cache: use disk states to share caches

app/render/playbackcache.cpp

@@ -39,6 +39,8 @@ void PlaybackCache::Invalidate(const TimeRange &r)
   InvalidateEvent(r);
 
   emit Invalidated(r);
+
+  SaveState();
 }
 
 Node *PlaybackCache::parent() const
@@ -89,8 +91,6 @@ void PlaybackCache::LoadState()
     }
 
     f.close();
-
-    f.close();
   }
 }
 
@@ -165,6 +165,8 @@ void PlaybackCache::Validate(const TimeRange &r, bool signal)
   if (signal) {
     emit Validated(r);
   }
+
+  SaveState();
 }
 
 void PlaybackCache::InvalidateEvent(const TimeRange &)
@@ -182,6 +184,13 @@ PlaybackCache::PlaybackCache(QObject *parent) :
   uuid_ = QUuid::createUuid();
 }
 
+void PlaybackCache::SetUuid(const QUuid &u)
+{
+  uuid_ = u;
+
+  LoadState();
+}
+
 TimeRangeList PlaybackCache::GetInvalidatedRanges(TimeRange intersecting) const
 {
   TimeRangeList invalidated;