src/librustdoc/clean/inline.rs

   1 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! Support for inlining external documentation into the current AST.
  12
  13 use std::collections::BTreeMap;
  14 use std::io;
  15 use std::iter::once;
  16 use std::rc::Rc;
  17
  18 use syntax::ast;
  19 use rustc::hir;
  20
  21 use rustc::hir::def::{Def, CtorKind};
  22 use rustc::hir::def_id::DefId;
  23 use rustc::ty;
  24 use rustc::util::nodemap::FxHashSet;
  25
  26 use core::{DocContext, DocAccessLevels};
  27 use doctree;
  28 use clean::{self, GetDefId};
  29
  30 use super::Clean;
  31
  32 /// Attempt to inline a definition into this AST.
  33 ///
  34 /// This function will fetch the definition specified, and if it is
  35 /// from another crate it will attempt to inline the documentation
  36 /// from the other crate into this crate.
  37 ///
  38 /// This is primarily used for `pub use` statements which are, in general,
  39 /// implementation details. Inlining the documentation should help provide a
  40 /// better experience when reading the documentation in this use case.
  41 ///
  42 /// The returned value is `None` if the definition could not be inlined,
  43 /// and `Some` of a vector of items if it was successfully expanded.
  44 pub fn try_inline(cx: &DocContext, def: Def, name: ast::Name)
  45                   -> Option<Vec<clean::Item>> {
  46     if def == Def::Err { return None }
  47     let did = def.def_id();
  48     if did.is_local() { return None }
  49     let mut ret = Vec::new();
  50     let inner = match def {
  51         Def::Trait(did) => {
  52             record_extern_fqn(cx, did, clean::TypeKind::Trait);
  53             ret.extend(build_impls(cx, did));
  54             clean::TraitItem(build_external_trait(cx, did))
  55         }
  56         Def::Fn(did) => {
  57             record_extern_fqn(cx, did, clean::TypeKind::Function);
  58             clean::FunctionItem(build_external_function(cx, did))
  59         }
  60         Def::Struct(did) => {
  61             record_extern_fqn(cx, did, clean::TypeKind::Struct);
  62             ret.extend(build_impls(cx, did));
  63             clean::StructItem(build_struct(cx, did))
  64         }
  65         Def::Union(did) => {
  66             record_extern_fqn(cx, did, clean::TypeKind::Union);
  67             ret.extend(build_impls(cx, did));
  68             clean::UnionItem(build_union(cx, did))
  69         }
  70         Def::TyAlias(did) => {
  71             record_extern_fqn(cx, did, clean::TypeKind::Typedef);
  72             ret.extend(build_impls(cx, did));
  73             clean::TypedefItem(build_type_alias(cx, did), false)
  74         }
  75         Def::Enum(did) => {
  76             record_extern_fqn(cx, did, clean::TypeKind::Enum);
  77             ret.extend(build_impls(cx, did));
  78             clean::EnumItem(build_enum(cx, did))
  79         }
  80         Def::TyForeign(did) => {
  81             record_extern_fqn(cx, did, clean::TypeKind::Foreign);
  82             ret.extend(build_impls(cx, did));
  83             clean::ForeignTypeItem
  84         }
  85         // Never inline enum variants but leave them shown as reexports.
  86         Def::Variant(..) => return None,
  87         // Assume that enum variants and struct types are reexported next to
  88         // their constructors.
  89         Def::VariantCtor(..) |
  90         Def::StructCtor(..) => return Some(Vec::new()),
  91         Def::Mod(did) => {
  92             record_extern_fqn(cx, did, clean::TypeKind::Module);
  93             clean::ModuleItem(build_module(cx, did))
  94         }
  95         Def::Static(did, mtbl) => {
  96             record_extern_fqn(cx, did, clean::TypeKind::Static);
  97             clean::StaticItem(build_static(cx, did, mtbl))
  98         }
  99         Def::Const(did) => {
 100             record_extern_fqn(cx, did, clean::TypeKind::Const);
 101             clean::ConstantItem(build_const(cx, did))
 102         }
 103         _ => return None,
 104     };
 105     cx.renderinfo.borrow_mut().inlined.insert(did);
 106     ret.push(clean::Item {
 107         source: cx.tcx.def_span(did).clean(cx),
 108         name: Some(name.clean(cx)),
 109         attrs: load_attrs(cx, did),
 110         inner,
 111         visibility: Some(clean::Public),
 112         stability: cx.tcx.lookup_stability(did).clean(cx),
 113         deprecation: cx.tcx.lookup_deprecation(did).clean(cx),
 114         def_id: did,
 115     });
 116     Some(ret)
 117 }
 118
 119 pub fn load_attrs(cx: &DocContext, did: DefId) -> clean::Attributes {
 120     cx.tcx.get_attrs(did).clean(cx)
 121 }
 122
 123 /// Record an external fully qualified name in the external_paths cache.
 124 ///
 125 /// These names are used later on by HTML rendering to generate things like
 126 /// source links back to the original item.
 127 pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
 128     let crate_name = cx.tcx.crate_name(did.krate).to_string();
 129     let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
 130         // extern blocks have an empty name
 131         let s = elem.data.to_string();
 132         if !s.is_empty() {
 133             Some(s)
 134         } else {
 135             None
 136         }
 137     });
 138     let fqn = once(crate_name).chain(relative).collect();
 139     cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
 140 }
 141
 142 pub fn build_external_trait(cx: &DocContext, did: DefId) -> clean::Trait {
 143     let trait_items = cx.tcx.associated_items(did).map(|item| item.clean(cx)).collect();
 144     let predicates = cx.tcx.predicates_of(did);
 145     let generics = (cx.tcx.generics_of(did), &predicates).clean(cx);
 146     let generics = filter_non_trait_generics(did, generics);
 147     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
 148     let is_spotlight = load_attrs(cx, did).has_doc_flag("spotlight");
 149     clean::Trait {
 150         unsafety: cx.tcx.trait_def(did).unsafety,
 151         generics,
 152         items: trait_items,
 153         bounds: supertrait_bounds,
 154         is_spotlight,
 155     }
 156 }
 157
 158 fn build_external_function(cx: &DocContext, did: DefId) -> clean::Function {
 159     let sig = cx.tcx.fn_sig(did);
 160
 161     let constness = if cx.tcx.is_const_fn(did) {
 162         hir::Constness::Const
 163     } else {
 164         hir::Constness::NotConst
 165     };
 166
 167     let predicates = cx.tcx.predicates_of(did);
 168     clean::Function {
 169         decl: (did, sig).clean(cx),
 170         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 171         unsafety: sig.unsafety(),
 172         constness,
 173         abi: sig.abi(),
 174     }
 175 }
 176
 177 fn build_enum(cx: &DocContext, did: DefId) -> clean::Enum {
 178     let predicates = cx.tcx.predicates_of(did);
 179
 180     clean::Enum {
 181         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 182         variants_stripped: false,
 183         variants: cx.tcx.adt_def(did).variants.clean(cx),
 184     }
 185 }
 186
 187 fn build_struct(cx: &DocContext, did: DefId) -> clean::Struct {
 188     let predicates = cx.tcx.predicates_of(did);
 189     let variant = cx.tcx.adt_def(did).struct_variant();
 190
 191     clean::Struct {
 192         struct_type: match variant.ctor_kind {
 193             CtorKind::Fictive => doctree::Plain,
 194             CtorKind::Fn => doctree::Tuple,
 195             CtorKind::Const => doctree::Unit,
 196         },
 197         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 198         fields: variant.fields.clean(cx),
 199         fields_stripped: false,
 200     }
 201 }
 202
 203 fn build_union(cx: &DocContext, did: DefId) -> clean::Union {
 204     let predicates = cx.tcx.predicates_of(did);
 205     let variant = cx.tcx.adt_def(did).struct_variant();
 206
 207     clean::Union {
 208         struct_type: doctree::Plain,
 209         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 210         fields: variant.fields.clean(cx),
 211         fields_stripped: false,
 212     }
 213 }
 214
 215 fn build_type_alias(cx: &DocContext, did: DefId) -> clean::Typedef {
 216     let predicates = cx.tcx.predicates_of(did);
 217
 218     clean::Typedef {
 219         type_: cx.tcx.type_of(did).clean(cx),
 220         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 221     }
 222 }
 223
 224 pub fn build_impls(cx: &DocContext, did: DefId) -> Vec<clean::Item> {
 225     let tcx = cx.tcx;
 226     let mut impls = Vec::new();
 227
 228     for &did in tcx.inherent_impls(did).iter() {
 229         build_impl(cx, did, &mut impls);
 230     }
 231
 232     // If this is the first time we've inlined something from another crate, then
 233     // we inline *all* impls from all the crates into this crate. Note that there's
 234     // currently no way for us to filter this based on type, and we likely need
 235     // many impls for a variety of reasons.
 236     //
 237     // Primarily, the impls will be used to populate the documentation for this
 238     // type being inlined, but impls can also be used when generating
 239     // documentation for primitives (no way to find those specifically).
 240     if cx.populated_all_crate_impls.get() {
 241         return impls;
 242     }
 243
 244     cx.populated_all_crate_impls.set(true);
 245
 246     for &cnum in tcx.crates().iter() {
 247         for did in tcx.all_trait_implementations(cnum).iter() {
 248             build_impl(cx, *did, &mut impls);
 249         }
 250     }
 251
 252     // Also try to inline primitive impls from other crates.
 253     let lang_items = tcx.lang_items();
 254     let primitive_impls = [
 255         lang_items.isize_impl(),
 256         lang_items.i8_impl(),
 257         lang_items.i16_impl(),
 258         lang_items.i32_impl(),
 259         lang_items.i64_impl(),
 260         lang_items.i128_impl(),
 261         lang_items.usize_impl(),
 262         lang_items.u8_impl(),
 263         lang_items.u16_impl(),
 264         lang_items.u32_impl(),
 265         lang_items.u64_impl(),
 266         lang_items.u128_impl(),
 267         lang_items.f32_impl(),
 268         lang_items.f64_impl(),
 269         lang_items.char_impl(),
 270         lang_items.str_impl(),
 271         lang_items.slice_impl(),
 272         lang_items.const_ptr_impl(),
 273         lang_items.mut_ptr_impl(),
 274     ];
 275
 276     for def_id in primitive_impls.iter().filter_map(|&def_id| def_id) {
 277         if !def_id.is_local() {
 278             build_impl(cx, def_id, &mut impls);
 279         }
 280     }
 281
 282     impls
 283 }
 284
 285 pub fn build_impl(cx: &DocContext, did: DefId, ret: &mut Vec<clean::Item>) {
 286     if !cx.renderinfo.borrow_mut().inlined.insert(did) {
 287         return
 288     }
 289
 290     let attrs = load_attrs(cx, did);
 291     let tcx = cx.tcx;
 292     let associated_trait = tcx.impl_trait_ref(did);
 293
 294     // Only inline impl if the implemented trait is
 295     // reachable in rustdoc generated documentation
 296     if let Some(traitref) = associated_trait {
 297         if !cx.access_levels.borrow().is_doc_reachable(traitref.def_id) {
 298             return
 299         }
 300     }
 301
 302     // If this is an auto impl, then bail out early here
 303     if tcx.is_auto_impl(did) {
 304         return ret.push(clean::Item {
 305             inner: clean::AutoImplItem(clean::AutoImpl {
 306                 // FIXME: this should be decoded
 307                 unsafety: hir::Unsafety::Normal,
 308                 trait_: match associated_trait.as_ref().unwrap().clean(cx) {
 309                     clean::TraitBound(polyt, _) => polyt.trait_,
 310                     clean::RegionBound(..) => unreachable!(),
 311                 },
 312             }),
 313             source: tcx.def_span(did).clean(cx),
 314             name: None,
 315             attrs,
 316             visibility: Some(clean::Inherited),
 317             stability: tcx.lookup_stability(did).clean(cx),
 318             deprecation: tcx.lookup_deprecation(did).clean(cx),
 319             def_id: did,
 320         });
 321     }
 322
 323     let for_ = tcx.type_of(did).clean(cx);
 324
 325     // Only inline impl if the implementing type is
 326     // reachable in rustdoc generated documentation
 327     if let Some(did) = for_.def_id() {
 328         if !cx.access_levels.borrow().is_doc_reachable(did) {
 329             return
 330         }
 331     }
 332
 333     let predicates = tcx.predicates_of(did);
 334     let trait_items = tcx.associated_items(did).filter_map(|item| {
 335         match item.kind {
 336             ty::AssociatedKind::Const => {
 337                 let default = if item.defaultness.has_value() {
 338                     Some(print_inlined_const(cx, item.def_id))
 339                 } else {
 340                     None
 341                 };
 342                 Some(clean::Item {
 343                     name: Some(item.name.clean(cx)),
 344                     inner: clean::AssociatedConstItem(
 345                         tcx.type_of(item.def_id).clean(cx),
 346                         default,
 347                     ),
 348                     source: tcx.def_span(item.def_id).clean(cx),
 349                     attrs: clean::Attributes::default(),
 350                     visibility: None,
 351                     stability: tcx.lookup_stability(item.def_id).clean(cx),
 352                     deprecation: tcx.lookup_deprecation(item.def_id).clean(cx),
 353                     def_id: item.def_id
 354                 })
 355             }
 356             ty::AssociatedKind::Method => {
 357                 if item.vis != ty::Visibility::Public && associated_trait.is_none() {
 358                     return None
 359                 }
 360                 let mut cleaned = item.clean(cx);
 361                 cleaned.inner = match cleaned.inner.clone() {
 362                     clean::TyMethodItem(clean::TyMethod {
 363                         unsafety, decl, generics, abi
 364                     }) => {
 365                         let constness = if tcx.is_const_fn(item.def_id) {
 366                             hir::Constness::Const
 367                         } else {
 368                             hir::Constness::NotConst
 369                         };
 370
 371                         clean::MethodItem(clean::Method {
 372                             unsafety,
 373                             constness,
 374                             decl,
 375                             generics,
 376                             abi,
 377                         })
 378                     }
 379                     ref r => panic!("not a tymethod: {:?}", r),
 380                 };
 381                 Some(cleaned)
 382             }
 383             ty::AssociatedKind::Type => {
 384                 let typedef = clean::Typedef {
 385                     type_: tcx.type_of(item.def_id).clean(cx),
 386                     generics: clean::Generics {
 387                         lifetimes: vec![],
 388                         type_params: vec![],
 389                         where_predicates: vec![]
 390                     }
 391                 };
 392                 Some(clean::Item {
 393                     name: Some(item.name.clean(cx)),
 394                     inner: clean::TypedefItem(typedef, true),
 395                     source: tcx.def_span(item.def_id).clean(cx),
 396                     attrs: clean::Attributes::default(),
 397                     visibility: None,
 398                     stability: tcx.lookup_stability(item.def_id).clean(cx),
 399                     deprecation: tcx.lookup_deprecation(item.def_id).clean(cx),
 400                     def_id: item.def_id
 401                 })
 402             }
 403         }
 404     }).collect::<Vec<_>>();
 405     let polarity = tcx.impl_polarity(did);
 406     let trait_ = associated_trait.clean(cx).map(|bound| {
 407         match bound {
 408             clean::TraitBound(polyt, _) => polyt.trait_,
 409             clean::RegionBound(..) => unreachable!(),
 410         }
 411     });
 412     if trait_.def_id() == tcx.lang_items().deref_trait() {
 413         super::build_deref_target_impls(cx, &trait_items, ret);
 414     }
 415
 416     let provided = trait_.def_id().map(|did| {
 417         tcx.provided_trait_methods(did)
 418             .into_iter()
 419             .map(|meth| meth.name.to_string())
 420             .collect()
 421     }).unwrap_or(FxHashSet());
 422
 423     ret.push(clean::Item {
 424         inner: clean::ImplItem(clean::Impl {
 425             unsafety: hir::Unsafety::Normal, // FIXME: this should be decoded
 426             provided_trait_methods: provided,
 427             trait_,
 428             for_,
 429             generics: (tcx.generics_of(did), &predicates).clean(cx),
 430             items: trait_items,
 431             polarity: Some(polarity.clean(cx)),
 432         }),
 433         source: tcx.def_span(did).clean(cx),
 434         name: None,
 435         attrs,
 436         visibility: Some(clean::Inherited),
 437         stability: tcx.lookup_stability(did).clean(cx),
 438         deprecation: tcx.lookup_deprecation(did).clean(cx),
 439         def_id: did,
 440     });
 441 }
 442
 443 fn build_module(cx: &DocContext, did: DefId) -> clean::Module {
 444     let mut items = Vec::new();
 445     fill_in(cx, did, &mut items);
 446     return clean::Module {
 447         items,
 448         is_crate: false,
 449     };
 450
 451     fn fill_in(cx: &DocContext, did: DefId, items: &mut Vec<clean::Item>) {
 452         // If we're reexporting a reexport it may actually reexport something in
 453         // two namespaces, so the target may be listed twice. Make sure we only
 454         // visit each node at most once.
 455         let mut visited = FxHashSet();
 456         for &item in cx.tcx.item_children(did).iter() {
 457             let def_id = item.def.def_id();
 458             if cx.tcx.visibility(def_id) == ty::Visibility::Public {
 459                 if !visited.insert(def_id) { continue }
 460                 if let Some(i) = try_inline(cx, item.def, item.ident.name) {
 461                     items.extend(i)
 462                 }
 463             }
 464         }
 465     }
 466 }
 467
 468 struct InlinedConst {
 469     nested_bodies: Rc<BTreeMap<hir::BodyId, hir::Body>>
 470 }
 471
 472 impl hir::print::PpAnn for InlinedConst {
 473     fn nested(&self, state: &mut hir::print::State, nested: hir::print::Nested)
 474               -> io::Result<()> {
 475         if let hir::print::Nested::Body(body) = nested {
 476             state.print_expr(&self.nested_bodies[&body].value)
 477         } else {
 478             Ok(())
 479         }
 480     }
 481 }
 482
 483 pub fn print_inlined_const(cx: &DocContext, did: DefId) -> String {
 484     let body = cx.tcx.extern_const_body(did).body;
 485     let inlined = InlinedConst {
 486         nested_bodies: cx.tcx.item_body_nested_bodies(did).nested_bodies
 487     };
 488     hir::print::to_string(&inlined, |s| s.print_expr(&body.value))
 489 }
 490
 491 fn build_const(cx: &DocContext, did: DefId) -> clean::Constant {
 492     clean::Constant {
 493         type_: cx.tcx.type_of(did).clean(cx),
 494         expr: print_inlined_const(cx, did)
 495     }
 496 }
 497
 498 fn build_static(cx: &DocContext, did: DefId, mutable: bool) -> clean::Static {
 499     clean::Static {
 500         type_: cx.tcx.type_of(did).clean(cx),
 501         mutability: if mutable {clean::Mutable} else {clean::Immutable},
 502         expr: "\n\n\n".to_string(), // trigger the "[definition]" links
 503     }
 504 }
 505
 506 /// A trait's generics clause actually contains all of the predicates for all of
 507 /// its associated types as well. We specifically move these clauses to the
 508 /// associated types instead when displaying, so when we're generating the
 509 /// generics for the trait itself we need to be sure to remove them.
 510 /// We also need to remove the implied "recursive" Self: Trait bound.
 511 ///
 512 /// The inverse of this filtering logic can be found in the `Clean`
 513 /// implementation for `AssociatedType`
 514 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics)
 515                              -> clean::Generics {
 516     for pred in &mut g.where_predicates {
 517         match *pred {
 518             clean::WherePredicate::BoundPredicate {
 519                 ty: clean::Generic(ref s),
 520                 ref mut bounds
 521             } if *s == "Self" => {
 522                 bounds.retain(|bound| {
 523                     match *bound {
 524                         clean::TyParamBound::TraitBound(clean::PolyTrait {
 525                             trait_: clean::ResolvedPath { did, .. },
 526                             ..
 527                         }, _) => did != trait_did,
 528                         _ => true
 529                     }
 530                 });
 531             }
 532             _ => {}
 533         }
 534     }
 535
 536     g.where_predicates.retain(|pred| {
 537         match *pred {
 538             clean::WherePredicate::BoundPredicate {
 539                 ty: clean::QPath {
 540                     self_type: box clean::Generic(ref s),
 541                     trait_: box clean::ResolvedPath { did, .. },
 542                     name: ref _name,
 543                 }, ref bounds
 544             } => !(*s == "Self" && did == trait_did) && !bounds.is_empty(),
 545             _ => true,
 546         }
 547     });
 548     g
 549 }
 550
 551 /// Supertrait bounds for a trait are also listed in the generics coming from
 552 /// the metadata for a crate, so we want to separate those out and create a new
 553 /// list of explicit supertrait bounds to render nicely.
 554 fn separate_supertrait_bounds(mut g: clean::Generics)
 555                               -> (clean::Generics, Vec<clean::TyParamBound>) {
 556     let mut ty_bounds = Vec::new();
 557     g.where_predicates.retain(|pred| {
 558         match *pred {
 559             clean::WherePredicate::BoundPredicate {
 560                 ty: clean::Generic(ref s),
 561                 ref bounds
 562             } if *s == "Self" => {
 563                 ty_bounds.extend(bounds.iter().cloned());
 564                 false
 565             }
 566             _ => true,
 567         }
 568     });
 569     (g, ty_bounds)
 570 }