From ca4a23bc3c088b6a0222f7bf2c2bae5a3d7f9959 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Sat, 4 Mar 2023 09:42:44 -0700
Subject: btrfsutil: RebuiltForrest: Naively implement the new btrfs.ReadableFS
 API

---
 lib/btrfsutil/rebuilt_forrest.go | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

(limited to 'lib/btrfsutil/rebuilt_forrest.go')

diff --git a/lib/btrfsutil/rebuilt_forrest.go b/lib/btrfsutil/rebuilt_forrest.go
index a4ae727..b935d85 100644
--- a/lib/btrfsutil/rebuilt_forrest.go
+++ b/lib/btrfsutil/rebuilt_forrest.go
@@ -12,6 +12,7 @@ import (
 
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfstree"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
 	"git.lukeshu.com/btrfs-progs-ng/lib/maps"
@@ -172,7 +173,7 @@ func (ts *RebuiltForrest) rebuildTree(ctx context.Context, treeID btrfsprim.ObjI
 	default:
 		rootOff, rootItem, ok := ts.cb.LookupRoot(ctx, treeID)
 		if !ok {
-			ts.trees[treeID].rootErr = fmt.Errorf("failed to look up ROOT_ITEM")
+			ts.trees[treeID].rootErr = btrfstree.ErrNoTree
 			return
 		}
 		root = rootItem.ByteNr
@@ -228,3 +229,40 @@ func (ts *RebuiltForrest) RebuiltListRoots(ctx context.Context) map[btrfsprim.Ob
 	}
 	return ret
 }
+
+// btrfs.ReadableFS interface //////////////////////////////////////////////////////////////////////////////////////////
+
+var _ btrfs.ReadableFS = (*RebuiltForrest)(nil)
+
+// Name implements btrfs.ReadableFS.
+func (ts *RebuiltForrest) Name() string {
+	return ts.inner.Name()
+}
+
+// ForrestLookup implements btrfstree.Forrest (and btrfs.ReadableFS).
+//
+// It is identical to .RebuiltTree(), but returns an interface rather
+// than a concrete type.
+func (ts *RebuiltForrest) ForrestLookup(ctx context.Context, treeID btrfsprim.ObjID) (btrfstree.Tree, error) {
+	return ts.RebuiltTree(ctx, treeID)
+}
+
+// Superblock implements btrfstree.NodeSource (and btrfs.ReadableFS).
+func (ts *RebuiltForrest) Superblock() (*btrfstree.Superblock, error) {
+	return ts.inner.Superblock()
+}
+
+// AcquireNode implements btrfstree.NodeSource (and btrfs.ReadableFS).
+func (ts *RebuiltForrest) AcquireNode(ctx context.Context, addr btrfsvol.LogicalAddr, exp btrfstree.NodeExpectations) (*btrfstree.Node, error) {
+	return ts.inner.AcquireNode(ctx, addr, exp)
+}
+
+// ReleaseNode implements btrfstree.NodeSource (and btrfs.ReadableFS).
+func (ts *RebuiltForrest) ReleaseNode(node *btrfstree.Node) {
+	ts.inner.ReleaseNode(node)
+}
+
+// ReadAt implements diskio.ReaderAt[btrfsvol.LogicalAddr] (and btrfs.ReadableFS).
+func (ts *RebuiltForrest) ReadAt(p []byte, off btrfsvol.LogicalAddr) (int, error) {
+	return ts.inner.ReadAt(p, off)
+}
-- 
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