func detectBaseLayer(is image.Store, m *schema1.Manifest, rootFS *image.RootFS) error {
v1img := &image.V1Image{}
if err := json.Unmarshal([]byte(m.History[len(m.History)-1].V1Compatibility), v1img); err != nil {
return err
}
if v1img.Parent == "" {
return fmt.Errorf("Last layer %q does not have a base layer reference", v1img.ID)
}
// There must be an image that already references the baselayer.
for _, img := range is.Map() {
if img.RootFS.BaseLayerID() == v1img.Parent {
rootFS.BaseLayer = img.RootFS.BaseLayer
return nil
}
}
return fmt.Errorf("Invalid base layer %q", v1img.Parent)
}
