Make sure there aren't two windows given focus with the same X timestamp,

because if one timestamp is reused for activating window A and then
immediatelly window B, and A will want to set focus to one
of its subwindows after receiving WM_TAKE_FOCUS, and will lag a bit,
it will actually set the focus after B, and will win. Fixes #71704.

If somebody still gets the warning, I'd be interested in the backtrace.

svn path=/trunk/kdebase/kwin/; revision=278208

activation.cpp

@@ -266,7 +266,9 @@ void Workspace::activateClient( Client* c, bool force )
     raiseClient( c );
     if (!c->isOnDesktop(currentDesktop()) )
         {
+        ++block_focus;
         setCurrentDesktop( c->desktop() );
+        --block_focus;
         // popupinfo->showInfo( desktopName(currentDesktop()) ); // AK - not sure
         }
     if( c->isMinimized())
@@ -339,8 +341,6 @@ void Workspace::requestFocus( Client* c, bool force )
 
   \a c may already be destroyed
  */
-extern bool block_focus; // SELI
-
 void Workspace::clientHidden( Client* c )
     {
     assert( !c->isShown( true ) || !c->isOnCurrentDesktop());
@@ -353,7 +353,7 @@ void Workspace::clientHidden( Client* c )
     if( c == active_client )
         setActiveClient( NULL, Allowed );
     should_get_focus.remove( c );
-    if( !block_focus )
+    if( focusChangeEnabled())
         {
         if ( c->wantsTabFocus() && focus_chain.contains( c ) )
             {

client.cpp

@@ -1098,6 +1098,15 @@ void Client::takeFocus( bool force, allowed_t )
     if ( !force && ( isTopMenu() || isDock() || isSplash()) )
         return; // toplevel menus and dock windows don't take focus if not forced
 
+#ifndef NDEBUG
+    static Time previous_focus_timestamp;
+    if( previous_focus_timestamp == qt_x_time )
+        {
+        kdWarning( 1212 ) << "Repeated use of the same X timestamp for focus" << endl;
+        kdDebug( 1212 ) << kdBacktrace() << endl;
+        }
+    previous_focus_timestamp = qt_x_time;
+#endif
     if ( input ) 
         {
         XSetInputFocus( qt_xdisplay(), window(), RevertToPointerRoot, qt_x_time );

geometry.cpp

@@ -302,9 +302,9 @@ void Workspace::setClientIsMoving( Client *c )
     // window while still moving the first one.
     movingClient = c;
     if (movingClient)
-        setFocusChangeEnabled( false );
+        ++block_focus;
     else
-        setFocusChangeEnabled( true );
+        --block_focus;
     }
 
 /*!

workspace.cpp

@@ -49,8 +49,6 @@ namespace KWinInternal
 
 extern int screen_number;
 
-bool block_focus = FALSE;
-
 static Window null_focus_window = 0;
 
 Workspace *Workspace::_self = 0;
@@ -78,7 +76,7 @@ Workspace::Workspace( bool restore )
     control_grab      (false),
     tab_grab          (false),
     mouse_emulation   (false),
-    focus_change      (true),
+    block_focus       (0),
     tab_box           (0),
     popupinfo         (0),
     popup             (0),
@@ -289,6 +287,8 @@ void Workspace::init()
     active_client = NULL;
     rootInfo->setActiveWindow( None );
     focusToNull();
+    if( !kapp->isSessionRestored())
+        ++block_focus; // because it will be set below
 
     char nm[ 100 ];
     sprintf( nm, "_KDE_TOPMENU_OWNER_S%d", DefaultScreen( qt_xdisplay()));
@@ -352,7 +352,10 @@ void Workspace::init()
 
     Client* new_active_client = NULL;
     if( !kapp->isSessionRestored())
+        {
+        --block_focus;
         new_active_client = findClient( WindowMatchPredicate( client_info.activeWindow()));
+        }
     if( new_active_client == NULL
         && activeClient() == NULL && should_get_focus.count() == 0 ) // no client activated in manage()
         {
@@ -946,7 +949,7 @@ bool Workspace::setCurrentDesktop( int new_desktop )
 
     if( popup )
         popup->close();
-    block_focus = TRUE;
+    ++block_focus;
 // TODO    Q_ASSERT( block_stacking_updates == 0 ); // make sure stacking_order is up to date
     StackingUpdatesBlocker blocker( this );
 
@@ -982,7 +985,7 @@ bool Workspace::setCurrentDesktop( int new_desktop )
         }
 
     // restore the focus on this desktop
-    block_focus = FALSE;
+    --block_focus;
     Client* c = 0;
 
     if ( options->focusPolicyIsReasonable()) 

workspace.h

@@ -117,12 +117,10 @@ class Workspace : public QObject, public KWinInterface, public KDecorationDefine
         void gotFocusIn( const Client* );
         bool fakeRequestedActivity( Client* c );
         void unfakeActivity( Client* c );
+        bool focusChangeEnabled() { return block_focus == 0; }
 
         void updateColormap();
 
-        void setFocusChangeEnabled(bool b) { focus_change = b; }
-        bool focusChangeEnabled() { return focus_change; }
-
         /**
          * Indicates that the client c is being moved around by the user.
          */
@@ -445,7 +443,7 @@ class Workspace : public QObject, public KWinInterface, public KDecorationDefine
         bool mouse_emulation;
         unsigned int mouse_emulation_state;
         WId mouse_emulation_window;
-        bool focus_change;
+        int block_focus;
 
         TabBox* tab_box;
         PopupInfo* popupinfo;