samples/thread/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        thread.cpp
   3 // Purpose:     wxWidgets thread sample
   4 // Author:      Guilhem Lavaux, Vadim Zeitlin
   5 // Modified by:
   6 // Created:     06/16/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 1998-2009 wxWidgets team
   9 // Licence:     wxWindows license
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx/wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #ifndef WX_PRECOMP
  28     #include "wx/wx.h"
  29 #endif
  30
  31 #if !wxUSE_THREADS
  32     #error "This sample requires thread support!"
  33 #endif // wxUSE_THREADS
  34
  35 #include "wx/thread.h"
  36 #include "wx/dynarray.h"
  37 #include "wx/numdlg.h"
  38 #include "wx/progdlg.h"
  39
  40 // ----------------------------------------------------------------------------
  41 // resources
  42 // ----------------------------------------------------------------------------
  43
  44 #include "../sample.xpm"
  45
  46 // ----------------------------------------------------------------------------
  47 // private classes
  48 // ----------------------------------------------------------------------------
  49
  50 // define this to use wxExecute in the exec tests, otherwise just use system
  51 #define USE_EXECUTE
  52
  53 #ifdef USE_EXECUTE
  54     #define EXEC(cmd) wxExecute((cmd), wxEXEC_SYNC)
  55 #else
  56     #define EXEC(cmd) system(cmd)
  57 #endif
  58
  59 class MyThread;
  60 WX_DEFINE_ARRAY_PTR(wxThread *, wxArrayThread);
  61
  62 // ----------------------------------------------------------------------------
  63 // the application object
  64 // ----------------------------------------------------------------------------
  65
  66 class MyApp : public wxApp
  67 {
  68 public:
  69     MyApp();
  70     virtual ~MyApp(){};
  71
  72     virtual bool OnInit();
  73
  74     // critical section protects access to all of the fields below
  75     wxCriticalSection m_critsect;
  76
  77     // all the threads currently alive - as soon as the thread terminates, it's
  78     // removed from the array
  79     wxArrayThread m_threads;
  80
  81     // semaphore used to wait for the threads to exit, see MyFrame::OnQuit()
  82     wxSemaphore m_semAllDone;
  83
  84     // indicates that we're shutting down and all threads should exit
  85     bool m_shuttingDown;
  86 };
  87
  88 // ----------------------------------------------------------------------------
  89 // the main application frame
  90 // ----------------------------------------------------------------------------
  91
  92 class MyFrame : public wxFrame,
  93                 private wxLog
  94 {
  95 public:
  96     // ctor
  97     MyFrame(const wxString& title);
  98     virtual ~MyFrame();
  99
 100     // accessors for MyWorkerThread (called in its context!)
 101     bool Cancelled();
 102
 103 protected:
 104     virtual void DoLogRecord(wxLogLevel level,
 105                              const wxString& msg,
 106                              const wxLogRecordInfo& info);
 107
 108 private:
 109     // event handlers
 110     // --------------
 111
 112     void OnQuit(wxCommandEvent& event);
 113     void OnClear(wxCommandEvent& event);
 114
 115     void OnStartThread(wxCommandEvent& event);
 116     void OnStartThreads(wxCommandEvent& event);
 117     void OnStopThread(wxCommandEvent& event);
 118     void OnPauseThread(wxCommandEvent& event);
 119     void OnResumeThread(wxCommandEvent& event);
 120
 121     void OnStartWorker(wxCommandEvent& event);
 122     void OnExecMain(wxCommandEvent& event);
 123     void OnStartGUIThread(wxCommandEvent& event);
 124
 125     void OnShowCPUs(wxCommandEvent& event);
 126     void OnAbout(wxCommandEvent& event);
 127
 128     void OnIdle(wxIdleEvent &event);
 129     void OnWorkerEvent(wxThreadEvent& event);
 130     void OnUpdateWorker(wxUpdateUIEvent& event);
 131
 132
 133     // logging helper
 134     void DoLogLine(wxTextCtrl *text,
 135                    const wxString& timestr,
 136                    const wxString& threadstr,
 137                    const wxString& msg);
 138
 139
 140     // thread helper functions
 141     // -----------------------
 142
 143     // helper function - creates a new thread (but doesn't run it)
 144     MyThread *CreateThread();
 145
 146     // update display in our status bar: called during idle handling
 147     void UpdateThreadStatus();
 148
 149
 150     // internal variables
 151     // ------------------
 152
 153     // just some place to put our messages in
 154     wxTextCtrl *m_txtctrl;
 155
 156     // old log target, we replace it with one using m_txtctrl during this
 157     // frame life time
 158     wxLog *m_oldLogger;
 159
 160     // the array of pending messages to be displayed and the critical section
 161     // protecting it
 162     wxArrayString m_messages;
 163     wxCriticalSection m_csMessages;
 164
 165     // remember the number of running threads and total number of threads
 166     size_t m_nRunning,
 167            m_nCount;
 168
 169     // the progress dialog which we show while worker thread is running
 170     wxProgressDialog *m_dlgProgress;
 171
 172     // was the worker thread cancelled by user?
 173     bool m_cancelled;
 174     wxCriticalSection m_csCancelled;        // protects m_cancelled
 175
 176     DECLARE_EVENT_TABLE()
 177 };
 178
 179 // ----------------------------------------------------------------------------
 180 // constants
 181 // ----------------------------------------------------------------------------
 182
 183 // ID for the menu commands
 184 enum
 185 {
 186     THREAD_QUIT  = wxID_EXIT,
 187     THREAD_ABOUT = wxID_ABOUT,
 188     THREAD_TEXT          = 101,
 189     THREAD_CLEAR,
 190     THREAD_START_THREAD  = 201,
 191     THREAD_START_THREADS,
 192     THREAD_STOP_THREAD,
 193     THREAD_PAUSE_THREAD,
 194     THREAD_RESUME_THREAD,
 195
 196     THREAD_START_WORKER,
 197     THREAD_EXEC_MAIN,
 198     THREAD_START_GUI_THREAD,
 199
 200     THREAD_SHOWCPUS,
 201
 202     WORKER_EVENT = wxID_HIGHEST+1,   // this one gets sent from MyWorkerThread
 203     GUITHREAD_EVENT                  // this one gets sent from MyGUIThread
 204 };
 205
 206 // ----------------------------------------------------------------------------
 207 // a simple thread
 208 // ----------------------------------------------------------------------------
 209
 210 class MyThread : public wxThread
 211 {
 212 public:
 213     MyThread();
 214     virtual ~MyThread();
 215
 216     // thread execution starts here
 217     virtual void *Entry();
 218
 219 public:
 220     unsigned m_count;
 221 };
 222
 223 // ----------------------------------------------------------------------------
 224 // a worker thread
 225 // ----------------------------------------------------------------------------
 226
 227 class MyWorkerThread : public wxThread
 228 {
 229 public:
 230     MyWorkerThread(MyFrame *frame);
 231
 232     // thread execution starts here
 233     virtual void *Entry();
 234
 235     // called when the thread exits - whether it terminates normally or is
 236     // stopped with Delete() (but not when it is Kill()ed!)
 237     virtual void OnExit();
 238
 239 public:
 240     MyFrame *m_frame;
 241     unsigned m_count;
 242 };
 243
 244 // ----------------------------------------------------------------------------
 245 // a thread which executes GUI calls using wxMutexGuiEnter/Leave
 246 // ----------------------------------------------------------------------------
 247
 248 #define GUITHREAD_BMP_SIZE          300
 249 #define GUITHREAD_NUM_UPDATES       50
 250 class MyImageDialog;
 251
 252 class MyGUIThread : public wxThread
 253 {
 254 public:
 255     MyGUIThread(MyImageDialog *dlg) : wxThread(wxTHREAD_JOINABLE)
 256     {
 257         m_dlg = dlg;
 258     }
 259
 260     virtual ExitCode Entry();
 261
 262 private:
 263     MyImageDialog *m_dlg;
 264 };
 265
 266 // ----------------------------------------------------------------------------
 267 // an helper dialog used by MyFrame::OnStartGUIThread
 268 // ----------------------------------------------------------------------------
 269
 270 class MyImageDialog: public wxDialog
 271 {
 272 public:
 273     // ctor
 274     MyImageDialog(wxFrame *frame);
 275     ~MyImageDialog();
 276
 277     // stuff used by MyGUIThread:
 278     wxBitmap m_bmp;    // the bitmap drawn by MyGUIThread
 279     wxCriticalSection m_csBmp;        // protects m_bmp
 280
 281 private:
 282     void OnGUIThreadEvent(wxThreadEvent& event);
 283     void OnPaint(wxPaintEvent&);
 284
 285     MyGUIThread m_thread;
 286     int m_nCurrentProgress;
 287
 288     DECLARE_EVENT_TABLE()
 289 };
 290
 291 // ============================================================================
 292 // implementation
 293 // ============================================================================
 294
 295 // ----------------------------------------------------------------------------
 296 // the application class
 297 // ----------------------------------------------------------------------------
 298
 299 // Create a new application object
 300 IMPLEMENT_APP(MyApp)
 301
 302 MyApp::MyApp()
 303 {
 304     m_shuttingDown = false;
 305 }
 306
 307 // `Main program' equivalent, creating windows and returning main app frame
 308 bool MyApp::OnInit()
 309 {
 310     if ( !wxApp::OnInit() )
 311         return false;
 312
 313     // uncomment this to get some debugging messages from the trace code
 314     // on the console (or just set WXTRACE env variable to include "thread")
 315     wxLog::AddTraceMask("thread");
 316
 317     // Create the main frame window
 318     new MyFrame("wxWidgets threads sample");
 319
 320     return true;
 321 }
 322
 323 // ----------------------------------------------------------------------------
 324 // MyFrame
 325 // ----------------------------------------------------------------------------
 326
 327 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 328     EVT_MENU(THREAD_QUIT, MyFrame::OnQuit)
 329     EVT_MENU(THREAD_CLEAR, MyFrame::OnClear)
 330     EVT_MENU(THREAD_START_THREAD, MyFrame::OnStartThread)
 331     EVT_MENU(THREAD_START_THREADS, MyFrame::OnStartThreads)
 332     EVT_MENU(THREAD_STOP_THREAD, MyFrame::OnStopThread)
 333     EVT_MENU(THREAD_PAUSE_THREAD, MyFrame::OnPauseThread)
 334     EVT_MENU(THREAD_RESUME_THREAD, MyFrame::OnResumeThread)
 335
 336     EVT_MENU(THREAD_START_WORKER, MyFrame::OnStartWorker)
 337     EVT_MENU(THREAD_EXEC_MAIN, MyFrame::OnExecMain)
 338     EVT_MENU(THREAD_START_GUI_THREAD, MyFrame::OnStartGUIThread)
 339
 340     EVT_MENU(THREAD_SHOWCPUS, MyFrame::OnShowCPUs)
 341     EVT_MENU(THREAD_ABOUT, MyFrame::OnAbout)
 342
 343     EVT_UPDATE_UI(THREAD_START_WORKER, MyFrame::OnUpdateWorker)
 344     EVT_THREAD(WORKER_EVENT, MyFrame::OnWorkerEvent)
 345     EVT_IDLE(MyFrame::OnIdle)
 346 END_EVENT_TABLE()
 347
 348 // My frame constructor
 349 MyFrame::MyFrame(const wxString& title)
 350        : wxFrame(NULL, wxID_ANY, title)
 351 {
 352     m_oldLogger = wxLog::GetActiveTarget();
 353
 354     SetIcon(wxIcon(sample_xpm));
 355
 356     // Make a menubar
 357     wxMenuBar *menuBar = new wxMenuBar;
 358
 359     wxMenu *menuFile = new wxMenu;
 360     menuFile->Append(THREAD_CLEAR, wxT("&Clear log\tCtrl-L"));
 361     menuFile->AppendSeparator();
 362     menuFile->Append(THREAD_QUIT, wxT("E&xit\tAlt-X"));
 363     menuBar->Append(menuFile, wxT("&File"));
 364
 365     wxMenu *menuThread = new wxMenu;
 366     menuThread->Append(THREAD_START_THREAD, wxT("&Start a new thread\tCtrl-N"));
 367     menuThread->Append(THREAD_START_THREADS, wxT("Start &many threads at once"));
 368     menuThread->Append(THREAD_STOP_THREAD, wxT("S&top the last spawned thread\tCtrl-S"));
 369     menuThread->AppendSeparator();
 370     menuThread->Append(THREAD_PAUSE_THREAD, wxT("&Pause the last spawned running thread\tCtrl-P"));
 371     menuThread->Append(THREAD_RESUME_THREAD, wxT("&Resume the first suspended thread\tCtrl-R"));
 372     menuThread->AppendSeparator();
 373     menuThread->Append(THREAD_START_WORKER, wxT("Start a &worker thread\tCtrl-W"));
 374     menuThread->Append(THREAD_EXEC_MAIN, wxT("&Launch a program from main thread\tF5"));
 375     menuThread->Append(THREAD_START_GUI_THREAD, wxT("Launch a &GUI thread\tF6"));
 376     menuBar->Append(menuThread, wxT("&Thread"));
 377
 378     wxMenu *menuHelp = new wxMenu;
 379     menuHelp->Append(THREAD_SHOWCPUS, wxT("&Show CPU count"));
 380     menuHelp->AppendSeparator();
 381     menuHelp->Append(THREAD_ABOUT, wxT("&About..."));
 382     menuBar->Append(menuHelp, wxT("&Help"));
 383
 384     SetMenuBar(menuBar);
 385
 386     m_nRunning = m_nCount = 0;
 387
 388     m_dlgProgress = NULL;
 389
 390 #if wxUSE_STATUSBAR
 391     CreateStatusBar(2);
 392 #endif // wxUSE_STATUSBAR
 393
 394     // create the logging text control and a header showing the meaning of the
 395     // different columns
 396     wxTextCtrl *header = new wxTextCtrl(this, wxID_ANY, "",
 397                                         wxDefaultPosition, wxDefaultSize,
 398                                         wxTE_READONLY);
 399     DoLogLine(header, "  Time", " Thread", "Message");
 400     m_txtctrl = new wxTextCtrl(this, wxID_ANY, "",
 401                                wxDefaultPosition, wxDefaultSize,
 402                                wxTE_MULTILINE | wxTE_READONLY);
 403     wxLog::SetActiveTarget(this);
 404
 405     // use fixed width font to align output in nice columns
 406     wxFont font(wxNORMAL_FONT->GetPointSize(), wxFONTFAMILY_TELETYPE,
 407                 wxFONTSTYLE_NORMAL, wxFONTWEIGHT_NORMAL);
 408     header->SetFont(font);
 409     m_txtctrl->SetFont(font);
 410
 411     m_txtctrl->SetFocus();
 412
 413     // layout and show the frame
 414     wxBoxSizer *sizer = new wxBoxSizer(wxVERTICAL);
 415     sizer->Add(header, wxSizerFlags().Expand());
 416     sizer->Add(m_txtctrl, wxSizerFlags(1).Expand());
 417     SetSizer(sizer);
 418
 419     SetSize(600, 350);
 420     Show();
 421 }
 422
 423 MyFrame::~MyFrame()
 424 {
 425     wxLog::SetActiveTarget(m_oldLogger);
 426
 427     // NB: although the OS will terminate all the threads anyhow when the main
 428     //     one exits, it's good practice to do it ourselves -- even if it's not
 429     //     completely trivial in this example
 430
 431     // tell all the threads to terminate: note that they can't terminate while
 432     // we're deleting them because they will block in their OnExit() -- this is
 433     // important as otherwise we might access invalid array elements
 434
 435     {
 436         wxCriticalSectionLocker locker(wxGetApp().m_critsect);
 437
 438         // check if we have any threads running first
 439         const wxArrayThread& threads = wxGetApp().m_threads;
 440         size_t count = threads.GetCount();
 441
 442         if ( !count )
 443             return;
 444
 445         // set the flag indicating that all threads should exit
 446         wxGetApp().m_shuttingDown = true;
 447     }
 448
 449     // now wait for them to really terminate
 450     wxGetApp().m_semAllDone.Wait();
 451 }
 452
 453 void
 454 MyFrame::DoLogLine(wxTextCtrl *text,
 455                    const wxString& timestr,
 456                    const wxString& threadstr,
 457                    const wxString& msg)
 458 {
 459     text->AppendText(wxString::Format("%9s %10s %s", timestr, threadstr, msg));
 460 }
 461
 462 void
 463 MyFrame::DoLogRecord(wxLogLevel level,
 464                      const wxString& msg,
 465                      const wxLogRecordInfo& info)
 466 {
 467     // let the default GUI logger treat warnings and errors as they should be
 468     // more noticeable than just another line in the log window and also trace
 469     // messages as there may be too many of them
 470     if ( level <= wxLOG_Warning || level == wxLOG_Trace )
 471     {
 472         m_oldLogger->LogRecord(level, msg, info);
 473         return;
 474     }
 475
 476     DoLogLine
 477     (
 478         m_txtctrl,
 479         wxDateTime(info.timestamp).FormatISOTime(),
 480         info.threadId == wxThread::GetMainId()
 481             ? wxString("main")
 482             : wxString::Format("%x", info.threadId),
 483         msg + "\n"
 484     );
 485 }
 486
 487 MyThread *MyFrame::CreateThread()
 488 {
 489     MyThread *thread = new MyThread;
 490
 491     if ( thread->Create() != wxTHREAD_NO_ERROR )
 492     {
 493         wxLogError(wxT("Can't create thread!"));
 494     }
 495
 496     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 497     wxGetApp().m_threads.Add(thread);
 498
 499     return thread;
 500 }
 501
 502 void MyFrame::UpdateThreadStatus()
 503 {
 504     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 505
 506     // update the counts of running/total threads
 507     size_t nRunning = 0,
 508            nCount = wxGetApp().m_threads.Count();
 509     for ( size_t n = 0; n < nCount; n++ )
 510     {
 511         if ( wxGetApp().m_threads[n]->IsRunning() )
 512             nRunning++;
 513     }
 514
 515     if ( nCount != m_nCount || nRunning != m_nRunning )
 516     {
 517         m_nRunning = nRunning;
 518         m_nCount = nCount;
 519
 520         wxLogStatus(this, wxT("%u threads total, %u running."), unsigned(nCount), unsigned(nRunning));
 521     }
 522     //else: avoid flicker - don't print anything
 523 }
 524
 525 bool MyFrame::Cancelled()
 526 {
 527     wxCriticalSectionLocker lock(m_csCancelled);
 528
 529     return m_cancelled;
 530 }
 531
 532 // ----------------------------------------------------------------------------
 533 // MyFrame - event handlers
 534 // ----------------------------------------------------------------------------
 535
 536 void MyFrame::OnStartThreads(wxCommandEvent& WXUNUSED(event) )
 537 {
 538     static long s_num;
 539
 540     s_num = wxGetNumberFromUser(wxT("How many threads to start: "), wxT(""),
 541                                 wxT("wxThread sample"), s_num, 1, 10000, this);
 542     if ( s_num == -1 )
 543     {
 544         s_num = 10;
 545
 546         return;
 547     }
 548
 549     unsigned count = unsigned(s_num), n;
 550
 551     wxArrayThread threads;
 552
 553     // first create them all...
 554     for ( n = 0; n < count; n++ )
 555     {
 556         wxThread *thr = CreateThread();
 557
 558         // we want to show the effect of SetPriority(): the first thread will
 559         // have the lowest priority, the second - the highest, all the rest
 560         // the normal one
 561         if ( n == 0 )
 562             thr->SetPriority(WXTHREAD_MIN_PRIORITY);
 563         else if ( n == 1 )
 564             thr->SetPriority(WXTHREAD_MAX_PRIORITY);
 565         else
 566             thr->SetPriority(WXTHREAD_DEFAULT_PRIORITY);
 567
 568         threads.Add(thr);
 569     }
 570
 571 #if wxUSE_STATUSBAR
 572     wxString msg;
 573     msg.Printf(wxT("%d new threads created."), count);
 574     SetStatusText(msg, 1);
 575 #endif // wxUSE_STATUSBAR
 576
 577     // ...and then start them
 578     for ( n = 0; n < count; n++ )
 579     {
 580         threads[n]->Run();
 581     }
 582 }
 583
 584 void MyFrame::OnStartThread(wxCommandEvent& WXUNUSED(event) )
 585 {
 586     MyThread *thread = CreateThread();
 587
 588     if ( thread->Run() != wxTHREAD_NO_ERROR )
 589     {
 590         wxLogError(wxT("Can't start thread!"));
 591     }
 592
 593 #if wxUSE_STATUSBAR
 594     SetStatusText(wxT("New thread started."), 1);
 595 #endif // wxUSE_STATUSBAR
 596 }
 597
 598 void MyFrame::OnStopThread(wxCommandEvent& WXUNUSED(event) )
 599 {
 600     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 601
 602     // stop the last thread
 603     if ( wxGetApp().m_threads.IsEmpty() )
 604     {
 605         wxLogError(wxT("No thread to stop!"));
 606     }
 607     else
 608     {
 609         wxGetApp().m_threads.Last()->Delete();
 610
 611 #if wxUSE_STATUSBAR
 612         SetStatusText(wxT("Last thread stopped."), 1);
 613 #endif // wxUSE_STATUSBAR
 614     }
 615 }
 616
 617 void MyFrame::OnResumeThread(wxCommandEvent& WXUNUSED(event) )
 618 {
 619     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 620
 621     // resume first suspended thread
 622     size_t n = 0, count = wxGetApp().m_threads.Count();
 623     while ( n < count && !wxGetApp().m_threads[n]->IsPaused() )
 624         n++;
 625
 626     if ( n == count )
 627     {
 628         wxLogError(wxT("No thread to resume!"));
 629     }
 630     else
 631     {
 632         wxGetApp().m_threads[n]->Resume();
 633
 634 #if wxUSE_STATUSBAR
 635         SetStatusText(wxT("Thread resumed."), 1);
 636 #endif // wxUSE_STATUSBAR
 637     }
 638 }
 639
 640 void MyFrame::OnPauseThread(wxCommandEvent& WXUNUSED(event) )
 641 {
 642     wxCriticalSectionLocker enter(wxGetApp().m_critsect);
 643
 644     // pause last running thread
 645     int n = wxGetApp().m_threads.Count() - 1;
 646     while ( n >= 0 && !wxGetApp().m_threads[n]->IsRunning() )
 647         n--;
 648
 649     if ( n < 0 )
 650     {
 651         wxLogError(wxT("No thread to pause!"));
 652     }
 653     else
 654     {
 655         wxGetApp().m_threads[n]->Pause();
 656
 657 #if wxUSE_STATUSBAR
 658         SetStatusText(wxT("Thread paused."), 1);
 659 #endif // wxUSE_STATUSBAR
 660     }
 661 }
 662
 663 void MyFrame::OnIdle(wxIdleEvent& event)
 664 {
 665     UpdateThreadStatus();
 666
 667     event.Skip();
 668 }
 669
 670 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event) )
 671 {
 672     Close(true);
 673 }
 674
 675 void MyFrame::OnExecMain(wxCommandEvent& WXUNUSED(event))
 676 {
 677     wxString cmd = wxGetTextFromUser("Please enter the command to execute",
 678                                      "Enter command",
 679 #ifdef __WXMSW__
 680                                      "notepad",
 681 #else
 682                                      "/bin/echo \"Message from another process\"",
 683 #endif
 684                                      this);
 685     if (cmd.IsEmpty())
 686         return;     // user clicked cancel
 687
 688     wxLogMessage(wxT("The exit code from the main program is %ld"),
 689                  EXEC(cmd));
 690 }
 691
 692 void MyFrame::OnShowCPUs(wxCommandEvent& WXUNUSED(event))
 693 {
 694     wxString msg;
 695
 696     int nCPUs = wxThread::GetCPUCount();
 697     switch ( nCPUs )
 698     {
 699         case -1:
 700             msg = wxT("Unknown number of CPUs");
 701             break;
 702
 703         case 0:
 704             msg = wxT("WARNING: you're running without any CPUs!");
 705             break;
 706
 707         case 1:
 708             msg = wxT("This system only has one CPU.");
 709             break;
 710
 711         default:
 712             msg.Printf(wxT("This system has %d CPUs"), nCPUs);
 713     }
 714
 715     wxLogMessage(msg);
 716 }
 717
 718 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event) )
 719 {
 720     wxMessageDialog dialog(this,
 721                            wxT("wxWidgets multithreaded application sample\n")
 722                            wxT("(c) 1998 Julian Smart, Guilhem Lavaux\n")
 723                            wxT("(c) 2000 Robert Roebling\n")
 724                            wxT("(c) 1999,2009 Vadim Zeitlin"),
 725                            wxT("About wxThread sample"),
 726                            wxOK | wxICON_INFORMATION);
 727
 728     dialog.ShowModal();
 729 }
 730
 731 void MyFrame::OnClear(wxCommandEvent& WXUNUSED(event))
 732 {
 733     m_txtctrl->Clear();
 734 }
 735
 736 void MyFrame::OnUpdateWorker(wxUpdateUIEvent& event)
 737 {
 738     event.Enable( m_dlgProgress == NULL );
 739 }
 740
 741 void MyFrame::OnStartWorker(wxCommandEvent& WXUNUSED(event))
 742 {
 743     MyWorkerThread *thread = new MyWorkerThread(this);
 744
 745     if ( thread->Create() != wxTHREAD_NO_ERROR )
 746     {
 747         wxLogError(wxT("Can't create thread!"));
 748         return;
 749     }
 750
 751     m_dlgProgress = new wxProgressDialog
 752                         (
 753                          wxT("Progress dialog"),
 754                          wxT("Wait until the thread terminates or press [Cancel]"),
 755                          100,
 756                          this,
 757                          wxPD_CAN_ABORT |
 758                          wxPD_APP_MODAL |
 759                          wxPD_ELAPSED_TIME |
 760                          wxPD_ESTIMATED_TIME |
 761                          wxPD_REMAINING_TIME
 762                         );
 763
 764     // thread is not running yet, no need for crit sect
 765     m_cancelled = false;
 766
 767     thread->Run();
 768 }
 769
 770 void MyFrame::OnWorkerEvent(wxThreadEvent& event)
 771 {
 772     int n = event.GetInt();
 773     if ( n == -1 )
 774     {
 775         m_dlgProgress->Destroy();
 776         m_dlgProgress = (wxProgressDialog *)NULL;
 777
 778         // the dialog is aborted because the event came from another thread, so
 779         // we may need to wake up the main event loop for the dialog to be
 780         // really closed
 781         wxWakeUpIdle();
 782     }
 783     else
 784     {
 785         if ( !m_dlgProgress->Update(n) )
 786         {
 787             wxCriticalSectionLocker lock(m_csCancelled);
 788
 789             m_cancelled = true;
 790         }
 791     }
 792 }
 793
 794 void MyFrame::OnStartGUIThread(wxCommandEvent& WXUNUSED(event))
 795 {
 796     // we use this to check that disabling logging only affects the main thread
 797     // but the messages from the worker thread will still be logged
 798     wxLogNull noLog;
 799     wxLogMessage("You shouldn't see this message because of wxLogNull");
 800
 801     MyImageDialog dlg(this);
 802
 803     dlg.ShowModal();
 804 }
 805
 806
 807 // ----------------------------------------------------------------------------
 808 // MyImageDialog
 809 // ----------------------------------------------------------------------------
 810
 811 BEGIN_EVENT_TABLE(MyImageDialog, wxDialog)
 812     EVT_THREAD(GUITHREAD_EVENT, MyImageDialog::OnGUIThreadEvent)
 813     EVT_PAINT(MyImageDialog::OnPaint)
 814 END_EVENT_TABLE()
 815
 816 MyImageDialog::MyImageDialog(wxFrame *parent)
 817     : wxDialog(parent, wxID_ANY, "Image created by a secondary thread",
 818                wxDefaultPosition, wxSize(GUITHREAD_BMP_SIZE,GUITHREAD_BMP_SIZE)*1.5, wxDEFAULT_DIALOG_STYLE),
 819       m_thread(this)
 820 {
 821     m_nCurrentProgress = 0;
 822
 823     CentreOnScreen();
 824
 825     // NOTE: no need to lock m_csBmp until the thread isn't started:
 826
 827     // create the bitmap
 828     if (!m_bmp.Create(GUITHREAD_BMP_SIZE,GUITHREAD_BMP_SIZE) || !m_bmp.IsOk())
 829     {
 830         wxLogError("Couldn't create the bitmap!");
 831         return;
 832     }
 833
 834     // clean it
 835     wxMemoryDC dc(m_bmp);
 836     dc.SetBackground(*wxBLACK_BRUSH);
 837     dc.Clear();
 838
 839     // draw the bitmap from a secondary thread
 840     if ( m_thread.Create() != wxTHREAD_NO_ERROR ||
 841          m_thread.Run() != wxTHREAD_NO_ERROR )
 842     {
 843         wxLogError(wxT("Can't create/run thread!"));
 844         return;
 845     }
 846 }
 847
 848 MyImageDialog::~MyImageDialog()
 849 {
 850     // in case our thread is still running and for some reason we are destroyed,
 851     // do wait for the thread to complete as it assumes that its MyImageDialog
 852     // pointer is always valid
 853     m_thread.Delete();
 854 }
 855
 856 void MyImageDialog::OnGUIThreadEvent(wxThreadEvent& event)
 857 {
 858     m_nCurrentProgress = int(((float)event.GetInt()*100)/GUITHREAD_NUM_UPDATES);
 859
 860     Refresh();
 861 }
 862
 863 void MyImageDialog::OnPaint(wxPaintEvent& WXUNUSED(evt))
 864 {
 865     wxPaintDC dc(this);
 866
 867     const wxSize& sz = dc.GetSize();
 868
 869     {
 870         // paint the bitmap
 871         wxCriticalSectionLocker locker(m_csBmp);
 872         dc.DrawBitmap(m_bmp, (sz.GetWidth()-GUITHREAD_BMP_SIZE)/2,
 873                              (sz.GetHeight()-GUITHREAD_BMP_SIZE)/2);
 874     }
 875
 876     // paint a sort of progress bar with a 10px border:
 877     dc.SetBrush(*wxRED_BRUSH);
 878     dc.DrawRectangle(10,10, m_nCurrentProgress*(sz.GetWidth()-20)/100,30);
 879     dc.SetTextForeground(*wxBLUE);
 880     dc.DrawText(wxString::Format("%d%%", m_nCurrentProgress),
 881                 (sz.GetWidth()-dc.GetCharWidth()*2)/2,
 882                 25-dc.GetCharHeight()/2);
 883 }
 884
 885 // ----------------------------------------------------------------------------
 886 // MyThread
 887 // ----------------------------------------------------------------------------
 888
 889 MyThread::MyThread()
 890         : wxThread()
 891 {
 892     m_count = 0;
 893 }
 894
 895 MyThread::~MyThread()
 896 {
 897     wxCriticalSectionLocker locker(wxGetApp().m_critsect);
 898
 899     wxArrayThread& threads = wxGetApp().m_threads;
 900     threads.Remove(this);
 901
 902     if ( threads.IsEmpty() )
 903     {
 904         // signal the main thread that there are no more threads left if it is
 905         // waiting for us
 906         if ( wxGetApp().m_shuttingDown )
 907         {
 908             wxGetApp().m_shuttingDown = false;
 909
 910             wxGetApp().m_semAllDone.Post();
 911         }
 912     }
 913 }
 914
 915 wxThread::ExitCode MyThread::Entry()
 916 {
 917     wxLogMessage("Thread started (priority = %u).", GetPriority());
 918
 919     for ( m_count = 0; m_count < 10; m_count++ )
 920     {
 921         // check if the application is shutting down: in this case all threads
 922         // should stop a.s.a.p.
 923         {
 924             wxCriticalSectionLocker locker(wxGetApp().m_critsect);
 925             if ( wxGetApp().m_shuttingDown )
 926                 return NULL;
 927         }
 928
 929         // check if just this thread was asked to exit
 930         if ( TestDestroy() )
 931             break;
 932
 933         wxLogMessage("Thread progress: %u", m_count);
 934
 935         // wxSleep() can't be called from non-GUI thread!
 936         wxThread::Sleep(1000);
 937     }
 938
 939     wxLogMessage("Thread finished.");
 940
 941     return NULL;
 942 }
 943
 944
 945 // ----------------------------------------------------------------------------
 946 // MyWorkerThread
 947 // ----------------------------------------------------------------------------
 948
 949 // define this symbol to 1 to test if the YieldFor() call in the wxProgressDialog::Update
 950 // function provokes a race condition in which the second wxThreadEvent posted by
 951 // MyWorkerThread::Entry is processed by the YieldFor() call of wxProgressDialog::Update
 952 // and results in the destruction of the progress dialog itself, resulting in a crash later.
 953 #define TEST_YIELD_RACE_CONDITION       0
 954
 955 MyWorkerThread::MyWorkerThread(MyFrame *frame)
 956         : wxThread()
 957 {
 958     m_frame = frame;
 959     m_count = 0;
 960 }
 961
 962 void MyWorkerThread::OnExit()
 963 {
 964 }
 965
 966 wxThread::ExitCode MyWorkerThread::Entry()
 967 {
 968 #if TEST_YIELD_RACE_CONDITION
 969     if ( TestDestroy() )
 970         return NULL;
 971
 972     wxThreadEvent event( wxEVT_COMMAND_THREAD, WORKER_EVENT );
 973
 974     event.SetInt( 50 );
 975     wxQueueEvent( m_frame, event.Clone() );
 976
 977     event.SetInt(-1);
 978     wxQueueEvent( m_frame, event.Clone() );
 979 #else
 980     for ( m_count = 0; !m_frame->Cancelled() && (m_count < 100); m_count++ )
 981     {
 982         // check if we were asked to exit
 983         if ( TestDestroy() )
 984             break;
 985
 986         // create any type of command event here
 987         wxThreadEvent event( wxEVT_COMMAND_THREAD, WORKER_EVENT );
 988         event.SetInt( m_count );
 989
 990         // send in a thread-safe way
 991         wxQueueEvent( m_frame, event.Clone() );
 992
 993         wxMilliSleep(200);
 994     }
 995
 996     wxThreadEvent event( wxEVT_COMMAND_THREAD, WORKER_EVENT );
 997     event.SetInt(-1); // that's all
 998     wxQueueEvent( m_frame, event.Clone() );
 999 #endif
1000
1001     return NULL;
1002 }
1003
1004
1005 // ----------------------------------------------------------------------------
1006 // MyGUIThread
1007 // ----------------------------------------------------------------------------
1008
1009 wxThread::ExitCode MyGUIThread::Entry()
1010 {
1011     // uncomment this to check that disabling logging here does disable it for
1012     // this thread -- but not the main one if you also comment out wxLogNull
1013     // line in MyFrame::OnStartGUIThread()
1014     //wxLogNull noLog;
1015
1016     // this goes to the main window
1017     wxLogMessage("GUI thread starting");
1018
1019     // use a thread-specific log target for this thread to show that its
1020     // messages don't appear in the main window while it runs
1021     wxLogBuffer logBuf;
1022     wxLog::SetThreadActiveTarget(&logBuf);
1023
1024     for (int i=0; i<GUITHREAD_NUM_UPDATES && !TestDestroy(); i++)
1025     {
1026         // inform the GUI toolkit that we're going to use GUI functions
1027         // from a secondary thread:
1028         wxMutexGuiEnter();
1029
1030         {
1031             wxCriticalSectionLocker lock(m_dlg->m_csBmp);
1032
1033             // draw some more stuff on the bitmap
1034             wxMemoryDC dc(m_dlg->m_bmp);
1035             dc.SetBrush((i%2)==0 ? *wxBLUE_BRUSH : *wxGREEN_BRUSH);
1036             dc.DrawRectangle(rand()%GUITHREAD_BMP_SIZE, rand()%GUITHREAD_BMP_SIZE, 30, 30);
1037
1038             // simulate long drawing time:
1039             wxMilliSleep(200);
1040         }
1041
1042         // if we don't release the GUI mutex the MyImageDialog won't be able to refresh
1043         wxMutexGuiLeave();
1044
1045         // notify the dialog that another piece of our masterpiece is complete:
1046         wxThreadEvent event( wxEVT_COMMAND_THREAD, GUITHREAD_EVENT );
1047         event.SetInt(i+1);
1048         wxQueueEvent( m_dlg, event.Clone() );
1049
1050         if ( !((i + 1) % 10) )
1051         {
1052             // this message will go to the buffer
1053             wxLogMessage("Step #%d.", i + 1);
1054         }
1055
1056         // give the main thread the time to refresh before we lock the GUI mutex again
1057         // FIXME: find a better way to do this!
1058         wxMilliSleep(100);
1059     }
1060
1061     // now remove the thread-specific thread target
1062     wxLog::SetThreadActiveTarget(NULL);
1063
1064     // so that this goes to the main window again
1065     wxLogMessage("GUI thread finished.");
1066
1067     return (ExitCode)0;
1068 }