1 files changed, 53 insertions, 0 deletions
diff --git a/repository/tree.go b/repository/tree.go
new file mode 100644
index 00000000..d4ef529e
--- /dev/null
+++ b/repository/tree.go
@@ -0,0 +1,53 @@
+package repository
+
+import (
+	"errors"
+	"fmt"
+
+	"codeberg.org/lindenii/furgit/object"
+	"codeberg.org/lindenii/furgit/objectstored"
+)
+
+// ResolveTreeEntry resolves one path within a stored root tree.
+//
+// parts must contain at least one path segment. Intermediate segments must be
+// tree entries.
+func (repo *Repository) ResolveTreeEntry(tree *objectstored.StoredTree, parts [][]byte) (object.TreeEntry, error) {
+	if tree == nil {
+		return object.TreeEntry{}, errors.New("repository: nil root tree")
+	}
+
+	if len(parts) == 0 {
+		return object.TreeEntry{}, errors.New("repository: empty tree path")
+	}
+
+	current := tree
+
+	for i, part := range parts {
+		if len(part) == 0 {
+			return object.TreeEntry{}, errors.New("repository: empty tree path segment")
+		}
+
+		entry := current.Tree().Entry(part)
+		if entry == nil {
+			return object.TreeEntry{}, fmt.Errorf("repository: tree entry %q not found", part)
+		}
+
+		if i == len(parts)-1 {
+			return *entry, nil
+		}
+
+		if entry.Mode != object.FileModeDir {
+			return object.TreeEntry{}, fmt.Errorf("repository: path segment %q is not a tree", part)
+		}
+
+		next, err := repo.ReadStoredTree(entry.ID)
+		if err != nil {
+			return object.TreeEntry{}, err
+		}
+
+		current = next
+	}
+
+	return object.TreeEntry{}, fmt.Errorf("repository: tree entry not found")
+}