291     wxSemaError WaitTimeout(unsigned long milliseconds);
 292
 293     wxSemaError Post();
 294
 295 private:
 296     HANDLE m_semaphore;
 297
 298     DECLARE_NO_COPY_CLASS(wxSemaphoreInternal)
 299 };
 300
 301 wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
 302 {
 303 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
 304     if ( maxcount == 0 )
 305     {
 306         // make it practically infinite
 307         maxcount = INT_MAX;
 308     }
 309
 310     m_semaphore = ::CreateSemaphore
 311                     (
 312                         NULL,           // default security attributes
 313                         initialcount,
 314                         maxcount,
 315                         NULL            // no name
 316                     );
 317 #endif
 318     if ( !m_semaphore )
 319     {
 320         wxLogLastError(_T("CreateSemaphore()"));
 321     }
 322 }
 323
 324 wxSemaphoreInternal::~wxSemaphoreInternal()
 325 {
 326     if ( m_semaphore )
 327     {
 328         if ( !::CloseHandle(m_semaphore) )
 329         {
 330             wxLogLastError(_T("CloseHandle(semaphore)"));
 331         }
 332     }
 333 }
 334
 335 wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long milliseconds)
 336 {
 337     DWORD rc = ::WaitForSingleObject( m_semaphore, milliseconds );
 338
 339     switch ( rc )
 340     {
 341         case WAIT_OBJECT_0:
 342            return wxSEMA_NO_ERROR;
 343
 344         case WAIT_TIMEOUT:
 345            return wxSEMA_TIMEOUT;
 346
 347         default:
 348             wxLogLastError(_T("WaitForSingleObject(semaphore)"));
 349     }
 350
 351     return wxSEMA_MISC_ERROR;
 352 }
 353
 354 wxSemaError wxSemaphoreInternal::Post()
 355 {
 356 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
 357     if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
 358     {
 359         if ( GetLastError() == ERROR_TOO_MANY_POSTS )
 360         {
 361             return wxSEMA_OVERFLOW;
 362         }
 363         else
 364         {
 365             wxLogLastError(_T("ReleaseSemaphore"));
 366             return wxSEMA_MISC_ERROR;
 367         }
 368     }
 369
 370     return wxSEMA_NO_ERROR;
 371 #else
 372     return wxSEMA_MISC_ERROR;
 373 #endif
 374 }
 375
 376 // ----------------------------------------------------------------------------
 377 // wxThread implementation
 378 // ----------------------------------------------------------------------------
 379
 380 // wxThreadInternal class
 381 // ----------------------
 382
 383 class wxThreadInternal
 384 {
 385 public:
 386     wxThreadInternal(wxThread *thread)
 387     {
 388         m_thread = thread;
 389         m_hThread = 0;
 390         m_state = STATE_NEW;
 391         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 392         m_nRef = 1;
 393     }
 394
 395     ~wxThreadInternal()
 396     {
 397         Free();
 398     }
 399
 400     void Free()
 401     {
 402         if ( m_hThread )
 403         {
 404             if ( !::CloseHandle(m_hThread) )
 405             {
 406                 wxLogLastError(wxT("CloseHandle(thread)"));
 407             }
 408
 409             m_hThread = 0;
 410         }
 411     }
 412
 413     // create a new (suspended) thread (for the given thread object)
 414     bool Create(wxThread *thread, unsigned int stackSize);
 415
 416     // wait for the thread to terminate, either by itself, or by asking it
 417     // (politely, this is not Kill()!) to do it
 418     wxThreadError WaitForTerminate(wxCriticalSection& cs,
 419                                    wxThread::ExitCode *pRc,
 420                                    wxThread *threadToDelete = NULL);
 421
 422     // kill the thread unconditionally
 423     wxThreadError Kill();
 424
 425     // suspend/resume/terminate
 426     bool Suspend();
 427     bool Resume();
 428     void Cancel() { m_state = STATE_CANCELED; }
 429
 430     // thread state
 431     void SetState(wxThreadState state) { m_state = state; }
 432     wxThreadState GetState() const { return m_state; }
 433
 434     // thread priority
 435     void SetPriority(unsigned int priority);
 436     unsigned int GetPriority() const { return m_priority; }
 437
 438     // thread handle and id
 439     HANDLE GetHandle() const { return m_hThread; }
 440     DWORD  GetId() const { return m_tid; }
 441
 442     // the thread function forwarding to DoThreadStart
 443     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 444
 445     // really start the thread (if it's not already dead)
 446     static THREAD_RETVAL DoThreadStart(wxThread *thread);
 447
 448     // call OnExit() on the thread
 449     static void DoThreadOnExit(wxThread *thread);
 450
 451
 452     void KeepAlive()
 453     {
 454         if ( m_thread->IsDetached() )
 455             ::InterlockedIncrement(&m_nRef);
 456     }
 457
 458     void LetDie()
 459     {
 460         if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
 461             delete m_thread;
 462     }
 463
 464 private:
 465     // the thread we're associated with
 466     wxThread *m_thread;
 467
 468     HANDLE        m_hThread;    // handle of the thread
 469     wxThreadState m_state;      // state, see wxThreadState enum
 470     unsigned int  m_priority;   // thread priority in "wx" units
 471     DWORD         m_tid;        // thread id
 472
 473     // number of threads which need this thread to remain alive, when the count
 474     // reaches 0 we kill the owning wxThread -- and die ourselves with it
 475     LONG m_nRef;
 476
 477     DECLARE_NO_COPY_CLASS(wxThreadInternal)
 478 };
 479
 480 // small class which keeps a thread alive during its lifetime
 481 class wxThreadKeepAlive
 482 {
 483 public:
 484     wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
 485         { m_thrImpl.KeepAlive(); }
 486     ~wxThreadKeepAlive()
 487         { m_thrImpl.LetDie(); }
 488
 489 private:
 490     wxThreadInternal& m_thrImpl;
 491 };
 492
 493 /* static */
 494 void wxThreadInternal::DoThreadOnExit(wxThread *thread)
 495 {
 496     wxTRY
 497     {
 498         thread->OnExit();
 499     }
 500     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 501 }
 502
 503 /* static */
 504 THREAD_RETVAL wxThreadInternal::DoThreadStart(wxThread *thread)
 505 {
 506     wxON_BLOCK_EXIT1(DoThreadOnExit, thread);
 507
 508     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 509
 510     wxTRY
 511     {
 512         // store the thread object in the TLS
 513         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 514         {
 515             wxLogSysError(_("Can not start thread: error writing TLS."));
 516
 517             return (THREAD_RETVAL)-1;
 518         }
 519
 520         rc = (THREAD_RETVAL)thread->Entry();
 521     }
 522     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 523
 524     return rc;
 525 }
 526
 527 /* static */
 528 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 529 {
 530     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 531
 532     wxThread * const thread = (wxThread *)param;
 533
 534     // each thread has its own SEH translator so install our own a.s.a.p.
 535     DisableAutomaticSETranslator();
 536
 537     // first of all, check whether we hadn't been cancelled already and don't
 538     // start the user code at all then
 539     const bool hasExited = thread->m_internal->GetState() == STATE_EXITED;
 540
 541     // run the thread function itself inside a SEH try/except block
 542     wxSEH_TRY
 543     {
 544         if ( hasExited )
 545             DoThreadOnExit(thread);
 546         else
 547             rc = DoThreadStart(thread);
 548     }
 549     wxSEH_HANDLE((THREAD_RETVAL)-1)
 550
 551
 552     // save IsDetached because thread object can be deleted by joinable
 553     // threads after state is changed to STATE_EXITED.
 554     const bool isDetached = thread->IsDetached();
 555     if ( !hasExited )
 556     {
 557         // enter m_critsect before changing the thread state
 558         //
 559         // NB: can't use wxCriticalSectionLocker here as we use SEH and it's
 560         //     incompatible with C++ object dtors
 561         thread->m_critsect.Enter();
 562         thread->m_internal->SetState(STATE_EXITED);
 563         thread->m_critsect.Leave();
 564     }
 565
 566     // the thread may delete itself now if it wants, we don't need it any more
 567     if ( isDetached )
 568         thread->m_internal->LetDie();
 569
 570     return rc;
 571 }
 572
 573 void wxThreadInternal::SetPriority(unsigned int priority)
 574 {
 575     m_priority = priority;
 576
 577     // translate wxWidgets priority to the Windows one
 578     int win_priority;
 579     if (m_priority <= 20)
 580         win_priority = THREAD_PRIORITY_LOWEST;
 581     else if (m_priority <= 40)
 582         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 583     else if (m_priority <= 60)
 584         win_priority = THREAD_PRIORITY_NORMAL;
 585     else if (m_priority <= 80)
 586         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 587     else if (m_priority <= 100)
 588         win_priority = THREAD_PRIORITY_HIGHEST;
 589     else
 590     {
 591         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 592         win_priority = THREAD_PRIORITY_NORMAL;
 593     }
 594
 595     if ( !::SetThreadPriority(m_hThread, win_priority) )
 596     {
 597         wxLogSysError(_("Can't set thread priority"));
 598     }
 599 }
 600
 601 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 602 {
 603     wxASSERT_MSG( m_state == STATE_NEW && !m_hThread,
 604                     _T("Create()ing thread twice?") );
 605
 606     // for compilers which have it, we should use C RTL function for thread
 607     // creation instead of Win32 API one because otherwise we will have memory
 608     // leaks if the thread uses C RTL (and most threads do)
 609 #ifdef wxUSE_BEGIN_THREAD
 610
 611     // Watcom is reported to not like 0 stack size (which means "use default"
 612     // for the other compilers and is also the default value for stackSize)
 613 #ifdef __WATCOMC__
 614     if ( !stackSize )
 615         stackSize = 10240;
 616 #endif // __WATCOMC__
 617
 618     m_hThread = (HANDLE)_beginthreadex
 619                         (
 620                           NULL,                             // default security
 621                           stackSize,
 622                           wxThreadInternal::WinThreadStart, // entry point
 623                           thread,
 624                           CREATE_SUSPENDED,
 625                           (unsigned int *)&m_tid
 626                         );
 627 #else // compiler doesn't have _beginthreadex
 628     m_hThread = ::CreateThread
 629                   (
 630                     NULL,                               // default security
 631                     stackSize,                          // stack size
 632                     wxThreadInternal::WinThreadStart,   // thread entry point
 633                     (LPVOID)thread,                     // parameter
 634                     CREATE_SUSPENDED,                   // flags
 635                     &m_tid                              // [out] thread id
 636                   );
 637 #endif // _beginthreadex/CreateThread
 638
 639     if ( m_hThread == NULL )
 640     {
 641         wxLogSysError(_("Can't create thread"));
 642
 643         return false;
 644     }
 645
 646     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 647     {
 648         SetPriority(m_priority);
 649     }
 650
 651     return true;
 652 }
 653
 654 wxThreadError wxThreadInternal::Kill()
 655 {
 656     if ( !::TerminateThread(m_hThread, (DWORD)-1) )
 657     {
 658         wxLogSysError(_("Couldn't terminate thread"));
 659
 660         return wxTHREAD_MISC_ERROR;
 661     }
 662
 663     Free();
 664
 665     return wxTHREAD_NO_ERROR;
 666 }
 667
 668 wxThreadError
 669 wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
 670                                    wxThread::ExitCode *pRc,
 671                                    wxThread *threadToDelete)
 672 {
 673     // prevent the thread C++ object from disappearing as long as we are using
 674     // it here
 675     wxThreadKeepAlive keepAlive(*this);
 676
 677
 678     // we may either wait passively for the thread to terminate (when called
 679     // from Wait()) or ask it to terminate (when called from Delete())
 680     bool shouldDelete = threadToDelete != NULL;
 681
 682     wxThread::ExitCode rc = 0;
 683
 684     // we might need to resume the thread if it's currently stopped
 685     bool shouldResume = false;
 686
 687     // as Delete() (which calls us) is always safe to call we need to consider
 688     // all possible states
 689     {
 690         wxCriticalSectionLocker lock(cs);
 691
 692         if ( m_state == STATE_NEW )
 693         {
 694             if ( shouldDelete )
 695             {
 696                 // WinThreadStart() will see it and terminate immediately, no
 697                 // need to cancel the thread -- but we still need to resume it
 698                 // to let it run
 699                 m_state = STATE_EXITED;
 700
 701                 // we must call Resume() as the thread hasn't been initially
 702                 // resumed yet (and as Resume() it knows about STATE_EXITED
 703                 // special case, it won't touch it and WinThreadStart() will
 704                 // just exit immediately)
 705                 shouldResume = true;
 706                 shouldDelete = false;
 707             }
 708             //else: shouldResume is correctly set to false here, wait until
 709             //      someone else runs the thread and it finishes
 710         }
 711         else // running, paused, cancelled or even exited
 712         {
 713             shouldResume = m_state == STATE_PAUSED;
 714         }
 715     }
 716
 717     // resume the thread if it is paused
 718     if ( shouldResume )
 719         Resume();
 720
 721     // ask the thread to terminate
 722     if ( shouldDelete )
 723     {
 724         wxCriticalSectionLocker lock(cs);
 725
 726         Cancel();
 727     }
 728
 729
 730     // now wait for thread to finish
 731     if ( wxThread::IsMain() )
 732     {
 733         // set flag for wxIsWaitingForThread()
 734         gs_waitingForThread = true;
 735     }
 736
 737     // we can't just wait for the thread to terminate because it might be
 738     // calling some GUI functions and so it will never terminate before we
 739     // process the Windows messages that result from these functions
 740     // (note that even in console applications we might have to process
 741     // messages if we use wxExecute() or timers or ...)
 742     DWORD result wxDUMMY_INITIALIZE(0);
 743     do
 744     {
 745         if ( wxThread::IsMain() )
 746         {
 747             // give the thread we're waiting for chance to do the GUI call
 748             // it might be in
 749             if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 750             {
 751                 wxMutexGuiLeave();
 752             }
 753         }
 754
 755 #if !defined(QS_ALLPOSTMESSAGE)
 756 #define QS_ALLPOSTMESSAGE 0
 757 #endif
 758
 759         result = ::MsgWaitForMultipleObjects
 760                  (
 761                    1,              // number of objects to wait for
 762                    &m_hThread,     // the objects
 763                    false,          // don't wait for all objects
 764                    INFINITE,       // no timeout
 765                    QS_ALLINPUT|QS_ALLPOSTMESSAGE   // return as soon as there are any events
 766                  );
 767
 768         switch ( result )
 769         {
 770             case 0xFFFFFFFF:
 771                 // error
 772                 wxLogSysError(_("Can not wait for thread termination"));
 773                 Kill();
 774                 return wxTHREAD_KILLED;
 775
 776             case WAIT_OBJECT_0:
 777                 // thread we're waiting for terminated
 778                 break;
 779
 780             case WAIT_OBJECT_0 + 1:
 781                 // new message arrived, process it -- but only if we're the
 782                 // main thread as we don't support processing messages in
 783                 // the other ones
 784                 //
 785                 // NB: we still must include QS_ALLINPUT even when waiting
 786                 //     in a secondary thread because if it had created some
 787                 //     window somehow (possible not even using wxWidgets)
 788                 //     the system might dead lock then
 789                 if ( wxThread::IsMain() )
 790                 {
 791                     wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits()
 792                                                    : NULL;
 793
 794                     if ( traits && !traits->DoMessageFromThreadWait() )
 795                     {
 796                         // WM_QUIT received: kill the thread
 797                         Kill();
 798
 799                         return wxTHREAD_KILLED;
 800                     }
 801                 }
 802                 break;
 803
 804             default:
 805                 wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
 806         }
 807     } while ( result != WAIT_OBJECT_0 );
 808
 809     if ( wxThread::IsMain() )
 810     {
 811         gs_waitingForThread = false;
 812     }
 813
 814
 815     // although the thread might be already in the EXITED state it might not
 816     // have terminated yet and so we are not sure that it has actually
 817     // terminated if the "if" above hadn't been taken
 818     for ( ;; )
 819     {
 820         if ( !::GetExitCodeThread(m_hThread, (LPDWORD)&rc) )
 821         {
 822             wxLogLastError(wxT("GetExitCodeThread"));
 823
 824             rc = (wxThread::ExitCode)-1;
 825
 826             break;
 827         }
 828
 829         if ( (DWORD)rc != STILL_ACTIVE )
 830             break;
 831
 832         // give the other thread some time to terminate, otherwise we may be
 833         // starving it
 834         ::Sleep(1);
 835     }
 836
 837     if ( pRc )
 838         *pRc = rc;
 839
 840     // we don't need the thread handle any more in any case
 841     Free();
 842
 843
 844     return rc == (wxThread::ExitCode)-1 ? wxTHREAD_MISC_ERROR
 845                                         : wxTHREAD_NO_ERROR;
 846 }
 847
 848 bool wxThreadInternal::Suspend()
 849 {
 850     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 851     if ( nSuspendCount == (DWORD)-1 )
 852     {
 853         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 854
 855         return false;
 856     }
 857
 858     m_state = STATE_PAUSED;
 859
 860     return true;
 861 }
 862
 863 bool wxThreadInternal::Resume()
 864 {
 865     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 866     if ( nSuspendCount == (DWORD)-1 )
 867     {
 868         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 869
 870         return false;
 871     }
 872
 873     // don't change the state from STATE_EXITED because it's special and means
 874     // we are going to terminate without running any user code - if we did it,
 875     // the code in WaitForTerminate() wouldn't work
 876     if ( m_state != STATE_EXITED )
 877     {
 878         m_state = STATE_RUNNING;
 879     }
 880
 881     return true;
 882 }
 883
 884 // static functions
 885 // ----------------
 886
 887 wxThread *wxThread::This()
 888 {
 889     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 890
 891     // be careful, 0 may be a valid return value as well
 892     if ( !thread && (::GetLastError() != NO_ERROR) )
 893     {
 894         wxLogSysError(_("Couldn't get the current thread pointer"));
 895
 896         // return NULL...
 897     }
 898
 899     return thread;
 900 }
 901
 902 bool wxThread::IsMain()
 903 {
 904     return ::GetCurrentThreadId() == gs_idMainThread || gs_idMainThread == 0;
 905 }
 906
 907 void wxThread::Yield()
 908 {
 909     // 0 argument to Sleep() is special and means to just give away the rest of
 910     // our timeslice
 911     ::Sleep(0);
 912 }
 913
 914 void wxThread::Sleep(unsigned long milliseconds)
 915 {
 916     ::Sleep(milliseconds);
 917 }
 918
 919 int wxThread::GetCPUCount()
 920 {
 921     SYSTEM_INFO si;
 922     GetSystemInfo(&si);
 923
 924     return si.dwNumberOfProcessors;
 925 }
 926
 927 unsigned long wxThread::GetCurrentId()
 928 {
 929     return (unsigned long)::GetCurrentThreadId();
 930 }
 931
 932 bool wxThread::SetConcurrency(size_t WXUNUSED_IN_WINCE(level))
 933 {
 934 #ifdef __WXWINCE__
 935     return false;
 936 #else
 937     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 938
 939     // ok only for the default one
 940     if ( level == 0 )
 941         return 0;
 942
 943     // get system affinity mask first
 944     HANDLE hProcess = ::GetCurrentProcess();
 945     DWORD_PTR dwProcMask, dwSysMask;
 946     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 947     {
 948         wxLogLastError(_T("GetProcessAffinityMask"));
 949
 950         return false;
 951     }
 952
 953     // how many CPUs have we got?
 954     if ( dwSysMask == 1 )
 955     {
 956         // don't bother with all this complicated stuff - on a single
 957         // processor system it doesn't make much sense anyhow
 958         return level == 1;
 959     }
 960
 961     // calculate the process mask: it's a bit vector with one bit per
 962     // processor; we want to schedule the process to run on first level
 963     // CPUs
 964     DWORD bit = 1;
 965     while ( bit )
 966     {
 967         if ( dwSysMask & bit )
 968         {
 969             // ok, we can set this bit
 970             dwProcMask |= bit;
 971
 972             // another process added
 973             if ( --level == 0 )
 974             {
 975                 // and that's enough
 976                 break;
 977             }
 978         }
 979
 980         // next bit
 981         bit <<= 1;
 982     }
 983
 984     // could we set all bits?
 985     if ( level != 0 )
 986     {
 987         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 988
 989         return false;
 990     }
 991
 992     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 993     // exist in Win9x, use RT binding instead
 994
 995     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
 996
 997     // can use static var because we're always in the main thread here
 998     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
 999
1000     if ( !pfnSetProcessAffinityMask )
1001     {
1002         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
1003         if ( hModKernel )
1004         {
1005             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
1006                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
1007         }
1008
1009         // we've discovered a MT version of Win9x!
1010         wxASSERT_MSG( pfnSetProcessAffinityMask,
1011                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
1012     }
1013
1014     if ( !pfnSetProcessAffinityMask )
1015     {
1016         // msg given above - do it only once
1017         return false;
1018     }
1019
1020     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
1021     {
1022         wxLogLastError(_T("SetProcessAffinityMask"));
1023
1024         return false;
1025     }
1026
1027     return true;
1028 #endif // __WXWINCE__/!__WXWINCE__
1029 }
1030
1031 // ctor and dtor
1032 // -------------
1033
1034 wxThread::wxThread(wxThreadKind kind)
1035 {
1036     m_internal = new wxThreadInternal(this);
1037
1038     m_isDetached = kind == wxTHREAD_DETACHED;
1039 }
1040
1041 wxThread::~wxThread()
1042 {
1043     delete m_internal;
1044 }
1045
1046 // create/start thread
1047 // -------------------
1048
1049 wxThreadError wxThread::Create(unsigned int stackSize)
1050 {
1051     wxCriticalSectionLocker lock(m_critsect);
1052
1053     if ( !m_internal->Create(this, stackSize) )
1054         return wxTHREAD_NO_RESOURCE;
1055
1056     return wxTHREAD_NO_ERROR;
1057 }
1058
1059 wxThreadError wxThread::Run()
1060 {
1061     wxCriticalSectionLocker lock(m_critsect);
1062
1063     if ( m_internal->GetState() != STATE_NEW )
1064     {
1065         // actually, it may be almost any state at all, not only STATE_RUNNING
1066         return wxTHREAD_RUNNING;
1067     }
1068
1069     // the thread has just been created and is still suspended - let it run
1070     return Resume();
1071 }
1072
1073 // suspend/resume thread
1074 // ---------------------
1075
1076 wxThreadError wxThread::Pause()
1077 {
1078     wxCriticalSectionLocker lock(m_critsect);
1079
1080     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1081 }
1082
1083 wxThreadError wxThread::Resume()
1084 {
1085     wxCriticalSectionLocker lock(m_critsect);
1086
1087     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1088 }
1089
1090 // stopping thread
1091 // ---------------
1092
1093 wxThread::ExitCode wxThread::Wait()
1094 {
1095     // although under Windows we can wait for any thread, it's an error to
1096     // wait for a detached one in wxWin API
1097     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
1098                  _T("wxThread::Wait(): can't wait for detached thread") );
1099
1100     ExitCode rc = (ExitCode)-1;
1101
1102     (void)m_internal->WaitForTerminate(m_critsect, &rc);
1103
1104     return rc;
1105 }
1106
1107 wxThreadError wxThread::Delete(ExitCode *pRc)
1108 {
1109     return m_internal->WaitForTerminate(m_critsect, pRc, this);
1110 }
1111
1112 wxThreadError wxThread::Kill()
1113 {
1114     if ( !IsRunning() )
1115         return wxTHREAD_NOT_RUNNING;
1116
1117     wxThreadError rc = m_internal->Kill();
1118
1119     if ( IsDetached() )
1120     {
1121         delete this;
1122     }
1123     else // joinable
1124     {
1125         // update the status of the joinable thread
1126         wxCriticalSectionLocker lock(m_critsect);
1127         m_internal->SetState(STATE_EXITED);
1128     }
1129
1130     return rc;
1131 }
1132
1133 void wxThread::Exit(ExitCode status)
1134 {
1135     m_internal->Free();
1136
1137     if ( IsDetached() )
1138     {
1139         delete this;
1140     }
1141     else // joinable
1142     {
1143         // update the status of the joinable thread
1144         wxCriticalSectionLocker lock(m_critsect);
1145         m_internal->SetState(STATE_EXITED);
1146     }
1147
1148 #ifdef wxUSE_BEGIN_THREAD
1149     _endthreadex((unsigned)status);
1150 #else // !VC++
1151     ::ExitThread((DWORD)status);
1152 #endif // VC++/!VC++
1153
1154     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1155 }
1156
1157 // priority setting
1158 // ----------------
1159
1160 void wxThread::SetPriority(unsigned int prio)
1161 {
1162     wxCriticalSectionLocker lock(m_critsect);
1163
1164     m_internal->SetPriority(prio);
1165 }
1166
1167 unsigned int wxThread::GetPriority() const
1168 {
1169     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1170
1171     return m_internal->GetPriority();
1172 }
1173
1174 unsigned long wxThread::GetId() const
1175 {
1176     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1177
1178     return (unsigned long)m_internal->GetId();
1179 }
1180
1181 bool wxThread::IsRunning() const
1182 {
1183     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1184
1185     return m_internal->GetState() == STATE_RUNNING;
1186 }
1187
1188 bool wxThread::IsAlive() const
1189 {
1190     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1191
1192     return (m_internal->GetState() == STATE_RUNNING) ||
1193            (m_internal->GetState() == STATE_PAUSED);
1194 }
1195
1196 bool wxThread::IsPaused() const
1197 {
1198     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1199
1200     return m_internal->GetState() == STATE_PAUSED;
1201 }
1202
1203 bool wxThread::TestDestroy()
1204 {
1205     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1206
1207     return m_internal->GetState() == STATE_CANCELED;
1208 }
1209
1210 // ----------------------------------------------------------------------------
1211 // Automatic initialization for thread module
1212 // ----------------------------------------------------------------------------
1213
1214 class wxThreadModule : public wxModule
1215 {
1216 public:
1217     virtual bool OnInit();
1218     virtual void OnExit();
1219
1220 private:
1221     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1222 };
1223
1224 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1225
1226 bool wxThreadModule::OnInit()
1227 {
1228     // allocate TLS index for storing the pointer to the current thread
1229     gs_tlsThisThread = ::TlsAlloc();
1230     if ( gs_tlsThisThread == 0xFFFFFFFF )
1231     {
1232         // in normal circumstances it will only happen if all other
1233         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1234         // words, this should never happen
1235         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1236
1237         return false;
1238     }
1239
1240     // main thread doesn't have associated wxThread object, so store 0 in the
1241     // TLS instead
1242     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1243     {
1244         ::TlsFree(gs_tlsThisThread);
1245         gs_tlsThisThread = 0xFFFFFFFF;
1246
1247         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1248
1249         return false;
1250     }
1251
1252     gs_critsectWaitingForGui = new wxCriticalSection();
1253
1254     gs_critsectGui = new wxCriticalSection();
1255     gs_critsectGui->Enter();
1256
1257     gs_critsectThreadDelete = new wxCriticalSection;
1258
1259     // no error return for GetCurrentThreadId()
1260     gs_idMainThread = ::GetCurrentThreadId();
1261
1262     return true;
1263 }
1264
1265 void wxThreadModule::OnExit()
1266 {
1267     if ( !::TlsFree(gs_tlsThisThread) )
1268     {
1269         wxLogLastError(wxT("TlsFree failed."));
1270     }
1271
1272     delete gs_critsectThreadDelete;
1273     gs_critsectThreadDelete = NULL;
1274
1275     if ( gs_critsectGui )
1276     {
1277         gs_critsectGui->Leave();
1278         delete gs_critsectGui;
1279         gs_critsectGui = NULL;
1280     }
1281
1282     delete gs_critsectWaitingForGui;
1283     gs_critsectWaitingForGui = NULL;
1284 }
1285
1286 // ----------------------------------------------------------------------------
1287 // under Windows, these functions are implemented using a critical section and
1288 // not a mutex, so the names are a bit confusing
1289 // ----------------------------------------------------------------------------
1290
1291 void WXDLLIMPEXP_BASE wxMutexGuiEnter()
1292 {
1293     // this would dead lock everything...
1294     wxASSERT_MSG( !wxThread::IsMain(),
1295                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1296
1297     // the order in which we enter the critical sections here is crucial!!
1298
1299     // set the flag telling to the main thread that we want to do some GUI
1300     {
1301         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1302
1303         gs_nWaitingForGui++;
1304     }
1305
1306     wxWakeUpMainThread();
1307
1308     // now we may block here because the main thread will soon let us in
1309     // (during the next iteration of OnIdle())
1310     gs_critsectGui->Enter();
1311 }
1312
1313 void WXDLLIMPEXP_BASE wxMutexGuiLeave()
1314 {
1315     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1316
1317     if ( wxThread::IsMain() )
1318     {
1319         gs_bGuiOwnedByMainThread = false;
1320     }
1321     else
1322     {
1323         // decrement the number of threads waiting for GUI access now
1324         wxASSERT_MSG( gs_nWaitingForGui > 0,
1325                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1326
1327         gs_nWaitingForGui--;
1328
1329         wxWakeUpMainThread();
1330     }
1331
1332     gs_critsectGui->Leave();
1333 }
1334
1335 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1336 {
1337     wxASSERT_MSG( wxThread::IsMain(),
1338                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1339
1340     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1341
1342     if ( gs_nWaitingForGui == 0 )
1343     {
1344         // no threads are waiting for GUI - so we may acquire the lock without
1345         // any danger (but only if we don't already have it)
1346         if ( !wxGuiOwnedByMainThread() )
1347         {
1348             gs_critsectGui->Enter();
1349
1350             gs_bGuiOwnedByMainThread = true;
1351         }
1352         //else: already have it, nothing to do
1353     }
1354     else
1355     {
1356         // some threads are waiting, release the GUI lock if we have it
1357         if ( wxGuiOwnedByMainThread() )
1358         {
1359             wxMutexGuiLeave();
1360         }
1361         //else: some other worker thread is doing GUI
1362     }
1363 }
1364
1365 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1366 {
1367     return gs_bGuiOwnedByMainThread;
1368 }
1369
1370 // wake up the main thread if it's in ::GetMessage()
1371 void WXDLLIMPEXP_BASE wxWakeUpMainThread()
1372 {
1373     // sending any message would do - hopefully WM_NULL is harmless enough
1374     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1375     {
1376         // should never happen
1377         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1378     }
1379 }
1380
1381 bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
1382 {
1383     return gs_waitingForThread;
1384 }
1385
1386 // ----------------------------------------------------------------------------
1387 // include common implementation code
1388 // ----------------------------------------------------------------------------
1389
1390 #include "wx/thrimpl.cpp"
1391
1392 #endif // wxUSE_THREADS