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     #include "wx/module.h"
  32 #endif
  33
  34 #include "wx/apptrait.h"
  35 #include "wx/scopeguard.h"
  36
  37 #include "wx/msw/private.h"
  38 #include "wx/msw/missing.h"
  39 #include "wx/msw/seh.h"
  40
  41 #include "wx/except.h"
  42
  43 // must have this symbol defined to get _beginthread/_endthread declarations
  44 #ifndef _MT
  45     #define _MT
  46 #endif
  47
  48 #if defined(__BORLANDC__)
  49     #if !defined(__MT__)
  50         // I can't set -tWM in the IDE (anyone?) so have to do this
  51         #define __MT__
  52     #endif
  53
  54     #if !defined(__MFC_COMPAT__)
  55         // Needed to know about _beginthreadex etc..
  56         #define __MFC_COMPAT__
  57     #endif
  58 #endif // BC++
  59
  60 // define wxUSE_BEGIN_THREAD if the compiler has _beginthreadex() function
  61 // which should be used instead of Win32 ::CreateThread() if possible
  62 #if defined(__VISUALC__) || \
  63     (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \
  64     (defined(__GNUG__) && defined(__MSVCRT__)) || \
  65     defined(__WATCOMC__) || defined(__MWERKS__)
  66
  67 #ifndef __WXWINCE__
  68     #undef wxUSE_BEGIN_THREAD
  69     #define wxUSE_BEGIN_THREAD
  70 #endif
  71
  72 #endif
  73
  74 #ifdef wxUSE_BEGIN_THREAD
  75     // this is where _beginthreadex() is declared
  76     #include <process.h>
  77
  78     // the return type of the thread function entry point
  79     typedef unsigned THREAD_RETVAL;
  80
  81     // the calling convention of the thread function entry point
  82     #define THREAD_CALLCONV __stdcall
  83 #else
  84     // the settings for CreateThread()
  85     typedef DWORD THREAD_RETVAL;
  86     #define THREAD_CALLCONV WINAPI
  87 #endif
  88
  89 // ----------------------------------------------------------------------------
  90 // constants
  91 // ----------------------------------------------------------------------------
  92
  93 // the possible states of the thread ("=>" shows all possible transitions from
  94 // this state)
  95 enum wxThreadState
  96 {
  97     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  98     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  99     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
 100     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
 101     STATE_EXITED        // thread is terminating
 102 };
 103
 104 // ----------------------------------------------------------------------------
 105 // this module globals
 106 // ----------------------------------------------------------------------------
 107
 108 // TLS index of the slot where we store the pointer to the current thread
 109 static DWORD gs_tlsThisThread = 0xFFFFFFFF;
 110
 111 // id of the main thread - the one which can call GUI functions without first
 112 // calling wxMutexGuiEnter()
 113 static DWORD gs_idMainThread = 0;
 114
 115 // if it's false, some secondary thread is holding the GUI lock
 116 static bool gs_bGuiOwnedByMainThread = true;
 117
 118 // critical section which controls access to all GUI functions: any secondary
 119 // thread (i.e. except the main one) must enter this crit section before doing
 120 // any GUI calls
 121 static wxCriticalSection *gs_critsectGui = NULL;
 122
 123 // critical section which protects gs_nWaitingForGui variable
 124 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
 125
 126 // critical section which serializes WinThreadStart() and WaitForTerminate()
 127 // (this is a potential bottleneck, we use a single crit sect for all threads
 128 // in the system, but normally time spent inside it should be quite short)
 129 static wxCriticalSection *gs_critsectThreadDelete = NULL;
 130
 131 // number of threads waiting for GUI in wxMutexGuiEnter()
 132 static size_t gs_nWaitingForGui = 0;
 133
 134 // are we waiting for a thread termination?
 135 static bool gs_waitingForThread = false;
 136
 137 // ============================================================================
 138 // Windows implementation of thread and related classes
 139 // ============================================================================
 140
 141 // ----------------------------------------------------------------------------
 142 // wxCriticalSection
 143 // ----------------------------------------------------------------------------
 144
 145 wxCriticalSection::wxCriticalSection()
 146 {
 147     wxCOMPILE_TIME_ASSERT( sizeof(CRITICAL_SECTION) <= sizeof(wxCritSectBuffer),
 148                            wxCriticalSectionBufferTooSmall );
 149
 150     ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
 151 }
 152
 153 wxCriticalSection::~wxCriticalSection()
 154 {
 155     ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
 156 }
 157
 158 void wxCriticalSection::Enter()
 159 {
 160     ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
 161 }
 162
 163 void wxCriticalSection::Leave()
 164 {
 165     ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
 166 }
 167
 168 // ----------------------------------------------------------------------------
 169 // wxMutex
 170 // ----------------------------------------------------------------------------
 171
 172 class wxMutexInternal
 173 {
 174 public:
 175     wxMutexInternal(wxMutexType mutexType);
 176     ~wxMutexInternal();
 177
 178     bool IsOk() const { return m_mutex != NULL; }
 179
 180     wxMutexError Lock() { return LockTimeout(INFINITE); }
 181     wxMutexError Lock(unsigned long ms) { return LockTimeout(ms); }
 182     wxMutexError TryLock();
 183     wxMutexError Unlock();
 184
 185 private:
 186     wxMutexError LockTimeout(DWORD milliseconds);
 187
 188     HANDLE m_mutex;
 189
 190     DECLARE_NO_COPY_CLASS(wxMutexInternal)
 191 };
 192
 193 // all mutexes are recursive under Win32 so we don't use mutexType
 194 wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
 195 {
 196     // create a nameless (hence intra process and always private) mutex
 197     m_mutex = ::CreateMutex
 198                 (
 199                     NULL,       // default secutiry attributes
 200                     FALSE,      // not initially locked
 201                     NULL        // no name
 202                 );
 203
 204     if ( !m_mutex )
 205     {
 206         wxLogLastError(_T("CreateMutex()"));
 207     }
 208 }
 209
 210 wxMutexInternal::~wxMutexInternal()
 211 {
 212     if ( m_mutex )
 213     {
 214         if ( !::CloseHandle(m_mutex) )
 215         {
 216             wxLogLastError(_T("CloseHandle(mutex)"));
 217         }
 218     }
 219 }
 220
 221 wxMutexError wxMutexInternal::TryLock()
 222 {
 223     const wxMutexError rc = LockTimeout(0);
 224
 225     // we have a special return code for timeout in this case
 226     return rc == wxMUTEX_TIMEOUT ? wxMUTEX_BUSY : rc;
 227 }
 228
 229 wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
 230 {
 231     DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
 232     if ( rc == WAIT_ABANDONED )
 233     {
 234         // the previous caller died without releasing the mutex, but now we can
 235         // really lock it
 236         wxLogDebug(_T("WaitForSingleObject() returned WAIT_ABANDONED"));
 237
 238         // use 0 timeout, normally we should always get it
 239         rc = ::WaitForSingleObject(m_mutex, 0);
 240     }
 241
 242     switch ( rc )
 243     {
 244         case WAIT_OBJECT_0:
 245             // ok
 246             break;
 247
 248         case WAIT_TIMEOUT:
 249             return wxMUTEX_TIMEOUT;
 250
 251         case WAIT_ABANDONED:        // checked for above
 252         default:
 253             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 254             // fall through
 255
 256         case WAIT_FAILED:
 257             wxLogLastError(_T("WaitForSingleObject(mutex)"));
 258             return wxMUTEX_MISC_ERROR;
 259     }
 260
 261     return wxMUTEX_NO_ERROR;
 262 }
 263
 264 wxMutexError wxMutexInternal::Unlock()
 265 {
 266     if ( !::ReleaseMutex(m_mutex) )
 267     {
 268         wxLogLastError(_T("ReleaseMutex()"));
 269
 270         return wxMUTEX_MISC_ERROR;
 271     }
 272
 273     return wxMUTEX_NO_ERROR;
 274 }
 275
 276 // --------------------------------------------------------------------------
 277 // wxSemaphore
 278 // --------------------------------------------------------------------------
 279
 280 // a trivial wrapper around Win32 semaphore
 281 class wxSemaphoreInternal
 282 {
 283 public:
 284     wxSemaphoreInternal(int initialcount, int maxcount);
 285     ~wxSemaphoreInternal();
 286
 287     bool IsOk() const { return m_semaphore != NULL; }
 288
 289     wxSemaError Wait() { return WaitTimeout(INFINITE); }
 290
 291     wxSemaError TryWait()
 292     {
 293         wxSemaError rc = WaitTimeout(0);
 294         if ( rc == wxSEMA_TIMEOUT )
 295             rc = wxSEMA_BUSY;
 296
 297         return rc;
 298     }
 299
 300     wxSemaError WaitTimeout(unsigned long milliseconds);
 301
 302     wxSemaError Post();
 303
 304 private:
 305     HANDLE m_semaphore;
 306
 307     DECLARE_NO_COPY_CLASS(wxSemaphoreInternal)
 308 };
 309
 310 wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
 311 {
 312 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
 313     if ( maxcount == 0 )
 314     {
 315         // make it practically infinite
 316         maxcount = INT_MAX;
 317     }
 318
 319     m_semaphore = ::CreateSemaphore
 320                     (
 321                         NULL,           // default security attributes
 322                         initialcount,
 323                         maxcount,
 324                         NULL            // no name
 325                     );
 326 #endif
 327     if ( !m_semaphore )
 328     {
 329         wxLogLastError(_T("CreateSemaphore()"));
 330     }
 331 }
 332
 333 wxSemaphoreInternal::~wxSemaphoreInternal()
 334 {
 335     if ( m_semaphore )
 336     {
 337         if ( !::CloseHandle(m_semaphore) )
 338         {
 339             wxLogLastError(_T("CloseHandle(semaphore)"));
 340         }
 341     }
 342 }
 343
 344 wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long milliseconds)
 345 {
 346     DWORD rc = ::WaitForSingleObject( m_semaphore, milliseconds );
 347
 348     switch ( rc )
 349     {
 350         case WAIT_OBJECT_0:
 351            return wxSEMA_NO_ERROR;
 352
 353         case WAIT_TIMEOUT:
 354            return wxSEMA_TIMEOUT;
 355
 356         default:
 357             wxLogLastError(_T("WaitForSingleObject(semaphore)"));
 358     }
 359
 360     return wxSEMA_MISC_ERROR;
 361 }
 362
 363 wxSemaError wxSemaphoreInternal::Post()
 364 {
 365 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
 366     if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
 367     {
 368         if ( GetLastError() == ERROR_TOO_MANY_POSTS )
 369         {
 370             return wxSEMA_OVERFLOW;
 371         }
 372         else
 373         {
 374             wxLogLastError(_T("ReleaseSemaphore"));
 375             return wxSEMA_MISC_ERROR;
 376         }
 377     }
 378
 379     return wxSEMA_NO_ERROR;
 380 #else
 381     return wxSEMA_MISC_ERROR;
 382 #endif
 383 }
 384
 385 // ----------------------------------------------------------------------------
 386 // wxThread implementation
 387 // ----------------------------------------------------------------------------
 388
 389 // wxThreadInternal class
 390 // ----------------------
 391
 392 class wxThreadInternal
 393 {
 394 public:
 395     wxThreadInternal(wxThread *thread)
 396     {
 397         m_thread = thread;
 398         m_hThread = 0;
 399         m_state = STATE_NEW;
 400         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 401         m_nRef = 1;
 402     }
 403
 404     ~wxThreadInternal()
 405     {
 406         Free();
 407     }
 408
 409     void Free()
 410     {
 411         if ( m_hThread )
 412         {
 413             if ( !::CloseHandle(m_hThread) )
 414             {
 415                 wxLogLastError(wxT("CloseHandle(thread)"));
 416             }
 417
 418             m_hThread = 0;
 419         }
 420     }
 421
 422     // create a new (suspended) thread (for the given thread object)
 423     bool Create(wxThread *thread, unsigned int stackSize);
 424
 425     // wait for the thread to terminate, either by itself, or by asking it
 426     // (politely, this is not Kill()!) to do it
 427     wxThreadError WaitForTerminate(wxCriticalSection& cs,
 428                                    wxThread::ExitCode *pRc,
 429                                    wxThread *threadToDelete = NULL);
 430
 431     // kill the thread unconditionally
 432     wxThreadError Kill();
 433
 434     // suspend/resume/terminate
 435     bool Suspend();
 436     bool Resume();
 437     void Cancel() { m_state = STATE_CANCELED; }
 438
 439     // thread state
 440     void SetState(wxThreadState state) { m_state = state; }
 441     wxThreadState GetState() const { return m_state; }
 442
 443     // thread priority
 444     void SetPriority(unsigned int priority);
 445     unsigned int GetPriority() const { return m_priority; }
 446
 447     // thread handle and id
 448     HANDLE GetHandle() const { return m_hThread; }
 449     DWORD  GetId() const { return m_tid; }
 450
 451     // the thread function forwarding to DoThreadStart
 452     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 453
 454     // really start the thread (if it's not already dead)
 455     static THREAD_RETVAL DoThreadStart(wxThread *thread);
 456
 457     // call OnExit() on the thread
 458     static void DoThreadOnExit(wxThread *thread);
 459
 460
 461     void KeepAlive()
 462     {
 463         if ( m_thread->IsDetached() )
 464             ::InterlockedIncrement(&m_nRef);
 465     }
 466
 467     void LetDie()
 468     {
 469         if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
 470             delete m_thread;
 471     }
 472
 473 private:
 474     // the thread we're associated with
 475     wxThread *m_thread;
 476
 477     HANDLE        m_hThread;    // handle of the thread
 478     wxThreadState m_state;      // state, see wxThreadState enum
 479     unsigned int  m_priority;   // thread priority in "wx" units
 480     DWORD         m_tid;        // thread id
 481
 482     // number of threads which need this thread to remain alive, when the count
 483     // reaches 0 we kill the owning wxThread -- and die ourselves with it
 484     LONG m_nRef;
 485
 486     DECLARE_NO_COPY_CLASS(wxThreadInternal)
 487 };
 488
 489 // small class which keeps a thread alive during its lifetime
 490 class wxThreadKeepAlive
 491 {
 492 public:
 493     wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
 494         { m_thrImpl.KeepAlive(); }
 495     ~wxThreadKeepAlive()
 496         { m_thrImpl.LetDie(); }
 497
 498 private:
 499     wxThreadInternal& m_thrImpl;
 500 };
 501
 502 /* static */
 503 void wxThreadInternal::DoThreadOnExit(wxThread *thread)
 504 {
 505     wxTRY
 506     {
 507         thread->OnExit();
 508     }
 509     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 510 }
 511
 512 /* static */
 513 THREAD_RETVAL wxThreadInternal::DoThreadStart(wxThread *thread)
 514 {
 515     wxON_BLOCK_EXIT1(DoThreadOnExit, thread);
 516
 517     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 518
 519     wxTRY
 520     {
 521         // store the thread object in the TLS
 522         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 523         {
 524             wxLogSysError(_("Can not start thread: error writing TLS."));
 525
 526             return (THREAD_RETVAL)-1;
 527         }
 528
 529         rc = (THREAD_RETVAL)thread->Entry();
 530     }
 531     wxCATCH_ALL( wxTheApp->OnUnhandledException(); )
 532
 533     return rc;
 534 }
 535
 536 /* static */
 537 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 538 {
 539     THREAD_RETVAL rc = (THREAD_RETVAL)-1;
 540
 541     wxThread * const thread = (wxThread *)param;
 542
 543     // each thread has its own SEH translator so install our own a.s.a.p.
 544     DisableAutomaticSETranslator();
 545
 546     // first of all, check whether we hadn't been cancelled already and don't
 547     // start the user code at all then
 548     const bool hasExited = thread->m_internal->GetState() == STATE_EXITED;
 549
 550     // run the thread function itself inside a SEH try/except block
 551     wxSEH_TRY
 552     {
 553         if ( hasExited )
 554             DoThreadOnExit(thread);
 555         else
 556             rc = DoThreadStart(thread);
 557     }
 558     wxSEH_HANDLE((THREAD_RETVAL)-1)
 559
 560
 561     // save IsDetached because thread object can be deleted by joinable
 562     // threads after state is changed to STATE_EXITED.
 563     const bool isDetached = thread->IsDetached();
 564     if ( !hasExited )
 565     {
 566         // enter m_critsect before changing the thread state
 567         //
 568         // NB: can't use wxCriticalSectionLocker here as we use SEH and it's
 569         //     incompatible with C++ object dtors
 570         thread->m_critsect.Enter();
 571         thread->m_internal->SetState(STATE_EXITED);
 572         thread->m_critsect.Leave();
 573     }
 574
 575     // the thread may delete itself now if it wants, we don't need it any more
 576     if ( isDetached )
 577         thread->m_internal->LetDie();
 578
 579     return rc;
 580 }
 581
 582 void wxThreadInternal::SetPriority(unsigned int priority)
 583 {
 584     m_priority = priority;
 585
 586     // translate wxWidgets priority to the Windows one
 587     int win_priority;
 588     if (m_priority <= 20)
 589         win_priority = THREAD_PRIORITY_LOWEST;
 590     else if (m_priority <= 40)
 591         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 592     else if (m_priority <= 60)
 593         win_priority = THREAD_PRIORITY_NORMAL;
 594     else if (m_priority <= 80)
 595         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 596     else if (m_priority <= 100)
 597         win_priority = THREAD_PRIORITY_HIGHEST;
 598     else
 599     {
 600         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 601         win_priority = THREAD_PRIORITY_NORMAL;
 602     }
 603
 604     if ( !::SetThreadPriority(m_hThread, win_priority) )
 605     {
 606         wxLogSysError(_("Can't set thread priority"));
 607     }
 608 }
 609
 610 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 611 {
 612     wxASSERT_MSG( m_state == STATE_NEW && !m_hThread,
 613                     _T("Create()ing thread twice?") );
 614
 615     // for compilers which have it, we should use C RTL function for thread
 616     // creation instead of Win32 API one because otherwise we will have memory
 617     // leaks if the thread uses C RTL (and most threads do)
 618 #ifdef wxUSE_BEGIN_THREAD
 619
 620     // Watcom is reported to not like 0 stack size (which means "use default"
 621     // for the other compilers and is also the default value for stackSize)
 622 #ifdef __WATCOMC__
 623     if ( !stackSize )
 624         stackSize = 10240;
 625 #endif // __WATCOMC__
 626
 627     m_hThread = (HANDLE)_beginthreadex
 628                         (
 629                           NULL,                             // default security
 630                           stackSize,
 631                           wxThreadInternal::WinThreadStart, // entry point
 632                           thread,
 633                           CREATE_SUSPENDED,
 634                           (unsigned int *)&m_tid
 635                         );
 636 #else // compiler doesn't have _beginthreadex
 637     m_hThread = ::CreateThread
 638                   (
 639                     NULL,                               // default security
 640                     stackSize,                          // stack size
 641                     wxThreadInternal::WinThreadStart,   // thread entry point
 642                     (LPVOID)thread,                     // parameter
 643                     CREATE_SUSPENDED,                   // flags
 644                     &m_tid                              // [out] thread id
 645                   );
 646 #endif // _beginthreadex/CreateThread
 647
 648     if ( m_hThread == NULL )
 649     {
 650         wxLogSysError(_("Can't create thread"));
 651
 652         return false;
 653     }
 654
 655     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 656     {
 657         SetPriority(m_priority);
 658     }
 659
 660     return true;
 661 }
 662
 663 wxThreadError wxThreadInternal::Kill()
 664 {
 665     if ( !::TerminateThread(m_hThread, (DWORD)-1) )
 666     {
 667         wxLogSysError(_("Couldn't terminate thread"));
 668
 669         return wxTHREAD_MISC_ERROR;
 670     }
 671
 672     Free();
 673
 674     return wxTHREAD_NO_ERROR;
 675 }
 676
 677 wxThreadError
 678 wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
 679                                    wxThread::ExitCode *pRc,
 680                                    wxThread *threadToDelete)
 681 {
 682     // prevent the thread C++ object from disappearing as long as we are using
 683     // it here
 684     wxThreadKeepAlive keepAlive(*this);
 685
 686
 687     // we may either wait passively for the thread to terminate (when called
 688     // from Wait()) or ask it to terminate (when called from Delete())
 689     bool shouldDelete = threadToDelete != NULL;
 690
 691     wxThread::ExitCode rc = 0;
 692
 693     // we might need to resume the thread if it's currently stopped
 694     bool shouldResume = false;
 695
 696     // as Delete() (which calls us) is always safe to call we need to consider
 697     // all possible states
 698     {
 699         wxCriticalSectionLocker lock(cs);
 700
 701         if ( m_state == STATE_NEW )
 702         {
 703             if ( shouldDelete )
 704             {
 705                 // WinThreadStart() will see it and terminate immediately, no
 706                 // need to cancel the thread -- but we still need to resume it
 707                 // to let it run
 708                 m_state = STATE_EXITED;
 709
 710                 // we must call Resume() as the thread hasn't been initially
 711                 // resumed yet (and as Resume() it knows about STATE_EXITED
 712                 // special case, it won't touch it and WinThreadStart() will
 713                 // just exit immediately)
 714                 shouldResume = true;
 715                 shouldDelete = false;
 716             }
 717             //else: shouldResume is correctly set to false here, wait until
 718             //      someone else runs the thread and it finishes
 719         }
 720         else // running, paused, cancelled or even exited
 721         {
 722             shouldResume = m_state == STATE_PAUSED;
 723         }
 724     }
 725
 726     // resume the thread if it is paused
 727     if ( shouldResume )
 728         Resume();
 729
 730     // ask the thread to terminate
 731     if ( shouldDelete )
 732     {
 733         wxCriticalSectionLocker lock(cs);
 734
 735         Cancel();
 736     }
 737
 738
 739     // now wait for thread to finish
 740     if ( wxThread::IsMain() )
 741     {
 742         // set flag for wxIsWaitingForThread()
 743         gs_waitingForThread = true;
 744     }
 745
 746     // we can't just wait for the thread to terminate because it might be
 747     // calling some GUI functions and so it will never terminate before we
 748     // process the Windows messages that result from these functions
 749     // (note that even in console applications we might have to process
 750     // messages if we use wxExecute() or timers or ...)
 751     DWORD result wxDUMMY_INITIALIZE(0);
 752     do
 753     {
 754         if ( wxThread::IsMain() )
 755         {
 756             // give the thread we're waiting for chance to do the GUI call
 757             // it might be in
 758             if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 759             {
 760                 wxMutexGuiLeave();
 761             }
 762         }
 763
 764         wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
 765         if ( traits )
 766         {
 767             result = traits->WaitForThread(m_hThread);
 768         }
 769         else // can't wait for the thread
 770         {
 771             // so kill it below
 772             result = 0xFFFFFFFF;
 773         }
 774
 775         switch ( result )
 776         {
 777             case 0xFFFFFFFF:
 778                 // error
 779                 wxLogSysError(_("Can not wait for thread termination"));
 780                 Kill();
 781                 return wxTHREAD_KILLED;
 782
 783             case WAIT_OBJECT_0:
 784                 // thread we're waiting for terminated
 785                 break;
 786
 787             case WAIT_OBJECT_0 + 1:
 788                 // new message arrived, process it -- but only if we're the
 789                 // main thread as we don't support processing messages in
 790                 // the other ones
 791                 //
 792                 // NB: we still must include QS_ALLINPUT even when waiting
 793                 //     in a secondary thread because if it had created some
 794                 //     window somehow (possible not even using wxWidgets)
 795                 //     the system might dead lock then
 796                 if ( wxThread::IsMain() )
 797                 {
 798                     if ( traits && !traits->DoMessageFromThreadWait() )
 799                     {
 800                         // WM_QUIT received: kill the thread
 801                         Kill();
 802
 803                         return wxTHREAD_KILLED;
 804                     }
 805                 }
 806                 break;
 807
 808             default:
 809                 wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
 810         }
 811     } while ( result != WAIT_OBJECT_0 );
 812
 813     if ( wxThread::IsMain() )
 814     {
 815         gs_waitingForThread = false;
 816     }
 817
 818
 819     // although the thread might be already in the EXITED state it might not
 820     // have terminated yet and so we are not sure that it has actually
 821     // terminated if the "if" above hadn't been taken
 822     for ( ;; )
 823     {
 824         if ( !::GetExitCodeThread(m_hThread, (LPDWORD)&rc) )
 825         {
 826             wxLogLastError(wxT("GetExitCodeThread"));
 827
 828             rc = (wxThread::ExitCode)-1;
 829
 830             break;
 831         }
 832
 833         if ( (DWORD)rc != STILL_ACTIVE )
 834             break;
 835
 836         // give the other thread some time to terminate, otherwise we may be
 837         // starving it
 838         ::Sleep(1);
 839     }
 840
 841     if ( pRc )
 842         *pRc = rc;
 843
 844     // we don't need the thread handle any more in any case
 845     Free();
 846
 847
 848     return rc == (wxThread::ExitCode)-1 ? wxTHREAD_MISC_ERROR
 849                                         : wxTHREAD_NO_ERROR;
 850 }
 851
 852 bool wxThreadInternal::Suspend()
 853 {
 854     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 855     if ( nSuspendCount == (DWORD)-1 )
 856     {
 857         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 858
 859         return false;
 860     }
 861
 862     m_state = STATE_PAUSED;
 863
 864     return true;
 865 }
 866
 867 bool wxThreadInternal::Resume()
 868 {
 869     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 870     if ( nSuspendCount == (DWORD)-1 )
 871     {
 872         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 873
 874         return false;
 875     }
 876
 877     // don't change the state from STATE_EXITED because it's special and means
 878     // we are going to terminate without running any user code - if we did it,
 879     // the code in WaitForTerminate() wouldn't work
 880     if ( m_state != STATE_EXITED )
 881     {
 882         m_state = STATE_RUNNING;
 883     }
 884
 885     return true;
 886 }
 887
 888 // static functions
 889 // ----------------
 890
 891 wxThread *wxThread::This()
 892 {
 893     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 894
 895     // be careful, 0 may be a valid return value as well
 896     if ( !thread && (::GetLastError() != NO_ERROR) )
 897     {
 898         wxLogSysError(_("Couldn't get the current thread pointer"));
 899
 900         // return NULL...
 901     }
 902
 903     return thread;
 904 }
 905
 906 bool wxThread::IsMain()
 907 {
 908     return ::GetCurrentThreadId() == gs_idMainThread || gs_idMainThread == 0;
 909 }
 910
 911 void wxThread::Yield()
 912 {
 913     // 0 argument to Sleep() is special and means to just give away the rest of
 914     // our timeslice
 915     ::Sleep(0);
 916 }
 917
 918 void wxThread::Sleep(unsigned long milliseconds)
 919 {
 920     ::Sleep(milliseconds);
 921 }
 922
 923 int wxThread::GetCPUCount()
 924 {
 925     SYSTEM_INFO si;
 926     GetSystemInfo(&si);
 927
 928     return si.dwNumberOfProcessors;
 929 }
 930
 931 unsigned long wxThread::GetCurrentId()
 932 {
 933     return (unsigned long)::GetCurrentThreadId();
 934 }
 935
 936 bool wxThread::SetConcurrency(size_t WXUNUSED_IN_WINCE(level))
 937 {
 938 #ifdef __WXWINCE__
 939     return false;
 940 #else
 941     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 942
 943     // ok only for the default one
 944     if ( level == 0 )
 945         return 0;
 946
 947     // get system affinity mask first
 948     HANDLE hProcess = ::GetCurrentProcess();
 949     DWORD_PTR dwProcMask, dwSysMask;
 950     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 951     {
 952         wxLogLastError(_T("GetProcessAffinityMask"));
 953
 954         return false;
 955     }
 956
 957     // how many CPUs have we got?
 958     if ( dwSysMask == 1 )
 959     {
 960         // don't bother with all this complicated stuff - on a single
 961         // processor system it doesn't make much sense anyhow
 962         return level == 1;
 963     }
 964
 965     // calculate the process mask: it's a bit vector with one bit per
 966     // processor; we want to schedule the process to run on first level
 967     // CPUs
 968     DWORD bit = 1;
 969     while ( bit )
 970     {
 971         if ( dwSysMask & bit )
 972         {
 973             // ok, we can set this bit
 974             dwProcMask |= bit;
 975
 976             // another process added
 977             if ( --level == 0 )
 978             {
 979                 // and that's enough
 980                 break;
 981             }
 982         }
 983
 984         // next bit
 985         bit <<= 1;
 986     }
 987
 988     // could we set all bits?
 989     if ( level != 0 )
 990     {
 991         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 992
 993         return false;
 994     }
 995
 996     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 997     // exist in Win9x, use RT binding instead
 998
 999     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
1000
1001     // can use static var because we're always in the main thread here
1002     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
1003
1004     if ( !pfnSetProcessAffinityMask )
1005     {
1006         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
1007         if ( hModKernel )
1008         {
1009             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
1010                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
1011         }
1012
1013         // we've discovered a MT version of Win9x!
1014         wxASSERT_MSG( pfnSetProcessAffinityMask,
1015                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
1016     }
1017
1018     if ( !pfnSetProcessAffinityMask )
1019     {
1020         // msg given above - do it only once
1021         return false;
1022     }
1023
1024     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
1025     {
1026         wxLogLastError(_T("SetProcessAffinityMask"));
1027
1028         return false;
1029     }
1030
1031     return true;
1032 #endif // __WXWINCE__/!__WXWINCE__
1033 }
1034
1035 // ctor and dtor
1036 // -------------
1037
1038 wxThread::wxThread(wxThreadKind kind)
1039 {
1040     m_internal = new wxThreadInternal(this);
1041
1042     m_isDetached = kind == wxTHREAD_DETACHED;
1043 }
1044
1045 wxThread::~wxThread()
1046 {
1047     delete m_internal;
1048 }
1049
1050 // create/start thread
1051 // -------------------
1052
1053 wxThreadError wxThread::Create(unsigned int stackSize)
1054 {
1055     wxCriticalSectionLocker lock(m_critsect);
1056
1057     if ( !m_internal->Create(this, stackSize) )
1058         return wxTHREAD_NO_RESOURCE;
1059
1060     return wxTHREAD_NO_ERROR;
1061 }
1062
1063 wxThreadError wxThread::Run()
1064 {
1065     wxCriticalSectionLocker lock(m_critsect);
1066
1067     if ( m_internal->GetState() != STATE_NEW )
1068     {
1069         // actually, it may be almost any state at all, not only STATE_RUNNING
1070         return wxTHREAD_RUNNING;
1071     }
1072
1073     // the thread has just been created and is still suspended - let it run
1074     return Resume();
1075 }
1076
1077 // suspend/resume thread
1078 // ---------------------
1079
1080 wxThreadError wxThread::Pause()
1081 {
1082     wxCriticalSectionLocker lock(m_critsect);
1083
1084     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1085 }
1086
1087 wxThreadError wxThread::Resume()
1088 {
1089     wxCriticalSectionLocker lock(m_critsect);
1090
1091     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
1092 }
1093
1094 // stopping thread
1095 // ---------------
1096
1097 wxThread::ExitCode wxThread::Wait()
1098 {
1099     // although under Windows we can wait for any thread, it's an error to
1100     // wait for a detached one in wxWin API
1101     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
1102                  _T("wxThread::Wait(): can't wait for detached thread") );
1103
1104     ExitCode rc = (ExitCode)-1;
1105
1106     (void)m_internal->WaitForTerminate(m_critsect, &rc);
1107
1108     return rc;
1109 }
1110
1111 wxThreadError wxThread::Delete(ExitCode *pRc)
1112 {
1113     return m_internal->WaitForTerminate(m_critsect, pRc, this);
1114 }
1115
1116 wxThreadError wxThread::Kill()
1117 {
1118     if ( !IsRunning() )
1119         return wxTHREAD_NOT_RUNNING;
1120
1121     wxThreadError rc = m_internal->Kill();
1122
1123     if ( IsDetached() )
1124     {
1125         delete this;
1126     }
1127     else // joinable
1128     {
1129         // update the status of the joinable thread
1130         wxCriticalSectionLocker lock(m_critsect);
1131         m_internal->SetState(STATE_EXITED);
1132     }
1133
1134     return rc;
1135 }
1136
1137 void wxThread::Exit(ExitCode status)
1138 {
1139     m_internal->Free();
1140
1141     if ( IsDetached() )
1142     {
1143         delete this;
1144     }
1145     else // joinable
1146     {
1147         // update the status of the joinable thread
1148         wxCriticalSectionLocker lock(m_critsect);
1149         m_internal->SetState(STATE_EXITED);
1150     }
1151
1152 #ifdef wxUSE_BEGIN_THREAD
1153     _endthreadex((unsigned)status);
1154 #else // !VC++
1155     ::ExitThread((DWORD)status);
1156 #endif // VC++/!VC++
1157
1158     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1159 }
1160
1161 // priority setting
1162 // ----------------
1163
1164 void wxThread::SetPriority(unsigned int prio)
1165 {
1166     wxCriticalSectionLocker lock(m_critsect);
1167
1168     m_internal->SetPriority(prio);
1169 }
1170
1171 unsigned int wxThread::GetPriority() const
1172 {
1173     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1174
1175     return m_internal->GetPriority();
1176 }
1177
1178 unsigned long wxThread::GetId() const
1179 {
1180     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1181
1182     return (unsigned long)m_internal->GetId();
1183 }
1184
1185 bool wxThread::IsRunning() const
1186 {
1187     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1188
1189     return m_internal->GetState() == STATE_RUNNING;
1190 }
1191
1192 bool wxThread::IsAlive() const
1193 {
1194     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1195
1196     return (m_internal->GetState() == STATE_RUNNING) ||
1197            (m_internal->GetState() == STATE_PAUSED);
1198 }
1199
1200 bool wxThread::IsPaused() const
1201 {
1202     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1203
1204     return m_internal->GetState() == STATE_PAUSED;
1205 }
1206
1207 bool wxThread::TestDestroy()
1208 {
1209     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1210
1211     return m_internal->GetState() == STATE_CANCELED;
1212 }
1213
1214 // ----------------------------------------------------------------------------
1215 // Automatic initialization for thread module
1216 // ----------------------------------------------------------------------------
1217
1218 class wxThreadModule : public wxModule
1219 {
1220 public:
1221     virtual bool OnInit();
1222     virtual void OnExit();
1223
1224 private:
1225     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1226 };
1227
1228 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1229
1230 bool wxThreadModule::OnInit()
1231 {
1232     // allocate TLS index for storing the pointer to the current thread
1233     gs_tlsThisThread = ::TlsAlloc();
1234     if ( gs_tlsThisThread == 0xFFFFFFFF )
1235     {
1236         // in normal circumstances it will only happen if all other
1237         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1238         // words, this should never happen
1239         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1240
1241         return false;
1242     }
1243
1244     // main thread doesn't have associated wxThread object, so store 0 in the
1245     // TLS instead
1246     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1247     {
1248         ::TlsFree(gs_tlsThisThread);
1249         gs_tlsThisThread = 0xFFFFFFFF;
1250
1251         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1252
1253         return false;
1254     }
1255
1256     gs_critsectWaitingForGui = new wxCriticalSection();
1257
1258     gs_critsectGui = new wxCriticalSection();
1259     gs_critsectGui->Enter();
1260
1261     gs_critsectThreadDelete = new wxCriticalSection;
1262
1263     // no error return for GetCurrentThreadId()
1264     gs_idMainThread = ::GetCurrentThreadId();
1265
1266     return true;
1267 }
1268
1269 void wxThreadModule::OnExit()
1270 {
1271     if ( !::TlsFree(gs_tlsThisThread) )
1272     {
1273         wxLogLastError(wxT("TlsFree failed."));
1274     }
1275
1276     delete gs_critsectThreadDelete;
1277     gs_critsectThreadDelete = NULL;
1278
1279     if ( gs_critsectGui )
1280     {
1281         gs_critsectGui->Leave();
1282         delete gs_critsectGui;
1283         gs_critsectGui = NULL;
1284     }
1285
1286     delete gs_critsectWaitingForGui;
1287     gs_critsectWaitingForGui = NULL;
1288 }
1289
1290 // ----------------------------------------------------------------------------
1291 // under Windows, these functions are implemented using a critical section and
1292 // not a mutex, so the names are a bit confusing
1293 // ----------------------------------------------------------------------------
1294
1295 void WXDLLIMPEXP_BASE wxMutexGuiEnter()
1296 {
1297     // this would dead lock everything...
1298     wxASSERT_MSG( !wxThread::IsMain(),
1299                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1300
1301     // the order in which we enter the critical sections here is crucial!!
1302
1303     // set the flag telling to the main thread that we want to do some GUI
1304     {
1305         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1306
1307         gs_nWaitingForGui++;
1308     }
1309
1310     wxWakeUpMainThread();
1311
1312     // now we may block here because the main thread will soon let us in
1313     // (during the next iteration of OnIdle())
1314     gs_critsectGui->Enter();
1315 }
1316
1317 void WXDLLIMPEXP_BASE wxMutexGuiLeave()
1318 {
1319     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1320
1321     if ( wxThread::IsMain() )
1322     {
1323         gs_bGuiOwnedByMainThread = false;
1324     }
1325     else
1326     {
1327         // decrement the number of threads waiting for GUI access now
1328         wxASSERT_MSG( gs_nWaitingForGui > 0,
1329                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1330
1331         gs_nWaitingForGui--;
1332
1333         wxWakeUpMainThread();
1334     }
1335
1336     gs_critsectGui->Leave();
1337 }
1338
1339 void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
1340 {
1341     wxASSERT_MSG( wxThread::IsMain(),
1342                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1343
1344     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1345
1346     if ( gs_nWaitingForGui == 0 )
1347     {
1348         // no threads are waiting for GUI - so we may acquire the lock without
1349         // any danger (but only if we don't already have it)
1350         if ( !wxGuiOwnedByMainThread() )
1351         {
1352             gs_critsectGui->Enter();
1353
1354             gs_bGuiOwnedByMainThread = true;
1355         }
1356         //else: already have it, nothing to do
1357     }
1358     else
1359     {
1360         // some threads are waiting, release the GUI lock if we have it
1361         if ( wxGuiOwnedByMainThread() )
1362         {
1363             wxMutexGuiLeave();
1364         }
1365         //else: some other worker thread is doing GUI
1366     }
1367 }
1368
1369 bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
1370 {
1371     return gs_bGuiOwnedByMainThread;
1372 }
1373
1374 // wake up the main thread if it's in ::GetMessage()
1375 void WXDLLIMPEXP_BASE wxWakeUpMainThread()
1376 {
1377     // sending any message would do - hopefully WM_NULL is harmless enough
1378     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1379     {
1380         // should never happen
1381         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1382     }
1383 }
1384
1385 bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
1386 {
1387     return gs_waitingForThread;
1388 }
1389
1390 // ----------------------------------------------------------------------------
1391 // include common implementation code
1392 // ----------------------------------------------------------------------------
1393
1394 #include "wx/thrimpl.cpp"
1395
1396 #endif // wxUSE_THREADS