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::HashSet;
  14
  15 use syntax::ast;
  16 use syntax::attr::AttrMetaMethods;
  17 use rustc_front::hir;
  18
  19 use rustc::metadata::csearch;
  20 use rustc::metadata::decoder;
  21 use rustc::middle::def;
  22 use rustc::middle::def_id::DefId;
  23 use rustc::middle::ty;
  24 use rustc::middle::subst;
  25 use rustc::middle::stability;
  26 use rustc::middle::const_eval;
  27
  28 use core::DocContext;
  29 use doctree;
  30 use clean;
  31
  32 use super::{Clean, ToSource};
  33
  34 /// Attempt to inline the definition of a local node id into this AST.
  35 ///
  36 /// This function will fetch the definition of the id specified, and if it is
  37 /// from another crate it will attempt to inline the documentation from the
  38 /// other crate into this crate.
  39 ///
  40 /// This is primarily used for `pub use` statements which are, in general,
  41 /// implementation details. Inlining the documentation should help provide a
  42 /// better experience when reading the documentation in this use case.
  43 ///
  44 /// The returned value is `None` if the `id` could not be inlined, and `Some`
  45 /// of a vector of items if it was successfully expanded.
  46 pub fn try_inline(cx: &DocContext, id: ast::NodeId, into: Option<ast::Name>)
  47                   -> Option<Vec<clean::Item>> {
  48     let tcx = match cx.tcx_opt() {
  49         Some(tcx) => tcx,
  50         None => return None,
  51     };
  52     let def = match tcx.def_map.borrow().get(&id) {
  53         Some(d) => d.full_def(),
  54         None => return None,
  55     };
  56     let did = def.def_id();
  57     if did.is_local() { return None }
  58     try_inline_def(cx, tcx, def).map(|vec| {
  59         vec.into_iter().map(|mut item| {
  60             match into {
  61                 Some(into) if item.name.is_some() => {
  62                     item.name = Some(into.clean(cx));
  63                 }
  64                 _ => {}
  65             }
  66             item
  67         }).collect()
  68     })
  69 }
  70
  71 fn try_inline_def(cx: &DocContext, tcx: &ty::ctxt,
  72                   def: def::Def) -> Option<Vec<clean::Item>> {
  73     let mut ret = Vec::new();
  74     let did = def.def_id();
  75     let inner = match def {
  76         def::DefTrait(did) => {
  77             record_extern_fqn(cx, did, clean::TypeTrait);
  78             clean::TraitItem(build_external_trait(cx, tcx, did))
  79         }
  80         def::DefFn(did, false) => {
  81             // If this function is a tuple struct constructor, we just skip it
  82             record_extern_fqn(cx, did, clean::TypeFunction);
  83             clean::FunctionItem(build_external_function(cx, tcx, did))
  84         }
  85         def::DefStruct(did) => {
  86             record_extern_fqn(cx, did, clean::TypeStruct);
  87             ret.extend(build_impls(cx, tcx, did));
  88             clean::StructItem(build_struct(cx, tcx, did))
  89         }
  90         def::DefTy(did, false) => {
  91             record_extern_fqn(cx, did, clean::TypeTypedef);
  92             ret.extend(build_impls(cx, tcx, did));
  93             build_type(cx, tcx, did)
  94         }
  95         def::DefTy(did, true) => {
  96             record_extern_fqn(cx, did, clean::TypeEnum);
  97             ret.extend(build_impls(cx, tcx, did));
  98             build_type(cx, tcx, did)
  99         }
 100         // Assume that the enum type is reexported next to the variant, and
 101         // variants don't show up in documentation specially.
 102         def::DefVariant(..) => return Some(Vec::new()),
 103         def::DefMod(did) => {
 104             record_extern_fqn(cx, did, clean::TypeModule);
 105             clean::ModuleItem(build_module(cx, tcx, did))
 106         }
 107         def::DefStatic(did, mtbl) => {
 108             record_extern_fqn(cx, did, clean::TypeStatic);
 109             clean::StaticItem(build_static(cx, tcx, did, mtbl))
 110         }
 111         def::DefConst(did) | def::DefAssociatedConst(did) => {
 112             record_extern_fqn(cx, did, clean::TypeConst);
 113             clean::ConstantItem(build_const(cx, tcx, did))
 114         }
 115         _ => return None,
 116     };
 117     cx.inlined.borrow_mut().as_mut().unwrap().insert(did);
 118     ret.push(clean::Item {
 119         source: clean::Span::empty(),
 120         name: Some(tcx.item_name(did).to_string()),
 121         attrs: load_attrs(cx, tcx, did),
 122         inner: inner,
 123         visibility: Some(hir::Public),
 124         stability: stability::lookup(tcx, did).clean(cx),
 125         def_id: did,
 126     });
 127     Some(ret)
 128 }
 129
 130 pub fn load_attrs(cx: &DocContext, tcx: &ty::ctxt,
 131                   did: DefId) -> Vec<clean::Attribute> {
 132     let attrs = csearch::get_item_attrs(&tcx.sess.cstore, did);
 133     attrs.into_iter().map(|a| a.clean(cx)).collect()
 134 }
 135
 136 /// Record an external fully qualified name in the external_paths cache.
 137 ///
 138 /// These names are used later on by HTML rendering to generate things like
 139 /// source links back to the original item.
 140 pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
 141     match cx.tcx_opt() {
 142         Some(tcx) => {
 143             let fqn = csearch::get_item_path(tcx, did);
 144             let fqn = fqn.into_iter().map(|i| i.to_string()).collect();
 145             cx.external_paths.borrow_mut().as_mut().unwrap().insert(did, (fqn, kind));
 146         }
 147         None => {}
 148     }
 149 }
 150
 151 pub fn build_external_trait(cx: &DocContext, tcx: &ty::ctxt,
 152                             did: DefId) -> clean::Trait {
 153     let def = tcx.lookup_trait_def(did);
 154     let trait_items = tcx.trait_items(did).clean(cx);
 155     let predicates = tcx.lookup_predicates(did);
 156     let generics = (&def.generics, &predicates, subst::TypeSpace).clean(cx);
 157     let generics = filter_non_trait_generics(did, generics);
 158     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
 159     clean::Trait {
 160         unsafety: def.unsafety,
 161         generics: generics,
 162         items: trait_items,
 163         bounds: supertrait_bounds,
 164     }
 165 }
 166
 167 fn build_external_function(cx: &DocContext, tcx: &ty::ctxt, did: DefId) -> clean::Function {
 168     let t = tcx.lookup_item_type(did);
 169     let (decl, style, abi) = match t.ty.sty {
 170         ty::TyBareFn(_, ref f) => ((did, &f.sig).clean(cx), f.unsafety, f.abi),
 171         _ => panic!("bad function"),
 172     };
 173     let predicates = tcx.lookup_predicates(did);
 174     clean::Function {
 175         decl: decl,
 176         generics: (&t.generics, &predicates, subst::FnSpace).clean(cx),
 177         unsafety: style,
 178         constness: hir::Constness::NotConst,
 179         abi: abi,
 180     }
 181 }
 182
 183 fn build_struct(cx: &DocContext, tcx: &ty::ctxt, did: DefId) -> clean::Struct {
 184     use syntax::parse::token::special_idents::unnamed_field;
 185
 186     let t = tcx.lookup_item_type(did);
 187     let predicates = tcx.lookup_predicates(did);
 188     let variant = tcx.lookup_adt_def(did).struct_variant();
 189
 190     clean::Struct {
 191         struct_type: match &*variant.fields {
 192             [] => doctree::Unit,
 193             [ref f] if f.name == unnamed_field.name => doctree::Newtype,
 194             [ref f, ..] if f.name == unnamed_field.name => doctree::Tuple,
 195             _ => doctree::Plain,
 196         },
 197         generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
 198         fields: variant.fields.clean(cx),
 199         fields_stripped: false,
 200     }
 201 }
 202
 203 fn build_type(cx: &DocContext, tcx: &ty::ctxt, did: DefId) -> clean::ItemEnum {
 204     let t = tcx.lookup_item_type(did);
 205     let predicates = tcx.lookup_predicates(did);
 206     match t.ty.sty {
 207         ty::TyEnum(edef, _) if !csearch::is_typedef(&tcx.sess.cstore, did) => {
 208             return clean::EnumItem(clean::Enum {
 209                 generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
 210                 variants_stripped: false,
 211                 variants: edef.variants.clean(cx),
 212             })
 213         }
 214         _ => {}
 215     }
 216
 217     clean::TypedefItem(clean::Typedef {
 218         type_: t.ty.clean(cx),
 219         generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
 220     }, false)
 221 }
 222
 223 pub fn build_impls(cx: &DocContext, tcx: &ty::ctxt,
 224                    did: DefId) -> Vec<clean::Item> {
 225     tcx.populate_inherent_implementations_for_type_if_necessary(did);
 226     let mut impls = Vec::new();
 227
 228     match tcx.inherent_impls.borrow().get(&did) {
 229         None => {}
 230         Some(i) => {
 231             for &did in i.iter() {
 232                 build_impl(cx, tcx, did, &mut impls);
 233             }
 234         }
 235     }
 236
 237     // If this is the first time we've inlined something from this crate, then
 238     // we inline *all* impls from the crate into this crate. Note that there's
 239     // currently no way for us to filter this based on type, and we likely need
 240     // many impls for a variety of reasons.
 241     //
 242     // Primarily, the impls will be used to populate the documentation for this
 243     // type being inlined, but impls can also be used when generating
 244     // documentation for primitives (no way to find those specifically).
 245     if cx.populated_crate_impls.borrow_mut().insert(did.krate) {
 246         csearch::each_top_level_item_of_crate(&tcx.sess.cstore,
 247                                               did.krate,
 248                                               |def, _, _| {
 249             populate_impls(cx, tcx, def, &mut impls)
 250         });
 251
 252         fn populate_impls(cx: &DocContext, tcx: &ty::ctxt,
 253                           def: decoder::DefLike,
 254                           impls: &mut Vec<clean::Item>) {
 255             match def {
 256                 decoder::DlImpl(did) => build_impl(cx, tcx, did, impls),
 257                 decoder::DlDef(def::DefMod(did)) => {
 258                     csearch::each_child_of_item(&tcx.sess.cstore,
 259                                                 did,
 260                                                 |def, _, _| {
 261                         populate_impls(cx, tcx, def, impls)
 262                     })
 263                 }
 264                 _ => {}
 265             }
 266         }
 267     }
 268
 269     return impls;
 270 }
 271
 272 pub fn build_impl(cx: &DocContext,
 273                   tcx: &ty::ctxt,
 274                   did: DefId,
 275                   ret: &mut Vec<clean::Item>) {
 276     if !cx.inlined.borrow_mut().as_mut().unwrap().insert(did) {
 277         return
 278     }
 279
 280     let attrs = load_attrs(cx, tcx, did);
 281     let associated_trait = csearch::get_impl_trait(tcx, did);
 282     if let Some(ref t) = associated_trait {
 283         // If this is an impl for a #[doc(hidden)] trait, be sure to not inline
 284         let trait_attrs = load_attrs(cx, tcx, t.def_id);
 285         if trait_attrs.iter().any(|a| is_doc_hidden(a)) {
 286             return
 287         }
 288     }
 289
 290     // If this is a defaulted impl, then bail out early here
 291     if csearch::is_default_impl(&tcx.sess.cstore, did) {
 292         return ret.push(clean::Item {
 293             inner: clean::DefaultImplItem(clean::DefaultImpl {
 294                 // FIXME: this should be decoded
 295                 unsafety: hir::Unsafety::Normal,
 296                 trait_: match associated_trait.as_ref().unwrap().clean(cx) {
 297                     clean::TraitBound(polyt, _) => polyt.trait_,
 298                     clean::RegionBound(..) => unreachable!(),
 299                 },
 300             }),
 301             source: clean::Span::empty(),
 302             name: None,
 303             attrs: attrs,
 304             visibility: Some(hir::Inherited),
 305             stability: stability::lookup(tcx, did).clean(cx),
 306             def_id: did,
 307         });
 308     }
 309
 310     let predicates = tcx.lookup_predicates(did);
 311     let trait_items = csearch::get_impl_items(&tcx.sess.cstore, did)
 312             .iter()
 313             .filter_map(|did| {
 314         let did = did.def_id();
 315         let impl_item = tcx.impl_or_trait_item(did);
 316         match impl_item {
 317             ty::ConstTraitItem(ref assoc_const) => {
 318                 let did = assoc_const.def_id;
 319                 let type_scheme = tcx.lookup_item_type(did);
 320                 let default = if assoc_const.has_value {
 321                     Some(const_eval::lookup_const_by_id(tcx, did, None)
 322                          .unwrap().span.to_src(cx))
 323                 } else {
 324                     None
 325                 };
 326                 Some(clean::Item {
 327                     name: Some(assoc_const.name.clean(cx)),
 328                     inner: clean::AssociatedConstItem(
 329                         type_scheme.ty.clean(cx),
 330                         default,
 331                     ),
 332                     source: clean::Span::empty(),
 333                     attrs: vec![],
 334                     visibility: None,
 335                     stability: stability::lookup(tcx, did).clean(cx),
 336                     def_id: did
 337                 })
 338             }
 339             ty::MethodTraitItem(method) => {
 340                 if method.vis != hir::Public && associated_trait.is_none() {
 341                     return None
 342                 }
 343                 let mut item = method.clean(cx);
 344                 item.inner = match item.inner.clone() {
 345                     clean::TyMethodItem(clean::TyMethod {
 346                         unsafety, decl, self_, generics, abi
 347                     }) => {
 348                         clean::MethodItem(clean::Method {
 349                             unsafety: unsafety,
 350                             constness: hir::Constness::NotConst,
 351                             decl: decl,
 352                             self_: self_,
 353                             generics: generics,
 354                             abi: abi
 355                         })
 356                     }
 357                     _ => panic!("not a tymethod"),
 358                 };
 359                 Some(item)
 360             }
 361             ty::TypeTraitItem(ref assoc_ty) => {
 362                 let did = assoc_ty.def_id;
 363                 let type_scheme = ty::TypeScheme {
 364                     ty: assoc_ty.ty.unwrap(),
 365                     generics: ty::Generics::empty()
 366                 };
 367                 // Not sure the choice of ParamSpace actually matters here,
 368                 // because an associated type won't have generics on the LHS
 369                 let typedef = (type_scheme, ty::GenericPredicates::empty(),
 370                                subst::ParamSpace::TypeSpace).clean(cx);
 371                 Some(clean::Item {
 372                     name: Some(assoc_ty.name.clean(cx)),
 373                     inner: clean::TypedefItem(typedef, true),
 374                     source: clean::Span::empty(),
 375                     attrs: vec![],
 376                     visibility: None,
 377                     stability: stability::lookup(tcx, did).clean(cx),
 378                     def_id: did
 379                 })
 380             }
 381         }
 382     }).collect::<Vec<_>>();
 383     let polarity = csearch::get_impl_polarity(tcx, did);
 384     let ty = tcx.lookup_item_type(did);
 385     let trait_ = associated_trait.clean(cx).map(|bound| {
 386         match bound {
 387             clean::TraitBound(polyt, _) => polyt.trait_,
 388             clean::RegionBound(..) => unreachable!(),
 389         }
 390     });
 391     if let Some(clean::ResolvedPath { did, .. }) = trait_ {
 392         if Some(did) == cx.deref_trait_did.get() {
 393             super::build_deref_target_impls(cx, &trait_items, ret);
 394         }
 395     }
 396     ret.push(clean::Item {
 397         inner: clean::ImplItem(clean::Impl {
 398             unsafety: hir::Unsafety::Normal, // FIXME: this should be decoded
 399             derived: clean::detect_derived(&attrs),
 400             trait_: trait_,
 401             for_: ty.ty.clean(cx),
 402             generics: (&ty.generics, &predicates, subst::TypeSpace).clean(cx),
 403             items: trait_items,
 404             polarity: polarity.map(|p| { p.clean(cx) }),
 405         }),
 406         source: clean::Span::empty(),
 407         name: None,
 408         attrs: attrs,
 409         visibility: Some(hir::Inherited),
 410         stability: stability::lookup(tcx, did).clean(cx),
 411         def_id: did,
 412     });
 413
 414     fn is_doc_hidden(a: &clean::Attribute) -> bool {
 415         match *a {
 416             clean::List(ref name, ref inner) if *name == "doc" => {
 417                 inner.iter().any(|a| {
 418                     match *a {
 419                         clean::Word(ref s) => *s == "hidden",
 420                         _ => false,
 421                     }
 422                 })
 423             }
 424             _ => false
 425         }
 426     }
 427 }
 428
 429 fn build_module(cx: &DocContext, tcx: &ty::ctxt,
 430                 did: DefId) -> clean::Module {
 431     let mut items = Vec::new();
 432     fill_in(cx, tcx, did, &mut items);
 433     return clean::Module {
 434         items: items,
 435         is_crate: false,
 436     };
 437
 438     fn fill_in(cx: &DocContext, tcx: &ty::ctxt, did: DefId,
 439                items: &mut Vec<clean::Item>) {
 440         // If we're reexporting a reexport it may actually reexport something in
 441         // two namespaces, so the target may be listed twice. Make sure we only
 442         // visit each node at most once.
 443         let mut visited = HashSet::new();
 444         csearch::each_child_of_item(&tcx.sess.cstore, did, |def, _, vis| {
 445             match def {
 446                 decoder::DlDef(def::DefForeignMod(did)) => {
 447                     fill_in(cx, tcx, did, items);
 448                 }
 449                 decoder::DlDef(def) if vis == hir::Public => {
 450                     if !visited.insert(def) { return }
 451                     match try_inline_def(cx, tcx, def) {
 452                         Some(i) => items.extend(i),
 453                         None => {}
 454                     }
 455                 }
 456                 decoder::DlDef(..) => {}
 457                 // All impls were inlined above
 458                 decoder::DlImpl(..) => {}
 459                 decoder::DlField => panic!("unimplemented field"),
 460             }
 461         });
 462     }
 463 }
 464
 465 fn build_const(cx: &DocContext, tcx: &ty::ctxt,
 466                did: DefId) -> clean::Constant {
 467     use rustc::middle::const_eval;
 468     use rustc_front::print::pprust;
 469
 470     let expr = const_eval::lookup_const_by_id(tcx, did, None).unwrap_or_else(|| {
 471         panic!("expected lookup_const_by_id to succeed for {:?}", did);
 472     });
 473     debug!("converting constant expr {:?} to snippet", expr);
 474     let sn = pprust::expr_to_string(expr);
 475     debug!("got snippet {}", sn);
 476
 477     clean::Constant {
 478         type_: tcx.lookup_item_type(did).ty.clean(cx),
 479         expr: sn
 480     }
 481 }
 482
 483 fn build_static(cx: &DocContext, tcx: &ty::ctxt,
 484                 did: DefId,
 485                 mutable: bool) -> clean::Static {
 486     clean::Static {
 487         type_: tcx.lookup_item_type(did).ty.clean(cx),
 488         mutability: if mutable {clean::Mutable} else {clean::Immutable},
 489         expr: "\n\n\n".to_string(), // trigger the "[definition]" links
 490     }
 491 }
 492
 493 /// A trait's generics clause actually contains all of the predicates for all of
 494 /// its associated types as well. We specifically move these clauses to the
 495 /// associated types instead when displaying, so when we're genering the
 496 /// generics for the trait itself we need to be sure to remove them.
 497 ///
 498 /// The inverse of this filtering logic can be found in the `Clean`
 499 /// implementation for `AssociatedType`
 500 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics)
 501                              -> clean::Generics {
 502     g.where_predicates.retain(|pred| {
 503         match *pred {
 504             clean::WherePredicate::BoundPredicate {
 505                 ty: clean::QPath {
 506                     self_type: box clean::Generic(ref s),
 507                     trait_: box clean::ResolvedPath { did, .. },
 508                     name: ref _name,
 509                 }, ..
 510             } => *s != "Self" || did != trait_did,
 511             _ => true,
 512         }
 513     });
 514     return g;
 515 }
 516
 517 /// Supertrait bounds for a trait are also listed in the generics coming from
 518 /// the metadata for a crate, so we want to separate those out and create a new
 519 /// list of explicit supertrait bounds to render nicely.
 520 fn separate_supertrait_bounds(mut g: clean::Generics)
 521                               -> (clean::Generics, Vec<clean::TyParamBound>) {
 522     let mut ty_bounds = Vec::new();
 523     g.where_predicates.retain(|pred| {
 524         match *pred {
 525             clean::WherePredicate::BoundPredicate {
 526                 ty: clean::Generic(ref s),
 527                 ref bounds
 528             } if *s == "Self" => {
 529                 ty_bounds.extend(bounds.iter().cloned());
 530                 false
 531             }
 532             _ => true,
 533         }
 534     });
 535     (g, ty_bounds)
 536 }