src/unix/threadpsx.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        threadpsx.cpp
   3 // Purpose:     wxThread (Posix) Implementation
   4 // Author:      Original from Wolfram Gloger/Guilhem Lavaux
   5 // Modified by:
   6 // Created:     04/22/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Wolfram Gloger (1996, 1997)
   9 //                  Guilhem Lavaux (1998)
  10 //                  Vadim Zeitlin (1999)
  11 //                  Robert Roebling (1999)
  12 // Licence:     wxWindows licence
  13 /////////////////////////////////////////////////////////////////////////////
  14
  15 // ============================================================================
  16 // declaration
  17 // ============================================================================
  18
  19 // ----------------------------------------------------------------------------
  20 // headers
  21 // ----------------------------------------------------------------------------
  22
  23 #ifdef __GNUG__
  24     #pragma implementation "thread.h"
  25 #endif
  26
  27 #include "wx/thread.h"
  28
  29 #if !wxUSE_THREADS
  30     #error This file needs wxUSE_THREADS
  31 #endif
  32
  33 #include "wx/module.h"
  34 #include "wx/utils.h"
  35 #include "wx/log.h"
  36 #include "wx/intl.h"
  37 #include "wx/dynarray.h"
  38
  39 #include <stdio.h>
  40 #include <unistd.h>
  41 #include <pthread.h>
  42 #include <errno.h>
  43 #include <time.h>
  44
  45 #ifdef HAVE_SCHED_H
  46     #include <sched.h>
  47 #endif
  48
  49 // ----------------------------------------------------------------------------
  50 // constants
  51 // ----------------------------------------------------------------------------
  52
  53 enum thread_state
  54 {
  55     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  56     STATE_RUNNING,
  57     STATE_PAUSED,
  58     STATE_CANCELED,
  59     STATE_EXITED
  60 };
  61
  62 WX_DEFINE_ARRAY(wxThread *, wxArrayThread);
  63
  64 // -----------------------------------------------------------------------------
  65 // global data
  66 // -----------------------------------------------------------------------------
  67
  68 // we keep the list of all threads created by the application to be able to
  69 // terminate them on exit if there are some left - otherwise the process would
  70 // be left in memory
  71 static wxArrayThread gs_allThreads;
  72
  73 // the id of the main thread
  74 static pthread_t gs_tidMain;
  75
  76 // the key for the pointer to the associated wxThread object
  77 static pthread_key_t gs_keySelf;
  78
  79 // this mutex must be acquired before any call to a GUI function
  80 static wxMutex *gs_mutexGui;
  81
  82 // ============================================================================
  83 // implementation
  84 // ============================================================================
  85
  86 //--------------------------------------------------------------------
  87 // wxMutex (Posix implementation)
  88 //--------------------------------------------------------------------
  89
  90 class wxMutexInternal
  91 {
  92 public:
  93     pthread_mutex_t p_mutex;
  94 };
  95
  96 wxMutex::wxMutex()
  97 {
  98     p_internal = new wxMutexInternal;
  99     pthread_mutex_init( &(p_internal->p_mutex), (const pthread_mutexattr_t*) NULL );
 100     m_locked = 0;
 101 }
 102
 103 wxMutex::~wxMutex()
 104 {
 105     if (m_locked > 0)
 106         wxLogDebug("Freeing a locked mutex (%d locks)", m_locked);
 107
 108     pthread_mutex_destroy( &(p_internal->p_mutex) );
 109     delete p_internal;
 110 }
 111
 112 wxMutexError wxMutex::Lock()
 113 {
 114     int err = pthread_mutex_lock( &(p_internal->p_mutex) );
 115     if (err == EDEADLK)
 116     {
 117         wxLogDebug("Locking this mutex would lead to deadlock!");
 118
 119         return wxMUTEX_DEAD_LOCK;
 120     }
 121
 122     m_locked++;
 123
 124     return wxMUTEX_NO_ERROR;
 125 }
 126
 127 wxMutexError wxMutex::TryLock()
 128 {
 129     if (m_locked)
 130     {
 131         return wxMUTEX_BUSY;
 132     }
 133
 134     int err = pthread_mutex_trylock( &(p_internal->p_mutex) );
 135     switch (err)
 136     {
 137         case EBUSY: return wxMUTEX_BUSY;
 138     }
 139
 140     m_locked++;
 141
 142     return wxMUTEX_NO_ERROR;
 143 }
 144
 145 wxMutexError wxMutex::Unlock()
 146 {
 147     if (m_locked > 0)
 148     {
 149         m_locked--;
 150     }
 151     else
 152     {
 153         wxLogDebug("Unlocking not locked mutex.");
 154
 155         return wxMUTEX_UNLOCKED;
 156     }
 157
 158     pthread_mutex_unlock( &(p_internal->p_mutex) );
 159
 160     return wxMUTEX_NO_ERROR;
 161 }
 162
 163 //--------------------------------------------------------------------
 164 // wxCondition (Posix implementation)
 165 //--------------------------------------------------------------------
 166
 167 class wxConditionInternal
 168 {
 169 public:
 170   pthread_cond_t p_condition;
 171 };
 172
 173 wxCondition::wxCondition()
 174 {
 175     p_internal = new wxConditionInternal;
 176     pthread_cond_init( &(p_internal->p_condition), (const pthread_condattr_t *) NULL );
 177 }
 178
 179 wxCondition::~wxCondition()
 180 {
 181     pthread_cond_destroy( &(p_internal->p_condition) );
 182
 183     delete p_internal;
 184 }
 185
 186 void wxCondition::Wait(wxMutex& mutex)
 187 {
 188     pthread_cond_wait( &(p_internal->p_condition), &(mutex.p_internal->p_mutex) );
 189 }
 190
 191 bool wxCondition::Wait(wxMutex& mutex, unsigned long sec, unsigned long nsec)
 192 {
 193     struct timespec tspec;
 194
 195     tspec.tv_sec = time(0L)+sec;
 196     tspec.tv_nsec = nsec;
 197     return (pthread_cond_timedwait(&(p_internal->p_condition), &(mutex.p_internal->p_mutex), &tspec) != ETIMEDOUT);
 198 }
 199
 200 void wxCondition::Signal()
 201 {
 202     pthread_cond_signal( &(p_internal->p_condition) );
 203 }
 204
 205 void wxCondition::Broadcast()
 206 {
 207     pthread_cond_broadcast( &(p_internal->p_condition) );
 208 }
 209
 210 //--------------------------------------------------------------------
 211 // wxThread (Posix implementation)
 212 //--------------------------------------------------------------------
 213
 214 class wxThreadInternal
 215 {
 216 public:
 217     wxThreadInternal();
 218     ~wxThreadInternal();
 219
 220     // thread entry function
 221     static void *PthreadStart(void *ptr);
 222
 223     // thread actions
 224         // start the thread
 225     wxThreadError Run();
 226         // ask the thread to terminate
 227     void Cancel();
 228         // wake up threads waiting for our termination
 229     void SignalExit();
 230         // go to sleep until Resume() is called
 231     void Pause();
 232         // resume the thread
 233     void Resume();
 234
 235     // accessors
 236         // priority
 237     int GetPriority() const { return m_prio; }
 238     void SetPriority(int prio) { m_prio = prio; }
 239         // state
 240     thread_state GetState() const { return m_state; }
 241     void SetState(thread_state state) { m_state = state; }
 242         // id
 243     pthread_t GetId() const { return thread_id; }
 244         // "cancelled" flag
 245     bool WasCancelled() const { return m_cancelled; }
 246
 247 //private: -- should be!
 248     pthread_t thread_id;
 249
 250 private:
 251     thread_state m_state;    // see thread_state enum
 252     int          m_prio;     // in wxWindows units: from 0 to 100
 253
 254     // set when the thread should terminate
 255     bool m_cancelled;
 256
 257     // this (mutex, cond) pair is used to synchronize the main thread and this
 258     // thread in several situations:
 259     //  1. The thread function blocks until condition is signaled by Run() when
 260     //     it's initially created - this allows create thread in "suspended"
 261     //     state
 262     //  2. The Delete() function blocks until the condition is signaled when the
 263     //     thread exits.
 264     wxMutex     m_mutex;
 265     wxCondition m_cond;
 266
 267     // another (mutex, cond) pair for Pause()/Resume() usage
 268     //
 269     // VZ: it's possible that we might reuse the mutex and condition from above
 270     //     for this too, but as I'm not at all sure that it won't create subtle
 271     //     problems with race conditions between, say, Pause() and Delete() I
 272     //     prefer this may be a bit less efficient but much safer solution
 273     wxMutex     m_mutexSuspend;
 274     wxCondition m_condSuspend;
 275 };
 276
 277 void *wxThreadInternal::PthreadStart(void *ptr)
 278 {
 279     wxThread *thread = (wxThread *)ptr;
 280     wxThreadInternal *pthread = thread->p_internal;
 281
 282     if ( pthread_setspecific(gs_keySelf, thread) != 0 )
 283     {
 284         wxLogError(_("Can not start thread: error writing TLS."));
 285
 286         return (void *)-1;
 287     }
 288
 289     // wait for the condition to be signaled from Run()
 290     // mutex state: currently locked by the thread which created us
 291     pthread->m_cond.Wait(pthread->m_mutex);
 292
 293     // mutex state: locked again on exit of Wait()
 294
 295     // call the main entry
 296     void* status = thread->Entry();
 297
 298     // terminate the thread
 299     thread->Exit(status);
 300
 301     wxFAIL_MSG("wxThread::Exit() can't return.");
 302
 303     return NULL;
 304 }
 305
 306 wxThreadInternal::wxThreadInternal()
 307 {
 308     m_state = STATE_NEW;
 309     m_cancelled = FALSE;
 310
 311     // this mutex is locked during almost all thread lifetime - it will only be
 312     // unlocked in the very end
 313     m_mutex.Lock();
 314
 315     // this mutex is used in Pause()/Resume() and is also locked all the time
 316     // unless the thread is paused
 317     m_mutexSuspend.Lock();
 318 }
 319
 320 wxThreadInternal::~wxThreadInternal()
 321 {
 322     m_mutexSuspend.Unlock();
 323
 324     // note that m_mutex will be unlocked by the thread which waits for our
 325     // termination
 326 }
 327
 328 wxThreadError wxThreadInternal::Run()
 329 {
 330     wxCHECK_MSG( GetState() == STATE_NEW, wxTHREAD_RUNNING,
 331                  "thread may only be started once after successful Create()" );
 332
 333     // the mutex was locked on Create(), so we will be able to lock it again
 334     // only when the thread really starts executing and enters the wait -
 335     // otherwise we might signal the condition before anybody is waiting for it
 336     wxMutexLocker lock(m_mutex);
 337     m_cond.Signal();
 338
 339     m_state = STATE_RUNNING;
 340
 341     return wxTHREAD_NO_ERROR;
 342
 343     // now the mutex is unlocked back - but just to allow Wait() function to
 344     // terminate by relocking it, so the net result is that the worker thread
 345     // starts executing and the mutex is still locked
 346 }
 347
 348 void wxThreadInternal::Cancel()
 349 {
 350     // if the thread we're waiting for is waiting for the GUI mutex, we will
 351     // deadlock so make sure we release it temporarily
 352     if ( wxThread::IsMain() )
 353         wxMutexGuiLeave();
 354
 355     // nobody ever writes this variable so it's safe to not use any
 356     // synchronization here
 357     m_cancelled = TRUE;
 358
 359     // entering Wait() releases the mutex thus allowing SignalExit() to acquire
 360     // it and to signal us its termination
 361     m_cond.Wait(m_mutex);
 362
 363     // mutex is still in the locked state - relocked on exit from Wait(), so
 364     // unlock it - we don't need it any more, the thread has already terminated
 365     m_mutex.Unlock();
 366
 367     // reacquire GUI mutex
 368     if ( wxThread::IsMain() )
 369         wxMutexGuiEnter();
 370 }
 371
 372 void wxThreadInternal::SignalExit()
 373 {
 374     // as mutex is currently locked, this will block until some other thread
 375     // (normally the same which created this one) unlocks it by entering Wait()
 376     m_mutex.Lock();
 377
 378     // wake up all the threads waiting for our termination
 379     m_cond.Broadcast();
 380
 381     // after this call mutex will be finally unlocked
 382     m_mutex.Unlock();
 383 }
 384
 385 void wxThreadInternal::Pause()
 386 {
 387     wxCHECK_RET( m_state == STATE_PAUSED,
 388                  "thread must first be paused with wxThread::Pause()." );
 389
 390     // wait until the condition is signaled from Resume()
 391     m_condSuspend.Wait(m_mutexSuspend);
 392 }
 393
 394 void wxThreadInternal::Resume()
 395 {
 396     wxCHECK_RET( m_state == STATE_PAUSED,
 397                  "can't resume thread which is not suspended." );
 398
 399     // we will be able to lock this mutex only when Pause() starts waiting
 400     wxMutexLocker lock(m_mutexSuspend);
 401     m_condSuspend.Signal();
 402
 403     SetState(STATE_RUNNING);
 404 }
 405
 406 // -----------------------------------------------------------------------------
 407 // static functions
 408 // -----------------------------------------------------------------------------
 409
 410 wxThread *wxThread::This()
 411 {
 412     return (wxThread *)pthread_getspecific(gs_keySelf);
 413 }
 414
 415 bool wxThread::IsMain()
 416 {
 417     return (bool)pthread_equal(pthread_self(), gs_tidMain);
 418 }
 419
 420 void wxThread::Yield()
 421 {
 422     sched_yield();
 423 }
 424
 425 void wxThread::Sleep(unsigned long milliseconds)
 426 {
 427     wxUsleep(milliseconds);
 428 }
 429
 430 // -----------------------------------------------------------------------------
 431 // creating thread
 432 // -----------------------------------------------------------------------------
 433
 434 wxThread::wxThread()
 435 {
 436     // add this thread to the global list of all threads
 437     gs_allThreads.Add(this);
 438
 439     p_internal = new wxThreadInternal();
 440 }
 441
 442 wxThreadError wxThread::Create()
 443 {
 444     if (p_internal->GetState() != STATE_NEW)
 445         return wxTHREAD_RUNNING;
 446
 447     // set up the thread attribute: right now, we only set thread priority
 448     pthread_attr_t attr;
 449     pthread_attr_init(&attr);
 450
 451     int prio;
 452     if ( pthread_attr_getschedpolicy(&attr, &prio) != 0 )
 453     {
 454         wxLogError(_("Can not retrieve thread scheduling policy."));
 455     }
 456
 457 #ifdef HAVE_THREAD_PRIORITY_FUNCTIONS
 458     int min_prio = sched_get_priority_min(prio),
 459         max_prio = sched_get_priority_max(prio);
 460
 461     if ( min_prio == -1 || max_prio == -1 )
 462     {
 463         wxLogError(_("Can not get priority range for scheduling policy %d."),
 464                    prio);
 465     }
 466     else
 467     {
 468         struct sched_param sp;
 469         pthread_attr_getschedparam(&attr, &sp);
 470         sp.sched_priority = min_prio +
 471                            (p_internal->GetPriority()*(max_prio-min_prio))/100;
 472         pthread_attr_setschedparam(&attr, &sp);
 473     }
 474 #endif // HAVE_THREAD_PRIORITY_FUNCTIONS
 475
 476     // create the new OS thread object
 477     int rc = pthread_create(&p_internal->thread_id, &attr,
 478                             wxThreadInternal::PthreadStart, (void *)this);
 479     pthread_attr_destroy(&attr);
 480
 481     if ( rc != 0 )
 482     {
 483         p_internal->SetState(STATE_EXITED);
 484         return wxTHREAD_NO_RESOURCE;
 485     }
 486
 487     return wxTHREAD_NO_ERROR;
 488 }
 489
 490 wxThreadError wxThread::Run()
 491 {
 492     return p_internal->Run();
 493 }
 494
 495 // -----------------------------------------------------------------------------
 496 // misc accessors
 497 // -----------------------------------------------------------------------------
 498
 499 void wxThread::SetPriority(unsigned int prio)
 500 {
 501     wxCHECK_RET( ((int)WXTHREAD_MIN_PRIORITY <= (int)prio) &&
 502                  ((int)prio <= (int)WXTHREAD_MAX_PRIORITY),
 503                  "invalid thread priority" );
 504
 505     wxCriticalSectionLocker lock(m_critsect);
 506
 507     switch ( p_internal->GetState() )
 508     {
 509         case STATE_NEW:
 510             // thread not yet started, priority will be set when it is
 511             p_internal->SetPriority(prio);
 512             break;
 513
 514         case STATE_RUNNING:
 515         case STATE_PAUSED:
 516 #ifdef HAVE_THREAD_PRIORITY_FUNCTIONS
 517             {
 518                 struct sched_param sparam;
 519                 sparam.sched_priority = prio;
 520
 521                 if ( pthread_setschedparam(p_internal->GetId(),
 522                                            SCHED_OTHER, &sparam) != 0 )
 523                 {
 524                     wxLogError(_("Failed to set thread priority %d."), prio);
 525                 }
 526             }
 527 #endif // HAVE_THREAD_PRIORITY_FUNCTIONS
 528             break;
 529
 530         case STATE_EXITED:
 531         default:
 532             wxFAIL_MSG("impossible to set thread priority in this state");
 533     }
 534 }
 535
 536 unsigned int wxThread::GetPriority() const
 537 {
 538     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 539
 540     return p_internal->GetPriority();
 541 }
 542
 543 unsigned long wxThread::GetID() const
 544 {
 545     return (unsigned long)p_internal->thread_id;
 546 }
 547
 548 // -----------------------------------------------------------------------------
 549 // pause/resume
 550 // -----------------------------------------------------------------------------
 551
 552 wxThreadError wxThread::Pause()
 553 {
 554     wxCriticalSectionLocker lock(m_critsect);
 555
 556     if ( p_internal->GetState() != STATE_RUNNING )
 557     {
 558         wxLogDebug("Can't pause thread which is not running.");
 559
 560         return wxTHREAD_NOT_RUNNING;
 561     }
 562
 563     p_internal->SetState(STATE_PAUSED);
 564
 565     return wxTHREAD_NO_ERROR;
 566 }
 567
 568 wxThreadError wxThread::Resume()
 569 {
 570     wxCriticalSectionLocker lock(m_critsect);
 571
 572     if ( p_internal->GetState() == STATE_PAUSED )
 573     {
 574         p_internal->Resume();
 575
 576         return wxTHREAD_NO_ERROR;
 577     }
 578     else
 579     {
 580         wxLogDebug("Attempt to resume a thread which is not paused.");
 581
 582         return wxTHREAD_MISC_ERROR;
 583     }
 584 }
 585
 586 // -----------------------------------------------------------------------------
 587 // exiting thread
 588 // -----------------------------------------------------------------------------
 589
 590 wxThread::ExitCode wxThread::Delete()
 591 {
 592     m_critsect.Enter();
 593     thread_state state = p_internal->GetState();
 594     m_critsect.Leave();
 595
 596     switch ( state )
 597     {
 598         case STATE_NEW:
 599         case STATE_EXITED:
 600             // nothing to do
 601             break;
 602
 603         case STATE_PAUSED:
 604             // resume the thread first
 605             Resume();
 606
 607             // fall through
 608
 609         default:
 610             // set the flag telling to the thread to stop and wait
 611             p_internal->Cancel();
 612     }
 613
 614     return NULL;
 615 }
 616
 617 wxThreadError wxThread::Kill()
 618 {
 619     switch ( p_internal->GetState() )
 620     {
 621         case STATE_NEW:
 622         case STATE_EXITED:
 623             return wxTHREAD_NOT_RUNNING;
 624
 625         default:
 626 #ifdef HAVE_PTHREAD_CANCEL
 627             if ( pthread_cancel(p_internal->GetId()) != 0 )
 628 #endif
 629             {
 630                 wxLogError(_("Failed to terminate a thread."));
 631
 632                 return wxTHREAD_MISC_ERROR;
 633             }
 634
 635             return wxTHREAD_NO_ERROR;
 636     }
 637 }
 638
 639 void wxThread::Exit(void *status)
 640 {
 641     // first call user-level clean up code
 642     OnExit();
 643
 644     // next wake up the threads waiting for us (OTOH, this function won't return
 645     // until someone waited for us!)
 646     p_internal->SignalExit();
 647
 648     p_internal->SetState(STATE_EXITED);
 649
 650     // delete both C++ thread object and terminate the OS thread object
 651     delete this;
 652     pthread_exit(status);
 653 }
 654
 655 // also test whether we were paused
 656 bool wxThread::TestDestroy()
 657 {
 658     wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
 659
 660     if ( p_internal->GetState() == STATE_PAUSED )
 661     {
 662         // leave the crit section or the other threads will stop too if they try
 663         // to call any of (seemingly harmless) IsXXX() functions while we sleep
 664         m_critsect.Leave();
 665
 666         p_internal->Pause();
 667
 668         // enter it back before it's finally left in lock object dtor
 669         m_critsect.Enter();
 670     }
 671
 672     return p_internal->WasCancelled();
 673 }
 674
 675 wxThread::~wxThread()
 676 {
 677     // remove this thread from the global array
 678     gs_allThreads.Remove(this);
 679 }
 680
 681 // -----------------------------------------------------------------------------
 682 // state tests
 683 // -----------------------------------------------------------------------------
 684
 685 bool wxThread::IsRunning() const
 686 {
 687     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 688
 689     return p_internal->GetState() == STATE_RUNNING;
 690 }
 691
 692 bool wxThread::IsAlive() const
 693 {
 694     wxCriticalSectionLocker lock((wxCriticalSection&)m_critsect);
 695
 696     switch ( p_internal->GetState() )
 697     {
 698         case STATE_RUNNING:
 699         case STATE_PAUSED:
 700             return TRUE;
 701
 702         default:
 703             return FALSE;
 704     }
 705 }
 706
 707 //--------------------------------------------------------------------
 708 // wxThreadModule
 709 //--------------------------------------------------------------------
 710
 711 class wxThreadModule : public wxModule
 712 {
 713 public:
 714     virtual bool OnInit();
 715     virtual void OnExit();
 716
 717 private:
 718     DECLARE_DYNAMIC_CLASS(wxThreadModule)
 719 };
 720
 721 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
 722
 723 bool wxThreadModule::OnInit()
 724 {
 725     if ( pthread_key_create(&gs_keySelf, NULL /* dtor function */) != 0 )
 726     {
 727         wxLogError(_("Thread module initialization failed: "
 728                      "failed to create pthread key."));
 729
 730         return FALSE;
 731     }
 732
 733     gs_mutexGui = new wxMutex();
 734
 735     //wxThreadGuiInit();
 736
 737     gs_tidMain = pthread_self();
 738     gs_mutexGui->Lock();
 739
 740     return TRUE;
 741 }
 742
 743 void wxThreadModule::OnExit()
 744 {
 745     wxASSERT_MSG( wxThread::IsMain(), "only main thread can be here" );
 746
 747     // terminate any threads left
 748     size_t count = gs_allThreads.GetCount();
 749     if ( count != 0u )
 750         wxLogDebug("Some threads were not terminated by the application.");
 751
 752     for ( size_t n = 0u; n < count; n++ )
 753     {
 754         gs_allThreads[n]->Delete();
 755     }
 756
 757     // destroy GUI mutex
 758     gs_mutexGui->Unlock();
 759
 760     //wxThreadGuiExit();
 761
 762     delete gs_mutexGui;
 763
 764     // and free TLD slot
 765     (void)pthread_key_delete(gs_keySelf);
 766 }
 767
 768 // ----------------------------------------------------------------------------
 769 // global functions
 770 // ----------------------------------------------------------------------------
 771
 772 void wxMutexGuiEnter()
 773 {
 774   gs_mutexGui->Lock();
 775 }
 776
 777 void wxMutexGuiLeave()
 778 {
 779   gs_mutexGui->Unlock();
 780 }
 781