Made wxLogXXX() functions thread-safe.

They can now be called from any thread and will buffer the messages until the
current log target is flushed from the main thread. This makes earlier code to
do the same thing specifically for wxLogWindow unnecessary and also allows to
use wxLogMessage() in the thread sample instead of using manual logging there.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61416 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/log.cpp

@@ -43,6 +43,7 @@
 #include "wx/textfile.h"
 #include "wx/thread.h"
 #include "wx/crt.h"
+#include "wx/vector.h"
 
 // other standard headers
 #ifndef __WXWINCE__
@@ -68,33 +69,53 @@ const char *wxLOG_COMPONENT = "";
 
 #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
 
 // ----------------------------------------------------------------------------
@@ -256,6 +277,28 @@ wxLog::OnLog(wxLogLevel level,
     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());
@@ -269,7 +312,7 @@ wxLog::OnLog(wxLogLevel level,
             return;
         }
 
-        pLogger->LogLastRepeatIfNeededUnlocked();
+        LogLastRepeatIfNeededUnlocked();
 
         // reset repetition counter for a new message
         gs_prevLog.msg = msg;
@@ -297,7 +340,7 @@ wxLog::OnLog(wxLogLevel level,
     }
 #endif // wxUSE_LOG_TRACE
 
-    pLogger->DoLogRecord(level, prefix + msg + suffix, info);
+    DoLogRecord(level, prefix + msg + suffix, info);
 }
 
 void wxLog::DoLogRecord(wxLogLevel level,
@@ -557,6 +600,32 @@ void wxLog::TimeStamp(wxString *str)
 
 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();
 }
 
@@ -566,6 +635,8 @@ void wxLog::Flush()
 
 void wxLogBuffer::Flush()
 {
+    wxLog::Flush();
+
     if ( !m_str.empty() )
     {
         wxMessageOutputBest out;