Matteo Scandolo | a6a3aee | 2019-11-26 13:30:14 -0700 | [diff] [blame] | 1 | package flags |
| 2 | |
| 3 | import ( |
| 4 | "reflect" |
| 5 | "sort" |
| 6 | "strconv" |
| 7 | "strings" |
| 8 | ) |
| 9 | |
| 10 | // Command represents an application command. Commands can be added to the |
| 11 | // parser (which itself is a command) and are selected/executed when its name |
| 12 | // is specified on the command line. The Command type embeds a Group and |
| 13 | // therefore also carries a set of command specific options. |
| 14 | type Command struct { |
| 15 | // Embedded, see Group for more information |
| 16 | *Group |
| 17 | |
| 18 | // The name by which the command can be invoked |
| 19 | Name string |
| 20 | |
| 21 | // The active sub command (set by parsing) or nil |
| 22 | Active *Command |
| 23 | |
| 24 | // Whether subcommands are optional |
| 25 | SubcommandsOptional bool |
| 26 | |
| 27 | // Aliases for the command |
| 28 | Aliases []string |
| 29 | |
| 30 | // Whether positional arguments are required |
| 31 | ArgsRequired bool |
| 32 | |
| 33 | commands []*Command |
| 34 | hasBuiltinHelpGroup bool |
| 35 | args []*Arg |
| 36 | } |
| 37 | |
| 38 | // Commander is an interface which can be implemented by any command added in |
| 39 | // the options. When implemented, the Execute method will be called for the last |
| 40 | // specified (sub)command providing the remaining command line arguments. |
| 41 | type Commander interface { |
| 42 | // Execute will be called for the last active (sub)command. The |
| 43 | // args argument contains the remaining command line arguments. The |
| 44 | // error that Execute returns will be eventually passed out of the |
| 45 | // Parse method of the Parser. |
| 46 | Execute(args []string) error |
| 47 | } |
| 48 | |
| 49 | // Usage is an interface which can be implemented to show a custom usage string |
| 50 | // in the help message shown for a command. |
| 51 | type Usage interface { |
| 52 | // Usage is called for commands to allow customized printing of command |
| 53 | // usage in the generated help message. |
| 54 | Usage() string |
| 55 | } |
| 56 | |
| 57 | type lookup struct { |
| 58 | shortNames map[string]*Option |
| 59 | longNames map[string]*Option |
| 60 | |
| 61 | commands map[string]*Command |
| 62 | } |
| 63 | |
| 64 | // AddCommand adds a new command to the parser with the given name and data. The |
| 65 | // data needs to be a pointer to a struct from which the fields indicate which |
| 66 | // options are in the command. The provided data can implement the Command and |
| 67 | // Usage interfaces. |
| 68 | func (c *Command) AddCommand(command string, shortDescription string, longDescription string, data interface{}) (*Command, error) { |
| 69 | cmd := newCommand(command, shortDescription, longDescription, data) |
| 70 | |
| 71 | cmd.parent = c |
| 72 | |
| 73 | if err := cmd.scan(); err != nil { |
| 74 | return nil, err |
| 75 | } |
| 76 | |
| 77 | c.commands = append(c.commands, cmd) |
| 78 | return cmd, nil |
| 79 | } |
| 80 | |
| 81 | // AddGroup adds a new group to the command with the given name and data. The |
| 82 | // data needs to be a pointer to a struct from which the fields indicate which |
| 83 | // options are in the group. |
| 84 | func (c *Command) AddGroup(shortDescription string, longDescription string, data interface{}) (*Group, error) { |
| 85 | group := newGroup(shortDescription, longDescription, data) |
| 86 | |
| 87 | group.parent = c |
| 88 | |
| 89 | if err := group.scanType(c.scanSubcommandHandler(group)); err != nil { |
| 90 | return nil, err |
| 91 | } |
| 92 | |
| 93 | c.groups = append(c.groups, group) |
| 94 | return group, nil |
| 95 | } |
| 96 | |
| 97 | // Commands returns a list of subcommands of this command. |
| 98 | func (c *Command) Commands() []*Command { |
| 99 | return c.commands |
| 100 | } |
| 101 | |
| 102 | // Find locates the subcommand with the given name and returns it. If no such |
| 103 | // command can be found Find will return nil. |
| 104 | func (c *Command) Find(name string) *Command { |
| 105 | for _, cc := range c.commands { |
| 106 | if cc.match(name) { |
| 107 | return cc |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | return nil |
| 112 | } |
| 113 | |
| 114 | // FindOptionByLongName finds an option that is part of the command, or any of |
| 115 | // its parent commands, by matching its long name (including the option |
| 116 | // namespace). |
| 117 | func (c *Command) FindOptionByLongName(longName string) (option *Option) { |
| 118 | for option == nil && c != nil { |
| 119 | option = c.Group.FindOptionByLongName(longName) |
| 120 | |
| 121 | c, _ = c.parent.(*Command) |
| 122 | } |
| 123 | |
| 124 | return option |
| 125 | } |
| 126 | |
| 127 | // FindOptionByShortName finds an option that is part of the command, or any of |
| 128 | // its parent commands, by matching its long name (including the option |
| 129 | // namespace). |
| 130 | func (c *Command) FindOptionByShortName(shortName rune) (option *Option) { |
| 131 | for option == nil && c != nil { |
| 132 | option = c.Group.FindOptionByShortName(shortName) |
| 133 | |
| 134 | c, _ = c.parent.(*Command) |
| 135 | } |
| 136 | |
| 137 | return option |
| 138 | } |
| 139 | |
| 140 | // Args returns a list of positional arguments associated with this command. |
| 141 | func (c *Command) Args() []*Arg { |
| 142 | ret := make([]*Arg, len(c.args)) |
| 143 | copy(ret, c.args) |
| 144 | |
| 145 | return ret |
| 146 | } |
| 147 | |
| 148 | func newCommand(name string, shortDescription string, longDescription string, data interface{}) *Command { |
| 149 | return &Command{ |
| 150 | Group: newGroup(shortDescription, longDescription, data), |
| 151 | Name: name, |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | func (c *Command) scanSubcommandHandler(parentg *Group) scanHandler { |
| 156 | f := func(realval reflect.Value, sfield *reflect.StructField) (bool, error) { |
| 157 | mtag := newMultiTag(string(sfield.Tag)) |
| 158 | |
| 159 | if err := mtag.Parse(); err != nil { |
| 160 | return true, err |
| 161 | } |
| 162 | |
| 163 | positional := mtag.Get("positional-args") |
| 164 | |
| 165 | if len(positional) != 0 { |
| 166 | stype := realval.Type() |
| 167 | |
| 168 | for i := 0; i < stype.NumField(); i++ { |
| 169 | field := stype.Field(i) |
| 170 | |
| 171 | m := newMultiTag((string(field.Tag))) |
| 172 | |
| 173 | if err := m.Parse(); err != nil { |
| 174 | return true, err |
| 175 | } |
| 176 | |
| 177 | name := m.Get("positional-arg-name") |
| 178 | |
| 179 | if len(name) == 0 { |
| 180 | name = field.Name |
| 181 | } |
| 182 | |
| 183 | required := -1 |
| 184 | requiredMaximum := -1 |
| 185 | |
| 186 | sreq := m.Get("required") |
| 187 | |
| 188 | if sreq != "" { |
| 189 | required = 1 |
| 190 | |
| 191 | rng := strings.SplitN(sreq, "-", 2) |
| 192 | |
| 193 | if len(rng) > 1 { |
| 194 | if preq, err := strconv.ParseInt(rng[0], 10, 32); err == nil { |
| 195 | required = int(preq) |
| 196 | } |
| 197 | |
| 198 | if preq, err := strconv.ParseInt(rng[1], 10, 32); err == nil { |
| 199 | requiredMaximum = int(preq) |
| 200 | } |
| 201 | } else { |
| 202 | if preq, err := strconv.ParseInt(sreq, 10, 32); err == nil { |
| 203 | required = int(preq) |
| 204 | } |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | arg := &Arg{ |
| 209 | Name: name, |
| 210 | Description: m.Get("description"), |
| 211 | Required: required, |
| 212 | RequiredMaximum: requiredMaximum, |
| 213 | |
| 214 | value: realval.Field(i), |
| 215 | tag: m, |
| 216 | } |
| 217 | |
| 218 | c.args = append(c.args, arg) |
| 219 | |
| 220 | if len(mtag.Get("required")) != 0 { |
| 221 | c.ArgsRequired = true |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | return true, nil |
| 226 | } |
| 227 | |
| 228 | subcommand := mtag.Get("command") |
| 229 | |
| 230 | if len(subcommand) != 0 { |
| 231 | var ptrval reflect.Value |
| 232 | |
| 233 | if realval.Kind() == reflect.Ptr { |
| 234 | ptrval = realval |
| 235 | |
| 236 | if ptrval.IsNil() { |
| 237 | ptrval.Set(reflect.New(ptrval.Type().Elem())) |
| 238 | } |
| 239 | } else { |
| 240 | ptrval = realval.Addr() |
| 241 | } |
| 242 | |
| 243 | shortDescription := mtag.Get("description") |
| 244 | longDescription := mtag.Get("long-description") |
| 245 | subcommandsOptional := mtag.Get("subcommands-optional") |
| 246 | aliases := mtag.GetMany("alias") |
| 247 | |
| 248 | subc, err := c.AddCommand(subcommand, shortDescription, longDescription, ptrval.Interface()) |
| 249 | |
| 250 | if err != nil { |
| 251 | return true, err |
| 252 | } |
| 253 | |
| 254 | subc.Hidden = mtag.Get("hidden") != "" |
| 255 | |
| 256 | if len(subcommandsOptional) > 0 { |
| 257 | subc.SubcommandsOptional = true |
| 258 | } |
| 259 | |
| 260 | if len(aliases) > 0 { |
| 261 | subc.Aliases = aliases |
| 262 | } |
| 263 | |
| 264 | return true, nil |
| 265 | } |
| 266 | |
| 267 | return parentg.scanSubGroupHandler(realval, sfield) |
| 268 | } |
| 269 | |
| 270 | return f |
| 271 | } |
| 272 | |
| 273 | func (c *Command) scan() error { |
| 274 | return c.scanType(c.scanSubcommandHandler(c.Group)) |
| 275 | } |
| 276 | |
| 277 | func (c *Command) eachOption(f func(*Command, *Group, *Option)) { |
| 278 | c.eachCommand(func(c *Command) { |
| 279 | c.eachGroup(func(g *Group) { |
| 280 | for _, option := range g.options { |
| 281 | f(c, g, option) |
| 282 | } |
| 283 | }) |
| 284 | }, true) |
| 285 | } |
| 286 | |
| 287 | func (c *Command) eachCommand(f func(*Command), recurse bool) { |
| 288 | f(c) |
| 289 | |
| 290 | for _, cc := range c.commands { |
| 291 | if recurse { |
| 292 | cc.eachCommand(f, true) |
| 293 | } else { |
| 294 | f(cc) |
| 295 | } |
| 296 | } |
| 297 | } |
| 298 | |
| 299 | func (c *Command) eachActiveGroup(f func(cc *Command, g *Group)) { |
| 300 | c.eachGroup(func(g *Group) { |
| 301 | f(c, g) |
| 302 | }) |
| 303 | |
| 304 | if c.Active != nil { |
| 305 | c.Active.eachActiveGroup(f) |
| 306 | } |
| 307 | } |
| 308 | |
| 309 | func (c *Command) addHelpGroups(showHelp func() error) { |
| 310 | if !c.hasBuiltinHelpGroup { |
| 311 | c.addHelpGroup(showHelp) |
| 312 | c.hasBuiltinHelpGroup = true |
| 313 | } |
| 314 | |
| 315 | for _, cc := range c.commands { |
| 316 | cc.addHelpGroups(showHelp) |
| 317 | } |
| 318 | } |
| 319 | |
| 320 | func (c *Command) makeLookup() lookup { |
| 321 | ret := lookup{ |
| 322 | shortNames: make(map[string]*Option), |
| 323 | longNames: make(map[string]*Option), |
| 324 | commands: make(map[string]*Command), |
| 325 | } |
| 326 | |
| 327 | parent := c.parent |
| 328 | |
| 329 | var parents []*Command |
| 330 | |
| 331 | for parent != nil { |
| 332 | if cmd, ok := parent.(*Command); ok { |
| 333 | parents = append(parents, cmd) |
| 334 | parent = cmd.parent |
| 335 | } else { |
| 336 | parent = nil |
| 337 | } |
| 338 | } |
| 339 | |
| 340 | for i := len(parents) - 1; i >= 0; i-- { |
| 341 | parents[i].fillLookup(&ret, true) |
| 342 | } |
| 343 | |
| 344 | c.fillLookup(&ret, false) |
| 345 | return ret |
| 346 | } |
| 347 | |
| 348 | func (c *Command) fillLookup(ret *lookup, onlyOptions bool) { |
| 349 | c.eachGroup(func(g *Group) { |
| 350 | for _, option := range g.options { |
| 351 | if option.ShortName != 0 { |
| 352 | ret.shortNames[string(option.ShortName)] = option |
| 353 | } |
| 354 | |
| 355 | if len(option.LongName) > 0 { |
| 356 | ret.longNames[option.LongNameWithNamespace()] = option |
| 357 | } |
| 358 | } |
| 359 | }) |
| 360 | |
| 361 | if onlyOptions { |
| 362 | return |
| 363 | } |
| 364 | |
| 365 | for _, subcommand := range c.commands { |
| 366 | ret.commands[subcommand.Name] = subcommand |
| 367 | |
| 368 | for _, a := range subcommand.Aliases { |
| 369 | ret.commands[a] = subcommand |
| 370 | } |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | func (c *Command) groupByName(name string) *Group { |
| 375 | if grp := c.Group.groupByName(name); grp != nil { |
| 376 | return grp |
| 377 | } |
| 378 | |
| 379 | for _, subc := range c.commands { |
| 380 | prefix := subc.Name + "." |
| 381 | |
| 382 | if strings.HasPrefix(name, prefix) { |
| 383 | if grp := subc.groupByName(name[len(prefix):]); grp != nil { |
| 384 | return grp |
| 385 | } |
| 386 | } else if name == subc.Name { |
| 387 | return subc.Group |
| 388 | } |
| 389 | } |
| 390 | |
| 391 | return nil |
| 392 | } |
| 393 | |
| 394 | type commandList []*Command |
| 395 | |
| 396 | func (c commandList) Less(i, j int) bool { |
| 397 | return c[i].Name < c[j].Name |
| 398 | } |
| 399 | |
| 400 | func (c commandList) Len() int { |
| 401 | return len(c) |
| 402 | } |
| 403 | |
| 404 | func (c commandList) Swap(i, j int) { |
| 405 | c[i], c[j] = c[j], c[i] |
| 406 | } |
| 407 | |
| 408 | func (c *Command) sortedVisibleCommands() []*Command { |
| 409 | ret := commandList(c.visibleCommands()) |
| 410 | sort.Sort(ret) |
| 411 | |
| 412 | return []*Command(ret) |
| 413 | } |
| 414 | |
| 415 | func (c *Command) visibleCommands() []*Command { |
| 416 | ret := make([]*Command, 0, len(c.commands)) |
| 417 | |
| 418 | for _, cmd := range c.commands { |
| 419 | if !cmd.Hidden { |
| 420 | ret = append(ret, cmd) |
| 421 | } |
| 422 | } |
| 423 | |
| 424 | return ret |
| 425 | } |
| 426 | |
| 427 | func (c *Command) match(name string) bool { |
| 428 | if c.Name == name { |
| 429 | return true |
| 430 | } |
| 431 | |
| 432 | for _, v := range c.Aliases { |
| 433 | if v == name { |
| 434 | return true |
| 435 | } |
| 436 | } |
| 437 | |
| 438 | return false |
| 439 | } |
| 440 | |
| 441 | func (c *Command) hasCliOptions() bool { |
| 442 | ret := false |
| 443 | |
| 444 | c.eachGroup(func(g *Group) { |
| 445 | if g.isBuiltinHelp { |
| 446 | return |
| 447 | } |
| 448 | |
| 449 | for _, opt := range g.options { |
| 450 | if opt.canCli() { |
| 451 | ret = true |
| 452 | } |
| 453 | } |
| 454 | }) |
| 455 | |
| 456 | return ret |
| 457 | } |
| 458 | |
| 459 | func (c *Command) fillParseState(s *parseState) { |
| 460 | s.positional = make([]*Arg, len(c.args)) |
| 461 | copy(s.positional, c.args) |
| 462 | |
| 463 | s.lookup = c.makeLookup() |
| 464 | s.command = c |
| 465 | } |