.

wcfs/internal/zdata/δftail.go

@@ -538,14 +538,21 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 //
 // XXX +ctx, error	rebuild []δF here
 func (δFtail *ΔFtail) LastBlkRev(ctx context.Context, zf *ZBigFile, blk int64, at zodb.Tid) (_ zodb.Tid, exact bool) {
-	//defer xerr.Contextf(&err, "")	// XXX text
+	rev, exact, err := δFtail._LastBlkRev(ctx, zf, blk, at)
+	if err != nil {
+		panic(err) // XXX
+	}
+	return rev, exact
+}
+func (δFtail *ΔFtail) _LastBlkRev(ctx context.Context, zf *ZBigFile, blk int64, at zodb.Tid) (_ zodb.Tid, exact bool, err error) {
+	defer xerr.Contextf(&err, "blkrev f<%s> #%d @%s", zf.POid(), blk, at)
 
 	// XXX locking
 	// XXX rebuild
 
 	δftail := δFtail.byFile[zf.POid()]
 
-	// find epoch that covers at
+	// find epoch that covers at and associated blktab root/object
 	vδE := δftail.vδE
 	l := len(vδE)
 	i := sort.Search(l, func(i int) bool {
@@ -553,13 +560,30 @@ func (δFtail *ΔFtail) LastBlkRev(ctx context.Context, zf *ZBigFile, blk int64,
 	})
 	// vδE[i]   is next epoch
 	// vδE[i-1] is epoch that covers at
+
+	// root
 	var root    zodb.Oid
-	var epoch zodb.Tid
+	var rootObj *btree.LOBTree
 	if i == l {
-		root = zf.blktab // XXX activate
+		err := zf.PActivate(ctx)
+		if err != nil {
+			// file deleted
+			if xzodb.IsErrNoData(err) {
+				root = xbtree.VDEL
+			} else {
+				return zodb.InvalidTid, false, err
+			}
+		} else {
+			rootObj = zf.blktab
+			root = rootObj.POid()
+			zf.PDeactivate()
+		}
 	} else {
 		root = vδE[i].oldRoot
 	}
+
+	// epoch
+	var epoch zodb.Tid
 	i--
 	if i < 0 {
 		// i<0 - first epoch (no explicit start) - use δFtail.tail as lo
@@ -568,26 +592,31 @@ func (δFtail *ΔFtail) LastBlkRev(ctx context.Context, zf *ZBigFile, blk int64,
 		epoch = vδE[i].Rev
 	}
 
-	//root := δftail.root // XXX handle epochs
-
-	err := zf.PActivate(ctx)
+	// get to rootObj  (NOTE @head, because it is ΔBtail.GetAt requirement)
+	if rootObj == nil && root != xbtree.VDEL {
+		zconn := zf.PJar()
+		xrootObj, err := zconn.Get(ctx, root)
 		if err != nil {
-		// file deleted
-		if xzodb.IsErrNoData(err) {
-			return δFtail.Tail(), false // FIXME tail -> epoch(at)
+			return zodb.InvalidTid, false, err
+		}
+		var ok bool
+		rootObj, ok = xrootObj.(*btree.LOBTree)
+		if !ok {
+			return zodb.InvalidTid, false, fmt.Errorf("blktab: expect LOBTree; got %s", xzodb.TypeOf(xrootObj))
 		}
-		panic(err) // XXX
 	}
-	defer zf.PDeactivate()
 
 	// XXX take epochs into account
 
-	// XXX tabRev -> treeRev ?
-	//zblkOid, ok, tabRev, tabRevExact, err := δFtail.δBtail.GetAt(ctx, root, blk, at)
-	zblkOid, ok, tabRev, tabRevExact, err := δFtail.δBtail.GetAt(ctx, zf.blktab, blk, at)
+	var zblkOid zodb.Oid
+	var tabRev  zodb.Tid
+	var tabRevExact, ok bool
+	if rootObj != nil {
+		zblkOid, ok, tabRev, tabRevExact, err = δFtail.δBtail.GetAt(ctx, rootObj, blk, at)
 		//fmt.Printf("GetAt  #%d @%s  ->  %s, %v, @%s, %v\n", blk, at, zblkOid, ok, tabRev, tabRevExact)
 		if err != nil {
-		panic(err) // XXX
+			return zodb.InvalidTid, false, err
+		}
 	}
 
 	if tabRev < epoch {
@@ -595,9 +624,8 @@ func (δFtail *ΔFtail) LastBlkRev(ctx context.Context, zf *ZBigFile, blk int64,
 	}
 
 	// block was removed
-	// XXX or not in tracked set?
 	if !ok {
-		return tabRev, tabRevExact
+		return tabRev, tabRevExact, nil
 	}
 
 	// blktab[blk] was changed to point to a zblk @rev.
@@ -605,9 +633,9 @@ func (δFtail *ΔFtail) LastBlkRev(ctx context.Context, zf *ZBigFile, blk int64,
 	zblkRev, zblkRevExact := δFtail.δBtail.ΔZtail().LastRevOf(zblkOid, at)
 	//fmt.Printf("ZRevOf %s @%s -> @%s, %v\n", zblkOid, at, zblkRev, zblkRevExact)
 	if zblkRev > tabRev {
-		return zblkRev, zblkRevExact
+		return zblkRev, zblkRevExact, nil
 	} else {
-		return tabRev, tabRevExact
+		return tabRev, tabRevExact, nil
 	}
 }