X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/cd431efcdfaa08e1fb87a8f4d74a2a0bb8de8ed7..78612fa68fdeb01b2cb0fa8b2b89fc8924bb71ff:/samples/thread/thread.cpp diff --git a/samples/thread/thread.cpp b/samples/thread/thread.cpp index 87c0e07e02..f5ec942d81 100644 --- a/samples/thread/thread.cpp +++ b/samples/thread/thread.cpp @@ -53,20 +53,18 @@ public: virtual bool OnInit(); -public: + // critical section protects access to all of the fields below + wxCriticalSection m_critsect; + // all the threads currently alive - as soon as the thread terminates, it's // removed from the array wxArrayThread m_threads; - // crit section protects access to all of the arrays below - wxCriticalSection m_critsect; - // semaphore used to wait for the threads to exit, see MyFrame::OnQuit() wxSemaphore m_semAllDone; - // the last exiting thread should post to m_semAllDone if this is true - // (protected by the same m_critsect) - bool m_waitingUntilAllDone; + // indicates that we're shutting down and all threads should exit + bool m_shuttingDown; }; // Create a new application object @@ -80,14 +78,23 @@ public: MyFrame(wxFrame *frame, const wxString& title, int x, int y, int w, int h); virtual ~MyFrame(); - // operations - void WriteText(const wxString& text) { m_txtctrl->WriteText(text); } + // this function is MT-safe, i.e. it can be called from worker threads + // safely without any additional locking + void LogThreadMessage(const wxString& text) + { + wxCriticalSectionLocker lock(m_csMessages); + m_messages.push_back(text); + + // as we effectively log the messages from the idle event handler, + // ensure it's going to be called now that we have some messages to log + wxWakeUpIdle(); + } // accessors for MyWorkerThread (called in its context!) bool Cancelled(); -protected: - // callbacks +private: + // event handlers void OnQuit(wxCommandEvent& event); void OnClear(wxCommandEvent& event); @@ -98,7 +105,7 @@ protected: void OnResumeThread(wxCommandEvent& event); void OnStartWorker(wxCommandEvent& event); - void OnWorkerEvent(wxCommandEvent& event); + void OnWorkerEvent(wxThreadEvent& event); void OnUpdateWorker(wxUpdateUIEvent& event); void OnExecMain(wxCommandEvent& event); @@ -109,15 +116,27 @@ protected: void OnIdle(wxIdleEvent &event); -private: // helper function - creates a new thread (but doesn't run it) MyThread *CreateThread(); + // update display in our status bar: called during idle handling + void UpdateThreadStatus(); + + // log the messages queued by LogThreadMessage() + void DoLogThreadMessages(); + + // just some place to put our messages in wxTextCtrl *m_txtctrl; + // the array of pending messages to be displayed and the critical section + // protecting it + wxArrayString m_messages; + wxCriticalSection m_csMessages; + // remember the number of running threads and total number of threads - size_t m_nRunning, m_nCount; + size_t m_nRunning, + m_nCount; // the progress dialog which we show while worker thread is running wxProgressDialog *m_dlgProgress; @@ -150,7 +169,7 @@ enum THREAD_SHOWCPUS, - WORKER_EVENT // this one gets sent from the worker thread + WORKER_EVENT = wxID_HIGHEST+1 // this one gets sent from the worker thread }; // ---------------------------------------------------------------------------- @@ -161,16 +180,16 @@ class MyThread : public wxThread { public: MyThread(MyFrame *frame); + virtual ~MyThread(); // thread execution starts here virtual void *Entry(); - // called when the thread exits - whether it terminates normally or is - // stopped with Delete() (but not when it is Kill()ed!) - virtual void OnExit(); - - // write something to the text control - void WriteText(const wxString& text); + // write something to the text control in the main frame + void WriteText(const wxString& text) + { + m_frame->LogThreadMessage(text); + } public: unsigned m_count; @@ -184,22 +203,7 @@ MyThread::MyThread(MyFrame *frame) m_frame = frame; } -void MyThread::WriteText(const wxString& text) -{ - wxString msg; - - // before doing any GUI calls we must ensure that this thread is the only - // one doing it! - - wxMutexGuiEnter(); - - msg << text; - m_frame->WriteText(msg); - - wxMutexGuiLeave(); -} - -void MyThread::OnExit() +MyThread::~MyThread() { wxCriticalSectionLocker locker(wxGetApp().m_critsect); @@ -210,9 +214,9 @@ void MyThread::OnExit() { // signal the main thread that there are no more threads left if it is // waiting for us - if ( wxGetApp().m_waitingUntilAllDone ) + if ( wxGetApp().m_shuttingDown ) { - wxGetApp().m_waitingUntilAllDone = false; + wxGetApp().m_shuttingDown = false; wxGetApp().m_semAllDone.Post(); } @@ -230,7 +234,15 @@ void *MyThread::Entry() for ( m_count = 0; m_count < 10; m_count++ ) { - // check if we were asked to exit + // check if the application is shutting down: in this case all threads + // should stop a.s.a.p. + { + wxCriticalSectionLocker locker(wxGetApp().m_critsect); + if ( wxGetApp().m_shuttingDown ) + return NULL; + } + + // check if just this thread was asked to exit if ( TestDestroy() ) break; @@ -280,8 +292,22 @@ void MyWorkerThread::OnExit() { } +#define TEST_YIELD_RACE_CONDITION 0 + void *MyWorkerThread::Entry() { +#if TEST_YIELD_RACE_CONDITION + if ( TestDestroy() ) + return NULL; + + wxThreadEvent event( wxEVT_COMMAND_THREAD, WORKER_EVENT ); + + event.SetInt( 50 ); + wxQueueEvent( m_frame, new wxThreadEvent(event) ); + + event.SetInt(-1); + wxQueueEvent( m_frame, new wxThreadEvent(event) ); +#else for ( m_count = 0; !m_frame->Cancelled() && (m_count < 100); m_count++ ) { // check if we were asked to exit @@ -289,19 +315,19 @@ void *MyWorkerThread::Entry() break; // create any type of command event here - wxCommandEvent event( wxEVT_COMMAND_MENU_SELECTED, WORKER_EVENT ); + wxThreadEvent event( wxEVT_COMMAND_THREAD, WORKER_EVENT ); event.SetInt( m_count ); // send in a thread-safe way - wxPostEvent( m_frame, event ); + wxQueueEvent( m_frame, new wxThreadEvent(event) ); - // wxSleep() can't be called from non-main thread! - wxThread::Sleep(200); + wxMilliSleep(200); } - wxCommandEvent event( wxEVT_COMMAND_MENU_SELECTED, WORKER_EVENT ); + wxThreadEvent event( wxEVT_COMMAND_THREAD, WORKER_EVENT ); event.SetInt(-1); // that's all - wxPostEvent( m_frame, event ); + wxQueueEvent( m_frame, new wxThreadEvent(event) ); +#endif return NULL; } @@ -349,15 +375,15 @@ BEGIN_EVENT_TABLE(MyFrame, wxFrame) EVT_UPDATE_UI(THREAD_START_WORKER, MyFrame::OnUpdateWorker) EVT_MENU(THREAD_START_WORKER, MyFrame::OnStartWorker) - EVT_MENU(WORKER_EVENT, MyFrame::OnWorkerEvent) + + EVT_THREAD(WORKER_EVENT, MyFrame::OnWorkerEvent) EVT_IDLE(MyFrame::OnIdle) END_EVENT_TABLE() MyApp::MyApp() - : m_semAllDone() { - m_waitingUntilAllDone = false; + m_shuttingDown = false; } // `Main program' equivalent, creating windows and returning main app frame @@ -406,7 +432,7 @@ bool MyApp::OnInit() menuBar->Append(menuHelp, _T("&Help")); frame->SetMenuBar(menuBar); - + // Show the frame frame->Show(true); @@ -421,7 +447,7 @@ MyFrame::MyFrame(wxFrame *frame, const wxString& title, : wxFrame(frame, wxID_ANY, title, wxPoint(x, y), wxSize(w, h)) { SetIcon(wxIcon(sample_xpm)); - + m_nRunning = m_nCount = 0; m_dlgProgress = (wxProgressDialog *)NULL; @@ -432,7 +458,6 @@ MyFrame::MyFrame(wxFrame *frame, const wxString& title, m_txtctrl = new wxTextCtrl(this, wxID_ANY, _T(""), wxPoint(0, 0), wxSize(0, 0), wxTE_MULTILINE | wxTE_READONLY); - } MyFrame::~MyFrame() @@ -444,40 +469,23 @@ MyFrame::~MyFrame() // tell all the threads to terminate: note that they can't terminate while // we're deleting them because they will block in their OnExit() -- this is // important as otherwise we might access invalid array elements - wxThread *thread; - - wxGetApp().m_critsect.Enter(); - - // check if we have any threads running first - const wxArrayThread& threads = wxGetApp().m_threads; - size_t count = threads.GetCount(); - if ( count ) { - // set the flag for MyThread::OnExit() - wxGetApp().m_waitingUntilAllDone = true; + wxCriticalSectionLocker locker(wxGetApp().m_critsect); - // stop all threads - while ( ! threads.IsEmpty() ) - { - thread = threads.Last(); - - wxGetApp().m_critsect.Leave(); + // check if we have any threads running first + const wxArrayThread& threads = wxGetApp().m_threads; + size_t count = threads.GetCount(); - thread->Delete(); + if ( !count ) + return; - wxGetApp().m_critsect.Enter(); - } + // set the flag indicating that all threads should exit + wxGetApp().m_shuttingDown = true; } - wxGetApp().m_critsect.Leave(); - - if ( count ) - { - // now wait for them to really terminate - wxGetApp().m_semAllDone.Wait(); - } - //else: no threads to terminate, no condition to wait for + // now wait for them to really terminate + wxGetApp().m_semAllDone.Wait(); } MyThread *MyFrame::CreateThread() @@ -559,28 +567,19 @@ void MyFrame::OnStartThread(wxCommandEvent& WXUNUSED(event) ) void MyFrame::OnStopThread(wxCommandEvent& WXUNUSED(event) ) { - wxGetApp().m_critsect.Enter(); + wxCriticalSectionLocker enter(wxGetApp().m_critsect); // stop the last thread if ( wxGetApp().m_threads.IsEmpty() ) { wxLogError(wxT("No thread to stop!")); - - wxGetApp().m_critsect.Leave(); } else { - wxThread *thread = wxGetApp().m_threads.Last(); - - // it's important to leave critical section before calling Delete() - // because delete will (implicitly) call OnExit() which also tries - // to enter the same crit section - would dead lock. - wxGetApp().m_critsect.Leave(); - - thread->Delete(); + wxGetApp().m_threads.Last()->Delete(); #if wxUSE_STATUSBAR - SetStatusText(_T("Thread stopped."), 1); + SetStatusText(_T("Last thread stopped."), 1); #endif // wxUSE_STATUSBAR } } @@ -631,8 +630,29 @@ void MyFrame::OnPauseThread(wxCommandEvent& WXUNUSED(event) ) } } -// set the frame title indicating the current number of threads void MyFrame::OnIdle(wxIdleEvent& event) +{ + DoLogThreadMessages(); + + UpdateThreadStatus(); + + event.Skip(); +} + +void MyFrame::DoLogThreadMessages() +{ + wxCriticalSectionLocker lock(m_csMessages); + + const size_t count = m_messages.size(); + for ( size_t n = 0; n < count; n++ ) + { + m_txtctrl->AppendText(m_messages[n]); + } + + m_messages.clear(); +} + +void MyFrame::UpdateThreadStatus() { wxCriticalSectionLocker enter(wxGetApp().m_critsect); @@ -653,8 +673,6 @@ void MyFrame::OnIdle(wxIdleEvent& event) wxLogStatus(this, wxT("%u threads total, %u running."), unsigned(nCount), unsigned(nRunning)); } //else: avoid flicker - don't print anything - - event.Skip(); } void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event) ) @@ -755,13 +773,8 @@ void MyFrame::OnStartWorker(wxCommandEvent& WXUNUSED(event)) thread->Run(); } -void MyFrame::OnWorkerEvent(wxCommandEvent& event) +void MyFrame::OnWorkerEvent(wxThreadEvent& event) { -#if 0 - WriteText( _T("Got message from worker thread: ") ); - WriteText( event.GetString() ); - WriteText( _T("\n") ); -#else int n = event.GetInt(); if ( n == -1 ) { @@ -782,7 +795,6 @@ void MyFrame::OnWorkerEvent(wxCommandEvent& event) m_cancelled = true; } } -#endif } bool MyFrame::Cancelled()