func runCTags()

in build/ctags.go [31:111]
71 lines of code
17 McCabe index (conditional complexity)

func runCTags(bin string, inputs map[string][]byte) ([]*ctags.Entry, error) {
	const debug = false
	if len(inputs) == 0 {
		return nil, nil
	}
	dir, err := ioutil.TempDir("", "ctags-input")
	if err != nil {
		return nil, err
	}
	if !debug {
		defer os.RemoveAll(dir)
	}

	// --sort shells out to sort(1).
	args := []string{bin, "-n", "-f", "-", "--sort=no"}

	fileCount := 0
	for n, c := range inputs {
		if len(c) == 0 {
			continue
		}

		full := filepath.Join(dir, n)
		if err := os.MkdirAll(filepath.Dir(full), 0o700); err != nil {
			return nil, err
		}
		err := ioutil.WriteFile(full, c, 0o600)
		if err != nil {
			return nil, err
		}
		args = append(args, n)
		fileCount++
	}
	if fileCount == 0 {
		return nil, nil
	}

	cmd := exec.Command(args[0], args[1:]...)
	cmd.Dir = dir

	var errBuf, outBuf bytes.Buffer
	cmd.Stderr = &errBuf
	cmd.Stdout = &outBuf

	if err := cmd.Start(); err != nil {
		return nil, err
	}

	errChan := make(chan error, 1)
	go func() {
		err := cmd.Wait()
		errChan <- err
	}()
	timeout := time.After(5 * time.Second)
	select {
	case <-timeout:
		cmd.Process.Kill()
		return nil, fmt.Errorf("timeout executing ctags")
	case err := <-errChan:
		if err != nil {
			return nil, fmt.Errorf("exec(%s): %v, stderr: %s", cmd.Args, err, errBuf.String())
		}
	}

	var entries []*ctags.Entry
	for _, l := range bytes.Split(outBuf.Bytes(), []byte{'\n'}) {
		if len(l) == 0 {
			continue
		}
		e, err := ctags.Parse(string(l))
		if err != nil {
			return nil, err
		}

		if len(e.Sym) == 1 {
			continue
		}
		entries = append(entries, e)
	}
	return entries, nil
}