initial commit of cobra w/test suite
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spf13
304
cobra.go
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304
cobra.go
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// Copyright © 2013 Steve Francia <spf@spf13.com>.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Commands similar to git, go tools and other modern CLI tools
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// inspired by go, go-Commander, gh and subcommand
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package cobra
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import (
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"bytes"
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"fmt"
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flag "github.com/ogier/pflag"
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"os"
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"strings"
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)
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var _ = flag.ContinueOnError
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type Flag interface {
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Args() []string
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}
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type Flags interface {
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Lookup(string) *Flag
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VisitAll(fn func(*Flag))
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Parse(arguments []string) error
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}
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// A Commander holds the configuration for the command line tool.
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type Commander struct {
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// A Commander is also a Command for top level and global help & flags
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Command
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//ExitOnError, ContinueOnError or PanicOnError
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behavior flag.ErrorHandling
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args []string
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}
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func NewCommander() (c *Commander) {
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c = new(Commander)
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return
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}
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func (c *Commander) setFlagBehavior(b flag.ErrorHandling) error {
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if b == flag.ExitOnError || b == flag.ContinueOnError || b == flag.PanicOnError {
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c.behavior = b
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return nil
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}
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return fmt.Errorf("%v is not a valid behavior", b)
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}
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func (c *Commander) SetName(name string) {
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c.name = name
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}
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func (c *Commander) SetArgs(a []string) {
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c.args = a
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}
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func (c *Commander) Execute() {
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if len(c.args) == 0 {
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c.execute(os.Args[1:])
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} else {
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c.execute(c.args)
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}
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}
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// Command is just that, a command for your application.
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// eg. 'go run' ... 'run' is the command. Cobra requires
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// you to define the usage and description as part of your command
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// definition to ensure usability.
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type Command struct {
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// Name is the command name, usually the executable's name.
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name string
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// The one-line usage message.
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Use string
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// The short description shown in the 'help' output.
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Short string
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// The long message shown in the 'help <this-command>' output.
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Long string
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// Set of flags specific to this command.
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flags *flag.FlagSet
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// Set of flags children commands will inherit
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pflags *flag.FlagSet
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// Run runs the command.
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// The args are the arguments after the command name.
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Run func(cmd *Command, args []string)
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// Commands is the list of commands supported by this Commander program.
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commands []*Command
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// Parent Command for this command
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parent *Command
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// Commander
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//cmdr *Commander
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flagErrorBuf *bytes.Buffer
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}
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// find the target command given the args and command tree
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func (c *Command) Find(args []string) (cmd *Command, a []string, err error) {
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if c == nil {
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return nil, nil, fmt.Errorf("Called find() on a nil Command")
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}
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validSubCommand := false
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if len(args) > 1 && c.HasSubCommands() {
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for _, cmd := range c.commands {
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if cmd.Name() == args[0] {
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validSubCommand = true
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return cmd.Find(args[1:])
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}
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}
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}
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if !validSubCommand && c.Runnable() {
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return c, args, nil
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}
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return nil, nil, nil
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}
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// execute the command determined by args and the command tree
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func (c *Command) execute(args []string) (err error) {
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err = fmt.Errorf("unknown subcommand %q\nRun 'help' for usage.\n", args[0])
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if c == nil {
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return fmt.Errorf("Called Execute() on a nil Command")
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}
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cmd, a, e := c.Find(args)
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if e == nil {
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cmd.Flags().Parse(a)
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argWoFlags := cmd.Flags().Args()
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cmd.Run(cmd, argWoFlags)
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return nil
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}
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err = e
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return err
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}
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// Add one or many commands as children of this
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func (c *Command) AddCommand(cmds ...*Command) {
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for i, x := range cmds {
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cmds[i].parent = c
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c.commands = append(c.commands, x)
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}
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}
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// The full usage for a given command (including parents)
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func (c *Command) Usage(depth ...int) string {
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i := 0
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if len(depth) > 0 {
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i = depth[0]
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}
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if c.HasParent() {
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return c.parent.Usage(i+1) + " " + c.Use
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} else if i > 0 {
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return c.Name()
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} else {
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return c.Use
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}
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}
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// Usage prints the usage details to the standard output.
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func (c *Command) PrintUsage() {
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if c.Runnable() {
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fmt.Printf("usage: %s\n\n", c.Usage())
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}
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fmt.Println(strings.Trim(c.Long, "\n"))
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}
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// Name returns the command's name: the first word in the use line.
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func (c *Command) Name() string {
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if c.name != "" {
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return c.name
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}
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name := c.Use
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i := strings.Index(name, " ")
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if i >= 0 {
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name = name[:i]
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}
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return name
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}
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// Determine if the command is itself runnable
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func (c *Command) Runnable() bool {
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return c.Run != nil
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}
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// Determine if the command has children commands
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func (c *Command) HasSubCommands() bool {
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return len(c.commands) > 0
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}
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// Determine if the command has children commands
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func (c *Command) HasParent() bool {
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return c.parent != nil
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}
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// Get the Commands FlagSet
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func (c *Command) Flags() *flag.FlagSet {
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if c.flags == nil {
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c.flags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
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c.flags.SetOutput(c.flagErrorBuf)
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}
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return c.flags
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}
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// Get the Commands Persistent FlagSet
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func (c *Command) PersistentFlags() *flag.FlagSet {
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if c.pflags == nil {
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c.pflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
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c.pflags.SetOutput(c.flagErrorBuf)
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}
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return c.flags
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}
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// Intended for use in testing
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func (c *Command) ResetFlags() {
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c.flags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
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c.flags.SetOutput(c.flagErrorBuf)
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c.pflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
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c.pflags.SetOutput(c.flagErrorBuf)
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}
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func (c *Command) HasFlags() bool {
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return hasFlags(c.flags)
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}
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func (c *Command) HasPersistentFlags() bool {
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return hasFlags(c.pflags)
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}
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// Is this set of flags not empty
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func hasFlags(f *flag.FlagSet) bool {
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if f == nil {
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return false
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}
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if f.NFlag() != 0 {
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return true
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}
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return false
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}
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// Climbs up the command tree looking for matching flag
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func (c *Command) Flag(name string) (flag *flag.Flag) {
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flag = c.Flags().Lookup(name)
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if flag == nil {
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flag = c.persistentFlag(name)
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}
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return
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}
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// recursively find matching persistent flag
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func (c *Command) persistentFlag(name string) (flag *flag.Flag) {
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if c.HasPersistentFlags() {
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flag = c.PersistentFlags().Lookup(name)
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}
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if flag == nil && c.HasParent() {
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flag = c.parent.persistentFlag(name)
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}
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return
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}
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// Parses persistent flag tree & local flags
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func (c *Command) ParseFlags(args []string) (err error) {
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err = c.ParsePersistentFlags(args)
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if err != nil {
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return err
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}
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err = c.Flags().Parse(args)
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if err != nil {
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return err
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}
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return nil
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}
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// Climbs up the command tree parsing flags from top to bottom
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func (c *Command) ParsePersistentFlags(args []string) (err error) {
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if !c.HasParent() || c.parent.PersistentFlags().Parsed() {
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err = c.PersistentFlags().Parse(args)
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if err != nil {
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return err
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}
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} else {
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err = c.parent.ParsePersistentFlags(args)
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if err != nil {
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return err
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}
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}
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return nil
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}
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