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
use crate::clean::auto_trait::AutoTraitFinder;
use crate::clean::blanket_impl::BlanketImplFinder;
use crate::clean::{
    inline, Clean, Crate, Generic, GenericArg, GenericArgs, ImportSource, Item, ItemKind, Lifetime,
    MacroKind, Path, PathSegment, Primitive, PrimitiveType, ResolvedPath, Type, TypeBinding,
};
use crate::core::DocContext;
use crate::formats::item_type::ItemType;

use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
use rustc_middle::mir::interpret::ConstValue;
use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
use rustc_middle::ty::{self, DefIdTree, TyCtxt};
use rustc_span::symbol::{kw, sym, Symbol};
use std::mem;

#[cfg(test)]
mod tests;

crate fn krate(cx: &mut DocContext<'_>) -> Crate {
    use crate::visit_lib::LibEmbargoVisitor;

    let krate = cx.tcx.hir().krate();
    let module = crate::visit_ast::RustdocVisitor::new(cx).visit(krate);

    cx.cache.deref_trait_did = cx.tcx.lang_items().deref_trait();
    cx.cache.deref_mut_trait_did = cx.tcx.lang_items().deref_mut_trait();
    cx.cache.owned_box_did = cx.tcx.lang_items().owned_box();

    let mut externs = Vec::new();
    for &cnum in cx.tcx.crates().iter() {
        externs.push((cnum, cnum.clean(cx)));
        // Analyze doc-reachability for extern items
        LibEmbargoVisitor::new(cx).visit_lib(cnum);
    }
    externs.sort_by(|&(a, _), &(b, _)| a.cmp(&b));

    // Clean the crate, translating the entire librustc_ast AST to one that is
    // understood by rustdoc.
    let mut module = module.clean(cx);

    match *module.kind {
        ItemKind::ModuleItem(ref module) => {
            for it in &module.items {
                // `compiler_builtins` should be masked too, but we can't apply
                // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
                if it.is_extern_crate()
                    && (it.attrs.has_doc_flag(sym::masked)
                        || cx.tcx.is_compiler_builtins(it.def_id.krate()))
                {
                    cx.cache.masked_crates.insert(it.def_id.krate());
                }
            }
        }
        _ => unreachable!(),
    }

    let local_crate = LOCAL_CRATE.clean(cx);
    let src = local_crate.src(cx.tcx);
    let name = local_crate.name(cx.tcx);
    let primitives = local_crate.primitives(cx.tcx);
    let keywords = local_crate.keywords(cx.tcx);
    {
        let m = match *module.kind {
            ItemKind::ModuleItem(ref mut m) => m,
            _ => unreachable!(),
        };
        m.items.extend(primitives.iter().map(|&(def_id, prim)| {
            Item::from_def_id_and_parts(
                def_id,
                Some(prim.as_sym()),
                ItemKind::PrimitiveItem(prim),
                cx,
            )
        }));
        m.items.extend(keywords.into_iter().map(|(def_id, kw)| {
            Item::from_def_id_and_parts(def_id, Some(kw), ItemKind::KeywordItem(kw), cx)
        }));
    }

    Crate {
        name,
        src,
        module,
        externs,
        primitives,
        external_traits: cx.external_traits.clone(),
        collapsed: false,
    }
}

fn external_generic_args(
    cx: &mut DocContext<'_>,
    trait_did: Option<DefId>,
    has_self: bool,
    bindings: Vec<TypeBinding>,
    substs: SubstsRef<'_>,
) -> GenericArgs {
    let mut skip_self = has_self;
    let mut ty_kind = None;
    let args: Vec<_> = substs
        .iter()
        .filter_map(|kind| match kind.unpack() {
            GenericArgKind::Lifetime(lt) => match lt {
                ty::ReLateBound(_, ty::BoundRegion { kind: ty::BrAnon(_), .. }) => {
                    Some(GenericArg::Lifetime(Lifetime::elided()))
                }
                _ => lt.clean(cx).map(GenericArg::Lifetime),
            },
            GenericArgKind::Type(_) if skip_self => {
                skip_self = false;
                None
            }
            GenericArgKind::Type(ty) => {
                ty_kind = Some(ty.kind());
                Some(GenericArg::Type(ty.clean(cx)))
            }
            GenericArgKind::Const(ct) => Some(GenericArg::Const(ct.clean(cx))),
        })
        .collect();

    match trait_did {
        // Attempt to sugar an external path like Fn<(A, B,), C> to Fn(A, B) -> C
        Some(did) if cx.tcx.fn_trait_kind_from_lang_item(did).is_some() => {
            assert!(ty_kind.is_some());
            let inputs = match ty_kind {
                Some(ty::Tuple(ref tys)) => tys.iter().map(|t| t.expect_ty().clean(cx)).collect(),
                _ => return GenericArgs::AngleBracketed { args, bindings },
            };
            let output = None;
            // FIXME(#20299) return type comes from a projection now
            // match types[1].kind {
            //     ty::Tuple(ref v) if v.is_empty() => None, // -> ()
            //     _ => Some(types[1].clean(cx))
            // };
            GenericArgs::Parenthesized { inputs, output }
        }
        _ => GenericArgs::AngleBracketed { args, bindings },
    }
}

// trait_did should be set to a trait's DefId if called on a TraitRef, in order to sugar
// from Fn<(A, B,), C> to Fn(A, B) -> C
pub(super) fn external_path(
    cx: &mut DocContext<'_>,
    name: Symbol,
    trait_did: Option<DefId>,
    has_self: bool,
    bindings: Vec<TypeBinding>,
    substs: SubstsRef<'_>,
) -> Path {
    Path {
        global: false,
        res: Res::Err,
        segments: vec![PathSegment {
            name,
            args: external_generic_args(cx, trait_did, has_self, bindings, substs),
        }],
    }
}

crate fn strip_type(ty: Type) -> Type {
    match ty {
        Type::ResolvedPath { path, param_names, did, is_generic } => {
            Type::ResolvedPath { path: strip_path(&path), param_names, did, is_generic }
        }
        Type::Tuple(inner_tys) => {
            Type::Tuple(inner_tys.iter().map(|t| strip_type(t.clone())).collect())
        }
        Type::Slice(inner_ty) => Type::Slice(Box::new(strip_type(*inner_ty))),
        Type::Array(inner_ty, s) => Type::Array(Box::new(strip_type(*inner_ty)), s),
        Type::RawPointer(m, inner_ty) => Type::RawPointer(m, Box::new(strip_type(*inner_ty))),
        Type::BorrowedRef { lifetime, mutability, type_ } => {
            Type::BorrowedRef { lifetime, mutability, type_: Box::new(strip_type(*type_)) }
        }
        Type::QPath { name, self_type, trait_ } => Type::QPath {
            name,
            self_type: Box::new(strip_type(*self_type)),
            trait_: Box::new(strip_type(*trait_)),
        },
        _ => ty,
    }
}

crate fn strip_path(path: &Path) -> Path {
    let segments = path
        .segments
        .iter()
        .map(|s| PathSegment {
            name: s.name,
            args: GenericArgs::AngleBracketed { args: vec![], bindings: vec![] },
        })
        .collect();

    Path { global: path.global, res: path.res, segments }
}

crate fn qpath_to_string(p: &hir::QPath<'_>) -> String {
    let segments = match *p {
        hir::QPath::Resolved(_, ref path) => &path.segments,
        hir::QPath::TypeRelative(_, ref segment) => return segment.ident.to_string(),
        hir::QPath::LangItem(lang_item, ..) => return lang_item.name().to_string(),
    };

    let mut s = String::new();
    for (i, seg) in segments.iter().enumerate() {
        if i > 0 {
            s.push_str("::");
        }
        if seg.ident.name != kw::PathRoot {
            s.push_str(&seg.ident.as_str());
        }
    }
    s
}

crate fn build_deref_target_impls(cx: &mut DocContext<'_>, items: &[Item], ret: &mut Vec<Item>) {
    let tcx = cx.tcx;

    for item in items {
        let target = match *item.kind {
            ItemKind::TypedefItem(ref t, true) => &t.type_,
            _ => continue,
        };

        if let Some(prim) = target.primitive_type() {
            for &did in prim.impls(tcx).iter().filter(|did| !did.is_local()) {
                inline::build_impl(cx, None, did, None, ret);
            }
        } else if let ResolvedPath { did, .. } = *target {
            if !did.is_local() {
                inline::build_impls(cx, None, did, None, ret);
            }
        }
    }
}

crate trait ToSource {
    fn to_src(&self, cx: &DocContext<'_>) -> String;
}

impl ToSource for rustc_span::Span {
    fn to_src(&self, cx: &DocContext<'_>) -> String {
        debug!("converting span {:?} to snippet", self);
        let sn = match cx.sess().source_map().span_to_snippet(*self) {
            Ok(x) => x,
            Err(_) => String::new(),
        };
        debug!("got snippet {}", sn);
        sn
    }
}

crate fn name_from_pat(p: &hir::Pat<'_>) -> Symbol {
    use rustc_hir::*;
    debug!("trying to get a name from pattern: {:?}", p);

    Symbol::intern(&match p.kind {
        PatKind::Wild | PatKind::Struct(..) => return kw::Underscore,
        PatKind::Binding(_, _, ident, _) => return ident.name,
        PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p),
        PatKind::Or(ref pats) => pats
            .iter()
            .map(|p| name_from_pat(&**p).to_string())
            .collect::<Vec<String>>()
            .join(" | "),
        PatKind::Tuple(ref elts, _) => format!(
            "({})",
            elts.iter()
                .map(|p| name_from_pat(&**p).to_string())
                .collect::<Vec<String>>()
                .join(", ")
        ),
        PatKind::Box(ref p) => return name_from_pat(&**p),
        PatKind::Ref(ref p, _) => return name_from_pat(&**p),
        PatKind::Lit(..) => {
            warn!(
                "tried to get argument name from PatKind::Lit, which is silly in function arguments"
            );
            return Symbol::intern("()");
        }
        PatKind::Range(..) => return kw::Underscore,
        PatKind::Slice(ref begin, ref mid, ref end) => {
            let begin = begin.iter().map(|p| name_from_pat(&**p).to_string());
            let mid = mid.as_ref().map(|p| format!("..{}", name_from_pat(&**p))).into_iter();
            let end = end.iter().map(|p| name_from_pat(&**p).to_string());
            format!("[{}]", begin.chain(mid).chain(end).collect::<Vec<_>>().join(", "))
        }
    })
}

crate fn print_const(cx: &DocContext<'_>, n: &'tcx ty::Const<'_>) -> String {
    match n.val {
        ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) => {
            let mut s = if let Some(def) = def.as_local() {
                let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def.did);
                print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(hir_id))
            } else {
                inline::print_inlined_const(cx.tcx, def.did)
            };
            if let Some(promoted) = promoted {
                s.push_str(&format!("::{:?}", promoted))
            }
            s
        }
        _ => {
            let mut s = n.to_string();
            // array lengths are obviously usize
            if s.ends_with("_usize") {
                let n = s.len() - "_usize".len();
                s.truncate(n);
                if s.ends_with(": ") {
                    let n = s.len() - ": ".len();
                    s.truncate(n);
                }
            }
            s
        }
    }
}

crate fn print_evaluated_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<String> {
    tcx.const_eval_poly(def_id).ok().and_then(|val| {
        let ty = tcx.type_of(def_id);
        match (val, ty.kind()) {
            (_, &ty::Ref(..)) => None,
            (ConstValue::Scalar(_), &ty::Adt(_, _)) => None,
            (ConstValue::Scalar(_), _) => {
                let const_ = ty::Const::from_value(tcx, val, ty);
                Some(print_const_with_custom_print_scalar(tcx, const_))
            }
            _ => None,
        }
    })
}

fn format_integer_with_underscore_sep(num: &str) -> String {
    let num_chars: Vec<_> = num.chars().collect();
    let mut num_start_index = if num_chars.get(0) == Some(&'-') { 1 } else { 0 };
    let chunk_size = match num[num_start_index..].as_bytes() {
        [b'0', b'b' | b'x', ..] => {
            num_start_index += 2;
            4
        }
        [b'0', b'o', ..] => {
            num_start_index += 2;
            let remaining_chars = num_chars.len() - num_start_index;
            if remaining_chars <= 6 {
                // don't add underscores to Unix permissions like 0755 or 100755
                return num.to_string();
            }
            3
        }
        _ => 3,
    };

    num_chars[..num_start_index]
        .iter()
        .chain(num_chars[num_start_index..].rchunks(chunk_size).rev().intersperse(&['_']).flatten())
        .collect()
}

fn print_const_with_custom_print_scalar(tcx: TyCtxt<'_>, ct: &'tcx ty::Const<'tcx>) -> String {
    // Use a slightly different format for integer types which always shows the actual value.
    // For all other types, fallback to the original `pretty_print_const`.
    match (ct.val, ct.ty.kind()) {
        (ty::ConstKind::Value(ConstValue::Scalar(int)), ty::Uint(ui)) => {
            format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
        }
        (ty::ConstKind::Value(ConstValue::Scalar(int)), ty::Int(i)) => {
            let ty = tcx.lift(ct.ty).unwrap();
            let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size;
            let data = int.assert_bits(size);
            let sign_extended_data = size.sign_extend(data) as i128;

            format!(
                "{}{}",
                format_integer_with_underscore_sep(&sign_extended_data.to_string()),
                i.name_str()
            )
        }
        _ => ct.to_string(),
    }
}

crate fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
    if let hir::Node::Expr(expr) = tcx.hir().get(hir_id) {
        if let hir::ExprKind::Lit(_) = &expr.kind {
            return true;
        }

        if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind {
            if let hir::ExprKind::Lit(_) = &expr.kind {
                return true;
            }
        }
    }

    false
}

crate fn print_const_expr(tcx: TyCtxt<'_>, body: hir::BodyId) -> String {
    let hir = tcx.hir();
    let value = &hir.body(body).value;

    let snippet = if !value.span.from_expansion() {
        tcx.sess.source_map().span_to_snippet(value.span).ok()
    } else {
        None
    };

    snippet.unwrap_or_else(|| rustc_hir_pretty::id_to_string(&hir, body.hir_id))
}

/// Given a type Path, resolve it to a Type using the TyCtxt
crate fn resolve_type(cx: &mut DocContext<'_>, path: Path, id: hir::HirId) -> Type {
    debug!("resolve_type({:?},{:?})", path, id);

    let is_generic = match path.res {
        Res::PrimTy(p) => return Primitive(PrimitiveType::from(p)),
        Res::SelfTy(..) if path.segments.len() == 1 => {
            return Generic(kw::SelfUpper);
        }
        Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => {
            return Generic(Symbol::intern(&path.whole_name()));
        }
        Res::SelfTy(..) | Res::Def(DefKind::TyParam | DefKind::AssocTy, _) => true,
        _ => false,
    };
    let did = register_res(cx, path.res);
    ResolvedPath { path, param_names: None, did, is_generic }
}

crate fn get_auto_trait_and_blanket_impls(
    cx: &mut DocContext<'tcx>,
    item_def_id: DefId,
) -> impl Iterator<Item = Item> {
    let auto_impls = cx
        .sess()
        .prof
        .generic_activity("get_auto_trait_impls")
        .run(|| AutoTraitFinder::new(cx).get_auto_trait_impls(item_def_id));
    let blanket_impls = cx
        .sess()
        .prof
        .generic_activity("get_blanket_impls")
        .run(|| BlanketImplFinder { cx }.get_blanket_impls(item_def_id));
    auto_impls.into_iter().chain(blanket_impls)
}

crate fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
    debug!("register_res({:?})", res);

    let (did, kind) = match res {
        Res::Def(DefKind::Fn, i) => (i, ItemType::Function),
        Res::Def(DefKind::TyAlias, i) => (i, ItemType::Typedef),
        Res::Def(DefKind::Enum, i) => (i, ItemType::Enum),
        Res::Def(DefKind::Trait, i) => (i, ItemType::Trait),
        Res::Def(DefKind::AssocTy | DefKind::AssocFn | DefKind::AssocConst, i) => {
            (cx.tcx.parent(i).unwrap(), ItemType::Trait)
        }
        Res::Def(DefKind::Struct, i) => (i, ItemType::Struct),
        Res::Def(DefKind::Union, i) => (i, ItemType::Union),
        Res::Def(DefKind::Mod, i) => (i, ItemType::Module),
        Res::Def(DefKind::ForeignTy, i) => (i, ItemType::ForeignType),
        Res::Def(DefKind::Const, i) => (i, ItemType::Constant),
        Res::Def(DefKind::Static, i) => (i, ItemType::Static),
        Res::Def(DefKind::Variant, i) => {
            (cx.tcx.parent(i).expect("cannot get parent def id"), ItemType::Enum)
        }
        Res::Def(DefKind::Macro(mac_kind), i) => match mac_kind {
            MacroKind::Bang => (i, ItemType::Macro),
            MacroKind::Attr => (i, ItemType::ProcAttribute),
            MacroKind::Derive => (i, ItemType::ProcDerive),
        },
        Res::Def(DefKind::TraitAlias, i) => (i, ItemType::TraitAlias),
        Res::SelfTy(Some(def_id), _) => (def_id, ItemType::Trait),
        Res::SelfTy(_, Some((impl_def_id, _))) => return impl_def_id,
        _ => return res.def_id(),
    };
    if did.is_local() {
        return did;
    }
    inline::record_extern_fqn(cx, did, kind);
    if let ItemType::Trait = kind {
        inline::record_extern_trait(cx, did);
    }
    did
}

crate fn resolve_use_source(cx: &mut DocContext<'_>, path: Path) -> ImportSource {
    ImportSource {
        did: if path.res.opt_def_id().is_none() { None } else { Some(register_res(cx, path.res)) },
        path,
    }
}

crate fn enter_impl_trait<F, R>(cx: &mut DocContext<'_>, f: F) -> R
where
    F: FnOnce(&mut DocContext<'_>) -> R,
{
    let old_bounds = mem::take(&mut cx.impl_trait_bounds);
    let r = f(cx);
    assert!(cx.impl_trait_bounds.is_empty());
    cx.impl_trait_bounds = old_bounds;
    r
}

/// Find the nearest parent module of a [`DefId`].
crate fn find_nearest_parent_module(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
    if def_id.is_top_level_module() {
        // The crate root has no parent. Use it as the root instead.
        Some(def_id)
    } else {
        let mut current = def_id;
        // The immediate parent might not always be a module.
        // Find the first parent which is.
        while let Some(parent) = tcx.parent(current) {
            if tcx.def_kind(parent) == DefKind::Mod {
                return Some(parent);
            }
            current = parent;
        }
        None
    }
}

/// Checks for the existence of `hidden` in the attribute below if `flag` is `sym::hidden`:
///
/// ```
/// #[doc(hidden)]
/// pub fn foo() {}
/// ```
///
/// This function exists because it runs on `hir::Attributes` whereas the other is a
/// `clean::Attributes` method.
crate fn has_doc_flag(attrs: ty::Attributes<'_>, flag: Symbol) -> bool {
    attrs.iter().any(|attr| {
        attr.has_name(sym::doc)
            && attr.meta_item_list().map_or(false, |l| rustc_attr::list_contains_name(&l, flag))
    })
}