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