The dialog sample illustrates this approach by defining a custom log target
customizing the dialog used by wxLogGui for the single messages.
+
+@section overview_log_mt Logging in Multi-Threaded Applications
+
+Starting with wxWidgets 2.9.1, logging functions can be safely called from any
+thread. Messages logged from threads other than the main one will be buffered
+until wxLog::Flush() is called in the main thread (which usually happens during
+idle time, i.e. after processing all pending events) and will be really output
+only then. Notice that the default GUI logger already only output the messages
+when it is flushed, so by default messages from the other threads will be shown
+more or less at the same moment as usual. However if you define a custom log
+target, messages may be logged out of order, e.g. messages from the main thread
+with later timestamp may appear before messages with earlier timestamp logged
+from other threads. wxLog does however guarantee that messages logged by each
+thread will appear in order in which they were logged.
+
*/
#define wxLOG_KEY_TRACE_MASK "wx.trace_mask"
+// ----------------------------------------------------------------------------
+// log record: a unit of log output
+// ----------------------------------------------------------------------------
+
+struct wxLogRecord
+{
+ wxLogRecord(wxLogLevel level_,
+ const wxString& msg_,
+ const wxLogRecordInfo& info_)
+ : level(level_),
+ msg(msg_),
+ info(info_)
+ {
+ }
+
+ wxLogLevel level;
+ wxString msg;
+ wxLogRecordInfo info;
+};
+
// ----------------------------------------------------------------------------
// derive from this class to redirect (or suppress, or ...) log messages
// normally, only a single instance of this class exists but it's not enforced
// caller had already locked GetPreviousLogCS()
unsigned LogLastRepeatIfNeededUnlocked();
+ // called from OnLog() if it's called from the main thread and from Flush()
+ // when it plays back the buffered messages logged from the other threads
+ void OnLogInMainThread(wxLogLevel level,
+ const wxString& msg,
+ const wxLogRecordInfo& info);
+
+
// static variables
// ----------------
/**
Shows all the messages currently in buffer and clears it.
+
If the buffer is already empty, nothing happens.
+
+ It should only be called from the main application thread.
+
+ If you override this method in a derived class, call the base class
+ version first, before doing anything else, to ensure that any buffered
+ messages from the other threads are logged.
*/
virtual void Flush();
/**
Flushes the current log target if any, does nothing if there is none.
- @see Flush()
+ As Flush() itself, this method should only be called from the main
+ application thread.
*/
static void FlushActive();
// the main application frame
// ----------------------------------------------------------------------------
-class MyFrame: public wxFrame
+class MyFrame : public wxFrame,
+ private wxLog
{
public:
// ctor
- MyFrame(wxFrame *frame, const wxString& title, int x, int y, int w, int h);
+ MyFrame(const wxString& title);
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();
+protected:
+ virtual void DoLogRecord(wxLogLevel level,
+ const wxString& msg,
+ const wxLogRecordInfo& info);
+
private:
// event handlers
// --------------
void OnUpdateWorker(wxUpdateUIEvent& event);
+ // logging helper
+ void DoLogLine(wxTextCtrl *text,
+ const wxString& timestr,
+ const wxString& threadstr,
+ const wxString& msg);
+
+
// thread helper functions
// -----------------------
// update display in our status bar: called during idle handling
void UpdateThreadStatus();
- // log the messages queued by LogThreadMessage()
- void DoLogThreadMessages();
-
// internal variables
// ------------------
// just some place to put our messages in
wxTextCtrl *m_txtctrl;
+ // old log target, we replace it with one using m_txtctrl during this
+ // frame life time
+ wxLog *m_oldLogger;
+
// the array of pending messages to be displayed and the critical section
// protecting it
wxArrayString m_messages;
class MyThread : public wxThread
{
public:
- MyThread(MyFrame *frame);
+ MyThread();
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;
};
// ----------------------------------------------------------------------------
wxLog::AddTraceMask("thread");
// Create the main frame window
- MyFrame *frame = new MyFrame((wxFrame *)NULL, _T("wxWidgets threads sample"),
- 50, 50, 450, 340);
- SetTopWindow(frame);
-
- // Show the frame
- frame->Show(true);
+ new MyFrame("wxWidgets threads sample");
return true;
}
END_EVENT_TABLE()
// 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))
+MyFrame::MyFrame(const wxString& title)
+ : wxFrame(NULL, wxID_ANY, title)
{
+ m_oldLogger = wxLog::GetActiveTarget();
+
SetIcon(wxIcon(sample_xpm));
// Make a menubar
m_nRunning = m_nCount = 0;
- m_dlgProgress = (wxProgressDialog *)NULL;
+ m_dlgProgress = NULL;
#if wxUSE_STATUSBAR
CreateStatusBar(2);
#endif // wxUSE_STATUSBAR
- m_txtctrl = new wxTextCtrl(this, wxID_ANY, _T(""), wxPoint(0, 0), wxSize(0, 0),
+ // create the logging text control and a header showing the meaning of the
+ // different columns
+ wxTextCtrl *header = new wxTextCtrl(this, wxID_ANY, "",
+ wxDefaultPosition, wxDefaultSize,
+ wxTE_READONLY);
+ DoLogLine(header, " Time", " Thread", "Message");
+ m_txtctrl = new wxTextCtrl(this, wxID_ANY, "",
+ wxDefaultPosition, wxDefaultSize,
wxTE_MULTILINE | wxTE_READONLY);
+ wxLog::SetActiveTarget(this);
+
+ // use fixed width font to align output in nice columns
+ wxFont font(wxNORMAL_FONT->GetPointSize(), wxFONTFAMILY_TELETYPE,
+ wxFONTSTYLE_NORMAL, wxFONTWEIGHT_NORMAL);
+ header->SetFont(font);
+ m_txtctrl->SetFont(font);
+
+ m_txtctrl->SetFocus();
+
+ // layout and show the frame
+ wxBoxSizer *sizer = new wxBoxSizer(wxVERTICAL);
+ sizer->Add(header, wxSizerFlags().Expand());
+ sizer->Add(m_txtctrl, wxSizerFlags(1).Expand());
+ SetSizer(sizer);
+
+ SetSize(600, 350);
+ Show();
}
MyFrame::~MyFrame()
{
+ wxLog::SetActiveTarget(m_oldLogger);
+
// 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
wxGetApp().m_semAllDone.Wait();
}
-MyThread *MyFrame::CreateThread()
+void
+MyFrame::DoLogLine(wxTextCtrl *text,
+ const wxString& timestr,
+ const wxString& threadstr,
+ const wxString& msg)
{
- MyThread *thread = new MyThread(this);
+ text->AppendText(wxString::Format("%9s %10s %s", timestr, threadstr, msg));
+}
- if ( thread->Create() != wxTHREAD_NO_ERROR )
+void
+MyFrame::DoLogRecord(wxLogLevel level,
+ const wxString& msg,
+ const wxLogRecordInfo& info)
+{
+ // let the default GUI logger treat warnings and errors as they should be
+ // more noticeable than just another line in the log window and also trace
+ // messages as there may be too many of them
+ if ( level <= wxLOG_Warning || level == wxLOG_Trace )
{
- wxLogError(wxT("Can't create thread!"));
+ m_oldLogger->LogRecord(level, msg, info);
+ return;
}
- wxCriticalSectionLocker enter(wxGetApp().m_critsect);
- wxGetApp().m_threads.Add(thread);
-
- return thread;
+ DoLogLine
+ (
+ m_txtctrl,
+ wxDateTime(info.timestamp).FormatISOTime(),
+ info.threadId == wxThread::GetMainId()
+ ? wxString("main")
+ : wxString::Format("%x", info.threadId),
+ msg + "\n"
+ );
}
-void MyFrame::DoLogThreadMessages()
+MyThread *MyFrame::CreateThread()
{
- wxCriticalSectionLocker lock(m_csMessages);
+ MyThread *thread = new MyThread;
- const size_t count = m_messages.size();
- for ( size_t n = 0; n < count; n++ )
+ if ( thread->Create() != wxTHREAD_NO_ERROR )
{
- m_txtctrl->AppendText(m_messages[n]);
+ wxLogError(wxT("Can't create thread!"));
}
- m_messages.clear();
+ wxCriticalSectionLocker enter(wxGetApp().m_critsect);
+ wxGetApp().m_threads.Add(thread);
+
+ return thread;
}
void MyFrame::UpdateThreadStatus()
void MyFrame::OnIdle(wxIdleEvent& event)
{
- DoLogThreadMessages();
-
UpdateThreadStatus();
event.Skip();
// MyThread
// ----------------------------------------------------------------------------
-MyThread::MyThread(MyFrame *frame)
+MyThread::MyThread()
: wxThread()
{
m_count = 0;
- m_frame = frame;
}
MyThread::~MyThread()
wxThread::ExitCode MyThread::Entry()
{
- wxString text;
-
- text.Printf(wxT("Thread %p started (priority = %u).\n"),
- GetId(), GetPriority());
- WriteText(text);
- // wxLogMessage(text); -- test wxLog thread safeness
+ wxLogMessage("Thread started (priority = %u).", GetPriority());
for ( m_count = 0; m_count < 10; m_count++ )
{
if ( TestDestroy() )
break;
- text.Printf(wxT("[%u] Thread %p here.\n"), m_count, GetId());
- WriteText(text);
+ wxLogMessage("Thread progress: %u", m_count);
// wxSleep() can't be called from non-GUI thread!
wxThread::Sleep(1000);
}
- text.Printf(wxT("Thread %p finished.\n"), GetId());
- WriteText(text);
- // wxLogMessage(text); -- test wxLog thread safeness
+ wxLogMessage("Thread finished.");
return NULL;
}
#include "wx/textfile.h"
#include "wx/thread.h"
#include "wx/crt.h"
+#include "wx/vector.h"
// other standard headers
#ifndef __WXWINCE__
#if wxUSE_THREADS
+namespace
+{
+
+// contains messages logged by the other threads and waiting to be shown until
+// Flush() is called in the main one
+typedef wxVector<wxLogRecord> wxLogRecords;
+wxLogRecords gs_bufferedLogRecords;
+
+
// define static functions providing access to the critical sections we use
// instead of just using static critical section variables as log functions may
// be used during static initialization and while this is certainly not
// advisable it's still better to not crash (as we'd do if we used a yet
// uninitialized critical section) if it happens
-static inline wxCriticalSection& GetTraceMaskCS()
+// this critical section is used for buffering the messages from threads other
+// than main, i.e. it protects all accesses to gs_bufferedLogRecords above
+inline wxCriticalSection& GetBackgroundLogCS()
+{
+ static wxCriticalSection s_csBackground;
+
+ return s_csBackground;
+}
+
+inline wxCriticalSection& GetTraceMaskCS()
{
static wxCriticalSection s_csTrace;
return s_csTrace;
}
-static inline wxCriticalSection& GetPreviousLogCS()
+inline wxCriticalSection& GetPreviousLogCS()
{
static wxCriticalSection s_csPrev;
return s_csPrev;
}
-static inline wxCriticalSection& GetLevelsCS()
+inline wxCriticalSection& GetLevelsCS()
{
static wxCriticalSection s_csLevels;
return s_csLevels;
}
+} // anonymous namespace
+
#endif // wxUSE_THREADS
// ----------------------------------------------------------------------------
if ( !pLogger )
return;
+#if wxUSE_THREADS
+ if ( !wxThread::IsMain() )
+ {
+ wxCriticalSectionLocker lock(GetBackgroundLogCS());
+
+ gs_bufferedLogRecords.push_back(wxLogRecord(level, msg, info));
+
+ // ensure that our Flush() will be called soon
+ wxWakeUpIdle();
+
+ return;
+ }
+#endif // wxUSE_THREADS
+
+ pLogger->OnLogInMainThread(level, msg, info);
+}
+
+void
+wxLog::OnLogInMainThread(wxLogLevel level,
+ const wxString& msg,
+ const wxLogRecordInfo& info)
+{
if ( GetRepetitionCounting() )
{
wxCRIT_SECT_LOCKER(lock, GetPreviousLogCS());
return;
}
- pLogger->LogLastRepeatIfNeededUnlocked();
+ LogLastRepeatIfNeededUnlocked();
// reset repetition counter for a new message
gs_prevLog.msg = msg;
}
#endif // wxUSE_LOG_TRACE
- pLogger->DoLogRecord(level, prefix + msg + suffix, info);
+ DoLogRecord(level, prefix + msg + suffix, info);
}
void wxLog::DoLogRecord(wxLogLevel level,
void wxLog::Flush()
{
+#if wxUSE_THREADS
+ wxASSERT_MSG( wxThread::IsMain(),
+ "should be called from the main thread only" );
+
+ // check if we have queued messages from other threads
+ wxLogRecords bufferedLogRecords;
+
+ {
+ wxCriticalSectionLocker lock(GetBackgroundLogCS());
+ bufferedLogRecords.swap(gs_bufferedLogRecords);
+
+ // release the lock now to not keep it while we are logging the
+ // messages below, allowing background threads to run
+ }
+
+ if ( !bufferedLogRecords.empty() )
+ {
+ for ( wxLogRecords::const_iterator it = bufferedLogRecords.begin();
+ it != bufferedLogRecords.end();
+ ++it )
+ {
+ OnLogInMainThread(it->level, it->msg, it->info);
+ }
+ }
+#endif // wxUSE_THREADS
+
LogLastRepeatIfNeeded();
}
void wxLogBuffer::Flush()
{
+ wxLog::Flush();
+
if ( !m_str.empty() )
{
wxMessageOutputBest out;
#include "wx/arrstr.h"
#include "wx/msgout.h"
-#if wxUSE_THREADS
- #include "wx/thread.h"
-#endif // wxUSE_THREADS
-
#ifdef __WXMSW__
// for OutputDebugString()
#include "wx/msw/private.h"
void wxLogGui::Flush()
{
+ wxLog::Flush();
+
if ( !m_bHasMessages )
return;
#endif // CAN_SAVE_FILES
void OnClear(wxCommandEvent& event);
- // this function is safe to call from any thread (notice that it should be
- // also called from the main thread to ensure that the messages logged from
- // it appear in correct order with the messages from the other threads)
- void AddLogMessage(const wxString& message);
-
- // actually append the messages logged from secondary threads to the text
- // control during idle time in the main thread
- virtual void OnInternalIdle();
+ // do show the message in the text control
+ void ShowLogMessage(const wxString& message)
+ {
+ m_pTextCtrl->AppendText(message + wxS('\n'));
+ }
private:
// use standard ids for our commands!
// common part of OnClose() and OnCloseWindow()
void DoClose();
- // do show the message in the text control
- void DoShowLogMessage(const wxString& message)
- {
- m_pTextCtrl->AppendText(message + wxS('\n'));
- }
-
wxTextCtrl *m_pTextCtrl;
wxLogWindow *m_log;
- // queue of messages logged from other threads which need to be displayed
- wxArrayString m_pendingMessages;
-
-#if wxUSE_THREADS
- // critical section to protect access to m_pendingMessages
- wxCriticalSection m_critSection;
-#endif // wxUSE_THREADS
-
-
DECLARE_EVENT_TABLE()
wxDECLARE_NO_COPY_CLASS(wxLogFrame);
};
m_pTextCtrl->Clear();
}
-void wxLogFrame::OnInternalIdle()
-{
- {
- wxCRIT_SECT_LOCKER(locker, m_critSection);
-
- const size_t count = m_pendingMessages.size();
- for ( size_t n = 0; n < count; n++ )
- {
- DoShowLogMessage(m_pendingMessages[n]);
- }
-
- m_pendingMessages.clear();
- } // release m_critSection
-
- wxFrame::OnInternalIdle();
-}
-
-void wxLogFrame::AddLogMessage(const wxString& message)
-{
- wxCRIT_SECT_LOCKER(locker, m_critSection);
-
-#if wxUSE_THREADS
- if ( !wxThread::IsMain() || !m_pendingMessages.empty() )
- {
- // message needs to be queued for later showing
- m_pendingMessages.Add(message);
-
- wxWakeUpIdle();
- }
- else // we are the main thread and no messages are queued, so we can
- // log the message directly
-#endif // wxUSE_THREADS
- {
- DoShowLogMessage(message);
- }
-}
-
wxLogFrame::~wxLogFrame()
{
m_log->OnFrameDelete(this);
if ( level == wxLOG_Trace )
return;
- m_pLogFrame->AddLogMessage(msg);
+ m_pLogFrame->ShowLogMessage(msg);
}
wxFrame *wxLogWindow::GetFrame() const
projects / wxWidgets.git / commitdiff
