Allow TQApplication objects to be constructed without a session manager

This relates to Bug 760
(cherry picked from commit 49075fd69d)

src/kernel/qapplication.cpp

@@ -730,10 +730,9 @@ void QApplication::process_cmdline( int* argcptr, char ** argv )
 //######### BINARY COMPATIBILITY constructor
 QApplication::QApplication( int &argc, char **argv )
 {
-    construct( argc, argv, GuiClient );
+    construct( argc, argv, GuiClient, true );
 }
 
-
 /*!
   Constructs an application object with \a argc command line arguments
   in \a argv. If \a GUIenabled is TRUE, a GUI application is
@@ -775,7 +774,55 @@ QApplication::QApplication( int &argc, char **argv )
 
 QApplication::QApplication( int &argc, char **argv, bool GUIenabled  )
 {
-    construct( argc, argv, GUIenabled ? GuiClient : Tty );
+    construct( argc, argv, GUIenabled ? GuiClient : Tty, true );
+}
+
+/*!
+  Constructs an application object with \a argc command line arguments
+  in \a argv. If \a GUIenabled is TRUE, a GUI application is
+  constructed, otherwise a non-GUI (console) application is created.
+  If \a SMEnabled is TRUE, session management support is enabled (default).
+
+  Set \a GUIenabled to FALSE for programs without a graphical user
+  interface that should be able to run without a window system.
+
+  Set \a SMEnabled to FALSE to disable session management.
+  Session management cannot be enabled at a later time if disabled here.
+
+  On X11, the window system is initialized if \a GUIenabled is TRUE.
+  If \a GUIenabled is FALSE, the application does not connect to the
+  X-server.
+  On Windows and Macintosh, currently the window system is always
+  initialized, regardless of the value of GUIenabled. This may change in
+  future versions of Qt.
+
+  The following example shows how to create an application that
+  uses a graphical interface when available.
+  \code
+  int main( int argc, char **argv )
+  {
+#ifdef Q_WS_X11
+    bool useGUI = getenv( "DISPLAY" ) != 0;
+#else
+    bool useGUI = TRUE;
+#endif
+    QApplication app(argc, argv, useGUI);
+
+    if ( useGUI ) {
+       //start GUI version
+       ...
+    } else {
+       //start non-GUI version
+       ...
+    }
+    return app.exec();
+  }
+\endcode
+*/
+
+QApplication::QApplication( int &argc, char **argv, bool GUIenabled, bool SMenabled  )
+{
+    construct( argc, argv, GUIenabled ? GuiClient : Tty, SMenabled );
 }
 
 /*!
@@ -788,7 +835,7 @@ QApplication::QApplication( int &argc, char **argv, bool GUIenabled  )
 */
 QApplication::QApplication( int &argc, char **argv, Type type )
 {
-    construct( argc, argv, type );
+    construct( argc, argv, type, true );
 }
 
 Q_EXPORT void qt_ucm_initialize( QApplication *theApp )
@@ -797,12 +844,12 @@ Q_EXPORT void qt_ucm_initialize( QApplication *theApp )
 	return;
     int argc = theApp->argc();
     char **argv = theApp->argv();
-    theApp->construct( argc, argv, qApp->type() );
+    theApp->construct( argc, argv, qApp->type(), true );
 
     Q_ASSERT( qApp == theApp );
 }
 
-void QApplication::construct( int &argc, char **argv, Type type )
+void QApplication::construct( int &argc, char **argv, Type type, bool enable_sm )
 {
     qt_appType = type;
     qt_is_gui_used = (type != Tty);
@@ -817,7 +864,7 @@ void QApplication::construct( int &argc, char **argv, Type type )
 
     qt_init( &argc, argv, type );   // Must be called before initialize()
     process_cmdline( &argc, argv );
-    initialize( argc, argv );
+    initialize( argc, argv, enable_sm );
     if ( qt_is_gui_used )
 	qt_maxWindowRect = desktop()->rect();
     if ( eventloop )
@@ -944,7 +991,7 @@ void QApplication::init_precmdline()
   Initializes the QApplication object, called from the constructors.
 */
 
-void QApplication::initialize( int argc, char **argv )
+void QApplication::initialize( int argc, char **argv, bool enable_sm )
 {
 #ifdef QT_THREAD_SUPPORT
     qt_mutex = new QMutex( TRUE );
@@ -963,10 +1010,12 @@ void QApplication::initialize( int argc, char **argv )
     is_app_running = TRUE; // no longer starting up
 
 #ifndef QT_NO_SESSIONMANAGER
-    // connect to the session manager
-    if ( !session_key )
-	session_key = new QString;
-    session_manager = new QSessionManager( qApp, session_id, *session_key );
+    if (enable_sm) {
+	// connect to the session manager
+	if ( !session_key )
+	    session_key = new QString;
+	session_manager = new QSessionManager( qApp, session_id, *session_key );
+    }
 #endif
 
 }

src/kernel/qapplication.h

@@ -76,6 +76,7 @@ class Q_EXPORT QApplication : public QObject
 public:
     QApplication( int &argc, char **argv );
     QApplication( int &argc, char **argv, bool GUIenabled );
+    QApplication( int &argc, char **argv, bool GUIenabled, bool SMenabled );
     enum Type { Tty, GuiClient, GuiServer };
     QApplication( int &argc, char **argv, Type );
 #if defined(Q_WS_X11)
@@ -320,8 +321,8 @@ protected:
     bool event(QEvent *);
 
 private:
-    void construct( int &argc, char **argv, Type );
-    void initialize( int, char ** );
+    void construct( int &argc, char **argv, Type, bool enable_sm );
+    void initialize( int, char **, bool enable_sm = true );
     void init_precmdline();
     void process_cmdline( int* argcptr, char ** argv );
     bool internalNotify( QObject *, QEvent * );