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::middle::cstore::{self, CrateStore};
  20 use rustc::middle::def;
  21 use rustc::middle::def_id::DefId;
  22 use rustc::middle::ty;
  23 use rustc::middle::subst;
  24 use rustc::middle::stability;
  25 use rustc::middle::const_eval;
  26
  27 use core::DocContext;
  28 use doctree;
  29 use clean;
  30
  31 use super::{Clean, ToSource};
  32
  33 /// Attempt to inline the definition of a local node id into this AST.
  34 ///
  35 /// This function will fetch the definition of the id specified, and if it is
  36 /// from another crate it will attempt to inline the documentation from the
  37 /// other crate into this crate.
  38 ///
  39 /// This is primarily used for `pub use` statements which are, in general,
  40 /// implementation details. Inlining the documentation should help provide a
  41 /// better experience when reading the documentation in this use case.
  42 ///
  43 /// The returned value is `None` if the `id` could not be inlined, and `Some`
  44 /// of a vector of items if it was successfully expanded.
  45 pub fn try_inline(cx: &DocContext, id: ast::NodeId, into: Option<ast::Name>)
  46                   -> Option<Vec<clean::Item>> {
  47     let tcx = match cx.tcx_opt() {
  48         Some(tcx) => tcx,
  49         None => return None,
  50     };
  51     let def = match tcx.def_map.borrow().get(&id) {
  52         Some(d) => d.full_def(),
  53         None => return None,
  54     };
  55     let did = def.def_id();
  56     if did.is_local() { return None }
  57     try_inline_def(cx, tcx, def).map(|vec| {
  58         vec.into_iter().map(|mut item| {
  59             match into {
  60                 Some(into) if item.name.is_some() => {
  61                     item.name = Some(into.clean(cx));
  62                 }
  63                 _ => {}
  64             }
  65             item
  66         }).collect()
  67     })
  68 }
  69
  70 fn try_inline_def(cx: &DocContext, tcx: &ty::ctxt,
  71                   def: def::Def) -> Option<Vec<clean::Item>> {
  72     let mut ret = Vec::new();
  73     let did = def.def_id();
  74     let inner = match def {
  75         def::DefTrait(did) => {
  76             record_extern_fqn(cx, did, clean::TypeTrait);
  77             clean::TraitItem(build_external_trait(cx, tcx, did))
  78         }
  79         def::DefFn(did, false) => {
  80             // If this function is a tuple struct constructor, we just skip it
  81             record_extern_fqn(cx, did, clean::TypeFunction);
  82             clean::FunctionItem(build_external_function(cx, tcx, did))
  83         }
  84         def::DefStruct(did) => {
  85             record_extern_fqn(cx, did, clean::TypeStruct);
  86             ret.extend(build_impls(cx, tcx, did));
  87             clean::StructItem(build_struct(cx, tcx, did))
  88         }
  89         def::DefTy(did, false) => {
  90             record_extern_fqn(cx, did, clean::TypeTypedef);
  91             ret.extend(build_impls(cx, tcx, did));
  92             build_type(cx, tcx, did)
  93         }
  94         def::DefTy(did, true) => {
  95             record_extern_fqn(cx, did, clean::TypeEnum);
  96             ret.extend(build_impls(cx, tcx, did));
  97             build_type(cx, tcx, did)
  98         }
  99         // Assume that the enum type is reexported next to the variant, and
 100         // variants don't show up in documentation specially.
 101         def::DefVariant(..) => return Some(Vec::new()),
 102         def::DefMod(did) => {
 103             record_extern_fqn(cx, did, clean::TypeModule);
 104             clean::ModuleItem(build_module(cx, tcx, did))
 105         }
 106         def::DefStatic(did, mtbl) => {
 107             record_extern_fqn(cx, did, clean::TypeStatic);
 108             clean::StaticItem(build_static(cx, tcx, did, mtbl))
 109         }
 110         def::DefConst(did) | def::DefAssociatedConst(did) => {
 111             record_extern_fqn(cx, did, clean::TypeConst);
 112             clean::ConstantItem(build_const(cx, tcx, did))
 113         }
 114         _ => return None,
 115     };
 116     cx.inlined.borrow_mut().as_mut().unwrap().insert(did);
 117     ret.push(clean::Item {
 118         source: clean::Span::empty(),
 119         name: Some(tcx.item_name(did).to_string()),
 120         attrs: load_attrs(cx, tcx, did),
 121         inner: inner,
 122         visibility: Some(hir::Public),
 123         stability: stability::lookup_stability(tcx, did).clean(cx),
 124         deprecation: stability::lookup_deprecation(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     tcx.get_attrs(did).iter().map(|a| a.clean(cx)).collect()
 133 }
 134
 135 /// Record an external fully qualified name in the external_paths cache.
 136 ///
 137 /// These names are used later on by HTML rendering to generate things like
 138 /// source links back to the original item.
 139 pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
 140     match cx.tcx_opt() {
 141         Some(tcx) => {
 142             let fqn = tcx.sess.cstore.extern_item_path(did);
 143             let fqn = fqn.into_iter().map(|i| i.to_string()).collect();
 144             cx.external_paths.borrow_mut().as_mut().unwrap().insert(did, (fqn, kind));
 145         }
 146         None => {}
 147     }
 148 }
 149
 150 pub fn build_external_trait(cx: &DocContext, tcx: &ty::ctxt,
 151                             did: DefId) -> clean::Trait {
 152     let def = tcx.lookup_trait_def(did);
 153     let trait_items = tcx.trait_items(did).clean(cx);
 154     let predicates = tcx.lookup_predicates(did);
 155     let generics = (&def.generics, &predicates, subst::TypeSpace).clean(cx);
 156     let generics = filter_non_trait_generics(did, generics);
 157     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
 158     clean::Trait {
 159         unsafety: def.unsafety,
 160         generics: generics,
 161         items: trait_items,
 162         bounds: supertrait_bounds,
 163     }
 164 }
 165
 166 fn build_external_function(cx: &DocContext, tcx: &ty::ctxt, did: DefId) -> clean::Function {
 167     let t = tcx.lookup_item_type(did);
 168     let (decl, style, abi) = match t.ty.sty {
 169         ty::TyBareFn(_, ref f) => ((did, &f.sig).clean(cx), f.unsafety, f.abi),
 170         _ => panic!("bad function"),
 171     };
 172
 173     let constness = if tcx.sess.cstore.is_const_fn(did) {
 174         hir::Constness::Const
 175     } else {
 176         hir::Constness::NotConst
 177     };
 178
 179     let predicates = tcx.lookup_predicates(did);
 180     clean::Function {
 181         decl: decl,
 182         generics: (&t.generics, &predicates, subst::FnSpace).clean(cx),
 183         unsafety: style,
 184         constness: constness,
 185         abi: abi,
 186     }
 187 }
 188
 189 fn build_struct(cx: &DocContext, tcx: &ty::ctxt, did: DefId) -> clean::Struct {
 190     use syntax::parse::token::special_idents::unnamed_field;
 191
 192     let t = tcx.lookup_item_type(did);
 193     let predicates = tcx.lookup_predicates(did);
 194     let variant = tcx.lookup_adt_def(did).struct_variant();
 195
 196     clean::Struct {
 197         struct_type: match &*variant.fields {
 198             [] => doctree::Unit,
 199             [ref f] if f.name == unnamed_field.name => doctree::Newtype,
 200             [ref f, ..] if f.name == unnamed_field.name => doctree::Tuple,
 201             _ => doctree::Plain,
 202         },
 203         generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
 204         fields: variant.fields.clean(cx),
 205         fields_stripped: false,
 206     }
 207 }
 208
 209 fn build_type(cx: &DocContext, tcx: &ty::ctxt, did: DefId) -> clean::ItemEnum {
 210     let t = tcx.lookup_item_type(did);
 211     let predicates = tcx.lookup_predicates(did);
 212     match t.ty.sty {
 213         ty::TyEnum(edef, _) if !tcx.sess.cstore.is_typedef(did) => {
 214             return clean::EnumItem(clean::Enum {
 215                 generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
 216                 variants_stripped: false,
 217                 variants: edef.variants.clean(cx),
 218             })
 219         }
 220         _ => {}
 221     }
 222
 223     clean::TypedefItem(clean::Typedef {
 224         type_: t.ty.clean(cx),
 225         generics: (&t.generics, &predicates, subst::TypeSpace).clean(cx),
 226     }, false)
 227 }
 228
 229 pub fn build_impls(cx: &DocContext, tcx: &ty::ctxt,
 230                    did: DefId) -> Vec<clean::Item> {
 231     tcx.populate_inherent_implementations_for_type_if_necessary(did);
 232     let mut impls = Vec::new();
 233
 234     match tcx.inherent_impls.borrow().get(&did) {
 235         None => {}
 236         Some(i) => {
 237             for &did in i.iter() {
 238                 build_impl(cx, tcx, did, &mut impls);
 239             }
 240         }
 241     }
 242
 243     // If this is the first time we've inlined something from this crate, then
 244     // we inline *all* impls from the crate into this crate. Note that there's
 245     // currently no way for us to filter this based on type, and we likely need
 246     // many impls for a variety of reasons.
 247     //
 248     // Primarily, the impls will be used to populate the documentation for this
 249     // type being inlined, but impls can also be used when generating
 250     // documentation for primitives (no way to find those specifically).
 251     if cx.populated_crate_impls.borrow_mut().insert(did.krate) {
 252         for item in tcx.sess.cstore.crate_top_level_items(did.krate) {
 253             populate_impls(cx, tcx, item.def, &mut impls);
 254         }
 255
 256         fn populate_impls(cx: &DocContext, tcx: &ty::ctxt,
 257                           def: cstore::DefLike,
 258                           impls: &mut Vec<clean::Item>) {
 259             match def {
 260                 cstore::DlImpl(did) => build_impl(cx, tcx, did, impls),
 261                 cstore::DlDef(def::DefMod(did)) => {
 262                     for item in tcx.sess.cstore.item_children(did) {
 263                         populate_impls(cx, tcx, item.def, impls)
 264                     }
 265                 }
 266                 _ => {}
 267             }
 268         }
 269     }
 270
 271     return impls;
 272 }
 273
 274 pub fn build_impl(cx: &DocContext,
 275                   tcx: &ty::ctxt,
 276                   did: DefId,
 277                   ret: &mut Vec<clean::Item>) {
 278     if !cx.inlined.borrow_mut().as_mut().unwrap().insert(did) {
 279         return
 280     }
 281
 282     let attrs = load_attrs(cx, tcx, did);
 283     let associated_trait = tcx.impl_trait_ref(did);
 284     if let Some(ref t) = associated_trait {
 285         // If this is an impl for a #[doc(hidden)] trait, be sure to not inline
 286         let trait_attrs = load_attrs(cx, tcx, t.def_id);
 287         if trait_attrs.iter().any(|a| is_doc_hidden(a)) {
 288             return
 289         }
 290     }
 291
 292     // If this is a defaulted impl, then bail out early here
 293     if tcx.sess.cstore.is_default_impl(did) {
 294         return ret.push(clean::Item {
 295             inner: clean::DefaultImplItem(clean::DefaultImpl {
 296                 // FIXME: this should be decoded
 297                 unsafety: hir::Unsafety::Normal,
 298                 trait_: match associated_trait.as_ref().unwrap().clean(cx) {
 299                     clean::TraitBound(polyt, _) => polyt.trait_,
 300                     clean::RegionBound(..) => unreachable!(),
 301                 },
 302             }),
 303             source: clean::Span::empty(),
 304             name: None,
 305             attrs: attrs,
 306             visibility: Some(hir::Inherited),
 307             stability: stability::lookup_stability(tcx, did).clean(cx),
 308             deprecation: stability::lookup_deprecation(tcx, did).clean(cx),
 309             def_id: did,
 310         });
 311     }
 312
 313     let predicates = tcx.lookup_predicates(did);
 314     let trait_items = tcx.sess.cstore.impl_items(did)
 315             .iter()
 316             .filter_map(|did| {
 317         let did = did.def_id();
 318         let impl_item = tcx.impl_or_trait_item(did);
 319         match impl_item {
 320             ty::ConstTraitItem(ref assoc_const) => {
 321                 let did = assoc_const.def_id;
 322                 let type_scheme = tcx.lookup_item_type(did);
 323                 let default = if assoc_const.has_value {
 324                     Some(const_eval::lookup_const_by_id(tcx, did, None, None)
 325                          .unwrap().span.to_src(cx))
 326                 } else {
 327                     None
 328                 };
 329                 Some(clean::Item {
 330                     name: Some(assoc_const.name.clean(cx)),
 331                     inner: clean::AssociatedConstItem(
 332                         type_scheme.ty.clean(cx),
 333                         default,
 334                     ),
 335                     source: clean::Span::empty(),
 336                     attrs: vec![],
 337                     visibility: None,
 338                     stability: stability::lookup_stability(tcx, did).clean(cx),
 339                     deprecation: stability::lookup_deprecation(tcx, did).clean(cx),
 340                     def_id: did
 341                 })
 342             }
 343             ty::MethodTraitItem(method) => {
 344                 if method.vis != hir::Public && associated_trait.is_none() {
 345                     return None
 346                 }
 347                 let mut item = method.clean(cx);
 348                 item.inner = match item.inner.clone() {
 349                     clean::TyMethodItem(clean::TyMethod {
 350                         unsafety, decl, self_, generics, abi
 351                     }) => {
 352                         let constness = if tcx.sess.cstore.is_const_fn(did) {
 353                             hir::Constness::Const
 354                         } else {
 355                             hir::Constness::NotConst
 356                         };
 357
 358                         clean::MethodItem(clean::Method {
 359                             unsafety: unsafety,
 360                             constness: constness,
 361                             decl: decl,
 362                             self_: self_,
 363                             generics: generics,
 364                             abi: abi
 365                         })
 366                     }
 367                     _ => panic!("not a tymethod"),
 368                 };
 369                 Some(item)
 370             }
 371             ty::TypeTraitItem(ref assoc_ty) => {
 372                 let did = assoc_ty.def_id;
 373                 let type_scheme = ty::TypeScheme {
 374                     ty: assoc_ty.ty.unwrap(),
 375                     generics: ty::Generics::empty()
 376                 };
 377                 // Not sure the choice of ParamSpace actually matters here,
 378                 // because an associated type won't have generics on the LHS
 379                 let typedef = (type_scheme, ty::GenericPredicates::empty(),
 380                                subst::ParamSpace::TypeSpace).clean(cx);
 381                 Some(clean::Item {
 382                     name: Some(assoc_ty.name.clean(cx)),
 383                     inner: clean::TypedefItem(typedef, true),
 384                     source: clean::Span::empty(),
 385                     attrs: vec![],
 386                     visibility: None,
 387                     stability: stability::lookup_stability(tcx, did).clean(cx),
 388                     deprecation: stability::lookup_deprecation(tcx, did).clean(cx),
 389                     def_id: did
 390                 })
 391             }
 392         }
 393     }).collect::<Vec<_>>();
 394     let polarity = tcx.trait_impl_polarity(did);
 395     let ty = tcx.lookup_item_type(did);
 396     let trait_ = associated_trait.clean(cx).map(|bound| {
 397         match bound {
 398             clean::TraitBound(polyt, _) => polyt.trait_,
 399             clean::RegionBound(..) => unreachable!(),
 400         }
 401     });
 402     if let Some(clean::ResolvedPath { did, .. }) = trait_ {
 403         if Some(did) == cx.deref_trait_did.get() {
 404             super::build_deref_target_impls(cx, &trait_items, ret);
 405         }
 406     }
 407     ret.push(clean::Item {
 408         inner: clean::ImplItem(clean::Impl {
 409             unsafety: hir::Unsafety::Normal, // FIXME: this should be decoded
 410             derived: clean::detect_derived(&attrs),
 411             trait_: trait_,
 412             for_: ty.ty.clean(cx),
 413             generics: (&ty.generics, &predicates, subst::TypeSpace).clean(cx),
 414             items: trait_items,
 415             polarity: polarity.map(|p| { p.clean(cx) }),
 416         }),
 417         source: clean::Span::empty(),
 418         name: None,
 419         attrs: attrs,
 420         visibility: Some(hir::Inherited),
 421         stability: stability::lookup_stability(tcx, did).clean(cx),
 422         deprecation: stability::lookup_deprecation(tcx, did).clean(cx),
 423         def_id: did,
 424     });
 425
 426     fn is_doc_hidden(a: &clean::Attribute) -> bool {
 427         match *a {
 428             clean::List(ref name, ref inner) if *name == "doc" => {
 429                 inner.iter().any(|a| {
 430                     match *a {
 431                         clean::Word(ref s) => *s == "hidden",
 432                         _ => false,
 433                     }
 434                 })
 435             }
 436             _ => false
 437         }
 438     }
 439 }
 440
 441 fn build_module(cx: &DocContext, tcx: &ty::ctxt,
 442                 did: DefId) -> clean::Module {
 443     let mut items = Vec::new();
 444     fill_in(cx, tcx, did, &mut items);
 445     return clean::Module {
 446         items: items,
 447         is_crate: false,
 448     };
 449
 450     fn fill_in(cx: &DocContext, tcx: &ty::ctxt, did: DefId,
 451                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 = HashSet::new();
 456         for item in tcx.sess.cstore.item_children(did) {
 457             match item.def {
 458                 cstore::DlDef(def::DefForeignMod(did)) => {
 459                     fill_in(cx, tcx, did, items);
 460                 }
 461                 cstore::DlDef(def) if item.vis == hir::Public => {
 462                     if !visited.insert(def) { continue }
 463                     match try_inline_def(cx, tcx, def) {
 464                         Some(i) => items.extend(i),
 465                         None => {}
 466                     }
 467                 }
 468                 cstore::DlDef(..) => {}
 469                 // All impls were inlined above
 470                 cstore::DlImpl(..) => {}
 471                 cstore::DlField => panic!("unimplemented field"),
 472             }
 473         }
 474     }
 475 }
 476
 477 fn build_const(cx: &DocContext, tcx: &ty::ctxt,
 478                did: DefId) -> clean::Constant {
 479     use rustc::middle::const_eval;
 480     use rustc_front::print::pprust;
 481
 482     let expr = const_eval::lookup_const_by_id(tcx, did, None, None).unwrap_or_else(|| {
 483         panic!("expected lookup_const_by_id to succeed for {:?}", did);
 484     });
 485     debug!("converting constant expr {:?} to snippet", expr);
 486     let sn = pprust::expr_to_string(expr);
 487     debug!("got snippet {}", sn);
 488
 489     clean::Constant {
 490         type_: tcx.lookup_item_type(did).ty.clean(cx),
 491         expr: sn
 492     }
 493 }
 494
 495 fn build_static(cx: &DocContext, tcx: &ty::ctxt,
 496                 did: DefId,
 497                 mutable: bool) -> clean::Static {
 498     clean::Static {
 499         type_: tcx.lookup_item_type(did).ty.clean(cx),
 500         mutability: if mutable {clean::Mutable} else {clean::Immutable},
 501         expr: "\n\n\n".to_string(), // trigger the "[definition]" links
 502     }
 503 }
 504
 505 /// A trait's generics clause actually contains all of the predicates for all of
 506 /// its associated types as well. We specifically move these clauses to the
 507 /// associated types instead when displaying, so when we're genering the
 508 /// generics for the trait itself we need to be sure to remove them.
 509 ///
 510 /// The inverse of this filtering logic can be found in the `Clean`
 511 /// implementation for `AssociatedType`
 512 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics)
 513                              -> clean::Generics {
 514     g.where_predicates.retain(|pred| {
 515         match *pred {
 516             clean::WherePredicate::BoundPredicate {
 517                 ty: clean::QPath {
 518                     self_type: box clean::Generic(ref s),
 519                     trait_: box clean::ResolvedPath { did, .. },
 520                     name: ref _name,
 521                 }, ..
 522             } => *s != "Self" || did != trait_did,
 523             _ => true,
 524         }
 525     });
 526     return g;
 527 }
 528
 529 /// Supertrait bounds for a trait are also listed in the generics coming from
 530 /// the metadata for a crate, so we want to separate those out and create a new
 531 /// list of explicit supertrait bounds to render nicely.
 532 fn separate_supertrait_bounds(mut g: clean::Generics)
 533                               -> (clean::Generics, Vec<clean::TyParamBound>) {
 534     let mut ty_bounds = Vec::new();
 535     g.where_predicates.retain(|pred| {
 536         match *pred {
 537             clean::WherePredicate::BoundPredicate {
 538                 ty: clean::Generic(ref s),
 539                 ref bounds
 540             } if *s == "Self" => {
 541                 ty_bounds.extend(bounds.iter().cloned());
 542                 false
 543             }
 544             _ => true,
 545         }
 546     });
 547     (g, ty_bounds)
 548 }