1 files changed, 24 insertions, 4 deletions

diff --git a/libkcal/incidence.cpp b/libkcal/incidence.cpp
index 11f7ecc..e4bcc5e 100644
--- a/libkcal/incidence.cpp
+++ b/libkcal/incidence.cpp
@@ -282,5 +282,25 @@ void Incidence::setReadOnly( bool readOnly )
   recurrence()->setRecurReadOnly( readOnly);
 }
-
+void Incidence::setLastModifiedSubInvalid()
+{
+    mLastModifiedSub = QDateTime();
+    if ( mRelatedTo )
+        mRelatedTo->setLastModifiedSubInvalid();
+}
+QDateTime Incidence::lastModifiedSub()
+{
+    if ( !mRelations.count() )
+        return lastModified();
+    if ( mLastModifiedSub.isValid() )
+        return mLastModifiedSub;
+    mLastModifiedSub = lastModified();
+    Incidence * inc;
+    QPtrList<Incidence> Relations = relations();
+    for (inc=Relations.first();inc;inc=Relations.next()) {
+        if ( inc->lastModifiedSub() > mLastModifiedSub )
+            mLastModifiedSub = inc->lastModifiedSub();
+    }
+    return mLastModifiedSub;
+}
 void Incidence::setCreated(QDateTime created)
 {
@@ -469,4 +489,5 @@ void Incidence::addRelationsToList(QPtrList<Incidence> *rel)
 void Incidence::addRelation(Incidence *event)
 {
+    setLastModifiedSubInvalid();
   if( mRelations.findRef( event ) == -1 ) {
     mRelations.append(event);
@@ -477,7 +498,6 @@ void Incidence::addRelation(Incidence *event)
 void Incidence::removeRelation(Incidence *event)
 {
-  
-  mRelations.removeRef(event); 
- 
+    setLastModifiedSubInvalid();
+  mRelations.removeRef(event);
 //  if (event->getRelatedTo() == this) event->setRelatedTo(0);
 }