samples/thread/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        thread.cpp
   3 // Purpose:     wxWindows thread sample
   4 // Author:      Julian Smart(minimal)/Guilhem Lavaux(thread test)
   5 // Modified by:
   6 // Created:     06/16/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart, Markus Holzem, Guilhem Lavaux
   9 // Licence:     wxWindows license
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 /*
  13     TODO: use worker threads to update progress controls instead of writing
  14           messages - it will be more visual
  15  */
  16
  17 // For compilers that support precompilation, includes "wx/wx.h".
  18 #include "wx/wxprec.h"
  19
  20 #ifdef __BORLANDC__
  21     #pragma hdrstop
  22 #endif
  23
  24 #ifndef WX_PRECOMP
  25     #include "wx/wx.h"
  26 #endif
  27
  28 #if !wxUSE_THREADS
  29     #error "This sample requires thread support!"
  30 #endif // wxUSE_THREADS
  31
  32 #include "wx/thread.h"
  33 #include "wx/dynarray.h"
  34 #include "wx/time.h"
  35
  36 #include "wx/progdlg.h"
  37
  38 #define USE_EXECUTE
  39 #ifdef USE_EXECUTE
  40     #define EXEC(cmd) wxExecute((cmd), wxEXEC_SYNC)
  41 #else
  42     #define EXEC(cmd) system(cmd)
  43 #endif
  44
  45 class MyThread;
  46 WX_DEFINE_ARRAY(wxThread *, wxArrayThread);
  47
  48 // Define a new application type
  49 class MyApp : public wxApp
  50 {
  51 public:
  52     virtual bool OnInit();
  53
  54 public:
  55     // all the threads currently alive - as soon as the thread terminates, it's
  56     // removed from the array
  57     wxArrayThread m_threads;
  58
  59     // crit section protects access to all of the arrays below
  60     wxCriticalSection m_critsect;
  61 };
  62
  63 // Create a new application object
  64 IMPLEMENT_APP(MyApp)
  65
  66 // Define a new frame type
  67 class MyFrame: public wxFrame
  68 {
  69 public:
  70     // ctor
  71     MyFrame(wxFrame *frame, const wxString& title, int x, int y, int w, int h);
  72
  73     // operations
  74     void WriteText(const wxString& text) { m_txtctrl->WriteText(text); }
  75
  76     // accessors for MyWorkerThread (called in its context!)
  77     bool Cancelled();
  78
  79     // callbacks
  80     void OnQuit(wxCommandEvent& event);
  81     void OnClear(wxCommandEvent& event);
  82
  83     void OnStartThread(wxCommandEvent& event);
  84     void OnStartThreads(wxCommandEvent& event);
  85     void OnStopThread(wxCommandEvent& event);
  86     void OnPauseThread(wxCommandEvent& event);
  87     void OnResumeThread(wxCommandEvent& event);
  88
  89     void OnStartWorker(wxCommandEvent& event);
  90     void OnWorkerEvent(wxCommandEvent& event);
  91     void OnUpdateWorker(wxUpdateUIEvent& event);
  92
  93     void OnExecMain(wxCommandEvent& event);
  94     void OnExecThread(wxCommandEvent& event);
  95
  96     void OnShowCPUs(wxCommandEvent& event);
  97     void OnAbout(wxCommandEvent& event);
  98
  99     void OnIdle(wxIdleEvent &event);
 100
 101 private:
 102     // helper function - creates a new thread (but doesn't run it)
 103     MyThread *CreateThread();
 104
 105     // just some place to put our messages in
 106     wxTextCtrl *m_txtctrl;
 107
 108     // remember the number of running threads and total number of threads
 109     size_t m_nRunning, m_nCount;
 110
 111     // the progress dialog which we show while worker thread is running
 112     wxProgressDialog *m_dlgProgress;
 113
 114     // was the worker thread cancelled by user?
 115     bool m_cancelled;
 116
 117     // protects m_cancelled
 118     wxCriticalSection m_critsectWork;
 119
 120     DECLARE_EVENT_TABLE()
 121 };
 122
 123 // ID for the menu commands
 124 enum
 125 {
 126     THREAD_QUIT          = 1,
 127     THREAD_TEXT          = 101,
 128     THREAD_CLEAR,
 129     THREAD_START_THREAD  = 201,
 130     THREAD_START_THREADS,
 131     THREAD_STOP_THREAD,
 132     THREAD_PAUSE_THREAD,
 133     THREAD_RESUME_THREAD,
 134     THREAD_START_WORKER,
 135
 136     THREAD_EXEC_MAIN,
 137     THREAD_EXEC_THREAD,
 138
 139     THREAD_SHOWCPUS,
 140     THREAD_ABOUT,
 141
 142     WORKER_EVENT    // this one gets sent from the worker thread
 143 };
 144
 145 // ----------------------------------------------------------------------------
 146 // GUI thread
 147 // ----------------------------------------------------------------------------
 148
 149 class MyThread : public wxThread
 150 {
 151 public:
 152     MyThread(MyFrame *frame);
 153
 154     // thread execution starts here
 155     virtual void *Entry();
 156
 157     // called when the thread exits - whether it terminates normally or is
 158     // stopped with Delete() (but not when it is Kill()ed!)
 159     virtual void OnExit();
 160
 161     // write something to the text control
 162     void WriteText(const wxString& text);
 163
 164 public:
 165     size_t   m_count;
 166     MyFrame *m_frame;
 167 };
 168
 169 MyThread::MyThread(MyFrame *frame)
 170         : wxThread()
 171 {
 172     m_count = 0;
 173     m_frame = frame;
 174 }
 175
 176 void MyThread::WriteText(const wxString& text)
 177 {
 178     wxString msg;
 179
 180     // before doing any GUI calls we must ensure that this thread is the only
 181     // one doing it!
 182
 183     wxMutexGuiEnter();
 184
 185     msg << text;
 186     m_frame->WriteText(msg);
 187
 188     wxMutexGuiLeave();
 189 }
 190
 191 void MyThread::OnExit()
 192 {
 193     wxCriticalSectionLocker locker(wxGetApp().m_critsect);
 194
 195     wxGetApp().m_threads.Remove(this);
 196 }
 197
 198 void *MyThread::Entry()
 199 {
 200     wxString text;
 201
 202     text.Printf(wxT("Thread 0x%x started (priority = %d).\n"),
 203                 GetId(), GetPriority());
 204     WriteText(text);
 205     // wxLogMessage(text); -- test wxLog thread safeness
 206
 207     for ( m_count = 0; m_count < 10; m_count++ )
 208     {
 209         // check if we were asked to exit
 210         if ( TestDestroy() )
 211             break;
 212
 213         text.Printf(wxT("[%u] Thread 0x%x here.\n"), m_count, GetId());
 214         WriteText(text);
 215
 216         // wxSleep() can't be called from non-GUI thread!
 217         wxThread::Sleep(1000);
 218     }
 219
 220     text.Printf(wxT("Thread 0x%x finished.\n"), GetId());
 221     WriteText(text);
 222     // wxLogMessage(text); -- test wxLog thread safeness
 223
 224     return NULL;
 225 }
 226
 227 // ----------------------------------------------------------------------------
 228 // worker thread
 229 // ----------------------------------------------------------------------------
 230
 231 class MyWorkerThread : public wxThread
 232 {
 233 public:
 234     MyWorkerThread(MyFrame *frame);
 235
 236     // thread execution starts here
 237     virtual void *Entry();
 238
 239     // called when the thread exits - whether it terminates normally or is
 240     // stopped with Delete() (but not when it is Kill()ed!)
 241     virtual void OnExit();
 242
 243 public:
 244     MyFrame *m_frame;
 245     size_t   m_count;
 246 };
 247
 248 MyWorkerThread::MyWorkerThread(MyFrame *frame)
 249         : wxThread()
 250 {
 251     m_frame = frame;
 252     m_count = 0;
 253 }
 254
 255 void MyWorkerThread::OnExit()
 256 {
 257 }
 258
 259 void *MyWorkerThread::Entry()
 260 {
 261     for ( m_count = 0; !m_frame->Cancelled() && (m_count < 100); m_count++ )
 262     {
 263         // check if we were asked to exit
 264         if ( TestDestroy() )
 265             break;
 266
 267         // create any type of command event here
 268         wxCommandEvent event( wxEVT_COMMAND_MENU_SELECTED, WORKER_EVENT );
 269         event.SetInt( m_count );
 270
 271         // send in a thread-safe way
 272         wxPostEvent( m_frame, event );
 273
 274         // wxSleep() can't be called from non-main thread!
 275         wxThread::Sleep(200);
 276     }
 277
 278     wxCommandEvent event( wxEVT_COMMAND_MENU_SELECTED, WORKER_EVENT );
 279     event.SetInt(-1); // that's all
 280     wxPostEvent( m_frame, event );
 281
 282     return NULL;
 283 }
 284
 285 // ----------------------------------------------------------------------------
 286 // a thread which simply calls wxExecute
 287 // ----------------------------------------------------------------------------
 288
 289 class MyExecThread : public wxThread
 290 {
 291 public:
 292     MyExecThread(const wxChar *command) : wxThread(wxTHREAD_JOINABLE),
 293                                           m_command(command)
 294     {
 295         Create();
 296     }
 297
 298     virtual ExitCode Entry()
 299     {
 300         return (ExitCode)EXEC(m_command);
 301     }
 302
 303 private:
 304     wxString m_command;
 305 };
 306
 307 // ----------------------------------------------------------------------------
 308 // implementation
 309 // ----------------------------------------------------------------------------
 310
 311 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 312     EVT_MENU(THREAD_QUIT, MyFrame::OnQuit)
 313     EVT_MENU(THREAD_CLEAR, MyFrame::OnClear)
 314     EVT_MENU(THREAD_START_THREAD, MyFrame::OnStartThread)
 315     EVT_MENU(THREAD_START_THREADS, MyFrame::OnStartThreads)
 316     EVT_MENU(THREAD_STOP_THREAD, MyFrame::OnStopThread)
 317     EVT_MENU(THREAD_PAUSE_THREAD, MyFrame::OnPauseThread)
 318     EVT_MENU(THREAD_RESUME_THREAD, MyFrame::OnResumeThread)
 319
 320     EVT_MENU(THREAD_EXEC_MAIN, MyFrame::OnExecMain)
 321     EVT_MENU(THREAD_EXEC_THREAD, MyFrame::OnExecThread)
 322
 323     EVT_MENU(THREAD_SHOWCPUS, MyFrame::OnShowCPUs)
 324     EVT_MENU(THREAD_ABOUT, MyFrame::OnAbout)
 325
 326     EVT_UPDATE_UI(THREAD_START_WORKER, MyFrame::OnUpdateWorker)
 327     EVT_MENU(THREAD_START_WORKER, MyFrame::OnStartWorker)
 328     EVT_MENU(WORKER_EVENT, MyFrame::OnWorkerEvent)
 329
 330     EVT_IDLE(MyFrame::OnIdle)
 331 END_EVENT_TABLE()
 332
 333 // `Main program' equivalent, creating windows and returning main app frame
 334 bool MyApp::OnInit()
 335 {
 336     // uncomment this to get some debugging messages from the trace code
 337     // on the console (or just set WXTRACE env variable to include "thread")
 338     //wxLog::AddTraceMask("thread");
 339
 340     // Create the main frame window
 341     MyFrame *frame = new MyFrame((wxFrame *)NULL, "wxWindows threads sample",
 342                                  50, 50, 450, 340);
 343
 344     // Make a menubar
 345     wxMenuBar *menuBar = new wxMenuBar;
 346
 347     wxMenu *menuFile = new wxMenu;
 348     menuFile->Append(THREAD_CLEAR, "&Clear log\tCtrl-L");
 349     menuFile->AppendSeparator();
 350     menuFile->Append(THREAD_QUIT, "E&xit\tAlt-X");
 351     menuBar->Append(menuFile, "&File");
 352
 353     wxMenu *menuThread = new wxMenu;
 354     menuThread->Append(THREAD_START_THREAD, "&Start a new thread\tCtrl-N");
 355     menuThread->Append(THREAD_START_THREADS, "Start &many threads at once");
 356     menuThread->Append(THREAD_STOP_THREAD, "S&top a running thread\tCtrl-S");
 357     menuThread->AppendSeparator();
 358     menuThread->Append(THREAD_PAUSE_THREAD, "&Pause a running thread\tCtrl-P");
 359     menuThread->Append(THREAD_RESUME_THREAD, "&Resume suspended thread\tCtrl-R");
 360     menuThread->AppendSeparator();
 361     menuThread->Append(THREAD_START_WORKER, "Start &worker thread\tCtrl-W");
 362     menuBar->Append(menuThread, "&Thread");
 363
 364     wxMenu *menuExec = new wxMenu;
 365     menuExec->Append(THREAD_EXEC_MAIN, "&Launch a program from main thread\tF5");
 366     menuExec->Append(THREAD_EXEC_THREAD, "L&aunch a program from a thread\tCtrl-F5");
 367     menuBar->Append(menuExec, "&Execute");
 368
 369     wxMenu *menuHelp = new wxMenu;
 370     menuHelp->Append(THREAD_SHOWCPUS, "&Show CPU count");
 371     menuHelp->AppendSeparator();
 372     menuHelp->Append(THREAD_ABOUT, "&About...");
 373     menuBar->Append(menuHelp, "&Help");
 374
 375     frame->SetMenuBar(menuBar);
 376
 377     // Show the frame
 378     frame->Show(TRUE);
 379
 380     SetTopWindow(frame);
 381
 382     return TRUE;
 383 }
 384
 385 // My frame constructor
 386 MyFrame::MyFrame(wxFrame *frame, const wxString& title,
 387                  int x, int y, int w, int h)
 388        : wxFrame(frame, -1, title, wxPoint(x, y), wxSize(w, h))
 389 {
 390     m_nRunning = m_nCount = 0;
 391
 392     m_dlgProgress = (wxProgressDialog *)NULL;
 393
 394     CreateStatusBar(2);
 395
 396     m_txtctrl = new wxTextCtrl(this, -1, "", wxPoint(0, 0), wxSize(0, 0),
 397                                wxTE_MULTILINE | wxTE_READONLY);
 398
 399 }
 400
 401 MyThread *MyFrame::CreateThread()
 402 {
 403     MyThread *thread = new MyThread(this);
 404
 405     if ( thread->Create() != wxTHREAD_NO_ERROR )
 406     {
 407         wxLogError(wxT("Can't create thread!"));
 408     }
 409
 410     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 411     wxGetApp().m_threads.Add(thread);
 412
 413     return thread;
 414 }
 415
 416 void MyFrame::OnStartThreads(wxCommandEvent& WXUNUSED(event) )
 417 {
 418     static long s_num = 10;
 419
 420     s_num = wxGetNumberFromUser("How many threads to start: ", "",
 421                                 "wxThread sample", s_num, 1, 10000, this);
 422     if ( s_num == -1 )
 423     {
 424         s_num = 10;
 425
 426         return;
 427     }
 428
 429     size_t count = (size_t)s_num, n;
 430
 431     wxArrayThread threads;
 432
 433     // first create them all...
 434     for ( n = 0; n < count; n++ )
 435     {
 436         wxThread *thr = CreateThread();
 437
 438         // we want to show the effect of SetPriority(): the first thread will
 439         // have the lowest priority, the second - the highest, all the rest
 440         // the normal one
 441         if ( n == 0 )
 442             thr->SetPriority(WXTHREAD_MIN_PRIORITY);
 443         else if ( n == 1 )
 444             thr->SetPriority(WXTHREAD_MAX_PRIORITY);
 445         else
 446             thr->SetPriority(WXTHREAD_DEFAULT_PRIORITY);
 447
 448         threads.Add(thr);
 449     }
 450
 451     wxString msg;
 452     msg.Printf(wxT("%d new threads created."), count);
 453     SetStatusText(msg, 1);
 454
 455     // ...and then start them
 456     for ( n = 0; n < count; n++ )
 457     {
 458         threads[n]->Run();
 459     }
 460 }
 461
 462 void MyFrame::OnStartThread(wxCommandEvent& WXUNUSED(event) )
 463 {
 464     MyThread *thread = CreateThread();
 465
 466     if ( thread->Run() != wxTHREAD_NO_ERROR )
 467     {
 468         wxLogError(wxT("Can't start thread!"));
 469     }
 470
 471     SetStatusText("New thread started.", 1);
 472 }
 473
 474 void MyFrame::OnStopThread(wxCommandEvent& WXUNUSED(event) )
 475 {
 476     wxGetApp().m_critsect.Enter();
 477
 478     // stop the last thread
 479     if ( wxGetApp().m_threads.IsEmpty() )
 480     {
 481         wxLogError(wxT("No thread to stop!"));
 482
 483         wxGetApp().m_critsect.Leave();
 484     }
 485     else
 486     {
 487         wxThread *thread = wxGetApp().m_threads.Last();
 488
 489         // it's important to leave critical section before calling Delete()
 490         // because delete will (implicitly) call OnExit() which also tries
 491         // to enter the same crit section - would dead lock.
 492         wxGetApp().m_critsect.Leave();
 493
 494         thread->Delete();
 495
 496         SetStatusText("Thread stopped.", 1);
 497     }
 498 }
 499
 500 void MyFrame::OnResumeThread(wxCommandEvent& WXUNUSED(event) )
 501 {
 502     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 503
 504     // resume first suspended thread
 505     size_t n = 0, count = wxGetApp().m_threads.Count();
 506     while ( n < count && !wxGetApp().m_threads[n]->IsPaused() )
 507         n++;
 508
 509     if ( n == count )
 510     {
 511         wxLogError(wxT("No thread to resume!"));
 512     }
 513     else
 514     {
 515         wxGetApp().m_threads[n]->Resume();
 516
 517         SetStatusText("Thread resumed.", 1);
 518     }
 519 }
 520
 521 void MyFrame::OnPauseThread(wxCommandEvent& WXUNUSED(event) )
 522 {
 523     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 524
 525     // pause last running thread
 526     int n = wxGetApp().m_threads.Count() - 1;
 527     while ( n >= 0 && !wxGetApp().m_threads[n]->IsRunning() )
 528         n--;
 529
 530     if ( n < 0 )
 531     {
 532         wxLogError(wxT("No thread to pause!"));
 533     }
 534     else
 535     {
 536         wxGetApp().m_threads[n]->Pause();
 537
 538         SetStatusText("Thread paused.", 1);
 539     }
 540 }
 541
 542 // set the frame title indicating the current number of threads
 543 void MyFrame::OnIdle(wxIdleEvent &event)
 544 {
 545     // update the counts of running/total threads
 546     size_t nRunning = 0,
 547            nCount = wxGetApp().m_threads.Count();
 548     for ( size_t n = 0; n < nCount; n++ )
 549     {
 550         if ( wxGetApp().m_threads[n]->IsRunning() )
 551             nRunning++;
 552     }
 553
 554     if ( nCount != m_nCount || nRunning != m_nRunning )
 555     {
 556         m_nRunning = nRunning;
 557         m_nCount = nCount;
 558
 559         wxLogStatus(this, wxT("%u threads total, %u running."), nCount, nRunning);
 560     }
 561     //else: avoid flicker - don't print anything
 562 }
 563
 564 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event) )
 565 {
 566     size_t count = wxGetApp().m_threads.Count();
 567     for ( size_t i = 0; i < count; i++ )
 568     {
 569         wxGetApp().m_threads[0]->Delete();
 570     }
 571
 572     Close(TRUE);
 573 }
 574
 575 void MyFrame::OnExecMain(wxCommandEvent& WXUNUSED(event))
 576 {
 577     wxLogMessage("The exit code from the main program is %ld",
 578                  EXEC("/bin/echo \"main program\""));
 579 }
 580
 581 void MyFrame::OnExecThread(wxCommandEvent& WXUNUSED(event))
 582 {
 583     MyExecThread thread("/bin/echo \"child thread\"");
 584     thread.Run();
 585
 586     wxLogMessage("The exit code from a child thread is %ld",
 587                  (long)thread.Wait());
 588 }
 589
 590 void MyFrame::OnShowCPUs(wxCommandEvent& WXUNUSED(event))
 591 {
 592     wxString msg;
 593
 594     int nCPUs = wxThread::GetCPUCount();
 595     switch ( nCPUs )
 596     {
 597         case -1:
 598             msg = "Unknown number of CPUs";
 599             break;
 600
 601         case 0:
 602             msg = "WARNING: you're running without any CPUs!";
 603             break;
 604
 605         case 1:
 606             msg = "This system only has one CPU.";
 607             break;
 608
 609         default:
 610             msg.Printf("This system has %d CPUs", nCPUs);
 611     }
 612
 613     wxLogMessage(msg);
 614 }
 615
 616 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event) )
 617 {
 618     wxMessageDialog dialog(this, "wxWindows multithreaded application sample\n"
 619                                  "(c) 1998 Julian Smart, Guilhem Lavaux\n"
 620                                  "(c) 1999 Vadim Zeitlin\n"
 621                                  "(c) 2000 Robert Roebling",
 622                            "About wxThread sample",
 623                            wxOK | wxICON_INFORMATION);
 624
 625     dialog.ShowModal();
 626 }
 627
 628 void MyFrame::OnClear(wxCommandEvent& WXUNUSED(event))
 629 {
 630     m_txtctrl->Clear();
 631 }
 632
 633 void MyFrame::OnUpdateWorker(wxUpdateUIEvent& event)
 634 {
 635     event.Enable( m_dlgProgress == NULL );
 636 }
 637
 638 void MyFrame::OnStartWorker(wxCommandEvent& WXUNUSED(event))
 639 {
 640     MyWorkerThread *thread = new MyWorkerThread(this);
 641
 642     if ( thread->Create() != wxTHREAD_NO_ERROR )
 643     {
 644         wxLogError(wxT("Can't create thread!"));
 645     }
 646
 647     m_dlgProgress = new wxProgressDialog
 648                         (
 649                          "Progress dialog",
 650                          "Wait until the thread terminates or press [Cancel]",
 651                          100,
 652                          this,
 653                          wxPD_CAN_ABORT |
 654                          wxPD_APP_MODAL |
 655                          wxPD_ELAPSED_TIME |
 656                          wxPD_ESTIMATED_TIME |
 657                          wxPD_REMAINING_TIME
 658                         );
 659
 660     // thread is not running yet, no need for crit sect
 661     m_cancelled = FALSE;
 662
 663     thread->Run();
 664 }
 665
 666 void MyFrame::OnWorkerEvent(wxCommandEvent& event)
 667 {
 668 #if 0
 669     WriteText( "Got message from worker thread: " );
 670     WriteText( event.GetString() );
 671     WriteText( "\n" );
 672 #else
 673     int n = event.GetInt();
 674     if ( n == -1 )
 675     {
 676         m_dlgProgress->Destroy();
 677         m_dlgProgress = (wxProgressDialog *)NULL;
 678
 679         // the dialog is aborted because the event came from another thread, so
 680         // we may need to wake up the main event loop for the dialog to be
 681         // really closed
 682         wxWakeUpIdle();
 683     }
 684     else
 685     {
 686         if ( !m_dlgProgress->Update(n) )
 687         {
 688             wxCriticalSectionLocker lock(m_critsectWork);
 689
 690             m_cancelled = TRUE;
 691         }
 692     }
 693 #endif
 694 }
 695
 696 bool MyFrame::Cancelled()
 697 {
 698     wxCriticalSectionLocker lock(m_critsectWork);
 699
 700     return m_cancelled;
 701 }