aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_hir_expand/src/builtin_macro.rs
blob: 631358f41a097b939a3f7254620149cc3ea64f33 (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
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
//! Builtin macro
use crate::{
    db::AstDatabase, name, quote, AstId, CrateId, EagerMacroId, LazyMacroId, MacroCallId,
    MacroDefId, MacroDefKind, TextSize,
};

use either::Either;
use mbe::parse_to_token_tree;
use ra_db::FileId;
use ra_parser::FragmentKind;
use ra_syntax::ast::{self, AstToken, HasStringValue};

macro_rules! register_builtin {
    ( LAZY: $(($name:ident, $kind: ident) => $expand:ident),* , EAGER: $(($e_name:ident, $e_kind: ident) => $e_expand:ident),*  ) => {
        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
        pub enum BuiltinFnLikeExpander {
            $($kind),*
        }

        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
        pub enum EagerExpander {
            $($e_kind),*
        }

        impl BuiltinFnLikeExpander {
            pub fn expand(
                &self,
                db: &dyn AstDatabase,
                id: LazyMacroId,
                tt: &tt::Subtree,
            ) -> Result<tt::Subtree, mbe::ExpandError> {
                let expander = match *self {
                    $( BuiltinFnLikeExpander::$kind => $expand, )*
                };
                expander(db, id, tt)
            }
        }

        impl EagerExpander {
            pub fn expand(
                &self,
                db: &dyn AstDatabase,
                arg_id: EagerMacroId,
                tt: &tt::Subtree,
            ) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
                let expander = match *self {
                    $( EagerExpander::$e_kind => $e_expand, )*
                };
                expander(db,arg_id,tt)
            }
        }

        fn find_by_name(ident: &name::Name) -> Option<Either<BuiltinFnLikeExpander, EagerExpander>> {
            match ident {
                $( id if id == &name::name![$name] => Some(Either::Left(BuiltinFnLikeExpander::$kind)), )*
                $( id if id == &name::name![$e_name] => Some(Either::Right(EagerExpander::$e_kind)), )*
                _ => return None,
            }
        }
    };
}

pub fn find_builtin_macro(
    ident: &name::Name,
    krate: CrateId,
    ast_id: AstId<ast::MacroCall>,
) -> Option<MacroDefId> {
    let kind = find_by_name(ident)?;

    match kind {
        Either::Left(kind) => Some(MacroDefId {
            krate: Some(krate),
            ast_id: Some(ast_id),
            kind: MacroDefKind::BuiltIn(kind),
            local_inner: false,
        }),
        Either::Right(kind) => Some(MacroDefId {
            krate: Some(krate),
            ast_id: Some(ast_id),
            kind: MacroDefKind::BuiltInEager(kind),
            local_inner: false,
        }),
    }
}

register_builtin! {
    LAZY:
    (column, Column) => column_expand,
    (compile_error, CompileError) => compile_error_expand,
    (file, File) => file_expand,
    (line, Line) => line_expand,
    (assert, Assert) => assert_expand,
    (stringify, Stringify) => stringify_expand,
    (format_args, FormatArgs) => format_args_expand,
    // format_args_nl only differs in that it adds a newline in the end,
    // so we use the same stub expansion for now
    (format_args_nl, FormatArgsNl) => format_args_expand,

    EAGER:
    (concat, Concat) => concat_expand,
    (include, Include) => include_expand,
    (include_str, IncludeStr) => include_str_expand,
    (env, Env) => env_expand,
    (option_env, OptionEnv) => option_env_expand
}

fn line_expand(
    _db: &dyn AstDatabase,
    _id: LazyMacroId,
    _tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    // dummy implementation for type-checking purposes
    let line_num = 0;
    let expanded = quote! {
        #line_num
    };

    Ok(expanded)
}

fn stringify_expand(
    db: &dyn AstDatabase,
    id: LazyMacroId,
    _tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    let loc = db.lookup_intern_macro(id);

    let macro_content = {
        let arg = loc.kind.arg(db).ok_or_else(|| mbe::ExpandError::UnexpectedToken)?;
        let macro_args = arg;
        let text = macro_args.text();
        let without_parens = TextSize::of('(')..text.len() - TextSize::of(')');
        text.slice(without_parens).to_string()
    };

    let expanded = quote! {
        #macro_content
    };

    Ok(expanded)
}

fn column_expand(
    _db: &dyn AstDatabase,
    _id: LazyMacroId,
    _tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    // dummy implementation for type-checking purposes
    let col_num = 0;
    let expanded = quote! {
        #col_num
    };

    Ok(expanded)
}

fn assert_expand(
    _db: &dyn AstDatabase,
    _id: LazyMacroId,
    tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    // A hacky implementation for goto def and hover
    // We expand `assert!(cond, arg1, arg2)` to
    // ```
    // {(cond, &(arg1), &(arg2));}
    // ```,
    // which is wrong but useful.

    let mut args = Vec::new();
    let mut current = Vec::new();
    for tt in tt.token_trees.iter().cloned() {
        match tt {
            tt::TokenTree::Leaf(tt::Leaf::Punct(p)) if p.char == ',' => {
                args.push(current);
                current = Vec::new();
            }
            _ => {
                current.push(tt);
            }
        }
    }
    if !current.is_empty() {
        args.push(current);
    }

    let arg_tts = args.into_iter().flat_map(|arg| {
        quote! { &(##arg), }
    }.token_trees).collect::<Vec<_>>();

    let expanded = quote! {
        { { (##arg_tts); } }
    };
    Ok(expanded)
}

fn file_expand(
    _db: &dyn AstDatabase,
    _id: LazyMacroId,
    _tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    // FIXME: RA purposefully lacks knowledge of absolute file names
    // so just return "".
    let file_name = "";

    let expanded = quote! {
        #file_name
    };

    Ok(expanded)
}

fn compile_error_expand(
    _db: &dyn AstDatabase,
    _id: LazyMacroId,
    tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    if tt.count() == 1 {
        if let tt::TokenTree::Leaf(tt::Leaf::Literal(it)) = &tt.token_trees[0] {
            let s = it.text.as_str();
            if s.contains('"') {
                return Ok(quote! { loop { #it }});
            }
        };
    }

    Err(mbe::ExpandError::BindingError("Must be a string".into()))
}

fn format_args_expand(
    _db: &dyn AstDatabase,
    _id: LazyMacroId,
    tt: &tt::Subtree,
) -> Result<tt::Subtree, mbe::ExpandError> {
    // We expand `format_args!("", a1, a2)` to
    // ```
    // std::fmt::Arguments::new_v1(&[], &[
    //   std::fmt::ArgumentV1::new(&arg1,std::fmt::Display::fmt),
    //   std::fmt::ArgumentV1::new(&arg2,std::fmt::Display::fmt),
    // ])
    // ```,
    // which is still not really correct, but close enough for now
    let mut args = Vec::new();
    let mut current = Vec::new();
    for tt in tt.token_trees.iter().cloned() {
        match tt {
            tt::TokenTree::Leaf(tt::Leaf::Punct(p)) if p.char == ',' => {
                args.push(current);
                current = Vec::new();
            }
            _ => {
                current.push(tt);
            }
        }
    }
    if !current.is_empty() {
        args.push(current);
    }
    if args.is_empty() {
        return Err(mbe::ExpandError::NoMatchingRule);
    }
    let _format_string = args.remove(0);
    let arg_tts = args.into_iter().flat_map(|arg| {
        quote! { std::fmt::ArgumentV1::new(&(##arg), std::fmt::Display::fmt), }
    }.token_trees).collect::<Vec<_>>();
    let expanded = quote! {
        std::fmt::Arguments::new_v1(&[], &[##arg_tts])
    };
    Ok(expanded)
}

fn unquote_str(lit: &tt::Literal) -> Option<String> {
    let lit = ast::make::tokens::literal(&lit.to_string());
    let token = ast::String::cast(lit)?;
    token.value()
}

fn concat_expand(
    _db: &dyn AstDatabase,
    _arg_id: EagerMacroId,
    tt: &tt::Subtree,
) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
    let mut text = String::new();
    for (i, t) in tt.token_trees.iter().enumerate() {
        match t {
            tt::TokenTree::Leaf(tt::Leaf::Literal(it)) if i % 2 == 0 => {
                text += &unquote_str(&it).ok_or_else(|| mbe::ExpandError::ConversionError)?;
            }
            tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) if i % 2 == 1 && punct.char == ',' => (),
            _ => return Err(mbe::ExpandError::UnexpectedToken),
        }
    }

    Ok((quote!(#text), FragmentKind::Expr))
}

fn relative_file(
    db: &dyn AstDatabase,
    call_id: MacroCallId,
    path: &str,
    allow_recursion: bool,
) -> Option<FileId> {
    let call_site = call_id.as_file().original_file(db);
    let res = db.resolve_path(call_site, path)?;
    // Prevent include itself
    if res == call_site && !allow_recursion {
        None
    } else {
        Some(res)
    }
}

fn parse_string(tt: &tt::Subtree) -> Result<String, mbe::ExpandError> {
    tt.token_trees
        .get(0)
        .and_then(|tt| match tt {
            tt::TokenTree::Leaf(tt::Leaf::Literal(it)) => unquote_str(&it),
            _ => None,
        })
        .ok_or_else(|| mbe::ExpandError::ConversionError)
}

fn include_expand(
    db: &dyn AstDatabase,
    arg_id: EagerMacroId,
    tt: &tt::Subtree,
) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
    let path = parse_string(tt)?;
    let file_id = relative_file(db, arg_id.into(), &path, false)
        .ok_or_else(|| mbe::ExpandError::ConversionError)?;

    // FIXME:
    // Handle include as expression
    let res = parse_to_token_tree(&db.file_text(file_id))
        .ok_or_else(|| mbe::ExpandError::ConversionError)?
        .0;

    Ok((res, FragmentKind::Items))
}

fn include_str_expand(
    db: &dyn AstDatabase,
    arg_id: EagerMacroId,
    tt: &tt::Subtree,
) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
    let path = parse_string(tt)?;

    // FIXME: we're not able to read excluded files (which is most of them because
    // it's unusual to `include_str!` a Rust file), but we can return an empty string.
    // Ideally, we'd be able to offer a precise expansion if the user asks for macro
    // expansion.
    let file_id = match relative_file(db, arg_id.into(), &path, true) {
        Some(file_id) => file_id,
        None => {
            return Ok((quote!(""), FragmentKind::Expr));
        }
    };

    let text = db.file_text(file_id);
    let text = &*text;

    Ok((quote!(#text), FragmentKind::Expr))
}

fn get_env_inner(db: &dyn AstDatabase, arg_id: EagerMacroId, key: &str) -> Option<String> {
    let krate = db.lookup_intern_eager_expansion(arg_id).krate;
    db.crate_graph()[krate].env.get(key)
}

fn env_expand(
    db: &dyn AstDatabase,
    arg_id: EagerMacroId,
    tt: &tt::Subtree,
) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
    let key = parse_string(tt)?;

    // FIXME:
    // If the environment variable is not defined int rustc, then a compilation error will be emitted.
    // We might do the same if we fully support all other stuffs.
    // But for now on, we should return some dummy string for better type infer purpose.
    // However, we cannot use an empty string here, because for
    // `include!(concat!(env!("OUT_DIR"), "/foo.rs"))` will become
    // `include!("foo.rs"), which might go to infinite loop
    let s = get_env_inner(db, arg_id, &key).unwrap_or_else(|| "__RA_UNIMPLEMENTED__".to_string());
    let expanded = quote! { #s };

    Ok((expanded, FragmentKind::Expr))
}

fn option_env_expand(
    db: &dyn AstDatabase,
    arg_id: EagerMacroId,
    tt: &tt::Subtree,
) -> Result<(tt::Subtree, FragmentKind), mbe::ExpandError> {
    let key = parse_string(tt)?;
    let expanded = match get_env_inner(db, arg_id, &key) {
        None => quote! { std::option::Option::None::<&str> },
        Some(s) => quote! { std::option::Some(#s) },
    };

    Ok((expanded, FragmentKind::Expr))
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{
        name::AsName, test_db::TestDB, AstNode, EagerCallLoc, MacroCallId, MacroCallKind,
        MacroCallLoc,
    };
    use ra_db::{fixture::WithFixture, SourceDatabase};
    use ra_syntax::ast::NameOwner;
    use std::sync::Arc;

    fn expand_builtin_macro(ra_fixture: &str) -> String {
        let (db, file_id) = TestDB::with_single_file(&ra_fixture);
        let parsed = db.parse(file_id);
        let macro_calls: Vec<_> =
            parsed.syntax_node().descendants().filter_map(ast::MacroCall::cast).collect();

        let ast_id_map = db.ast_id_map(file_id.into());

        let expander = find_by_name(&macro_calls[0].name().unwrap().as_name()).unwrap();

        let krate = CrateId(0);
        let file_id = match expander {
            Either::Left(expander) => {
                // the first one should be a macro_rules
                let def = MacroDefId {
                    krate: Some(CrateId(0)),
                    ast_id: Some(AstId::new(file_id.into(), ast_id_map.ast_id(&macro_calls[0]))),
                    kind: MacroDefKind::BuiltIn(expander),
                    local_inner: false,
                };

                let loc = MacroCallLoc {
                    def,
                    krate,
                    kind: MacroCallKind::FnLike(AstId::new(
                        file_id.into(),
                        ast_id_map.ast_id(&macro_calls[1]),
                    )),
                };

                let id: MacroCallId = db.intern_macro(loc).into();
                id.as_file()
            }
            Either::Right(expander) => {
                // the first one should be a macro_rules
                let def = MacroDefId {
                    krate: Some(krate),
                    ast_id: Some(AstId::new(file_id.into(), ast_id_map.ast_id(&macro_calls[0]))),
                    kind: MacroDefKind::BuiltInEager(expander),
                    local_inner: false,
                };

                let args = macro_calls[1].token_tree().unwrap();
                let parsed_args = mbe::ast_to_token_tree(&args).unwrap().0;

                let arg_id = db.intern_eager_expansion({
                    EagerCallLoc {
                        def,
                        fragment: FragmentKind::Expr,
                        subtree: Arc::new(parsed_args.clone()),
                        krate,
                        file_id: file_id.into(),
                    }
                });

                let (subtree, fragment) = expander.expand(&db, arg_id, &parsed_args).unwrap();
                let eager = EagerCallLoc {
                    def,
                    fragment,
                    subtree: Arc::new(subtree),
                    krate,
                    file_id: file_id.into(),
                };

                let id: MacroCallId = db.intern_eager_expansion(eager).into();
                id.as_file()
            }
        };

        db.parse_or_expand(file_id).unwrap().to_string()
    }

    #[test]
    fn test_column_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! column {() => {}}
            column!()
            "#,
        );

        assert_eq!(expanded, "0");
    }

    #[test]
    fn test_line_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! line {() => {}}
            line!()
            "#,
        );

        assert_eq!(expanded, "0");
    }

    #[test]
    fn test_stringify_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! stringify {() => {}}
            stringify!(a b c)
            "#,
        );

        assert_eq!(expanded, "\"a b c\"");
    }

    #[test]
    fn test_env_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! env {() => {}}
            env!("TEST_ENV_VAR")
            "#,
        );

        assert_eq!(expanded, "\"__RA_UNIMPLEMENTED__\"");
    }

    #[test]
    fn test_option_env_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! option_env {() => {}}
            option_env!("TEST_ENV_VAR")
            "#,
        );

        assert_eq!(expanded, "std::option::Option::None:: < &str>");
    }

    #[test]
    fn test_file_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! file {() => {}}
            file!()
            "#,
        );

        assert_eq!(expanded, "\"\"");
    }

    #[test]
    fn test_assert_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! assert {
                ($cond:expr) => ({ /* compiler built-in */ });
                ($cond:expr, $($args:tt)*) => ({ /* compiler built-in */ })
            }
            assert!(true, "{} {:?}", arg1(a, b, c), arg2);
            "#,
        );

        assert_eq!(expanded, "{{(&(true), &(\"{} {:?}\"), &(arg1(a,b,c)), &(arg2),);}}");
    }

    #[test]
    fn test_compile_error_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! compile_error {
                ($msg:expr) => ({ /* compiler built-in */ });
                ($msg:expr,) => ({ /* compiler built-in */ })
            }
            compile_error!("error!");
            "#,
        );

        assert_eq!(expanded, r#"loop{"error!"}"#);
    }

    #[test]
    fn test_format_args_expand() {
        let expanded = expand_builtin_macro(
            r#"
            #[rustc_builtin_macro]
            macro_rules! format_args {
                ($fmt:expr) => ({ /* compiler built-in */ });
                ($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
            }
            format_args!("{} {:?}", arg1(a, b, c), arg2);
            "#,
        );

        assert_eq!(
            expanded,
            r#"std::fmt::Arguments::new_v1(&[], &[std::fmt::ArgumentV1::new(&(arg1(a,b,c)),std::fmt::Display::fmt),std::fmt::ArgumentV1::new(&(arg2),std::fmt::Display::fmt),])"#
        );
    }
}