use signals for logging

python/core/qgsmessagelog.sip

@@ -3,8 +3,15 @@ class QgsMessageLog
 %TypeHeaderCode
 #include <qgsmessagelog.h>
 %End
-
   public:
+    static QgsMessageLog *instance();
+
     //! add a message to the instance (and create it if necessary)
     static void logMessage( QString message, QString tag = QString::null, int level = 0 );
+
+  signals:
+    void messageReceived( QString message, QString tag, int level );
+
+  private:
+    QgsMessageLog();
 };

src/core/CMakeLists.txt

@@ -240,6 +240,7 @@ SET(QGIS_CORE_MOC_HDRS
   qgsmaplayerregistry.h
   qgsmaprenderer.h
   qgsmessageoutput.h
+  qgsmessagelog.h
   qgscredentials.h
   qgspluginlayer.h
   qgsproject.h

src/core/qgsmessagelog.cpp

@@ -20,24 +20,42 @@
 
 class QgsMessageLogConsole;
 
-void ( *QgsMessageLog::gmLogger )( QString message, QString tag, int level ) = 0;
+QgsMessageLog *QgsMessageLog::sInstance = 0;
 
-void QgsMessageLog::setLogger( void ( *f )( QString message, QString tag, int level ) )
+QgsMessageLog::QgsMessageLog()
+    : QObject()
 {
-  gmLogger = f;
+  sInstance = this;
+}
+
+QgsMessageLog *QgsMessageLog::instance()
+{
+  if ( !sInstance )
+    sInstance = new QgsMessageLog();
+
+  return sInstance;
 }
 
 void QgsMessageLog::logMessage( QString message, QString tag, int level )
 {
   QgsDebugMsg( QString( "%1 %2[%3] %4" ).arg( QDateTime::currentDateTime().toString( Qt::ISODate ) ).arg( tag ).arg( level ).arg( message ) );
 
-  if ( !gmLogger )
-    QgsMessageLogConsole::logger( message, tag, level );
-  else
-    gmLogger( message, tag, level );
+  QgsMessageLog::instance()->emitMessage( message, tag, level );
 }
 
-void QgsMessageLogConsole::logger( QString message, QString tag, int level )
+void QgsMessageLog::emitMessage( QString message, QString tag, int level )
+{
+  emit messageReceived( message, tag, level );
+}
+
+QgsMessageLogConsole::QgsMessageLogConsole()
+    : QObject( QgsMessageLog::instance() )
+{
+  connect( QgsMessageLog::instance(), SIGNAL( messageReceived( QString, QString, int ) ),
+           this, SLOT( logMessage( QString, QString, tag ) ) );
+}
+
+void QgsMessageLogConsole::logMessage( QString message, QString tag, int level )
 {
   std::cout << tag.toLocal8Bit().data() << "[" << level << "]: " << message.toLocal8Bit().data() << std::endl;
 }

src/core/qgsmessagelog.h

@@ -30,18 +30,25 @@
 
  * \note added in 1.9
 */
-class CORE_EXPORT QgsMessageLog
+class CORE_EXPORT QgsMessageLog : public QObject
 {
+    Q_OBJECT;
+
   public:
+    static QgsMessageLog *instance();
+
     //! add a message to the instance (and create it if necessary)
     static void logMessage( QString message, QString tag = QString::null, int level = 0 );
 
-    //! set log message
-    static void setLogger( void ( *logger )( QString message, QString tag, int level ) );
+  signals:
+    void messageReceived( QString message, QString tag, int level );
 
   private:
-    //! function
-    static void ( *gmLogger )( QString message, QString tag, int level );
+    QgsMessageLog();
+
+    void emitMessage( QString message, QString tag, int level );
+
+    static QgsMessageLog *sInstance;
 };
 
 
@@ -51,10 +58,15 @@ class CORE_EXPORT QgsMessageLog
 This class outputs log messages to the standard output. Therefore it might
 be the right choice for apps without GUI.
 */
-class CORE_EXPORT QgsMessageLogConsole
+class CORE_EXPORT QgsMessageLogConsole : public QObject
 {
+    Q_OBJECT;
+
   public:
-    static void logger( QString message, QString tag = QString::null, int level = 0 );
+    QgsMessageLogConsole();
+
+  public slots:
+    void logMessage( QString message, QString tag, int level );
 };
 
 #endif

src/gui/qgsmessagelogviewer.cpp

@@ -27,8 +27,6 @@
 #include <QToolTip>
 #include <QDockWidget>
 
-static QgsMessageLogViewer *gmInstance = 0;
-
 static QIcon icon( QString icon )
 {
   // try active theme
@@ -47,8 +45,9 @@ QgsMessageLogViewer::QgsMessageLogViewer( QStatusBar *statusBar, QWidget *parent
     , mCount( 0 )
 {
   setupUi( this );
-  gmInstance = this;
-  QgsMessageLog::setLogger( logger );
+
+  connect( QgsMessageLog::instance(), SIGNAL( messageReceived( QString, QString, int ) ),
+           this, SLOT( logMessage( QString, QString, int ) ) );
 
   if ( statusBar )
   {
@@ -68,7 +67,6 @@ QgsMessageLogViewer::QgsMessageLogViewer( QStatusBar *statusBar, QWidget *parent
 
 QgsMessageLogViewer::~QgsMessageLogViewer()
 {
-  QgsMessageLog::setLogger( 0 );
 }
 
 void QgsMessageLogViewer::hideEvent( QHideEvent * )
@@ -100,14 +98,6 @@ void QgsMessageLogViewer::buttonToggled( bool checked )
     w->hide();
 }
 
-void QgsMessageLogViewer::logger( QString message, QString tag, int level )
-{
-  if ( !gmInstance )
-    return;
-
-  gmInstance->logMessage( message, tag, level );
-}
-
 void QgsMessageLogViewer::logMessage( QString message, QString tag, int level )
 {
   mButton->setToolTip( tr( "%1 message(s) logged." ).arg( mCount++ ) );

src/gui/qgsmessagelogviewer.h

@@ -32,16 +32,15 @@ class QHideEvent;
  * A generic message for displaying QGIS log messages.
  * \note added in 1.8
  */
-class GUI_EXPORT QgsMessageLogViewer: public QDialog, public QgsMessageLog, private Ui::QgsMessageLogViewer
+class GUI_EXPORT QgsMessageLogViewer: public QDialog, private Ui::QgsMessageLogViewer
 {
     Q_OBJECT
   public:
     QgsMessageLogViewer( QStatusBar *statusBar = 0, QWidget *parent = 0, Qt::WFlags fl = QgisGui::ModalDialogFlags );
     ~QgsMessageLogViewer();
 
-    void logMessage( QString message, QString tag = QString::null, int level = 0 );
-
-    static void logger( QString message, QString tag, int level );
+  public slots:
+    void logMessage( QString message, QString tag, int level );
 
   private:
     void showEvent( QShowEvent * );