src/tools/rustfmt/src/modules.rs

   1 use std::borrow::Cow;
   2 use std::collections::BTreeMap;
   3 use std::path::{Path, PathBuf};
   4
   5 use rustc_ast::ast;
   6 use rustc_ast::visit::Visitor;
   7 use rustc_ast::AstLike;
   8 use rustc_span::symbol::{self, sym, Symbol};
   9 use rustc_span::Span;
  10 use thiserror::Error;
  11
  12 use crate::attr::MetaVisitor;
  13 use crate::config::FileName;
  14 use crate::items::is_mod_decl;
  15 use crate::parse::parser::{
  16     Directory, DirectoryOwnership, ModError, ModulePathSuccess, Parser, ParserError,
  17 };
  18 use crate::parse::session::ParseSess;
  19 use crate::utils::{contains_skip, mk_sp};
  20
  21 mod visitor;
  22
  23 type FileModMap<'ast> = BTreeMap<FileName, Module<'ast>>;
  24
  25 /// Represents module with its inner attributes.
  26 #[derive(Debug, Clone)]
  27 pub(crate) struct Module<'a> {
  28     ast_mod_kind: Option<Cow<'a, ast::ModKind>>,
  29     pub(crate) items: Cow<'a, Vec<rustc_ast::ptr::P<ast::Item>>>,
  30     inner_attr: Vec<ast::Attribute>,
  31     pub(crate) span: Span,
  32 }
  33
  34 impl<'a> Module<'a> {
  35     pub(crate) fn new(
  36         mod_span: Span,
  37         ast_mod_kind: Option<Cow<'a, ast::ModKind>>,
  38         mod_items: Cow<'a, Vec<rustc_ast::ptr::P<ast::Item>>>,
  39         mod_attrs: Cow<'a, Vec<ast::Attribute>>,
  40     ) -> Self {
  41         let inner_attr = mod_attrs
  42             .iter()
  43             .filter(|attr| attr.style == ast::AttrStyle::Inner)
  44             .cloned()
  45             .collect();
  46         Module {
  47             items: mod_items,
  48             inner_attr,
  49             span: mod_span,
  50             ast_mod_kind,
  51         }
  52     }
  53 }
  54
  55 impl<'a> AstLike for Module<'a> {
  56     const SUPPORTS_CUSTOM_INNER_ATTRS: bool = true;
  57     fn attrs(&self) -> &[ast::Attribute] {
  58         &self.inner_attr
  59     }
  60     fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<ast::Attribute>)) {
  61         f(&mut self.inner_attr)
  62     }
  63     fn tokens_mut(&mut self) -> Option<&mut Option<rustc_ast::tokenstream::LazyTokenStream>> {
  64         unimplemented!()
  65     }
  66 }
  67
  68 /// Maps each module to the corresponding file.
  69 pub(crate) struct ModResolver<'ast, 'sess> {
  70     parse_sess: &'sess ParseSess,
  71     directory: Directory,
  72     file_map: FileModMap<'ast>,
  73     recursive: bool,
  74 }
  75
  76 /// Represents errors while trying to resolve modules.
  77 #[derive(Debug, Error)]
  78 #[error("failed to resolve mod `{module}`: {kind}")]
  79 pub struct ModuleResolutionError {
  80     pub(crate) module: String,
  81     pub(crate) kind: ModuleResolutionErrorKind,
  82 }
  83
  84 #[derive(Debug, Error)]
  85 pub(crate) enum ModuleResolutionErrorKind {
  86     /// Find a file that cannot be parsed.
  87     #[error("cannot parse {file}")]
  88     ParseError { file: PathBuf },
  89     /// File cannot be found.
  90     #[error("{file} does not exist")]
  91     NotFound { file: PathBuf },
  92 }
  93
  94 #[derive(Clone)]
  95 enum SubModKind<'a, 'ast> {
  96     /// `mod foo;`
  97     External(PathBuf, DirectoryOwnership, Module<'ast>),
  98     /// `mod foo;` with multiple sources.
  99     MultiExternal(Vec<(PathBuf, DirectoryOwnership, Module<'ast>)>),
 100     /// `mod foo {}`
 101     Internal(&'a ast::Item),
 102 }
 103
 104 impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
 105     /// Creates a new `ModResolver`.
 106     pub(crate) fn new(
 107         parse_sess: &'sess ParseSess,
 108         directory_ownership: DirectoryOwnership,
 109         recursive: bool,
 110     ) -> Self {
 111         ModResolver {
 112             directory: Directory {
 113                 path: PathBuf::new(),
 114                 ownership: directory_ownership,
 115             },
 116             file_map: BTreeMap::new(),
 117             parse_sess,
 118             recursive,
 119         }
 120     }
 121
 122     /// Creates a map that maps a file name to the module in AST.
 123     pub(crate) fn visit_crate(
 124         mut self,
 125         krate: &'ast ast::Crate,
 126     ) -> Result<FileModMap<'ast>, ModuleResolutionError> {
 127         let root_filename = self.parse_sess.span_to_filename(krate.span);
 128         self.directory.path = match root_filename {
 129             FileName::Real(ref p) => p.parent().unwrap_or(Path::new("")).to_path_buf(),
 130             _ => PathBuf::new(),
 131         };
 132
 133         // Skip visiting sub modules when the input is from stdin.
 134         if self.recursive {
 135             self.visit_mod_from_ast(&krate.items)?;
 136         }
 137
 138         let snippet_provider = self.parse_sess.snippet_provider(krate.span);
 139
 140         self.file_map.insert(
 141             root_filename,
 142             Module::new(
 143                 mk_sp(snippet_provider.start_pos(), snippet_provider.end_pos()),
 144                 None,
 145                 Cow::Borrowed(&krate.items),
 146                 Cow::Borrowed(&krate.attrs),
 147             ),
 148         );
 149         Ok(self.file_map)
 150     }
 151
 152     /// Visit `cfg_if` macro and look for module declarations.
 153     fn visit_cfg_if(&mut self, item: Cow<'ast, ast::Item>) -> Result<(), ModuleResolutionError> {
 154         let mut visitor = visitor::CfgIfVisitor::new(self.parse_sess);
 155         visitor.visit_item(&item);
 156         for module_item in visitor.mods() {
 157             if let ast::ItemKind::Mod(_, ref sub_mod_kind) = module_item.item.kind {
 158                 self.visit_sub_mod(
 159                     &module_item.item,
 160                     Module::new(
 161                         module_item.item.span,
 162                         Some(Cow::Owned(sub_mod_kind.clone())),
 163                         Cow::Owned(vec![]),
 164                         Cow::Owned(vec![]),
 165                     ),
 166                 )?;
 167             }
 168         }
 169         Ok(())
 170     }
 171
 172     /// Visit modules defined inside macro calls.
 173     fn visit_mod_outside_ast(
 174         &mut self,
 175         items: Vec<rustc_ast::ptr::P<ast::Item>>,
 176     ) -> Result<(), ModuleResolutionError> {
 177         for item in items {
 178             if is_cfg_if(&item) {
 179                 self.visit_cfg_if(Cow::Owned(item.into_inner()))?;
 180                 continue;
 181             }
 182
 183             if let ast::ItemKind::Mod(_, ref sub_mod_kind) = item.kind {
 184                 let span = item.span;
 185                 self.visit_sub_mod(
 186                     &item,
 187                     Module::new(
 188                         span,
 189                         Some(Cow::Owned(sub_mod_kind.clone())),
 190                         Cow::Owned(vec![]),
 191                         Cow::Owned(vec![]),
 192                     ),
 193                 )?;
 194             }
 195         }
 196         Ok(())
 197     }
 198
 199     /// Visit modules from AST.
 200     fn visit_mod_from_ast(
 201         &mut self,
 202         items: &'ast [rustc_ast::ptr::P<ast::Item>],
 203     ) -> Result<(), ModuleResolutionError> {
 204         for item in items {
 205             if is_cfg_if(item) {
 206                 self.visit_cfg_if(Cow::Borrowed(item))?;
 207             }
 208
 209             if let ast::ItemKind::Mod(_, ref sub_mod_kind) = item.kind {
 210                 let span = item.span;
 211                 self.visit_sub_mod(
 212                     item,
 213                     Module::new(
 214                         span,
 215                         Some(Cow::Borrowed(sub_mod_kind)),
 216                         Cow::Owned(vec![]),
 217                         Cow::Borrowed(&item.attrs),
 218                     ),
 219                 )?;
 220             }
 221         }
 222         Ok(())
 223     }
 224
 225     fn visit_sub_mod(
 226         &mut self,
 227         item: &'c ast::Item,
 228         sub_mod: Module<'ast>,
 229     ) -> Result<(), ModuleResolutionError> {
 230         let old_directory = self.directory.clone();
 231         let sub_mod_kind = self.peek_sub_mod(item, &sub_mod)?;
 232         if let Some(sub_mod_kind) = sub_mod_kind {
 233             self.insert_sub_mod(sub_mod_kind.clone())?;
 234             self.visit_sub_mod_inner(sub_mod, sub_mod_kind)?;
 235         }
 236         self.directory = old_directory;
 237         Ok(())
 238     }
 239
 240     /// Inspect the given sub-module which we are about to visit and returns its kind.
 241     fn peek_sub_mod(
 242         &self,
 243         item: &'c ast::Item,
 244         sub_mod: &Module<'ast>,
 245     ) -> Result<Option<SubModKind<'c, 'ast>>, ModuleResolutionError> {
 246         if contains_skip(&item.attrs) {
 247             return Ok(None);
 248         }
 249
 250         if is_mod_decl(item) {
 251             // mod foo;
 252             // Look for an extern file.
 253             self.find_external_module(item.ident, &item.attrs, sub_mod)
 254         } else {
 255             // An internal module (`mod foo { /* ... */ }`);
 256             Ok(Some(SubModKind::Internal(item)))
 257         }
 258     }
 259
 260     fn insert_sub_mod(
 261         &mut self,
 262         sub_mod_kind: SubModKind<'c, 'ast>,
 263     ) -> Result<(), ModuleResolutionError> {
 264         match sub_mod_kind {
 265             SubModKind::External(mod_path, _, sub_mod) => {
 266                 self.file_map
 267                     .entry(FileName::Real(mod_path))
 268                     .or_insert(sub_mod);
 269             }
 270             SubModKind::MultiExternal(mods) => {
 271                 for (mod_path, _, sub_mod) in mods {
 272                     self.file_map
 273                         .entry(FileName::Real(mod_path))
 274                         .or_insert(sub_mod);
 275                 }
 276             }
 277             _ => (),
 278         }
 279         Ok(())
 280     }
 281
 282     fn visit_sub_mod_inner(
 283         &mut self,
 284         sub_mod: Module<'ast>,
 285         sub_mod_kind: SubModKind<'c, 'ast>,
 286     ) -> Result<(), ModuleResolutionError> {
 287         match sub_mod_kind {
 288             SubModKind::External(mod_path, directory_ownership, sub_mod) => {
 289                 let directory = Directory {
 290                     path: mod_path.parent().unwrap().to_path_buf(),
 291                     ownership: directory_ownership,
 292                 };
 293                 self.visit_sub_mod_after_directory_update(sub_mod, Some(directory))
 294             }
 295             SubModKind::Internal(item) => {
 296                 self.push_inline_mod_directory(item.ident, &item.attrs);
 297                 self.visit_sub_mod_after_directory_update(sub_mod, None)
 298             }
 299             SubModKind::MultiExternal(mods) => {
 300                 for (mod_path, directory_ownership, sub_mod) in mods {
 301                     let directory = Directory {
 302                         path: mod_path.parent().unwrap().to_path_buf(),
 303                         ownership: directory_ownership,
 304                     };
 305                     self.visit_sub_mod_after_directory_update(sub_mod, Some(directory))?;
 306                 }
 307                 Ok(())
 308             }
 309         }
 310     }
 311
 312     fn visit_sub_mod_after_directory_update(
 313         &mut self,
 314         sub_mod: Module<'ast>,
 315         directory: Option<Directory>,
 316     ) -> Result<(), ModuleResolutionError> {
 317         if let Some(directory) = directory {
 318             self.directory = directory;
 319         }
 320         match (sub_mod.ast_mod_kind, sub_mod.items) {
 321             (Some(Cow::Borrowed(ast::ModKind::Loaded(items, _, _))), _) => {
 322                 self.visit_mod_from_ast(items)
 323             }
 324             (Some(Cow::Owned(ast::ModKind::Loaded(items, _, _))), _) | (_, Cow::Owned(items)) => {
 325                 self.visit_mod_outside_ast(items)
 326             }
 327             (_, _) => Ok(()),
 328         }
 329     }
 330
 331     /// Find a file path in the filesystem which corresponds to the given module.
 332     fn find_external_module(
 333         &self,
 334         mod_name: symbol::Ident,
 335         attrs: &[ast::Attribute],
 336         sub_mod: &Module<'ast>,
 337     ) -> Result<Option<SubModKind<'c, 'ast>>, ModuleResolutionError> {
 338         let relative = match self.directory.ownership {
 339             DirectoryOwnership::Owned { relative } => relative,
 340             DirectoryOwnership::UnownedViaBlock => None,
 341         };
 342         if let Some(path) = Parser::submod_path_from_attr(attrs, &self.directory.path) {
 343             if self.parse_sess.is_file_parsed(&path) {
 344                 return Ok(None);
 345             }
 346             return match Parser::parse_file_as_module(self.parse_sess, &path, sub_mod.span) {
 347                 Ok((ref attrs, _, _)) if contains_skip(attrs) => Ok(None),
 348                 Ok((attrs, items, span)) => Ok(Some(SubModKind::External(
 349                     path,
 350                     DirectoryOwnership::Owned { relative: None },
 351                     Module::new(
 352                         span,
 353                         Some(Cow::Owned(ast::ModKind::Unloaded)),
 354                         Cow::Owned(items),
 355                         Cow::Owned(attrs),
 356                     ),
 357                 ))),
 358                 Err(ParserError::ParseError) => Err(ModuleResolutionError {
 359                     module: mod_name.to_string(),
 360                     kind: ModuleResolutionErrorKind::ParseError { file: path },
 361                 }),
 362                 Err(..) => Err(ModuleResolutionError {
 363                     module: mod_name.to_string(),
 364                     kind: ModuleResolutionErrorKind::NotFound { file: path },
 365                 }),
 366             };
 367         }
 368
 369         // Look for nested path, like `#[cfg_attr(feature = "foo", path = "bar.rs")]`.
 370         let mut mods_outside_ast = self.find_mods_outside_of_ast(attrs, sub_mod);
 371
 372         match self
 373             .parse_sess
 374             .default_submod_path(mod_name, relative, &self.directory.path)
 375         {
 376             Ok(ModulePathSuccess {
 377                 file_path,
 378                 dir_ownership,
 379                 ..
 380             }) => {
 381                 let outside_mods_empty = mods_outside_ast.is_empty();
 382                 let should_insert = !mods_outside_ast
 383                     .iter()
 384                     .any(|(outside_path, _, _)| outside_path == &file_path);
 385                 if self.parse_sess.is_file_parsed(&file_path) {
 386                     if outside_mods_empty {
 387                         return Ok(None);
 388                     } else {
 389                         if should_insert {
 390                             mods_outside_ast.push((file_path, dir_ownership, sub_mod.clone()));
 391                         }
 392                         return Ok(Some(SubModKind::MultiExternal(mods_outside_ast)));
 393                     }
 394                 }
 395                 match Parser::parse_file_as_module(self.parse_sess, &file_path, sub_mod.span) {
 396                     Ok((ref attrs, _, _)) if contains_skip(attrs) => Ok(None),
 397                     Ok((attrs, items, span)) if outside_mods_empty => {
 398                         Ok(Some(SubModKind::External(
 399                             file_path,
 400                             dir_ownership,
 401                             Module::new(
 402                                 span,
 403                                 Some(Cow::Owned(ast::ModKind::Unloaded)),
 404                                 Cow::Owned(items),
 405                                 Cow::Owned(attrs),
 406                             ),
 407                         )))
 408                     }
 409                     Ok((attrs, items, span)) => {
 410                         mods_outside_ast.push((
 411                             file_path.clone(),
 412                             dir_ownership,
 413                             Module::new(
 414                                 span,
 415                                 Some(Cow::Owned(ast::ModKind::Unloaded)),
 416                                 Cow::Owned(items),
 417                                 Cow::Owned(attrs),
 418                             ),
 419                         ));
 420                         if should_insert {
 421                             mods_outside_ast.push((file_path, dir_ownership, sub_mod.clone()));
 422                         }
 423                         Ok(Some(SubModKind::MultiExternal(mods_outside_ast)))
 424                     }
 425                     Err(ParserError::ParseError) => Err(ModuleResolutionError {
 426                         module: mod_name.to_string(),
 427                         kind: ModuleResolutionErrorKind::ParseError { file: file_path },
 428                     }),
 429                     Err(..) if outside_mods_empty => Err(ModuleResolutionError {
 430                         module: mod_name.to_string(),
 431                         kind: ModuleResolutionErrorKind::NotFound { file: file_path },
 432                     }),
 433                     Err(..) => {
 434                         if should_insert {
 435                             mods_outside_ast.push((file_path, dir_ownership, sub_mod.clone()));
 436                         }
 437                         Ok(Some(SubModKind::MultiExternal(mods_outside_ast)))
 438                     }
 439                 }
 440             }
 441             Err(mod_err) if !mods_outside_ast.is_empty() => {
 442                 if let ModError::ParserError(mut e) = mod_err {
 443                     e.cancel();
 444                 }
 445                 Ok(Some(SubModKind::MultiExternal(mods_outside_ast)))
 446             }
 447             Err(_) => Err(ModuleResolutionError {
 448                 module: mod_name.to_string(),
 449                 kind: ModuleResolutionErrorKind::NotFound {
 450                     file: self.directory.path.clone(),
 451                 },
 452             }),
 453         }
 454     }
 455
 456     fn push_inline_mod_directory(&mut self, id: symbol::Ident, attrs: &[ast::Attribute]) {
 457         if let Some(path) = find_path_value(attrs) {
 458             self.directory.path.push(path.as_str());
 459             self.directory.ownership = DirectoryOwnership::Owned { relative: None };
 460         } else {
 461             // We have to push on the current module name in the case of relative
 462             // paths in order to ensure that any additional module paths from inline
 463             // `mod x { ... }` come after the relative extension.
 464             //
 465             // For example, a `mod z { ... }` inside `x/y.rs` should set the current
 466             // directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
 467             if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
 468                 if let Some(ident) = relative.take() {
 469                     // remove the relative offset
 470                     self.directory.path.push(ident.as_str());
 471                 }
 472             }
 473             self.directory.path.push(id.as_str());
 474         }
 475     }
 476
 477     fn find_mods_outside_of_ast(
 478         &self,
 479         attrs: &[ast::Attribute],
 480         sub_mod: &Module<'ast>,
 481     ) -> Vec<(PathBuf, DirectoryOwnership, Module<'ast>)> {
 482         // Filter nested path, like `#[cfg_attr(feature = "foo", path = "bar.rs")]`.
 483         let mut path_visitor = visitor::PathVisitor::default();
 484         for attr in attrs.iter() {
 485             if let Some(meta) = attr.meta() {
 486                 path_visitor.visit_meta_item(&meta)
 487             }
 488         }
 489         let mut result = vec![];
 490         for path in path_visitor.paths() {
 491             let mut actual_path = self.directory.path.clone();
 492             actual_path.push(&path);
 493             if !actual_path.exists() {
 494                 continue;
 495             }
 496             if self.parse_sess.is_file_parsed(&actual_path) {
 497                 // If the specified file is already parsed, then we just use that.
 498                 result.push((
 499                     actual_path,
 500                     DirectoryOwnership::Owned { relative: None },
 501                     sub_mod.clone(),
 502                 ));
 503                 continue;
 504             }
 505             let (attrs, items, span) =
 506                 match Parser::parse_file_as_module(self.parse_sess, &actual_path, sub_mod.span) {
 507                     Ok((ref attrs, _, _)) if contains_skip(attrs) => continue,
 508                     Ok(m) => m,
 509                     Err(..) => continue,
 510                 };
 511
 512             result.push((
 513                 actual_path,
 514                 DirectoryOwnership::Owned { relative: None },
 515                 Module::new(
 516                     span,
 517                     Some(Cow::Owned(ast::ModKind::Unloaded)),
 518                     Cow::Owned(items),
 519                     Cow::Owned(attrs),
 520                 ),
 521             ))
 522         }
 523         result
 524     }
 525 }
 526
 527 fn path_value(attr: &ast::Attribute) -> Option<Symbol> {
 528     if attr.has_name(sym::path) {
 529         attr.value_str()
 530     } else {
 531         None
 532     }
 533 }
 534
 535 // N.B., even when there are multiple `#[path = ...]` attributes, we just need to
 536 // examine the first one, since rustc ignores the second and the subsequent ones
 537 // as unused attributes.
 538 fn find_path_value(attrs: &[ast::Attribute]) -> Option<Symbol> {
 539     attrs.iter().flat_map(path_value).next()
 540 }
 541
 542 fn is_cfg_if(item: &ast::Item) -> bool {
 543     match item.kind {
 544         ast::ItemKind::MacCall(ref mac) => {
 545             if let Some(first_segment) = mac.path.segments.first() {
 546                 if first_segment.ident.name == Symbol::intern("cfg_if") {
 547                     return true;
 548                 }
 549             }
 550             false
 551         }
 552         _ => false,
 553     }
 554 }