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wxWidgets/samples/thread/thread.cpp

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/////////////////////////////////////////////////////////////////////////////
// Name: thread.cpp
// Purpose: wxWidgets thread sample
// Author: Guilhem Lavaux, Vadim Zeitlin
// Modified by:
// Created: 06/16/98
// RCS-ID: $Id$
// Copyright: (c) 1998-2002 wxWidgets team
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
// For compilers that support precompilation, includes "wx/wx.h".
#include "wx/wxprec.h"
#ifdef __BORLANDC__
#pragma hdrstop
#endif
#ifndef WX_PRECOMP
#include "wx/wx.h"
#endif
#if !wxUSE_THREADS
#error "This sample requires thread support!"
#endif // wxUSE_THREADS
#include "wx/thread.h"
#include "wx/dynarray.h"
#include "wx/numdlg.h"
#include "wx/progdlg.h"
#include "../sample.xpm"
// define this to use wxExecute in the exec tests, otherwise just use system
#define USE_EXECUTE
#ifdef USE_EXECUTE
#define EXEC(cmd) wxExecute((cmd), wxEXEC_SYNC)
#else
#define EXEC(cmd) system(cmd)
#endif
class MyThread;
WX_DEFINE_ARRAY_PTR(wxThread *, wxArrayThread);
// Define a new application type
class MyApp : public wxApp
{
public:
MyApp();
virtual ~MyApp(){};
virtual bool OnInit();
// 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;
// semaphore used to wait for the threads to exit, see MyFrame::OnQuit()
wxSemaphore m_semAllDone;
// indicates that we're shutting down and all threads should exit
bool m_shuttingDown;
};
// Create a new application object
IMPLEMENT_APP(MyApp)
// Define a new frame type
class MyFrame: public wxFrame
{
public:
// ctor
MyFrame(wxFrame *frame, const wxString& title, int x, int y, int w, int h);
virtual ~MyFrame();
// 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();
private:
// event handlers
void OnQuit(wxCommandEvent& event);
void OnClear(wxCommandEvent& event);
void OnStartThread(wxCommandEvent& event);
void OnStartThreads(wxCommandEvent& event);
void OnStopThread(wxCommandEvent& event);
void OnPauseThread(wxCommandEvent& event);
void OnResumeThread(wxCommandEvent& event);
void OnStartWorker(wxCommandEvent& event);
void OnWorkerEvent(wxCommandEvent& event);
void OnUpdateWorker(wxUpdateUIEvent& event);
void OnExecMain(wxCommandEvent& event);
void OnExecThread(wxCommandEvent& event);
void OnShowCPUs(wxCommandEvent& event);
void OnAbout(wxCommandEvent& event);
void OnIdle(wxIdleEvent &event);
// 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;
// the progress dialog which we show while worker thread is running
wxProgressDialog *m_dlgProgress;
// was the worker thread cancelled by user?
bool m_cancelled;
// protects m_cancelled
wxCriticalSection m_critsectWork;
DECLARE_EVENT_TABLE()
};
// ID for the menu commands
enum
{
THREAD_QUIT = wxID_EXIT,
THREAD_ABOUT = wxID_ABOUT,
THREAD_TEXT = 101,
THREAD_CLEAR,
THREAD_START_THREAD = 201,
THREAD_START_THREADS,
THREAD_STOP_THREAD,
THREAD_PAUSE_THREAD,
THREAD_RESUME_THREAD,
THREAD_START_WORKER,
THREAD_EXEC_MAIN,
THREAD_EXEC_THREAD,
THREAD_SHOWCPUS,
WORKER_EVENT // this one gets sent from the worker thread
};
// ----------------------------------------------------------------------------
// GUI thread
// ----------------------------------------------------------------------------
class MyThread : public wxThread
{
public:
MyThread(MyFrame *frame);
virtual ~MyThread();
// thread execution starts here
virtual void *Entry();
// write something to the text control in the main frame
void WriteText(const wxString& text)
{
m_frame->LogThreadMessage(text);
}
public:
unsigned m_count;
MyFrame *m_frame;
};
MyThread::MyThread(MyFrame *frame)
: wxThread()
{
m_count = 0;
m_frame = frame;
}
MyThread::~MyThread()
{
wxCriticalSectionLocker locker(wxGetApp().m_critsect);
wxArrayThread& threads = wxGetApp().m_threads;
threads.Remove(this);
if ( threads.IsEmpty() )
{
// signal the main thread that there are no more threads left if it is
// waiting for us
if ( wxGetApp().m_shuttingDown )
{
wxGetApp().m_shuttingDown = false;
wxGetApp().m_semAllDone.Post();
}
}
}
void *MyThread::Entry()
{
wxString text;
text.Printf(wxT("Thread 0x%lx started (priority = %u).\n"),
GetId(), GetPriority());
WriteText(text);
// wxLogMessage(text); -- test wxLog thread safeness
for ( m_count = 0; m_count < 10; m_count++ )
{
// 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;
text.Printf(wxT("[%u] Thread 0x%lx here.\n"), m_count, GetId());
WriteText(text);
// wxSleep() can't be called from non-GUI thread!
wxThread::Sleep(1000);
}
text.Printf(wxT("Thread 0x%lx finished.\n"), GetId());
WriteText(text);
// wxLogMessage(text); -- test wxLog thread safeness
return NULL;
}
// ----------------------------------------------------------------------------
// worker thread
// ----------------------------------------------------------------------------
class MyWorkerThread : public wxThread
{
public:
MyWorkerThread(MyFrame *frame);
// 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();
public:
MyFrame *m_frame;
unsigned m_count;
};
MyWorkerThread::MyWorkerThread(MyFrame *frame)
: wxThread()
{
m_frame = frame;
m_count = 0;
}
void MyWorkerThread::OnExit()
{
}
void *MyWorkerThread::Entry()
{
for ( m_count = 0; !m_frame->Cancelled() && (m_count < 100); m_count++ )
{
// check if we were asked to exit
if ( TestDestroy() )
break;
// create any type of command event here
wxCommandEvent event( wxEVT_COMMAND_MENU_SELECTED, WORKER_EVENT );
event.SetInt( m_count );
// send in a thread-safe way
wxPostEvent( m_frame, event );
wxMilliSleep(200);
}
wxCommandEvent event( wxEVT_COMMAND_MENU_SELECTED, WORKER_EVENT );
event.SetInt(-1); // that's all
wxPostEvent( m_frame, event );
return NULL;
}
// ----------------------------------------------------------------------------
// a thread which simply calls wxExecute
// ----------------------------------------------------------------------------
class MyExecThread : public wxThread
{
public:
MyExecThread(const wxChar *command) : wxThread(wxTHREAD_JOINABLE),
m_command(command)
{
Create();
}
virtual ExitCode Entry()
{
return wxUIntToPtr(EXEC(m_command));
}
private:
wxString m_command;
};
// ----------------------------------------------------------------------------
// implementation
// ----------------------------------------------------------------------------
BEGIN_EVENT_TABLE(MyFrame, wxFrame)
EVT_MENU(THREAD_QUIT, MyFrame::OnQuit)
EVT_MENU(THREAD_CLEAR, MyFrame::OnClear)
EVT_MENU(THREAD_START_THREAD, MyFrame::OnStartThread)
EVT_MENU(THREAD_START_THREADS, MyFrame::OnStartThreads)
EVT_MENU(THREAD_STOP_THREAD, MyFrame::OnStopThread)
EVT_MENU(THREAD_PAUSE_THREAD, MyFrame::OnPauseThread)
EVT_MENU(THREAD_RESUME_THREAD, MyFrame::OnResumeThread)
EVT_MENU(THREAD_EXEC_MAIN, MyFrame::OnExecMain)
EVT_MENU(THREAD_EXEC_THREAD, MyFrame::OnExecThread)
EVT_MENU(THREAD_SHOWCPUS, MyFrame::OnShowCPUs)
EVT_MENU(THREAD_ABOUT, MyFrame::OnAbout)
EVT_UPDATE_UI(THREAD_START_WORKER, MyFrame::OnUpdateWorker)
EVT_MENU(THREAD_START_WORKER, MyFrame::OnStartWorker)
EVT_MENU(WORKER_EVENT, MyFrame::OnWorkerEvent)
EVT_IDLE(MyFrame::OnIdle)
END_EVENT_TABLE()
MyApp::MyApp()
{
m_shuttingDown = false;
}
// `Main program' equivalent, creating windows and returning main app frame
bool MyApp::OnInit()
{
if ( !wxApp::OnInit() )
return false;
// uncomment this to get some debugging messages from the trace code
// on the console (or just set WXTRACE env variable to include "thread")
//wxLog::AddTraceMask("thread");
// Create the main frame window
MyFrame *frame = new MyFrame((wxFrame *)NULL, _T("wxWidgets threads sample"),
50, 50, 450, 340);
// Make a menubar
wxMenuBar *menuBar = new wxMenuBar;
wxMenu *menuFile = new wxMenu;
menuFile->Append(THREAD_CLEAR, _T("&Clear log\tCtrl-L"));
menuFile->AppendSeparator();
menuFile->Append(THREAD_QUIT, _T("E&xit\tAlt-X"));
menuBar->Append(menuFile, _T("&File"));
wxMenu *menuThread = new wxMenu;
menuThread->Append(THREAD_START_THREAD, _T("&Start a new thread\tCtrl-N"));
menuThread->Append(THREAD_START_THREADS, _T("Start &many threads at once"));
menuThread->Append(THREAD_STOP_THREAD, _T("S&top a running thread\tCtrl-S"));
menuThread->AppendSeparator();
menuThread->Append(THREAD_PAUSE_THREAD, _T("&Pause a running thread\tCtrl-P"));
menuThread->Append(THREAD_RESUME_THREAD, _T("&Resume suspended thread\tCtrl-R"));
menuThread->AppendSeparator();
menuThread->Append(THREAD_START_WORKER, _T("Start &worker thread\tCtrl-W"));
menuBar->Append(menuThread, _T("&Thread"));
wxMenu *menuExec = new wxMenu;
menuExec->Append(THREAD_EXEC_MAIN, _T("&Launch a program from main thread\tF5"));
menuExec->Append(THREAD_EXEC_THREAD, _T("L&aunch a program from a thread\tCtrl-F5"));
menuBar->Append(menuExec, _T("&Execute"));
wxMenu *menuHelp = new wxMenu;
menuHelp->Append(THREAD_SHOWCPUS, _T("&Show CPU count"));
menuHelp->AppendSeparator();
menuHelp->Append(THREAD_ABOUT, _T("&About..."));
menuBar->Append(menuHelp, _T("&Help"));
frame->SetMenuBar(menuBar);
// Show the frame
frame->Show(true);
SetTopWindow(frame);
return true;
}
// My frame constructor
MyFrame::MyFrame(wxFrame *frame, const wxString& title,
int x, int y, int w, int h)
: wxFrame(frame, wxID_ANY, title, wxPoint(x, y), wxSize(w, h))
{
SetIcon(wxIcon(sample_xpm));
m_nRunning = m_nCount = 0;
m_dlgProgress = (wxProgressDialog *)NULL;
#if wxUSE_STATUSBAR
CreateStatusBar(2);
#endif // wxUSE_STATUSBAR
m_txtctrl = new wxTextCtrl(this, wxID_ANY, _T(""), wxPoint(0, 0), wxSize(0, 0),
wxTE_MULTILINE | wxTE_READONLY);
}
MyFrame::~MyFrame()
{
// NB: although the OS will terminate all the threads anyhow when the main
// one exits, it's good practice to do it ourselves -- even if it's not
// completely trivial in this example
// 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
{
wxCriticalSectionLocker locker(wxGetApp().m_critsect);
// check if we have any threads running first
const wxArrayThread& threads = wxGetApp().m_threads;
size_t count = threads.GetCount();
if ( !count )
return;
// set the flag indicating that all threads should exit
wxGetApp().m_shuttingDown = true;
}
// now wait for them to really terminate
wxGetApp().m_semAllDone.Wait();
}
MyThread *MyFrame::CreateThread()
{
MyThread *thread = new MyThread(this);
if ( thread->Create() != wxTHREAD_NO_ERROR )
{
wxLogError(wxT("Can't create thread!"));
}
wxCriticalSectionLocker enter(wxGetApp().m_critsect);
wxGetApp().m_threads.Add(thread);
return thread;
}
void MyFrame::OnStartThreads(wxCommandEvent& WXUNUSED(event) )
{
static long s_num;
s_num = wxGetNumberFromUser(_T("How many threads to start: "), _T(""),
_T("wxThread sample"), s_num, 1, 10000, this);
if ( s_num == -1 )
{
s_num = 10;
return;
}
unsigned count = unsigned(s_num), n;
wxArrayThread threads;
// first create them all...
for ( n = 0; n < count; n++ )
{
wxThread *thr = CreateThread();
// we want to show the effect of SetPriority(): the first thread will
// have the lowest priority, the second - the highest, all the rest
// the normal one
if ( n == 0 )
thr->SetPriority(WXTHREAD_MIN_PRIORITY);
else if ( n == 1 )
thr->SetPriority(WXTHREAD_MAX_PRIORITY);
else
thr->SetPriority(WXTHREAD_DEFAULT_PRIORITY);
threads.Add(thr);
}
#if wxUSE_STATUSBAR
wxString msg;
msg.Printf(wxT("%d new threads created."), count);
SetStatusText(msg, 1);
#endif // wxUSE_STATUSBAR
// ...and then start them
for ( n = 0; n < count; n++ )
{
threads[n]->Run();
}
}
void MyFrame::OnStartThread(wxCommandEvent& WXUNUSED(event) )
{
MyThread *thread = CreateThread();
if ( thread->Run() != wxTHREAD_NO_ERROR )
{
wxLogError(wxT("Can't start thread!"));
}
#if wxUSE_STATUSBAR
SetStatusText(_T("New thread started."), 1);
#endif // wxUSE_STATUSBAR
}
void MyFrame::OnStopThread(wxCommandEvent& WXUNUSED(event) )
{
wxCriticalSectionLocker enter(wxGetApp().m_critsect);
// stop the last thread
if ( wxGetApp().m_threads.IsEmpty() )
{
wxLogError(wxT("No thread to stop!"));
}
else
{
wxGetApp().m_threads.Last()->Delete();
#if wxUSE_STATUSBAR
SetStatusText(_T("Last thread stopped."), 1);
#endif // wxUSE_STATUSBAR
}
}
void MyFrame::OnResumeThread(wxCommandEvent& WXUNUSED(event) )
{
wxCriticalSectionLocker enter(wxGetApp().m_critsect);
// resume first suspended thread
size_t n = 0, count = wxGetApp().m_threads.Count();
while ( n < count && !wxGetApp().m_threads[n]->IsPaused() )
n++;
if ( n == count )
{
wxLogError(wxT("No thread to resume!"));
}
else
{
wxGetApp().m_threads[n]->Resume();
#if wxUSE_STATUSBAR
SetStatusText(_T("Thread resumed."), 1);
#endif // wxUSE_STATUSBAR
}
}
void MyFrame::OnPauseThread(wxCommandEvent& WXUNUSED(event) )
{
wxCriticalSectionLocker enter(wxGetApp().m_critsect);
// pause last running thread
int n = wxGetApp().m_threads.Count() - 1;
while ( n >= 0 && !wxGetApp().m_threads[n]->IsRunning() )
n--;
if ( n < 0 )
{
wxLogError(wxT("No thread to pause!"));
}
else
{
wxGetApp().m_threads[n]->Pause();
#if wxUSE_STATUSBAR
SetStatusText(_T("Thread paused."), 1);
#endif // wxUSE_STATUSBAR
}
}
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);
// update the counts of running/total threads
size_t nRunning = 0,
nCount = wxGetApp().m_threads.Count();
for ( size_t n = 0; n < nCount; n++ )
{
if ( wxGetApp().m_threads[n]->IsRunning() )
nRunning++;
}
if ( nCount != m_nCount || nRunning != m_nRunning )
{
m_nRunning = nRunning;
m_nCount = nCount;
wxLogStatus(this, wxT("%u threads total, %u running."), unsigned(nCount), unsigned(nRunning));
}
//else: avoid flicker - don't print anything
}
void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event) )
{
Close(true);
}
void MyFrame::OnExecMain(wxCommandEvent& WXUNUSED(event))
{
wxLogMessage(wxT("The exit code from the main program is %ld"),
EXEC(_T("/bin/echo \"main program\"")));
}
void MyFrame::OnExecThread(wxCommandEvent& WXUNUSED(event))
{
MyExecThread thread(wxT("/bin/echo \"child thread\""));
thread.Run();
wxLogMessage(wxT("The exit code from a child thread is %ld"),
(long)wxPtrToUInt(thread.Wait()));
}
void MyFrame::OnShowCPUs(wxCommandEvent& WXUNUSED(event))
{
wxString msg;
int nCPUs = wxThread::GetCPUCount();
switch ( nCPUs )
{
case -1:
msg = _T("Unknown number of CPUs");
break;
case 0:
msg = _T("WARNING: you're running without any CPUs!");
break;
case 1:
msg = _T("This system only has one CPU.");
break;
default:
msg.Printf(wxT("This system has %d CPUs"), nCPUs);
}
wxLogMessage(msg);
}
void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event) )
{
wxMessageDialog dialog(this,
_T("wxWidgets multithreaded application sample\n")
_T("(c) 1998 Julian Smart, Guilhem Lavaux\n")
_T("(c) 1999 Vadim Zeitlin\n")
_T("(c) 2000 Robert Roebling"),
_T("About wxThread sample"),
wxOK | wxICON_INFORMATION);
dialog.ShowModal();
}
void MyFrame::OnClear(wxCommandEvent& WXUNUSED(event))
{
m_txtctrl->Clear();
}
void MyFrame::OnUpdateWorker(wxUpdateUIEvent& event)
{
event.Enable( m_dlgProgress == NULL );
}
void MyFrame::OnStartWorker(wxCommandEvent& WXUNUSED(event))
{
MyWorkerThread *thread = new MyWorkerThread(this);
if ( thread->Create() != wxTHREAD_NO_ERROR )
{
wxLogError(wxT("Can't create thread!"));
return;
}
m_dlgProgress = new wxProgressDialog
(
_T("Progress dialog"),
_T("Wait until the thread terminates or press [Cancel]"),
100,
this,
wxPD_CAN_ABORT |
wxPD_APP_MODAL |
wxPD_ELAPSED_TIME |
wxPD_ESTIMATED_TIME |
wxPD_REMAINING_TIME
);
// thread is not running yet, no need for crit sect
m_cancelled = false;
thread->Run();
}
void MyFrame::OnWorkerEvent(wxCommandEvent& event)
{
int n = event.GetInt();
if ( n == -1 )
{
m_dlgProgress->Destroy();
m_dlgProgress = (wxProgressDialog *)NULL;
// the dialog is aborted because the event came from another thread, so
// we may need to wake up the main event loop for the dialog to be
// really closed
wxWakeUpIdle();
}
else
{
if ( !m_dlgProgress->Update(n) )
{
wxCriticalSectionLocker lock(m_critsectWork);
m_cancelled = true;
}
}
}
bool MyFrame::Cancelled()
{
wxCriticalSectionLocker lock(m_critsectWork);
return m_cancelled;
}
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