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|
package command
import (
"bytes"
"errors"
"fmt"
"io"
"strings"
"text/tabwriter"
)
var ErrHelp = errors.New("help requested")
func (n *node) PrintHelp() { _ = n.writeHelp() }
func (n *node) writeHelp() error {
prefix := strings.Join(append(n.prefix, n.name), " ")
var buf strings.Builder
offset := 7 + len(prefix)
line := offset + 14
w := bytes.Repeat([]byte{' '}, offset+1)
w[0] = '\n'
for _, flag := range n.suffix {
line += len(flag) + 1
if line >= 80 {
line = offset + len(flag) + 1
buf.Write(w)
}
buf.WriteByte(' ')
buf.WriteString(flag)
}
if _, err := fmt.Fprintf(n.out,
"usage: %s [-h | --help]%s <command> [<args>]\n",
prefix, &buf,
); err != nil {
return err
}
if n.child != nil {
if _, err := fmt.Fprint(n.out, "\ncommands:\n"); err != nil {
return err
}
}
tw := tabwriter.NewWriter(n.out, 0, 1, 4, ' ', 0)
if err := n.child.writeCommands(tw); err != nil {
return err
}
if err := tw.Flush(); err != nil {
return err
}
_, err := n.out.Write([]byte{'\n'})
if err == nil {
err = ErrHelp
}
return err
}
func (n *node) writeCommands(w io.Writer) error {
if n == nil {
return nil
}
if n.usage != UsageInternal {
if _, err := fmt.Fprintf(w, "\t%s\t%s\n", n.name, n.usage); err != nil {
return err
}
}
return n.next.writeCommands(w)
}
|
