src/librustdoc/html/format.rs

   1 // Copyright 2013-2014 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 //! HTML formatting module
  12 //!
  13 //! This module contains a large number of `fmt::Display` implementations for
  14 //! various types in `rustdoc::clean`. These implementations all currently
  15 //! assume that HTML output is desired, although it may be possible to redesign
  16 //! them in the future to instead emit any format desired.
  17
  18 use std::fmt;
  19 use std::iter::repeat;
  20
  21 use rustc::hir::def_id::DefId;
  22 use rustc_target::spec::abi::Abi;
  23 use rustc::hir;
  24
  25 use clean::{self, PrimitiveType};
  26 use core::DocAccessLevels;
  27 use html::item_type::ItemType;
  28 use html::render::{self, cache, CURRENT_LOCATION_KEY};
  29
  30 /// Helper to render an optional visibility with a space after it (if the
  31 /// visibility is preset)
  32 #[derive(Copy, Clone)]
  33 pub struct VisSpace<'a>(pub &'a Option<clean::Visibility>);
  34 /// Similarly to VisSpace, this structure is used to render a function style with a
  35 /// space after it.
  36 #[derive(Copy, Clone)]
  37 pub struct UnsafetySpace(pub hir::Unsafety);
  38 /// Similarly to VisSpace, this structure is used to render a function constness
  39 /// with a space after it.
  40 #[derive(Copy, Clone)]
  41 pub struct ConstnessSpace(pub hir::Constness);
  42 /// Similar to VisSpace, but used for mutability
  43 #[derive(Copy, Clone)]
  44 pub struct MutableSpace(pub clean::Mutability);
  45 /// Similar to VisSpace, but used for mutability
  46 #[derive(Copy, Clone)]
  47 pub struct RawMutableSpace(pub clean::Mutability);
  48 /// Wrapper struct for emitting type parameter bounds.
  49 pub struct TyParamBounds<'a>(pub &'a [clean::TyParamBound]);
  50 /// Wrapper struct for emitting a comma-separated list of items
  51 pub struct CommaSep<'a, T: 'a>(pub &'a [T]);
  52 pub struct AbiSpace(pub Abi);
  53
  54 /// Wrapper struct for properly emitting a method declaration.
  55 pub struct Method<'a> {
  56     /// The declaration to emit.
  57     pub decl: &'a clean::FnDecl,
  58     /// The length of the function's "name", used to determine line-wrapping.
  59     pub name_len: usize,
  60     /// The number of spaces to indent each successive line with, if line-wrapping is necessary.
  61     pub indent: usize,
  62 }
  63
  64 /// Wrapper struct for emitting a where clause from Generics.
  65 pub struct WhereClause<'a>{
  66     /// The Generics from which to emit a where clause.
  67     pub gens: &'a clean::Generics,
  68     /// The number of spaces to indent each line with.
  69     pub indent: usize,
  70     /// Whether the where clause needs to add a comma and newline after the last bound.
  71     pub end_newline: bool,
  72 }
  73
  74 pub struct HRef<'a> {
  75     pub did: DefId,
  76     pub text: &'a str,
  77 }
  78
  79 impl<'a> VisSpace<'a> {
  80     pub fn get(self) -> &'a Option<clean::Visibility> {
  81         let VisSpace(v) = self; v
  82     }
  83 }
  84
  85 impl UnsafetySpace {
  86     pub fn get(&self) -> hir::Unsafety {
  87         let UnsafetySpace(v) = *self; v
  88     }
  89 }
  90
  91 impl ConstnessSpace {
  92     pub fn get(&self) -> hir::Constness {
  93         let ConstnessSpace(v) = *self; v
  94     }
  95 }
  96
  97 impl<'a, T: fmt::Display> fmt::Display for CommaSep<'a, T> {
  98     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  99         for (i, item) in self.0.iter().enumerate() {
 100             if i != 0 { write!(f, ", ")?; }
 101             fmt::Display::fmt(item, f)?;
 102         }
 103         Ok(())
 104     }
 105 }
 106
 107 impl<'a> fmt::Display for TyParamBounds<'a> {
 108     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 109         let &TyParamBounds(bounds) = self;
 110         for (i, bound) in bounds.iter().enumerate() {
 111             if i > 0 {
 112                 f.write_str(" + ")?;
 113             }
 114             fmt::Display::fmt(bound, f)?;
 115         }
 116         Ok(())
 117     }
 118 }
 119
 120 impl fmt::Display for clean::GenericParamDef {
 121     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 122         match *self {
 123             clean::GenericParamDef::Lifetime(ref lp) => write!(f, "{}", lp),
 124             clean::GenericParamDef::Type(ref tp) => {
 125                 f.write_str(&tp.name)?;
 126
 127                 if !tp.bounds.is_empty() {
 128                     if f.alternate() {
 129                         write!(f, ": {:#}", TyParamBounds(&tp.bounds))?;
 130                     } else {
 131                         write!(f, ":&nbsp;{}", TyParamBounds(&tp.bounds))?;
 132                     }
 133                 }
 134
 135                 if let Some(ref ty) = tp.default {
 136                     if f.alternate() {
 137                         write!(f, " = {:#}", ty)?;
 138                     } else {
 139                         write!(f, "&nbsp;=&nbsp;{}", ty)?;
 140                     }
 141                 }
 142
 143                 Ok(())
 144             }
 145         }
 146     }
 147 }
 148
 149 impl fmt::Display for clean::Generics {
 150     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 151         let real_params = self.params
 152             .iter()
 153             .filter(|p| !p.is_synthetic_type_param())
 154             .collect::<Vec<_>>();
 155         if real_params.is_empty() {
 156             return Ok(());
 157         }
 158         if f.alternate() {
 159             write!(f, "<{:#}>", CommaSep(&real_params))
 160         } else {
 161             write!(f, "&lt;{}&gt;", CommaSep(&real_params))
 162         }
 163     }
 164 }
 165
 166 impl<'a> fmt::Display for WhereClause<'a> {
 167     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 168         let &WhereClause { gens, indent, end_newline } = self;
 169         if gens.where_predicates.is_empty() {
 170             return Ok(());
 171         }
 172         let mut clause = String::new();
 173         if f.alternate() {
 174             clause.push_str(" where");
 175         } else {
 176             if end_newline {
 177                 clause.push_str(" <span class=\"where fmt-newline\">where");
 178             } else {
 179                 clause.push_str(" <span class=\"where\">where");
 180             }
 181         }
 182         for (i, pred) in gens.where_predicates.iter().enumerate() {
 183             if f.alternate() {
 184                 clause.push(' ');
 185             } else {
 186                 clause.push_str("<br>");
 187             }
 188
 189             match pred {
 190                 &clean::WherePredicate::BoundPredicate { ref ty, ref bounds } => {
 191                     let bounds = bounds;
 192                     if f.alternate() {
 193                         clause.push_str(&format!("{:#}: {:#}", ty, TyParamBounds(bounds)));
 194                     } else {
 195                         clause.push_str(&format!("{}: {}", ty, TyParamBounds(bounds)));
 196                     }
 197                 }
 198                 &clean::WherePredicate::RegionPredicate { ref lifetime,
 199                                                           ref bounds } => {
 200                     clause.push_str(&format!("{}: ", lifetime));
 201                     for (i, lifetime) in bounds.iter().enumerate() {
 202                         if i > 0 {
 203                             clause.push_str(" + ");
 204                         }
 205
 206                         clause.push_str(&format!("{}", lifetime));
 207                     }
 208                 }
 209                 &clean::WherePredicate::EqPredicate { ref lhs, ref rhs } => {
 210                     if f.alternate() {
 211                         clause.push_str(&format!("{:#} == {:#}", lhs, rhs));
 212                     } else {
 213                         clause.push_str(&format!("{} == {}", lhs, rhs));
 214                     }
 215                 }
 216             }
 217
 218             if i < gens.where_predicates.len() - 1 || end_newline {
 219                 clause.push(',');
 220             }
 221         }
 222
 223         if end_newline {
 224             // add a space so stripping <br> tags and breaking spaces still renders properly
 225             if f.alternate() {
 226                 clause.push(' ');
 227             } else {
 228                 clause.push_str("&nbsp;");
 229             }
 230         }
 231
 232         if !f.alternate() {
 233             clause.push_str("</span>");
 234             let padding = repeat("&nbsp;").take(indent + 4).collect::<String>();
 235             clause = clause.replace("<br>", &format!("<br>{}", padding));
 236             clause.insert_str(0, &repeat("&nbsp;").take(indent.saturating_sub(1))
 237                                                   .collect::<String>());
 238             if !end_newline {
 239                 clause.insert_str(0, "<br>");
 240             }
 241         }
 242         write!(f, "{}", clause)
 243     }
 244 }
 245
 246 impl fmt::Display for clean::Lifetime {
 247     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 248         f.write_str(self.get_ref())?;
 249         Ok(())
 250     }
 251 }
 252
 253 impl fmt::Display for clean::PolyTrait {
 254     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 255         if !self.generic_params.is_empty() {
 256             if f.alternate() {
 257                 write!(f, "for<{:#}> ", CommaSep(&self.generic_params))?;
 258             } else {
 259                 write!(f, "for&lt;{}&gt; ", CommaSep(&self.generic_params))?;
 260             }
 261         }
 262         if f.alternate() {
 263             write!(f, "{:#}", self.trait_)
 264         } else {
 265             write!(f, "{}", self.trait_)
 266         }
 267     }
 268 }
 269
 270 impl fmt::Display for clean::TyParamBound {
 271     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 272         match *self {
 273             clean::RegionBound(ref lt) => {
 274                 write!(f, "{}", *lt)
 275             }
 276             clean::TraitBound(ref ty, modifier) => {
 277                 let modifier_str = match modifier {
 278                     hir::TraitBoundModifier::None => "",
 279                     hir::TraitBoundModifier::Maybe => "?",
 280                 };
 281                 if f.alternate() {
 282                     write!(f, "{}{:#}", modifier_str, *ty)
 283                 } else {
 284                     write!(f, "{}{}", modifier_str, *ty)
 285                 }
 286             }
 287         }
 288     }
 289 }
 290
 291 impl fmt::Display for clean::PathParameters {
 292     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 293         match *self {
 294             clean::PathParameters::AngleBracketed {
 295                 ref lifetimes, ref types, ref bindings
 296             } => {
 297                 if !lifetimes.is_empty() || !types.is_empty() || !bindings.is_empty() {
 298                     if f.alternate() {
 299                         f.write_str("<")?;
 300                     } else {
 301                         f.write_str("&lt;")?;
 302                     }
 303                     let mut comma = false;
 304                     for lifetime in lifetimes {
 305                         if comma {
 306                             f.write_str(", ")?;
 307                         }
 308                         comma = true;
 309                         write!(f, "{}", *lifetime)?;
 310                     }
 311                     for ty in types {
 312                         if comma {
 313                             f.write_str(", ")?;
 314                         }
 315                         comma = true;
 316                         if f.alternate() {
 317                             write!(f, "{:#}", *ty)?;
 318                         } else {
 319                             write!(f, "{}", *ty)?;
 320                         }
 321                     }
 322                     for binding in bindings {
 323                         if comma {
 324                             f.write_str(", ")?;
 325                         }
 326                         comma = true;
 327                         if f.alternate() {
 328                             write!(f, "{:#}", *binding)?;
 329                         } else {
 330                             write!(f, "{}", *binding)?;
 331                         }
 332                     }
 333                     if f.alternate() {
 334                         f.write_str(">")?;
 335                     } else {
 336                         f.write_str("&gt;")?;
 337                     }
 338                 }
 339             }
 340             clean::PathParameters::Parenthesized { ref inputs, ref output } => {
 341                 f.write_str("(")?;
 342                 let mut comma = false;
 343                 for ty in inputs {
 344                     if comma {
 345                         f.write_str(", ")?;
 346                     }
 347                     comma = true;
 348                     if f.alternate() {
 349                         write!(f, "{:#}", *ty)?;
 350                     } else {
 351                         write!(f, "{}", *ty)?;
 352                     }
 353                 }
 354                 f.write_str(")")?;
 355                 if let Some(ref ty) = *output {
 356                     if f.alternate() {
 357                         write!(f, " -> {:#}", ty)?;
 358                     } else {
 359                         write!(f, " -&gt; {}", ty)?;
 360                     }
 361                 }
 362             }
 363         }
 364         Ok(())
 365     }
 366 }
 367
 368 impl fmt::Display for clean::PathSegment {
 369     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 370         f.write_str(&self.name)?;
 371         if f.alternate() {
 372             write!(f, "{:#}", self.params)
 373         } else {
 374             write!(f, "{}", self.params)
 375         }
 376     }
 377 }
 378
 379 impl fmt::Display for clean::Path {
 380     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 381         if self.global {
 382             f.write_str("::")?
 383         }
 384
 385         for (i, seg) in self.segments.iter().enumerate() {
 386             if i > 0 {
 387                 f.write_str("::")?
 388             }
 389             if f.alternate() {
 390                 write!(f, "{:#}", seg)?;
 391             } else {
 392                 write!(f, "{}", seg)?;
 393             }
 394         }
 395         Ok(())
 396     }
 397 }
 398
 399 pub fn href(did: DefId) -> Option<(String, ItemType, Vec<String>)> {
 400     let cache = cache();
 401     if !did.is_local() && !cache.access_levels.is_doc_reachable(did) {
 402         return None
 403     }
 404
 405     let loc = CURRENT_LOCATION_KEY.with(|l| l.borrow().clone());
 406     let (fqp, shortty, mut url) = match cache.paths.get(&did) {
 407         Some(&(ref fqp, shortty)) => {
 408             (fqp, shortty, repeat("../").take(loc.len()).collect())
 409         }
 410         None => {
 411             let &(ref fqp, shortty) = cache.external_paths.get(&did)?;
 412             (fqp, shortty, match cache.extern_locations[&did.krate] {
 413                 (.., render::Remote(ref s)) => s.to_string(),
 414                 (.., render::Local) => repeat("../").take(loc.len()).collect(),
 415                 (.., render::Unknown) => return None,
 416             })
 417         }
 418     };
 419     for component in &fqp[..fqp.len() - 1] {
 420         url.push_str(component);
 421         url.push_str("/");
 422     }
 423     match shortty {
 424         ItemType::Module => {
 425             url.push_str(fqp.last().unwrap());
 426             url.push_str("/index.html");
 427         }
 428         _ => {
 429             url.push_str(shortty.css_class());
 430             url.push_str(".");
 431             url.push_str(fqp.last().unwrap());
 432             url.push_str(".html");
 433         }
 434     }
 435     Some((url, shortty, fqp.to_vec()))
 436 }
 437
 438 /// Used when rendering a `ResolvedPath` structure. This invokes the `path`
 439 /// rendering function with the necessary arguments for linking to a local path.
 440 fn resolved_path(w: &mut fmt::Formatter, did: DefId, path: &clean::Path,
 441                  print_all: bool, use_absolute: bool) -> fmt::Result {
 442     let last = path.segments.last().unwrap();
 443
 444     if print_all {
 445         for seg in &path.segments[..path.segments.len() - 1] {
 446             write!(w, "{}::", seg.name)?;
 447         }
 448     }
 449     if w.alternate() {
 450         write!(w, "{:#}{:#}", HRef::new(did, &last.name), last.params)?;
 451     } else {
 452         let path = if use_absolute {
 453             match href(did) {
 454                 Some((_, _, fqp)) => {
 455                     format!("{}::{}",
 456                             fqp[..fqp.len() - 1].join("::"),
 457                             HRef::new(did, fqp.last().unwrap()))
 458                 }
 459                 None => format!("{}", HRef::new(did, &last.name)),
 460             }
 461         } else {
 462             format!("{}", HRef::new(did, &last.name))
 463         };
 464         write!(w, "{}{}", path, last.params)?;
 465     }
 466     Ok(())
 467 }
 468
 469 fn primitive_link(f: &mut fmt::Formatter,
 470                   prim: clean::PrimitiveType,
 471                   name: &str) -> fmt::Result {
 472     let m = cache();
 473     let mut needs_termination = false;
 474     if !f.alternate() {
 475         match m.primitive_locations.get(&prim) {
 476             Some(&def_id) if def_id.is_local() => {
 477                 let len = CURRENT_LOCATION_KEY.with(|s| s.borrow().len());
 478                 let len = if len == 0 {0} else {len - 1};
 479                 write!(f, "<a class=\"primitive\" href=\"{}primitive.{}.html\">",
 480                        repeat("../").take(len).collect::<String>(),
 481                        prim.to_url_str())?;
 482                 needs_termination = true;
 483             }
 484             Some(&def_id) => {
 485                 let loc = match m.extern_locations[&def_id.krate] {
 486                     (ref cname, _, render::Remote(ref s)) => {
 487                         Some((cname, s.to_string()))
 488                     }
 489                     (ref cname, _, render::Local) => {
 490                         let len = CURRENT_LOCATION_KEY.with(|s| s.borrow().len());
 491                         Some((cname, repeat("../").take(len).collect::<String>()))
 492                     }
 493                     (.., render::Unknown) => None,
 494                 };
 495                 if let Some((cname, root)) = loc {
 496                     write!(f, "<a class=\"primitive\" href=\"{}{}/primitive.{}.html\">",
 497                            root,
 498                            cname,
 499                            prim.to_url_str())?;
 500                     needs_termination = true;
 501                 }
 502             }
 503             None => {}
 504         }
 505     }
 506     write!(f, "{}", name)?;
 507     if needs_termination {
 508         write!(f, "</a>")?;
 509     }
 510     Ok(())
 511 }
 512
 513 /// Helper to render type parameters
 514 fn tybounds(w: &mut fmt::Formatter,
 515             typarams: &Option<Vec<clean::TyParamBound>>) -> fmt::Result {
 516     match *typarams {
 517         Some(ref params) => {
 518             for param in params {
 519                 write!(w, " + ")?;
 520                 fmt::Display::fmt(param, w)?;
 521             }
 522             Ok(())
 523         }
 524         None => Ok(())
 525     }
 526 }
 527
 528 impl<'a> HRef<'a> {
 529     pub fn new(did: DefId, text: &'a str) -> HRef<'a> {
 530         HRef { did: did, text: text }
 531     }
 532 }
 533
 534 impl<'a> fmt::Display for HRef<'a> {
 535     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 536         match href(self.did) {
 537             Some((url, shortty, fqp)) => if !f.alternate() {
 538                 write!(f, "<a class=\"{}\" href=\"{}\" title=\"{} {}\">{}</a>",
 539                        shortty, url, shortty, fqp.join("::"), self.text)
 540             } else {
 541                 write!(f, "{}", self.text)
 542             },
 543             _ => write!(f, "{}", self.text),
 544         }
 545     }
 546 }
 547
 548 fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt::Result {
 549     match *t {
 550         clean::Generic(ref name) => {
 551             f.write_str(name)
 552         }
 553         clean::ResolvedPath{ did, ref typarams, ref path, is_generic } => {
 554             // Paths like T::Output and Self::Output should be rendered with all segments
 555             resolved_path(f, did, path, is_generic, use_absolute)?;
 556             tybounds(f, typarams)
 557         }
 558         clean::Infer => write!(f, "_"),
 559         clean::Primitive(prim) => primitive_link(f, prim, prim.as_str()),
 560         clean::BareFunction(ref decl) => {
 561             if f.alternate() {
 562                 write!(f, "{}{:#}fn{:#}{:#}",
 563                        UnsafetySpace(decl.unsafety),
 564                        AbiSpace(decl.abi),
 565                        CommaSep(&decl.generic_params),
 566                        decl.decl)
 567             } else {
 568                 write!(f, "{}{}", UnsafetySpace(decl.unsafety), AbiSpace(decl.abi))?;
 569                 primitive_link(f, PrimitiveType::Fn, "fn")?;
 570                 write!(f, "{}{}", CommaSep(&decl.generic_params), decl.decl)
 571             }
 572         }
 573         clean::Tuple(ref typs) => {
 574             match &typs[..] {
 575                 &[] => primitive_link(f, PrimitiveType::Unit, "()"),
 576                 &[ref one] => {
 577                     primitive_link(f, PrimitiveType::Tuple, "(")?;
 578                     //carry f.alternate() into this display w/o branching manually
 579                     fmt::Display::fmt(one, f)?;
 580                     primitive_link(f, PrimitiveType::Tuple, ",)")
 581                 }
 582                 many => {
 583                     primitive_link(f, PrimitiveType::Tuple, "(")?;
 584                     fmt::Display::fmt(&CommaSep(many), f)?;
 585                     primitive_link(f, PrimitiveType::Tuple, ")")
 586                 }
 587             }
 588         }
 589         clean::Slice(ref t) => {
 590             primitive_link(f, PrimitiveType::Slice, "[")?;
 591             fmt::Display::fmt(t, f)?;
 592             primitive_link(f, PrimitiveType::Slice, "]")
 593         }
 594         clean::Array(ref t, ref n) => {
 595             primitive_link(f, PrimitiveType::Array, "[")?;
 596             fmt::Display::fmt(t, f)?;
 597             primitive_link(f, PrimitiveType::Array, &format!("; {}]", n))
 598         }
 599         clean::Never => primitive_link(f, PrimitiveType::Never, "!"),
 600         clean::RawPointer(m, ref t) => {
 601             match **t {
 602                 clean::Generic(_) | clean::ResolvedPath {is_generic: true, ..} => {
 603                     if f.alternate() {
 604                         primitive_link(f, clean::PrimitiveType::RawPointer,
 605                                        &format!("*{}{:#}", RawMutableSpace(m), t))
 606                     } else {
 607                         primitive_link(f, clean::PrimitiveType::RawPointer,
 608                                        &format!("*{}{}", RawMutableSpace(m), t))
 609                     }
 610                 }
 611                 _ => {
 612                     primitive_link(f, clean::PrimitiveType::RawPointer,
 613                                    &format!("*{}", RawMutableSpace(m)))?;
 614                     fmt::Display::fmt(t, f)
 615                 }
 616             }
 617         }
 618         clean::BorrowedRef{ lifetime: ref l, mutability, type_: ref ty} => {
 619             let lt = match *l {
 620                 Some(ref l) => format!("{} ", *l),
 621                 _ => "".to_string(),
 622             };
 623             let m = MutableSpace(mutability);
 624             let amp = if f.alternate() {
 625                 "&".to_string()
 626             } else {
 627                 "&amp;".to_string()
 628             };
 629             match **ty {
 630                 clean::Slice(ref bt) => { // BorrowedRef{ ... Slice(T) } is &[T]
 631                     match **bt {
 632                         clean::Generic(_) => {
 633                             if f.alternate() {
 634                                 primitive_link(f, PrimitiveType::Slice,
 635                                     &format!("{}{}{}[{:#}]", amp, lt, m, **bt))
 636                             } else {
 637                                 primitive_link(f, PrimitiveType::Slice,
 638                                     &format!("{}{}{}[{}]", amp, lt, m, **bt))
 639                             }
 640                         }
 641                         _ => {
 642                             primitive_link(f, PrimitiveType::Slice,
 643                                            &format!("{}{}{}[", amp, lt, m))?;
 644                             if f.alternate() {
 645                                 write!(f, "{:#}", **bt)?;
 646                             } else {
 647                                 write!(f, "{}", **bt)?;
 648                             }
 649                             primitive_link(f, PrimitiveType::Slice, "]")
 650                         }
 651                     }
 652                 }
 653                 clean::ResolvedPath { typarams: Some(ref v), .. } if !v.is_empty() => {
 654                     write!(f, "{}{}{}(", amp, lt, m)?;
 655                     fmt_type(&ty, f, use_absolute)?;
 656                     write!(f, ")")
 657                 }
 658                 clean::Generic(..) => {
 659                     primitive_link(f, PrimitiveType::Reference,
 660                                    &format!("{}{}{}", amp, lt, m))?;
 661                     fmt_type(&ty, f, use_absolute)
 662                 }
 663                 _ => {
 664                     write!(f, "{}{}{}", amp, lt, m)?;
 665                     fmt_type(&ty, f, use_absolute)
 666                 }
 667             }
 668         }
 669         clean::ImplTrait(ref bounds) => {
 670             write!(f, "impl {}", TyParamBounds(bounds))
 671         }
 672         clean::QPath { ref name, ref self_type, ref trait_ } => {
 673             let should_show_cast = match *trait_ {
 674                 box clean::ResolvedPath { ref path, .. } => {
 675                     !path.segments.is_empty() && !self_type.is_self_type()
 676                 }
 677                 _ => true,
 678             };
 679             if f.alternate() {
 680                 if should_show_cast {
 681                     write!(f, "<{:#} as {:#}>::", self_type, trait_)?
 682                 } else {
 683                     write!(f, "{:#}::", self_type)?
 684                 }
 685             } else {
 686                 if should_show_cast {
 687                     write!(f, "&lt;{} as {}&gt;::", self_type, trait_)?
 688                 } else {
 689                     write!(f, "{}::", self_type)?
 690                 }
 691             };
 692             match *trait_ {
 693                 // It's pretty unsightly to look at `<A as B>::C` in output, and
 694                 // we've got hyperlinking on our side, so try to avoid longer
 695                 // notation as much as possible by making `C` a hyperlink to trait
 696                 // `B` to disambiguate.
 697                 //
 698                 // FIXME: this is still a lossy conversion and there should probably
 699                 //        be a better way of representing this in general? Most of
 700                 //        the ugliness comes from inlining across crates where
 701                 //        everything comes in as a fully resolved QPath (hard to
 702                 //        look at).
 703                 box clean::ResolvedPath { did, ref typarams, .. } => {
 704                     match href(did) {
 705                         Some((ref url, _, ref path)) if !f.alternate() => {
 706                             write!(f,
 707                                    "<a class=\"type\" href=\"{url}#{shortty}.{name}\" \
 708                                    title=\"type {path}::{name}\">{name}</a>",
 709                                    url = url,
 710                                    shortty = ItemType::AssociatedType,
 711                                    name = name,
 712                                    path = path.join("::"))?;
 713                         }
 714                         _ => write!(f, "{}", name)?,
 715                     }
 716
 717                     // FIXME: `typarams` are not rendered, and this seems bad?
 718                     drop(typarams);
 719                     Ok(())
 720                 }
 721                 _ => {
 722                     write!(f, "{}", name)
 723                 }
 724             }
 725         }
 726         clean::Unique(..) => {
 727             panic!("should have been cleaned")
 728         }
 729     }
 730 }
 731
 732 impl fmt::Display for clean::Type {
 733     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 734         fmt_type(self, f, false)
 735     }
 736 }
 737
 738 fn fmt_impl(i: &clean::Impl,
 739             f: &mut fmt::Formatter,
 740             link_trait: bool,
 741             use_absolute: bool) -> fmt::Result {
 742     if f.alternate() {
 743         write!(f, "impl{:#} ", i.generics)?;
 744     } else {
 745         write!(f, "impl{} ", i.generics)?;
 746     }
 747
 748     if let Some(ref ty) = i.trait_ {
 749         if i.polarity == Some(clean::ImplPolarity::Negative) {
 750             write!(f, "!")?;
 751         }
 752
 753         if link_trait {
 754             fmt::Display::fmt(ty, f)?;
 755         } else {
 756             match *ty {
 757                 clean::ResolvedPath { typarams: None, ref path, is_generic: false, .. } => {
 758                     let last = path.segments.last().unwrap();
 759                     fmt::Display::fmt(&last.name, f)?;
 760                     fmt::Display::fmt(&last.params, f)?;
 761                 }
 762                 _ => unreachable!(),
 763             }
 764         }
 765         write!(f, " for ")?;
 766     }
 767
 768     fmt_type(&i.for_, f, use_absolute)?;
 769
 770     fmt::Display::fmt(&WhereClause { gens: &i.generics, indent: 0, end_newline: true }, f)?;
 771     Ok(())
 772 }
 773
 774 impl fmt::Display for clean::Impl {
 775     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 776         fmt_impl(self, f, true, false)
 777     }
 778 }
 779
 780 // The difference from above is that trait is not hyperlinked.
 781 pub fn fmt_impl_for_trait_page(i: &clean::Impl,
 782                                f: &mut fmt::Formatter,
 783                                use_absolute: bool) -> fmt::Result {
 784     fmt_impl(i, f, false, use_absolute)
 785 }
 786
 787 impl fmt::Display for clean::Arguments {
 788     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 789         for (i, input) in self.values.iter().enumerate() {
 790             if !input.name.is_empty() {
 791                 write!(f, "{}: ", input.name)?;
 792             }
 793             if f.alternate() {
 794                 write!(f, "{:#}", input.type_)?;
 795             } else {
 796                 write!(f, "{}", input.type_)?;
 797             }
 798             if i + 1 < self.values.len() { write!(f, ", ")?; }
 799         }
 800         Ok(())
 801     }
 802 }
 803
 804 impl fmt::Display for clean::FunctionRetTy {
 805     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 806         match *self {
 807             clean::Return(clean::Tuple(ref tys)) if tys.is_empty() => Ok(()),
 808             clean::Return(ref ty) if f.alternate() => write!(f, " -> {:#}", ty),
 809             clean::Return(ref ty) => write!(f, " -&gt; {}", ty),
 810             clean::DefaultReturn => Ok(()),
 811         }
 812     }
 813 }
 814
 815 impl fmt::Display for clean::FnDecl {
 816     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 817         if self.variadic {
 818             if f.alternate() {
 819                 write!(f, "({args:#}, ...){arrow:#}", args = self.inputs, arrow = self.output)
 820             } else {
 821                 write!(f, "({args}, ...){arrow}", args = self.inputs, arrow = self.output)
 822             }
 823         } else {
 824             if f.alternate() {
 825                 write!(f, "({args:#}){arrow:#}", args = self.inputs, arrow = self.output)
 826             } else {
 827                 write!(f, "({args}){arrow}", args = self.inputs, arrow = self.output)
 828             }
 829         }
 830     }
 831 }
 832
 833 impl<'a> fmt::Display for Method<'a> {
 834     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 835         let &Method { decl, name_len, indent } = self;
 836         let amp = if f.alternate() { "&" } else { "&amp;" };
 837         let mut args = String::new();
 838         let mut args_plain = String::new();
 839         for (i, input) in decl.inputs.values.iter().enumerate() {
 840             if i == 0 {
 841                 args.push_str("<br>");
 842             }
 843
 844             if let Some(selfty) = input.to_self() {
 845                 match selfty {
 846                     clean::SelfValue => {
 847                         args.push_str("self");
 848                         args_plain.push_str("self");
 849                     }
 850                     clean::SelfBorrowed(Some(ref lt), mtbl) => {
 851                         args.push_str(&format!("{}{} {}self", amp, *lt, MutableSpace(mtbl)));
 852                         args_plain.push_str(&format!("&{} {}self", *lt, MutableSpace(mtbl)));
 853                     }
 854                     clean::SelfBorrowed(None, mtbl) => {
 855                         args.push_str(&format!("{}{}self", amp, MutableSpace(mtbl)));
 856                         args_plain.push_str(&format!("&{}self", MutableSpace(mtbl)));
 857                     }
 858                     clean::SelfExplicit(ref typ) => {
 859                         if f.alternate() {
 860                             args.push_str(&format!("self: {:#}", *typ));
 861                         } else {
 862                             args.push_str(&format!("self: {}", *typ));
 863                         }
 864                         args_plain.push_str(&format!("self: {:#}", *typ));
 865                     }
 866                 }
 867             } else {
 868                 if i > 0 {
 869                     args.push_str(" <br>");
 870                     args_plain.push_str(" ");
 871                 }
 872                 if !input.name.is_empty() {
 873                     args.push_str(&format!("{}: ", input.name));
 874                     args_plain.push_str(&format!("{}: ", input.name));
 875                 }
 876
 877                 if f.alternate() {
 878                     args.push_str(&format!("{:#}", input.type_));
 879                 } else {
 880                     args.push_str(&format!("{}", input.type_));
 881                 }
 882                 args_plain.push_str(&format!("{:#}", input.type_));
 883             }
 884             if i + 1 < decl.inputs.values.len() {
 885                 args.push(',');
 886                 args_plain.push(',');
 887             }
 888         }
 889
 890         if decl.variadic {
 891             args.push_str(",<br> ...");
 892             args_plain.push_str(", ...");
 893         }
 894
 895         let arrow_plain = format!("{:#}", decl.output);
 896         let arrow = if f.alternate() {
 897             format!("{:#}", decl.output)
 898         } else {
 899             format!("{}", decl.output)
 900         };
 901
 902         let pad = repeat(" ").take(name_len).collect::<String>();
 903         let plain = format!("{pad}({args}){arrow}",
 904                         pad = pad,
 905                         args = args_plain,
 906                         arrow = arrow_plain);
 907
 908         let output = if plain.len() > 80 {
 909             let full_pad = format!("<br>{}", repeat("&nbsp;").take(indent + 4).collect::<String>());
 910             let close_pad = format!("<br>{}", repeat("&nbsp;").take(indent).collect::<String>());
 911             format!("({args}{close}){arrow}",
 912                     args = args.replace("<br>", &full_pad),
 913                     close = close_pad,
 914                     arrow = arrow)
 915         } else {
 916             format!("({args}){arrow}", args = args.replace("<br>", ""), arrow = arrow)
 917         };
 918
 919         if f.alternate() {
 920             write!(f, "{}", output.replace("<br>", "\n"))
 921         } else {
 922             write!(f, "{}", output)
 923         }
 924     }
 925 }
 926
 927 impl<'a> fmt::Display for VisSpace<'a> {
 928     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 929         match *self.get() {
 930             Some(clean::Public) => write!(f, "pub "),
 931             Some(clean::Inherited) | None => Ok(())
 932         }
 933     }
 934 }
 935
 936 impl fmt::Display for UnsafetySpace {
 937     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 938         match self.get() {
 939             hir::Unsafety::Unsafe => write!(f, "unsafe "),
 940             hir::Unsafety::Normal => Ok(())
 941         }
 942     }
 943 }
 944
 945 impl fmt::Display for ConstnessSpace {
 946     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 947         match self.get() {
 948             hir::Constness::Const => write!(f, "const "),
 949             hir::Constness::NotConst => Ok(())
 950         }
 951     }
 952 }
 953
 954 impl fmt::Display for clean::Import {
 955     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 956         match *self {
 957             clean::Import::Simple(ref name, ref src) => {
 958                 if *name == src.path.last_name() {
 959                     write!(f, "use {};", *src)
 960                 } else {
 961                     write!(f, "use {} as {};", *src, *name)
 962                 }
 963             }
 964             clean::Import::Glob(ref src) => {
 965                 if src.path.segments.is_empty() {
 966                     write!(f, "use *;")
 967                 } else {
 968                     write!(f, "use {}::*;", *src)
 969                 }
 970             }
 971         }
 972     }
 973 }
 974
 975 impl fmt::Display for clean::ImportSource {
 976     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 977         match self.did {
 978             Some(did) => resolved_path(f, did, &self.path, true, false),
 979             _ => {
 980                 for (i, seg) in self.path.segments.iter().enumerate() {
 981                     if i > 0 {
 982                         write!(f, "::")?
 983                     }
 984                     write!(f, "{}", seg.name)?;
 985                 }
 986                 Ok(())
 987             }
 988         }
 989     }
 990 }
 991
 992 impl fmt::Display for clean::TypeBinding {
 993     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 994         if f.alternate() {
 995             write!(f, "{} = {:#}", self.name, self.ty)
 996         } else {
 997             write!(f, "{} = {}", self.name, self.ty)
 998         }
 999     }
1000 }
1001
1002 impl fmt::Display for MutableSpace {
1003     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1004         match *self {
1005             MutableSpace(clean::Immutable) => Ok(()),
1006             MutableSpace(clean::Mutable) => write!(f, "mut "),
1007         }
1008     }
1009 }
1010
1011 impl fmt::Display for RawMutableSpace {
1012     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1013         match *self {
1014             RawMutableSpace(clean::Immutable) => write!(f, "const "),
1015             RawMutableSpace(clean::Mutable) => write!(f, "mut "),
1016         }
1017     }
1018 }
1019
1020 impl fmt::Display for AbiSpace {
1021     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1022         let quot = if f.alternate() { "\"" } else { "&quot;" };
1023         match self.0 {
1024             Abi::Rust => Ok(()),
1025             abi => write!(f, "extern {0}{1}{0} ", quot, abi.name()),
1026         }
1027     }
1028 }