.

wcfs/internal/xbtree/δbtail.go

@@ -60,24 +60,24 @@ const debugΔBtail = false
 //
 //   .Update(δZ) -> δB				- update BTree δ tail given raw ZODB changes
 //   .ForgetPast(revCut)			- forget changes past revCut
-//   .SliceByRev(lo, hi) -> []δB		- XXX
-//   .SliceByRootRev(root, lo, hi) -> []δT	- XXX
+//   .SliceByRev(lo, hi) -> []δB		- query for all trees changes with rev ∈ (lo, hi]
+//   .SliceByRootRev(root, lo, hi) -> []δT	- query for changes of a tree with rev ∈ (lo, hi]
 //
 // XXX also:
 //   .Get(root, key, at)			- get root[key] @at assuming root[key] ∈ tracked
 //
-// An example for tracked set is a set of visited BTree paths.
-// There is no requirement that tracked set belongs to only one single BTree.
+// where δT represents a change to one tree
 //
-// XXX δB can convert δZ to btree changes, but only at least for δZ's objects
-// that ∈ BTree subgraphs that were explicitly requested to be tracked by δB.
+//	δT:
+//		.rev↑
+//		{}(key, δvalue)
 //
-// XXX incremental; not full coverage
+// An example for tracked set is a set of visited BTree paths.
+// There is no requirement that tracked set belongs to only one single BTree.
 //
-// ΔBtail is not safe for concurrent access.	XXX rework
-// XXX -> multiple readers / single writer?
+// XXX concurrent use
 //
-// See also zodb.ΔTail
+// See also zodb.ΔTail and zdata.ΔFtail
 type ΔBtail struct {
 	// raw ZODB changes; Kept to rebuild .vδTbyRoot after new Track.
 	// includes all changed objects, not only tracked ones.

wcfs/internal/zdata/δftail.go

@@ -78,7 +78,7 @@ type setOid = set.Oid
 //
 // XXX concurrent use
 //
-// See also zodb.ΔTail
+// See also zodb.ΔTail and xbtree.ΔBtail
 type ΔFtail struct {
 	// ΔFtail merges ΔBtail with history of ZBlk
 	δBtail  *xbtree.ΔBtail