syncthing/vendor/github.com/AudriusButkevicius/cli/command.go

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package cli
import (
"fmt"
"io/ioutil"
"strings"
)
// Command is a subcommand for a cli.App.
type Command struct {
// The name of the command
Name string
// short name of the command. Typically one character
ShortName string
// A short description of the usage of this command
Usage string
// A longer explanation of how the command works
Description string
// The function to call when checking for bash command completions
BashComplete func(context *Context)
// An action to execute before any sub-subcommands are run, but after the context is ready
// If a non-nil error is returned, no sub-subcommands are run
Before func(context *Context) error
// The function to call when this command is invoked
Action func(context *Context)
// List of child commands
Subcommands []Command
// List of flags to parse
Flags []Flag
// Treat all flags as normal arguments if true
SkipFlagParsing bool
// Boolean to hide built-in help command
HideHelp bool
// Command argument requirements
Requires *Requires
}
// Invokes the command given the context, parses ctx.Args() to generate command-specific flags
func (c Command) Run(ctx *Context) error {
if len(c.Subcommands) > 0 || c.Before != nil {
return c.startApp(ctx)
}
if !c.HideHelp {
// append help to flags
c.Flags = append(
c.Flags,
HelpFlag,
)
}
if ctx.App.EnableBashCompletion {
c.Flags = append(c.Flags, BashCompletionFlag)
}
set := flagSet(c.Name, c.Flags)
set.SetOutput(ioutil.Discard)
firstFlagIndex := -1
for index, arg := range ctx.Args() {
if strings.HasPrefix(arg, "-") {
firstFlagIndex = index
break
}
}
var err error
if firstFlagIndex > -1 && !c.SkipFlagParsing {
args := ctx.Args()
regularArgs := args[1:firstFlagIndex]
flagArgs := args[firstFlagIndex:]
err = set.Parse(append(flagArgs, regularArgs...))
} else {
err = set.Parse(ctx.Args().Tail())
}
if err != nil {
fmt.Printf("Incorrect Usage.\n\n")
ShowCommandHelp(ctx, c.Name)
fmt.Println("")
return err
}
nerr := normalizeFlags(c.Flags, set)
if nerr != nil {
fmt.Println(nerr)
fmt.Println("")
ShowCommandHelp(ctx, c.Name)
fmt.Println("")
return nerr
}
context := NewContext(ctx.App, set, ctx.globalSet)
if checkCommandCompletions(context, c.Name) {
return nil
}
if checkCommandHelp(context, c.Name) {
return nil
}
if err := context.Satisfies(c.Requires); err != nil {
return err
}
context.Command = c
c.Action(context)
return nil
}
// Returns true if Command.Name or Command.ShortName matches given name
func (c Command) HasName(name string) bool {
return c.Name == name || c.ShortName == name
}
func (c Command) startApp(ctx *Context) error {
app := NewApp()
// set the name and usage
app.Name = fmt.Sprintf("%s %s", ctx.App.Name, c.Name)
if c.Description != "" {
app.Usage = c.Description
} else {
app.Usage = c.Usage
}
// set the flags and commands
app.Commands = c.Subcommands
app.Flags = c.Flags
app.HideHelp = c.HideHelp
// bash completion
app.EnableBashCompletion = ctx.App.EnableBashCompletion
if c.BashComplete != nil {
app.BashComplete = c.BashComplete
}
// set the actions
app.Before = c.Before
if c.Action != nil {
app.Action = c.Action
} else {
app.Action = helpSubcommand.Action
}
return app.RunAsSubcommand(ctx)
}