src/librustc_parse/parser/module.rs

   1 use super::diagnostics::Error;
   2 use super::item::ItemInfo;
   3 use super::Parser;
   4
   5 use crate::{new_sub_parser_from_file, DirectoryOwnership};
   6
   7 use rustc_errors::PResult;
   8 use rustc_span::source_map::{FileName, SourceMap, Span, DUMMY_SP};
   9 use rustc_span::symbol::sym;
  10 use syntax::ast::{self, Attribute, Crate, Ident, ItemKind, Mod};
  11 use syntax::attr;
  12 use syntax::token::{self, TokenKind};
  13
  14 use std::path::{self, Path, PathBuf};
  15
  16 /// Information about the path to a module.
  17 pub(super) struct ModulePath {
  18     name: String,
  19     path_exists: bool,
  20     pub result: Result<ModulePathSuccess, Error>,
  21 }
  22
  23 pub(super) struct ModulePathSuccess {
  24     pub path: PathBuf,
  25     pub directory_ownership: DirectoryOwnership,
  26 }
  27
  28 impl<'a> Parser<'a> {
  29     /// Parses a source module as a crate. This is the main entry point for the parser.
  30     pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
  31         let lo = self.token.span;
  32         let krate = Ok(ast::Crate {
  33             attrs: self.parse_inner_attributes()?,
  34             module: self.parse_mod_items(&token::Eof, lo)?,
  35             span: lo.to(self.token.span),
  36         });
  37         krate
  38     }
  39
  40     /// Parses a `mod <foo> { ... }` or `mod <foo>;` item.
  41     pub(super) fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
  42         let (in_cfg, outer_attrs) =
  43             crate::config::process_configure_mod(self.sess, self.cfg_mods, outer_attrs);
  44
  45         let id_span = self.token.span;
  46         let id = self.parse_ident()?;
  47         if self.eat(&token::Semi) {
  48             if in_cfg && self.recurse_into_file_modules {
  49                 // This mod is in an external file. Let's go get it!
  50                 let ModulePathSuccess { path, directory_ownership } =
  51                     self.submod_path(id, &outer_attrs, id_span)?;
  52                 let (module, attrs) =
  53                     self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
  54                 Ok((id, ItemKind::Mod(module), Some(attrs)))
  55             } else {
  56                 let placeholder = ast::Mod { inner: DUMMY_SP, items: Vec::new(), inline: false };
  57                 Ok((id, ItemKind::Mod(placeholder), None))
  58             }
  59         } else {
  60             let old_directory = self.directory.clone();
  61             self.push_directory(id, &outer_attrs);
  62
  63             self.expect(&token::OpenDelim(token::Brace))?;
  64             let mod_inner_lo = self.token.span;
  65             let attrs = self.parse_inner_attributes()?;
  66             let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;
  67
  68             self.directory = old_directory;
  69             Ok((id, ItemKind::Mod(module), Some(attrs)))
  70         }
  71     }
  72
  73     /// Given a termination token, parses all of the items in a module.
  74     fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> {
  75         let mut items = vec![];
  76         while let Some(item) = self.parse_item()? {
  77             items.push(item);
  78             self.maybe_consume_incorrect_semicolon(&items);
  79         }
  80
  81         if !self.eat(term) {
  82             let token_str = super::token_descr(&self.token);
  83             if !self.maybe_consume_incorrect_semicolon(&items) {
  84                 let msg = &format!("expected item, found {}", token_str);
  85                 let mut err = self.struct_span_err(self.token.span, msg);
  86                 err.span_label(self.token.span, "expected item");
  87                 return Err(err);
  88             }
  89         }
  90
  91         let hi = if self.token.span.is_dummy() { inner_lo } else { self.prev_span };
  92
  93         Ok(Mod { inner: inner_lo.to(hi), items, inline: true })
  94     }
  95
  96     fn submod_path(
  97         &mut self,
  98         id: ast::Ident,
  99         outer_attrs: &[Attribute],
 100         id_sp: Span,
 101     ) -> PResult<'a, ModulePathSuccess> {
 102         if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
 103             return Ok(ModulePathSuccess {
 104                 directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
 105                     // All `#[path]` files are treated as though they are a `mod.rs` file.
 106                     // This means that `mod foo;` declarations inside `#[path]`-included
 107                     // files are siblings,
 108                     //
 109                     // Note that this will produce weirdness when a file named `foo.rs` is
 110                     // `#[path]` included and contains a `mod foo;` declaration.
 111                     // If you encounter this, it's your own darn fault :P
 112                     Some(_) => DirectoryOwnership::Owned { relative: None },
 113                     _ => DirectoryOwnership::UnownedViaMod,
 114                 },
 115                 path,
 116             });
 117         }
 118
 119         let relative = match self.directory.ownership {
 120             DirectoryOwnership::Owned { relative } => relative,
 121             DirectoryOwnership::UnownedViaBlock | DirectoryOwnership::UnownedViaMod => None,
 122         };
 123         let paths =
 124             Parser::default_submod_path(id, relative, &self.directory.path, self.sess.source_map());
 125
 126         match self.directory.ownership {
 127             DirectoryOwnership::Owned { .. } => {
 128                 paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
 129             }
 130             DirectoryOwnership::UnownedViaBlock => {
 131                 let msg = "Cannot declare a non-inline module inside a block \
 132                     unless it has a path attribute";
 133                 let mut err = self.struct_span_err(id_sp, msg);
 134                 if paths.path_exists {
 135                     let msg = format!(
 136                         "Maybe `use` the module `{}` instead of redeclaring it",
 137                         paths.name
 138                     );
 139                     err.span_note(id_sp, &msg);
 140                 }
 141                 Err(err)
 142             }
 143             DirectoryOwnership::UnownedViaMod => {
 144                 let mut err =
 145                     self.struct_span_err(id_sp, "cannot declare a new module at this location");
 146                 if !id_sp.is_dummy() {
 147                     let src_path = self.sess.source_map().span_to_filename(id_sp);
 148                     if let FileName::Real(src_path) = src_path {
 149                         if let Some(stem) = src_path.file_stem() {
 150                             let mut dest_path = src_path.clone();
 151                             dest_path.set_file_name(stem);
 152                             dest_path.push("mod.rs");
 153                             err.span_note(
 154                                 id_sp,
 155                                 &format!(
 156                                     "maybe move this module `{}` to its own \
 157                                                 directory via `{}`",
 158                                     src_path.display(),
 159                                     dest_path.display()
 160                                 ),
 161                             );
 162                         }
 163                     }
 164                 }
 165                 if paths.path_exists {
 166                     err.span_note(
 167                         id_sp,
 168                         &format!(
 169                             "... or maybe `use` the module `{}` instead \
 170                                             of possibly redeclaring it",
 171                             paths.name
 172                         ),
 173                     );
 174                 }
 175                 Err(err)
 176             }
 177         }
 178     }
 179
 180     pub(super) fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
 181         if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) {
 182             let s = s.as_str();
 183
 184             // On windows, the base path might have the form
 185             // `\\?\foo\bar` in which case it does not tolerate
 186             // mixed `/` and `\` separators, so canonicalize
 187             // `/` to `\`.
 188             #[cfg(windows)]
 189             let s = s.replace("/", "\\");
 190             Some(dir_path.join(&*s))
 191         } else {
 192             None
 193         }
 194     }
 195
 196     /// Returns a path to a module.
 197     pub(super) fn default_submod_path(
 198         id: ast::Ident,
 199         relative: Option<ast::Ident>,
 200         dir_path: &Path,
 201         source_map: &SourceMap,
 202     ) -> ModulePath {
 203         // If we're in a foo.rs file instead of a mod.rs file,
 204         // we need to look for submodules in
 205         // `./foo/<id>.rs` and `./foo/<id>/mod.rs` rather than
 206         // `./<id>.rs` and `./<id>/mod.rs`.
 207         let relative_prefix_string;
 208         let relative_prefix = if let Some(ident) = relative {
 209             relative_prefix_string = format!("{}{}", ident.name, path::MAIN_SEPARATOR);
 210             &relative_prefix_string
 211         } else {
 212             ""
 213         };
 214
 215         let mod_name = id.name.to_string();
 216         let default_path_str = format!("{}{}.rs", relative_prefix, mod_name);
 217         let secondary_path_str =
 218             format!("{}{}{}mod.rs", relative_prefix, mod_name, path::MAIN_SEPARATOR);
 219         let default_path = dir_path.join(&default_path_str);
 220         let secondary_path = dir_path.join(&secondary_path_str);
 221         let default_exists = source_map.file_exists(&default_path);
 222         let secondary_exists = source_map.file_exists(&secondary_path);
 223
 224         let result = match (default_exists, secondary_exists) {
 225             (true, false) => Ok(ModulePathSuccess {
 226                 path: default_path,
 227                 directory_ownership: DirectoryOwnership::Owned { relative: Some(id) },
 228             }),
 229             (false, true) => Ok(ModulePathSuccess {
 230                 path: secondary_path,
 231                 directory_ownership: DirectoryOwnership::Owned { relative: None },
 232             }),
 233             (false, false) => Err(Error::FileNotFoundForModule {
 234                 mod_name: mod_name.clone(),
 235                 default_path: default_path_str,
 236                 secondary_path: secondary_path_str,
 237                 dir_path: dir_path.display().to_string(),
 238             }),
 239             (true, true) => Err(Error::DuplicatePaths {
 240                 mod_name: mod_name.clone(),
 241                 default_path: default_path_str,
 242                 secondary_path: secondary_path_str,
 243             }),
 244         };
 245
 246         ModulePath { name: mod_name, path_exists: default_exists || secondary_exists, result }
 247     }
 248
 249     /// Reads a module from a source file.
 250     fn eval_src_mod(
 251         &mut self,
 252         path: PathBuf,
 253         directory_ownership: DirectoryOwnership,
 254         name: String,
 255         id_sp: Span,
 256     ) -> PResult<'a, (Mod, Vec<Attribute>)> {
 257         let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
 258         if let Some(i) = included_mod_stack.iter().position(|p| *p == path) {
 259             let mut err = String::from("circular modules: ");
 260             let len = included_mod_stack.len();
 261             for p in &included_mod_stack[i..len] {
 262                 err.push_str(&p.to_string_lossy());
 263                 err.push_str(" -> ");
 264             }
 265             err.push_str(&path.to_string_lossy());
 266             return Err(self.struct_span_err(id_sp, &err[..]));
 267         }
 268         included_mod_stack.push(path.clone());
 269         drop(included_mod_stack);
 270
 271         let mut p0 =
 272             new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp);
 273         p0.cfg_mods = self.cfg_mods;
 274         let mod_inner_lo = p0.token.span;
 275         let mod_attrs = p0.parse_inner_attributes()?;
 276         let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
 277         m0.inline = false;
 278         self.sess.included_mod_stack.borrow_mut().pop();
 279         Ok((m0, mod_attrs))
 280     }
 281
 282     fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
 283         if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) {
 284             self.directory.path.to_mut().push(&*path.as_str());
 285             self.directory.ownership = DirectoryOwnership::Owned { relative: None };
 286         } else {
 287             // We have to push on the current module name in the case of relative
 288             // paths in order to ensure that any additional module paths from inline
 289             // `mod x { ... }` come after the relative extension.
 290             //
 291             // For example, a `mod z { ... }` inside `x/y.rs` should set the current
 292             // directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
 293             if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
 294                 if let Some(ident) = relative.take() {
 295                     // remove the relative offset
 296                     self.directory.path.to_mut().push(&*ident.as_str());
 297                 }
 298             }
 299             self.directory.path.to_mut().push(&*id.as_str());
 300         }
 301     }
 302 }