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package flags
import (
"reflect"
"sort"
"strconv"
"strings"
)
// Command represents an application command. Commands can be added to the
// parser (which itself is a command) and are selected/executed when its name
// is specified on the command line. The Command type embeds a Group and
// therefore also carries a set of command specific options.
type Command struct {
// Embedded, see Group for more information
*Group
// The name by which the command can be invoked
Name string
// The active sub command (set by parsing) or nil
Active *Command
// Whether subcommands are optional
SubcommandsOptional bool
// Aliases for the command
Aliases []string
// Whether positional arguments are required
ArgsRequired bool
commands []*Command
hasBuiltinHelpGroup bool
args []*Arg
}
// Commander is an interface which can be implemented by any command added in
// the options. When implemented, the Execute method will be called for the last
// specified (sub)command providing the remaining command line arguments.
type Commander interface {
// Execute will be called for the last active (sub)command. The
// args argument contains the remaining command line arguments. The
// error that Execute returns will be eventually passed out of the
// Parse method of the Parser.
Execute(args []string) error
}
// Usage is an interface which can be implemented to show a custom usage string
// in the help message shown for a command.
type Usage interface {
// Usage is called for commands to allow customized printing of command
// usage in the generated help message.
Usage() string
}
type lookup struct {
shortNames map[string]*Option
longNames map[string]*Option
commands map[string]*Command
}
// AddCommand adds a new command to the parser with the given name and data. The
// data needs to be a pointer to a struct from which the fields indicate which
// options are in the command. The provided data can implement the Command and
// Usage interfaces.
func (c *Command) AddCommand(command string, shortDescription string, longDescription string, data interface{}) (*Command, error) {
cmd := newCommand(command, shortDescription, longDescription, data)
cmd.parent = c
if err := cmd.scan(); err != nil {
return nil, err
}
c.commands = append(c.commands, cmd)
return cmd, nil
}
// AddGroup adds a new group to the command with the given name and data. The
// data needs to be a pointer to a struct from which the fields indicate which
// options are in the group.
func (c *Command) AddGroup(shortDescription string, longDescription string, data interface{}) (*Group, error) {
group := newGroup(shortDescription, longDescription, data)
group.parent = c
if err := group.scanType(c.scanSubcommandHandler(group)); err != nil {
return nil, err
}
c.groups = append(c.groups, group)
return group, nil
}
// Commands returns a list of subcommands of this command.
func (c *Command) Commands() []*Command {
return c.commands
}
// Find locates the subcommand with the given name and returns it. If no such
// command can be found Find will return nil.
func (c *Command) Find(name string) *Command {
for _, cc := range c.commands {
if cc.match(name) {
return cc
}
}
return nil
}
// FindOptionByLongName finds an option that is part of the command, or any of
// its parent commands, by matching its long name (including the option
// namespace).
func (c *Command) FindOptionByLongName(longName string) (option *Option) {
for option == nil && c != nil {
option = c.Group.FindOptionByLongName(longName)
c, _ = c.parent.(*Command)
}
return option
}
// FindOptionByShortName finds an option that is part of the command, or any of
// its parent commands, by matching its long name (including the option
// namespace).
func (c *Command) FindOptionByShortName(shortName rune) (option *Option) {
for option == nil && c != nil {
option = c.Group.FindOptionByShortName(shortName)
c, _ = c.parent.(*Command)
}
return option
}
// Args returns a list of positional arguments associated with this command.
func (c *Command) Args() []*Arg {
ret := make([]*Arg, len(c.args))
copy(ret, c.args)
return ret
}
func newCommand(name string, shortDescription string, longDescription string, data interface{}) *Command {
return &Command{
Group: newGroup(shortDescription, longDescription, data),
Name: name,
}
}
func (c *Command) scanSubcommandHandler(parentg *Group) scanHandler {
f := func(realval reflect.Value, sfield *reflect.StructField) (bool, error) {
mtag := newMultiTag(string(sfield.Tag))
if err := mtag.Parse(); err != nil {
return true, err
}
positional := mtag.Get("positional-args")
if len(positional) != 0 {
stype := realval.Type()
for i := 0; i < stype.NumField(); i++ {
field := stype.Field(i)
m := newMultiTag((string(field.Tag)))
if err := m.Parse(); err != nil {
return true, err
}
name := m.Get("positional-arg-name")
if len(name) == 0 {
name = field.Name
}
required := -1
requiredMaximum := -1
sreq := m.Get("required")
if sreq != "" {
required = 1
rng := strings.SplitN(sreq, "-", 2)
if len(rng) > 1 {
if preq, err := strconv.ParseInt(rng[0], 10, 32); err == nil {
required = int(preq)
}
if preq, err := strconv.ParseInt(rng[1], 10, 32); err == nil {
requiredMaximum = int(preq)
}
} else {
if preq, err := strconv.ParseInt(sreq, 10, 32); err == nil {
required = int(preq)
}
}
}
arg := &Arg{
Name: name,
Description: m.Get("description"),
Required: required,
RequiredMaximum: requiredMaximum,
value: realval.Field(i),
tag: m,
}
c.args = append(c.args, arg)
if len(mtag.Get("required")) != 0 {
c.ArgsRequired = true
}
}
return true, nil
}
subcommand := mtag.Get("command")
if len(subcommand) != 0 {
var ptrval reflect.Value
if realval.Kind() == reflect.Ptr {
ptrval = realval
if ptrval.IsNil() {
ptrval.Set(reflect.New(ptrval.Type().Elem()))
}
} else {
ptrval = realval.Addr()
}
shortDescription := mtag.Get("description")
longDescription := mtag.Get("long-description")
subcommandsOptional := mtag.Get("subcommands-optional")
aliases := mtag.GetMany("alias")
subc, err := c.AddCommand(subcommand, shortDescription, longDescription, ptrval.Interface())
if err != nil {
return true, err
}
subc.Hidden = mtag.Get("hidden") != ""
if len(subcommandsOptional) > 0 {
subc.SubcommandsOptional = true
}
if len(aliases) > 0 {
subc.Aliases = aliases
}
return true, nil
}
return parentg.scanSubGroupHandler(realval, sfield)
}
return f
}
func (c *Command) scan() error {
return c.scanType(c.scanSubcommandHandler(c.Group))
}
func (c *Command) eachOption(f func(*Command, *Group, *Option)) {
c.eachCommand(func(c *Command) {
c.eachGroup(func(g *Group) {
for _, option := range g.options {
f(c, g, option)
}
})
}, true)
}
func (c *Command) eachCommand(f func(*Command), recurse bool) {
f(c)
for _, cc := range c.commands {
if recurse {
cc.eachCommand(f, true)
} else {
f(cc)
}
}
}
func (c *Command) eachActiveGroup(f func(cc *Command, g *Group)) {
c.eachGroup(func(g *Group) {
f(c, g)
})
if c.Active != nil {
c.Active.eachActiveGroup(f)
}
}
func (c *Command) addHelpGroups(showHelp func() error) {
if !c.hasBuiltinHelpGroup {
c.addHelpGroup(showHelp)
c.hasBuiltinHelpGroup = true
}
for _, cc := range c.commands {
cc.addHelpGroups(showHelp)
}
}
func (c *Command) makeLookup() lookup {
ret := lookup{
shortNames: make(map[string]*Option),
longNames: make(map[string]*Option),
commands: make(map[string]*Command),
}
parent := c.parent
var parents []*Command
for parent != nil {
if cmd, ok := parent.(*Command); ok {
parents = append(parents, cmd)
parent = cmd.parent
} else {
parent = nil
}
}
for i := len(parents) - 1; i >= 0; i-- {
parents[i].fillLookup(&ret, true)
}
c.fillLookup(&ret, false)
return ret
}
func (c *Command) fillLookup(ret *lookup, onlyOptions bool) {
c.eachGroup(func(g *Group) {
for _, option := range g.options {
if option.ShortName != 0 {
ret.shortNames[string(option.ShortName)] = option
}
if len(option.LongName) > 0 {
ret.longNames[option.LongNameWithNamespace()] = option
}
}
})
if onlyOptions {
return
}
for _, subcommand := range c.commands {
ret.commands[subcommand.Name] = subcommand
for _, a := range subcommand.Aliases {
ret.commands[a] = subcommand
}
}
}
func (c *Command) groupByName(name string) *Group {
if grp := c.Group.groupByName(name); grp != nil {
return grp
}
for _, subc := range c.commands {
prefix := subc.Name + "."
if strings.HasPrefix(name, prefix) {
if grp := subc.groupByName(name[len(prefix):]); grp != nil {
return grp
}
} else if name == subc.Name {
return subc.Group
}
}
return nil
}
type commandList []*Command
func (c commandList) Less(i, j int) bool {
return c[i].Name < c[j].Name
}
func (c commandList) Len() int {
return len(c)
}
func (c commandList) Swap(i, j int) {
c[i], c[j] = c[j], c[i]
}
func (c *Command) sortedVisibleCommands() []*Command {
ret := commandList(c.visibleCommands())
sort.Sort(ret)
return []*Command(ret)
}
func (c *Command) visibleCommands() []*Command {
ret := make([]*Command, 0, len(c.commands))
for _, cmd := range c.commands {
if !cmd.Hidden {
ret = append(ret, cmd)
}
}
return ret
}
func (c *Command) match(name string) bool {
if c.Name == name {
return true
}
for _, v := range c.Aliases {
if v == name {
return true
}
}
return false
}
func (c *Command) hasHelpOptions() bool {
ret := false
c.eachGroup(func(g *Group) {
if g.isBuiltinHelp {
return
}
for _, opt := range g.options {
if opt.showInHelp() {
ret = true
}
}
})
return ret
}
func (c *Command) fillParseState(s *parseState) {
s.positional = make([]*Arg, len(c.args))
copy(s.positional, c.args)
s.lookup = c.makeLookup()
s.command = c
}
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