func mapFind()

in dev/import-beats/common.go [91:129]

• 31 lines of code
• 7 McCabe index (conditional complexity)

func mapFind(
	key string,
	data mapStr,
	createMissing bool,
) (subKey string, subMap mapStr, oldValue interface{}, present bool, err error) {
	// XXX `safemapstr.mapFind` mimics this implementation, both should be updated to have similar behavior

	for {
		// Fast path, key is present as is.
		if v, exists := data[key]; exists {
			return key, data, v, true, nil
		}

		idx := strings.IndexRune(key, '.')
		if idx < 0 {
			return key, data, nil, false, nil
		}

		k := key[:idx]
		d, exists := data[k]
		if !exists {
			if createMissing {
				d = mapStr{}
				data[k] = d
			} else {
				return "", nil, nil, false, errKeyNotFound
			}
		}

		v, err := toMapStr(d)
		if err != nil {
			return "", nil, nil, false, err
		}

		// advance to sub-map
		key = key[idx+1:]
		data = v
	}
}