.

wcfs/internal/xbtree/δbtail.go

@@ -35,7 +35,7 @@ type Bucket = btree.LOBucket
 type Node   = btree.LONode
 type Key    = int64
 
-// ΔTail reprsents tail of revisional changes to BTrees.
+// ΔTail represents tail of revisional changes to BTrees.
 //
 // It semantically consists of
 //
@@ -48,7 +48,7 @@ type Key    = int64
 // that ∈ BTree subgraphs that were explicitly requested to be tracked by δB.
 //
 // XXX incremental; not full coverage
-// XXX concurency safety
+// XXX concurrency safety
 type ΔTail struct {
 	//at // = head
 	δZtail *zodb.ΔTail
@@ -69,12 +69,14 @@ type ΔRevEntry struct {
 
 // ΔTree represents changes to one tree.
 type ΔTree struct {
-	Root XXX
+	Root XXX	// XXX -> Oid?
 	Keyv []Key
 }
 
 // Track adds tree path to tracked set.
 //
+// XXX tailv is rebuild to also include keys corresponding to added nodes.
+//
 // XXX path is at @at state.
 // XXX objects in path must be with .PJar().At() == .head
 // XXX path -> []oid ?
@@ -89,7 +91,8 @@ func (δb *ΔTail) Track(path []Node) {	// XXX Tree|Bucket; path[0] = root
 // Update updates δB with per-object level ZODB changes.
 //
 // Only those objects from δZ that belong to tracked set are guaranteed to be
-// taken into account.
+// taken into account. In other words a tree history will assuredly include
+// only those keys, that correspond to tracked subset of δZ.
 //
 // XXX return -> [] of (root, []key) that are invalidated.
 // XXX -> + separate SliceByRev? or Data to get diff?