Merge branch 'lukeshu/tree-api-pt0-prep'

1 files changed, 36 insertions, 34 deletions

diff --git a/lib/btrfs/btrfstree/btree.go b/lib/btrfs/btrfstree/btree.go
index e91fcc1..bc1bac2 100644
--- a/lib/btrfs/btrfstree/btree.go
+++ b/lib/btrfs/btrfstree/btree.go
@@ -22,30 +22,51 @@ type TreeSearcher interface {
 	Search(key btrfsprim.Key, size uint32) int
 }
 
+type TreeWalkHandler struct {
+	BadSuperblock func(error)
+
+	// Callbacks for entire nodes.
+	//
+	// The return value from BadNode is whether to process the
+	// slots in this node or not; if no BadNode function is given,
+	// then it is not processed.
+	Node    func(Path, *Node)
+	BadNode func(Path, *Node, error) bool
+
+	// Callbacks for slots in nodes.
+	//
+	// The return value from KeyPointer is whether to recurse or
+	// not; if no KeyPointer function is given, then it is
+	// recursed.
+	KeyPointer func(Path, KeyPointer) bool
+	Item       func(Path, Item)
+	BadItem    func(Path, Item)
+}
+
 // TreeOperator is an interface for performing basic btree operations.
 type TreeOperator interface {
 	// TreeWalk walks a tree, triggering callbacks for every node,
 	// key-pointer, and item; as well as for any errors encountered.
 	//
-	// If the tree is valid, then everything is walked in key-order; but if
-	// the tree is broken, then ordering is not guaranteed.
+	// If the tree is valid, then everything is walked in key-order; but
+	// if the tree is broken, then ordering is not guaranteed.
 	//
-	// Canceling the Context causes TreeWalk to return early; no
-	// values from the Context are used.
+	// Canceling the Context causes TreeWalk to return early; no values
+	// from the Context are used.
 	//
 	// The lifecycle of callbacks is:
 	//
-	//     001 .PreNode()
-	//     002 (read node)
-	//     003 .Node() (or .BadNode())
-	//         for item in node.items:
-	//           if interior:
-	//     004     .PreKeyPointer()
-	//     005     (recurse)
-	//     006     .PostKeyPointer()
-	//           else:
-	//     004     .Item() (or .BadItem())
-	//     007 .PostNode()
+	//	000  (read superblock) (maybe cbs.BadSuperblock())
+	//
+	//	001  (read node)
+	//	002  cbs.Node() or cbs.BadNode()
+	//	     if interior:
+	//	       for kp in node.items:
+	//	003a     if cbs.PreKeyPointer == nil || cbs.PreKeyPointer() {
+	//	004b       (recurse)
+	//	     else:
+	//	       for item in node.items:
+	//	003b     cbs.Item() or cbs.BadItem()
 	TreeWalk(ctx context.Context, treeID btrfsprim.ObjID, errHandle func(*TreeError), cbs TreeWalkHandler)
 
 	TreeLookup(treeID btrfsprim.ObjID, key btrfsprim.Key) (Item, error)
@@ -62,25 +83,6 @@ type TreeOperator interface {
 	TreeSearchAll(treeID btrfsprim.ObjID, search TreeSearcher) ([]Item, error)
 }
 
-type TreeWalkHandler struct {
-	// Callbacks for entire nodes.
-	//
-	// If any of these return an error that is io/fs.SkipDir, the
-	// node immediately stops getting processed; if PreNode, Node,
-	// or BadNode return io/fs.SkipDir then key pointers and items
-	// within the node are not processed.
-	PreNode  func(Path) error
-	Node     func(Path, *Node) error
-	BadNode  func(Path, *Node, error) error
-	PostNode func(Path, *Node) error
-	// Callbacks for items on interior nodes
-	PreKeyPointer  func(Path, KeyPointer) error
-	PostKeyPointer func(Path, KeyPointer) error
-	// Callbacks for items on leaf nodes
-	Item    func(Path, Item) error
-	BadItem func(Path, Item) error
-}
-
 type TreeError struct {
 	Path Path
 	Err  error