Andrew Walbran | dc8aa4b | 2022-01-13 12:20:07 +0000 | [diff] [blame] | 1 | #![recursion_limit = "256"] |
| 2 | // Copyright (c) 2020 Google LLC All rights reserved. |
| 3 | // Use of this source code is governed by a BSD-style |
| 4 | // license that can be found in the LICENSE file. |
| 5 | |
| 6 | /// Implementation of the `FromArgs` and `argh(...)` derive attributes. |
| 7 | /// |
| 8 | /// For more thorough documentation, see the `argh` crate itself. |
| 9 | extern crate proc_macro; |
| 10 | |
| 11 | use { |
| 12 | crate::{ |
| 13 | errors::Errors, |
| 14 | parse_attrs::{FieldAttrs, FieldKind, TypeAttrs}, |
| 15 | }, |
| 16 | proc_macro2::{Span, TokenStream}, |
| 17 | quote::{quote, quote_spanned, ToTokens}, |
| 18 | std::str::FromStr, |
| 19 | syn::{spanned::Spanned, LitStr}, |
| 20 | }; |
| 21 | |
| 22 | mod errors; |
| 23 | mod help; |
| 24 | mod parse_attrs; |
| 25 | |
| 26 | /// Entrypoint for `#[derive(FromArgs)]`. |
| 27 | #[proc_macro_derive(FromArgs, attributes(argh))] |
| 28 | pub fn argh_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream { |
| 29 | let ast = syn::parse_macro_input!(input as syn::DeriveInput); |
| 30 | let gen = impl_from_args(&ast); |
| 31 | gen.into() |
| 32 | } |
| 33 | |
| 34 | /// Transform the input into a token stream containing any generated implementations, |
| 35 | /// as well as all errors that occurred. |
| 36 | fn impl_from_args(input: &syn::DeriveInput) -> TokenStream { |
| 37 | let errors = &Errors::default(); |
| 38 | if input.generics.params.len() != 0 { |
| 39 | errors.err( |
| 40 | &input.generics, |
| 41 | "`#![derive(FromArgs)]` cannot be applied to types with generic parameters", |
| 42 | ); |
| 43 | } |
| 44 | let type_attrs = &TypeAttrs::parse(errors, input); |
| 45 | let mut output_tokens = match &input.data { |
| 46 | syn::Data::Struct(ds) => impl_from_args_struct(errors, &input.ident, type_attrs, ds), |
| 47 | syn::Data::Enum(de) => impl_from_args_enum(errors, &input.ident, type_attrs, de), |
| 48 | syn::Data::Union(_) => { |
| 49 | errors.err(input, "`#[derive(FromArgs)]` cannot be applied to unions"); |
| 50 | TokenStream::new() |
| 51 | } |
| 52 | }; |
| 53 | errors.to_tokens(&mut output_tokens); |
| 54 | output_tokens |
| 55 | } |
| 56 | |
| 57 | /// The kind of optionality a parameter has. |
| 58 | enum Optionality { |
| 59 | None, |
| 60 | Defaulted(TokenStream), |
| 61 | Optional, |
| 62 | Repeating, |
| 63 | } |
| 64 | |
| 65 | impl PartialEq<Optionality> for Optionality { |
| 66 | fn eq(&self, other: &Optionality) -> bool { |
| 67 | use Optionality::*; |
| 68 | match (self, other) { |
| 69 | (None, None) | (Optional, Optional) | (Repeating, Repeating) => true, |
| 70 | // NB: (Defaulted, Defaulted) can't contain the same token streams |
| 71 | _ => false, |
| 72 | } |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | impl Optionality { |
| 77 | /// Whether or not this is `Optionality::None` |
| 78 | fn is_required(&self) -> bool { |
| 79 | if let Optionality::None = self { |
| 80 | true |
| 81 | } else { |
| 82 | false |
| 83 | } |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | /// A field of a `#![derive(FromArgs)]` struct with attributes and some other |
| 88 | /// notable metadata appended. |
| 89 | struct StructField<'a> { |
| 90 | /// The original parsed field |
| 91 | field: &'a syn::Field, |
| 92 | /// The parsed attributes of the field |
| 93 | attrs: FieldAttrs, |
| 94 | /// The field name. This is contained optionally inside `field`, |
| 95 | /// but is duplicated non-optionally here to indicate that all field that |
| 96 | /// have reached this point must have a field name, and it no longer |
| 97 | /// needs to be unwrapped. |
| 98 | name: &'a syn::Ident, |
| 99 | /// Similar to `name` above, this is contained optionally inside `FieldAttrs`, |
| 100 | /// but here is fully present to indicate that we only have to consider fields |
| 101 | /// with a valid `kind` at this point. |
| 102 | kind: FieldKind, |
| 103 | // If `field.ty` is `Vec<T>` or `Option<T>`, this is `T`, otherwise it's `&field.ty`. |
| 104 | // This is used to enable consistent parsing code between optional and non-optional |
| 105 | // keyed and subcommand fields. |
| 106 | ty_without_wrapper: &'a syn::Type, |
| 107 | // Whether the field represents an optional value, such as an `Option` subcommand field |
| 108 | // or an `Option` or `Vec` keyed argument, or if it has a `default`. |
| 109 | optionality: Optionality, |
| 110 | // The `--`-prefixed name of the option, if one exists. |
| 111 | long_name: Option<String>, |
| 112 | } |
| 113 | |
| 114 | impl<'a> StructField<'a> { |
| 115 | /// Attempts to parse a field of a `#[derive(FromArgs)]` struct, pulling out the |
| 116 | /// fields required for code generation. |
| 117 | fn new(errors: &Errors, field: &'a syn::Field, attrs: FieldAttrs) -> Option<Self> { |
| 118 | let name = field.ident.as_ref().expect("missing ident for named field"); |
| 119 | |
| 120 | // Ensure that one "kind" is present (switch, option, subcommand, positional) |
| 121 | let kind = if let Some(field_type) = &attrs.field_type { |
| 122 | field_type.kind |
| 123 | } else { |
| 124 | errors.err( |
| 125 | field, |
| 126 | concat!( |
| 127 | "Missing `argh` field kind attribute.\n", |
| 128 | "Expected one of: `switch`, `option`, `subcommand`, `positional`", |
| 129 | ), |
| 130 | ); |
| 131 | return None; |
| 132 | }; |
| 133 | |
| 134 | // Parse out whether a field is optional (`Option` or `Vec`). |
| 135 | let optionality; |
| 136 | let ty_without_wrapper; |
| 137 | match kind { |
| 138 | FieldKind::Switch => { |
| 139 | if !ty_expect_switch(errors, &field.ty) { |
| 140 | return None; |
| 141 | } |
| 142 | optionality = Optionality::Optional; |
| 143 | ty_without_wrapper = &field.ty; |
| 144 | } |
| 145 | FieldKind::Option | FieldKind::Positional => { |
| 146 | if let Some(default) = &attrs.default { |
| 147 | let tokens = match TokenStream::from_str(&default.value()) { |
| 148 | Ok(tokens) => tokens, |
| 149 | Err(_) => { |
| 150 | errors.err(&default, "Invalid tokens: unable to lex `default` value"); |
| 151 | return None; |
| 152 | } |
| 153 | }; |
| 154 | // Set the span of the generated tokens to the string literal |
| 155 | let tokens: TokenStream = tokens |
| 156 | .into_iter() |
| 157 | .map(|mut tree| { |
| 158 | tree.set_span(default.span()); |
| 159 | tree |
| 160 | }) |
| 161 | .collect(); |
| 162 | optionality = Optionality::Defaulted(tokens); |
| 163 | ty_without_wrapper = &field.ty; |
| 164 | } else { |
| 165 | let mut inner = None; |
| 166 | optionality = if let Some(x) = ty_inner(&["Option"], &field.ty) { |
| 167 | inner = Some(x); |
| 168 | Optionality::Optional |
| 169 | } else if let Some(x) = ty_inner(&["Vec"], &field.ty) { |
| 170 | inner = Some(x); |
| 171 | Optionality::Repeating |
| 172 | } else { |
| 173 | Optionality::None |
| 174 | }; |
| 175 | ty_without_wrapper = inner.unwrap_or(&field.ty); |
| 176 | } |
| 177 | } |
| 178 | FieldKind::SubCommand => { |
| 179 | let inner = ty_inner(&["Option"], &field.ty); |
| 180 | optionality = |
| 181 | if inner.is_some() { Optionality::Optional } else { Optionality::None }; |
| 182 | ty_without_wrapper = inner.unwrap_or(&field.ty); |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | // Determine the "long" name of options and switches. |
| 187 | // Defaults to the kebab-case'd field name if `#[argh(long = "...")]` is omitted. |
| 188 | let long_name = match kind { |
| 189 | FieldKind::Switch | FieldKind::Option => { |
| 190 | let long_name = attrs |
| 191 | .long |
| 192 | .as_ref() |
| 193 | .map(syn::LitStr::value) |
| 194 | .unwrap_or_else(|| heck::KebabCase::to_kebab_case(&*name.to_string())); |
| 195 | if long_name == "help" { |
| 196 | errors.err(field, "Custom `--help` flags are not supported."); |
| 197 | } |
| 198 | let long_name = format!("--{}", long_name); |
| 199 | Some(long_name) |
| 200 | } |
| 201 | FieldKind::SubCommand | FieldKind::Positional => None, |
| 202 | }; |
| 203 | |
| 204 | Some(StructField { field, attrs, kind, optionality, ty_without_wrapper, name, long_name }) |
| 205 | } |
| 206 | |
| 207 | pub(crate) fn arg_name(&self) -> String { |
| 208 | self.attrs.arg_name.as_ref().map(LitStr::value).unwrap_or_else(|| self.name.to_string()) |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | /// Implements `FromArgs` and `TopLevelCommand` or `SubCommand` for a `#[derive(FromArgs)]` struct. |
| 213 | fn impl_from_args_struct( |
| 214 | errors: &Errors, |
| 215 | name: &syn::Ident, |
| 216 | type_attrs: &TypeAttrs, |
| 217 | ds: &syn::DataStruct, |
| 218 | ) -> TokenStream { |
| 219 | let fields = match &ds.fields { |
| 220 | syn::Fields::Named(fields) => fields, |
| 221 | syn::Fields::Unnamed(_) => { |
| 222 | errors.err( |
| 223 | &ds.struct_token, |
| 224 | "`#![derive(FromArgs)]` is not currently supported on tuple structs", |
| 225 | ); |
| 226 | return TokenStream::new(); |
| 227 | } |
| 228 | syn::Fields::Unit => { |
| 229 | errors.err(&ds.struct_token, "#![derive(FromArgs)]` cannot be applied to unit structs"); |
| 230 | return TokenStream::new(); |
| 231 | } |
| 232 | }; |
| 233 | |
| 234 | let fields: Vec<_> = fields |
| 235 | .named |
| 236 | .iter() |
| 237 | .filter_map(|field| { |
| 238 | let attrs = FieldAttrs::parse(errors, field); |
| 239 | StructField::new(errors, field, attrs) |
| 240 | }) |
| 241 | .collect(); |
| 242 | |
| 243 | ensure_only_last_positional_is_optional(errors, &fields); |
| 244 | |
| 245 | let impl_span = Span::call_site(); |
| 246 | |
| 247 | let from_args_method = impl_from_args_struct_from_args(errors, type_attrs, &fields); |
| 248 | |
| 249 | let redact_arg_values_method = |
| 250 | impl_from_args_struct_redact_arg_values(errors, type_attrs, &fields); |
| 251 | |
| 252 | let top_or_sub_cmd_impl = top_or_sub_cmd_impl(errors, name, type_attrs); |
| 253 | |
| 254 | let trait_impl = quote_spanned! { impl_span => |
| 255 | impl argh::FromArgs for #name { |
| 256 | #from_args_method |
| 257 | |
| 258 | #redact_arg_values_method |
| 259 | } |
| 260 | |
| 261 | #top_or_sub_cmd_impl |
| 262 | }; |
| 263 | |
| 264 | trait_impl |
| 265 | } |
| 266 | |
| 267 | fn impl_from_args_struct_from_args<'a>( |
| 268 | errors: &Errors, |
| 269 | type_attrs: &TypeAttrs, |
| 270 | fields: &'a [StructField<'a>], |
| 271 | ) -> TokenStream { |
| 272 | let init_fields = declare_local_storage_for_from_args_fields(&fields); |
| 273 | let unwrap_fields = unwrap_from_args_fields(&fields); |
| 274 | let positional_fields: Vec<&StructField<'_>> = |
| 275 | fields.iter().filter(|field| field.kind == FieldKind::Positional).collect(); |
| 276 | let positional_field_idents = positional_fields.iter().map(|field| &field.field.ident); |
| 277 | let positional_field_names = positional_fields.iter().map(|field| field.name.to_string()); |
| 278 | let last_positional_is_repeating = positional_fields |
| 279 | .last() |
| 280 | .map(|field| field.optionality == Optionality::Repeating) |
| 281 | .unwrap_or(false); |
| 282 | |
| 283 | let flag_output_table = fields.iter().filter_map(|field| { |
| 284 | let field_name = &field.field.ident; |
| 285 | match field.kind { |
| 286 | FieldKind::Option => Some(quote! { argh::ParseStructOption::Value(&mut #field_name) }), |
| 287 | FieldKind::Switch => Some(quote! { argh::ParseStructOption::Flag(&mut #field_name) }), |
| 288 | FieldKind::SubCommand | FieldKind::Positional => None, |
| 289 | } |
| 290 | }); |
| 291 | |
| 292 | let flag_str_to_output_table_map = flag_str_to_output_table_map_entries(&fields); |
| 293 | |
| 294 | let mut subcommands_iter = |
| 295 | fields.iter().filter(|field| field.kind == FieldKind::SubCommand).fuse(); |
| 296 | |
| 297 | let subcommand: Option<&StructField<'_>> = subcommands_iter.next(); |
| 298 | while let Some(dup_subcommand) = subcommands_iter.next() { |
| 299 | errors.duplicate_attrs("subcommand", subcommand.unwrap().field, dup_subcommand.field); |
| 300 | } |
| 301 | |
| 302 | let impl_span = Span::call_site(); |
| 303 | |
| 304 | let missing_requirements_ident = syn::Ident::new("__missing_requirements", impl_span); |
| 305 | |
| 306 | let append_missing_requirements = |
| 307 | append_missing_requirements(&missing_requirements_ident, &fields); |
| 308 | |
| 309 | let parse_subcommands = if let Some(subcommand) = subcommand { |
| 310 | let name = subcommand.name; |
| 311 | let ty = subcommand.ty_without_wrapper; |
| 312 | quote_spanned! { impl_span => |
| 313 | Some(argh::ParseStructSubCommand { |
| 314 | subcommands: <#ty as argh::SubCommands>::COMMANDS, |
| 315 | parse_func: &mut |__command, __remaining_args| { |
| 316 | #name = Some(<#ty as argh::FromArgs>::from_args(__command, __remaining_args)?); |
| 317 | Ok(()) |
| 318 | }, |
| 319 | }) |
| 320 | } |
| 321 | } else { |
| 322 | quote_spanned! { impl_span => None } |
| 323 | }; |
| 324 | |
| 325 | // Identifier referring to a value containing the name of the current command as an `&[&str]`. |
| 326 | let cmd_name_str_array_ident = syn::Ident::new("__cmd_name", impl_span); |
| 327 | let help = help::help(errors, cmd_name_str_array_ident, type_attrs, &fields, subcommand); |
| 328 | |
| 329 | let method_impl = quote_spanned! { impl_span => |
| 330 | fn from_args(__cmd_name: &[&str], __args: &[&str]) |
| 331 | -> std::result::Result<Self, argh::EarlyExit> |
| 332 | { |
| 333 | #( #init_fields )* |
| 334 | |
| 335 | argh::parse_struct_args( |
| 336 | __cmd_name, |
| 337 | __args, |
| 338 | argh::ParseStructOptions { |
| 339 | arg_to_slot: &[ #( #flag_str_to_output_table_map ,)* ], |
| 340 | slots: &mut [ #( #flag_output_table, )* ], |
| 341 | }, |
| 342 | argh::ParseStructPositionals { |
| 343 | positionals: &mut [ |
| 344 | #( |
| 345 | argh::ParseStructPositional { |
| 346 | name: #positional_field_names, |
| 347 | slot: &mut #positional_field_idents as &mut argh::ParseValueSlot, |
| 348 | }, |
| 349 | )* |
| 350 | ], |
| 351 | last_is_repeating: #last_positional_is_repeating, |
| 352 | }, |
| 353 | #parse_subcommands, |
| 354 | &|| #help, |
| 355 | )?; |
| 356 | |
| 357 | let mut #missing_requirements_ident = argh::MissingRequirements::default(); |
| 358 | #( |
| 359 | #append_missing_requirements |
| 360 | )* |
| 361 | #missing_requirements_ident.err_on_any()?; |
| 362 | |
| 363 | Ok(Self { |
| 364 | #( #unwrap_fields, )* |
| 365 | }) |
| 366 | } |
| 367 | }; |
| 368 | |
| 369 | method_impl |
| 370 | } |
| 371 | |
| 372 | fn impl_from_args_struct_redact_arg_values<'a>( |
| 373 | errors: &Errors, |
| 374 | type_attrs: &TypeAttrs, |
| 375 | fields: &'a [StructField<'a>], |
| 376 | ) -> TokenStream { |
| 377 | let init_fields = declare_local_storage_for_redacted_fields(&fields); |
| 378 | let unwrap_fields = unwrap_redacted_fields(&fields); |
| 379 | |
| 380 | let positional_fields: Vec<&StructField<'_>> = |
| 381 | fields.iter().filter(|field| field.kind == FieldKind::Positional).collect(); |
| 382 | let positional_field_idents = positional_fields.iter().map(|field| &field.field.ident); |
| 383 | let positional_field_names = positional_fields.iter().map(|field| field.name.to_string()); |
| 384 | let last_positional_is_repeating = positional_fields |
| 385 | .last() |
| 386 | .map(|field| field.optionality == Optionality::Repeating) |
| 387 | .unwrap_or(false); |
| 388 | |
| 389 | let flag_output_table = fields.iter().filter_map(|field| { |
| 390 | let field_name = &field.field.ident; |
| 391 | match field.kind { |
| 392 | FieldKind::Option => Some(quote! { argh::ParseStructOption::Value(&mut #field_name) }), |
| 393 | FieldKind::Switch => Some(quote! { argh::ParseStructOption::Flag(&mut #field_name) }), |
| 394 | FieldKind::SubCommand | FieldKind::Positional => None, |
| 395 | } |
| 396 | }); |
| 397 | |
| 398 | let flag_str_to_output_table_map = flag_str_to_output_table_map_entries(&fields); |
| 399 | |
| 400 | let mut subcommands_iter = |
| 401 | fields.iter().filter(|field| field.kind == FieldKind::SubCommand).fuse(); |
| 402 | |
| 403 | let subcommand: Option<&StructField<'_>> = subcommands_iter.next(); |
| 404 | while let Some(dup_subcommand) = subcommands_iter.next() { |
| 405 | errors.duplicate_attrs("subcommand", subcommand.unwrap().field, dup_subcommand.field); |
| 406 | } |
| 407 | |
| 408 | let impl_span = Span::call_site(); |
| 409 | |
| 410 | let missing_requirements_ident = syn::Ident::new("__missing_requirements", impl_span); |
| 411 | |
| 412 | let append_missing_requirements = |
| 413 | append_missing_requirements(&missing_requirements_ident, &fields); |
| 414 | |
| 415 | let redact_subcommands = if let Some(subcommand) = subcommand { |
| 416 | let name = subcommand.name; |
| 417 | let ty = subcommand.ty_without_wrapper; |
| 418 | quote_spanned! { impl_span => |
| 419 | Some(argh::ParseStructSubCommand { |
| 420 | subcommands: <#ty as argh::SubCommands>::COMMANDS, |
| 421 | parse_func: &mut |__command, __remaining_args| { |
| 422 | #name = Some(<#ty as argh::FromArgs>::redact_arg_values(__command, __remaining_args)?); |
| 423 | Ok(()) |
| 424 | }, |
| 425 | }) |
| 426 | } |
| 427 | } else { |
| 428 | quote_spanned! { impl_span => None } |
| 429 | }; |
| 430 | |
| 431 | let cmd_name = if type_attrs.is_subcommand.is_none() { |
| 432 | quote! { __cmd_name.last().expect("no command name").to_string() } |
| 433 | } else { |
| 434 | quote! { __cmd_name.last().expect("no subcommand name").to_string() } |
| 435 | }; |
| 436 | |
| 437 | // Identifier referring to a value containing the name of the current command as an `&[&str]`. |
| 438 | let cmd_name_str_array_ident = syn::Ident::new("__cmd_name", impl_span); |
| 439 | let help = help::help(errors, cmd_name_str_array_ident, type_attrs, &fields, subcommand); |
| 440 | |
| 441 | let method_impl = quote_spanned! { impl_span => |
| 442 | fn redact_arg_values(__cmd_name: &[&str], __args: &[&str]) -> std::result::Result<Vec<String>, argh::EarlyExit> { |
| 443 | #( #init_fields )* |
| 444 | |
| 445 | argh::parse_struct_args( |
| 446 | __cmd_name, |
| 447 | __args, |
| 448 | argh::ParseStructOptions { |
| 449 | arg_to_slot: &[ #( #flag_str_to_output_table_map ,)* ], |
| 450 | slots: &mut [ #( #flag_output_table, )* ], |
| 451 | }, |
| 452 | argh::ParseStructPositionals { |
| 453 | positionals: &mut [ |
| 454 | #( |
| 455 | argh::ParseStructPositional { |
| 456 | name: #positional_field_names, |
| 457 | slot: &mut #positional_field_idents as &mut argh::ParseValueSlot, |
| 458 | }, |
| 459 | )* |
| 460 | ], |
| 461 | last_is_repeating: #last_positional_is_repeating, |
| 462 | }, |
| 463 | #redact_subcommands, |
| 464 | &|| #help, |
| 465 | )?; |
| 466 | |
| 467 | let mut #missing_requirements_ident = argh::MissingRequirements::default(); |
| 468 | #( |
| 469 | #append_missing_requirements |
| 470 | )* |
| 471 | #missing_requirements_ident.err_on_any()?; |
| 472 | |
| 473 | let mut __redacted = vec![ |
| 474 | #cmd_name, |
| 475 | ]; |
| 476 | |
| 477 | #( #unwrap_fields )* |
| 478 | |
| 479 | Ok(__redacted) |
| 480 | } |
| 481 | }; |
| 482 | |
| 483 | method_impl |
| 484 | } |
| 485 | |
| 486 | /// Ensures that only the last positional arg is non-required. |
| 487 | fn ensure_only_last_positional_is_optional(errors: &Errors, fields: &[StructField<'_>]) { |
| 488 | let mut first_non_required_span = None; |
| 489 | for field in fields { |
| 490 | if field.kind == FieldKind::Positional { |
| 491 | if let Some(first) = first_non_required_span { |
| 492 | errors.err_span( |
| 493 | first, |
| 494 | "Only the last positional argument may be `Option`, `Vec`, or defaulted.", |
| 495 | ); |
| 496 | errors.err(&field.field, "Later positional argument declared here."); |
| 497 | return; |
| 498 | } |
| 499 | if !field.optionality.is_required() { |
| 500 | first_non_required_span = Some(field.field.span()); |
| 501 | } |
| 502 | } |
| 503 | } |
| 504 | } |
| 505 | |
| 506 | /// Implement `argh::TopLevelCommand` or `argh::SubCommand` as appropriate. |
| 507 | fn top_or_sub_cmd_impl(errors: &Errors, name: &syn::Ident, type_attrs: &TypeAttrs) -> TokenStream { |
| 508 | let description = |
| 509 | help::require_description(errors, name.span(), &type_attrs.description, "type"); |
| 510 | if type_attrs.is_subcommand.is_none() { |
| 511 | // Not a subcommand |
| 512 | quote! { |
| 513 | impl argh::TopLevelCommand for #name {} |
| 514 | } |
| 515 | } else { |
| 516 | let empty_str = syn::LitStr::new("", Span::call_site()); |
| 517 | let subcommand_name = type_attrs.name.as_ref().unwrap_or_else(|| { |
| 518 | errors.err(name, "`#[argh(name = \"...\")]` attribute is required for subcommands"); |
| 519 | &empty_str |
| 520 | }); |
| 521 | quote! { |
| 522 | impl argh::SubCommand for #name { |
| 523 | const COMMAND: &'static argh::CommandInfo = &argh::CommandInfo { |
| 524 | name: #subcommand_name, |
| 525 | description: #description, |
| 526 | }; |
| 527 | } |
| 528 | } |
| 529 | } |
| 530 | } |
| 531 | |
| 532 | /// Declare a local slots to store each field in during parsing. |
| 533 | /// |
| 534 | /// Most fields are stored in `Option<FieldType>` locals. |
| 535 | /// `argh(option)` fields are stored in a `ParseValueSlotTy` along with a |
| 536 | /// function that knows how to decode the appropriate value. |
| 537 | fn declare_local_storage_for_from_args_fields<'a>( |
| 538 | fields: &'a [StructField<'a>], |
| 539 | ) -> impl Iterator<Item = TokenStream> + 'a { |
| 540 | fields.iter().map(|field| { |
| 541 | let field_name = &field.field.ident; |
| 542 | let field_type = &field.ty_without_wrapper; |
| 543 | |
| 544 | // Wrap field types in `Option` if they aren't already `Option` or `Vec`-wrapped. |
| 545 | let field_slot_type = match field.optionality { |
| 546 | Optionality::Optional | Optionality::Repeating => (&field.field.ty).into_token_stream(), |
| 547 | Optionality::None | Optionality::Defaulted(_) => { |
| 548 | quote! { std::option::Option<#field_type> } |
| 549 | } |
| 550 | }; |
| 551 | |
| 552 | match field.kind { |
| 553 | FieldKind::Option | FieldKind::Positional => { |
| 554 | let from_str_fn = match &field.attrs.from_str_fn { |
| 555 | Some(from_str_fn) => from_str_fn.into_token_stream(), |
| 556 | None => { |
| 557 | quote! { |
| 558 | <#field_type as argh::FromArgValue>::from_arg_value |
| 559 | } |
| 560 | } |
| 561 | }; |
| 562 | |
| 563 | quote! { |
| 564 | let mut #field_name: argh::ParseValueSlotTy<#field_slot_type, #field_type> |
| 565 | = argh::ParseValueSlotTy { |
| 566 | slot: std::default::Default::default(), |
| 567 | parse_func: |_, value| { #from_str_fn(value) }, |
| 568 | }; |
| 569 | } |
| 570 | } |
| 571 | FieldKind::SubCommand => { |
| 572 | quote! { let mut #field_name: #field_slot_type = None; } |
| 573 | } |
| 574 | FieldKind::Switch => { |
| 575 | quote! { let mut #field_name: #field_slot_type = argh::Flag::default(); } |
| 576 | } |
| 577 | } |
| 578 | }) |
| 579 | } |
| 580 | |
| 581 | /// Unwrap non-optional fields and take options out of their tuple slots. |
| 582 | fn unwrap_from_args_fields<'a>( |
| 583 | fields: &'a [StructField<'a>], |
| 584 | ) -> impl Iterator<Item = TokenStream> + 'a { |
| 585 | fields.iter().map(|field| { |
| 586 | let field_name = field.name; |
| 587 | match field.kind { |
| 588 | FieldKind::Option | FieldKind::Positional => match &field.optionality { |
| 589 | Optionality::None => quote! { #field_name: #field_name.slot.unwrap() }, |
| 590 | Optionality::Optional | Optionality::Repeating => { |
| 591 | quote! { #field_name: #field_name.slot } |
| 592 | } |
| 593 | Optionality::Defaulted(tokens) => { |
| 594 | quote! { |
| 595 | #field_name: #field_name.slot.unwrap_or_else(|| #tokens) |
| 596 | } |
| 597 | } |
| 598 | }, |
| 599 | FieldKind::Switch => field_name.into_token_stream(), |
| 600 | FieldKind::SubCommand => match field.optionality { |
| 601 | Optionality::None => quote! { #field_name: #field_name.unwrap() }, |
| 602 | Optionality::Optional | Optionality::Repeating => field_name.into_token_stream(), |
| 603 | Optionality::Defaulted(_) => unreachable!(), |
| 604 | }, |
| 605 | } |
| 606 | }) |
| 607 | } |
| 608 | |
| 609 | /// Declare a local slots to store each field in during parsing. |
| 610 | /// |
| 611 | /// Most fields are stored in `Option<FieldType>` locals. |
| 612 | /// `argh(option)` fields are stored in a `ParseValueSlotTy` along with a |
| 613 | /// function that knows how to decode the appropriate value. |
| 614 | fn declare_local_storage_for_redacted_fields<'a>( |
| 615 | fields: &'a [StructField<'a>], |
| 616 | ) -> impl Iterator<Item = TokenStream> + 'a { |
| 617 | fields.iter().map(|field| { |
| 618 | let field_name = &field.field.ident; |
| 619 | |
| 620 | match field.kind { |
| 621 | FieldKind::Switch => { |
| 622 | quote! { |
| 623 | let mut #field_name = argh::RedactFlag { |
| 624 | slot: None, |
| 625 | }; |
| 626 | } |
| 627 | } |
| 628 | FieldKind::Option => { |
| 629 | let field_slot_type = match field.optionality { |
| 630 | Optionality::Repeating => { |
| 631 | quote! { std::vec::Vec<String> } |
| 632 | } |
| 633 | Optionality::None | Optionality::Optional | Optionality::Defaulted(_) => { |
| 634 | quote! { std::option::Option<String> } |
| 635 | } |
| 636 | }; |
| 637 | |
| 638 | quote! { |
| 639 | let mut #field_name: argh::ParseValueSlotTy::<#field_slot_type, String> = |
| 640 | argh::ParseValueSlotTy { |
| 641 | slot: std::default::Default::default(), |
| 642 | parse_func: |arg, _| { Ok(arg.to_string()) }, |
| 643 | }; |
| 644 | } |
| 645 | } |
| 646 | FieldKind::Positional => { |
| 647 | let field_slot_type = match field.optionality { |
| 648 | Optionality::Repeating => { |
| 649 | quote! { std::vec::Vec<String> } |
| 650 | } |
| 651 | Optionality::None | Optionality::Optional | Optionality::Defaulted(_) => { |
| 652 | quote! { std::option::Option<String> } |
| 653 | } |
| 654 | }; |
| 655 | |
| 656 | let arg_name = field.arg_name(); |
| 657 | quote! { |
| 658 | let mut #field_name: argh::ParseValueSlotTy::<#field_slot_type, String> = |
| 659 | argh::ParseValueSlotTy { |
| 660 | slot: std::default::Default::default(), |
| 661 | parse_func: |_, _| { Ok(#arg_name.to_string()) }, |
| 662 | }; |
| 663 | } |
| 664 | } |
| 665 | FieldKind::SubCommand => { |
| 666 | quote! { let mut #field_name: std::option::Option<std::vec::Vec<String>> = None; } |
| 667 | } |
| 668 | } |
| 669 | }) |
| 670 | } |
| 671 | |
| 672 | /// Unwrap non-optional fields and take options out of their tuple slots. |
| 673 | fn unwrap_redacted_fields<'a>( |
| 674 | fields: &'a [StructField<'a>], |
| 675 | ) -> impl Iterator<Item = TokenStream> + 'a { |
| 676 | fields.iter().map(|field| { |
| 677 | let field_name = field.name; |
| 678 | |
| 679 | match field.kind { |
| 680 | FieldKind::Switch => { |
| 681 | quote! { |
| 682 | if let Some(__field_name) = #field_name.slot { |
| 683 | __redacted.push(__field_name); |
| 684 | } |
| 685 | } |
| 686 | } |
| 687 | FieldKind::Option => match field.optionality { |
| 688 | Optionality::Repeating => { |
| 689 | quote! { |
| 690 | __redacted.extend(#field_name.slot.into_iter()); |
| 691 | } |
| 692 | } |
| 693 | Optionality::None | Optionality::Optional | Optionality::Defaulted(_) => { |
| 694 | quote! { |
| 695 | if let Some(__field_name) = #field_name.slot { |
| 696 | __redacted.push(__field_name); |
| 697 | } |
| 698 | } |
| 699 | } |
| 700 | }, |
| 701 | FieldKind::Positional => { |
| 702 | quote! { |
| 703 | __redacted.extend(#field_name.slot.into_iter()); |
| 704 | } |
| 705 | } |
| 706 | FieldKind::SubCommand => { |
| 707 | quote! { |
| 708 | if let Some(__subcommand_args) = #field_name { |
| 709 | __redacted.extend(__subcommand_args.into_iter()); |
| 710 | } |
| 711 | } |
| 712 | } |
| 713 | } |
| 714 | }) |
| 715 | } |
| 716 | |
| 717 | /// Entries of tokens like `("--some-flag-key", 5)` that map from a flag key string |
| 718 | /// to an index in the output table. |
| 719 | fn flag_str_to_output_table_map_entries<'a>(fields: &'a [StructField<'a>]) -> Vec<TokenStream> { |
| 720 | let mut flag_str_to_output_table_map = vec![]; |
| 721 | for (i, (field, long_name)) in fields |
| 722 | .iter() |
| 723 | .filter_map(|field| field.long_name.as_ref().map(|long_name| (field, long_name))) |
| 724 | .enumerate() |
| 725 | { |
| 726 | if let Some(short) = &field.attrs.short { |
| 727 | let short = format!("-{}", short.value()); |
| 728 | flag_str_to_output_table_map.push(quote! { (#short, #i) }); |
| 729 | } |
| 730 | |
| 731 | flag_str_to_output_table_map.push(quote! { (#long_name, #i) }); |
| 732 | } |
| 733 | flag_str_to_output_table_map |
| 734 | } |
| 735 | |
| 736 | /// For each non-optional field, add an entry to the `argh::MissingRequirements`. |
| 737 | fn append_missing_requirements<'a>( |
| 738 | // missing_requirements_ident |
| 739 | mri: &syn::Ident, |
| 740 | fields: &'a [StructField<'a>], |
| 741 | ) -> impl Iterator<Item = TokenStream> + 'a { |
| 742 | let mri = mri.clone(); |
| 743 | fields.iter().filter(|f| f.optionality.is_required()).map(move |field| { |
| 744 | let field_name = field.name; |
| 745 | match field.kind { |
| 746 | FieldKind::Switch => unreachable!("switches are always optional"), |
| 747 | FieldKind::Positional => { |
| 748 | let name = field.arg_name(); |
| 749 | quote! { |
| 750 | if #field_name.slot.is_none() { |
| 751 | #mri.missing_positional_arg(#name) |
| 752 | } |
| 753 | } |
| 754 | } |
| 755 | FieldKind::Option => { |
| 756 | let name = field.long_name.as_ref().expect("options always have a long name"); |
| 757 | quote! { |
| 758 | if #field_name.slot.is_none() { |
| 759 | #mri.missing_option(#name) |
| 760 | } |
| 761 | } |
| 762 | } |
| 763 | FieldKind::SubCommand => { |
| 764 | let ty = field.ty_without_wrapper; |
| 765 | quote! { |
| 766 | if #field_name.is_none() { |
| 767 | #mri.missing_subcommands( |
| 768 | <#ty as argh::SubCommands>::COMMANDS, |
| 769 | ) |
| 770 | } |
| 771 | } |
| 772 | } |
| 773 | } |
| 774 | }) |
| 775 | } |
| 776 | |
| 777 | /// Require that a type can be a `switch`. |
| 778 | /// Throws an error for all types except booleans and integers |
| 779 | fn ty_expect_switch(errors: &Errors, ty: &syn::Type) -> bool { |
| 780 | fn ty_can_be_switch(ty: &syn::Type) -> bool { |
| 781 | if let syn::Type::Path(path) = ty { |
| 782 | if path.qself.is_some() { |
| 783 | return false; |
| 784 | } |
| 785 | if path.path.segments.len() != 1 { |
| 786 | return false; |
| 787 | } |
| 788 | let ident = &path.path.segments[0].ident; |
| 789 | ["bool", "u8", "u16", "u32", "u64", "u128", "i8", "i16", "i32", "i64", "i128"] |
| 790 | .iter() |
| 791 | .any(|path| ident == path) |
| 792 | } else { |
| 793 | false |
| 794 | } |
| 795 | } |
| 796 | |
| 797 | let res = ty_can_be_switch(ty); |
| 798 | if !res { |
| 799 | errors.err(ty, "switches must be of type `bool` or integer type"); |
| 800 | } |
| 801 | res |
| 802 | } |
| 803 | |
| 804 | /// Returns `Some(T)` if a type is `wrapper_name<T>` for any `wrapper_name` in `wrapper_names`. |
| 805 | fn ty_inner<'a>(wrapper_names: &[&str], ty: &'a syn::Type) -> Option<&'a syn::Type> { |
| 806 | if let syn::Type::Path(path) = ty { |
| 807 | if path.qself.is_some() { |
| 808 | return None; |
| 809 | } |
| 810 | // Since we only check the last path segment, it isn't necessarily the case that |
| 811 | // we're referring to `std::vec::Vec` or `std::option::Option`, but there isn't |
| 812 | // a fool proof way to check these since name resolution happens after macro expansion, |
| 813 | // so this is likely "good enough" (so long as people don't have their own types called |
| 814 | // `Option` or `Vec` that take one generic parameter they're looking to parse). |
| 815 | let last_segment = path.path.segments.last()?; |
| 816 | if !wrapper_names.iter().any(|name| last_segment.ident == *name) { |
| 817 | return None; |
| 818 | } |
| 819 | if let syn::PathArguments::AngleBracketed(gen_args) = &last_segment.arguments { |
| 820 | let generic_arg = gen_args.args.first()?; |
| 821 | if let syn::GenericArgument::Type(ty) = &generic_arg { |
| 822 | return Some(ty); |
| 823 | } |
| 824 | } |
| 825 | } |
| 826 | None |
| 827 | } |
| 828 | |
| 829 | /// Implements `FromArgs` and `SubCommands` for a `#![derive(FromArgs)]` enum. |
| 830 | fn impl_from_args_enum( |
| 831 | errors: &Errors, |
| 832 | name: &syn::Ident, |
| 833 | type_attrs: &TypeAttrs, |
| 834 | de: &syn::DataEnum, |
| 835 | ) -> TokenStream { |
| 836 | parse_attrs::check_enum_type_attrs(errors, type_attrs, &de.enum_token.span); |
| 837 | |
| 838 | // An enum variant like `<name>(<ty>)` |
| 839 | struct SubCommandVariant<'a> { |
| 840 | name: &'a syn::Ident, |
| 841 | ty: &'a syn::Type, |
| 842 | } |
| 843 | |
| 844 | let variants: Vec<SubCommandVariant<'_>> = de |
| 845 | .variants |
| 846 | .iter() |
| 847 | .filter_map(|variant| { |
| 848 | parse_attrs::check_enum_variant_attrs(errors, variant); |
| 849 | let name = &variant.ident; |
| 850 | let ty = enum_only_single_field_unnamed_variants(errors, &variant.fields)?; |
| 851 | Some(SubCommandVariant { name, ty }) |
| 852 | }) |
| 853 | .collect(); |
| 854 | |
| 855 | let name_repeating = std::iter::repeat(name.clone()); |
| 856 | let variant_ty = variants.iter().map(|x| x.ty).collect::<Vec<_>>(); |
| 857 | let variant_names = variants.iter().map(|x| x.name).collect::<Vec<_>>(); |
| 858 | |
| 859 | quote! { |
| 860 | impl argh::FromArgs for #name { |
| 861 | fn from_args(command_name: &[&str], args: &[&str]) |
| 862 | -> std::result::Result<Self, argh::EarlyExit> |
| 863 | { |
| 864 | let subcommand_name = *command_name.last().expect("no subcommand name"); |
| 865 | #( |
| 866 | if subcommand_name == <#variant_ty as argh::SubCommand>::COMMAND.name { |
| 867 | return Ok(#name_repeating::#variant_names( |
| 868 | <#variant_ty as argh::FromArgs>::from_args(command_name, args)? |
| 869 | )); |
| 870 | } |
| 871 | )* |
| 872 | unreachable!("no subcommand matched") |
| 873 | } |
| 874 | |
| 875 | fn redact_arg_values(command_name: &[&str], args: &[&str]) -> std::result::Result<Vec<String>, argh::EarlyExit> { |
| 876 | let subcommand_name = *command_name.last().expect("no subcommand name"); |
| 877 | #( |
| 878 | if subcommand_name == <#variant_ty as argh::SubCommand>::COMMAND.name { |
| 879 | return <#variant_ty as argh::FromArgs>::redact_arg_values(command_name, args); |
| 880 | } |
| 881 | )* |
| 882 | unreachable!("no subcommand matched") |
| 883 | } |
| 884 | } |
| 885 | |
| 886 | impl argh::SubCommands for #name { |
| 887 | const COMMANDS: &'static [&'static argh::CommandInfo] = &[#( |
| 888 | <#variant_ty as argh::SubCommand>::COMMAND, |
| 889 | )*]; |
| 890 | } |
| 891 | } |
| 892 | } |
| 893 | |
| 894 | /// Returns `Some(Bar)` if the field is a single-field unnamed variant like `Foo(Bar)`. |
| 895 | /// Otherwise, generates an error. |
| 896 | fn enum_only_single_field_unnamed_variants<'a>( |
| 897 | errors: &Errors, |
| 898 | variant_fields: &'a syn::Fields, |
| 899 | ) -> Option<&'a syn::Type> { |
| 900 | macro_rules! with_enum_suggestion { |
| 901 | ($help_text:literal) => { |
| 902 | concat!( |
| 903 | $help_text, |
| 904 | "\nInstead, use a variant with a single unnamed field for each subcommand:\n", |
| 905 | " enum MyCommandEnum {\n", |
| 906 | " SubCommandOne(SubCommandOne),\n", |
| 907 | " SubCommandTwo(SubCommandTwo),\n", |
| 908 | " }", |
| 909 | ) |
| 910 | }; |
| 911 | } |
| 912 | |
| 913 | match variant_fields { |
| 914 | syn::Fields::Named(fields) => { |
| 915 | errors.err( |
| 916 | fields, |
| 917 | with_enum_suggestion!( |
| 918 | "`#![derive(FromArgs)]` `enum`s do not support variants with named fields." |
| 919 | ), |
| 920 | ); |
| 921 | None |
| 922 | } |
| 923 | syn::Fields::Unit => { |
| 924 | errors.err( |
| 925 | variant_fields, |
| 926 | with_enum_suggestion!( |
| 927 | "`#![derive(FromArgs)]` does not support `enum`s with no variants." |
| 928 | ), |
| 929 | ); |
| 930 | None |
| 931 | } |
| 932 | syn::Fields::Unnamed(fields) => { |
| 933 | if fields.unnamed.len() != 1 { |
| 934 | errors.err( |
| 935 | fields, |
| 936 | with_enum_suggestion!( |
| 937 | "`#![derive(FromArgs)]` `enum` variants must only contain one field." |
| 938 | ), |
| 939 | ); |
| 940 | None |
| 941 | } else { |
| 942 | // `unwrap` is okay because of the length check above. |
| 943 | let first_field = fields.unnamed.first().unwrap(); |
| 944 | Some(&first_field.ty) |
| 945 | } |
| 946 | } |
| 947 | } |
| 948 | } |