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/
help.go
144 lines (122 loc) · 2.69 KB
/
help.go
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package main
import (
"bytes"
"flag"
"fmt"
"os"
"text/template"
)
var helpCmd = &Command{
Name: "help",
Usage: "[COMMAND]",
Summary: "Print command usage and options.",
Help: `godm is a simple general-purpose document management system.
General Usage:
godm [OPTION] COMMAND [COMMAND OPTION]`,
}
func helpFunc(db *Db, cmd *Command, args []string) error {
switch {
case cmd == nil, cmd == helpCmd && len(args) != 1:
// no comand, just help command, or extra junk
return printGeneralHelp()
case cmd == helpCmd:
// help command with subcommand
if subcmd := findCommand(args[0]); subcmd != nil {
return printCommandHelp(subcmd)
} else {
// unknown subcommand
fmt.Errorf("unknown subcommand")
return printGeneralHelp()
}
}
// shouldn't get here
fmt.Errorf("unhandled case in helpFunc switch")
return printGeneralHelp()
}
func printGeneralHelp() error {
tmpl, err := template.New("appHelp").Funcs(funcMap).Parse(generalHelpTemplate)
if err != nil {
return err
}
err = tmpl.Execute(os.Stdout, commands)
if err != nil {
return err
}
return nil
}
func printCommandHelp(cmd *Command) error {
tmpl, err := template.New("comandHelp").Funcs(funcMap).Parse(commandHelpTemplate)
if err != nil {
return err
}
err = tmpl.Execute(os.Stdout, cmd)
if err != nil {
return err
}
return nil
}
func init() {
helpCmd.Function = helpFunc
}
var funcMap = template.FuncMap{
"appFlags": func() string {
var buf bytes.Buffer
flag.VisitAll(func(f *flag.Flag) {
if err := helpTemplates.ExecuteTemplate(&buf, "optionHelp", f); err != nil {
panic(err)
}
})
return buf.String()
},
"cmdFlags": func(cmdName string) string {
var buf bytes.Buffer
if cmd := findCommand(cmdName); cmd != nil {
cmd.Flag.VisitAll(func(f *flag.Flag) {
if err := helpTemplates.ExecuteTemplate(&buf, "optionHelp", f); err != nil {
panic(err)
}
})
}
return buf.String()
},
}
func renderTemplate(tmpl *template.Template, name string, data interface{}) string {
var buf bytes.Buffer
if err := tmpl.ExecuteTemplate(&buf, name, data); err != nil {
panic(err)
}
return buf.String()
}
var helpTemplates template.Template
func init() {
helpTemplates.New("optionHelp").Parse(optionHelpTemplate)
}
var optionHelpTemplate = `
-{{.Name}}=[{{.DefValue}}]
{{.Usage}}`
var generalHelpTemplate = `
godm version 0.1
SYNOPSIS
godm is a simple general-purpose document management system.
USAGE
godm [OPTION] COMMAND [COMMAND OPTION]
OPTIONS
{{appFlags}}
COMMANDS
{{range .}}
{{.Name}} {{.Usage}}
{{.Summary}}
{{end}}
`
var commandHelpTemplate = `
godm version 0.1
{{.Name}}
SYNOPSIS
{{.Summary}}
USAGE
{{.Name}} [OPTION]
DESCRIPTION
{{.Help}}
OPTIONS
{{cmdFlags .Name}}
`