Merge branch 'lukeshu/errs'

1 files changed, 32 insertions, 0 deletions

diff --git a/lib/btrfs/btrfstree/btree_err.go b/lib/btrfs/btrfstree/btree_err.go
new file mode 100644
index 0000000..57fb283
--- /dev/null
+++ b/lib/btrfs/btrfstree/btree_err.go
@@ -0,0 +1,32 @@
+// Copyright (C) 2023  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package btrfstree
+
+import (
+	iofs "io/fs"
+)
+
+// For both ErrNoItem and ErrNoTree, `errors.Is(err,
+// io/fs.ErrNotExist)` returns true.
+var (
+	ErrNoItem = errNotExist("item")
+	ErrNoTree = errNotExist("tree")
+)
+
+func errNotExist(thing string) error {
+	return &notExistError{thing}
+}
+
+type notExistError struct {
+	thing string
+}
+
+func (e *notExistError) Error() string {
+	return e.thing + " does not exist"
+}
+
+func (*notExistError) Is(target error) bool {
+	return target == iofs.ErrNotExist
+}