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/intl.h"
  30     #include "wx/app.h"
  31 #endif
  32
  33 #include "wx/apptrait.h"
  34 #include "wx/scopeguard.h"
  35
  36 #include "wx/msw/private.h"
  37 #include "wx/msw/missing.h"
  38 #include "wx/msw/seh.h"
  39
  40 #include "wx/except.h"
  41 #include "wx/module.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     // the thread function forwarding to DoThreadStart
 435     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 436
 437     // really start the thread (if it's not already dead)
 438     static THREAD_RETVAL DoThreadStart(wxThread *thread);
 439
 440     // call OnExit() on the thread
 441     static void DoThreadOnExit(wxThread *thread);
 442
 443
 444     void KeepAlive()
 445     {
 446         if ( m_thread->IsDetached() )
 447             ::InterlockedIncrement(&m_nRef);
 448     }
 449
 450     void LetDie()
 451     {
 452         if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
 453             delete m_thread;
 454     }
 455
 456 private:
 457     // the thread we're associated with
 458     wxThread *m_thread;
 459
 460     HANDLE        m_hThread;    // handle of the thread
 461     wxThreadState m_state;      // state, see wxThreadState enum
 462     unsigned int  m_priority;   // thread priority in "wx" units
 463     DWORD         m_tid;        // thread id
 464
 465     // number of threads which need this thread to remain alive, when the count
 466     // reaches 0 we kill the owning wxThread -- and die ourselves with it
 467     LONG m_nRef;
 468
 469     DECLARE_NO_COPY_CLASS(wxThreadInternal)
 470 };
 471
 472 // small class which keeps a thread alive during its lifetime
 473 class wxThreadKeepAlive
 474 {
 475 public:
 476     wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
 477         { m_thrImpl.KeepAlive(); }
 478     ~wxThreadKeepAlive()
 479         { m_thrImpl.LetDie(); }
 480
 481 private:
 482     wxThreadInternal& m_thrImpl;
 483 };
 484
 485 /* static */
 486 void wxThreadInternal::DoThreadOnExit(wxThread *thread)
 487 {
 488     wxTRY
 489     {
 490         thread->OnExit();
 491     }
 492     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 493 }
 494
 495 /* static */
 496 THREAD_RETVAL wxThreadInternal::DoThreadStart(wxThread *thread)
 497 {
 498     wxON_BLOCK_EXIT1(DoThreadOnExit, thread);
 499
 500     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 501
 502     wxTRY
 503     {
 504         // store the thread object in the TLS
 505         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 506         {
 507             wxLogSysError(_("Can not start thread: error writing TLS."));
 508
 509             return (THREAD_RETVAL)-1;
 510         }
 511
 512         rc = (THREAD_RETVAL)thread->Entry();
 513     }
 514     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 515
 516     return rc;
 517 }
 518
 519 /* static */
 520 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 521 {
 522     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 523
 524     wxThread * const thread = (wxThread *)param;
 525
 526     // each thread has its own SEH translator so install our own a.s.a.p.
 527     DisableAutomaticSETranslator();
 528
 529     // first of all, check whether we hadn't been cancelled already and don't
 530     // start the user code at all then
 531     const bool hasExited = thread->m_internal->GetState() == STATE_EXITED;
 532
 533     // run the thread function itself inside a SEH try/except block
 534     wxSEH_TRY
 535     {
 536         if ( hasExited )
 537             DoThreadOnExit(thread);
 538         else
 539             rc = DoThreadStart(thread);
 540     }
 541     wxSEH_HANDLE((THREAD_RETVAL)-1)
 542
 543
 544     // save IsDetached because thread object can be deleted by joinable
 545     // threads after state is changed to STATE_EXITED.
 546     const bool isDetached = thread->IsDetached();
 547     if ( !hasExited )
 548     {
 549         // enter m_critsect before changing the thread state
 550         //
 551         // NB: can't use wxCriticalSectionLocker here as we use SEH and it's
 552         //     incompatible with C++ object dtors
 553         thread->m_critsect.Enter();
 554         thread->m_internal->SetState(STATE_EXITED);
 555         thread->m_critsect.Leave();
 556     }
 557
 558     // the thread may delete itself now if it wants, we don't need it any more
 559     if ( isDetached )
 560         thread->m_internal->LetDie();
 561
 562     return rc;
 563 }
 564
 565 void wxThreadInternal::SetPriority(unsigned int priority)
 566 {
 567     m_priority = priority;
 568
 569     // translate wxWidgets priority to the Windows one
 570     int win_priority;
 571     if (m_priority <= 20)
 572         win_priority = THREAD_PRIORITY_LOWEST;
 573     else if (m_priority <= 40)
 574         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 575     else if (m_priority <= 60)
 576         win_priority = THREAD_PRIORITY_NORMAL;
 577     else if (m_priority <= 80)
 578         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 579     else if (m_priority <= 100)
 580         win_priority = THREAD_PRIORITY_HIGHEST;
 581     else
 582     {
 583         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 584         win_priority = THREAD_PRIORITY_NORMAL;
 585     }
 586
 587     if ( !::SetThreadPriority(m_hThread, win_priority) )
 588     {
 589         wxLogSysError(_("Can't set thread priority"));
 590     }
 591 }
 592
 593 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 594 {
 595     wxASSERT_MSG( m_state == STATE_NEW && !m_hThread,
 596                     _T("Create()ing thread twice?") );
 597
 598     // for compilers which have it, we should use C RTL function for thread
 599     // creation instead of Win32 API one because otherwise we will have memory
 600     // leaks if the thread uses C RTL (and most threads do)
 601 #ifdef wxUSE_BEGIN_THREAD
 602
 603     // Watcom is reported to not like 0 stack size (which means "use default"
 604     // for the other compilers and is also the default value for stackSize)
 605 #ifdef __WATCOMC__
 606     if ( !stackSize )
 607         stackSize = 10240;
 608 #endif // __WATCOMC__
 609
 610     m_hThread = (HANDLE)_beginthreadex
 611                         (
 612                           NULL,                             // default security
 613                           stackSize,
 614                           wxThreadInternal::WinThreadStart, // entry point
 615                           thread,
 616                           CREATE_SUSPENDED,
 617                           (unsigned int *)&m_tid
 618                         );
 619 #else // compiler doesn't have _beginthreadex
 620     m_hThread = ::CreateThread
 621                   (
 622                     NULL,                               // default security
 623                     stackSize,                          // stack size
 624                     wxThreadInternal::WinThreadStart,   // thread entry point
 625                     (LPVOID)thread,                     // parameter
 626                     CREATE_SUSPENDED,                   // flags
 627                     &m_tid                              // [out] thread id
 628                   );
 629 #endif // _beginthreadex/CreateThread
 630
 631     if ( m_hThread == NULL )
 632     {
 633         wxLogSysError(_("Can't create thread"));
 634
 635         return false;
 636     }
 637
 638     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 639     {
 640         SetPriority(m_priority);
 641     }
 642
 643     return true;
 644 }
 645
 646 wxThreadError wxThreadInternal::Kill()
 647 {
 648     if ( !::TerminateThread(m_hThread, (DWORD)-1) )
 649     {
 650         wxLogSysError(_("Couldn't terminate thread"));
 651
 652         return wxTHREAD_MISC_ERROR;
 653     }
 654
 655     Free();
 656
 657     return wxTHREAD_NO_ERROR;
 658 }
 659
 660 wxThreadError
 661 wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
 662                                    wxThread::ExitCode *pRc,
 663                                    wxThread *threadToDelete)
 664 {
 665     // prevent the thread C++ object from disappearing as long as we are using
 666     // it here
 667     wxThreadKeepAlive keepAlive(*this);
 668
 669
 670     // we may either wait passively for the thread to terminate (when called
 671     // from Wait()) or ask it to terminate (when called from Delete())
 672     bool shouldDelete = threadToDelete != NULL;
 673
 674     wxThread::ExitCode rc = 0;
 675
 676     // we might need to resume the thread if it's currently stopped
 677     bool shouldResume = false;
 678
 679     // as Delete() (which calls us) is always safe to call we need to consider
 680     // all possible states
 681     {
 682         wxCriticalSectionLocker lock(cs);
 683
 684         if ( m_state == STATE_NEW )
 685         {
 686             if ( shouldDelete )
 687             {
 688                 // WinThreadStart() will see it and terminate immediately, no
 689                 // need to cancel the thread -- but we still need to resume it
 690                 // to let it run
 691                 m_state = STATE_EXITED;
 692
 693                 // we must call Resume() as the thread hasn't been initially
 694                 // resumed yet (and as Resume() it knows about STATE_EXITED
 695                 // special case, it won't touch it and WinThreadStart() will
 696                 // just exit immediately)
 697                 shouldResume = true;
 698                 shouldDelete = false;
 699             }
 700             //else: shouldResume is correctly set to false here, wait until
 701             //      someone else runs the thread and it finishes
 702         }
 703         else // running, paused, cancelled or even exited
 704         {
 705             shouldResume = m_state == STATE_PAUSED;
 706         }
 707     }
 708
 709     // resume the thread if it is paused
 710     if ( shouldResume )
 711         Resume();
 712
 713     // ask the thread to terminate
 714     if ( shouldDelete )
 715     {
 716         wxCriticalSectionLocker lock(cs);
 717
 718         Cancel();
 719     }
 720
 721
 722     // now wait for thread to finish
 723     if ( wxThread::IsMain() )
 724     {
 725         // set flag for wxIsWaitingForThread()
 726         gs_waitingForThread = true;
 727     }
 728
 729     // we can't just wait for the thread to terminate because it might be
 730     // calling some GUI functions and so it will never terminate before we
 731     // process the Windows messages that result from these functions
 732     // (note that even in console applications we might have to process
 733     // messages if we use wxExecute() or timers or ...)
 734     DWORD result wxDUMMY_INITIALIZE(0);
 735     do
 736     {
 737         if ( wxThread::IsMain() )
 738         {
 739             // give the thread we're waiting for chance to do the GUI call
 740             // it might be in
 741             if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 742             {
 743                 wxMutexGuiLeave();
 744             }
 745         }
 746
 747 #if !defined(QS_ALLPOSTMESSAGE)
 748 #define QS_ALLPOSTMESSAGE 0
 749 #endif
 750
 751         result = ::MsgWaitForMultipleObjects
 752                  (
 753                    1,              // number of objects to wait for
 754                    &m_hThread,     // the objects
 755                    false,          // don't wait for all objects
 756                    INFINITE,       // no timeout
 757                    QS_ALLINPUT|QS_ALLPOSTMESSAGE   // return as soon as there are any events
 758                  );
 759
 760         switch ( result )
 761         {
 762             case 0xFFFFFFFF:
 763                 // error
 764                 wxLogSysError(_("Can not wait for thread termination"));
 765                 Kill();
 766                 return wxTHREAD_KILLED;
 767
 768             case WAIT_OBJECT_0:
 769                 // thread we're waiting for terminated
 770                 break;
 771
 772             case WAIT_OBJECT_0 + 1:
 773                 // new message arrived, process it -- but only if we're the
 774                 // main thread as we don't support processing messages in
 775                 // the other ones
 776                 //
 777                 // NB: we still must include QS_ALLINPUT even when waiting
 778                 //     in a secondary thread because if it had created some
 779                 //     window somehow (possible not even using wxWidgets)
 780                 //     the system might dead lock then
 781                 if ( wxThread::IsMain() )
 782                 {
 783                     wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits()
 784                                                    : NULL;
 785
 786                     if ( traits && !traits->DoMessageFromThreadWait() )
 787                     {
 788                         // WM_QUIT received: kill the thread
 789                         Kill();
 790
 791                         return wxTHREAD_KILLED;
 792                     }
 793                 }
 794                 break;
 795
 796             default:
 797                 wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
 798         }
 799     } while ( result != WAIT_OBJECT_0 );
 800
 801     if ( wxThread::IsMain() )
 802     {
 803         gs_waitingForThread = false;
 804     }
 805
 806
 807     // although the thread might be already in the EXITED state it might not
 808     // have terminated yet and so we are not sure that it has actually
 809     // terminated if the "if" above hadn't been taken
 810     for ( ;; )
 811     {
 812         if ( !::GetExitCodeThread(m_hThread, (LPDWORD)&rc) )
 813         {
 814             wxLogLastError(wxT("GetExitCodeThread"));
 815
 816             rc = (wxThread::ExitCode)-1;
 817
 818             break;
 819         }
 820
 821         if ( (DWORD)rc != STILL_ACTIVE )
 822             break;
 823
 824         // give the other thread some time to terminate, otherwise we may be
 825         // starving it
 826         ::Sleep(1);
 827     }
 828
 829     if ( pRc )
 830         *pRc = rc;
 831
 832     // we don't need the thread handle any more in any case
 833     Free();
 834
 835
 836     return rc == (wxThread::ExitCode)-1 ? wxTHREAD_MISC_ERROR
 837                                         : wxTHREAD_NO_ERROR;
 838 }
 839
 840 bool wxThreadInternal::Suspend()
 841 {
 842     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 843     if ( nSuspendCount == (DWORD)-1 )
 844     {
 845         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 846
 847         return false;
 848     }
 849
 850     m_state = STATE_PAUSED;
 851
 852     return true;
 853 }
 854
 855 bool wxThreadInternal::Resume()
 856 {
 857     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 858     if ( nSuspendCount == (DWORD)-1 )
 859     {
 860         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 861
 862         return false;
 863     }
 864
 865     // don't change the state from STATE_EXITED because it's special and means
 866     // we are going to terminate without running any user code - if we did it,
 867     // the code in WaitForTerminate() wouldn't work
 868     if ( m_state != STATE_EXITED )
 869     {
 870         m_state = STATE_RUNNING;
 871     }
 872
 873     return true;
 874 }
 875
 876 // static functions
 877 // ----------------
 878
 879 wxThread *wxThread::This()
 880 {
 881     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 882
 883     // be careful, 0 may be a valid return value as well
 884     if ( !thread && (::GetLastError() != NO_ERROR) )
 885     {
 886         wxLogSysError(_("Couldn't get the current thread pointer"));
 887
 888         // return NULL...
 889     }
 890
 891     return thread;
 892 }
 893
 894 bool wxThread::IsMain()
 895 {
 896     return ::GetCurrentThreadId() == gs_idMainThread || gs_idMainThread == 0;
 897 }
 898
 899 void wxThread::Yield()
 900 {
 901     // 0 argument to Sleep() is special and means to just give away the rest of
 902     // our timeslice
 903     ::Sleep(0);
 904 }
 905
 906 void wxThread::Sleep(unsigned long milliseconds)
 907 {
 908     ::Sleep(milliseconds);
 909 }
 910
 911 int wxThread::GetCPUCount()
 912 {
 913     SYSTEM_INFO si;
 914     GetSystemInfo(&si);
 915
 916     return si.dwNumberOfProcessors;
 917 }
 918
 919 unsigned long wxThread::GetCurrentId()
 920 {
 921     return (unsigned long)::GetCurrentThreadId();
 922 }
 923
 924 bool wxThread::SetConcurrency(size_t WXUNUSED_IN_WINCE(level))
 925 {
 926 #ifdef __WXWINCE__
 927     return false;
 928 #else
 929     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 930
 931     // ok only for the default one
 932     if ( level == 0 )
 933         return 0;
 934
 935     // get system affinity mask first
 936     HANDLE hProcess = ::GetCurrentProcess();
 937     DWORD_PTR dwProcMask, dwSysMask;
 938     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 939     {
 940         wxLogLastError(_T("GetProcessAffinityMask"));
 941
 942         return false;
 943     }
 944
 945     // how many CPUs have we got?
 946     if ( dwSysMask == 1 )
 947     {
 948         // don't bother with all this complicated stuff - on a single
 949         // processor system it doesn't make much sense anyhow
 950         return level == 1;
 951     }
 952
 953     // calculate the process mask: it's a bit vector with one bit per
 954     // processor; we want to schedule the process to run on first level
 955     // CPUs
 956     DWORD bit = 1;
 957     while ( bit )
 958     {
 959         if ( dwSysMask & bit )
 960         {
 961             // ok, we can set this bit
 962             dwProcMask |= bit;
 963
 964             // another process added
 965             if ( --level == 0 )
 966             {
 967                 // and that's enough
 968                 break;
 969             }
 970         }
 971
 972         // next bit
 973         bit <<= 1;
 974     }
 975
 976     // could we set all bits?
 977     if ( level != 0 )
 978     {
 979         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 980
 981         return false;
 982     }
 983
 984     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 985     // exist in Win9x, use RT binding instead
 986
 987     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
 988
 989     // can use static var because we're always in the main thread here
 990     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
 991
 992     if ( !pfnSetProcessAffinityMask )
 993     {
 994         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
 995         if ( hModKernel )
 996         {
 997             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
 998                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
 999         }
1000
1001         // we've discovered a MT version of Win9x!
1002         wxASSERT_MSG( pfnSetProcessAffinityMask,
1003                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
1004     }
1005
1006     if ( !pfnSetProcessAffinityMask )
1007     {
1008         // msg given above - do it only once
1009         return false;
1010     }
1011
1012     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
1013     {
1014         wxLogLastError(_T("SetProcessAffinityMask"));
1015
1016         return false;
1017     }
1018
1019     return true;
1020 #endif // __WXWINCE__/!__WXWINCE__
1021 }
1022
1023 // ctor and dtor
1024 // -------------
1025
1026 wxThread::wxThread(wxThreadKind kind)
1027 {
1028     m_internal = new wxThreadInternal(this);
1029
1030     m_isDetached = kind == wxTHREAD_DETACHED;
1031 }
1032
1033 wxThread::~wxThread()
1034 {
1035     delete m_internal;
1036 }
1037
1038 // create/start thread
1039 // -------------------
1040
1041 wxThreadError wxThread::Create(unsigned int stackSize)
1042 {
1043     wxCriticalSectionLocker lock(m_critsect);
1044
1045     if ( !m_internal->Create(this, stackSize) )
1046         return wxTHREAD_NO_RESOURCE;
1047
1048     return wxTHREAD_NO_ERROR;
1049 }
1050
1051 wxThreadError wxThread::Run()
1052 {
1053     wxCriticalSectionLocker lock(m_critsect);
1054
1055     if ( m_internal->GetState() != STATE_NEW )
1056     {
1057         // actually, it may be almost any state at all, not only STATE_RUNNING
1058         return wxTHREAD_RUNNING;
1059     }
1060
1061     // the thread has just been created and is still suspended - let it run
1062     return Resume();
1063 }
1064
1065 // suspend/resume thread
1066 // ---------------------
1067
1068 wxThreadError wxThread::Pause()
1069 {
1070     wxCriticalSectionLocker lock(m_critsect);
1071
1072     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1073 }
1074
1075 wxThreadError wxThread::Resume()
1076 {
1077     wxCriticalSectionLocker lock(m_critsect);
1078
1079     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1080 }
1081
1082 // stopping thread
1083 // ---------------
1084
1085 wxThread::ExitCode wxThread::Wait()
1086 {
1087     // although under Windows we can wait for any thread, it's an error to
1088     // wait for a detached one in wxWin API
1089     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
1090                  _T("wxThread::Wait(): can't wait for detached thread") );
1091
1092     ExitCode rc = (ExitCode)-1;
1093
1094     (void)m_internal->WaitForTerminate(m_critsect, &rc);
1095
1096     return rc;
1097 }
1098
1099 wxThreadError wxThread::Delete(ExitCode *pRc)
1100 {
1101     return m_internal->WaitForTerminate(m_critsect, pRc, this);
1102 }
1103
1104 wxThreadError wxThread::Kill()
1105 {
1106     if ( !IsRunning() )
1107         return wxTHREAD_NOT_RUNNING;
1108
1109     wxThreadError rc = m_internal->Kill();
1110
1111     if ( IsDetached() )
1112     {
1113         delete this;
1114     }
1115     else // joinable
1116     {
1117         // update the status of the joinable thread
1118         wxCriticalSectionLocker lock(m_critsect);
1119         m_internal->SetState(STATE_EXITED);
1120     }
1121
1122     return rc;
1123 }
1124
1125 void wxThread::Exit(ExitCode status)
1126 {
1127     m_internal->Free();
1128
1129     if ( IsDetached() )
1130     {
1131         delete this;
1132     }
1133     else // joinable
1134     {
1135         // update the status of the joinable thread
1136         wxCriticalSectionLocker lock(m_critsect);
1137         m_internal->SetState(STATE_EXITED);
1138     }
1139
1140 #ifdef wxUSE_BEGIN_THREAD
1141     _endthreadex((unsigned)status);
1142 #else // !VC++
1143     ::ExitThread((DWORD)status);
1144 #endif // VC++/!VC++
1145
1146     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1147 }
1148
1149 // priority setting
1150 // ----------------
1151
1152 void wxThread::SetPriority(unsigned int prio)
1153 {
1154     wxCriticalSectionLocker lock(m_critsect);
1155
1156     m_internal->SetPriority(prio);
1157 }
1158
1159 unsigned int wxThread::GetPriority() const
1160 {
1161     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1162
1163     return m_internal->GetPriority();
1164 }
1165
1166 unsigned long wxThread::GetId() const
1167 {
1168     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1169
1170     return (unsigned long)m_internal->GetId();
1171 }
1172
1173 bool wxThread::IsRunning() const
1174 {
1175     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1176
1177     return m_internal->GetState() == STATE_RUNNING;
1178 }
1179
1180 bool wxThread::IsAlive() const
1181 {
1182     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1183
1184     return (m_internal->GetState() == STATE_RUNNING) ||
1185            (m_internal->GetState() == STATE_PAUSED);
1186 }
1187
1188 bool wxThread::IsPaused() const
1189 {
1190     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1191
1192     return m_internal->GetState() == STATE_PAUSED;
1193 }
1194
1195 bool wxThread::TestDestroy()
1196 {
1197     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1198
1199     return m_internal->GetState() == STATE_CANCELED;
1200 }
1201
1202 // ----------------------------------------------------------------------------
1203 // Automatic initialization for thread module
1204 // ----------------------------------------------------------------------------
1205
1206 class wxThreadModule : public wxModule
1207 {
1208 public:
1209     virtual bool OnInit();
1210     virtual void OnExit();
1211
1212 private:
1213     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1214 };
1215
1216 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1217
1218 bool wxThreadModule::OnInit()
1219 {
1220     // allocate TLS index for storing the pointer to the current thread
1221     gs_tlsThisThread = ::TlsAlloc();
1222     if ( gs_tlsThisThread == 0xFFFFFFFF )
1223     {
1224         // in normal circumstances it will only happen if all other
1225         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1226         // words, this should never happen
1227         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1228
1229         return false;
1230     }
1231
1232     // main thread doesn't have associated wxThread object, so store 0 in the
1233     // TLS instead
1234     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1235     {
1236         ::TlsFree(gs_tlsThisThread);
1237         gs_tlsThisThread = 0xFFFFFFFF;
1238
1239         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1240
1241         return false;
1242     }
1243
1244     gs_critsectWaitingForGui = new wxCriticalSection();
1245
1246     gs_critsectGui = new wxCriticalSection();
1247     gs_critsectGui->Enter();
1248
1249     gs_critsectThreadDelete = new wxCriticalSection;
1250
1251     // no error return for GetCurrentThreadId()
1252     gs_idMainThread = ::GetCurrentThreadId();
1253
1254     return true;
1255 }
1256
1257 void wxThreadModule::OnExit()
1258 {
1259     if ( !::TlsFree(gs_tlsThisThread) )
1260     {
1261         wxLogLastError(wxT("TlsFree failed."));
1262     }
1263
1264     delete gs_critsectThreadDelete;
1265     gs_critsectThreadDelete = NULL;
1266
1267     if ( gs_critsectGui )
1268     {
1269         gs_critsectGui->Leave();
1270         delete gs_critsectGui;
1271         gs_critsectGui = NULL;
1272     }
1273
1274     delete gs_critsectWaitingForGui;
1275     gs_critsectWaitingForGui = NULL;
1276 }
1277
1278 // ----------------------------------------------------------------------------
1279 // under Windows, these functions are implemented using a critical section and
1280 // not a mutex, so the names are a bit confusing
1281 // ----------------------------------------------------------------------------
1282
1283 void WXDLLIMPEXP_BASE wxMutexGuiEnter()
1284 {
1285     // this would dead lock everything...
1286     wxASSERT_MSG( !wxThread::IsMain(),
1287                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1288
1289     // the order in which we enter the critical sections here is crucial!!
1290
1291     // set the flag telling to the main thread that we want to do some GUI
1292     {
1293         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1294
1295         gs_nWaitingForGui++;
1296     }
1297
1298     wxWakeUpMainThread();
1299
1300     // now we may block here because the main thread will soon let us in
1301     // (during the next iteration of OnIdle())
1302     gs_critsectGui->Enter();
1303 }
1304
1305 void WXDLLIMPEXP_BASE wxMutexGuiLeave()
1306 {
1307     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1308
1309     if ( wxThread::IsMain() )
1310     {
1311         gs_bGuiOwnedByMainThread = false;
1312     }
1313     else
1314     {
1315         // decrement the number of threads waiting for GUI access now
1316         wxASSERT_MSG( gs_nWaitingForGui > 0,
1317                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1318
1319         gs_nWaitingForGui--;
1320
1321         wxWakeUpMainThread();
1322     }
1323
1324     gs_critsectGui->Leave();
1325 }
1326
1327 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1328 {
1329     wxASSERT_MSG( wxThread::IsMain(),
1330                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1331
1332     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1333
1334     if ( gs_nWaitingForGui == 0 )
1335     {
1336         // no threads are waiting for GUI - so we may acquire the lock without
1337         // any danger (but only if we don't already have it)
1338         if ( !wxGuiOwnedByMainThread() )
1339         {
1340             gs_critsectGui->Enter();
1341
1342             gs_bGuiOwnedByMainThread = true;
1343         }
1344         //else: already have it, nothing to do
1345     }
1346     else
1347     {
1348         // some threads are waiting, release the GUI lock if we have it
1349         if ( wxGuiOwnedByMainThread() )
1350         {
1351             wxMutexGuiLeave();
1352         }
1353         //else: some other worker thread is doing GUI
1354     }
1355 }
1356
1357 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1358 {
1359     return gs_bGuiOwnedByMainThread;
1360 }
1361
1362 // wake up the main thread if it's in ::GetMessage()
1363 void WXDLLIMPEXP_BASE wxWakeUpMainThread()
1364 {
1365     // sending any message would do - hopefully WM_NULL is harmless enough
1366     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1367     {
1368         // should never happen
1369         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1370     }
1371 }
1372
1373 bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
1374 {
1375     return gs_waitingForThread;
1376 }
1377
1378 // ----------------------------------------------------------------------------
1379 // include common implementation code
1380 // ----------------------------------------------------------------------------
1381
1382 #include "wx/thrimpl.cpp"
1383
1384 #endif // wxUSE_THREADS