.

wcfs/internal/xbtree/δbtail.go

@@ -162,16 +162,26 @@ func (δb *ΔTail) Tail() zodb.Tid {
 // XXX objects in path must be with .PJar().At() == .head
 // XXX path -> []oid ?
 func (δb *ΔTail) Track(path []Node) {	// XXX Tree|Bucket; path[0] = root
-/*
-	root = path[0]
-	for obj in path:
-		if not obj in trackIdx:
-			.trackNew += obj
-		.trackIdx[obj] += root
-
-	XXX update diff	XXX here? or as separate step?
-	XXX update lastRevOf
-*/
+	l := len(path)
+	if l == 0 {
+		panic("empty path")
+	}
+	root := path[0].(*Tree)
+	// XXX assert Tree Tree ... Tree Bucket
+
+	for _, node := range path {
+		oid := node.POid()
+		nodeRoots, ok := δb.trackIdx[oid]
+		if !ok {
+			nodeRoots = make(SetTree)
+			δb.trackIdx[oid] = nodeRoots
+			// XXX .trackNew += oid
+		}
+		nodeRoots.Add(root)
+	}
+
+	// XXX update diff	XXX here? or as separate step?
+	// XXX update lastRevOf
 }
 
 // Update updates δB with per-object level ZODB changes.

wcfs/wcfs.go

@@ -522,7 +522,7 @@ type BigFile struct {
 	rev     zodb.Tid // last revision that modified zfile data
 
 //	// tail change history of this file.
-//	δtail *ΔTailI64 // [](rev↑, []#blk)
+	δtail *ΔTailI64 // [](rev↑, []#blk)	XXX kill
 
 	// inflight loadings of ZBigFile from ZODB.
 	// successful load results are kept here until blkdata is put into OS pagecache.
@@ -1696,8 +1696,8 @@ func (head *Head) bigopen(ctx context.Context, oid zodb.Oid) (_ *BigFile, err er
 		size:    size,
 		rev:     rev,
 
-		// XXX this is needed only for head/
-		δtail:   NewΔTailI64(zconn.At()),
+//		// XXX this is needed only for head/
+//		δtail:   NewΔTailI64(zconn.At()),
 		loading: make(map[int64]*blkLoadState),
 	}