private ViewCache applyUserOverwrite()

in src/main/java/com/google/firebase/database/core/view/ViewProcessor.java [354:421]
63 lines of code
8 McCabe index (conditional complexity)

  private ViewCache applyUserOverwrite(
      ViewCache oldViewCache,
      Path changePath,
      Node changedSnap,
      WriteTreeRef writesCache,
      Node optCompleteCache,
      ChildChangeAccumulator accumulator) {
    CacheNode oldEventSnap = oldViewCache.getEventCache();
    ViewCache newViewCache;
    NodeFilter.CompleteChildSource source =
        new WriteTreeCompleteChildSource(writesCache, oldViewCache, optCompleteCache);
    if (changePath.isEmpty()) {
      IndexedNode newIndexed = IndexedNode.from(changedSnap, this.filter.getIndex());
      IndexedNode newEventCache =
          this.filter.updateFullNode(
              oldViewCache.getEventCache().getIndexedNode(), newIndexed, accumulator);
      newViewCache = oldViewCache.updateEventSnap(newEventCache, true, this.filter.filtersNodes());
    } else {
      ChildKey childKey = changePath.getFront();
      if (childKey.isPriorityChildName()) {
        IndexedNode newEventCache =
            this.filter.updatePriority(oldViewCache.getEventCache().getIndexedNode(), changedSnap);
        newViewCache =
            oldViewCache.updateEventSnap(
                newEventCache, oldEventSnap.isFullyInitialized(), oldEventSnap.isFiltered());
      } else {
        Path childChangePath = changePath.popFront();
        Node oldChild = oldEventSnap.getNode().getImmediateChild(childKey);
        Node newChild;
        if (childChangePath.isEmpty()) {
          // Child overwrite, we can replace the child
          newChild = changedSnap;
        } else {
          Node childNode = source.getCompleteChild(childKey);
          if (childNode != null) {
            if (childChangePath.getBack().isPriorityChildName()
                && childNode.getChild(childChangePath.getParent()).isEmpty()) {
              // This is a priority update on an empty node. If this node exists on
              // the server, the
              // server will send down the priority in the update, so ignore for now
              newChild = childNode;
            } else {
              newChild = childNode.updateChild(childChangePath, changedSnap);
            }
          } else {
            // There is no complete child node available
            newChild = EmptyNode.Empty();
          }
        }
        if (!oldChild.equals(newChild)) {
          IndexedNode newEventSnap =
              this.filter.updateChild(
                  oldEventSnap.getIndexedNode(),
                  childKey,
                  newChild,
                  childChangePath,
                  source,
                  accumulator);
          newViewCache =
              oldViewCache.updateEventSnap(
                  newEventSnap, oldEventSnap.isFullyInitialized(), this.filter.filtersNodes());
        } else {
          newViewCache = oldViewCache;
        }
      }
    }
    return newViewCache;
  }