src/librustc_parse/parser/module.rs

   1 use super::Parser;
   2 use super::item::ItemInfo;
   3 use super::diagnostics::Error;
   4
   5 use crate::{new_sub_parser_from_file, DirectoryOwnership};
   6
   7 use rustc_errors::PResult;
   8 use syntax::attr;
   9 use syntax::ast::{self, Ident, Attribute, ItemKind, Mod, Crate};
  10 use syntax::token::{self, TokenKind};
  11 use syntax_pos::source_map::{SourceMap, Span, DUMMY_SP, FileName};
  12 use syntax_pos::symbol::sym;
  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) = crate::config::process_configure_mod(
  43             self.sess,
  44             self.cfg_mods,
  45             outer_attrs,
  46         );
  47
  48         let id_span = self.token.span;
  49         let id = self.parse_ident()?;
  50         if self.eat(&token::Semi) {
  51             if in_cfg && self.recurse_into_file_modules {
  52                 // This mod is in an external file. Let's go get it!
  53                 let ModulePathSuccess { path, directory_ownership } =
  54                     self.submod_path(id, &outer_attrs, id_span)?;
  55                 let (module, attrs) =
  56                     self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
  57                 Ok((id, ItemKind::Mod(module), Some(attrs)))
  58             } else {
  59                 let placeholder = ast::Mod {
  60                     inner: DUMMY_SP,
  61                     items: Vec::new(),
  62                     inline: false
  63                 };
  64                 Ok((id, ItemKind::Mod(placeholder), None))
  65             }
  66         } else {
  67             let old_directory = self.directory.clone();
  68             self.push_directory(id, &outer_attrs);
  69
  70             self.expect(&token::OpenDelim(token::Brace))?;
  71             let mod_inner_lo = self.token.span;
  72             let attrs = self.parse_inner_attributes()?;
  73             let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;
  74
  75             self.directory = old_directory;
  76             Ok((id, ItemKind::Mod(module), Some(attrs)))
  77         }
  78     }
  79
  80     /// Given a termination token, parses all of the items in a module.
  81     fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> {
  82         let mut items = vec![];
  83         while let Some(item) = self.parse_item()? {
  84             items.push(item);
  85             self.maybe_consume_incorrect_semicolon(&items);
  86         }
  87
  88         if !self.eat(term) {
  89             let token_str = self.this_token_descr();
  90             if !self.maybe_consume_incorrect_semicolon(&items) {
  91                 let mut err = self.fatal(&format!("expected item, found {}", token_str));
  92                 err.span_label(self.token.span, "expected item");
  93                 return Err(err);
  94             }
  95         }
  96
  97         let hi = if self.token.span.is_dummy() {
  98             inner_lo
  99         } else {
 100             self.prev_span
 101         };
 102
 103         Ok(Mod {
 104             inner: inner_lo.to(hi),
 105             items,
 106             inline: true
 107         })
 108     }
 109
 110     fn submod_path(
 111         &mut self,
 112         id: ast::Ident,
 113         outer_attrs: &[Attribute],
 114         id_sp: Span
 115     ) -> PResult<'a, ModulePathSuccess> {
 116         if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
 117             return Ok(ModulePathSuccess {
 118                 directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
 119                     // All `#[path]` files are treated as though they are a `mod.rs` file.
 120                     // This means that `mod foo;` declarations inside `#[path]`-included
 121                     // files are siblings,
 122                     //
 123                     // Note that this will produce weirdness when a file named `foo.rs` is
 124                     // `#[path]` included and contains a `mod foo;` declaration.
 125                     // If you encounter this, it's your own darn fault :P
 126                     Some(_) => DirectoryOwnership::Owned { relative: None },
 127                     _ => DirectoryOwnership::UnownedViaMod,
 128                 },
 129                 path,
 130             });
 131         }
 132
 133         let relative = match self.directory.ownership {
 134             DirectoryOwnership::Owned { relative } => relative,
 135             DirectoryOwnership::UnownedViaBlock |
 136             DirectoryOwnership::UnownedViaMod => None,
 137         };
 138         let paths = Parser::default_submod_path(
 139                         id, relative, &self.directory.path, self.sess.source_map());
 140
 141         match self.directory.ownership {
 142             DirectoryOwnership::Owned { .. } => {
 143                 paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
 144             },
 145             DirectoryOwnership::UnownedViaBlock => {
 146                 let msg =
 147                     "Cannot declare a non-inline module inside a block \
 148                     unless it has a path attribute";
 149                 let mut err = self.diagnostic().struct_span_err(id_sp, msg);
 150                 if paths.path_exists {
 151                     let msg = format!("Maybe `use` the module `{}` instead of redeclaring it",
 152                                       paths.name);
 153                     err.span_note(id_sp, &msg);
 154                 }
 155                 Err(err)
 156             }
 157             DirectoryOwnership::UnownedViaMod => {
 158                 let mut err = self.diagnostic().struct_span_err(id_sp,
 159                     "cannot declare a new module at this location");
 160                 if !id_sp.is_dummy() {
 161                     let src_path = self.sess.source_map().span_to_filename(id_sp);
 162                     if let FileName::Real(src_path) = src_path {
 163                         if let Some(stem) = src_path.file_stem() {
 164                             let mut dest_path = src_path.clone();
 165                             dest_path.set_file_name(stem);
 166                             dest_path.push("mod.rs");
 167                             err.span_note(id_sp,
 168                                     &format!("maybe move this module `{}` to its own \
 169                                                 directory via `{}`", src_path.display(),
 170                                             dest_path.display()));
 171                         }
 172                     }
 173                 }
 174                 if paths.path_exists {
 175                     err.span_note(id_sp,
 176                                   &format!("... or maybe `use` the module `{}` instead \
 177                                             of possibly redeclaring it",
 178                                            paths.name));
 179                 }
 180                 Err(err)
 181             }
 182         }
 183     }
 184
 185     pub(super) fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
 186         if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) {
 187             let s = s.as_str();
 188
 189             // On windows, the base path might have the form
 190             // `\\?\foo\bar` in which case it does not tolerate
 191             // mixed `/` and `\` separators, so canonicalize
 192             // `/` to `\`.
 193             #[cfg(windows)]
 194             let s = s.replace("/", "\\");
 195             Some(dir_path.join(&*s))
 196         } else {
 197             None
 198         }
 199     }
 200
 201     /// Returns a path to a module.
 202     pub(super) fn default_submod_path(
 203         id: ast::Ident,
 204         relative: Option<ast::Ident>,
 205         dir_path: &Path,
 206         source_map: &SourceMap) -> ModulePath
 207     {
 208         // If we're in a foo.rs file instead of a mod.rs file,
 209         // we need to look for submodules in
 210         // `./foo/<id>.rs` and `./foo/<id>/mod.rs` rather than
 211         // `./<id>.rs` and `./<id>/mod.rs`.
 212         let relative_prefix_string;
 213         let relative_prefix = if let Some(ident) = relative {
 214             relative_prefix_string = format!("{}{}", ident.name, path::MAIN_SEPARATOR);
 215             &relative_prefix_string
 216         } else {
 217             ""
 218         };
 219
 220         let mod_name = id.name.to_string();
 221         let default_path_str = format!("{}{}.rs", relative_prefix, mod_name);
 222         let secondary_path_str = format!("{}{}{}mod.rs",
 223                                          relative_prefix, mod_name, path::MAIN_SEPARATOR);
 224         let default_path = dir_path.join(&default_path_str);
 225         let secondary_path = dir_path.join(&secondary_path_str);
 226         let default_exists = source_map.file_exists(&default_path);
 227         let secondary_exists = source_map.file_exists(&secondary_path);
 228
 229         let result = match (default_exists, secondary_exists) {
 230             (true, false) => Ok(ModulePathSuccess {
 231                 path: default_path,
 232                 directory_ownership: DirectoryOwnership::Owned {
 233                     relative: Some(id),
 234                 },
 235             }),
 236             (false, true) => Ok(ModulePathSuccess {
 237                 path: secondary_path,
 238                 directory_ownership: DirectoryOwnership::Owned {
 239                     relative: None,
 240                 },
 241             }),
 242             (false, false) => Err(Error::FileNotFoundForModule {
 243                 mod_name: mod_name.clone(),
 244                 default_path: default_path_str,
 245                 secondary_path: secondary_path_str,
 246                 dir_path: dir_path.display().to_string(),
 247             }),
 248             (true, true) => Err(Error::DuplicatePaths {
 249                 mod_name: mod_name.clone(),
 250                 default_path: default_path_str,
 251                 secondary_path: secondary_path_str,
 252             }),
 253         };
 254
 255         ModulePath {
 256             name: mod_name,
 257             path_exists: default_exists || secondary_exists,
 258             result,
 259         }
 260     }
 261
 262     /// Reads a module from a source file.
 263     fn eval_src_mod(
 264         &mut self,
 265         path: PathBuf,
 266         directory_ownership: DirectoryOwnership,
 267         name: String,
 268         id_sp: Span,
 269     ) -> PResult<'a, (Mod, Vec<Attribute>)> {
 270         let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
 271         if let Some(i) = included_mod_stack.iter().position(|p| *p == path) {
 272             let mut err = String::from("circular modules: ");
 273             let len = included_mod_stack.len();
 274             for p in &included_mod_stack[i.. len] {
 275                 err.push_str(&p.to_string_lossy());
 276                 err.push_str(" -> ");
 277             }
 278             err.push_str(&path.to_string_lossy());
 279             return Err(self.span_fatal(id_sp, &err[..]));
 280         }
 281         included_mod_stack.push(path.clone());
 282         drop(included_mod_stack);
 283
 284         let mut p0 =
 285             new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp);
 286         p0.cfg_mods = self.cfg_mods;
 287         let mod_inner_lo = p0.token.span;
 288         let mod_attrs = p0.parse_inner_attributes()?;
 289         let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
 290         m0.inline = false;
 291         self.sess.included_mod_stack.borrow_mut().pop();
 292         Ok((m0, mod_attrs))
 293     }
 294
 295     fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
 296         if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) {
 297             self.directory.path.to_mut().push(&*path.as_str());
 298             self.directory.ownership = DirectoryOwnership::Owned { relative: None };
 299         } else {
 300             // We have to push on the current module name in the case of relative
 301             // paths in order to ensure that any additional module paths from inline
 302             // `mod x { ... }` come after the relative extension.
 303             //
 304             // For example, a `mod z { ... }` inside `x/y.rs` should set the current
 305             // directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
 306             if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
 307                 if let Some(ident) = relative.take() { // remove the relative offset
 308                     self.directory.path.to_mut().push(&*ident.as_str());
 309                 }
 310             }
 311             self.directory.path.to_mut().push(&*id.as_str());
 312         }
 313     }
 314 }