aboutsummaryrefslogtreecommitdiff
path: root/crates/hir_def/src/attr.rs
blob: 0360fb6270558d906445fba46db41eb6aa703d9f (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
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
//! A higher level attributes based on TokenTree, with also some shortcuts.

use std::{ops, sync::Arc};

use base_db::CrateId;
use cfg::{CfgExpr, CfgOptions};
use either::Either;
use hir_expand::{hygiene::Hygiene, name::AsName, AstId, InFile};
use itertools::Itertools;
use la_arena::ArenaMap;
use mbe::ast_to_token_tree;
use smallvec::{smallvec, SmallVec};
use syntax::{
    ast::{self, AstNode, AttrsOwner},
    match_ast, AstToken, SmolStr, SyntaxNode,
};
use tt::Subtree;

use crate::{
    db::DefDatabase,
    item_tree::{ItemTreeId, ItemTreeNode},
    nameres::ModuleSource,
    path::{ModPath, PathKind},
    src::HasChildSource,
    AdtId, AttrDefId, EnumId, GenericParamId, HasModule, LocalEnumVariantId, LocalFieldId, Lookup,
    VariantId,
};

/// Holds documentation
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Documentation(String);

impl Documentation {
    pub fn as_str(&self) -> &str {
        &self.0
    }
}

impl From<Documentation> for String {
    fn from(Documentation(string): Documentation) -> Self {
        string
    }
}

/// Syntactical attributes, without filtering of `cfg_attr`s.
#[derive(Default, Debug, Clone, PartialEq, Eq)]
pub(crate) struct RawAttrs {
    entries: Option<Arc<[Attr]>>,
}

#[derive(Default, Debug, Clone, PartialEq, Eq)]
pub struct Attrs(RawAttrs);

impl ops::Deref for RawAttrs {
    type Target = [Attr];

    fn deref(&self) -> &[Attr] {
        match &self.entries {
            Some(it) => &*it,
            None => &[],
        }
    }
}

impl ops::Deref for Attrs {
    type Target = [Attr];

    fn deref(&self) -> &[Attr] {
        match &self.0.entries {
            Some(it) => &*it,
            None => &[],
        }
    }
}

impl RawAttrs {
    pub(crate) const EMPTY: Self = Self { entries: None };

    pub(crate) fn new(owner: &dyn ast::AttrsOwner, hygiene: &Hygiene) -> Self {
        let entries = collect_attrs(owner)
            .enumerate()
            .flat_map(|(i, attr)| match attr {
                Either::Left(attr) => Attr::from_src(attr, hygiene, i as u32),
                Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
                    index: i as u32,
                    input: Some(AttrInput::Literal(SmolStr::new(doc))),
                    path: ModPath::from(hir_expand::name!(doc)),
                }),
            })
            .collect::<Arc<_>>();

        Self { entries: if entries.is_empty() { None } else { Some(entries) } }
    }

    fn from_attrs_owner(db: &dyn DefDatabase, owner: InFile<&dyn ast::AttrsOwner>) -> Self {
        let hygiene = Hygiene::new(db.upcast(), owner.file_id);
        Self::new(owner.value, &hygiene)
    }

    pub(crate) fn merge(&self, other: Self) -> Self {
        match (&self.entries, &other.entries) {
            (None, None) => Self::EMPTY,
            (Some(entries), None) | (None, Some(entries)) => {
                Self { entries: Some(entries.clone()) }
            }
            (Some(a), Some(b)) => {
                Self { entries: Some(a.iter().chain(b.iter()).cloned().collect()) }
            }
        }
    }

    /// Processes `cfg_attr`s, returning the resulting semantic `Attrs`.
    pub(crate) fn filter(self, db: &dyn DefDatabase, krate: CrateId) -> Attrs {
        let has_cfg_attrs = self.iter().any(|attr| {
            attr.path.as_ident().map_or(false, |name| *name == hir_expand::name![cfg_attr])
        });
        if !has_cfg_attrs {
            return Attrs(self);
        }

        let crate_graph = db.crate_graph();
        let new_attrs = self
            .iter()
            .flat_map(|attr| -> SmallVec<[_; 1]> {
                let is_cfg_attr =
                    attr.path.as_ident().map_or(false, |name| *name == hir_expand::name![cfg_attr]);
                if !is_cfg_attr {
                    return smallvec![attr.clone()];
                }

                let subtree = match &attr.input {
                    Some(AttrInput::TokenTree(it)) => it,
                    _ => return smallvec![attr.clone()],
                };

                // Input subtree is: `(cfg, $(attr),+)`
                // Split it up into a `cfg` subtree and the `attr` subtrees.
                // FIXME: There should be a common API for this.
                let mut parts = subtree.token_trees.split(
                    |tt| matches!(tt, tt::TokenTree::Leaf(tt::Leaf::Punct(p)) if p.char == ','),
                );
                let cfg = parts.next().unwrap();
                let cfg = Subtree { delimiter: subtree.delimiter, token_trees: cfg.to_vec() };
                let cfg = CfgExpr::parse(&cfg);
                let index = attr.index;
                let attrs = parts.filter(|a| !a.is_empty()).filter_map(|attr| {
                    let tree = Subtree { delimiter: None, token_trees: attr.to_vec() };
                    let attr = ast::Attr::parse(&format!("#[{}]", tree)).ok()?;
                    // FIXME hygiene
                    let hygiene = Hygiene::new_unhygienic();
                    Attr::from_src(attr, &hygiene, index)
                });

                let cfg_options = &crate_graph[krate].cfg_options;
                if cfg_options.check(&cfg) == Some(false) {
                    smallvec![]
                } else {
                    cov_mark::hit!(cfg_attr_active);

                    attrs.collect()
                }
            })
            .collect();

        Attrs(RawAttrs { entries: Some(new_attrs) })
    }
}

impl Attrs {
    pub const EMPTY: Self = Self(RawAttrs::EMPTY);

    pub(crate) fn attrs_query(db: &dyn DefDatabase, def: AttrDefId) -> Attrs {
        let raw_attrs = match def {
            AttrDefId::ModuleId(module) => {
                let def_map = module.def_map(db);
                let mod_data = &def_map[module.local_id];
                match mod_data.declaration_source(db) {
                    Some(it) => {
                        let raw_attrs = RawAttrs::from_attrs_owner(
                            db,
                            it.as_ref().map(|it| it as &dyn ast::AttrsOwner),
                        );
                        match mod_data.definition_source(db) {
                            InFile { file_id, value: ModuleSource::SourceFile(file) } => raw_attrs
                                .merge(RawAttrs::from_attrs_owner(db, InFile::new(file_id, &file))),
                            _ => raw_attrs,
                        }
                    }
                    None => RawAttrs::from_attrs_owner(
                        db,
                        mod_data.definition_source(db).as_ref().map(|src| match src {
                            ModuleSource::SourceFile(file) => file as &dyn ast::AttrsOwner,
                            ModuleSource::Module(module) => module as &dyn ast::AttrsOwner,
                            ModuleSource::BlockExpr(block) => block as &dyn ast::AttrsOwner,
                        }),
                    ),
                }
            }
            AttrDefId::FieldId(it) => {
                return db.fields_attrs(it.parent)[it.local_id].clone();
            }
            AttrDefId::EnumVariantId(it) => {
                return db.variants_attrs(it.parent)[it.local_id].clone();
            }
            AttrDefId::AdtId(it) => match it {
                AdtId::StructId(it) => attrs_from_item_tree(it.lookup(db).id, db),
                AdtId::EnumId(it) => attrs_from_item_tree(it.lookup(db).id, db),
                AdtId::UnionId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            },
            AttrDefId::TraitId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            AttrDefId::MacroDefId(it) => {
                it.ast_id().map_or_else(Default::default, |ast_id| attrs_from_ast(ast_id, db))
            }
            AttrDefId::ImplId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            AttrDefId::ConstId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            AttrDefId::StaticId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            AttrDefId::FunctionId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            AttrDefId::TypeAliasId(it) => attrs_from_item_tree(it.lookup(db).id, db),
            AttrDefId::GenericParamId(it) => match it {
                GenericParamId::TypeParamId(it) => {
                    let src = it.parent.child_source(db);
                    RawAttrs::from_attrs_owner(
                        db,
                        src.with_value(
                            src.value[it.local_id].as_ref().either(|it| it as _, |it| it as _),
                        ),
                    )
                }
                GenericParamId::LifetimeParamId(it) => {
                    let src = it.parent.child_source(db);
                    RawAttrs::from_attrs_owner(db, src.with_value(&src.value[it.local_id]))
                }
                GenericParamId::ConstParamId(it) => {
                    let src = it.parent.child_source(db);
                    RawAttrs::from_attrs_owner(db, src.with_value(&src.value[it.local_id]))
                }
            },
        };

        raw_attrs.filter(db, def.krate(db))
    }

    pub(crate) fn variants_attrs_query(
        db: &dyn DefDatabase,
        e: EnumId,
    ) -> Arc<ArenaMap<LocalEnumVariantId, Attrs>> {
        let krate = e.lookup(db).container.krate;
        let src = e.child_source(db);
        let mut res = ArenaMap::default();

        for (id, var) in src.value.iter() {
            let attrs = RawAttrs::from_attrs_owner(db, src.with_value(var as &dyn ast::AttrsOwner))
                .filter(db, krate);

            res.insert(id, attrs)
        }

        Arc::new(res)
    }

    pub(crate) fn fields_attrs_query(
        db: &dyn DefDatabase,
        v: VariantId,
    ) -> Arc<ArenaMap<LocalFieldId, Attrs>> {
        let krate = v.module(db).krate;
        let src = v.child_source(db);
        let mut res = ArenaMap::default();

        for (id, fld) in src.value.iter() {
            let attrs = match fld {
                Either::Left(_tuple) => Attrs::default(),
                Either::Right(record) => {
                    RawAttrs::from_attrs_owner(db, src.with_value(record)).filter(db, krate)
                }
            };

            res.insert(id, attrs);
        }

        Arc::new(res)
    }

    /// Constructs a map that maps the lowered `Attr`s in this `Attrs` back to its original syntax nodes.
    ///
    /// `owner` must be the original owner of the attributes.
    // FIXME: figure out a better api that doesnt require the for_module hack
    pub fn source_map(&self, owner: InFile<&dyn ast::AttrsOwner>) -> AttrSourceMap {
        // FIXME: This doesn't work correctly for modules, as the attributes there can have up to
        // two different owners
        AttrSourceMap {
            attrs: collect_attrs(owner.value)
                .map(|attr| InFile::new(owner.file_id, attr))
                .collect(),
        }
    }

    pub fn source_map_for_module(
        &self,
        db: &dyn DefDatabase,
        module: crate::ModuleId,
    ) -> AttrSourceMap {
        let def_map = module.def_map(db);
        let mod_data = &def_map[module.local_id];
        let attrs = match mod_data.declaration_source(db) {
            Some(it) => {
                let mut attrs: Vec<_> = collect_attrs(&it.value as &dyn ast::AttrsOwner)
                    .map(|attr| InFile::new(it.file_id, attr))
                    .collect();
                if let InFile { file_id, value: ModuleSource::SourceFile(file) } =
                    mod_data.definition_source(db)
                {
                    attrs.extend(
                        collect_attrs(&file as &dyn ast::AttrsOwner)
                            .map(|attr| InFile::new(file_id, attr)),
                    )
                }
                attrs
            }
            None => {
                let InFile { file_id, value } = mod_data.definition_source(db);
                match &value {
                    ModuleSource::SourceFile(file) => collect_attrs(file as &dyn ast::AttrsOwner),
                    ModuleSource::Module(module) => collect_attrs(module as &dyn ast::AttrsOwner),
                    ModuleSource::BlockExpr(block) => collect_attrs(block as &dyn ast::AttrsOwner),
                }
                .map(|attr| InFile::new(file_id, attr))
                .collect()
            }
        };
        AttrSourceMap { attrs }
    }

    pub fn by_key(&self, key: &'static str) -> AttrQuery<'_> {
        AttrQuery { attrs: self, key }
    }

    pub fn cfg(&self) -> Option<CfgExpr> {
        let mut cfgs = self.by_key("cfg").tt_values().map(CfgExpr::parse).collect::<Vec<_>>();
        match cfgs.len() {
            0 => None,
            1 => Some(cfgs.pop().unwrap()),
            _ => Some(CfgExpr::All(cfgs)),
        }
    }
    pub(crate) fn is_cfg_enabled(&self, cfg_options: &CfgOptions) -> bool {
        match self.cfg() {
            None => true,
            Some(cfg) => cfg_options.check(&cfg) != Some(false),
        }
    }

    pub fn docs(&self) -> Option<Documentation> {
        let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_ref()? {
            AttrInput::Literal(s) => Some(s),
            AttrInput::TokenTree(_) => None,
        });
        let indent = docs
            .clone()
            .flat_map(|s| s.lines())
            .filter(|line| !line.chars().all(|c| c.is_whitespace()))
            .map(|line| line.chars().take_while(|c| c.is_whitespace()).count())
            .min()
            .unwrap_or(0);
        let mut buf = String::new();
        for doc in docs {
            // str::lines doesn't yield anything for the empty string
            if !doc.is_empty() {
                buf.extend(Itertools::intersperse(
                    doc.lines().map(|line| {
                        line.char_indices()
                            .nth(indent)
                            .map_or(line, |(offset, _)| &line[offset..])
                            .trim_end()
                    }),
                    "\n",
                ));
            }
            buf.push('\n');
        }
        buf.pop();
        if buf.is_empty() {
            None
        } else {
            Some(Documentation(buf))
        }
    }
}

fn inner_attributes(
    syntax: &SyntaxNode,
) -> Option<(impl Iterator<Item = ast::Attr>, impl Iterator<Item = ast::Comment>)> {
    let (attrs, docs) = match_ast! {
        match syntax {
            ast::SourceFile(it) => (it.attrs(), ast::CommentIter::from_syntax_node(it.syntax())),
            ast::ExternBlock(it) => {
                let extern_item_list = it.extern_item_list()?;
                (extern_item_list.attrs(), ast::CommentIter::from_syntax_node(extern_item_list.syntax()))
            },
            ast::Fn(it) => {
                let body = it.body()?;
                (body.attrs(), ast::CommentIter::from_syntax_node(body.syntax()))
            },
            ast::Impl(it) => {
                let assoc_item_list = it.assoc_item_list()?;
                (assoc_item_list.attrs(), ast::CommentIter::from_syntax_node(assoc_item_list.syntax()))
            },
            ast::Module(it) => {
                let item_list = it.item_list()?;
                (item_list.attrs(), ast::CommentIter::from_syntax_node(item_list.syntax()))
            },
            // FIXME: BlockExpr's only accept inner attributes in specific cases
            // Excerpt from the reference:
            // Block expressions accept outer and inner attributes, but only when they are the outer
            // expression of an expression statement or the final expression of another block expression.
            ast::BlockExpr(_it) => return None,
            _ => return None,
        }
    };
    let attrs = attrs.filter(|attr| attr.excl_token().is_some());
    let docs = docs.filter(|doc| doc.is_inner());
    Some((attrs, docs))
}

pub struct AttrSourceMap {
    attrs: Vec<InFile<Either<ast::Attr, ast::Comment>>>,
}

impl AttrSourceMap {
    /// Maps the lowered `Attr` back to its original syntax node.
    ///
    /// `attr` must come from the `owner` used for AttrSourceMap
    ///
    /// Note that the returned syntax node might be a `#[cfg_attr]`, or a doc comment, instead of
    /// the attribute represented by `Attr`.
    pub fn source_of(&self, attr: &Attr) -> InFile<&Either<ast::Attr, ast::Comment>> {
        self.attrs
            .get(attr.index as usize)
            .unwrap_or_else(|| panic!("cannot find `Attr` at index {}", attr.index))
            .as_ref()
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Attr {
    index: u32,
    pub(crate) path: ModPath,
    pub(crate) input: Option<AttrInput>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum AttrInput {
    /// `#[attr = "string"]`
    Literal(SmolStr),
    /// `#[attr(subtree)]`
    TokenTree(Subtree),
}

impl Attr {
    fn from_src(ast: ast::Attr, hygiene: &Hygiene, index: u32) -> Option<Attr> {
        let path = ModPath::from_src(ast.path()?, hygiene)?;
        let input = if let Some(ast::Expr::Literal(lit)) = ast.expr() {
            let value = match lit.kind() {
                ast::LiteralKind::String(string) => string.value()?.into(),
                _ => lit.syntax().first_token()?.text().trim_matches('"').into(),
            };
            Some(AttrInput::Literal(value))
        } else if let Some(tt) = ast.token_tree() {
            Some(AttrInput::TokenTree(ast_to_token_tree(&tt)?.0))
        } else {
            None
        };
        Some(Attr { index, path, input })
    }

    /// Parses this attribute as a `#[derive]`, returns an iterator that yields all contained paths
    /// to derive macros.
    ///
    /// Returns `None` when the attribute is not a well-formed `#[derive]` attribute.
    pub(crate) fn parse_derive(&self) -> Option<impl Iterator<Item = ModPath>> {
        if self.path.as_ident() != Some(&hir_expand::name![derive]) {
            return None;
        }

        match &self.input {
            Some(AttrInput::TokenTree(args)) => {
                let mut counter = 0;
                let paths = args
                    .token_trees
                    .iter()
                    .group_by(move |tt| {
                        match tt {
                            tt::TokenTree::Leaf(tt::Leaf::Punct(p)) if p.char == ',' => {
                                counter += 1;
                            }
                            _ => {}
                        }
                        counter
                    })
                    .into_iter()
                    .map(|(_, tts)| {
                        let segments = tts.filter_map(|tt| match tt {
                            tt::TokenTree::Leaf(tt::Leaf::Ident(id)) => Some(id.as_name()),
                            _ => None,
                        });
                        ModPath::from_segments(PathKind::Plain, segments)
                    })
                    .collect::<Vec<_>>();

                Some(paths.into_iter())
            }
            _ => None,
        }
    }

    pub fn string_value(&self) -> Option<&SmolStr> {
        match self.input.as_ref()? {
            AttrInput::Literal(it) => Some(it),
            _ => None,
        }
    }
}

#[derive(Debug, Clone, Copy)]
pub struct AttrQuery<'a> {
    attrs: &'a Attrs,
    key: &'static str,
}

impl<'a> AttrQuery<'a> {
    pub fn tt_values(self) -> impl Iterator<Item = &'a Subtree> {
        self.attrs().filter_map(|attr| match attr.input.as_ref()? {
            AttrInput::TokenTree(it) => Some(it),
            _ => None,
        })
    }

    pub fn string_value(self) -> Option<&'a SmolStr> {
        self.attrs().find_map(|attr| match attr.input.as_ref()? {
            AttrInput::Literal(it) => Some(it),
            _ => None,
        })
    }

    pub fn exists(self) -> bool {
        self.attrs().next().is_some()
    }

    pub fn attrs(self) -> impl Iterator<Item = &'a Attr> + Clone {
        let key = self.key;
        self.attrs
            .iter()
            .filter(move |attr| attr.path.as_ident().map_or(false, |s| s.to_string() == key))
    }
}

fn attrs_from_ast<N>(src: AstId<N>, db: &dyn DefDatabase) -> RawAttrs
where
    N: ast::AttrsOwner,
{
    let src = InFile::new(src.file_id, src.to_node(db.upcast()));
    RawAttrs::from_attrs_owner(db, src.as_ref().map(|it| it as &dyn ast::AttrsOwner))
}

fn attrs_from_item_tree<N: ItemTreeNode>(id: ItemTreeId<N>, db: &dyn DefDatabase) -> RawAttrs {
    let tree = id.item_tree(db);
    let mod_item = N::id_to_mod_item(id.value);
    tree.raw_attrs(mod_item.into()).clone()
}

fn collect_attrs(
    owner: &dyn ast::AttrsOwner,
) -> impl Iterator<Item = Either<ast::Attr, ast::Comment>> {
    let (inner_attrs, inner_docs) = inner_attributes(owner.syntax())
        .map_or((None, None), |(attrs, docs)| ((Some(attrs), Some(docs))));

    let outer_attrs = owner.attrs().filter(|attr| attr.excl_token().is_none());
    let attrs = outer_attrs
        .chain(inner_attrs.into_iter().flatten())
        .map(|attr| (attr.syntax().text_range().start(), Either::Left(attr)));

    let outer_docs =
        ast::CommentIter::from_syntax_node(owner.syntax()).filter(ast::Comment::is_outer);
    let docs = outer_docs
        .chain(inner_docs.into_iter().flatten())
        .map(|docs_text| (docs_text.syntax().text_range().start(), Either::Right(docs_text)));
    // sort here by syntax node offset because the source can have doc attributes and doc strings be interleaved
    let attrs: Vec<_> = docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).collect();

    attrs.into_iter().map(|(_, attr)| attr)
}