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 #ifndef WX_PRECOMP
  25     #include "wx/intl.h"
  26     #include "wx/app.h"
  27 #endif
  28
  29 #if wxUSE_THREADS
  30
  31 #include "wx/apptrait.h"
  32 #include "wx/scopeguard.h"
  33
  34 #include "wx/msw/private.h"
  35 #include "wx/msw/missing.h"
  36 #include "wx/msw/seh.h"
  37
  38 #include "wx/except.h"
  39 #include "wx/module.h"
  40 #include "wx/thread.h"
  41
  42 // must have this symbol defined to get _beginthread/_endthread declarations
  43 #ifndef _MT
  44     #define _MT
  45 #endif
  46
  47 #if defined(__BORLANDC__)
  48     #if !defined(__MT__)
  49         // I can't set -tWM in the IDE (anyone?) so have to do this
  50         #define __MT__
  51     #endif
  52
  53     #if !defined(__MFC_COMPAT__)
  54         // Needed to know about _beginthreadex etc..
  55         #define __MFC_COMPAT__
  56     #endif
  57 #endif // BC++
  58
  59 // define wxUSE_BEGIN_THREAD if the compiler has _beginthreadex() function
  60 // which should be used instead of Win32 ::CreateThread() if possible
  61 #if defined(__VISUALC__) || \
  62     (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \
  63     (defined(__GNUG__) && defined(__MSVCRT__)) || \
  64     defined(__WATCOMC__) || defined(__MWERKS__)
  65
  66 #ifndef __WXWINCE__
  67     #undef wxUSE_BEGIN_THREAD
  68     #define wxUSE_BEGIN_THREAD
  69 #endif
  70
  71 #endif
  72
  73 #ifdef wxUSE_BEGIN_THREAD
  74     // this is where _beginthreadex() is declared
  75     #include <process.h>
  76
  77     // the return type of the thread function entry point
  78     typedef unsigned THREAD_RETVAL;
  79
  80     // the calling convention of the thread function entry point
  81     #define THREAD_CALLCONV __stdcall
  82 #else
  83     // the settings for CreateThread()
  84     typedef DWORD THREAD_RETVAL;
  85     #define THREAD_CALLCONV WINAPI
  86 #endif
  87
  88 // ----------------------------------------------------------------------------
  89 // constants
  90 // ----------------------------------------------------------------------------
  91
  92 // the possible states of the thread ("=>" shows all possible transitions from
  93 // this state)
  94 enum wxThreadState
  95 {
  96     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  97     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  98     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
  99     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
 100     STATE_EXITED        // thread is terminating
 101 };
 102
 103 // ----------------------------------------------------------------------------
 104 // this module globals
 105 // ----------------------------------------------------------------------------
 106
 107 // TLS index of the slot where we store the pointer to the current thread
 108 static DWORD gs_tlsThisThread = 0xFFFFFFFF;
 109
 110 // id of the main thread - the one which can call GUI functions without first
 111 // calling wxMutexGuiEnter()
 112 static DWORD gs_idMainThread = 0;
 113
 114 // if it's false, some secondary thread is holding the GUI lock
 115 static bool gs_bGuiOwnedByMainThread = true;
 116
 117 // critical section which controls access to all GUI functions: any secondary
 118 // thread (i.e. except the main one) must enter this crit section before doing
 119 // any GUI calls
 120 static wxCriticalSection *gs_critsectGui = NULL;
 121
 122 // critical section which protects gs_nWaitingForGui variable
 123 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
 124
 125 // critical section which serializes WinThreadStart() and WaitForTerminate()
 126 // (this is a potential bottleneck, we use a single crit sect for all threads
 127 // in the system, but normally time spent inside it should be quite short)
 128 static wxCriticalSection *gs_critsectThreadDelete = NULL;
 129
 130 // number of threads waiting for GUI in wxMutexGuiEnter()
 131 static size_t gs_nWaitingForGui = 0;
 132
 133 // are we waiting for a thread termination?
 134 static bool gs_waitingForThread = false;
 135
 136 // ============================================================================
 137 // Windows implementation of thread and related classes
 138 // ============================================================================
 139
 140 // ----------------------------------------------------------------------------
 141 // wxCriticalSection
 142 // ----------------------------------------------------------------------------
 143
 144 wxCriticalSection::wxCriticalSection()
 145 {
 146     wxCOMPILE_TIME_ASSERT( sizeof(CRITICAL_SECTION) <= sizeof(wxCritSectBuffer),
 147                            wxCriticalSectionBufferTooSmall );
 148
 149     ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
 150 }
 151
 152 wxCriticalSection::~wxCriticalSection()
 153 {
 154     ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
 155 }
 156
 157 void wxCriticalSection::Enter()
 158 {
 159     ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
 160 }
 161
 162 void wxCriticalSection::Leave()
 163 {
 164     ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
 165 }
 166
 167 // ----------------------------------------------------------------------------
 168 // wxMutex
 169 // ----------------------------------------------------------------------------
 170
 171 class wxMutexInternal
 172 {
 173 public:
 174     wxMutexInternal(wxMutexType mutexType);
 175     ~wxMutexInternal();
 176
 177     bool IsOk() const { return m_mutex != NULL; }
 178
 179     wxMutexError Lock() { return LockTimeout(INFINITE); }
 180     wxMutexError TryLock() { return LockTimeout(0); }
 181     wxMutexError Unlock();
 182
 183 private:
 184     wxMutexError LockTimeout(DWORD milliseconds);
 185
 186     HANDLE m_mutex;
 187
 188     DECLARE_NO_COPY_CLASS(wxMutexInternal)
 189 };
 190
 191 // all mutexes are recursive under Win32 so we don't use mutexType
 192 wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
 193 {
 194     // create a nameless (hence intra process and always private) mutex
 195     m_mutex = ::CreateMutex
 196                 (
 197                     NULL,       // default secutiry attributes
 198                     false,      // not initially locked
 199                     NULL        // no name
 200                 );
 201
 202     if ( !m_mutex )
 203     {
 204         wxLogLastError(_T("CreateMutex()"));
 205     }
 206 }
 207
 208 wxMutexInternal::~wxMutexInternal()
 209 {
 210     if ( m_mutex )
 211     {
 212         if ( !::CloseHandle(m_mutex) )
 213         {
 214             wxLogLastError(_T("CloseHandle(mutex)"));
 215         }
 216     }
 217 }
 218
 219 wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
 220 {
 221     DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
 222     if ( rc == WAIT_ABANDONED )
 223     {
 224         // the previous caller died without releasing the mutex, but now we can
 225         // really lock it
 226         wxLogDebug(_T("WaitForSingleObject() returned WAIT_ABANDONED"));
 227
 228         // use 0 timeout, normally we should always get it
 229         rc = ::WaitForSingleObject(m_mutex, 0);
 230     }
 231
 232     switch ( rc )
 233     {
 234         case WAIT_OBJECT_0:
 235             // ok
 236             break;
 237
 238         case WAIT_TIMEOUT:
 239             return wxMUTEX_BUSY;
 240
 241         case WAIT_ABANDONED:        // checked for above
 242         default:
 243             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 244             // fall through
 245
 246         case WAIT_FAILED:
 247             wxLogLastError(_T("WaitForSingleObject(mutex)"));
 248             return wxMUTEX_MISC_ERROR;
 249     }
 250
 251     return wxMUTEX_NO_ERROR;
 252 }
 253
 254 wxMutexError wxMutexInternal::Unlock()
 255 {
 256     if ( !::ReleaseMutex(m_mutex) )
 257     {
 258         wxLogLastError(_T("ReleaseMutex()"));
 259
 260         return wxMUTEX_MISC_ERROR;
 261     }
 262
 263     return wxMUTEX_NO_ERROR;
 264 }
 265
 266 // --------------------------------------------------------------------------
 267 // wxSemaphore
 268 // --------------------------------------------------------------------------
 269
 270 // a trivial wrapper around Win32 semaphore
 271 class wxSemaphoreInternal
 272 {
 273 public:
 274     wxSemaphoreInternal(int initialcount, int maxcount);
 275     ~wxSemaphoreInternal();
 276
 277     bool IsOk() const { return m_semaphore != NULL; }
 278
 279     wxSemaError Wait() { return WaitTimeout(INFINITE); }
 280
 281     wxSemaError TryWait()
 282     {
 283         wxSemaError rc = WaitTimeout(0);
 284         if ( rc == wxSEMA_TIMEOUT )
 285             rc = wxSEMA_BUSY;
 286
 287         return rc;
 288     }
 289
 290     wxSemaError WaitTimeout(unsigned long milliseconds);
 291
 292     wxSemaError Post();
 293
 294 private:
 295     HANDLE m_semaphore;
 296
 297     DECLARE_NO_COPY_CLASS(wxSemaphoreInternal)
 298 };
 299
 300 wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
 301 {
 302 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
 303     if ( maxcount == 0 )
 304     {
 305         // make it practically infinite
 306         maxcount = INT_MAX;
 307     }
 308
 309     m_semaphore = ::CreateSemaphore
 310                     (
 311                         NULL,           // default security attributes
 312                         initialcount,
 313                         maxcount,
 314                         NULL            // no name
 315                     );
 316 #endif
 317     if ( !m_semaphore )
 318     {
 319         wxLogLastError(_T("CreateSemaphore()"));
 320     }
 321 }
 322
 323 wxSemaphoreInternal::~wxSemaphoreInternal()
 324 {
 325     if ( m_semaphore )
 326     {
 327         if ( !::CloseHandle(m_semaphore) )
 328         {
 329             wxLogLastError(_T("CloseHandle(semaphore)"));
 330         }
 331     }
 332 }
 333
 334 wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long milliseconds)
 335 {
 336     DWORD rc = ::WaitForSingleObject( m_semaphore, milliseconds );
 337
 338     switch ( rc )
 339     {
 340         case WAIT_OBJECT_0:
 341            return wxSEMA_NO_ERROR;
 342
 343         case WAIT_TIMEOUT:
 344            return wxSEMA_TIMEOUT;
 345
 346         default:
 347             wxLogLastError(_T("WaitForSingleObject(semaphore)"));
 348     }
 349
 350     return wxSEMA_MISC_ERROR;
 351 }
 352
 353 wxSemaError wxSemaphoreInternal::Post()
 354 {
 355 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
 356     if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
 357 #endif
 358     {
 359         wxLogLastError(_T("ReleaseSemaphore"));
 360
 361         return wxSEMA_MISC_ERROR;
 362     }
 363
 364     return wxSEMA_NO_ERROR;
 365 }
 366
 367 // ----------------------------------------------------------------------------
 368 // wxThread implementation
 369 // ----------------------------------------------------------------------------
 370
 371 // wxThreadInternal class
 372 // ----------------------
 373
 374 class wxThreadInternal
 375 {
 376 public:
 377     wxThreadInternal(wxThread *thread)
 378     {
 379         m_thread = thread;
 380         m_hThread = 0;
 381         m_state = STATE_NEW;
 382         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 383         m_nRef = 1;
 384     }
 385
 386     ~wxThreadInternal()
 387     {
 388         Free();
 389     }
 390
 391     void Free()
 392     {
 393         if ( m_hThread )
 394         {
 395             if ( !::CloseHandle(m_hThread) )
 396             {
 397                 wxLogLastError(wxT("CloseHandle(thread)"));
 398             }
 399
 400             m_hThread = 0;
 401         }
 402     }
 403
 404     // create a new (suspended) thread (for the given thread object)
 405     bool Create(wxThread *thread, unsigned int stackSize);
 406
 407     // wait for the thread to terminate, either by itself, or by asking it
 408     // (politely, this is not Kill()!) to do it
 409     wxThreadError WaitForTerminate(wxCriticalSection& cs,
 410                                    wxThread::ExitCode *pRc,
 411                                    wxThread *threadToDelete = NULL);
 412
 413     // kill the thread unconditionally
 414     wxThreadError Kill();
 415
 416     // suspend/resume/terminate
 417     bool Suspend();
 418     bool Resume();
 419     void Cancel() { m_state = STATE_CANCELED; }
 420
 421     // thread state
 422     void SetState(wxThreadState state) { m_state = state; }
 423     wxThreadState GetState() const { return m_state; }
 424
 425     // thread priority
 426     void SetPriority(unsigned int priority);
 427     unsigned int GetPriority() const { return m_priority; }
 428
 429     // thread handle and id
 430     HANDLE GetHandle() const { return m_hThread; }
 431     DWORD  GetId() const { return m_tid; }
 432
 433     // the thread function forwarding to DoThreadStart
 434     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 435
 436     // really start the thread (if it's not already dead)
 437     static THREAD_RETVAL DoThreadStart(wxThread *thread);
 438
 439     void KeepAlive()
 440     {
 441         if ( m_thread->IsDetached() )
 442             ::InterlockedIncrement(&m_nRef);
 443     }
 444
 445     void LetDie()
 446     {
 447         if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
 448             delete m_thread;
 449     }
 450
 451 private:
 452     // the thread we're associated with
 453     wxThread *m_thread;
 454
 455     HANDLE        m_hThread;    // handle of the thread
 456     wxThreadState m_state;      // state, see wxThreadState enum
 457     unsigned int  m_priority;   // thread priority in "wx" units
 458     DWORD         m_tid;        // thread id
 459
 460     // number of threads which need this thread to remain alive, when the count
 461     // reaches 0 we kill the owning wxThread -- and die ourselves with it
 462     LONG m_nRef;
 463
 464     DECLARE_NO_COPY_CLASS(wxThreadInternal)
 465 };
 466
 467 // small class which keeps a thread alive during its lifetime
 468 class wxThreadKeepAlive
 469 {
 470 public:
 471     wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
 472         { m_thrImpl.KeepAlive(); }
 473     ~wxThreadKeepAlive()
 474         { m_thrImpl.LetDie(); }
 475
 476 private:
 477     wxThreadInternal& m_thrImpl;
 478 };
 479
 480 THREAD_RETVAL wxThreadInternal::DoThreadStart(wxThread *thread)
 481 {
 482     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 483
 484     wxTRY
 485     {
 486         wxON_BLOCK_EXIT_OBJ0(*thread, wxThread::OnExit);
 487
 488         // store the thread object in the TLS
 489         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 490         {
 491             wxLogSysError(_("Can not start thread: error writing TLS."));
 492
 493             return (THREAD_RETVAL)-1;
 494         }
 495
 496         rc = (THREAD_RETVAL)thread->Entry();
 497     }
 498     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 499
 500     return rc;
 501 }
 502
 503 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 504 {
 505     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 506
 507     wxThread * const thread = (wxThread *)param;
 508
 509     // each thread has its own SEH translator so install our own a.s.a.p.
 510     DisableAutomaticSETranslator();
 511
 512     // first of all, check whether we hadn't been cancelled already and don't
 513     // start the user code at all then
 514     const bool hasExited = thread->m_internal->GetState() == STATE_EXITED;
 515
 516     if ( !hasExited )
 517     {
 518         wxSEH_TRY
 519         {
 520             rc = DoThreadStart(thread);
 521         }
 522         wxSEH_HANDLE((THREAD_RETVAL)-1)
 523     }
 524
 525     // save IsDetached because thread object can be deleted by joinable
 526     // threads after state is changed to STATE_EXITED.
 527     const bool isDetached = thread->IsDetached();
 528     if ( !hasExited )
 529     {
 530         // enter m_critsect before changing the thread state
 531         //
 532         // NB: can't use wxCriticalSectionLocker here as we use SEH and it's
 533         //     incompatible with C++ object dtors
 534         thread->m_critsect.Enter();
 535         thread->m_internal->SetState(STATE_EXITED);
 536         thread->m_critsect.Leave();
 537     }
 538
 539     // the thread may delete itself now if it wants, we don't need it any more
 540     if ( isDetached )
 541         thread->m_internal->LetDie();
 542
 543     return rc;
 544 }
 545
 546 void wxThreadInternal::SetPriority(unsigned int priority)
 547 {
 548     m_priority = priority;
 549
 550     // translate wxWidgets priority to the Windows one
 551     int win_priority;
 552     if (m_priority <= 20)
 553         win_priority = THREAD_PRIORITY_LOWEST;
 554     else if (m_priority <= 40)
 555         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 556     else if (m_priority <= 60)
 557         win_priority = THREAD_PRIORITY_NORMAL;
 558     else if (m_priority <= 80)
 559         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 560     else if (m_priority <= 100)
 561         win_priority = THREAD_PRIORITY_HIGHEST;
 562     else
 563     {
 564         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 565         win_priority = THREAD_PRIORITY_NORMAL;
 566     }
 567
 568     if ( !::SetThreadPriority(m_hThread, win_priority) )
 569     {
 570         wxLogSysError(_("Can't set thread priority"));
 571     }
 572 }
 573
 574 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 575 {
 576     wxASSERT_MSG( m_state == STATE_NEW && !m_hThread,
 577                     _T("Create()ing thread twice?") );
 578
 579     // for compilers which have it, we should use C RTL function for thread
 580     // creation instead of Win32 API one because otherwise we will have memory
 581     // leaks if the thread uses C RTL (and most threads do)
 582 #ifdef wxUSE_BEGIN_THREAD
 583
 584     // Watcom is reported to not like 0 stack size (which means "use default"
 585     // for the other compilers and is also the default value for stackSize)
 586 #ifdef __WATCOMC__
 587     if ( !stackSize )
 588         stackSize = 10240;
 589 #endif // __WATCOMC__
 590
 591     m_hThread = (HANDLE)_beginthreadex
 592                         (
 593                           NULL,                             // default security
 594                           stackSize,
 595                           wxThreadInternal::WinThreadStart, // entry point
 596                           thread,
 597                           CREATE_SUSPENDED,
 598                           (unsigned int *)&m_tid
 599                         );
 600 #else // compiler doesn't have _beginthreadex
 601     m_hThread = ::CreateThread
 602                   (
 603                     NULL,                               // default security
 604                     stackSize,                          // stack size
 605                     wxThreadInternal::WinThreadStart,   // thread entry point
 606                     (LPVOID)thread,                     // parameter
 607                     CREATE_SUSPENDED,                   // flags
 608                     &m_tid                              // [out] thread id
 609                   );
 610 #endif // _beginthreadex/CreateThread
 611
 612     if ( m_hThread == NULL )
 613     {
 614         wxLogSysError(_("Can't create thread"));
 615
 616         return false;
 617     }
 618
 619     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 620     {
 621         SetPriority(m_priority);
 622     }
 623
 624     return true;
 625 }
 626
 627 wxThreadError wxThreadInternal::Kill()
 628 {
 629     if ( !::TerminateThread(m_hThread, (DWORD)-1) )
 630     {
 631         wxLogSysError(_("Couldn't terminate thread"));
 632
 633         return wxTHREAD_MISC_ERROR;
 634     }
 635
 636     Free();
 637
 638     return wxTHREAD_NO_ERROR;
 639 }
 640
 641 wxThreadError
 642 wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
 643                                    wxThread::ExitCode *pRc,
 644                                    wxThread *threadToDelete)
 645 {
 646     // prevent the thread C++ object from disappearing as long as we are using
 647     // it here
 648     wxThreadKeepAlive keepAlive(*this);
 649
 650
 651     // we may either wait passively for the thread to terminate (when called
 652     // from Wait()) or ask it to terminate (when called from Delete())
 653     bool shouldDelete = threadToDelete != NULL;
 654
 655     wxThread::ExitCode rc = 0;
 656
 657     // we might need to resume the thread if it's currently stopped
 658     bool shouldResume = false;
 659
 660     // as Delete() (which calls us) is always safe to call we need to consider
 661     // all possible states
 662     {
 663         wxCriticalSectionLocker lock(cs);
 664
 665         if ( m_state == STATE_NEW )
 666         {
 667             if ( shouldDelete )
 668             {
 669                 // WinThreadStart() will see it and terminate immediately, no
 670                 // need to cancel the thread -- but we still need to resume it
 671                 // to let it run
 672                 m_state = STATE_EXITED;
 673
 674                 // we must call Resume() as the thread hasn't been initially
 675                 // resumed yet (and as Resume() it knows about STATE_EXITED
 676                 // special case, it won't touch it and WinThreadStart() will
 677                 // just exit immediately)
 678                 shouldResume = true;
 679                 shouldDelete = false;
 680             }
 681             //else: shouldResume is correctly set to false here, wait until
 682             //      someone else runs the thread and it finishes
 683         }
 684         else // running, paused, cancelled or even exited
 685         {
 686             shouldResume = m_state == STATE_PAUSED;
 687         }
 688     }
 689
 690     // resume the thread if it is paused
 691     if ( shouldResume )
 692         Resume();
 693
 694     // ask the thread to terminate
 695     if ( shouldDelete )
 696     {
 697         wxCriticalSectionLocker lock(cs);
 698
 699         Cancel();
 700     }
 701
 702
 703     // now wait for thread to finish
 704     if ( wxThread::IsMain() )
 705     {
 706         // set flag for wxIsWaitingForThread()
 707         gs_waitingForThread = true;
 708     }
 709
 710     // we can't just wait for the thread to terminate because it might be
 711     // calling some GUI functions and so it will never terminate before we
 712     // process the Windows messages that result from these functions
 713     // (note that even in console applications we might have to process
 714     // messages if we use wxExecute() or timers or ...)
 715     DWORD result wxDUMMY_INITIALIZE(0);
 716     do
 717     {
 718         if ( wxThread::IsMain() )
 719         {
 720             // give the thread we're waiting for chance to do the GUI call
 721             // it might be in
 722             if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 723             {
 724                 wxMutexGuiLeave();
 725             }
 726         }
 727
 728 #if !defined(QS_ALLPOSTMESSAGE)
 729 #define QS_ALLPOSTMESSAGE 0
 730 #endif
 731
 732         result = ::MsgWaitForMultipleObjects
 733                  (
 734                    1,              // number of objects to wait for
 735                    &m_hThread,     // the objects
 736                    false,          // don't wait for all objects
 737                    INFINITE,       // no timeout
 738                    QS_ALLINPUT|QS_ALLPOSTMESSAGE   // return as soon as there are any events
 739                  );
 740
 741         switch ( result )
 742         {
 743             case 0xFFFFFFFF:
 744                 // error
 745                 wxLogSysError(_("Can not wait for thread termination"));
 746                 Kill();
 747                 return wxTHREAD_KILLED;
 748
 749             case WAIT_OBJECT_0:
 750                 // thread we're waiting for terminated
 751                 break;
 752
 753             case WAIT_OBJECT_0 + 1:
 754                 // new message arrived, process it -- but only if we're the
 755                 // main thread as we don't support processing messages in
 756                 // the other ones
 757                 //
 758                 // NB: we still must include QS_ALLINPUT even when waiting
 759                 //     in a secondary thread because if it had created some
 760                 //     window somehow (possible not even using wxWidgets)
 761                 //     the system might dead lock then
 762                 if ( wxThread::IsMain() )
 763                 {
 764                     wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits()
 765                                                    : NULL;
 766
 767                     if ( traits && !traits->DoMessageFromThreadWait() )
 768                     {
 769                         // WM_QUIT received: kill the thread
 770                         Kill();
 771
 772                         return wxTHREAD_KILLED;
 773                     }
 774                 }
 775                 break;
 776
 777             default:
 778                 wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
 779         }
 780     } while ( result != WAIT_OBJECT_0 );
 781
 782     if ( wxThread::IsMain() )
 783     {
 784         gs_waitingForThread = false;
 785     }
 786
 787
 788     // although the thread might be already in the EXITED state it might not
 789     // have terminated yet and so we are not sure that it has actually
 790     // terminated if the "if" above hadn't been taken
 791     for ( ;; )
 792     {
 793         if ( !::GetExitCodeThread(m_hThread, (LPDWORD)&rc) )
 794         {
 795             wxLogLastError(wxT("GetExitCodeThread"));
 796
 797             rc = (wxThread::ExitCode)-1;
 798
 799             break;
 800         }
 801
 802         if ( (DWORD)rc != STILL_ACTIVE )
 803             break;
 804
 805         // give the other thread some time to terminate, otherwise we may be
 806         // starving it
 807         ::Sleep(1);
 808     }
 809
 810     if ( pRc )
 811         *pRc = rc;
 812
 813     // we don't need the thread handle any more in any case
 814     Free();
 815
 816
 817     return rc == (wxThread::ExitCode)-1 ? wxTHREAD_MISC_ERROR
 818                                         : wxTHREAD_NO_ERROR;
 819 }
 820
 821 bool wxThreadInternal::Suspend()
 822 {
 823     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 824     if ( nSuspendCount == (DWORD)-1 )
 825     {
 826         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 827
 828         return false;
 829     }
 830
 831     m_state = STATE_PAUSED;
 832
 833     return true;
 834 }
 835
 836 bool wxThreadInternal::Resume()
 837 {
 838     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 839     if ( nSuspendCount == (DWORD)-1 )
 840     {
 841         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 842
 843         return false;
 844     }
 845
 846     // don't change the state from STATE_EXITED because it's special and means
 847     // we are going to terminate without running any user code - if we did it,
 848     // the code in WaitForTerminate() wouldn't work
 849     if ( m_state != STATE_EXITED )
 850     {
 851         m_state = STATE_RUNNING;
 852     }
 853
 854     return true;
 855 }
 856
 857 // static functions
 858 // ----------------
 859
 860 wxThread *wxThread::This()
 861 {
 862     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 863
 864     // be careful, 0 may be a valid return value as well
 865     if ( !thread && (::GetLastError() != NO_ERROR) )
 866     {
 867         wxLogSysError(_("Couldn't get the current thread pointer"));
 868
 869         // return NULL...
 870     }
 871
 872     return thread;
 873 }
 874
 875 bool wxThread::IsMain()
 876 {
 877     return ::GetCurrentThreadId() == gs_idMainThread || gs_idMainThread == 0;
 878 }
 879
 880 void wxThread::Yield()
 881 {
 882     // 0 argument to Sleep() is special and means to just give away the rest of
 883     // our timeslice
 884     ::Sleep(0);
 885 }
 886
 887 void wxThread::Sleep(unsigned long milliseconds)
 888 {
 889     ::Sleep(milliseconds);
 890 }
 891
 892 int wxThread::GetCPUCount()
 893 {
 894     SYSTEM_INFO si;
 895     GetSystemInfo(&si);
 896
 897     return si.dwNumberOfProcessors;
 898 }
 899
 900 unsigned long wxThread::GetCurrentId()
 901 {
 902     return (unsigned long)::GetCurrentThreadId();
 903 }
 904
 905 bool wxThread::SetConcurrency(size_t WXUNUSED_IN_WINCE(level))
 906 {
 907 #ifdef __WXWINCE__
 908     return false;
 909 #else
 910     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 911
 912     // ok only for the default one
 913     if ( level == 0 )
 914         return 0;
 915
 916     // get system affinity mask first
 917     HANDLE hProcess = ::GetCurrentProcess();
 918     DWORD_PTR dwProcMask, dwSysMask;
 919     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 920     {
 921         wxLogLastError(_T("GetProcessAffinityMask"));
 922
 923         return false;
 924     }
 925
 926     // how many CPUs have we got?
 927     if ( dwSysMask == 1 )
 928     {
 929         // don't bother with all this complicated stuff - on a single
 930         // processor system it doesn't make much sense anyhow
 931         return level == 1;
 932     }
 933
 934     // calculate the process mask: it's a bit vector with one bit per
 935     // processor; we want to schedule the process to run on first level
 936     // CPUs
 937     DWORD bit = 1;
 938     while ( bit )
 939     {
 940         if ( dwSysMask & bit )
 941         {
 942             // ok, we can set this bit
 943             dwProcMask |= bit;
 944
 945             // another process added
 946             if ( --level == 0 )
 947             {
 948                 // and that's enough
 949                 break;
 950             }
 951         }
 952
 953         // next bit
 954         bit <<= 1;
 955     }
 956
 957     // could we set all bits?
 958     if ( level != 0 )
 959     {
 960         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 961
 962         return false;
 963     }
 964
 965     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 966     // exist in Win9x, use RT binding instead
 967
 968     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
 969
 970     // can use static var because we're always in the main thread here
 971     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
 972
 973     if ( !pfnSetProcessAffinityMask )
 974     {
 975         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
 976         if ( hModKernel )
 977         {
 978             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
 979                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
 980         }
 981
 982         // we've discovered a MT version of Win9x!
 983         wxASSERT_MSG( pfnSetProcessAffinityMask,
 984                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
 985     }
 986
 987     if ( !pfnSetProcessAffinityMask )
 988     {
 989         // msg given above - do it only once
 990         return false;
 991     }
 992
 993     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
 994     {
 995         wxLogLastError(_T("SetProcessAffinityMask"));
 996
 997         return false;
 998     }
 999
1000     return true;
1001 #endif // __WXWINCE__/!__WXWINCE__
1002 }
1003
1004 // ctor and dtor
1005 // -------------
1006
1007 wxThread::wxThread(wxThreadKind kind)
1008 {
1009     m_internal = new wxThreadInternal(this);
1010
1011     m_isDetached = kind == wxTHREAD_DETACHED;
1012 }
1013
1014 wxThread::~wxThread()
1015 {
1016     delete m_internal;
1017 }
1018
1019 // create/start thread
1020 // -------------------
1021
1022 wxThreadError wxThread::Create(unsigned int stackSize)
1023 {
1024     wxCriticalSectionLocker lock(m_critsect);
1025
1026     if ( !m_internal->Create(this, stackSize) )
1027         return wxTHREAD_NO_RESOURCE;
1028
1029     return wxTHREAD_NO_ERROR;
1030 }
1031
1032 wxThreadError wxThread::Run()
1033 {
1034     wxCriticalSectionLocker lock(m_critsect);
1035
1036     if ( m_internal->GetState() != STATE_NEW )
1037     {
1038         // actually, it may be almost any state at all, not only STATE_RUNNING
1039         return wxTHREAD_RUNNING;
1040     }
1041
1042     // the thread has just been created and is still suspended - let it run
1043     return Resume();
1044 }
1045
1046 // suspend/resume thread
1047 // ---------------------
1048
1049 wxThreadError wxThread::Pause()
1050 {
1051     wxCriticalSectionLocker lock(m_critsect);
1052
1053     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1054 }
1055
1056 wxThreadError wxThread::Resume()
1057 {
1058     wxCriticalSectionLocker lock(m_critsect);
1059
1060     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1061 }
1062
1063 // stopping thread
1064 // ---------------
1065
1066 wxThread::ExitCode wxThread::Wait()
1067 {
1068     // although under Windows we can wait for any thread, it's an error to
1069     // wait for a detached one in wxWin API
1070     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
1071                  _T("wxThread::Wait(): can't wait for detached thread") );
1072
1073     ExitCode rc = (ExitCode)-1;
1074
1075     (void)m_internal->WaitForTerminate(m_critsect, &rc);
1076
1077     return rc;
1078 }
1079
1080 wxThreadError wxThread::Delete(ExitCode *pRc)
1081 {
1082     return m_internal->WaitForTerminate(m_critsect, pRc, this);
1083 }
1084
1085 wxThreadError wxThread::Kill()
1086 {
1087     if ( !IsRunning() )
1088         return wxTHREAD_NOT_RUNNING;
1089
1090     wxThreadError rc = m_internal->Kill();
1091
1092     if ( IsDetached() )
1093     {
1094         delete this;
1095     }
1096     else // joinable
1097     {
1098         // update the status of the joinable thread
1099         wxCriticalSectionLocker lock(m_critsect);
1100         m_internal->SetState(STATE_EXITED);
1101     }
1102
1103     return rc;
1104 }
1105
1106 void wxThread::Exit(ExitCode status)
1107 {
1108     m_internal->Free();
1109
1110     if ( IsDetached() )
1111     {
1112         delete this;
1113     }
1114     else // joinable
1115     {
1116         // update the status of the joinable thread
1117         wxCriticalSectionLocker lock(m_critsect);
1118         m_internal->SetState(STATE_EXITED);
1119     }
1120
1121 #ifdef wxUSE_BEGIN_THREAD
1122     _endthreadex((unsigned)status);
1123 #else // !VC++
1124     ::ExitThread((DWORD)status);
1125 #endif // VC++/!VC++
1126
1127     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1128 }
1129
1130 // priority setting
1131 // ----------------
1132
1133 void wxThread::SetPriority(unsigned int prio)
1134 {
1135     wxCriticalSectionLocker lock(m_critsect);
1136
1137     m_internal->SetPriority(prio);
1138 }
1139
1140 unsigned int wxThread::GetPriority() const
1141 {
1142     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1143
1144     return m_internal->GetPriority();
1145 }
1146
1147 unsigned long wxThread::GetId() const
1148 {
1149     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1150
1151     return (unsigned long)m_internal->GetId();
1152 }
1153
1154 bool wxThread::IsRunning() const
1155 {
1156     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1157
1158     return m_internal->GetState() == STATE_RUNNING;
1159 }
1160
1161 bool wxThread::IsAlive() const
1162 {
1163     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1164
1165     return (m_internal->GetState() == STATE_RUNNING) ||
1166            (m_internal->GetState() == STATE_PAUSED);
1167 }
1168
1169 bool wxThread::IsPaused() const
1170 {
1171     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1172
1173     return m_internal->GetState() == STATE_PAUSED;
1174 }
1175
1176 bool wxThread::TestDestroy()
1177 {
1178     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1179
1180     return m_internal->GetState() == STATE_CANCELED;
1181 }
1182
1183 // ----------------------------------------------------------------------------
1184 // Automatic initialization for thread module
1185 // ----------------------------------------------------------------------------
1186
1187 class wxThreadModule : public wxModule
1188 {
1189 public:
1190     virtual bool OnInit();
1191     virtual void OnExit();
1192
1193 private:
1194     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1195 };
1196
1197 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1198
1199 bool wxThreadModule::OnInit()
1200 {
1201     // allocate TLS index for storing the pointer to the current thread
1202     gs_tlsThisThread = ::TlsAlloc();
1203     if ( gs_tlsThisThread == 0xFFFFFFFF )
1204     {
1205         // in normal circumstances it will only happen if all other
1206         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1207         // words, this should never happen
1208         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1209
1210         return false;
1211     }
1212
1213     // main thread doesn't have associated wxThread object, so store 0 in the
1214     // TLS instead
1215     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1216     {
1217         ::TlsFree(gs_tlsThisThread);
1218         gs_tlsThisThread = 0xFFFFFFFF;
1219
1220         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1221
1222         return false;
1223     }
1224
1225     gs_critsectWaitingForGui = new wxCriticalSection();
1226
1227     gs_critsectGui = new wxCriticalSection();
1228     gs_critsectGui->Enter();
1229
1230     gs_critsectThreadDelete = new wxCriticalSection;
1231
1232     // no error return for GetCurrentThreadId()
1233     gs_idMainThread = ::GetCurrentThreadId();
1234
1235     return true;
1236 }
1237
1238 void wxThreadModule::OnExit()
1239 {
1240     if ( !::TlsFree(gs_tlsThisThread) )
1241     {
1242         wxLogLastError(wxT("TlsFree failed."));
1243     }
1244
1245     delete gs_critsectThreadDelete;
1246     gs_critsectThreadDelete = NULL;
1247
1248     if ( gs_critsectGui )
1249     {
1250         gs_critsectGui->Leave();
1251         delete gs_critsectGui;
1252         gs_critsectGui = NULL;
1253     }
1254
1255     delete gs_critsectWaitingForGui;
1256     gs_critsectWaitingForGui = NULL;
1257 }
1258
1259 // ----------------------------------------------------------------------------
1260 // under Windows, these functions are implemented using a critical section and
1261 // not a mutex, so the names are a bit confusing
1262 // ----------------------------------------------------------------------------
1263
1264 void WXDLLIMPEXP_BASE wxMutexGuiEnter()
1265 {
1266     // this would dead lock everything...
1267     wxASSERT_MSG( !wxThread::IsMain(),
1268                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1269
1270     // the order in which we enter the critical sections here is crucial!!
1271
1272     // set the flag telling to the main thread that we want to do some GUI
1273     {
1274         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1275
1276         gs_nWaitingForGui++;
1277     }
1278
1279     wxWakeUpMainThread();
1280
1281     // now we may block here because the main thread will soon let us in
1282     // (during the next iteration of OnIdle())
1283     gs_critsectGui->Enter();
1284 }
1285
1286 void WXDLLIMPEXP_BASE wxMutexGuiLeave()
1287 {
1288     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1289
1290     if ( wxThread::IsMain() )
1291     {
1292         gs_bGuiOwnedByMainThread = false;
1293     }
1294     else
1295     {
1296         // decrement the number of threads waiting for GUI access now
1297         wxASSERT_MSG( gs_nWaitingForGui > 0,
1298                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1299
1300         gs_nWaitingForGui--;
1301
1302         wxWakeUpMainThread();
1303     }
1304
1305     gs_critsectGui->Leave();
1306 }
1307
1308 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1309 {
1310     wxASSERT_MSG( wxThread::IsMain(),
1311                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1312
1313     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1314
1315     if ( gs_nWaitingForGui == 0 )
1316     {
1317         // no threads are waiting for GUI - so we may acquire the lock without
1318         // any danger (but only if we don't already have it)
1319         if ( !wxGuiOwnedByMainThread() )
1320         {
1321             gs_critsectGui->Enter();
1322
1323             gs_bGuiOwnedByMainThread = true;
1324         }
1325         //else: already have it, nothing to do
1326     }
1327     else
1328     {
1329         // some threads are waiting, release the GUI lock if we have it
1330         if ( wxGuiOwnedByMainThread() )
1331         {
1332             wxMutexGuiLeave();
1333         }
1334         //else: some other worker thread is doing GUI
1335     }
1336 }
1337
1338 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1339 {
1340     return gs_bGuiOwnedByMainThread;
1341 }
1342
1343 // wake up the main thread if it's in ::GetMessage()
1344 void WXDLLIMPEXP_BASE wxWakeUpMainThread()
1345 {
1346     // sending any message would do - hopefully WM_NULL is harmless enough
1347     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1348     {
1349         // should never happen
1350         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1351     }
1352 }
1353
1354 bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
1355 {
1356     return gs_waitingForThread;
1357 }
1358
1359 // ----------------------------------------------------------------------------
1360 // include common implementation code
1361 // ----------------------------------------------------------------------------
1362
1363 #include "wx/thrimpl.cpp"
1364
1365 #endif // wxUSE_THREADS
1366