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package cli
import (
"io"
"io/ioutil"
"os"
)
// OpenInput is a convenience for possibly opening an input file, or otherwise returning standard in.
func OpenInput(filename string) (string, io.ReadCloser, error) {
if filename == "" {
return "<stdin>", ioutil.NopCloser(os.Stdin), nil
}
f, err := os.Open(filename)
return filename, f, err
}
// OpenOutput is a convenience for possibly opening an output file, or otherwise returning standard out.
func OpenOutput(filename string) (string, io.WriteCloser, error) {
if filename == "" {
return "<stdout>", nopwritercloser{os.Stdout}, nil
}
f, err := os.Create(filename)
return filename, f, err
}
// nopwritercloser wraps an io.Writer and provides a no-op Close() method.
type nopwritercloser struct {
io.Writer
}
func (nopwritercloser) Close() error { return nil }
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