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