From 96230176e9d4b476ef106e6f40948a76f1dbb175 Mon Sep 17 00:00:00 2001
From: Justin Chadwell <me@jedevc.com>
Date: Wed, 14 Dec 2022 18:29:00 +0000
Subject: [PATCH] ociindex: add utility method for getting a single manifest
 from the index

Signed-off-by: Justin Chadwell <me@jedevc.com>
---
 client/ociindex/ociindex.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/client/ociindex/ociindex.go b/client/ociindex/ociindex.go
index b4db093798a2..3731ff36bb23 100644
--- a/client/ociindex/ociindex.go
+++ b/client/ociindex/ociindex.go
@@ -119,6 +119,18 @@ func (s StoreIndex) Get(tag string) (*ocispecs.Descriptor, error) {
 	return nil, nil
 }
 
+func (s StoreIndex) GetSingle() (*ocispecs.Descriptor, error) {
+	idx, err := s.Read()
+	if err != nil {
+		return nil, err
+	}
+
+	if len(idx.Manifests) == 1 {
+		return &idx.Manifests[0], nil
+	}
+	return nil, nil
+}
+
 // insertDesc puts desc to index with tag.
 // Existing manifests with the same tag will be removed from the index.
 func insertDesc(index *ocispecs.Index, desc ocispecs.Descriptor, tag string) error {