func updateConfigLayers()

in container/go/pkg/compat/config.go [397:440]

• 37 lines of code
• 9 McCabe index (conditional complexity)

func updateConfigLayers(overrideInfo *OverrideConfigOpts, layerDigests []string, creationTime time.Time) error {
	// diffIDs are ordered from bottom-most to top-most.
	diffIDs := []v1.Hash{}
	if len(overrideInfo.ConfigFile.RootFS.DiffIDs) > 0 {
		diffIDs = overrideInfo.ConfigFile.RootFS.DiffIDs
	}
	if len(overrideInfo.Layer) > 0 {
		var diffIDToAdd v1.Hash
		for _, diffID := range layerDigests {
			if diffID != emptySHA256Digest() {
				diffIDToAdd = v1.Hash{Algorithm: "sha256", Hex: diffID}
				diffIDs = append(diffIDs, diffIDToAdd)
			}
		}
		overrideInfo.ConfigFile.RootFS = v1.RootFS{Type: "layers", DiffIDs: diffIDs}

		// length of history is expected to match the length of diff_ids.
		history := []v1.History{}
		if len(overrideInfo.ConfigFile.History) > 0 {
			history = overrideInfo.ConfigFile.History
		}
		var historyToAdd v1.History

		for _, l := range layerDigests {
			if err := overrideInfo.validate(); err != nil {
				return errors.Wrapf(err, "unable to create a new config because the given options to override the existing image config/generate new config failed validation")
			}

			historyToAdd = v1.History{
				Author:    overrideInfo.Author,
				Created:   v1.Time{creationTime},
				CreatedBy: overrideInfo.CreatedBy,
			}
			if l == emptySHA256Digest() {
				historyToAdd.EmptyLayer = true
			}
			// prepend to history list.
			history = append([]v1.History{historyToAdd}, history...)
		}
		overrideInfo.ConfigFile.History = history
	}

	return nil
}