summaryrefslogtreecommitdiffstats
path: root/src/librustc_parse/parser/module.rs
blob: 59d7c2b423972c895d4fa1e70cf592286e472e7a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
use super::Parser;
use super::item::ItemInfo;
use super::diagnostics::Error;

use crate::{new_sub_parser_from_file, DirectoryOwnership};

use syntax::attr;
use syntax::ast::{self, Ident, Attribute, ItemKind, Mod, Crate};
use syntax::token::{self, TokenKind};
use syntax::source_map::{SourceMap, Span, DUMMY_SP, FileName};

use syntax_pos::symbol::sym;
use errors::PResult;

use std::path::{self, Path, PathBuf};

/// Information about the path to a module.
pub(super) struct ModulePath {
    name: String,
    path_exists: bool,
    pub result: Result<ModulePathSuccess, Error>,
}

pub(super) struct ModulePathSuccess {
    pub path: PathBuf,
    pub directory_ownership: DirectoryOwnership,
}

impl<'a> Parser<'a> {
    /// Parses a source module as a crate. This is the main entry point for the parser.
    pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
        let lo = self.token.span;
        let krate = Ok(ast::Crate {
            attrs: self.parse_inner_attributes()?,
            module: self.parse_mod_items(&token::Eof, lo)?,
            span: lo.to(self.token.span),
        });
        krate
    }

    /// Parses a `mod <foo> { ... }` or `mod <foo>;` item.
    pub(super) fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
        let (in_cfg, outer_attrs) = crate::config::process_configure_mod(
            self.sess,
            self.cfg_mods,
            outer_attrs,
        );

        let id_span = self.token.span;
        let id = self.parse_ident()?;
        if self.eat(&token::Semi) {
            if in_cfg && self.recurse_into_file_modules {
                // This mod is in an external file. Let's go get it!
                let ModulePathSuccess { path, directory_ownership } =
                    self.submod_path(id, &outer_attrs, id_span)?;
                let (module, attrs) =
                    self.eval_src_mod(path, directory_ownership, id.to_string(), id_span)?;
                Ok((id, ItemKind::Mod(module), Some(attrs)))
            } else {
                let placeholder = ast::Mod {
                    inner: DUMMY_SP,
                    items: Vec::new(),
                    inline: false
                };
                Ok((id, ItemKind::Mod(placeholder), None))
            }
        } else {
            let old_directory = self.directory.clone();
            self.push_directory(id, &outer_attrs);

            self.expect(&token::OpenDelim(token::Brace))?;
            let mod_inner_lo = self.token.span;
            let attrs = self.parse_inner_attributes()?;
            let module = self.parse_mod_items(&token::CloseDelim(token::Brace), mod_inner_lo)?;

            self.directory = old_directory;
            Ok((id, ItemKind::Mod(module), Some(attrs)))
        }
    }

    /// Given a termination token, parses all of the items in a module.
    fn parse_mod_items(&mut self, term: &TokenKind, inner_lo: Span) -> PResult<'a, Mod> {
        let mut items = vec![];
        while let Some(item) = self.parse_item()? {
            items.push(item);
            self.maybe_consume_incorrect_semicolon(&items);
        }

        if !self.eat(term) {
            let token_str = self.this_token_descr();
            if !self.maybe_consume_incorrect_semicolon(&items) {
                let mut err = self.fatal(&format!("expected item, found {}", token_str));
                err.span_label(self.token.span, "expected item");
                return Err(err);
            }
        }

        let hi = if self.token.span.is_dummy() {
            inner_lo
        } else {
            self.prev_span
        };

        Ok(Mod {
            inner: inner_lo.to(hi),
            items,
            inline: true
        })
    }

    fn submod_path(
        &mut self,
        id: ast::Ident,
        outer_attrs: &[Attribute],
        id_sp: Span
    ) -> PResult<'a, ModulePathSuccess> {
        if let Some(path) = Parser::submod_path_from_attr(outer_attrs, &self.directory.path) {
            return Ok(ModulePathSuccess {
                directory_ownership: match path.file_name().and_then(|s| s.to_str()) {
                    // All `#[path]` files are treated as though they are a `mod.rs` file.
                    // This means that `mod foo;` declarations inside `#[path]`-included
                    // files are siblings,
                    //
                    // Note that this will produce weirdness when a file named `foo.rs` is
                    // `#[path]` included and contains a `mod foo;` declaration.
                    // If you encounter this, it's your own darn fault :P
                    Some(_) => DirectoryOwnership::Owned { relative: None },
                    _ => DirectoryOwnership::UnownedViaMod,
                },
                path,
            });
        }

        let relative = match self.directory.ownership {
            DirectoryOwnership::Owned { relative } => relative,
            DirectoryOwnership::UnownedViaBlock |
            DirectoryOwnership::UnownedViaMod => None,
        };
        let paths = Parser::default_submod_path(
                        id, relative, &self.directory.path, self.sess.source_map());

        match self.directory.ownership {
            DirectoryOwnership::Owned { .. } => {
                paths.result.map_err(|err| self.span_fatal_err(id_sp, err))
            },
            DirectoryOwnership::UnownedViaBlock => {
                let msg =
                    "Cannot declare a non-inline module inside a block \
                    unless it has a path attribute";
                let mut err = self.diagnostic().struct_span_err(id_sp, msg);
                if paths.path_exists {
                    let msg = format!("Maybe `use` the module `{}` instead of redeclaring it",
                                      paths.name);
                    err.span_note(id_sp, &msg);
                }
                Err(err)
            }
            DirectoryOwnership::UnownedViaMod => {
                let mut err = self.diagnostic().struct_span_err(id_sp,
                    "cannot declare a new module at this location");
                if !id_sp.is_dummy() {
                    let src_path = self.sess.source_map().span_to_filename(id_sp);
                    if let FileName::Real(src_path) = src_path {
                        if let Some(stem) = src_path.file_stem() {
                            let mut dest_path = src_path.clone();
                            dest_path.set_file_name(stem);
                            dest_path.push("mod.rs");
                            err.span_note(id_sp,
                                    &format!("maybe move this module `{}` to its own \
                                                directory via `{}`", src_path.display(),
                                            dest_path.display()));
                        }
                    }
                }
                if paths.path_exists {
                    err.span_note(id_sp,
                                  &format!("... or maybe `use` the module `{}` instead \
                                            of possibly redeclaring it",
                                           paths.name));
                }
                Err(err)
            }
        }
    }

    pub(super) fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
        if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) {
            let s = s.as_str();

            // On windows, the base path might have the form
            // `\\?\foo\bar` in which case it does not tolerate
            // mixed `/` and `\` separators, so canonicalize
            // `/` to `\`.
            #[cfg(windows)]
            let s = s.replace("/", "\\");
            Some(dir_path.join(&*s))
        } else {
            None
        }
    }

    /// Returns a path to a module.
    pub(super) fn default_submod_path(
        id: ast::Ident,
        relative: Option<ast::Ident>,
        dir_path: &Path,
        source_map: &SourceMap) -> ModulePath
    {
        // If we're in a foo.rs file instead of a mod.rs file,
        // we need to look for submodules in
        // `./foo/<id>.rs` and `./foo/<id>/mod.rs` rather than
        // `./<id>.rs` and `./<id>/mod.rs`.
        let relative_prefix_string;
        let relative_prefix = if let Some(ident) = relative {
            relative_prefix_string = format!("{}{}", ident, path::MAIN_SEPARATOR);
            &relative_prefix_string
        } else {
            ""
        };

        let mod_name = id.to_string();
        let default_path_str = format!("{}{}.rs", relative_prefix, mod_name);
        let secondary_path_str = format!("{}{}{}mod.rs",
                                         relative_prefix, mod_name, path::MAIN_SEPARATOR);
        let default_path = dir_path.join(&default_path_str);
        let secondary_path = dir_path.join(&secondary_path_str);
        let default_exists = source_map.file_exists(&default_path);
        let secondary_exists = source_map.file_exists(&secondary_path);

        let result = match (default_exists, secondary_exists) {
            (true, false) => Ok(ModulePathSuccess {
                path: default_path,
                directory_ownership: DirectoryOwnership::Owned {
                    relative: Some(id),
                },
            }),
            (false, true) => Ok(ModulePathSuccess {
                path: secondary_path,
                directory_ownership: DirectoryOwnership::Owned {
                    relative: None,
                },
            }),
            (false, false) => Err(Error::FileNotFoundForModule {
                mod_name: mod_name.clone(),
                default_path: default_path_str,
                secondary_path: secondary_path_str,
                dir_path: dir_path.display().to_string(),
            }),
            (true, true) => Err(Error::DuplicatePaths {
                mod_name: mod_name.clone(),
                default_path: default_path_str,
                secondary_path: secondary_path_str,
            }),
        };

        ModulePath {
            name: mod_name,
            path_exists: default_exists || secondary_exists,
            result,
        }
    }

    /// Reads a module from a source file.
    fn eval_src_mod(
        &mut self,
        path: PathBuf,
        directory_ownership: DirectoryOwnership,
        name: String,
        id_sp: Span,
    ) -> PResult<'a, (Mod, Vec<Attribute>)> {
        let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
        if let Some(i) = included_mod_stack.iter().position(|p| *p == path) {
            let mut err = String::from("circular modules: ");
            let len = included_mod_stack.len();
            for p in &included_mod_stack[i.. len] {
                err.push_str(&p.to_string_lossy());
                err.push_str(" -> ");
            }
            err.push_str(&path.to_string_lossy());
            return Err(self.span_fatal(id_sp, &err[..]));
        }
        included_mod_stack.push(path.clone());
        drop(included_mod_stack);

        let mut p0 =
            new_sub_parser_from_file(self.sess, &path, directory_ownership, Some(name), id_sp);
        p0.cfg_mods = self.cfg_mods;
        let mod_inner_lo = p0.token.span;
        let mod_attrs = p0.parse_inner_attributes()?;
        let mut m0 = p0.parse_mod_items(&token::Eof, mod_inner_lo)?;
        m0.inline = false;
        self.sess.included_mod_stack.borrow_mut().pop();
        Ok((m0, mod_attrs))
    }

    fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
        if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) {
            self.directory.path.to_mut().push(&*path.as_str());
            self.directory.ownership = DirectoryOwnership::Owned { relative: None };
        } else {
            // We have to push on the current module name in the case of relative
            // paths in order to ensure that any additional module paths from inline
            // `mod x { ... }` come after the relative extension.
            //
            // For example, a `mod z { ... }` inside `x/y.rs` should set the current
            // directory path to `/x/y/z`, not `/x/z` with a relative offset of `y`.
            if let DirectoryOwnership::Owned { relative } = &mut self.directory.ownership {
                if let Some(ident) = relative.take() { // remove the relative offset
                    self.directory.path.to_mut().push(&*ident.as_str());
                }
            }
            self.directory.path.to_mut().push(&*id.as_str());
        }
    }
}