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 #ifdef __GNUG__
  14     #pragma implementation "thread.h"
  15 #endif
  16
  17 // ----------------------------------------------------------------------------
  18 // headers
  19 // ----------------------------------------------------------------------------
  20
  21 // For compilers that support precompilation, includes "wx.h".
  22 #include "wx/wxprec.h"
  23
  24 #if defined(__BORLANDC__)
  25     #pragma hdrstop
  26 #endif
  27
  28 #ifndef WX_PRECOMP
  29 #    include "wx/wx.h"
  30 #endif
  31
  32 #if wxUSE_THREADS
  33
  34 #include "wx/msw/private.h"
  35 #include "wx/msw/missing.h"
  36
  37 #include "wx/module.h"
  38 #include "wx/thread.h"
  39
  40 // must have this symbol defined to get _beginthread/_endthread declarations
  41 #ifndef _MT
  42     #define _MT
  43 #endif
  44
  45 #if defined(__BORLANDC__)
  46     #if !defined(__MT__)
  47         // I can't set -tWM in the IDE (anyone?) so have to do this
  48         #define __MT__
  49     #endif
  50
  51     #if !defined(__MFC_COMPAT__)
  52         // Needed to know about _beginthreadex etc..
  53         #define __MFC_COMPAT__
  54     #endif
  55 #endif // BC++
  56
  57 // define wxUSE_BEGIN_THREAD if the compiler has _beginthreadex() function
  58 // which should be used instead of Win32 ::CreateThread() if possible
  59 #if defined(__VISUALC__) || \
  60     (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \
  61     (defined(__GNUG__) && defined(__MSVCRT__)) || \
  62     defined(__WATCOMC__) || defined(__MWERKS__)
  63
  64     #undef wxUSE_BEGIN_THREAD
  65     #define wxUSE_BEGIN_THREAD
  66 #endif
  67
  68 #ifdef wxUSE_BEGIN_THREAD
  69     // this is where _beginthreadex() is declared
  70     #include <process.h>
  71
  72     // the return type of the thread function entry point
  73     typedef unsigned THREAD_RETVAL;
  74
  75     // the calling convention of the thread function entry point
  76     #define THREAD_CALLCONV __stdcall
  77 #else
  78     // the settings for CreateThread()
  79     typedef DWORD THREAD_RETVAL;
  80     #define THREAD_CALLCONV WINAPI
  81 #endif
  82
  83 // ----------------------------------------------------------------------------
  84 // constants
  85 // ----------------------------------------------------------------------------
  86
  87 // the possible states of the thread ("=>" shows all possible transitions from
  88 // this state)
  89 enum wxThreadState
  90 {
  91     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  92     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  93     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
  94     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
  95     STATE_EXITED        // thread is terminating
  96 };
  97
  98 // ----------------------------------------------------------------------------
  99 // this module globals
 100 // ----------------------------------------------------------------------------
 101
 102 // TLS index of the slot where we store the pointer to the current thread
 103 static DWORD gs_tlsThisThread = 0xFFFFFFFF;
 104
 105 // id of the main thread - the one which can call GUI functions without first
 106 // calling wxMutexGuiEnter()
 107 static DWORD gs_idMainThread = 0;
 108
 109 // if it's FALSE, some secondary thread is holding the GUI lock
 110 static bool gs_bGuiOwnedByMainThread = TRUE;
 111
 112 // critical section which controls access to all GUI functions: any secondary
 113 // thread (i.e. except the main one) must enter this crit section before doing
 114 // any GUI calls
 115 static wxCriticalSection *gs_critsectGui = NULL;
 116
 117 // critical section which protects gs_nWaitingForGui variable
 118 static wxCriticalSection *gs_critsectWaitingForGui = NULL;
 119
 120 // number of threads waiting for GUI in wxMutexGuiEnter()
 121 static size_t gs_nWaitingForGui = 0;
 122
 123 // are we waiting for a thread termination?
 124 static bool gs_waitingForThread = FALSE;
 125
 126 // ============================================================================
 127 // Windows implementation of thread and related classes
 128 // ============================================================================
 129
 130 // ----------------------------------------------------------------------------
 131 // wxCriticalSection
 132 // ----------------------------------------------------------------------------
 133
 134 wxCriticalSection::wxCriticalSection()
 135 {
 136     wxCOMPILE_TIME_ASSERT( sizeof(CRITICAL_SECTION) <= sizeof(wxCritSectBuffer),
 137                            wxCriticalSectionBufferTooSmall );
 138
 139     ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
 140 }
 141
 142 wxCriticalSection::~wxCriticalSection()
 143 {
 144     ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
 145 }
 146
 147 void wxCriticalSection::Enter()
 148 {
 149     ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
 150 }
 151
 152 void wxCriticalSection::Leave()
 153 {
 154     ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
 155 }
 156
 157 // ----------------------------------------------------------------------------
 158 // wxMutex
 159 // ----------------------------------------------------------------------------
 160
 161 class wxMutexInternal
 162 {
 163 public:
 164     wxMutexInternal(wxMutexType mutexType);
 165     ~wxMutexInternal();
 166
 167     bool IsOk() const { return m_mutex != NULL; }
 168
 169     wxMutexError Lock() { return LockTimeout(INFINITE); }
 170     wxMutexError TryLock() { return LockTimeout(0); }
 171     wxMutexError Unlock();
 172
 173 private:
 174     wxMutexError LockTimeout(DWORD milliseconds);
 175
 176     HANDLE m_mutex;
 177 };
 178
 179 // all mutexes are recursive under Win32 so we don't use mutexType
 180 wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
 181 {
 182     // create a nameless (hence intra process and always private) mutex
 183     m_mutex = ::CreateMutex
 184                 (
 185                     NULL,       // default secutiry attributes
 186                     FALSE,      // not initially locked
 187                     NULL        // no name
 188                 );
 189
 190     if ( !m_mutex )
 191     {
 192         wxLogLastError(_T("CreateMutex()"));
 193     }
 194 }
 195
 196 wxMutexInternal::~wxMutexInternal()
 197 {
 198     if ( m_mutex )
 199     {
 200         if ( !::CloseHandle(m_mutex) )
 201         {
 202             wxLogLastError(_T("CloseHandle(mutex)"));
 203         }
 204     }
 205 }
 206
 207 wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
 208 {
 209     DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
 210     if ( rc == WAIT_ABANDONED )
 211     {
 212         // the previous caller died without releasing the mutex, but now we can
 213         // really lock it
 214         wxLogDebug(_T("WaitForSingleObject() returned WAIT_ABANDONED"));
 215
 216         // use 0 timeout, normally we should always get it
 217         rc = ::WaitForSingleObject(m_mutex, 0);
 218     }
 219
 220     switch ( rc )
 221     {
 222         case WAIT_OBJECT_0:
 223             // ok
 224             break;
 225
 226         case WAIT_TIMEOUT:
 227             return wxMUTEX_BUSY;
 228
 229         case WAIT_ABANDONED:        // checked for above
 230         default:
 231             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 232             // fall through
 233
 234         case WAIT_FAILED:
 235             wxLogLastError(_T("WaitForSingleObject(mutex)"));
 236             return wxMUTEX_MISC_ERROR;
 237     }
 238
 239     return wxMUTEX_NO_ERROR;
 240 }
 241
 242 wxMutexError wxMutexInternal::Unlock()
 243 {
 244     if ( !::ReleaseMutex(m_mutex) )
 245     {
 246         wxLogLastError(_("ReleaseMutex()"));
 247
 248         return wxMUTEX_MISC_ERROR;
 249     }
 250
 251     return wxMUTEX_NO_ERROR;
 252 }
 253
 254 // --------------------------------------------------------------------------
 255 // wxSemaphore
 256 // --------------------------------------------------------------------------
 257
 258 // a trivial wrapper around Win32 semaphore
 259 class wxSemaphoreInternal
 260 {
 261 public:
 262     wxSemaphoreInternal(int initialcount, int maxcount);
 263     ~wxSemaphoreInternal();
 264
 265     bool IsOk() const { return m_semaphore != NULL; }
 266
 267     wxSemaError Wait() { return WaitTimeout(INFINITE); }
 268     wxSemaError TryWait() { return WaitTimeout(0); }
 269     wxSemaError WaitTimeout(unsigned long milliseconds);
 270
 271     wxSemaError Post();
 272
 273 private:
 274     HANDLE m_semaphore;
 275 };
 276
 277 wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
 278 {
 279     if ( maxcount == 0 )
 280     {
 281         // make it practically infinite
 282         maxcount = INT_MAX;
 283     }
 284
 285     m_semaphore = ::CreateSemaphore
 286                     (
 287                         NULL,           // default security attributes
 288                         initialcount,
 289                         maxcount,
 290                         NULL            // no name
 291                     );
 292
 293     if ( !m_semaphore )
 294     {
 295         wxLogLastError(_T("CreateSemaphore()"));
 296     }
 297 }
 298
 299 wxSemaphoreInternal::~wxSemaphoreInternal()
 300 {
 301     if ( m_semaphore )
 302     {
 303         if ( !::CloseHandle(m_semaphore) )
 304         {
 305             wxLogLastError(_T("CloseHandle(semaphore)"));
 306         }
 307     }
 308 }
 309
 310 wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long milliseconds)
 311 {
 312     DWORD rc = ::WaitForSingleObject( m_semaphore, milliseconds );
 313
 314     switch ( rc )
 315     {
 316         case WAIT_OBJECT_0:
 317            return wxSEMA_NO_ERROR;
 318
 319         case WAIT_TIMEOUT:
 320            return wxSEMA_BUSY;
 321
 322         default:
 323             wxLogLastError(_T("WaitForSingleObject(semaphore)"));
 324     }
 325
 326     return wxSEMA_MISC_ERROR;
 327 }
 328
 329 wxSemaError wxSemaphoreInternal::Post()
 330 {
 331     if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
 332     {
 333         wxLogLastError(_T("ReleaseSemaphore"));
 334
 335         return wxSEMA_MISC_ERROR;
 336     }
 337
 338     return wxSEMA_NO_ERROR;
 339 }
 340
 341 // --------------------------------------------------------------------------
 342 // wxCondition
 343 // --------------------------------------------------------------------------
 344
 345 // Win32 doesn't have explicit support for the POSIX condition variables and
 346 // the Win32 events have quite different semantics, so we reimplement the
 347 // conditions from scratch using the mutexes and semaphores
 348 class wxConditionInternal
 349 {
 350 public:
 351     wxConditionInternal(wxMutex& mutex);
 352
 353     bool IsOk() const { return m_mutex.IsOk() && m_semaphore.IsOk(); }
 354
 355     wxCondError Wait();
 356     wxCondError WaitTimeout(unsigned long milliseconds);
 357
 358     wxCondError Signal();
 359     wxCondError Broadcast();
 360
 361 private:
 362     // the number of threads currently waiting for this condition
 363     LONG m_numWaiters;
 364
 365     // the critical section protecting m_numWaiters
 366     wxCriticalSection m_csWaiters;
 367
 368     wxMutex& m_mutex;
 369     wxSemaphore m_semaphore;
 370 };
 371
 372 wxConditionInternal::wxConditionInternal(wxMutex& mutex)
 373                    : m_mutex(mutex)
 374 {
 375     // another thread can't access it until we return from ctor, so no need to
 376     // protect access to m_numWaiters here
 377     m_numWaiters = 0;
 378 }
 379
 380 wxCondError wxConditionInternal::Wait()
 381 {
 382     // increment the number of waiters
 383     ::InterlockedIncrement(&m_numWaiters);
 384
 385     m_mutex.Unlock();
 386
 387     // a potential race condition can occur here
 388     //
 389     // after a thread increments nwaiters, and unlocks the mutex and before the
 390     // semaphore.Wait() is called, if another thread can cause a signal to be
 391     // generated
 392     //
 393     // this race condition is handled by using a semaphore and incrementing the
 394     // semaphore only if 'nwaiters' is greater that zero since the semaphore,
 395     // can 'remember' signals the race condition will not occur
 396
 397     // wait ( if necessary ) and decrement semaphore
 398     wxSemaError err = m_semaphore.Wait();
 399     m_mutex.Lock();
 400
 401     return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 402 }
 403
 404 wxCondError wxConditionInternal::WaitTimeout(unsigned long milliseconds)
 405 {
 406     ::InterlockedIncrement(&m_numWaiters);
 407
 408     m_mutex.Unlock();
 409
 410     // a race condition can occur at this point in the code
 411     //
 412     // please see the comments in Wait(), for details
 413
 414     wxSemaError err = m_semaphore.WaitTimeout(milliseconds);
 415
 416     if ( err == wxSEMA_BUSY )
 417     {
 418         // another potential race condition exists here it is caused when a
 419         // 'waiting' thread timesout, and returns from WaitForSingleObject, but
 420         // has not yet decremented 'nwaiters'.
 421         //
 422         // at this point if another thread calls signal() then the semaphore
 423         // will be incremented, but the waiting thread will miss it.
 424         //
 425         // to handle this particular case, the waiting thread calls
 426         // WaitForSingleObject again with a timeout of 0, after locking
 427         // 'nwaiters_mutex'. this call does not block because of the zero
 428         // timeout, but will allow the waiting thread to catch the missed
 429         // signals.
 430         wxCriticalSectionLocker lock(m_csWaiters);
 431
 432         err = m_semaphore.WaitTimeout(0);
 433
 434         if ( err != wxSEMA_NO_ERROR )
 435         {
 436             m_numWaiters--;
 437         }
 438     }
 439
 440     m_mutex.Lock();
 441
 442     return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 443 }
 444
 445 wxCondError wxConditionInternal::Signal()
 446 {
 447     wxCriticalSectionLocker lock(m_csWaiters);
 448
 449     if ( m_numWaiters > 0 )
 450     {
 451         // increment the semaphore by 1
 452         if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
 453             return wxCOND_MISC_ERROR;
 454
 455         m_numWaiters--;
 456     }
 457
 458     return wxCOND_NO_ERROR;
 459 }
 460
 461 wxCondError wxConditionInternal::Broadcast()
 462 {
 463     wxCriticalSectionLocker lock(m_csWaiters);
 464
 465     while ( m_numWaiters > 0 )
 466     {
 467         if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
 468             return wxCOND_MISC_ERROR;
 469
 470         m_numWaiters--;
 471     }
 472
 473     return wxCOND_NO_ERROR;
 474 }
 475
 476 // ----------------------------------------------------------------------------
 477 // wxThread implementation
 478 // ----------------------------------------------------------------------------
 479
 480 // wxThreadInternal class
 481 // ----------------------
 482
 483 class wxThreadInternal
 484 {
 485 public:
 486     wxThreadInternal()
 487     {
 488         m_hThread = 0;
 489         m_state = STATE_NEW;
 490         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 491     }
 492
 493     ~wxThreadInternal()
 494     {
 495         Free();
 496     }
 497
 498     void Free()
 499     {
 500         if ( m_hThread )
 501         {
 502             if ( !::CloseHandle(m_hThread) )
 503             {
 504                 wxLogLastError(wxT("CloseHandle(thread)"));
 505             }
 506
 507             m_hThread = 0;
 508         }
 509     }
 510
 511     // create a new (suspended) thread (for the given thread object)
 512     bool Create(wxThread *thread, unsigned int stackSize);
 513
 514     // suspend/resume/terminate
 515     bool Suspend();
 516     bool Resume();
 517     void Cancel() { m_state = STATE_CANCELED; }
 518
 519     // thread state
 520     void SetState(wxThreadState state) { m_state = state; }
 521     wxThreadState GetState() const { return m_state; }
 522
 523     // thread priority
 524     void SetPriority(unsigned int priority);
 525     unsigned int GetPriority() const { return m_priority; }
 526
 527     // thread handle and id
 528     HANDLE GetHandle() const { return m_hThread; }
 529     DWORD  GetId() const { return m_tid; }
 530
 531     // thread function
 532     static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
 533
 534 private:
 535     HANDLE        m_hThread;    // handle of the thread
 536     wxThreadState m_state;      // state, see wxThreadState enum
 537     unsigned int  m_priority;   // thread priority in "wx" units
 538     DWORD         m_tid;        // thread id
 539 };
 540
 541 THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 542 {
 543     THREAD_RETVAL rc;
 544     bool wasCancelled;
 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     wxThread *thread = (wxThread *)param;
 549     if ( thread->m_internal->GetState() == STATE_EXITED )
 550     {
 551         rc = (THREAD_RETVAL)-1;
 552         wasCancelled = TRUE;
 553     }
 554     else // do run thread
 555     {
 556         // store the thread object in the TLS
 557         if ( !::TlsSetValue(gs_tlsThisThread, thread) )
 558         {
 559             wxLogSysError(_("Can not start thread: error writing TLS."));
 560
 561             return (DWORD)-1;
 562         }
 563
 564         rc = (THREAD_RETVAL)thread->Entry();
 565
 566         // enter m_critsect before changing the thread state
 567         thread->m_critsect.Enter();
 568         wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
 569         thread->m_internal->SetState(STATE_EXITED);
 570         thread->m_critsect.Leave();
 571     }
 572
 573     thread->OnExit();
 574
 575     // if the thread was cancelled (from Delete()), then its handle is still
 576     // needed there
 577     if ( thread->IsDetached() && !wasCancelled )
 578     {
 579         // auto delete
 580         delete thread;
 581     }
 582     //else: the joinable threads handle will be closed when Wait() is done
 583
 584     return rc;
 585 }
 586
 587 void wxThreadInternal::SetPriority(unsigned int priority)
 588 {
 589     m_priority = priority;
 590
 591     // translate wxWindows priority to the Windows one
 592     int win_priority;
 593     if (m_priority <= 20)
 594         win_priority = THREAD_PRIORITY_LOWEST;
 595     else if (m_priority <= 40)
 596         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 597     else if (m_priority <= 60)
 598         win_priority = THREAD_PRIORITY_NORMAL;
 599     else if (m_priority <= 80)
 600         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 601     else if (m_priority <= 100)
 602         win_priority = THREAD_PRIORITY_HIGHEST;
 603     else
 604     {
 605         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 606         win_priority = THREAD_PRIORITY_NORMAL;
 607     }
 608
 609     if ( !::SetThreadPriority(m_hThread, win_priority) )
 610     {
 611         wxLogSysError(_("Can't set thread priority"));
 612     }
 613 }
 614
 615 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 616 {
 617     // for compilers which have it, we should use C RTL function for thread
 618     // creation instead of Win32 API one because otherwise we will have memory
 619     // leaks if the thread uses C RTL (and most threads do)
 620 #ifdef wxUSE_BEGIN_THREAD
 621
 622     // Watcom is reported to not like 0 stack size (which means "use default"
 623     // for the other compilers and is also the default value for stackSize)
 624 #ifdef __WATCOMC__
 625     if ( !stackSize )
 626         stackSize = 10240;
 627 #endif // __WATCOMC__
 628
 629     m_hThread = (HANDLE)_beginthreadex
 630                         (
 631                           NULL,                             // default security
 632                           stackSize,
 633                           wxThreadInternal::WinThreadStart, // entry point
 634                           thread,
 635                           CREATE_SUSPENDED,
 636                           (unsigned int *)&m_tid
 637                         );
 638 #else // compiler doesn't have _beginthreadex
 639     m_hThread = ::CreateThread
 640                   (
 641                     NULL,                               // default security
 642                     stackSize,                          // stack size
 643                     wxThreadInternal::WinThreadStart,   // thread entry point
 644                     (LPVOID)thread,                     // parameter
 645                     CREATE_SUSPENDED,                   // flags
 646                     &m_tid                              // [out] thread id
 647                   );
 648 #endif // _beginthreadex/CreateThread
 649
 650     if ( m_hThread == NULL )
 651     {
 652         wxLogSysError(_("Can't create thread"));
 653
 654         return FALSE;
 655     }
 656
 657     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 658     {
 659         SetPriority(m_priority);
 660     }
 661
 662     return TRUE;
 663 }
 664
 665 bool wxThreadInternal::Suspend()
 666 {
 667     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 668     if ( nSuspendCount == (DWORD)-1 )
 669     {
 670         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 671
 672         return FALSE;
 673     }
 674
 675     m_state = STATE_PAUSED;
 676
 677     return TRUE;
 678 }
 679
 680 bool wxThreadInternal::Resume()
 681 {
 682     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 683     if ( nSuspendCount == (DWORD)-1 )
 684     {
 685         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 686
 687         return FALSE;
 688     }
 689
 690     // don't change the state from STATE_EXITED because it's special and means
 691     // we are going to terminate without running any user code - if we did it,
 692     // the codei n Delete() wouldn't work
 693     if ( m_state != STATE_EXITED )
 694     {
 695         m_state = STATE_RUNNING;
 696     }
 697
 698     return TRUE;
 699 }
 700
 701 // static functions
 702 // ----------------
 703
 704 wxThread *wxThread::This()
 705 {
 706     wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
 707
 708     // be careful, 0 may be a valid return value as well
 709     if ( !thread && (::GetLastError() != NO_ERROR) )
 710     {
 711         wxLogSysError(_("Couldn't get the current thread pointer"));
 712
 713         // return NULL...
 714     }
 715
 716     return thread;
 717 }
 718
 719 bool wxThread::IsMain()
 720 {
 721     return ::GetCurrentThreadId() == gs_idMainThread;
 722 }
 723
 724 #ifdef Yield
 725 #undef Yield
 726 #endif
 727
 728 void wxThread::Yield()
 729 {
 730     // 0 argument to Sleep() is special and means to just give away the rest of
 731     // our timeslice
 732     ::Sleep(0);
 733 }
 734
 735 void wxThread::Sleep(unsigned long milliseconds)
 736 {
 737     ::Sleep(milliseconds);
 738 }
 739
 740 int wxThread::GetCPUCount()
 741 {
 742     SYSTEM_INFO si;
 743     GetSystemInfo(&si);
 744
 745     return si.dwNumberOfProcessors;
 746 }
 747
 748 unsigned long wxThread::GetCurrentId()
 749 {
 750     return (unsigned long)::GetCurrentThreadId();
 751 }
 752
 753 bool wxThread::SetConcurrency(size_t level)
 754 {
 755     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 756
 757     // ok only for the default one
 758     if ( level == 0 )
 759         return 0;
 760
 761     // get system affinity mask first
 762     HANDLE hProcess = ::GetCurrentProcess();
 763     DWORD dwProcMask, dwSysMask;
 764     if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
 765     {
 766         wxLogLastError(_T("GetProcessAffinityMask"));
 767
 768         return FALSE;
 769     }
 770
 771     // how many CPUs have we got?
 772     if ( dwSysMask == 1 )
 773     {
 774         // don't bother with all this complicated stuff - on a single
 775         // processor system it doesn't make much sense anyhow
 776         return level == 1;
 777     }
 778
 779     // calculate the process mask: it's a bit vector with one bit per
 780     // processor; we want to schedule the process to run on first level
 781     // CPUs
 782     DWORD bit = 1;
 783     while ( bit )
 784     {
 785         if ( dwSysMask & bit )
 786         {
 787             // ok, we can set this bit
 788             dwProcMask |= bit;
 789
 790             // another process added
 791             if ( !--level )
 792             {
 793                 // and that's enough
 794                 break;
 795             }
 796         }
 797
 798         // next bit
 799         bit <<= 1;
 800     }
 801
 802     // could we set all bits?
 803     if ( level != 0 )
 804     {
 805         wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 806
 807         return FALSE;
 808     }
 809
 810     // set it: we can't link to SetProcessAffinityMask() because it doesn't
 811     // exist in Win9x, use RT binding instead
 812
 813     typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
 814
 815     // can use static var because we're always in the main thread here
 816     static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
 817
 818     if ( !pfnSetProcessAffinityMask )
 819     {
 820         HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
 821         if ( hModKernel )
 822         {
 823             pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
 824                 ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
 825         }
 826
 827         // we've discovered a MT version of Win9x!
 828         wxASSERT_MSG( pfnSetProcessAffinityMask,
 829                       _T("this system has several CPUs but no SetProcessAffinityMask function?") );
 830     }
 831
 832     if ( !pfnSetProcessAffinityMask )
 833     {
 834         // msg given above - do it only once
 835         return FALSE;
 836     }
 837
 838     if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
 839     {
 840         wxLogLastError(_T("SetProcessAffinityMask"));
 841
 842         return FALSE;
 843     }
 844
 845     return TRUE;
 846 }
 847
 848 // ctor and dtor
 849 // -------------
 850
 851 wxThread::wxThread(wxThreadKind kind)
 852 {
 853     m_internal = new wxThreadInternal();
 854
 855     m_isDetached = kind == wxTHREAD_DETACHED;
 856 }
 857
 858 wxThread::~wxThread()
 859 {
 860     delete m_internal;
 861 }
 862
 863 // create/start thread
 864 // -------------------
 865
 866 wxThreadError wxThread::Create(unsigned int stackSize)
 867 {
 868     wxCriticalSectionLocker lock(m_critsect);
 869
 870     if ( !m_internal->Create(this, stackSize) )
 871         return wxTHREAD_NO_RESOURCE;
 872
 873     return wxTHREAD_NO_ERROR;
 874 }
 875
 876 wxThreadError wxThread::Run()
 877 {
 878     wxCriticalSectionLocker lock(m_critsect);
 879
 880     if ( m_internal->GetState() != STATE_NEW )
 881     {
 882         // actually, it may be almost any state at all, not only STATE_RUNNING
 883         return wxTHREAD_RUNNING;
 884     }
 885
 886     // the thread has just been created and is still suspended - let it run
 887     return Resume();
 888 }
 889
 890 // suspend/resume thread
 891 // ---------------------
 892
 893 wxThreadError wxThread::Pause()
 894 {
 895     wxCriticalSectionLocker lock(m_critsect);
 896
 897     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 898 }
 899
 900 wxThreadError wxThread::Resume()
 901 {
 902     wxCriticalSectionLocker lock(m_critsect);
 903
 904     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 905 }
 906
 907 // stopping thread
 908 // ---------------
 909
 910 wxThread::ExitCode wxThread::Wait()
 911 {
 912     // although under Windows we can wait for any thread, it's an error to
 913     // wait for a detached one in wxWin API
 914     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
 915                  _T("can't wait for detached thread") );
 916
 917     ExitCode rc = (ExitCode)-1;
 918
 919     (void)Delete(&rc);
 920
 921     m_internal->Free();
 922
 923     return rc;
 924 }
 925
 926 wxThreadError wxThread::Delete(ExitCode *pRc)
 927 {
 928     ExitCode rc = 0;
 929
 930     // Delete() is always safe to call, so consider all possible states
 931
 932     // we might need to resume the thread, but we might also not need to cancel
 933     // it if it doesn't run yet
 934     bool shouldResume = FALSE,
 935          shouldCancel = TRUE,
 936          isRunning = FALSE;
 937
 938     // check if the thread already started to run
 939     {
 940         wxCriticalSectionLocker lock(m_critsect);
 941
 942         if ( m_internal->GetState() == STATE_NEW )
 943         {
 944             // WinThreadStart() will see it and terminate immediately, no need
 945             // to cancel the thread - but we still need to resume it to let it
 946             // run
 947             m_internal->SetState(STATE_EXITED);
 948
 949             Resume();   // it knows about STATE_EXITED special case
 950
 951             shouldCancel = FALSE;
 952             isRunning = TRUE;
 953
 954             // shouldResume is correctly set to FALSE here
 955         }
 956         else
 957         {
 958             shouldResume = IsPaused();
 959         }
 960     }
 961
 962     // resume the thread if it is paused
 963     if ( shouldResume )
 964         Resume();
 965
 966     HANDLE hThread = m_internal->GetHandle();
 967
 968     // does is still run?
 969     if ( isRunning || IsRunning() )
 970     {
 971         if ( IsMain() )
 972         {
 973             // set flag for wxIsWaitingForThread()
 974             gs_waitingForThread = TRUE;
 975         }
 976
 977         // ask the thread to terminate
 978         if ( shouldCancel )
 979         {
 980             wxCriticalSectionLocker lock(m_critsect);
 981
 982             m_internal->Cancel();
 983         }
 984
 985 #if wxUSE_GUI
 986         // we can't just wait for the thread to terminate because it might be
 987         // calling some GUI functions and so it will never terminate before we
 988         // process the Windows messages that result from these functions
 989         DWORD result = 0;       // suppress warnings from broken compilers
 990         do
 991         {
 992             if ( IsMain() )
 993             {
 994                 // give the thread we're waiting for chance to do the GUI call
 995                 // it might be in
 996                 if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 997                 {
 998                     wxMutexGuiLeave();
 999                 }
1000             }
1001
1002             result = ::MsgWaitForMultipleObjects
1003                      (
1004                        1,              // number of objects to wait for
1005                        &hThread,       // the objects
1006                        FALSE,          // don't wait for all objects
1007                        INFINITE,       // no timeout
1008                        QS_ALLINPUT |   // return as soon as there are any events
1009                        QS_ALLPOSTMESSAGE
1010                      );
1011
1012             switch ( result )
1013             {
1014                 case 0xFFFFFFFF:
1015                     // error
1016                     wxLogSysError(_("Can not wait for thread termination"));
1017                     Kill();
1018                     return wxTHREAD_KILLED;
1019
1020                 case WAIT_OBJECT_0:
1021                     // thread we're waiting for terminated
1022                     break;
1023
1024                 case WAIT_OBJECT_0 + 1:
1025                     // new message arrived, process it
1026                     if ( !wxTheApp->DoMessage() )
1027                     {
1028                         // WM_QUIT received: kill the thread
1029                         Kill();
1030
1031                         return wxTHREAD_KILLED;
1032                     }
1033                     break;
1034
1035                 default:
1036                     wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
1037             }
1038         } while ( result != WAIT_OBJECT_0 );
1039 #else // !wxUSE_GUI
1040         // simply wait for the thread to terminate
1041         //
1042         // OTOH, even console apps create windows (in wxExecute, for WinSock
1043         // &c), so may be use MsgWaitForMultipleObject() too here?
1044         if ( WaitForSingleObject(hThread, INFINITE) != WAIT_OBJECT_0 )
1045         {
1046             wxFAIL_MSG(wxT("unexpected result of WaitForSingleObject"));
1047         }
1048 #endif // wxUSE_GUI/!wxUSE_GUI
1049
1050         if ( IsMain() )
1051         {
1052             gs_waitingForThread = FALSE;
1053         }
1054     }
1055
1056     // although the thread might be already in the EXITED state it might not
1057     // have terminated yet and so we are not sure that it has actually
1058     // terminated if the "if" above hadn't been taken
1059     do
1060     {
1061         if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
1062         {
1063             wxLogLastError(wxT("GetExitCodeThread"));
1064
1065             rc = (ExitCode)-1;
1066         }
1067     } while ( (DWORD)rc == STILL_ACTIVE );
1068
1069     if ( IsDetached() )
1070     {
1071         // if the thread exits normally, this is done in WinThreadStart, but in
1072         // this case it would have been too early because
1073         // MsgWaitForMultipleObject() would fail if the thread handle was
1074         // closed while we were waiting on it, so we must do it here
1075         delete this;
1076     }
1077
1078     if ( pRc )
1079         *pRc = rc;
1080
1081     return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
1082 }
1083
1084 wxThreadError wxThread::Kill()
1085 {
1086     if ( !IsRunning() )
1087         return wxTHREAD_NOT_RUNNING;
1088
1089     if ( !::TerminateThread(m_internal->GetHandle(), (DWORD)-1) )
1090     {
1091         wxLogSysError(_("Couldn't terminate thread"));
1092
1093         return wxTHREAD_MISC_ERROR;
1094     }
1095
1096     m_internal->Free();
1097
1098     if ( IsDetached() )
1099     {
1100         delete this;
1101     }
1102
1103     return wxTHREAD_NO_ERROR;
1104 }
1105
1106 void wxThread::Exit(ExitCode status)
1107 {
1108     m_internal->Free();
1109
1110     if ( IsDetached() )
1111     {
1112         delete this;
1113     }
1114
1115 #ifdef wxUSE_BEGIN_THREAD
1116     _endthreadex((unsigned)status);
1117 #else // !VC++
1118     ::ExitThread((DWORD)status);
1119 #endif // VC++/!VC++
1120
1121     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
1122 }
1123
1124 // priority setting
1125 // ----------------
1126
1127 void wxThread::SetPriority(unsigned int prio)
1128 {
1129     wxCriticalSectionLocker lock(m_critsect);
1130
1131     m_internal->SetPriority(prio);
1132 }
1133
1134 unsigned int wxThread::GetPriority() const
1135 {
1136     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1137
1138     return m_internal->GetPriority();
1139 }
1140
1141 unsigned long wxThread::GetId() const
1142 {
1143     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1144
1145     return (unsigned long)m_internal->GetId();
1146 }
1147
1148 bool wxThread::IsRunning() const
1149 {
1150     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1151
1152     return m_internal->GetState() == STATE_RUNNING;
1153 }
1154
1155 bool wxThread::IsAlive() const
1156 {
1157     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1158
1159     return (m_internal->GetState() == STATE_RUNNING) ||
1160            (m_internal->GetState() == STATE_PAUSED);
1161 }
1162
1163 bool wxThread::IsPaused() const
1164 {
1165     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1166
1167     return m_internal->GetState() == STATE_PAUSED;
1168 }
1169
1170 bool wxThread::TestDestroy()
1171 {
1172     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
1173
1174     return m_internal->GetState() == STATE_CANCELED;
1175 }
1176
1177 // ----------------------------------------------------------------------------
1178 // Automatic initialization for thread module
1179 // ----------------------------------------------------------------------------
1180
1181 class wxThreadModule : public wxModule
1182 {
1183 public:
1184     virtual bool OnInit();
1185     virtual void OnExit();
1186
1187 private:
1188     DECLARE_DYNAMIC_CLASS(wxThreadModule)
1189 };
1190
1191 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
1192
1193 bool wxThreadModule::OnInit()
1194 {
1195     // allocate TLS index for storing the pointer to the current thread
1196     gs_tlsThisThread = ::TlsAlloc();
1197     if ( gs_tlsThisThread == 0xFFFFFFFF )
1198     {
1199         // in normal circumstances it will only happen if all other
1200         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
1201         // words, this should never happen
1202         wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
1203
1204         return FALSE;
1205     }
1206
1207     // main thread doesn't have associated wxThread object, so store 0 in the
1208     // TLS instead
1209     if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
1210     {
1211         ::TlsFree(gs_tlsThisThread);
1212         gs_tlsThisThread = 0xFFFFFFFF;
1213
1214         wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
1215
1216         return FALSE;
1217     }
1218
1219     gs_critsectWaitingForGui = new wxCriticalSection();
1220
1221     gs_critsectGui = new wxCriticalSection();
1222     gs_critsectGui->Enter();
1223
1224     // no error return for GetCurrentThreadId()
1225     gs_idMainThread = ::GetCurrentThreadId();
1226
1227     return TRUE;
1228 }
1229
1230 void wxThreadModule::OnExit()
1231 {
1232     if ( !::TlsFree(gs_tlsThisThread) )
1233     {
1234         wxLogLastError(wxT("TlsFree failed."));
1235     }
1236
1237     if ( gs_critsectGui )
1238     {
1239         gs_critsectGui->Leave();
1240         delete gs_critsectGui;
1241         gs_critsectGui = NULL;
1242     }
1243
1244     delete gs_critsectWaitingForGui;
1245     gs_critsectWaitingForGui = NULL;
1246 }
1247
1248 // ----------------------------------------------------------------------------
1249 // under Windows, these functions are implemented using a critical section and
1250 // not a mutex, so the names are a bit confusing
1251 // ----------------------------------------------------------------------------
1252
1253 void WXDLLEXPORT wxMutexGuiEnter()
1254 {
1255     // this would dead lock everything...
1256     wxASSERT_MSG( !wxThread::IsMain(),
1257                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
1258
1259     // the order in which we enter the critical sections here is crucial!!
1260
1261     // set the flag telling to the main thread that we want to do some GUI
1262     {
1263         wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1264
1265         gs_nWaitingForGui++;
1266     }
1267
1268     wxWakeUpMainThread();
1269
1270     // now we may block here because the main thread will soon let us in
1271     // (during the next iteration of OnIdle())
1272     gs_critsectGui->Enter();
1273 }
1274
1275 void WXDLLEXPORT wxMutexGuiLeave()
1276 {
1277     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1278
1279     if ( wxThread::IsMain() )
1280     {
1281         gs_bGuiOwnedByMainThread = FALSE;
1282     }
1283     else
1284     {
1285         // decrement the number of threads waiting for GUI access now
1286         wxASSERT_MSG( gs_nWaitingForGui > 0,
1287                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1288
1289         gs_nWaitingForGui--;
1290
1291         wxWakeUpMainThread();
1292     }
1293
1294     gs_critsectGui->Leave();
1295 }
1296
1297 void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
1298 {
1299     wxASSERT_MSG( wxThread::IsMain(),
1300                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1301
1302     wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
1303
1304     if ( gs_nWaitingForGui == 0 )
1305     {
1306         // no threads are waiting for GUI - so we may acquire the lock without
1307         // any danger (but only if we don't already have it)
1308         if ( !wxGuiOwnedByMainThread() )
1309         {
1310             gs_critsectGui->Enter();
1311
1312             gs_bGuiOwnedByMainThread = TRUE;
1313         }
1314         //else: already have it, nothing to do
1315     }
1316     else
1317     {
1318         // some threads are waiting, release the GUI lock if we have it
1319         if ( wxGuiOwnedByMainThread() )
1320         {
1321             wxMutexGuiLeave();
1322         }
1323         //else: some other worker thread is doing GUI
1324     }
1325 }
1326
1327 bool WXDLLEXPORT wxGuiOwnedByMainThread()
1328 {
1329     return gs_bGuiOwnedByMainThread;
1330 }
1331
1332 // wake up the main thread if it's in ::GetMessage()
1333 void WXDLLEXPORT wxWakeUpMainThread()
1334 {
1335     // sending any message would do - hopefully WM_NULL is harmless enough
1336     if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
1337     {
1338         // should never happen
1339         wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
1340     }
1341 }
1342
1343 bool WXDLLEXPORT wxIsWaitingForThread()
1344 {
1345     return gs_waitingForThread;
1346 }
1347
1348 // ----------------------------------------------------------------------------
1349 // include common implementation code
1350 // ----------------------------------------------------------------------------
1351
1352 #include "wx/thrimpl.cpp"
1353
1354 #endif // wxUSE_THREADS
1355