src/librustdoc/visit_ast.rs

   1 //! The Rust AST Visitor. Extracts useful information and massages it into a form
   2 //! usable for `clean`.
   3
   4 use rustc::hir::{self, Node};
   5 use rustc::hir::def::{Res, DefKind};
   6 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
   7 use rustc::middle::privacy::AccessLevel;
   8 use rustc::util::nodemap::{FxHashSet, FxHashMap};
   9 use syntax::ast;
  10 use syntax::attr;
  11 use syntax::ext::base::MacroKind;
  12 use syntax::source_map::Spanned;
  13 use syntax::symbol::sym;
  14 use syntax_pos::{self, Span};
  15
  16 use std::mem;
  17
  18 use crate::core;
  19 use crate::clean::{self, AttributesExt, NestedAttributesExt, def_id_to_path};
  20 use crate::doctree::*;
  21
  22
  23 // Looks to me like the first two of these are actually
  24 // output parameters, maybe only mutated once; perhaps
  25 // better simply to have the visit method return a tuple
  26 // containing them?
  27
  28 // Also, is there some reason that this doesn't use the 'visit'
  29 // framework from syntax?.
  30
  31 pub struct RustdocVisitor<'a, 'tcx> {
  32     pub module: Option<Module<'tcx>>,
  33     pub cx: &'a core::DocContext<'tcx>,
  34     view_item_stack: FxHashSet<hir::HirId>,
  35     inlining: bool,
  36     /// Are the current module and all of its parents public?
  37     inside_public_path: bool,
  38     exact_paths: Option<FxHashMap<DefId, Vec<String>>>,
  39 }
  40
  41 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
  42     pub fn new(
  43         cx: &'a core::DocContext<'tcx>
  44     ) -> RustdocVisitor<'a, 'tcx> {
  45         // If the root is re-exported, terminate all recursion.
  46         let mut stack = FxHashSet::default();
  47         stack.insert(hir::CRATE_HIR_ID);
  48         RustdocVisitor {
  49             module: None,
  50             cx,
  51             view_item_stack: stack,
  52             inlining: false,
  53             inside_public_path: true,
  54             exact_paths: Some(FxHashMap::default()),
  55         }
  56     }
  57
  58     fn store_path(&mut self, did: DefId) {
  59         // We can't use the entry API, as that keeps the mutable borrow of `self` active
  60         // when we try to use `cx`.
  61         let exact_paths = self.exact_paths.as_mut().unwrap();
  62         if exact_paths.get(&did).is_none() {
  63             let path = def_id_to_path(self.cx, did, self.cx.crate_name.clone());
  64             exact_paths.insert(did, path);
  65         }
  66     }
  67
  68     fn stability(&self, id: hir::HirId) -> Option<attr::Stability> {
  69         self.cx.tcx.hir().opt_local_def_id(id)
  70             .and_then(|def_id| self.cx.tcx.lookup_stability(def_id)).cloned()
  71     }
  72
  73     fn deprecation(&self, id: hir::HirId) -> Option<attr::Deprecation> {
  74         self.cx.tcx.hir().opt_local_def_id(id)
  75             .and_then(|def_id| self.cx.tcx.lookup_deprecation(def_id))
  76     }
  77
  78     pub fn visit(&mut self, krate: &'tcx hir::Crate) {
  79         let mut module = self.visit_mod_contents(krate.span,
  80                                               &krate.attrs,
  81                                               &Spanned { span: syntax_pos::DUMMY_SP,
  82                                                         node: hir::VisibilityKind::Public },
  83                                               hir::CRATE_HIR_ID,
  84                                               &krate.module,
  85                                               None);
  86         // Attach the crate's exported macros to the top-level module:
  87         module.macros.extend(
  88             krate.exported_macros.iter().map(|def| self.visit_local_macro(def, None)),
  89         );
  90         module.is_crate = true;
  91         self.module = Some(module);
  92
  93         self.cx.renderinfo.borrow_mut().exact_paths = self.exact_paths.take().unwrap();
  94     }
  95
  96     pub fn visit_variant_data(&mut self, item: &'tcx hir::Item,
  97                               name: ast::Name, sd: &'tcx hir::VariantData,
  98                               generics: &'tcx hir::Generics) -> Struct<'tcx> {
  99         debug!("visiting struct");
 100         let struct_type = struct_type_from_def(&*sd);
 101         Struct {
 102             id: item.hir_id,
 103             struct_type,
 104             name,
 105             vis: &item.vis,
 106             stab: self.stability(item.hir_id),
 107             depr: self.deprecation(item.hir_id),
 108             attrs: &item.attrs,
 109             generics,
 110             fields: sd.fields(),
 111             whence: item.span
 112         }
 113     }
 114
 115     pub fn visit_union_data(&mut self, item: &'tcx hir::Item,
 116                             name: ast::Name, sd: &'tcx hir::VariantData,
 117                             generics: &'tcx hir::Generics) -> Union<'tcx> {
 118         debug!("visiting union");
 119         let struct_type = struct_type_from_def(&*sd);
 120         Union {
 121             id: item.hir_id,
 122             struct_type,
 123             name,
 124             vis: &item.vis,
 125             stab: self.stability(item.hir_id),
 126             depr: self.deprecation(item.hir_id),
 127             attrs: &item.attrs,
 128             generics,
 129             fields: sd.fields(),
 130             whence: item.span
 131         }
 132     }
 133
 134     pub fn visit_enum_def(&mut self, it: &'tcx hir::Item,
 135                           name: ast::Name, def: &'tcx hir::EnumDef,
 136                           generics: &'tcx hir::Generics) -> Enum<'tcx> {
 137         debug!("visiting enum");
 138         Enum {
 139             name,
 140             variants: def.variants.iter().map(|v| Variant {
 141                 name: v.node.ident.name,
 142                 id: v.node.id,
 143                 attrs: &v.node.attrs,
 144                 stab: self.stability(v.node.id),
 145                 depr: self.deprecation(v.node.id),
 146                 def: &v.node.data,
 147                 whence: v.span,
 148             }).collect(),
 149             vis: &it.vis,
 150             stab: self.stability(it.hir_id),
 151             depr: self.deprecation(it.hir_id),
 152             generics,
 153             attrs: &it.attrs,
 154             id: it.hir_id,
 155             whence: it.span,
 156         }
 157     }
 158
 159     pub fn visit_fn(&mut self, om: &mut Module<'tcx>, item: &'tcx hir::Item,
 160                     name: ast::Name, decl: &'tcx hir::FnDecl,
 161                     header: hir::FnHeader,
 162                     generics: &'tcx hir::Generics,
 163                     body: hir::BodyId) {
 164         debug!("visiting fn");
 165         let macro_kind = item.attrs.iter().filter_map(|a| {
 166             if a.check_name(sym::proc_macro) {
 167                 Some(MacroKind::Bang)
 168             } else if a.check_name(sym::proc_macro_derive) {
 169                 Some(MacroKind::Derive)
 170             } else if a.check_name(sym::proc_macro_attribute) {
 171                 Some(MacroKind::Attr)
 172             } else {
 173                 None
 174             }
 175         }).next();
 176         match macro_kind {
 177             Some(kind) => {
 178                 let name = if kind == MacroKind::Derive {
 179                     item.attrs.lists(sym::proc_macro_derive)
 180                               .filter_map(|mi| mi.ident())
 181                               .next()
 182                               .expect("proc-macro derives require a name")
 183                               .name
 184                 } else {
 185                     name
 186                 };
 187
 188                 let mut helpers = Vec::new();
 189                 for mi in item.attrs.lists(sym::proc_macro_derive) {
 190                     if !mi.check_name(sym::attributes) {
 191                         continue;
 192                     }
 193
 194                     if let Some(list) = mi.meta_item_list() {
 195                         for inner_mi in list {
 196                             if let Some(ident) = inner_mi.ident() {
 197                                 helpers.push(ident.name);
 198                             }
 199                         }
 200                     }
 201                 }
 202
 203                 om.proc_macros.push(ProcMacro {
 204                     name,
 205                     id: item.hir_id,
 206                     kind,
 207                     helpers,
 208                     attrs: &item.attrs,
 209                     whence: item.span,
 210                     stab: self.stability(item.hir_id),
 211                     depr: self.deprecation(item.hir_id),
 212                 });
 213             }
 214             None => {
 215                 om.fns.push(Function {
 216                     id: item.hir_id,
 217                     vis: &item.vis,
 218                     stab: self.stability(item.hir_id),
 219                     depr: self.deprecation(item.hir_id),
 220                     attrs: &item.attrs,
 221                     decl,
 222                     name,
 223                     whence: item.span,
 224                     generics,
 225                     header,
 226                     body,
 227                 });
 228             }
 229         }
 230     }
 231
 232     pub fn visit_mod_contents(&mut self, span: Span, attrs: &'tcx hir::HirVec<ast::Attribute>,
 233                               vis: &'tcx hir::Visibility, id: hir::HirId,
 234                               m: &'tcx hir::Mod,
 235                               name: Option<ast::Name>) -> Module<'tcx> {
 236         let mut om = Module::new(name, attrs, vis);
 237         om.where_outer = span;
 238         om.where_inner = m.inner;
 239         om.stab = self.stability(id);
 240         om.depr = self.deprecation(id);
 241         om.id = self.cx.tcx.hir().hir_to_node_id(id);
 242         // Keep track of if there were any private modules in the path.
 243         let orig_inside_public_path = self.inside_public_path;
 244         self.inside_public_path &= vis.node.is_pub();
 245         for i in &m.item_ids {
 246             let item = self.cx.tcx.hir().expect_item(i.id);
 247             self.visit_item(item, None, &mut om);
 248         }
 249         self.inside_public_path = orig_inside_public_path;
 250         om
 251     }
 252
 253     /// Tries to resolve the target of a `pub use` statement and inlines the
 254     /// target if it is defined locally and would not be documented otherwise,
 255     /// or when it is specifically requested with `please_inline`.
 256     /// (the latter is the case when the import is marked `doc(inline)`)
 257     ///
 258     /// Cross-crate inlining occurs later on during crate cleaning
 259     /// and follows different rules.
 260     ///
 261     /// Returns `true` if the target has been inlined.
 262     fn maybe_inline_local(&mut self,
 263                           id: hir::HirId,
 264                           res: Res,
 265                           renamed: Option<ast::Ident>,
 266                           glob: bool,
 267                           om: &mut Module<'tcx>,
 268                           please_inline: bool) -> bool {
 269
 270         fn inherits_doc_hidden(cx: &core::DocContext<'_>, mut node: hir::HirId) -> bool {
 271             while let Some(id) = cx.tcx.hir().get_enclosing_scope(node) {
 272                 node = id;
 273                 if cx.tcx.hir().attrs(node)
 274                     .lists(sym::doc).has_word(sym::hidden) {
 275                     return true;
 276                 }
 277                 if node == hir::CRATE_HIR_ID {
 278                     break;
 279                 }
 280             }
 281             false
 282         }
 283
 284         debug!("maybe_inline_local res: {:?}", res);
 285
 286         let tcx = self.cx.tcx;
 287         let res_did = if let Some(did) = res.opt_def_id() {
 288             did
 289         } else {
 290             return false;
 291         };
 292
 293         let use_attrs = tcx.hir().attrs(id);
 294         // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
 295         let is_no_inline = use_attrs.lists(sym::doc).has_word(sym::no_inline) ||
 296                            use_attrs.lists(sym::doc).has_word(sym::hidden);
 297
 298         // For cross-crate impl inlining we need to know whether items are
 299         // reachable in documentation -- a previously nonreachable item can be
 300         // made reachable by cross-crate inlining which we're checking here.
 301         // (this is done here because we need to know this upfront).
 302         if !res_did.is_local() && !is_no_inline {
 303             let attrs = clean::inline::load_attrs(self.cx, res_did);
 304             let self_is_hidden = attrs.lists(sym::doc).has_word(sym::hidden);
 305             match res {
 306                 Res::Def(DefKind::Trait, did) |
 307                 Res::Def(DefKind::Struct, did) |
 308                 Res::Def(DefKind::Union, did) |
 309                 Res::Def(DefKind::Enum, did) |
 310                 Res::Def(DefKind::ForeignTy, did) |
 311                 Res::Def(DefKind::TyAlias, did) if !self_is_hidden => {
 312                     self.cx.renderinfo
 313                         .borrow_mut()
 314                         .access_levels.map
 315                         .insert(did, AccessLevel::Public);
 316                 },
 317                 Res::Def(DefKind::Mod, did) => if !self_is_hidden {
 318                     crate::visit_lib::LibEmbargoVisitor::new(self.cx).visit_mod(did);
 319                 },
 320                 _ => {},
 321             }
 322
 323             return false
 324         }
 325
 326         let res_hir_id = match tcx.hir().as_local_hir_id(res_did) {
 327             Some(n) => n, None => return false
 328         };
 329
 330         let is_private = !self.cx.renderinfo.borrow().access_levels.is_public(res_did);
 331         let is_hidden = inherits_doc_hidden(self.cx, res_hir_id);
 332
 333         // Only inline if requested or if the item would otherwise be stripped.
 334         if (!please_inline && !is_private && !is_hidden) || is_no_inline {
 335             return false
 336         }
 337
 338         if !self.view_item_stack.insert(res_hir_id) { return false }
 339
 340         let ret = match tcx.hir().get(res_hir_id) {
 341             Node::Item(&hir::Item { node: hir::ItemKind::Mod(ref m), .. }) if glob => {
 342                 let prev = mem::replace(&mut self.inlining, true);
 343                 for i in &m.item_ids {
 344                     let i = self.cx.tcx.hir().expect_item(i.id);
 345                     self.visit_item(i, None, om);
 346                 }
 347                 self.inlining = prev;
 348                 true
 349             }
 350             Node::Item(it) if !glob => {
 351                 let prev = mem::replace(&mut self.inlining, true);
 352                 self.visit_item(it, renamed, om);
 353                 self.inlining = prev;
 354                 true
 355             }
 356             Node::ForeignItem(it) if !glob => {
 357                 let prev = mem::replace(&mut self.inlining, true);
 358                 self.visit_foreign_item(it, renamed, om);
 359                 self.inlining = prev;
 360                 true
 361             }
 362             Node::MacroDef(def) if !glob => {
 363                 om.macros.push(self.visit_local_macro(def, renamed.map(|i| i.name)));
 364                 true
 365             }
 366             _ => false,
 367         };
 368         self.view_item_stack.remove(&res_hir_id);
 369         ret
 370     }
 371
 372     pub fn visit_item(&mut self, item: &'tcx hir::Item,
 373                       renamed: Option<ast::Ident>, om: &mut Module<'tcx>) {
 374         debug!("visiting item {:?}", item);
 375         let ident = renamed.unwrap_or(item.ident);
 376
 377         if item.vis.node.is_pub() {
 378             let def_id = self.cx.tcx.hir().local_def_id(item.hir_id);
 379             self.store_path(def_id);
 380         }
 381
 382         match item.node {
 383             hir::ItemKind::ForeignMod(ref fm) => {
 384                 for item in &fm.items {
 385                     self.visit_foreign_item(item, None, om);
 386                 }
 387             }
 388             // If we're inlining, skip private items.
 389             _ if self.inlining && !item.vis.node.is_pub() => {}
 390             hir::ItemKind::GlobalAsm(..) => {}
 391             hir::ItemKind::ExternCrate(orig_name) => {
 392                 let def_id = self.cx.tcx.hir().local_def_id(item.hir_id);
 393                 om.extern_crates.push(ExternCrate {
 394                     cnum: self.cx.tcx.extern_mod_stmt_cnum(def_id)
 395                                 .unwrap_or(LOCAL_CRATE),
 396                     name: ident.name,
 397                     path: orig_name.map(|x|x.to_string()),
 398                     vis: &item.vis,
 399                     attrs: &item.attrs,
 400                     whence: item.span,
 401                 })
 402             }
 403             hir::ItemKind::Use(_, hir::UseKind::ListStem) => {}
 404             hir::ItemKind::Use(ref path, kind) => {
 405                 let is_glob = kind == hir::UseKind::Glob;
 406
 407                 // Struct and variant constructors and proc macro stubs always show up alongside
 408                 // their definitions, we've already processed them so just discard these.
 409                 if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
 410                     return;
 411                 }
 412
 413                 // If there was a private module in the current path then don't bother inlining
 414                 // anything as it will probably be stripped anyway.
 415                 if item.vis.node.is_pub() && self.inside_public_path {
 416                     let please_inline = item.attrs.iter().any(|item| {
 417                         match item.meta_item_list() {
 418                             Some(ref list) if item.check_name(sym::doc) => {
 419                                 list.iter().any(|i| i.check_name(sym::inline))
 420                             }
 421                             _ => false,
 422                         }
 423                     });
 424                     let ident = if is_glob { None } else { Some(ident) };
 425                     if self.maybe_inline_local(item.hir_id,
 426                                                path.res,
 427                                                ident,
 428                                                is_glob,
 429                                                om,
 430                                                please_inline) {
 431                         return;
 432                     }
 433                 }
 434
 435                 om.imports.push(Import {
 436                     name: ident.name,
 437                     id: item.hir_id,
 438                     vis: &item.vis,
 439                     attrs: &item.attrs,
 440                     path,
 441                     glob: is_glob,
 442                     whence: item.span,
 443                 });
 444             }
 445             hir::ItemKind::Mod(ref m) => {
 446                 om.mods.push(self.visit_mod_contents(item.span,
 447                                                      &item.attrs,
 448                                                      &item.vis,
 449                                                      item.hir_id,
 450                                                      m,
 451                                                      Some(ident.name)));
 452             },
 453             hir::ItemKind::Enum(ref ed, ref gen) =>
 454                 om.enums.push(self.visit_enum_def(item, ident.name, ed, gen)),
 455             hir::ItemKind::Struct(ref sd, ref gen) =>
 456                 om.structs.push(self.visit_variant_data(item, ident.name, sd, gen)),
 457             hir::ItemKind::Union(ref sd, ref gen) =>
 458                 om.unions.push(self.visit_union_data(item, ident.name, sd, gen)),
 459             hir::ItemKind::Fn(ref fd, header, ref gen, body) =>
 460                 self.visit_fn(om, item, ident.name, &**fd, header, gen, body),
 461             hir::ItemKind::Ty(ref ty, ref gen) => {
 462                 let t = Typedef {
 463                     ty,
 464                     gen,
 465                     name: ident.name,
 466                     id: item.hir_id,
 467                     attrs: &item.attrs,
 468                     whence: item.span,
 469                     vis: &item.vis,
 470                     stab: self.stability(item.hir_id),
 471                     depr: self.deprecation(item.hir_id),
 472                 };
 473                 om.typedefs.push(t);
 474             },
 475             hir::ItemKind::Existential(ref exist_ty) => {
 476                 let t = Existential {
 477                     exist_ty,
 478                     name: ident.name,
 479                     id: item.hir_id,
 480                     attrs: &item.attrs,
 481                     whence: item.span,
 482                     vis: &item.vis,
 483                     stab: self.stability(item.hir_id),
 484                     depr: self.deprecation(item.hir_id),
 485                 };
 486                 om.existentials.push(t);
 487             },
 488             hir::ItemKind::Static(ref type_, mutability, expr) => {
 489                 let s = Static {
 490                     type_,
 491                     mutability,
 492                     expr,
 493                     id: item.hir_id,
 494                     name: ident.name,
 495                     attrs: &item.attrs,
 496                     whence: item.span,
 497                     vis: &item.vis,
 498                     stab: self.stability(item.hir_id),
 499                     depr: self.deprecation(item.hir_id),
 500                 };
 501                 om.statics.push(s);
 502             },
 503             hir::ItemKind::Const(ref type_, expr) => {
 504                 let s = Constant {
 505                     type_,
 506                     expr,
 507                     id: item.hir_id,
 508                     name: ident.name,
 509                     attrs: &item.attrs,
 510                     whence: item.span,
 511                     vis: &item.vis,
 512                     stab: self.stability(item.hir_id),
 513                     depr: self.deprecation(item.hir_id),
 514                 };
 515                 om.constants.push(s);
 516             },
 517             hir::ItemKind::Trait(is_auto, unsafety, ref generics, ref bounds, ref item_ids) => {
 518                 let items = item_ids.iter()
 519                                     .map(|ti| self.cx.tcx.hir().trait_item(ti.id))
 520                                     .collect();
 521                 let t = Trait {
 522                     is_auto,
 523                     unsafety,
 524                     name: ident.name,
 525                     items,
 526                     generics,
 527                     bounds,
 528                     id: item.hir_id,
 529                     attrs: &item.attrs,
 530                     whence: item.span,
 531                     vis: &item.vis,
 532                     stab: self.stability(item.hir_id),
 533                     depr: self.deprecation(item.hir_id),
 534                 };
 535                 om.traits.push(t);
 536             },
 537             hir::ItemKind::TraitAlias(ref generics, ref bounds) => {
 538                 let t = TraitAlias {
 539                     name: ident.name,
 540                     generics,
 541                     bounds,
 542                     id: item.hir_id,
 543                     attrs: &item.attrs,
 544                     whence: item.span,
 545                     vis: &item.vis,
 546                     stab: self.stability(item.hir_id),
 547                     depr: self.deprecation(item.hir_id),
 548                 };
 549                 om.trait_aliases.push(t);
 550             },
 551
 552             hir::ItemKind::Impl(unsafety,
 553                           polarity,
 554                           defaultness,
 555                           ref generics,
 556                           ref trait_,
 557                           ref for_,
 558                           ref item_ids) => {
 559                 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
 560                 // them up regardless of where they're located.
 561                 if !self.inlining && trait_.is_none() {
 562                     let items = item_ids.iter()
 563                                         .map(|ii| self.cx.tcx.hir().impl_item(ii.id))
 564                                         .collect();
 565                     let i = Impl {
 566                         unsafety,
 567                         polarity,
 568                         defaultness,
 569                         generics,
 570                         trait_,
 571                         for_,
 572                         items,
 573                         attrs: &item.attrs,
 574                         id: item.hir_id,
 575                         whence: item.span,
 576                         vis: &item.vis,
 577                         stab: self.stability(item.hir_id),
 578                         depr: self.deprecation(item.hir_id),
 579                     };
 580                     om.impls.push(i);
 581                 }
 582             },
 583         }
 584     }
 585
 586     fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem,
 587                       renamed: Option<ast::Ident>, om: &mut Module<'tcx>) {
 588         // If inlining we only want to include public functions.
 589         if self.inlining && !item.vis.node.is_pub() {
 590             return;
 591         }
 592
 593         om.foreigns.push(ForeignItem {
 594             id: item.hir_id,
 595             name: renamed.unwrap_or(item.ident).name,
 596             kind: &item.node,
 597             vis: &item.vis,
 598             stab: self.stability(item.hir_id),
 599             depr: self.deprecation(item.hir_id),
 600             attrs: &item.attrs,
 601             whence: item.span
 602         });
 603     }
 604
 605     // Convert each `exported_macro` into a doc item.
 606     fn visit_local_macro(
 607         &self,
 608         def: &'tcx hir::MacroDef,
 609         renamed: Option<ast::Name>
 610     ) -> Macro<'tcx> {
 611         debug!("visit_local_macro: {}", def.name);
 612         let tts = def.body.trees().collect::<Vec<_>>();
 613         // Extract the spans of all matchers. They represent the "interface" of the macro.
 614         let matchers = tts.chunks(4).map(|arm| arm[0].span()).collect();
 615
 616         Macro {
 617
 618             def_id: self.cx.tcx.hir().local_def_id(def.hir_id),
 619             attrs: &def.attrs,
 620             name: renamed.unwrap_or(def.name),
 621             whence: def.span,
 622             matchers,
 623             stab: self.stability(def.hir_id),
 624             depr: self.deprecation(def.hir_id),
 625             imported_from: None,
 626         }
 627     }
 628 }