/
command.go
116 lines (100 loc) · 2.82 KB
/
command.go
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package imagectl
import (
"fmt"
"os"
"strings"
)
type Command struct {
Shortcuts []string
Name string
ReqArgs []string
OptArgs []string
Description string
Executor func(args []string) int
}
func (c Command) ArgsDescription() string {
desc := strings.Join(c.ReqArgs, " ")
if len(c.OptArgs) > 0 {
desc = desc + " [" + strings.Join(c.OptArgs, "] [") + "]"
}
return desc
}
func (c Command) CheckArgs(args []string) bool {
at_least := len(c.ReqArgs)
at_most := len(c.ReqArgs) + len(c.OptArgs)
last_arg := ""
if len(c.OptArgs) > 0 {
last_arg = c.OptArgs[len(c.OptArgs)-1]
} else if len(c.ReqArgs) > 0 {
last_arg = c.ReqArgs[len(c.ReqArgs)-1]
}
if len(args) < at_least {
if at_least == 1 {
fmt.Fprintf(os.Stderr, "%v: \"%v\" requires at least 1 argument.\n\n", os.Args[0], c.Name)
} else {
fmt.Fprintf(os.Stderr, "%v: \"%v\" requires at least %v arguments.\n\n", os.Args[0], c.Name, at_least)
}
fmt.Fprintf(os.Stderr, "Usage: %v %v %v\n\n", os.Args[0], c.Name, c.ArgsDescription())
fmt.Fprint(os.Stderr, c.Description + "\n")
return false
}
if len(args) > at_most && !strings.HasSuffix(last_arg, "...") {
if at_most == 1 {
fmt.Fprintf(os.Stderr, "%v: \"%v\" takes at most 1 argument.\n\n", os.Args[0], c.Name)
} else {
fmt.Fprintf(os.Stderr, "%v: \"%v\" takes at most %v arguments.\n\n", os.Args[0], c.Name, at_most)
}
fmt.Fprintf(os.Stderr, "Usage: %v %v %v\n\n", os.Args[0], c.Name, c.ArgsDescription())
fmt.Fprint(os.Stderr, c.Description + "\n")
return false
}
return true
}
func (c Command) Run(args []string) int {
if !c.CheckArgs(args) {
return 1
}
return c.Executor(args)
}
type CommandGroup struct {
Name string
Commands []Command
}
func PrintHelp(desc string, commandGroups []CommandGroup) {
fmt.Printf("Usage: %v COMMAND [arg...]\n", os.Args[0])
fmt.Printf(" %v [ -h | --help | -v | --version ]\n", os.Args[0])
fmt.Println()
fmt.Println(desc)
for _, group := range commandGroups {
fmt.Println()
fmt.Println(group.Name + " Commands:")
for _, c := range group.Commands {
shortcut := ""
if len(c.Shortcuts) > 0 {
shortcut = c.Shortcuts[0] + ","
}
fmt.Printf(" %5v %-27v %v\n", shortcut, c.Name + " " + c.ArgsDescription(), c.Description)
}
}
}
func PrintInvalidCommand(name string) {
fmt.Fprintf(os.Stderr, "%v: \"%v\" is not a valid command.\n", os.Args[0], name)
fmt.Fprintf(os.Stderr, "See '%v --help'.\n", os.Args[0])
}
func RunCommand(args []string, commandGroups []CommandGroup) int {
var commandMap = map[string]Command{}
for _, group := range commandGroups {
for _, cmd := range group.Commands {
commandMap[cmd.Name] = cmd
for _, shortcut := range cmd.Shortcuts {
commandMap[shortcut] = cmd
}
}
}
cmd, ok := commandMap[args[0]]
if !ok {
PrintInvalidCommand(args[0])
return 1
}
return cmd.Run(args[1:])
}