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 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  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/intl.h"
  30     #include "wx/app.h"
  31 #endif
  32
  33 #if wxUSE_THREADS
  34
  35 #include "wx/apptrait.h"
  36
  37 #include "wx/msw/private.h"
  38 #include "wx/msw/missing.h"
  39
  40 #include "wx/module.h"
  41 #include "wx/thread.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 #endif
 359     {
 360         wxLogLastError(_T("ReleaseSemaphore"));
 361
 362         return wxSEMA_MISC_ERROR;
 363     }
 364
 365     return wxSEMA_NO_ERROR;
 366 }
 367
 368 // ----------------------------------------------------------------------------
 369 // wxThread implementation
 370 // ----------------------------------------------------------------------------
 371
 372 // wxThreadInternal class
 373 // ----------------------
 374
 375 class wxThreadInternal
 376 {
 377 public:
 378     wxThreadInternal(wxThread *thread)
 379     {
 380         m_thread = thread;
 381         m_hThread = 0;
 382         m_state = STATE_NEW;
 383         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 384         m_nRef = 1;
 385     }
 386
 387     ~wxThreadInternal()
 388     {
 389         Free();
 390     }
 391
 392     void Free()
 393     {
 394         if ( m_hThread )
 395         {
 396             if ( !::CloseHandle(m_hThread) )
 397             {
 398                 wxLogLastError(wxT("CloseHandle(thread)"));
 399             }
 400
 401             m_hThread = 0;
 402         }
 403     }
 404
 405     // create a new (suspended) thread (for the given thread object)
 406     bool Create(wxThread *thread, unsigned int stackSize);
 407
 408     // wait for the thread to terminate, either by itself, or by asking it
 409     // (politely, this is not Kill()!) to do it
 410     wxThreadError WaitForTerminate(wxCriticalSection& cs,
 411                                    wxThread::ExitCode *pRc,
 412                                    wxThread *threadToDelete = NULL);
 413
 414     // kill the thread unconditionally
 415     wxThreadError Kill();
 416
 417     // suspend/resume/terminate
 418     bool Suspend();
 419     bool Resume();
 420     void Cancel() { m_state = STATE_CANCELED; }
 421
 422     // thread state
 423     void SetState(wxThreadState state) { m_state = state; }
 424     wxThreadState GetState() const { return m_state; }
 425
 426     // thread priority
 427     void SetPriority(unsigned int priority);
 428     unsigned int GetPriority() const { return m_priority; }
 429
 430     // thread handle and id
 431     HANDLE GetHandle() const { return m_hThread; }
 432     DWORD  GetId() const { return m_tid; }
 433
 434     // thread function
 435     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 436
 437     void KeepAlive()
 438     {
 439         if ( m_thread->IsDetached() )
 440             ::InterlockedIncrement(&m_nRef);
 441     }
 442
 443     void LetDie()
 444     {
 445         if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
 446             delete m_thread;
 447     }
 448
 449 private:
 450     // the thread we're associated with
 451     wxThread *m_thread;
 452
 453     HANDLE        m_hThread;    // handle of the thread
 454     wxThreadState m_state;      // state, see wxThreadState enum
 455     unsigned int  m_priority;   // thread priority in "wx" units
 456     DWORD         m_tid;        // thread id
 457
 458     // number of threads which need this thread to remain alive, when the count
 459     // reaches 0 we kill the owning wxThread -- and die ourselves with it
 460     LONG m_nRef;
 461
 462     DECLARE_NO_COPY_CLASS(wxThreadInternal)
 463 };
 464
 465 // small class which keeps a thread alive during its lifetime
 466 class wxThreadKeepAlive
 467 {
 468 public:
 469     wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
 470         { m_thrImpl.KeepAlive(); }
 471     ~wxThreadKeepAlive()
 472         { m_thrImpl.LetDie(); }
 473
 474 private:
 475     wxThreadInternal& m_thrImpl;
 476 };
 477
 478
 479 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 480 {
 481     THREAD_RETVAL rc;
 482
 483     wxThread * const thread = (wxThread *)param;
 484
 485     // first of all, check whether we hadn't been cancelled already and don't
 486     // start the user code at all then
 487     bool isExited = (thread->m_internal->GetState() == STATE_EXITED);
 488
 489     if ( isExited )
 490     {
 491         rc = (THREAD_RETVAL)-1;
 492     }
 493     else // do run thread
 494     {
 495         // store the thread object in the TLS
 496         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 497         {
 498             wxLogSysError(_("Can not start thread: error writing TLS."));
 499
 500             return (DWORD)-1;
 501         }
 502
 503         rc = (THREAD_RETVAL)thread->Entry();
 504     }
 505
 506     thread->OnExit();
 507
 508     // save IsDetached because thread object can be deleted by joinable
 509     // threads after state is changed to STATE_EXITED.
 510     bool isDetached = thread->IsDetached();
 511
 512     if (!isExited)
 513     {
 514         // enter m_critsect before changing the thread state
 515         wxCriticalSectionLocker lock(thread->m_critsect);
 516         thread->m_internal->SetState(STATE_EXITED);
 517     }
 518
 519     // the thread may delete itself now if it wants, we don't need it any more
 520     if (isDetached) thread->m_internal->LetDie();
 521
 522     return rc;
 523 }
 524
 525 void wxThreadInternal::SetPriority(unsigned int priority)
 526 {
 527     m_priority = priority;
 528
 529     // translate wxWindows priority to the Windows one
 530     int win_priority;
 531     if (m_priority <= 20)
 532         win_priority = THREAD_PRIORITY_LOWEST;
 533     else if (m_priority <= 40)
 534         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 535     else if (m_priority <= 60)
 536         win_priority = THREAD_PRIORITY_NORMAL;
 537     else if (m_priority <= 80)
 538         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 539     else if (m_priority <= 100)
 540         win_priority = THREAD_PRIORITY_HIGHEST;
 541     else
 542     {
 543         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 544         win_priority = THREAD_PRIORITY_NORMAL;
 545     }
 546
 547     if ( !::SetThreadPriority(m_hThread, win_priority) )
 548     {
 549         wxLogSysError(_("Can't set thread priority"));
 550     }
 551 }
 552
 553 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 554 {
 555     wxASSERT_MSG( m_state == STATE_NEW && !m_hThread,
 556                     _T("Create()ing thread twice?") );
 557
 558     // for compilers which have it, we should use C RTL function for thread
 559     // creation instead of Win32 API one because otherwise we will have memory
 560     // leaks if the thread uses C RTL (and most threads do)
 561 #ifdef wxUSE_BEGIN_THREAD
 562
 563     // Watcom is reported to not like 0 stack size (which means "use default"
 564     // for the other compilers and is also the default value for stackSize)
 565 #ifdef __WATCOMC__
 566     if ( !stackSize )
 567         stackSize = 10240;
 568 #endif // __WATCOMC__
 569
 570     m_hThread = (HANDLE)_beginthreadex
 571                         (
 572                           NULL,                             // default security
 573                           stackSize,
 574                           wxThreadInternal::WinThreadStart, // entry point
 575                           thread,
 576                           CREATE_SUSPENDED,
 577                           (unsigned int *)&m_tid
 578                         );
 579 #else // compiler doesn't have _beginthreadex
 580     m_hThread = ::CreateThread
 581                   (
 582                     NULL,                               // default security
 583                     stackSize,                          // stack size
 584                     wxThreadInternal::WinThreadStart,   // thread entry point
 585                     (LPVOID)thread,                     // parameter
 586                     CREATE_SUSPENDED,                   // flags
 587                     &m_tid                              // [out] thread id
 588                   );
 589 #endif // _beginthreadex/CreateThread
 590
 591     if ( m_hThread == NULL )
 592     {
 593         wxLogSysError(_("Can't create thread"));
 594
 595         return false;
 596     }
 597
 598     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 599     {
 600         SetPriority(m_priority);
 601     }
 602
 603     return true;
 604 }
 605
 606 wxThreadError wxThreadInternal::Kill()
 607 {
 608     if ( !::TerminateThread(m_hThread, (DWORD)-1) )
 609     {
 610         wxLogSysError(_("Couldn't terminate thread"));
 611
 612         return wxTHREAD_MISC_ERROR;
 613     }
 614
 615     Free();
 616
 617     return wxTHREAD_NO_ERROR;
 618 }
 619
 620 wxThreadError
 621 wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
 622                                    wxThread::ExitCode *pRc,
 623                                    wxThread *threadToDelete)
 624 {
 625     // prevent the thread C++ object from disappearing as long as we are using
 626     // it here
 627     wxThreadKeepAlive keepAlive(*this);
 628
 629
 630     // we may either wait passively for the thread to terminate (when called
 631     // from Wait()) or ask it to terminate (when called from Delete())
 632     bool shouldDelete = threadToDelete != NULL;
 633
 634     wxThread::ExitCode rc = 0;
 635
 636     // Delete() is always safe to call, so consider all possible states
 637
 638     // we might need to resume the thread, but we might also not need to cancel
 639     // it if it doesn't run yet
 640     bool shouldResume = false,
 641          isRunning = false;
 642
 643     // check if the thread already started to run
 644     {
 645         wxCriticalSectionLocker lock(cs);
 646
 647         if ( m_state == STATE_NEW )
 648         {
 649             if ( shouldDelete )
 650             {
 651                 // WinThreadStart() will see it and terminate immediately, no
 652                 // need to cancel the thread -- but we still need to resume it
 653                 // to let it run
 654                 m_state = STATE_EXITED;
 655
 656                 Resume();   // it knows about STATE_EXITED special case
 657
 658                 shouldDelete = false;
 659             }
 660
 661             isRunning = true;
 662
 663             // shouldResume is correctly set to false here
 664         }
 665         else if ( m_state == STATE_EXITED )
 666         {
 667             return wxTHREAD_NOT_RUNNING;
 668         }
 669         else // running (but maybe paused or cancelled)
 670         {
 671             shouldResume = m_state == STATE_PAUSED;
 672         }
 673     }
 674
 675     // resume the thread if it is paused
 676     if ( shouldResume )
 677         Resume();
 678
 679     // is it still running?
 680     if ( isRunning || m_state == STATE_RUNNING )
 681     {
 682         if ( wxThread::IsMain() )
 683         {
 684             // set flag for wxIsWaitingForThread()
 685             gs_waitingForThread = true;
 686         }
 687
 688         // ask the thread to terminate
 689         if ( shouldDelete )
 690         {
 691             wxCriticalSectionLocker lock(cs);
 692
 693             Cancel();
 694         }
 695
 696         // we can't just wait for the thread to terminate because it might be
 697         // calling some GUI functions and so it will never terminate before we
 698         // process the Windows messages that result from these functions
 699         // (note that even in console applications we might have to process
 700         // messages if we use wxExecute() or timers or ...)
 701         DWORD result wxDUMMY_INITIALIZE(0);
 702         do
 703         {
 704             if ( wxThread::IsMain() )
 705             {
 706                 // give the thread we're waiting for chance to do the GUI call
 707                 // it might be in
 708                 if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 709                 {
 710                     wxMutexGuiLeave();
 711                 }
 712             }
 713
 714             result = ::MsgWaitForMultipleObjects
 715                      (
 716                        1,              // number of objects to wait for
 717                        &m_hThread,     // the objects
 718                        false,          // don't wait for all objects
 719                        INFINITE,       // no timeout
 720                        QS_ALLINPUT |   // return as soon as there are any events
 721                        QS_ALLPOSTMESSAGE
 722                      );
 723
 724             switch ( result )
 725             {
 726                 case 0xFFFFFFFF:
 727                     // error
 728                     wxLogSysError(_("Can not wait for thread termination"));
 729                     Kill();
 730                     return wxTHREAD_KILLED;
 731
 732                 case WAIT_OBJECT_0:
 733                     // thread we're waiting for terminated
 734                     break;
 735
 736                 case WAIT_OBJECT_0 + 1:
 737                     // new message arrived, process it -- but only if we're the
 738                     // main thread as we don't support processing messages in
 739                     // the other ones
 740                     //
 741                     // NB: we still must include QS_ALLINPUT even when waiting
 742                     //     in a secondary thread because if it had created some
 743                     //     window somehow (possible not even using wxWindows)
 744                     //     the system might dead lock then
 745                     if ( wxThread::IsMain() )
 746                     {
 747                         // it looks that sometimes WAIT_OBJECT_0 + 1 is
 748                         // returned but there are no messages in the thread
 749                         // queue -- prevent DoMessageFromThreadWait() from
 750                         // blocking inside ::GetMessage() forever in this case
 751                         ::PostMessage(NULL, WM_NULL, 0, 0);
 752
 753                         wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits()
 754                                                        : NULL;
 755
 756                         if ( traits && !traits->DoMessageFromThreadWait() )
 757                         {
 758                             // WM_QUIT received: kill the thread
 759                             Kill();
 760
 761                             return wxTHREAD_KILLED;
 762                         }
 763                     }
 764                     break;
 765
 766                 default:
 767                     wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
 768             }
 769         } while ( result != WAIT_OBJECT_0 );
 770
 771         if ( wxThread::IsMain() )
 772         {
 773             gs_waitingForThread = false;
 774         }
 775     }
 776
 777     // although the thread might be already in the EXITED state it might not
 778     // have terminated yet and so we are not sure that it has actually
 779     // terminated if the "if" above hadn't been taken
 780     for ( ;; )
 781     {
 782         if ( !::GetExitCodeThread(m_hThread, (LPDWORD)&rc) )
 783         {
 784             wxLogLastError(wxT("GetExitCodeThread"));
 785
 786             rc = (wxThread::ExitCode)-1;
 787
 788             break;
 789         }
 790
 791         if ( (DWORD)rc != STILL_ACTIVE )
 792             break;
 793
 794         // give the other thread some time to terminate, otherwise we may be
 795         // starving it
 796         ::Sleep(1);
 797     }
 798
 799     if ( pRc )
 800         *pRc = rc;
 801
 802     // we don't need the thread handle any more in any case
 803     Free();
 804
 805
 806     return rc == (wxThread::ExitCode)-1 ? wxTHREAD_MISC_ERROR
 807                                         : wxTHREAD_NO_ERROR;
 808 }
 809
 810 bool wxThreadInternal::Suspend()
 811 {
 812     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 813     if ( nSuspendCount == (DWORD)-1 )
 814     {
 815         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 816
 817         return false;
 818     }
 819
 820     m_state = STATE_PAUSED;
 821
 822     return true;
 823 }
 824
 825 bool wxThreadInternal::Resume()
 826 {
 827     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 828     if ( nSuspendCount == (DWORD)-1 )
 829     {
 830         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 831
 832         return false;
 833     }
 834
 835     // don't change the state from STATE_EXITED because it's special and means
 836     // we are going to terminate without running any user code - if we did it,
 837     // the codei n Delete() wouldn't work
 838     if ( m_state != STATE_EXITED )
 839     {
 840         m_state = STATE_RUNNING;
 841     }
 842
 843     return true;
 844 }
 845
 846 // static functions
 847 // ----------------
 848
 849 wxThread *wxThread::This()
 850 {
 851     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 852
 853     // be careful, 0 may be a valid return value as well
 854     if ( !thread && (::GetLastError() != NO_ERROR) )
 855     {
 856         wxLogSysError(_("Couldn't get the current thread pointer"));
 857
 858         // return NULL...
 859     }
 860
 861     return thread;
 862 }
 863
 864 bool wxThread::IsMain()
 865 {
 866     return ::GetCurrentThreadId() == gs_idMainThread;
 867 }
 868
 869 void wxThread::Yield()
 870 {
 871     // 0 argument to Sleep() is special and means to just give away the rest of
 872     // our timeslice
 873     ::Sleep(0);
 874 }
 875
 876 void wxThread::Sleep(unsigned long milliseconds)
 877 {
 878     ::Sleep(milliseconds);
 879 }
 880
 881 int wxThread::GetCPUCount()
 882 {
 883     SYSTEM_INFO si;
 884     GetSystemInfo(&si);
 885
 886     return si.dwNumberOfProcessors;
 887 }
 888
 889 unsigned long wxThread::GetCurrentId()
 890 {
 891     return (unsigned long)::GetCurrentThreadId();
 892 }
 893
 894 bool wxThread::SetConcurrency(size_t level)
 895 {
 896 #ifndef __WXWINCE__
 897     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 898
 899     // ok only for the default one
 900     if ( level == 0 )
 901         return 0;
 902
 903     // get system affinity mask first
 904     HANDLE hProcess = ::GetCurrentProcess();
 905     DWORD dwProcMask, dwSysMask;
 906     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 907     {
 908         wxLogLastError(_T("GetProcessAffinityMask"));
 909
 910         return false;
 911     }
 912
 913     // how many CPUs have we got?
 914     if ( dwSysMask == 1 )
 915     {
 916         // don't bother with all this complicated stuff - on a single
 917         // processor system it doesn't make much sense anyhow
 918         return level == 1;
 919     }
 920
 921     // calculate the process mask: it's a bit vector with one bit per
 922     // processor; we want to schedule the process to run on first level
 923     // CPUs
 924     DWORD bit = 1;
 925     while ( bit )
 926     {
 927         if ( dwSysMask & bit )
 928         {
 929             // ok, we can set this bit
 930             dwProcMask |= bit;
 931
 932             // another process added
 933             if ( !--level )
 934             {
 935                 // and that's enough
 936                 break;
 937             }
 938         }
 939
 940         // next bit
 941         bit <<= 1;
 942     }
 943
 944     // could we set all bits?
 945     if ( level != 0 )
 946     {
 947         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 948
 949         return false;
 950     }
 951
 952     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 953     // exist in Win9x, use RT binding instead
 954
 955     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
 956
 957     // can use static var because we're always in the main thread here
 958     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
 959
 960     if ( !pfnSetProcessAffinityMask )
 961     {
 962         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
 963         if ( hModKernel )
 964         {
 965             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
 966                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
 967         }
 968
 969         // we've discovered a MT version of Win9x!
 970         wxASSERT_MSG( pfnSetProcessAffinityMask,
 971                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
 972     }
 973
 974     if ( !pfnSetProcessAffinityMask )
 975     {
 976         // msg given above - do it only once
 977         return false;
 978     }
 979
 980     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
 981     {
 982         wxLogLastError(_T("SetProcessAffinityMask"));
 983
 984         return false;
 985     }
 986 #endif
 987     return true;
 988 }
 989
 990 // ctor and dtor
 991 // -------------
 992
 993 wxThread::wxThread(wxThreadKind kind)
 994 {
 995     m_internal = new wxThreadInternal(this);
 996
 997     m_isDetached = kind == wxTHREAD_DETACHED;
 998 }
 999
1000 wxThread::~wxThread()
1001 {
1002     delete m_internal;
1003 }
1004
1005 // create/start thread
1006 // -------------------
1007
1008 wxThreadError wxThread::Create(unsigned int stackSize)
1009 {
1010     wxCriticalSectionLocker lock(m_critsect);
1011
1012     if ( !m_internal->Create(this, stackSize) )
1013         return wxTHREAD_NO_RESOURCE;
1014
1015     return wxTHREAD_NO_ERROR;
1016 }
1017
1018 wxThreadError wxThread::Run()
1019 {
1020     wxCriticalSectionLocker lock(m_critsect);
1021
1022     if ( m_internal->GetState() != STATE_NEW )
1023     {
1024         // actually, it may be almost any state at all, not only STATE_RUNNING
1025         return wxTHREAD_RUNNING;
1026     }
1027
1028     // the thread has just been created and is still suspended - let it run
1029     return Resume();
1030 }
1031
1032 // suspend/resume thread
1033 // ---------------------
1034
1035 wxThreadError wxThread::Pause()
1036 {
1037     wxCriticalSectionLocker lock(m_critsect);
1038
1039     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1040 }
1041
1042 wxThreadError wxThread::Resume()
1043 {
1044     wxCriticalSectionLocker lock(m_critsect);
1045
1046     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1047 }
1048
1049 // stopping thread
1050 // ---------------
1051
1052 wxThread::ExitCode wxThread::Wait()
1053 {
1054     // although under Windows we can wait for any thread, it's an error to
1055     // wait for a detached one in wxWin API
1056     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
1057                  _T("wxThread::Wait(): can't wait for detached thread") );
1058
1059     ExitCode rc = (ExitCode)-1;
1060
1061     (void)m_internal->WaitForTerminate(m_critsect, &rc);
1062
1063     return rc;
1064 }
1065
1066 wxThreadError wxThread::Delete(ExitCode *pRc)
1067 {
1068     return m_internal->WaitForTerminate(m_critsect, pRc, this);
1069 }
1070
1071 wxThreadError wxThread::Kill()
1072 {
1073     if ( !IsRunning() )
1074         return wxTHREAD_NOT_RUNNING;
1075
1076     wxThreadError rc = m_internal->Kill();
1077
1078     if ( IsDetached() )
1079     {
1080         delete this;
1081     }
1082     else // joinable
1083     {
1084         // update the status of the joinable thread
1085         wxCriticalSectionLocker lock(m_critsect);
1086         m_internal->SetState(STATE_EXITED);
1087     }
1088
1089     return rc;
1090 }
1091
1092 void wxThread::Exit(ExitCode status)
1093 {
1094     m_internal->Free();
1095
1096     if ( IsDetached() )
1097     {
1098         delete this;
1099     }
1100     else // joinable
1101     {
1102         // update the status of the joinable thread
1103         wxCriticalSectionLocker lock(m_critsect);
1104         m_internal->SetState(STATE_EXITED);
1105     }
1106
1107 #ifdef wxUSE_BEGIN_THREAD
1108     _endthreadex((unsigned)status);
1109 #else // !VC++
1110     ::ExitThread((DWORD)status);
1111 #endif // VC++/!VC++
1112
1113     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1114 }
1115
1116 // priority setting
1117 // ----------------
1118
1119 void wxThread::SetPriority(unsigned int prio)
1120 {
1121     wxCriticalSectionLocker lock(m_critsect);
1122
1123     m_internal->SetPriority(prio);
1124 }
1125
1126 unsigned int wxThread::GetPriority() const
1127 {
1128     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1129
1130     return m_internal->GetPriority();
1131 }
1132
1133 unsigned long wxThread::GetId() const
1134 {
1135     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1136
1137     return (unsigned long)m_internal->GetId();
1138 }
1139
1140 bool wxThread::IsRunning() const
1141 {
1142     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1143
1144     return m_internal->GetState() == STATE_RUNNING;
1145 }
1146
1147 bool wxThread::IsAlive() const
1148 {
1149     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1150
1151     return (m_internal->GetState() == STATE_RUNNING) ||
1152            (m_internal->GetState() == STATE_PAUSED);
1153 }
1154
1155 bool wxThread::IsPaused() const
1156 {
1157     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1158
1159     return m_internal->GetState() == STATE_PAUSED;
1160 }
1161
1162 bool wxThread::TestDestroy()
1163 {
1164     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1165
1166     return m_internal->GetState() == STATE_CANCELED;
1167 }
1168
1169 // ----------------------------------------------------------------------------
1170 // Automatic initialization for thread module
1171 // ----------------------------------------------------------------------------
1172
1173 class wxThreadModule : public wxModule
1174 {
1175 public:
1176     virtual bool OnInit();
1177     virtual void OnExit();
1178
1179 private:
1180     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1181 };
1182
1183 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1184
1185 bool wxThreadModule::OnInit()
1186 {
1187     // allocate TLS index for storing the pointer to the current thread
1188     gs_tlsThisThread = ::TlsAlloc();
1189     if ( gs_tlsThisThread == 0xFFFFFFFF )
1190     {
1191         // in normal circumstances it will only happen if all other
1192         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1193         // words, this should never happen
1194         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1195
1196         return false;
1197     }
1198
1199     // main thread doesn't have associated wxThread object, so store 0 in the
1200     // TLS instead
1201     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1202     {
1203         ::TlsFree(gs_tlsThisThread);
1204         gs_tlsThisThread = 0xFFFFFFFF;
1205
1206         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1207
1208         return false;
1209     }
1210
1211     gs_critsectWaitingForGui = new wxCriticalSection();
1212
1213     gs_critsectGui = new wxCriticalSection();
1214     gs_critsectGui->Enter();
1215
1216     gs_critsectThreadDelete = new wxCriticalSection;
1217
1218     // no error return for GetCurrentThreadId()
1219     gs_idMainThread = ::GetCurrentThreadId();
1220
1221     return true;
1222 }
1223
1224 void wxThreadModule::OnExit()
1225 {
1226     if ( !::TlsFree(gs_tlsThisThread) )
1227     {
1228         wxLogLastError(wxT("TlsFree failed."));
1229     }
1230
1231     delete gs_critsectThreadDelete;
1232     gs_critsectThreadDelete = NULL;
1233
1234     if ( gs_critsectGui )
1235     {
1236         gs_critsectGui->Leave();
1237         delete gs_critsectGui;
1238         gs_critsectGui = NULL;
1239     }
1240
1241     delete gs_critsectWaitingForGui;
1242     gs_critsectWaitingForGui = NULL;
1243 }
1244
1245 // ----------------------------------------------------------------------------
1246 // under Windows, these functions are implemented using a critical section and
1247 // not a mutex, so the names are a bit confusing
1248 // ----------------------------------------------------------------------------
1249
1250 void WXDLLIMPEXP_BASE wxMutexGuiEnter()
1251 {
1252     // this would dead lock everything...
1253     wxASSERT_MSG( !wxThread::IsMain(),
1254                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1255
1256     // the order in which we enter the critical sections here is crucial!!
1257
1258     // set the flag telling to the main thread that we want to do some GUI
1259     {
1260         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1261
1262         gs_nWaitingForGui++;
1263     }
1264
1265     wxWakeUpMainThread();
1266
1267     // now we may block here because the main thread will soon let us in
1268     // (during the next iteration of OnIdle())
1269     gs_critsectGui->Enter();
1270 }
1271
1272 void WXDLLIMPEXP_BASE wxMutexGuiLeave()
1273 {
1274     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1275
1276     if ( wxThread::IsMain() )
1277     {
1278         gs_bGuiOwnedByMainThread = false;
1279     }
1280     else
1281     {
1282         // decrement the number of threads waiting for GUI access now
1283         wxASSERT_MSG( gs_nWaitingForGui > 0,
1284                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1285
1286         gs_nWaitingForGui--;
1287
1288         wxWakeUpMainThread();
1289     }
1290
1291     gs_critsectGui->Leave();
1292 }
1293
1294 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1295 {
1296     wxASSERT_MSG( wxThread::IsMain(),
1297                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1298
1299     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1300
1301     if ( gs_nWaitingForGui == 0 )
1302     {
1303         // no threads are waiting for GUI - so we may acquire the lock without
1304         // any danger (but only if we don't already have it)
1305         if ( !wxGuiOwnedByMainThread() )
1306         {
1307             gs_critsectGui->Enter();
1308
1309             gs_bGuiOwnedByMainThread = true;
1310         }
1311         //else: already have it, nothing to do
1312     }
1313     else
1314     {
1315         // some threads are waiting, release the GUI lock if we have it
1316         if ( wxGuiOwnedByMainThread() )
1317         {
1318             wxMutexGuiLeave();
1319         }
1320         //else: some other worker thread is doing GUI
1321     }
1322 }
1323
1324 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1325 {
1326     return gs_bGuiOwnedByMainThread;
1327 }
1328
1329 // wake up the main thread if it's in ::GetMessage()
1330 void WXDLLIMPEXP_BASE wxWakeUpMainThread()
1331 {
1332     // sending any message would do - hopefully WM_NULL is harmless enough
1333     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1334     {
1335         // should never happen
1336         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1337     }
1338 }
1339
1340 bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
1341 {
1342     return gs_waitingForThread;
1343 }
1344
1345 // ----------------------------------------------------------------------------
1346 // include common implementation code
1347 // ----------------------------------------------------------------------------
1348
1349 #include "wx/thrimpl.cpp"
1350
1351 #endif // wxUSE_THREADS
1352