.

wcfs/δbtail.go

@@ -598,11 +598,14 @@ func (prs *rangeSplit) Expand(rnode *nodeInRange) (children rangeSplit) {
 	return children
 }
 
-// GetToBucket returns bucket corresponding to key k.
-// While reaching to that bucket, it expands step-by-step trees that are leading to that bucket.
+// GetToLeaf returns leaf node corresponding to key k.
+//
+// Leaf is usually bucket node, but, in the sole single case of empty tree, can be that root tree node.
+// GetToLeaf expands step-by-step every tree from where it has to traverse to next depth level.
+//
 // XXX also return path?
-func (prs *rangeSplit) GetToBucket(ctx context.Context, k Key) (rbucket *nodeInRange, ok bool, err error) {
-	rnode, ok := prs.Get_(k)
+func (prs *rangeSplit) GetToLeaf(ctx context.Context, k Key) (rnode *nodeInRange, ok bool, err error) {
+	rnode, ok = prs.Get_(k)
 	if !ok {
 		return nil, false, nil // key not covered
 	}
@@ -620,6 +623,8 @@ func (prs *rangeSplit) GetToBucket(ctx context.Context, k Key) (rbucket *nodeInR
 		}
 		defer rnode.node.PDeactivate()
 
+		// FIXME ø tree -> don't expand -> tree
+
 		children := prs.Expand(rnode)
 		rnode = children.Get(k) // k must be there
 	}
@@ -872,7 +877,7 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 		Aqueue = SetKey{}
 		for k := range Bqueue {
 			Bdone.Add(k)
-			bbucket, ok, err := bv.GetToBucket(ctx, k)
+			bnode, ok, err := bv.GetToLeaf(ctx, k)
 			if err != nil {
 				return nil, err
 			}
@@ -881,10 +886,12 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 				continue // key not covered
 			}
 
+			// XXX check for bnode.node.(*Tree)   (ø tree case)
+
 			// + bucket if not already done
 			// XXX update track.hole if k not in bbucket
-			if !bbucket.done {
-				δB, err := diffB(ctx, nil, bbucket.node.(*Bucket))
+			if !bnode.done {
+				δB, err := diffB(ctx, nil, bnode.node.(*Bucket))
 				if err != nil {
 					return nil, err
 				}
@@ -902,7 +909,7 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 					}
 				}
 
-				bbucket.done = true
+				bnode.done = true
 			}
 
 		}
@@ -911,7 +918,7 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 		Bqueue = SetKey{}
 		for k := range Aqueue {
 			Adone.Add(k)
-			abucket, ok, err := av.GetToBucket(ctx, k)
+			abucket, ok, err := av.GetToLeaf(ctx, k)
 			if err != nil {
 				return nil, err
 			}
@@ -920,6 +927,8 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 				continue // key not covered
 			}
 
+			// XXX check for anode.node.(*Tree)	(ø tree case)
+
 			// - bucket if not already done
 			// XXX also extract holes
 			if !abucket.done {