Function parseDefFile

sif/load.go:22–57

parseDefFile parses a SIF definition file from reader, and returns non-trivial contents of the %environment and %runscript sections.

(reader io.Reader)

// parseDefFile parses a SIF definition file from reader,
// and returns non-trivial contents of the %environment and %runscript sections.
func parseDefFile(reader io.Reader) ([]string, []string, error) {
	type parserState int
	const (
		parsingOther parserState = iota
		parsingEnvironment
		parsingRunscript
	)

	environment := []string{}
	runscript := []string{}

	state := parsingOther
	scanner := bufio.NewScanner(reader)
	for scanner.Scan() {
		s := strings.TrimSpace(scanner.Text())
		switch {
		case s == `%environment`:
			state = parsingEnvironment
		case s == `%runscript`:
			state = parsingRunscript
		case strings.HasPrefix(s, "%"):
			state = parsingOther
		case state == parsingEnvironment:
			if s != "" && !strings.HasPrefix(s, "#") {
				environment = append(environment, s)
			}
		case state == parsingRunscript:
			runscript = append(runscript, s)
		default: // parsingOther: ignore the line
		}
	}
	if err := scanner.Err(); err != nil {
		return nil, nil, fmt.Errorf("reading lines from SIF definition file object: %w", err)
	}
	return environment, runscript, nil
}

// generateInjectedScript generates a shell script based on
// SIF definition file %environment and %runscript data, and returns it.