Hojun-Cho
2d99c39604
- appendList: one home for the List newline-join rule (was duplicated across accumulate and set) - fold the redundant Int64 getter into Int; drop the truthy helper for the shared boolWord vocabulary - add Opt.Metavar so help derives the value placeholder from data instead of branching on the option name (seed-time) No behavior change; --help output is byte-identical.
120 lines
2.9 KiB
Go
120 lines
2.9 KiB
Go
package cli
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import (
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"fmt"
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"io"
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"strings"
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)
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// Version is the program version, overridable at build time via -ldflags.
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var Version = "0.1.0"
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// PrintVersion writes the version banner.
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func PrintVersion(w io.Writer) {
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fmt.Fprintf(w, "got %s — a Rob-Pike-style command-line downloader in Go\n", Version)
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}
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// PrintHelp writes usage. A bare -h/--help (empty tag) shows only the Basic
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// group, keeping the default terse; --help=all shows every group and
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// --help=<group> (basic/http/bittorrent/advanced) filters to one.
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func PrintHelp(w io.Writer, tag string) {
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all := tag == "all"
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// Empty tag means a bare -h/--help: default to the Basic group only.
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bare := tag == ""
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want, filtered := tagByName(tag)
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if bare {
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want, filtered = Basic, true
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}
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if !all && !bare && !filtered {
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fmt.Fprintf(w, "got: unknown help tag %q (use all|basic|http|bittorrent|advanced)\n\n", tag)
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}
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fmt.Fprint(w, `Usage: got [OPTIONS] URI | magnet:... | file.torrent ...
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A multi-protocol download tool: segmented HTTP(S) and BitTorrent.
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`)
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for _, group := range []Tag{Basic, HTTP, BitTorrent, Advanced} {
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if filtered && !all && group != want {
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continue
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}
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fmt.Fprintf(w, "%s options:\n", title(group.String()))
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for i := range options {
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o := &options[i]
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if o.Tag != group {
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continue
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}
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fmt.Fprintf(w, " %s %s\n", flagLabel(o), o.Help)
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}
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fmt.Fprintln(w)
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}
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// Only the full listing (all groups) repeats the meta flags.
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if all || !filtered {
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fmt.Fprint(w, " -h, --help[=TAG] show help (TAG: all|basic|http|bittorrent|advanced)\n")
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fmt.Fprint(w, " -v, --version show version\n\n")
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}
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if bare {
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fmt.Fprint(w, "Showing basic options. Use --help=all for every option, or --help=advanced for advanced ones.\n")
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}
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}
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// title upper-cases the first letter of a single word.
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func title(s string) string {
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if s == "" {
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return s
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}
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return strings.ToUpper(s[:1]) + s[1:]
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}
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func tagByName(name string) (Tag, bool) {
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switch name {
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case "basic":
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return Basic, true
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case "http":
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return HTTP, true
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case "bittorrent", "bt":
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return BitTorrent, true
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case "advanced":
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return Advanced, true
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default:
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return Basic, false
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}
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}
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// flagLabel renders the "-x, --long=ARG" column for one option.
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func flagLabel(o *Opt) string {
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var b strings.Builder
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if o.Short != 0 {
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fmt.Fprintf(&b, "-%c, ", o.Short)
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} else {
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b.WriteString(" ")
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}
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b.WriteString("--" + o.Long)
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if m := metavar(o); m != "" {
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b.WriteString("=" + m)
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}
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return b.String()
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}
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// metavar is the placeholder shown after a value-taking flag, e.g. the "N" in
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// "--split=N". An explicit Opt.Metavar wins; otherwise it derives from the Kind.
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// Bool takes no value, so its metavar is empty and no "=ARG" is printed.
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func metavar(o *Opt) string {
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if o.Metavar != "" {
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return o.Metavar
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}
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switch o.Kind {
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case Bool:
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return ""
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case Size:
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return "SIZE"
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case Int:
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return "N"
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case Float:
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return "RATIO"
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case Enum:
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return strings.Join(o.Enum, "|")
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default:
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return "VAL"
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}
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}
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