iterator technique for unixfs dir listing

License: MIT
Signed-off-by: Jeromy <why@ipfs.io>

hamt/hamt.go

@@ -321,22 +321,24 @@ func (ds *HamtShard) getValue(ctx context.Context, hv *hashBits, key string, cb
 
 func (ds *HamtShard) EnumLinks() ([]*node.Link, error) {
 	var links []*node.Link
-	err := ds.walkTrie(func(sv *shardValue) error {
+	err := ds.ForEachLink(func(l *node.Link) error {
+		links = append(links, l)
+		return nil
+	})
+	return links, err
+}
+
+func (ds *HamtShard) ForEachLink(f func(*node.Link) error) error {
+	return ds.walkTrie(func(sv *shardValue) error {
 		lnk, err := node.MakeLink(sv.val)
 		if err != nil {
 			return err
 		}
 
 		lnk.Name = sv.key
 
-		links = append(links, lnk)
-		return nil
+		return f(lnk)
 	})
-	if err != nil {
-		return nil, err
-	}
-
-	return links, nil
 }
 
 func (ds *HamtShard) walkTrie(cb func(*shardValue) error) error {

io/dirbuilder.go

@@ -102,6 +102,19 @@ func (d *Directory) switchToSharding(ctx context.Context) error {
 	return nil
 }
 
+func (d *Directory) ForEachLink(f func(*node.Link) error) error {
+	if d.shard == nil {
+		for _, l := range d.dirnode.Links() {
+			if err := f(l); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	return d.shard.ForEachLink(f)
+}
+
 func (d *Directory) Links() ([]*node.Link, error) {
 	if d.shard == nil {
 		return d.dirnode.Links(), nil