src/librustdoc/passes/collect_intra_doc_links.rs

   1 // Copyright 2018 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 use clean::*;
  12
  13 use rustc::lint as lint;
  14 use rustc::hir;
  15 use rustc::hir::def::Def;
  16 use rustc::ty;
  17 use syntax;
  18 use syntax::ast::{self, Ident, NodeId};
  19 use syntax::feature_gate::UnstableFeatures;
  20 use syntax::symbol::Symbol;
  21 use syntax_pos::{self, DUMMY_SP};
  22
  23 use std::ops::Range;
  24
  25 use core::DocContext;
  26 use fold::DocFolder;
  27 use html::markdown::markdown_links;
  28 use passes::Pass;
  29
  30 pub const COLLECT_INTRA_DOC_LINKS: Pass =
  31     Pass::early("collect-intra-doc-links", collect_intra_doc_links,
  32                 "reads a crate's documentation to resolve intra-doc-links");
  33
  34 pub fn collect_intra_doc_links(krate: Crate, cx: &DocContext) -> Crate {
  35     if !UnstableFeatures::from_environment().is_nightly_build() {
  36         krate
  37     } else {
  38         let mut coll = LinkCollector::new(cx);
  39
  40         coll.fold_crate(krate)
  41     }
  42 }
  43
  44 #[derive(Debug)]
  45 enum PathKind {
  46     /// can be either value or type, not a macro
  47     Unknown,
  48     /// macro
  49     Macro,
  50     /// values, functions, consts, statics, everything in the value namespace
  51     Value,
  52     /// types, traits, everything in the type namespace
  53     Type,
  54 }
  55
  56 struct LinkCollector<'a, 'tcx: 'a, 'rcx: 'a, 'cstore: 'rcx> {
  57     cx: &'a DocContext<'a, 'tcx, 'rcx, 'cstore>,
  58     mod_ids: Vec<NodeId>,
  59 }
  60
  61 impl<'a, 'tcx, 'rcx, 'cstore> LinkCollector<'a, 'tcx, 'rcx, 'cstore> {
  62     fn new(cx: &'a DocContext<'a, 'tcx, 'rcx, 'cstore>) -> Self {
  63         LinkCollector {
  64             cx,
  65             mod_ids: Vec::new(),
  66         }
  67     }
  68
  69     /// Resolve a given string as a path, along with whether or not it is
  70     /// in the value namespace. Also returns an optional URL fragment in the case
  71     /// of variants and methods
  72     fn resolve(&self, path_str: &str, is_val: bool, current_item: &Option<String>)
  73         -> Result<(Def, Option<String>), ()>
  74     {
  75         let cx = self.cx;
  76
  77         // In case we're in a module, try to resolve the relative
  78         // path
  79         if let Some(id) = self.mod_ids.last() {
  80             let result = cx.resolver.borrow_mut()
  81                                     .with_scope(*id,
  82                 |resolver| {
  83                     resolver.resolve_str_path_error(DUMMY_SP,
  84                                                     &path_str, is_val)
  85             });
  86
  87             if let Ok(result) = result {
  88                 // In case this is a trait item, skip the
  89                 // early return and try looking for the trait
  90                 let value = match result.def {
  91                     Def::Method(_) | Def::AssociatedConst(_) => true,
  92                     Def::AssociatedTy(_) => false,
  93                     Def::Variant(_) => return handle_variant(cx, result.def),
  94                     // not a trait item, just return what we found
  95                     _ => return Ok((result.def, None))
  96                 };
  97
  98                 if value != is_val {
  99                     return Err(())
 100                 }
 101             } else if let Some(prim) = is_primitive(path_str, is_val) {
 102                 return Ok((prim, Some(path_str.to_owned())))
 103             } else {
 104                 // If resolution failed, it may still be a method
 105                 // because methods are not handled by the resolver
 106                 // If so, bail when we're not looking for a value
 107                 if !is_val {
 108                     return Err(())
 109                 }
 110             }
 111
 112             // Try looking for methods and associated items
 113             let mut split = path_str.rsplitn(2, "::");
 114             let item_name = if let Some(first) = split.next() {
 115                 first
 116             } else {
 117                 return Err(())
 118             };
 119
 120             let mut path = if let Some(second) = split.next() {
 121                 second.to_owned()
 122             } else {
 123                 return Err(())
 124             };
 125
 126             if path == "self" || path == "Self" {
 127                 if let Some(name) = current_item.as_ref() {
 128                     path = name.clone();
 129                 }
 130             }
 131
 132             let ty = cx.resolver.borrow_mut()
 133                                 .with_scope(*id,
 134                 |resolver| {
 135                     resolver.resolve_str_path_error(DUMMY_SP, &path, false)
 136             })?;
 137             match ty.def {
 138                 Def::Struct(did) | Def::Union(did) | Def::Enum(did) | Def::TyAlias(did) => {
 139                     let item = cx.tcx.inherent_impls(did)
 140                                      .iter()
 141                                      .flat_map(|imp| cx.tcx.associated_items(*imp))
 142                                      .find(|item| item.ident.name == item_name);
 143                     if let Some(item) = item {
 144                         let out = match item.kind {
 145                             ty::AssociatedKind::Method if is_val => "method",
 146                             ty::AssociatedKind::Const if is_val => "associatedconstant",
 147                             _ => return Err(())
 148                         };
 149                         Ok((ty.def, Some(format!("{}.{}", out, item_name))))
 150                     } else {
 151                         match cx.tcx.type_of(did).sty {
 152                             ty::Adt(def, _) => {
 153                                 if let Some(item) = if def.is_enum() {
 154                                     def.all_fields().find(|item| item.ident.name == item_name)
 155                                 } else {
 156                                     def.non_enum_variant()
 157                                        .fields
 158                                        .iter()
 159                                        .find(|item| item.ident.name == item_name)
 160                                 } {
 161                                     Ok((ty.def,
 162                                         Some(format!("{}.{}",
 163                                                      if def.is_enum() {
 164                                                          "variant"
 165                                                      } else {
 166                                                          "structfield"
 167                                                      },
 168                                                      item.ident))))
 169                                 } else {
 170                                     Err(())
 171                                 }
 172                             }
 173                             _ => Err(()),
 174                         }
 175                     }
 176                 }
 177                 Def::Trait(did) => {
 178                     let item = cx.tcx.associated_item_def_ids(did).iter()
 179                                  .map(|item| cx.tcx.associated_item(*item))
 180                                  .find(|item| item.ident.name == item_name);
 181                     if let Some(item) = item {
 182                         let kind = match item.kind {
 183                             ty::AssociatedKind::Const if is_val => "associatedconstant",
 184                             ty::AssociatedKind::Type if !is_val => "associatedtype",
 185                             ty::AssociatedKind::Method if is_val => {
 186                                 if item.defaultness.has_value() {
 187                                     "method"
 188                                 } else {
 189                                     "tymethod"
 190                                 }
 191                             }
 192                             _ => return Err(())
 193                         };
 194
 195                         Ok((ty.def, Some(format!("{}.{}", kind, item_name))))
 196                     } else {
 197                         Err(())
 198                     }
 199                 }
 200                 _ => Err(())
 201             }
 202         } else {
 203             Err(())
 204         }
 205     }
 206 }
 207
 208 impl<'a, 'tcx, 'rcx, 'cstore> DocFolder for LinkCollector<'a, 'tcx, 'rcx, 'cstore> {
 209     fn fold_item(&mut self, mut item: Item) -> Option<Item> {
 210         let item_node_id = if item.is_mod() {
 211             if let Some(id) = self.cx.tcx.hir.as_local_node_id(item.def_id) {
 212                 Some(id)
 213             } else {
 214                 debug!("attempting to fold on a non-local item: {:?}", item);
 215                 return self.fold_item_recur(item);
 216             }
 217         } else {
 218             None
 219         };
 220
 221         let current_item = match item.inner {
 222             ModuleItem(..) => {
 223                 if item.attrs.inner_docs {
 224                     if item_node_id.unwrap() != NodeId::new(0) {
 225                         item.name.clone()
 226                     } else {
 227                         None
 228                     }
 229                 } else {
 230                     match self.mod_ids.last() {
 231                         Some(parent) if *parent != NodeId::new(0) => {
 232                             //FIXME: can we pull the parent module's name from elsewhere?
 233                             Some(self.cx.tcx.hir.name(*parent).to_string())
 234                         }
 235                         _ => None,
 236                     }
 237                 }
 238             }
 239             ImplItem(Impl { ref for_, .. }) => {
 240                 for_.def_id().map(|did| self.cx.tcx.item_name(did).to_string())
 241             }
 242             // we don't display docs on `extern crate` items anyway, so don't process them
 243             ExternCrateItem(..) => return self.fold_item_recur(item),
 244             ImportItem(Import::Simple(ref name, ..)) => Some(name.clone()),
 245             MacroItem(..) => None,
 246             _ => item.name.clone(),
 247         };
 248
 249         if item.is_mod() && item.attrs.inner_docs {
 250             self.mod_ids.push(item_node_id.unwrap());
 251         }
 252
 253         let cx = self.cx;
 254         let dox = item.attrs.collapsed_doc_value().unwrap_or_else(String::new);
 255
 256         for (ori_link, link_range) in markdown_links(&dox) {
 257             // bail early for real links
 258             if ori_link.contains('/') {
 259                 continue;
 260             }
 261             let link = ori_link.replace("`", "");
 262             let (def, fragment) = {
 263                 let mut kind = PathKind::Unknown;
 264                 let path_str = if let Some(prefix) =
 265                     ["struct@", "enum@", "type@",
 266                      "trait@", "union@"].iter()
 267                                       .find(|p| link.starts_with(**p)) {
 268                     kind = PathKind::Type;
 269                     link.trim_left_matches(prefix)
 270                 } else if let Some(prefix) =
 271                     ["const@", "static@",
 272                      "value@", "function@", "mod@",
 273                      "fn@", "module@", "method@"]
 274                         .iter().find(|p| link.starts_with(**p)) {
 275                     kind = PathKind::Value;
 276                     link.trim_left_matches(prefix)
 277                 } else if link.ends_with("()") {
 278                     kind = PathKind::Value;
 279                     link.trim_right_matches("()")
 280                 } else if link.starts_with("macro@") {
 281                     kind = PathKind::Macro;
 282                     link.trim_left_matches("macro@")
 283                 } else if link.ends_with('!') {
 284                     kind = PathKind::Macro;
 285                     link.trim_right_matches('!')
 286                 } else {
 287                     &link[..]
 288                 }.trim();
 289
 290                 if path_str.contains(|ch: char| !(ch.is_alphanumeric() ||
 291                                                   ch == ':' || ch == '_')) {
 292                     continue;
 293                 }
 294
 295                 match kind {
 296                     PathKind::Value => {
 297                         if let Ok(def) = self.resolve(path_str, true, &current_item) {
 298                             def
 299                         } else {
 300                             resolution_failure(cx, &item.attrs, path_str, &dox, link_range);
 301                             // this could just be a normal link or a broken link
 302                             // we could potentially check if something is
 303                             // "intra-doc-link-like" and warn in that case
 304                             continue;
 305                         }
 306                     }
 307                     PathKind::Type => {
 308                         if let Ok(def) = self.resolve(path_str, false, &current_item) {
 309                             def
 310                         } else {
 311                             resolution_failure(cx, &item.attrs, path_str, &dox, link_range);
 312                             // this could just be a normal link
 313                             continue;
 314                         }
 315                     }
 316                     PathKind::Unknown => {
 317                         // try everything!
 318                         if let Some(macro_def) = macro_resolve(cx, path_str) {
 319                             if let Ok(type_def) = self.resolve(path_str, false, &current_item) {
 320                                 let (type_kind, article, type_disambig)
 321                                     = type_ns_kind(type_def.0, path_str);
 322                                 ambiguity_error(cx, &item.attrs, path_str,
 323                                                 article, type_kind, &type_disambig,
 324                                                 "a", "macro", &format!("macro@{}", path_str));
 325                                 continue;
 326                             } else if let Ok(value_def) = self.resolve(path_str,
 327                                                                        true,
 328                                                                        &current_item) {
 329                                 let (value_kind, value_disambig)
 330                                     = value_ns_kind(value_def.0, path_str)
 331                                         .expect("struct and mod cases should have been \
 332                                                  caught in previous branch");
 333                                 ambiguity_error(cx, &item.attrs, path_str,
 334                                                 "a", value_kind, &value_disambig,
 335                                                 "a", "macro", &format!("macro@{}", path_str));
 336                             }
 337                             (macro_def, None)
 338                         } else if let Ok(type_def) = self.resolve(path_str, false, &current_item) {
 339                             // It is imperative we search for not-a-value first
 340                             // Otherwise we will find struct ctors for when we are looking
 341                             // for structs, and the link won't work.
 342                             // if there is something in both namespaces
 343                             if let Ok(value_def) = self.resolve(path_str, true, &current_item) {
 344                                 let kind = value_ns_kind(value_def.0, path_str);
 345                                 if let Some((value_kind, value_disambig)) = kind {
 346                                     let (type_kind, article, type_disambig)
 347                                         = type_ns_kind(type_def.0, path_str);
 348                                     ambiguity_error(cx, &item.attrs, path_str,
 349                                                     article, type_kind, &type_disambig,
 350                                                     "a", value_kind, &value_disambig);
 351                                     continue;
 352                                 }
 353                             }
 354                             type_def
 355                         } else if let Ok(value_def) = self.resolve(path_str, true, &current_item) {
 356                             value_def
 357                         } else {
 358                             resolution_failure(cx, &item.attrs, path_str, &dox, link_range);
 359                             // this could just be a normal link
 360                             continue;
 361                         }
 362                     }
 363                     PathKind::Macro => {
 364                         if let Some(def) = macro_resolve(cx, path_str) {
 365                             (def, None)
 366                         } else {
 367                             resolution_failure(cx, &item.attrs, path_str, &dox, link_range);
 368                             continue
 369                         }
 370                     }
 371                 }
 372             };
 373
 374             if let Def::PrimTy(_) = def {
 375                 item.attrs.links.push((ori_link, None, fragment));
 376             } else {
 377                 let id = register_def(cx, def);
 378                 item.attrs.links.push((ori_link, Some(id), fragment));
 379             }
 380         }
 381
 382         if item.is_mod() && !item.attrs.inner_docs {
 383             self.mod_ids.push(item_node_id.unwrap());
 384         }
 385
 386         if item.is_mod() {
 387             let ret = self.fold_item_recur(item);
 388
 389             self.mod_ids.pop();
 390
 391             ret
 392         } else {
 393             self.fold_item_recur(item)
 394         }
 395     }
 396 }
 397
 398 /// Resolve a string as a macro
 399 fn macro_resolve(cx: &DocContext, path_str: &str) -> Option<Def> {
 400     use syntax::ext::base::{MacroKind, SyntaxExtension};
 401     use syntax::ext::hygiene::Mark;
 402     let segment = ast::PathSegment::from_ident(Ident::from_str(path_str));
 403     let path = ast::Path { segments: vec![segment], span: DUMMY_SP };
 404     let mut resolver = cx.resolver.borrow_mut();
 405     let mark = Mark::root();
 406     if let Ok(def) = resolver.resolve_macro_to_def_inner(&path, MacroKind::Bang, mark, &[], false) {
 407         if let SyntaxExtension::DeclMacro { .. } = *resolver.get_macro(def) {
 408             return Some(def);
 409         }
 410     }
 411     if let Some(def) = resolver.all_macros.get(&Symbol::intern(path_str)) {
 412         return Some(*def);
 413     }
 414     None
 415 }
 416
 417 fn span_of_attrs(attrs: &Attributes) -> syntax_pos::Span {
 418     if attrs.doc_strings.is_empty() {
 419         return DUMMY_SP;
 420     }
 421     let start = attrs.doc_strings[0].span();
 422     let end = attrs.doc_strings.last().expect("No doc strings provided").span();
 423     start.to(end)
 424 }
 425
 426 fn resolution_failure(
 427     cx: &DocContext,
 428     attrs: &Attributes,
 429     path_str: &str,
 430     dox: &str,
 431     link_range: Option<Range<usize>>,
 432 ) {
 433     let sp = span_of_attrs(attrs);
 434     let msg = format!("`[{}]` cannot be resolved, ignoring it...", path_str);
 435
 436     let code_dox = sp.to_src(cx);
 437
 438     let doc_comment_padding = 3;
 439     let mut diag = if let Some(link_range) = link_range {
 440         // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
 441         //                       ^    ~~~~~~
 442         //                       |    link_range
 443         //                       last_new_line_offset
 444
 445         let mut diag;
 446         if dox.lines().count() == code_dox.lines().count() {
 447             let line_offset = dox[..link_range.start].lines().count();
 448             // The span starts in the `///`, so we don't have to account for the leading whitespace
 449             let code_dox_len = if line_offset <= 1 {
 450                 doc_comment_padding
 451             } else {
 452                 // The first `///`
 453                 doc_comment_padding +
 454                     // Each subsequent leading whitespace and `///`
 455                     code_dox.lines().skip(1).take(line_offset - 1).fold(0, |sum, line| {
 456                         sum + doc_comment_padding + line.len() - line.trim().len()
 457                     })
 458             };
 459
 460             // Extract the specific span
 461             let sp = sp.from_inner_byte_pos(
 462                 link_range.start + code_dox_len,
 463                 link_range.end + code_dox_len,
 464             );
 465
 466             diag = cx.tcx.struct_span_lint_node(lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 467                                                 NodeId::new(0),
 468                                                 sp,
 469                                                 &msg);
 470             diag.span_label(sp, "cannot be resolved, ignoring");
 471         } else {
 472             diag = cx.tcx.struct_span_lint_node(lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 473                                                 NodeId::new(0),
 474                                                 sp,
 475                                                 &msg);
 476
 477             let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
 478             let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
 479
 480             // Print the line containing the `link_range` and manually mark it with '^'s
 481             diag.note(&format!(
 482                 "the link appears in this line:\n\n{line}\n\
 483                  {indicator: <before$}{indicator:^<found$}",
 484                 line=line,
 485                 indicator="",
 486                 before=link_range.start - last_new_line_offset,
 487                 found=link_range.len(),
 488             ));
 489         }
 490         diag
 491     } else {
 492         cx.tcx.struct_span_lint_node(lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
 493                                      NodeId::new(0),
 494                                      sp,
 495                                      &msg)
 496     };
 497     diag.help("to escape `[` and `]` characters, just add '\\' before them like \
 498                `\\[` or `\\]`");
 499     diag.emit();
 500 }
 501
 502 fn ambiguity_error(cx: &DocContext, attrs: &Attributes,
 503                    path_str: &str,
 504                    article1: &str, kind1: &str, disambig1: &str,
 505                    article2: &str, kind2: &str, disambig2: &str) {
 506     let sp = span_of_attrs(attrs);
 507     cx.sess()
 508       .struct_span_warn(sp,
 509                         &format!("`{}` is both {} {} and {} {}",
 510                                  path_str, article1, kind1,
 511                                  article2, kind2))
 512       .help(&format!("try `{}` if you want to select the {}, \
 513                       or `{}` if you want to \
 514                       select the {}",
 515                       disambig1, kind1, disambig2,
 516                       kind2))
 517       .emit();
 518 }
 519
 520 /// Given a def, returns its name and disambiguator
 521 /// for a value namespace
 522 ///
 523 /// Returns None for things which cannot be ambiguous since
 524 /// they exist in both namespaces (structs and modules)
 525 fn value_ns_kind(def: Def, path_str: &str) -> Option<(&'static str, String)> {
 526     match def {
 527         // structs, variants, and mods exist in both namespaces. skip them
 528         Def::StructCtor(..) | Def::Mod(..) | Def::Variant(..) | Def::VariantCtor(..) => None,
 529         Def::Fn(..)
 530             => Some(("function", format!("{}()", path_str))),
 531         Def::Method(..)
 532             => Some(("method", format!("{}()", path_str))),
 533         Def::Const(..)
 534             => Some(("const", format!("const@{}", path_str))),
 535         Def::Static(..)
 536             => Some(("static", format!("static@{}", path_str))),
 537         _ => Some(("value", format!("value@{}", path_str))),
 538     }
 539 }
 540
 541 /// Given a def, returns its name, the article to be used, and a disambiguator
 542 /// for the type namespace
 543 fn type_ns_kind(def: Def, path_str: &str) -> (&'static str, &'static str, String) {
 544     let (kind, article) = match def {
 545         // we can still have non-tuple structs
 546         Def::Struct(..) => ("struct", "a"),
 547         Def::Enum(..) => ("enum", "an"),
 548         Def::Trait(..) => ("trait", "a"),
 549         Def::Union(..) => ("union", "a"),
 550         _ => ("type", "a"),
 551     };
 552     (kind, article, format!("{}@{}", kind, path_str))
 553 }
 554
 555 /// Given an enum variant's def, return the def of its enum and the associated fragment
 556 fn handle_variant(cx: &DocContext, def: Def) -> Result<(Def, Option<String>), ()> {
 557     use rustc::ty::DefIdTree;
 558
 559     let parent = if let Some(parent) = cx.tcx.parent(def.def_id()) {
 560         parent
 561     } else {
 562         return Err(())
 563     };
 564     let parent_def = Def::Enum(parent);
 565     let variant = cx.tcx.expect_variant_def(def);
 566     Ok((parent_def, Some(format!("{}.v", variant.name))))
 567 }
 568
 569 const PRIMITIVES: &[(&str, Def)] = &[
 570     ("u8",    Def::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U8))),
 571     ("u16",   Def::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U16))),
 572     ("u32",   Def::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U32))),
 573     ("u64",   Def::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U64))),
 574     ("u128",  Def::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::U128))),
 575     ("usize", Def::PrimTy(hir::PrimTy::Uint(syntax::ast::UintTy::Usize))),
 576     ("i8",    Def::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I8))),
 577     ("i16",   Def::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I16))),
 578     ("i32",   Def::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I32))),
 579     ("i64",   Def::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I64))),
 580     ("i128",  Def::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::I128))),
 581     ("isize", Def::PrimTy(hir::PrimTy::Int(syntax::ast::IntTy::Isize))),
 582     ("f32",   Def::PrimTy(hir::PrimTy::Float(syntax::ast::FloatTy::F32))),
 583     ("f64",   Def::PrimTy(hir::PrimTy::Float(syntax::ast::FloatTy::F64))),
 584     ("str",   Def::PrimTy(hir::PrimTy::Str)),
 585     ("bool",  Def::PrimTy(hir::PrimTy::Bool)),
 586     ("char",  Def::PrimTy(hir::PrimTy::Char)),
 587 ];
 588
 589 fn is_primitive(path_str: &str, is_val: bool) -> Option<Def> {
 590     if is_val {
 591         None
 592     } else {
 593         PRIMITIVES.iter().find(|x| x.0 == path_str).map(|x| x.1)
 594     }
 595 }