func splitFiles()

in txtar.go [80:117]
38 lines of code
13 McCabe index (conditional complexity)

func splitFiles(src []byte) (*fileSet, error) {
	fs := new(fileSet)
	a := txtar.Parse(src)
	if v := bytes.TrimSpace(a.Comment); len(v) > 0 {
		fs.noHeader = true
		fs.AddFile(progName, a.Comment)
	}
	const limitNumFiles = 20 // arbitrary
	numFiles := len(a.Files) + fs.Num()
	if numFiles > limitNumFiles {
		return nil, fmt.Errorf("too many files in txtar archive (%v exceeds limit of %v)", numFiles, limitNumFiles)
	}
	for _, f := range a.Files {
		if len(f.Name) > 200 { // arbitrary limit
			return nil, errors.New("file name too long")
		}
		if strings.IndexFunc(f.Name, isBogusFilenameRune) != -1 {
			return nil, fmt.Errorf("invalid file name %q", f.Name)
		}
		if f.Name != path.Clean(f.Name) || path.IsAbs(f.Name) {
			return nil, fmt.Errorf("invalid file name %q", f.Name)
		}
		parts := strings.Split(f.Name, "/")
		if len(parts) > 10 { // arbitrary limit
			return nil, fmt.Errorf("file name %q too deep", f.Name)
		}
		for _, part := range parts {
			if part == "." || part == ".." {
				return nil, fmt.Errorf("invalid file name %q", f.Name)
			}
		}
		if fs.Contains(f.Name) {
			return nil, fmt.Errorf("duplicate file name %q", f.Name)
		}
		fs.AddFile(f.Name, f.Data)
	}
	return fs, nil
}