.

wcfs/internal/xbtree/δbtail.go

@@ -38,6 +38,12 @@ type Key    = int64
 type Value  = zodb.Oid // XXX assumes key points to IPersistent
                        // XXX how to represent deletion? InvalidOid?
 
+// XXX
+//
+//	δB:
+//		.rev↑
+//		{} root -> {}(key, value)
+
 // ΔTail represents tail of revisional changes to BTrees.
 //
 // It covers changes to keys from tracked subset of BTrees parts and
@@ -59,9 +65,9 @@ type Value  = zodb.Oid // XXX assumes key points to IPersistent
 // It provides the following operations:
 //
 //   - Track(path)		- start tracking tree nodes and keys; root=path[0], keys=path[-1].keys
+//   - ForgetPast(revCut)	- forget changes past revCut
 //   - Get(root, key, at)	- get root[key] @at assuming root[key] ∈ tracked
 //   - Update(δZ)		- update BTree δ tail given raw ZODB changes
-//   - ForgetPast(revCut)	- forget changes past revCut
 //
 // 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.

wcfs/wcfs.go

@@ -402,10 +402,10 @@ package main
 
 // XXX notation
 //
-// δZ    - changes in ZODB space
-// δB    - changes in BTree*s* space
-// δF    - changes in File*s* space
-// δfile - changes in File(1) space
+// δZ    - change in ZODB space
+// δB    - change in BTree*s* space
+// δF    - change in File*s* space
+// δfile - change in File(1) space
 
 import (
 	"bufio"
@@ -801,9 +801,9 @@ retry:
 	//fmt.Printf("\nbtreeChangev: %v\n", btreeChangev)
 	δf := bfdir.δFtail.Update(δZ)
 	//fmt.Printf("xfiles: %v\n", xfiles)
-	for _, δ := range δf.Changev {
-		file := δ.File
-		// XXX use δ.Blkv
+	for file, δfile := range δf.Change {
+		// XXX use δfile blocks
+		_ = δfile
 		finv, ok := toinvalidate[file]
 		if !ok {
 			finv = &fileInvalidate{} // XXX init blkmap?

wcfs/δftail.go

@@ -27,21 +27,39 @@ import (
 	"./internal/xbtree"
 )
 
-// ΔFTail is like btree.ΔTail but additionally tracks tree-root -> file relation and
-// takes ZBlk history into account.
+// ΔFtail represents tail of revisional changes to files.
+//
+// It semantically consists of
+//
+//	[]δF			; rev ∈ (tail, head]
+//
+// where δF represents a change in files space
+//
+//	δF:
+//		.rev↑
+//		[](file, []blk)
+//
+// It provides the following operations:
+//
+//   .Update(δZ) -> δF				- update files δ tail given raw ZODB changes
+//   .ForgetPast(revCut)			- forget changes past revCut
+//   .Track			XXX
+//   .SliceByRev(lo, hi) -> []δF		- query for all changes with rev ∈ (lo, hi]
+//   .SliceByFileRev(file, lo, hi) -> []δfile	- query for changes of file with rev ∈ (lo, hi]
+//   .LastBlkRev(file, #blk, at)		- query for what is last revision that
+//						  changed file[#blk] as of @at database state.
+//
+//
+// XXX only tracked blocks.
 type ΔFTail struct {
 	*xbtree.ΔTail
 	fileIdx map[*btree.LOBTree]SetBigFile	// root -> {} BigFile	XXX root -> oid?
 }
 
-type ΔFentry struct {
+// ΔF represents a change in files space.
+type ΔF struct {
 	Rev     zodb.Tid
-	Changev []ΔFile
-}
-
-type ΔFile struct {
-	File *BigFile
-	Blkv []int64
+	Change	map[*BigFile]SetI64 // file -> δfile (= {}#blk)
 }
 
 func NewΔFTail(at0 zodb.Tid) *ΔFTail {
@@ -65,33 +83,32 @@ func (δf *ΔFTail) Track(file *BigFile, path []btree.LONode) {
 	files.Add(file)
 }
 
-// XXX
-func (δf *ΔFTail) Update(δZ *zodb.EventCommit) ΔFentry {
-	δB := δf.ΔTail.Update(δZ)
-	var changev []ΔFile // δB root -> file (via .fileIdx)
-	for _, δ := range δB {
-		files := δf.fileIdx[δ.Root]
+// Update updates δFtail given raw ZODB changes.
+//
+// It returns corresponding change in files space.
+func (δFtail *ΔFTail) Update(δZ *zodb.EventCommit) ΔF {
+	δB := δFtail.ΔTail.Update(δZ)
+	δF := ΔF{Rev: δB.Rev, Change: make(map[*BigFile]SetI64)}
+	for root, δt := range δB {
+		files := δFtail.fileIdx[root]
 		if len(files) == 0 {
-			panicf("ΔFTail: root<%s> -> ø file", δ.Root.POid())
+			panicf("ΔFTail: root<%s> -> ø file", root.POid())
 		}
 		for file := range files {
-			var blkv []int64
-			for blk /*, zblk*/ := range δ.KV {
+			δfile, ok := δF.Change[file]
+			if !ok {
+				δfile = make(SetI64)
+				δF.Change[file] = δfile
+			}
+			for blk /*, zblk*/ := range δt.KV {
 				// FIXME stub - need to take both keys and zblk changes into account
 				// XXX document, and in particular how to include atTail
-				blkv = append(blkv, blk)
+				δfile.Add(blk)
 			}
-			changev = append(changev, ΔFile{
-				File: file,
-				Blkv: blkv,
-			})
 		}
 	}
 
-	return ΔFentry{
-		Rev:     δZ.Tid,
-		Changev: changev,
-	}
+	return δF
 }
 
 // LastBlkRev returns last revision that changed file[blk] as of @at database state.