Cache the result of XQueryTree().

svn path=/trunk/KDE/kdebase/workspace/; revision=851667

composite.cpp

@@ -322,7 +322,7 @@ void Workspace::performCompositing()
         return;
         }
     // create a list of all windows in the stacking order
-    ToplevelList windows = compositingStackingOrder();
+    ToplevelList windows = xStackingOrder();
     foreach( EffectWindow* c, static_cast< EffectsHandlerImpl* >( effects )->elevatedWindows())
         {
         Toplevel* t = static_cast< EffectWindowImpl* >( c )->window();

events.cpp

@@ -279,6 +279,10 @@ bool Workspace::workspaceEvent( XEvent * e )
                 return true;
                 }
             break;
+        case ConfigureNotify:
+            if( e->xconfigure.event == rootWindow())
+                x_stacking_dirty = true;
+            break;
         };
 
     if( Client* c = findClient( WindowMatchPredicate( e->xany.window )))

layers.cpp

@@ -723,30 +723,32 @@ bool Workspace::keepTransientAbove( const Client* mainwindow, const Client* tran
     return true;
     }
 
-// Returns all windows in their stacking order on the root window, used only by compositing.
-// TODO This possibly should be optimized to avoid the X roundtrip and building it every pass.
-ToplevelList Workspace::compositingStackingOrder() const
+// Returns all windows in their stacking order on the root window.
+ToplevelList Workspace::xStackingOrder() const
     {
+    if( !x_stacking_dirty )
+        return x_stacking;
+    x_stacking_dirty = false;
+    x_stacking.clear();
     Window dummy;
     Window* windows = NULL;
     unsigned int count = 0;
     XQueryTree( display(), rootWindow(), &dummy, &dummy, &windows, &count );
-    ToplevelList ret;
     // use our own stacking order, not the X one, as they may differ
     foreach( Client* c, stacking_order )
-        ret.append( c );
+        x_stacking.append( c );
     for( unsigned int i = 0;
          i < count;
          ++i )
         {
         if( Unmanaged* c = findUnmanaged( WindowMatchPredicate( windows[ i ] )))
-            ret.append( c );
+            x_stacking.append( c );
         }
     foreach( Deleted* c, deleted )
-        ret.append( c );
+        x_stacking.append( c );
     if( windows != NULL )
         XFree( windows );
-    return ret;
+    return x_stacking;
     }
 
 //*******************************

workspace.cpp

@@ -99,6 +99,7 @@ Workspace::Workspace( bool restore )
     active_screen     (0),
     delayfocus_client (0),
     force_restacking( false ),
+    x_stacking_dirty( true ),
     showing_desktop( false ),
     block_showing_desktop( 0 ),
     was_user_interaction (false),
@@ -544,6 +545,7 @@ void Workspace::addClient( Client* c, allowed_t )
         stacking_order.append( c );    // c to be in stacking_order
     if( c->isTopMenu())
         addTopMenu( c );
+    x_stacking_dirty = true;
     updateClientArea(); // this cannot be in manage(), because the client got added only now
     updateClientLayer( c );
     if( c->isDesktop())
@@ -566,6 +568,7 @@ void Workspace::addClient( Client* c, allowed_t )
 void Workspace::addUnmanaged( Unmanaged* c, allowed_t )
     {
     unmanaged.append( c );
+    x_stacking_dirty = true;
     }
 
 /*
@@ -597,6 +600,7 @@ void Workspace::removeClient( Client* c, allowed_t )
     desktops.removeAll( c );
     unconstrained_stacking_order.removeAll( c );
     stacking_order.removeAll( c );
+    x_stacking_dirty = true;
     for( int i = 1;
          i <= numberOfDesktops();
          ++i )
@@ -633,12 +637,14 @@ void Workspace::removeUnmanaged( Unmanaged* c, allowed_t )
     {
     assert( unmanaged.contains( c ));
     unmanaged.removeAll( c );
+    x_stacking_dirty = true;
     }
 
 void Workspace::addDeleted( Deleted* c, allowed_t )
     {
     assert( !deleted.contains( c ));
     deleted.append( c );
+    x_stacking_dirty = true;
     }
 
 void Workspace::removeDeleted( Deleted* c, allowed_t )
@@ -649,6 +655,7 @@ void Workspace::removeDeleted( Deleted* c, allowed_t )
     if( effects )
         static_cast<EffectsHandlerImpl*>(effects)->windowDeleted( c->effectWindow());
     deleted.removeAll( c );
+    x_stacking_dirty = true;
     }
 
 void Workspace::updateFocusChains( Client* c, FocusChainChange change )

workspace.h

@@ -518,7 +518,7 @@ class Workspace : public QObject, public KDecorationDefines
         bool establishTabBoxGrab();
         void removeTabBoxGrab();
 
-        ToplevelList compositingStackingOrder() const;
+        ToplevelList xStackingOrder() const;
         void propagateClients( bool propagate_new_clients ); // called only from updateStackingOrder
         ClientList constrainedStackingOrder();
         void raiseClientWithinApplication( Client* c );
@@ -613,6 +613,8 @@ class Workspace : public QObject, public KDecorationDefines
         ClientList unconstrained_stacking_order; // topmost last
         ClientList stacking_order; // topmost last
         bool force_restacking;
+        mutable ToplevelList x_stacking; // from XQueryTree()
+        mutable bool x_stacking_dirty;
         QVector< ClientList > focus_chain; // currently ative last
         ClientList global_focus_chain; // this one is only for things like tabbox's MRU
         ClientList should_get_focus; // last is most recent