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