.

wcfs/wcfs.go

@@ -863,9 +863,9 @@ retry:
 		return err
 	}
 
-	if false { // XXX -> V(2) ?
+	if !log.V(2) {
 		// debug dump δF
-		fmt.Printf("\n\nS: handleδZ: δF (#%d):\n", len(δF.ByFile))
+		log.Infof("\n\nS: handleδZ: δF (#%d):\n", len(δF.ByFile))
 		for file, δfile := range δF.ByFile {
 			blkv := δfile.Blocks.Elements()
 			sort.Slice(blkv, func(i, j int) bool {
@@ -875,9 +875,9 @@ retry:
 			if δfile.Size {
 				size = "S"
 			}
-			fmt.Printf("S: \t- %s\t%s %v\n", file.zfile.POid(), size, blkv)
+			log.Infof("S: \t- %s\t%s %v\n", file.zfile.POid(), size, blkv)
 		}
-		fmt.Printf("\n\n")
+		log.Infof("\n\n")
 	}
 
 	wg := xsync.NewWorkGroup(ctx)

wcfs/δbtail.go

@@ -120,7 +120,7 @@ type ΔValue struct {
 // It semantically consists of
 //
 //	[]δB			; rev ∈ (tail, head]
-//	atTail
+//	atTail					XXX no need (see vvv)
 //
 // where δB represents a change in BTrees space
 //
@@ -154,10 +154,11 @@ type ΔValue struct {
 // that ∈ BTree subgraphs that were explicitly requested to be tracked by δB.
 //
 // XXX incremental; not full coverage
-// XXX see also zodb.ΔTail .
 //
 // ΔBtail is not safe for concurrent access.
 // XXX -> multiple readers / single writer?
+//
+// See also zodb.ΔTail
 type ΔBtail struct {
 	// raw ZODB changes; Kept to rebuild δBtail/byRoot after new Track.
 	// includes all changed objects, not only tracked ones.
@@ -347,8 +348,8 @@ type ΔTree struct {
 // Initial tracked set is empty.
 // Initial coverage is (at₀, at₀].
 //
-// db will be used by ΔBtail to open database connections ... XXX
-// XXX or caller provides zhead/zprev explicitly?
+// db will be used by ΔBtail to open database connections to load data from
+// ZODB when needed.   XXX or caller provides zhead/zprev explicitly?
 func NewΔBtail(at0 zodb.Tid, db *zodb.DB) *ΔBtail {
 	return &ΔBtail{
 		δZtail:        zodb.NewΔTail(at0),

wcfs/δftail.go

@@ -24,6 +24,7 @@ package main
 
 import (
 	"context"
+	"fmt"
 	"runtime"
 	"sync"
 
@@ -95,7 +96,6 @@ type ΔFile struct {
 	Size   bool   // whether file size changed
 }
 
-
 // zblkInΔFtail is ΔFtail-related volatile data embedded into ZBlk*.
 //
 // The data is preserved even when ZBlk comes to ghost state, but is lost if
@@ -120,7 +120,8 @@ func (z *zblkInΔFtail) inΔFtail() *zblkInΔFtail { return z }
 // Initial tracked set is empty.
 // Initial coverage of created ΔFtail is (at₀, at₀].
 //
-// XXX db
+// db will be used by ΔFtail to open database connections to load data from
+// ZODB when needed.
 func NewΔFtail(at0 zodb.Tid, db *zodb.DB) *ΔFtail {
 	return &ΔFtail{
 		δBtail:   NewΔBtail(at0, db),
@@ -134,7 +135,7 @@ func (δFtail *ΔFtail) Head() zodb.Tid { return δFtail.δBtail.Head() }
 func (δFtail *ΔFtail) Tail() zodb.Tid { return δFtail.δBtail.Tail() }
 
 
-// Track associates file[blk] with tree path and zblk object there.
+// Track associates file[blk]@head with tree path and zblk object.
 //
 // zblk can be nil, which represents a hole.
 // XXX blk=-1 is used for tracking after Size (no zblk is accessed at all).
@@ -143,6 +144,8 @@ func (δFtail *ΔFtail) Tail() zodb.Tid { return δFtail.δBtail.Tail() }
 //
 // XXX text
 //
+// XXX objects in path and zblk must be with .PJar().At() == .head
+//
 // A root can be associated with several files (each provided on different Track call).
 func (δFtail *ΔFtail) Track(file *BigFile, blk int64, path []btree.LONode, zblk ZBlk) {
 	if blk == -1 {
@@ -225,7 +228,7 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit, zhead *ZConn) (_ ΔF, err
 	for root, δt := range δB.ByRoot {
 		files := δFtail.fileIdx[root]
 		if len(files) == 0 {
-			panicf("ΔFtail: root<%s> -> ø file", root)
+			panicf("BUG: ΔFtail: root<%s> -> ø files", root)
 		}
 		for file := range files {
 			δfile, ok := δF.ByFile[file]
@@ -277,11 +280,10 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit, zhead *ZConn) (_ ΔF, err
 			// XXX update z.infile according to btree changes
 
 		case *ZBigFile:
-			// XXX check that .blksize and .blktab (it is only
+			// TODO check that .blksize and .blktab (it is only
 			// persistent reference) do not change.
 
-			// XXX shutdown fs with ^^^ message.
-			panic("ZBigFile changed")
+			return ΔF{}, fmt.Errorf("ZBigFile<%s> changed @%s", oid, δZ.Tid)
 		}
 
 		// make sure obj won't be garbage-collected until we finish handling it.