src/librustc/metadata/decoder.rs

   1 // Copyright 2012-2014 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 // Decoding metadata from a single crate's metadata
  12
  13 #![allow(non_camel_case_types)]
  14
  15 pub use self::DefLike::*;
  16 use self::Family::*;
  17
  18 use ast_map;
  19 use back::svh::Svh;
  20 use metadata::cstore::crate_metadata;
  21 use metadata::common::*;
  22 use metadata::csearch::MethodInfo;
  23 use metadata::csearch;
  24 use metadata::cstore;
  25 use metadata::encoder::def_to_u64;
  26 use metadata::tydecode::{parse_ty_data, parse_region_data,
  27                          parse_type_param_def_data, parse_bare_fn_ty_data,
  28                          parse_trait_ref_data, parse_predicate_data};
  29 use middle::def;
  30 use middle::lang_items;
  31 use middle::subst;
  32 use middle::ty::{ImplContainer, TraitContainer};
  33 use middle::ty::{self, Ty};
  34 use util::nodemap::FnvHashMap;
  35
  36 use std::cell::{Cell, RefCell};
  37 use std::collections::HashMap;
  38 use std::hash::{Hash, SipHasher, Hasher};
  39 use std::io::prelude::*;
  40 use std::io;
  41 use std::rc::Rc;
  42 use std::slice::bytes;
  43 use std::str;
  44
  45 use rbml::reader;
  46 use rbml;
  47 use serialize::Decodable;
  48 use syntax::attr;
  49 use syntax::parse::token::{IdentInterner, special_idents};
  50 use syntax::parse::token;
  51 use syntax::print::pprust;
  52 use syntax::ast;
  53 use syntax::codemap;
  54 use syntax::ptr::P;
  55
  56 pub type Cmd<'a> = &'a crate_metadata;
  57
  58 // A function that takes a def_id relative to the crate being searched and
  59 // returns a def_id relative to the compilation environment, i.e. if we hit a
  60 // def_id for an item defined in another crate, somebody needs to figure out
  61 // what crate that's in and give us a def_id that makes sense for the current
  62 // build.
  63
  64 fn u32_from_be_bytes(bytes: &[u8]) -> u32 {
  65     let mut b = [0; 4];
  66     bytes::copy_memory(&bytes[..4], &mut b);
  67     unsafe { (*(b.as_ptr() as *const u32)).to_be() }
  68 }
  69
  70 fn lookup_hash<'a, F>(d: rbml::Doc<'a>, mut eq_fn: F, hash: u64) -> Option<rbml::Doc<'a>> where
  71     F: FnMut(&[u8]) -> bool,
  72 {
  73     let index = reader::get_doc(d, tag_index);
  74     let table = reader::get_doc(index, tag_index_table);
  75     let hash_pos = table.start + (hash % 256 * 4) as usize;
  76     let pos = u32_from_be_bytes(&d.data[hash_pos..]) as usize;
  77     let tagged_doc = reader::doc_at(d.data, pos).unwrap();
  78
  79     reader::tagged_docs(tagged_doc.doc, tag_index_buckets_bucket_elt).find(|elt| {
  80         eq_fn(&elt.data[elt.start + 4 .. elt.end])
  81     }).map(|elt| {
  82         let pos = u32_from_be_bytes(&elt.data[elt.start..]) as usize;
  83         reader::doc_at(d.data, pos).unwrap().doc
  84     })
  85 }
  86
  87 pub fn maybe_find_item<'a>(item_id: ast::NodeId,
  88                            items: rbml::Doc<'a>) -> Option<rbml::Doc<'a>> {
  89     fn eq_item(bytes: &[u8], item_id: ast::NodeId) -> bool {
  90         u32_from_be_bytes(bytes) == item_id
  91     }
  92     let mut s = SipHasher::new_with_keys(0, 0);
  93     (item_id as i64).hash(&mut s);
  94     lookup_hash(items, |a| eq_item(a, item_id), s.finish())
  95 }
  96
  97 fn find_item<'a>(item_id: ast::NodeId, items: rbml::Doc<'a>) -> rbml::Doc<'a> {
  98     match maybe_find_item(item_id, items) {
  99        None => panic!("lookup_item: id not found: {}", item_id),
 100        Some(d) => d
 101     }
 102 }
 103
 104 // Looks up an item in the given metadata and returns an rbml doc pointing
 105 // to the item data.
 106 fn lookup_item<'a>(item_id: ast::NodeId, data: &'a [u8]) -> rbml::Doc<'a> {
 107     let items = reader::get_doc(rbml::Doc::new(data), tag_items);
 108     find_item(item_id, items)
 109 }
 110
 111 #[derive(PartialEq)]
 112 enum Family {
 113     ImmStatic,             // c
 114     MutStatic,             // b
 115     Fn,                    // f
 116     CtorFn,                // o
 117     StaticMethod,          // F
 118     Method,                // h
 119     Type,                  // y
 120     Mod,                   // m
 121     ForeignMod,            // n
 122     Enum,                  // t
 123     TupleVariant,          // v
 124     StructVariant,         // V
 125     Impl,                  // i
 126     DefaultImpl,              // d
 127     Trait,                 // I
 128     Struct,                // S
 129     PublicField,           // g
 130     InheritedField,        // N
 131     Constant,              // C
 132 }
 133
 134 fn item_family(item: rbml::Doc) -> Family {
 135     let fam = reader::get_doc(item, tag_items_data_item_family);
 136     match reader::doc_as_u8(fam) as char {
 137       'C' => Constant,
 138       'c' => ImmStatic,
 139       'b' => MutStatic,
 140       'f' => Fn,
 141       'o' => CtorFn,
 142       'F' => StaticMethod,
 143       'h' => Method,
 144       'y' => Type,
 145       'm' => Mod,
 146       'n' => ForeignMod,
 147       't' => Enum,
 148       'v' => TupleVariant,
 149       'V' => StructVariant,
 150       'i' => Impl,
 151       'd' => DefaultImpl,
 152       'I' => Trait,
 153       'S' => Struct,
 154       'g' => PublicField,
 155       'N' => InheritedField,
 156        c => panic!("unexpected family char: {}", c)
 157     }
 158 }
 159
 160 fn item_visibility(item: rbml::Doc) -> ast::Visibility {
 161     match reader::maybe_get_doc(item, tag_items_data_item_visibility) {
 162         None => ast::Public,
 163         Some(visibility_doc) => {
 164             match reader::doc_as_u8(visibility_doc) as char {
 165                 'y' => ast::Public,
 166                 'i' => ast::Inherited,
 167                 _ => panic!("unknown visibility character")
 168             }
 169         }
 170     }
 171 }
 172
 173 fn fn_constness(item: rbml::Doc) -> ast::Constness {
 174     match reader::maybe_get_doc(item, tag_items_data_item_constness) {
 175         None => ast::Constness::NotConst,
 176         Some(constness_doc) => {
 177             match reader::doc_as_u8(constness_doc) as char {
 178                 'c' => ast::Constness::Const,
 179                 'n' => ast::Constness::NotConst,
 180                 _ => panic!("unknown constness character")
 181             }
 182         }
 183     }
 184 }
 185
 186 fn item_sort(item: rbml::Doc) -> Option<char> {
 187     reader::tagged_docs(item, tag_item_trait_item_sort).nth(0).map(|doc| {
 188         doc.as_str_slice().as_bytes()[0] as char
 189     })
 190 }
 191
 192 fn item_symbol(item: rbml::Doc) -> String {
 193     reader::get_doc(item, tag_items_data_item_symbol).as_str().to_string()
 194 }
 195
 196 fn translated_def_id(cdata: Cmd, d: rbml::Doc) -> ast::DefId {
 197     let id = reader::doc_as_u64(d);
 198     let def_id = ast::DefId { krate: (id >> 32) as u32, node: id as u32 };
 199     translate_def_id(cdata, def_id)
 200 }
 201
 202 fn item_parent_item(cdata: Cmd, d: rbml::Doc) -> Option<ast::DefId> {
 203     reader::tagged_docs(d, tag_items_data_parent_item).nth(0).map(|did| {
 204         translated_def_id(cdata, did)
 205     })
 206 }
 207
 208 fn item_require_parent_item(cdata: Cmd, d: rbml::Doc) -> ast::DefId {
 209     translated_def_id(cdata, reader::get_doc(d, tag_items_data_parent_item))
 210 }
 211
 212 fn item_def_id(d: rbml::Doc, cdata: Cmd) -> ast::DefId {
 213     translated_def_id(cdata, reader::get_doc(d, tag_def_id))
 214 }
 215
 216 fn get_provided_source(d: rbml::Doc, cdata: Cmd) -> Option<ast::DefId> {
 217     reader::maybe_get_doc(d, tag_item_method_provided_source).map(|doc| {
 218         translated_def_id(cdata, doc)
 219     })
 220 }
 221
 222 fn reexports<'a>(d: rbml::Doc<'a>) -> reader::TaggedDocsIterator<'a> {
 223     reader::tagged_docs(d, tag_items_data_item_reexport)
 224 }
 225
 226 fn variant_disr_val(d: rbml::Doc) -> Option<ty::Disr> {
 227     reader::maybe_get_doc(d, tag_disr_val).and_then(|val_doc| {
 228         reader::with_doc_data(val_doc, |data| {
 229             str::from_utf8(data).ok().and_then(|s| s.parse().ok())
 230         })
 231     })
 232 }
 233
 234 fn doc_type<'tcx>(doc: rbml::Doc, tcx: &ty::ctxt<'tcx>, cdata: Cmd) -> Ty<'tcx> {
 235     let tp = reader::get_doc(doc, tag_items_data_item_type);
 236     parse_ty_data(tp.data, cdata.cnum, tp.start, tcx,
 237                   |_, did| translate_def_id(cdata, did))
 238 }
 239
 240 fn maybe_doc_type<'tcx>(doc: rbml::Doc, tcx: &ty::ctxt<'tcx>, cdata: Cmd) -> Option<Ty<'tcx>> {
 241     reader::maybe_get_doc(doc, tag_items_data_item_type).map(|tp| {
 242         parse_ty_data(tp.data, cdata.cnum, tp.start, tcx,
 243                       |_, did| translate_def_id(cdata, did))
 244     })
 245 }
 246
 247 fn doc_method_fty<'tcx>(doc: rbml::Doc, tcx: &ty::ctxt<'tcx>,
 248                         cdata: Cmd) -> ty::BareFnTy<'tcx> {
 249     let tp = reader::get_doc(doc, tag_item_method_fty);
 250     parse_bare_fn_ty_data(tp.data, cdata.cnum, tp.start, tcx,
 251                           |_, did| translate_def_id(cdata, did))
 252 }
 253
 254 pub fn item_type<'tcx>(_item_id: ast::DefId, item: rbml::Doc,
 255                        tcx: &ty::ctxt<'tcx>, cdata: Cmd) -> Ty<'tcx> {
 256     doc_type(item, tcx, cdata)
 257 }
 258
 259 fn doc_trait_ref<'tcx>(doc: rbml::Doc, tcx: &ty::ctxt<'tcx>, cdata: Cmd)
 260                        -> ty::TraitRef<'tcx> {
 261     parse_trait_ref_data(doc.data, cdata.cnum, doc.start, tcx,
 262                          |_, did| translate_def_id(cdata, did))
 263 }
 264
 265 fn item_trait_ref<'tcx>(doc: rbml::Doc, tcx: &ty::ctxt<'tcx>, cdata: Cmd)
 266                         -> ty::TraitRef<'tcx> {
 267     let tp = reader::get_doc(doc, tag_item_trait_ref);
 268     doc_trait_ref(tp, tcx, cdata)
 269 }
 270
 271 fn item_path(item_doc: rbml::Doc) -> Vec<ast_map::PathElem> {
 272     let path_doc = reader::get_doc(item_doc, tag_path);
 273     reader::docs(path_doc).filter_map(|(tag, elt_doc)| {
 274         if tag == tag_path_elem_mod {
 275             let s = elt_doc.as_str_slice();
 276             Some(ast_map::PathMod(token::intern(s)))
 277         } else if tag == tag_path_elem_name {
 278             let s = elt_doc.as_str_slice();
 279             Some(ast_map::PathName(token::intern(s)))
 280         } else {
 281             // ignore tag_path_len element
 282             None
 283         }
 284     }).collect()
 285 }
 286
 287 fn item_name(intr: &IdentInterner, item: rbml::Doc) -> ast::Name {
 288     let name = reader::get_doc(item, tag_paths_data_name);
 289     let string = name.as_str_slice();
 290     match intr.find(string) {
 291         None => token::intern(string),
 292         Some(val) => val,
 293     }
 294 }
 295
 296 fn item_to_def_like(cdata: Cmd, item: rbml::Doc, did: ast::DefId) -> DefLike {
 297     let fam = item_family(item);
 298     match fam {
 299         Constant  => {
 300             // Check whether we have an associated const item.
 301             if item_sort(item) == Some('C') {
 302                 DlDef(def::DefAssociatedConst(did))
 303             } else {
 304                 // Regular const item.
 305                 DlDef(def::DefConst(did))
 306             }
 307         }
 308         ImmStatic => DlDef(def::DefStatic(did, false)),
 309         MutStatic => DlDef(def::DefStatic(did, true)),
 310         Struct    => DlDef(def::DefStruct(did)),
 311         Fn        => DlDef(def::DefFn(did, false)),
 312         CtorFn    => DlDef(def::DefFn(did, true)),
 313         Method | StaticMethod => {
 314             DlDef(def::DefMethod(did))
 315         }
 316         Type => {
 317             if item_sort(item) == Some('t') {
 318                 let trait_did = item_require_parent_item(cdata, item);
 319                 DlDef(def::DefAssociatedTy(trait_did, did))
 320             } else {
 321                 DlDef(def::DefTy(did, false))
 322             }
 323         }
 324         Mod => DlDef(def::DefMod(did)),
 325         ForeignMod => DlDef(def::DefForeignMod(did)),
 326         StructVariant => {
 327             let enum_did = item_require_parent_item(cdata, item);
 328             DlDef(def::DefVariant(enum_did, did, true))
 329         }
 330         TupleVariant => {
 331             let enum_did = item_require_parent_item(cdata, item);
 332             DlDef(def::DefVariant(enum_did, did, false))
 333         }
 334         Trait => DlDef(def::DefTrait(did)),
 335         Enum => DlDef(def::DefTy(did, true)),
 336         Impl | DefaultImpl => DlImpl(did),
 337         PublicField | InheritedField => DlField,
 338     }
 339 }
 340
 341 fn parse_unsafety(item_doc: rbml::Doc) -> ast::Unsafety {
 342     let unsafety_doc = reader::get_doc(item_doc, tag_unsafety);
 343     if reader::doc_as_u8(unsafety_doc) != 0 {
 344         ast::Unsafety::Unsafe
 345     } else {
 346         ast::Unsafety::Normal
 347     }
 348 }
 349
 350 fn parse_paren_sugar(item_doc: rbml::Doc) -> bool {
 351     let paren_sugar_doc = reader::get_doc(item_doc, tag_paren_sugar);
 352     reader::doc_as_u8(paren_sugar_doc) != 0
 353 }
 354
 355 fn parse_polarity(item_doc: rbml::Doc) -> ast::ImplPolarity {
 356     let polarity_doc = reader::get_doc(item_doc, tag_polarity);
 357     if reader::doc_as_u8(polarity_doc) != 0 {
 358         ast::ImplPolarity::Negative
 359     } else {
 360         ast::ImplPolarity::Positive
 361     }
 362 }
 363
 364 fn parse_associated_type_names(item_doc: rbml::Doc) -> Vec<ast::Name> {
 365     let names_doc = reader::get_doc(item_doc, tag_associated_type_names);
 366     reader::tagged_docs(names_doc, tag_associated_type_name)
 367         .map(|name_doc| token::intern(name_doc.as_str_slice()))
 368         .collect()
 369 }
 370
 371 pub fn get_trait_def<'tcx>(cdata: Cmd,
 372                            item_id: ast::NodeId,
 373                            tcx: &ty::ctxt<'tcx>) -> ty::TraitDef<'tcx>
 374 {
 375     let item_doc = lookup_item(item_id, cdata.data());
 376     let generics = doc_generics(item_doc, tcx, cdata, tag_item_generics);
 377     let unsafety = parse_unsafety(item_doc);
 378     let associated_type_names = parse_associated_type_names(item_doc);
 379     let paren_sugar = parse_paren_sugar(item_doc);
 380
 381     ty::TraitDef {
 382         paren_sugar: paren_sugar,
 383         unsafety: unsafety,
 384         generics: generics,
 385         trait_ref: item_trait_ref(item_doc, tcx, cdata),
 386         associated_type_names: associated_type_names,
 387         nonblanket_impls: RefCell::new(FnvHashMap()),
 388         blanket_impls: RefCell::new(vec![]),
 389         flags: Cell::new(ty::TraitFlags::NO_TRAIT_FLAGS)
 390     }
 391 }
 392
 393 pub fn get_predicates<'tcx>(cdata: Cmd,
 394                             item_id: ast::NodeId,
 395                             tcx: &ty::ctxt<'tcx>)
 396                             -> ty::GenericPredicates<'tcx>
 397 {
 398     let item_doc = lookup_item(item_id, cdata.data());
 399     doc_predicates(item_doc, tcx, cdata, tag_item_generics)
 400 }
 401
 402 pub fn get_super_predicates<'tcx>(cdata: Cmd,
 403                                   item_id: ast::NodeId,
 404                                   tcx: &ty::ctxt<'tcx>)
 405                                   -> ty::GenericPredicates<'tcx>
 406 {
 407     let item_doc = lookup_item(item_id, cdata.data());
 408     doc_predicates(item_doc, tcx, cdata, tag_item_super_predicates)
 409 }
 410
 411 pub fn get_type<'tcx>(cdata: Cmd, id: ast::NodeId, tcx: &ty::ctxt<'tcx>)
 412                       -> ty::TypeScheme<'tcx>
 413 {
 414     let item_doc = lookup_item(id, cdata.data());
 415     let t = item_type(ast::DefId { krate: cdata.cnum, node: id }, item_doc, tcx,
 416                       cdata);
 417     let generics = doc_generics(item_doc, tcx, cdata, tag_item_generics);
 418     ty::TypeScheme {
 419         generics: generics,
 420         ty: t
 421     }
 422 }
 423
 424 pub fn get_stability(cdata: Cmd, id: ast::NodeId) -> Option<attr::Stability> {
 425     let item = lookup_item(id, cdata.data());
 426     reader::maybe_get_doc(item, tag_items_data_item_stability).map(|doc| {
 427         let mut decoder = reader::Decoder::new(doc);
 428         Decodable::decode(&mut decoder).unwrap()
 429     })
 430 }
 431
 432 pub fn get_repr_attrs(cdata: Cmd, id: ast::NodeId) -> Vec<attr::ReprAttr> {
 433     let item = lookup_item(id, cdata.data());
 434     match reader::maybe_get_doc(item, tag_items_data_item_repr).map(|doc| {
 435         let mut decoder = reader::Decoder::new(doc);
 436         Decodable::decode(&mut decoder).unwrap()
 437     }) {
 438         Some(attrs) => attrs,
 439         None => Vec::new(),
 440     }
 441 }
 442
 443 pub fn get_impl_polarity<'tcx>(cdata: Cmd,
 444                                id: ast::NodeId)
 445                                -> Option<ast::ImplPolarity>
 446 {
 447     let item_doc = lookup_item(id, cdata.data());
 448     let fam = item_family(item_doc);
 449     match fam {
 450         Family::Impl => {
 451             Some(parse_polarity(item_doc))
 452         }
 453         _ => None
 454     }
 455 }
 456
 457 pub fn get_custom_coerce_unsized_kind<'tcx>(cdata: Cmd,
 458                                             id: ast::NodeId)
 459                                             -> Option<ty::CustomCoerceUnsized> {
 460     let item_doc = lookup_item(id, cdata.data());
 461     reader::maybe_get_doc(item_doc, tag_impl_coerce_unsized_kind).map(|kind_doc| {
 462         let mut decoder = reader::Decoder::new(kind_doc);
 463         Decodable::decode(&mut decoder).unwrap()
 464     })
 465 }
 466
 467 pub fn get_impl_trait<'tcx>(cdata: Cmd,
 468                             id: ast::NodeId,
 469                             tcx: &ty::ctxt<'tcx>)
 470                             -> Option<ty::TraitRef<'tcx>>
 471 {
 472     let item_doc = lookup_item(id, cdata.data());
 473     let fam = item_family(item_doc);
 474     match fam {
 475         Family::Impl | Family::DefaultImpl => {
 476             reader::maybe_get_doc(item_doc, tag_item_trait_ref).map(|tp| {
 477                 doc_trait_ref(tp, tcx, cdata)
 478             })
 479         }
 480         _ => None
 481     }
 482 }
 483
 484 pub fn get_symbol(data: &[u8], id: ast::NodeId) -> String {
 485     return item_symbol(lookup_item(id, data));
 486 }
 487
 488 // Something that a name can resolve to.
 489 #[derive(Copy, Clone, Debug)]
 490 pub enum DefLike {
 491     DlDef(def::Def),
 492     DlImpl(ast::DefId),
 493     DlField
 494 }
 495
 496 /// Iterates over the language items in the given crate.
 497 pub fn each_lang_item<F>(cdata: Cmd, mut f: F) -> bool where
 498     F: FnMut(ast::NodeId, usize) -> bool,
 499 {
 500     let root = rbml::Doc::new(cdata.data());
 501     let lang_items = reader::get_doc(root, tag_lang_items);
 502     reader::tagged_docs(lang_items, tag_lang_items_item).all(|item_doc| {
 503         let id_doc = reader::get_doc(item_doc, tag_lang_items_item_id);
 504         let id = reader::doc_as_u32(id_doc) as usize;
 505         let node_id_doc = reader::get_doc(item_doc,
 506                                           tag_lang_items_item_node_id);
 507         let node_id = reader::doc_as_u32(node_id_doc) as ast::NodeId;
 508
 509         f(node_id, id)
 510     })
 511 }
 512
 513 fn each_child_of_item_or_crate<F, G>(intr: Rc<IdentInterner>,
 514                                      cdata: Cmd,
 515                                      item_doc: rbml::Doc,
 516                                      mut get_crate_data: G,
 517                                      mut callback: F) where
 518     F: FnMut(DefLike, ast::Name, ast::Visibility),
 519     G: FnMut(ast::CrateNum) -> Rc<crate_metadata>,
 520 {
 521     // Iterate over all children.
 522     for child_info_doc in reader::tagged_docs(item_doc, tag_mod_child) {
 523         let child_def_id = translated_def_id(cdata, child_info_doc);
 524
 525         // This item may be in yet another crate if it was the child of a
 526         // reexport.
 527         let crate_data = if child_def_id.krate == cdata.cnum {
 528             None
 529         } else {
 530             Some(get_crate_data(child_def_id.krate))
 531         };
 532         let crate_data = match crate_data {
 533             Some(ref cdata) => &**cdata,
 534             None => cdata
 535         };
 536
 537         let other_crates_items = reader::get_doc(rbml::Doc::new(crate_data.data()), tag_items);
 538
 539         // Get the item.
 540         match maybe_find_item(child_def_id.node, other_crates_items) {
 541             None => {}
 542             Some(child_item_doc) => {
 543                 // Hand off the item to the callback.
 544                 let child_name = item_name(&*intr, child_item_doc);
 545                 let def_like = item_to_def_like(crate_data, child_item_doc, child_def_id);
 546                 let visibility = item_visibility(child_item_doc);
 547                 callback(def_like, child_name, visibility);
 548             }
 549         }
 550     }
 551
 552     // As a special case, iterate over all static methods of
 553     // associated implementations too. This is a bit of a botch.
 554     // --pcwalton
 555     for inherent_impl_def_id_doc in reader::tagged_docs(item_doc,
 556                                                              tag_items_data_item_inherent_impl) {
 557         let inherent_impl_def_id = item_def_id(inherent_impl_def_id_doc, cdata);
 558         let items = reader::get_doc(rbml::Doc::new(cdata.data()), tag_items);
 559         if let Some(inherent_impl_doc) = maybe_find_item(inherent_impl_def_id.node, items) {
 560             for impl_item_def_id_doc in reader::tagged_docs(inherent_impl_doc,
 561                                                                  tag_item_impl_item) {
 562                 let impl_item_def_id = item_def_id(impl_item_def_id_doc,
 563                                                    cdata);
 564                 if let Some(impl_method_doc) = maybe_find_item(impl_item_def_id.node, items) {
 565                     if let StaticMethod = item_family(impl_method_doc) {
 566                         // Hand off the static method to the callback.
 567                         let static_method_name = item_name(&*intr, impl_method_doc);
 568                         let static_method_def_like = item_to_def_like(cdata, impl_method_doc,
 569                                                                       impl_item_def_id);
 570                         callback(static_method_def_like,
 571                                  static_method_name,
 572                                  item_visibility(impl_method_doc));
 573                     }
 574                 }
 575             }
 576         }
 577     }
 578
 579     for reexport_doc in reexports(item_doc) {
 580         let def_id_doc = reader::get_doc(reexport_doc,
 581                                          tag_items_data_item_reexport_def_id);
 582         let child_def_id = translated_def_id(cdata, def_id_doc);
 583
 584         let name_doc = reader::get_doc(reexport_doc,
 585                                        tag_items_data_item_reexport_name);
 586         let name = name_doc.as_str_slice();
 587
 588         // This reexport may be in yet another crate.
 589         let crate_data = if child_def_id.krate == cdata.cnum {
 590             None
 591         } else {
 592             Some(get_crate_data(child_def_id.krate))
 593         };
 594         let crate_data = match crate_data {
 595             Some(ref cdata) => &**cdata,
 596             None => cdata
 597         };
 598
 599         let other_crates_items = reader::get_doc(rbml::Doc::new(crate_data.data()), tag_items);
 600
 601         // Get the item.
 602         if let Some(child_item_doc) = maybe_find_item(child_def_id.node, other_crates_items) {
 603             // Hand off the item to the callback.
 604             let def_like = item_to_def_like(crate_data, child_item_doc, child_def_id);
 605             // These items have a public visibility because they're part of
 606             // a public re-export.
 607             callback(def_like, token::intern(name), ast::Public);
 608         }
 609     }
 610 }
 611
 612 /// Iterates over each child of the given item.
 613 pub fn each_child_of_item<F, G>(intr: Rc<IdentInterner>,
 614                                cdata: Cmd,
 615                                id: ast::NodeId,
 616                                get_crate_data: G,
 617                                callback: F) where
 618     F: FnMut(DefLike, ast::Name, ast::Visibility),
 619     G: FnMut(ast::CrateNum) -> Rc<crate_metadata>,
 620 {
 621     // Find the item.
 622     let root_doc = rbml::Doc::new(cdata.data());
 623     let items = reader::get_doc(root_doc, tag_items);
 624     let item_doc = match maybe_find_item(id, items) {
 625         None => return,
 626         Some(item_doc) => item_doc,
 627     };
 628
 629     each_child_of_item_or_crate(intr,
 630                                 cdata,
 631                                 item_doc,
 632                                 get_crate_data,
 633                                 callback)
 634 }
 635
 636 /// Iterates over all the top-level crate items.
 637 pub fn each_top_level_item_of_crate<F, G>(intr: Rc<IdentInterner>,
 638                                           cdata: Cmd,
 639                                           get_crate_data: G,
 640                                           callback: F) where
 641     F: FnMut(DefLike, ast::Name, ast::Visibility),
 642     G: FnMut(ast::CrateNum) -> Rc<crate_metadata>,
 643 {
 644     let root_doc = rbml::Doc::new(cdata.data());
 645     let misc_info_doc = reader::get_doc(root_doc, tag_misc_info);
 646     let crate_items_doc = reader::get_doc(misc_info_doc,
 647                                           tag_misc_info_crate_items);
 648
 649     each_child_of_item_or_crate(intr,
 650                                 cdata,
 651                                 crate_items_doc,
 652                                 get_crate_data,
 653                                 callback)
 654 }
 655
 656 pub fn get_item_path(cdata: Cmd, id: ast::NodeId) -> Vec<ast_map::PathElem> {
 657     item_path(lookup_item(id, cdata.data()))
 658 }
 659
 660 pub type DecodeInlinedItem<'a> =
 661     Box<for<'tcx> FnMut(Cmd,
 662                         &ty::ctxt<'tcx>,
 663                         Vec<ast_map::PathElem>,
 664                         rbml::Doc)
 665                         -> Result<&'tcx ast::InlinedItem, Vec<ast_map::PathElem>> + 'a>;
 666
 667 pub fn maybe_get_item_ast<'tcx>(cdata: Cmd, tcx: &ty::ctxt<'tcx>, id: ast::NodeId,
 668                                 mut decode_inlined_item: DecodeInlinedItem)
 669                                 -> csearch::FoundAst<'tcx> {
 670     debug!("Looking up item: {}", id);
 671     let item_doc = lookup_item(id, cdata.data());
 672     let path = item_path(item_doc).split_last().unwrap().1.to_vec();
 673     match decode_inlined_item(cdata, tcx, path, item_doc) {
 674         Ok(ii) => csearch::FoundAst::Found(ii),
 675         Err(path) => {
 676             match item_parent_item(cdata, item_doc) {
 677                 Some(did) => {
 678                     let parent_item = lookup_item(did.node, cdata.data());
 679                     match decode_inlined_item(cdata, tcx, path, parent_item) {
 680                         Ok(ii) => csearch::FoundAst::FoundParent(did, ii),
 681                         Err(_) => csearch::FoundAst::NotFound
 682                     }
 683                 }
 684                 None => csearch::FoundAst::NotFound
 685             }
 686         }
 687     }
 688 }
 689
 690 pub fn get_enum_variants<'tcx>(intr: Rc<IdentInterner>, cdata: Cmd, id: ast::NodeId,
 691                                tcx: &ty::ctxt<'tcx>) -> Vec<Rc<ty::VariantInfo<'tcx>>> {
 692     let data = cdata.data();
 693     let items = reader::get_doc(rbml::Doc::new(data), tag_items);
 694     let item = find_item(id, items);
 695     let mut disr_val = 0;
 696     reader::tagged_docs(item, tag_items_data_item_variant).map(|p| {
 697         let did = translated_def_id(cdata, p);
 698         let item = find_item(did.node, items);
 699         let ctor_ty = item_type(ast::DefId { krate: cdata.cnum, node: id},
 700                                 item, tcx, cdata);
 701         let name = item_name(&*intr, item);
 702         let (ctor_ty, arg_tys, arg_names) = match ctor_ty.sty {
 703             ty::TyBareFn(_, ref f) =>
 704                 (Some(ctor_ty), f.sig.0.inputs.clone(), None),
 705             _ => { // Nullary or struct enum variant.
 706                 let mut arg_names = Vec::new();
 707                 let arg_tys = get_struct_fields(intr.clone(), cdata, did.node)
 708                     .iter()
 709                     .map(|field_ty| {
 710                         arg_names.push(field_ty.name);
 711                         get_type(cdata, field_ty.id.node, tcx).ty
 712                     })
 713                     .collect();
 714                 let arg_names = if arg_names.is_empty() { None } else { Some(arg_names) };
 715
 716                 (None, arg_tys, arg_names)
 717             }
 718         };
 719         match variant_disr_val(item) {
 720             Some(val) => { disr_val = val; }
 721             _         => { /* empty */ }
 722         }
 723         let old_disr_val = disr_val;
 724         disr_val = disr_val.wrapping_add(1);
 725         Rc::new(ty::VariantInfo {
 726             args: arg_tys,
 727             arg_names: arg_names,
 728             ctor_ty: ctor_ty,
 729             name: name,
 730             // I'm not even sure if we encode visibility
 731             // for variants -- TEST -- tjc
 732             id: did,
 733             disr_val: old_disr_val,
 734             vis: ast::Inherited
 735         })
 736     }).collect()
 737 }
 738
 739 fn get_explicit_self(item: rbml::Doc) -> ty::ExplicitSelfCategory {
 740     fn get_mutability(ch: u8) -> ast::Mutability {
 741         match ch as char {
 742             'i' => ast::MutImmutable,
 743             'm' => ast::MutMutable,
 744             _ => panic!("unknown mutability character: `{}`", ch as char),
 745         }
 746     }
 747
 748     let explicit_self_doc = reader::get_doc(item, tag_item_trait_method_explicit_self);
 749     let string = explicit_self_doc.as_str_slice();
 750
 751     let explicit_self_kind = string.as_bytes()[0];
 752     match explicit_self_kind as char {
 753         's' => ty::StaticExplicitSelfCategory,
 754         'v' => ty::ByValueExplicitSelfCategory,
 755         '~' => ty::ByBoxExplicitSelfCategory,
 756         // FIXME(#4846) expl. region
 757         '&' => {
 758             ty::ByReferenceExplicitSelfCategory(
 759                 ty::ReEmpty,
 760                 get_mutability(string.as_bytes()[1]))
 761         }
 762         _ => panic!("unknown self type code: `{}`", explicit_self_kind as char)
 763     }
 764 }
 765
 766 /// Returns the def IDs of all the items in the given implementation.
 767 pub fn get_impl_items(cdata: Cmd, impl_id: ast::NodeId)
 768                       -> Vec<ty::ImplOrTraitItemId> {
 769     reader::tagged_docs(lookup_item(impl_id, cdata.data()), tag_item_impl_item).map(|doc| {
 770         let def_id = item_def_id(doc, cdata);
 771         match item_sort(doc) {
 772             Some('C') => ty::ConstTraitItemId(def_id),
 773             Some('r') | Some('p') => ty::MethodTraitItemId(def_id),
 774             Some('t') => ty::TypeTraitItemId(def_id),
 775             _ => panic!("unknown impl item sort"),
 776         }
 777     }).collect()
 778 }
 779
 780 pub fn get_trait_name(intr: Rc<IdentInterner>,
 781                       cdata: Cmd,
 782                       id: ast::NodeId)
 783                       -> ast::Name {
 784     let doc = lookup_item(id, cdata.data());
 785     item_name(&*intr, doc)
 786 }
 787
 788 pub fn is_static_method(cdata: Cmd, id: ast::NodeId) -> bool {
 789     let doc = lookup_item(id, cdata.data());
 790     match item_sort(doc) {
 791         Some('r') | Some('p') => {
 792             get_explicit_self(doc) == ty::StaticExplicitSelfCategory
 793         }
 794         _ => false
 795     }
 796 }
 797
 798 pub fn get_impl_or_trait_item<'tcx>(intr: Rc<IdentInterner>,
 799                                     cdata: Cmd,
 800                                     id: ast::NodeId,
 801                                     tcx: &ty::ctxt<'tcx>)
 802                                     -> ty::ImplOrTraitItem<'tcx> {
 803     let item_doc = lookup_item(id, cdata.data());
 804
 805     let def_id = item_def_id(item_doc, cdata);
 806
 807     let container_id = item_require_parent_item(cdata, item_doc);
 808     let container_doc = lookup_item(container_id.node, cdata.data());
 809     let container = match item_family(container_doc) {
 810         Trait => TraitContainer(container_id),
 811         _ => ImplContainer(container_id),
 812     };
 813
 814     let name = item_name(&*intr, item_doc);
 815     let vis = item_visibility(item_doc);
 816
 817     match item_sort(item_doc) {
 818         Some('C') => {
 819             let ty = doc_type(item_doc, tcx, cdata);
 820             let default = get_provided_source(item_doc, cdata);
 821             ty::ConstTraitItem(Rc::new(ty::AssociatedConst {
 822                 name: name,
 823                 ty: ty,
 824                 vis: vis,
 825                 def_id: def_id,
 826                 container: container,
 827                 default: default,
 828             }))
 829         }
 830         Some('r') | Some('p') => {
 831             let generics = doc_generics(item_doc, tcx, cdata, tag_method_ty_generics);
 832             let predicates = doc_predicates(item_doc, tcx, cdata, tag_method_ty_generics);
 833             let fty = doc_method_fty(item_doc, tcx, cdata);
 834             let explicit_self = get_explicit_self(item_doc);
 835             let provided_source = get_provided_source(item_doc, cdata);
 836
 837             ty::MethodTraitItem(Rc::new(ty::Method::new(name,
 838                                                         generics,
 839                                                         predicates,
 840                                                         fty,
 841                                                         explicit_self,
 842                                                         vis,
 843                                                         def_id,
 844                                                         container,
 845                                                         provided_source)))
 846         }
 847         Some('t') => {
 848             let ty = maybe_doc_type(item_doc, tcx, cdata);
 849             ty::TypeTraitItem(Rc::new(ty::AssociatedType {
 850                 name: name,
 851                 ty: ty,
 852                 vis: vis,
 853                 def_id: def_id,
 854                 container: container,
 855             }))
 856         }
 857         _ => panic!("unknown impl/trait item sort"),
 858     }
 859 }
 860
 861 pub fn get_trait_item_def_ids(cdata: Cmd, id: ast::NodeId)
 862                               -> Vec<ty::ImplOrTraitItemId> {
 863     let data = cdata.data();
 864     let item = lookup_item(id, data);
 865     reader::tagged_docs(item, tag_item_trait_item).map(|mth| {
 866         let def_id = item_def_id(mth, cdata);
 867         match item_sort(mth) {
 868             Some('C') => ty::ConstTraitItemId(def_id),
 869             Some('r') | Some('p') => ty::MethodTraitItemId(def_id),
 870             Some('t') => ty::TypeTraitItemId(def_id),
 871             _ => panic!("unknown trait item sort"),
 872         }
 873     }).collect()
 874 }
 875
 876 pub fn get_item_variances(cdata: Cmd, id: ast::NodeId) -> ty::ItemVariances {
 877     let data = cdata.data();
 878     let item_doc = lookup_item(id, data);
 879     let variance_doc = reader::get_doc(item_doc, tag_item_variances);
 880     let mut decoder = reader::Decoder::new(variance_doc);
 881     Decodable::decode(&mut decoder).unwrap()
 882 }
 883
 884 pub fn get_provided_trait_methods<'tcx>(intr: Rc<IdentInterner>,
 885                                         cdata: Cmd,
 886                                         id: ast::NodeId,
 887                                         tcx: &ty::ctxt<'tcx>)
 888                                         -> Vec<Rc<ty::Method<'tcx>>> {
 889     let data = cdata.data();
 890     let item = lookup_item(id, data);
 891
 892     reader::tagged_docs(item, tag_item_trait_item).filter_map(|mth_id| {
 893         let did = item_def_id(mth_id, cdata);
 894         let mth = lookup_item(did.node, data);
 895
 896         if item_sort(mth) == Some('p') {
 897             let trait_item = get_impl_or_trait_item(intr.clone(),
 898                                                     cdata,
 899                                                     did.node,
 900                                                     tcx);
 901             if let ty::MethodTraitItem(ref method) = trait_item {
 902                 Some((*method).clone())
 903             } else {
 904                 None
 905             }
 906         } else {
 907             None
 908         }
 909     }).collect()
 910 }
 911
 912 pub fn get_associated_consts<'tcx>(intr: Rc<IdentInterner>,
 913                                    cdata: Cmd,
 914                                    id: ast::NodeId,
 915                                    tcx: &ty::ctxt<'tcx>)
 916                                    -> Vec<Rc<ty::AssociatedConst<'tcx>>> {
 917     let data = cdata.data();
 918     let item = lookup_item(id, data);
 919
 920     [tag_item_trait_item, tag_item_impl_item].iter().flat_map(|&tag| {
 921         reader::tagged_docs(item, tag).filter_map(|ac_id| {
 922             let did = item_def_id(ac_id, cdata);
 923             let ac_doc = lookup_item(did.node, data);
 924
 925             if item_sort(ac_doc) == Some('C') {
 926                 let trait_item = get_impl_or_trait_item(intr.clone(),
 927                                                         cdata,
 928                                                         did.node,
 929                                                         tcx);
 930                 if let ty::ConstTraitItem(ref ac) = trait_item {
 931                     Some((*ac).clone())
 932                 } else {
 933                     None
 934                 }
 935             } else {
 936                 None
 937             }
 938         })
 939     }).collect()
 940 }
 941
 942 pub fn get_type_name_if_impl(cdata: Cmd,
 943                              node_id: ast::NodeId) -> Option<ast::Name> {
 944     let item = lookup_item(node_id, cdata.data());
 945     if item_family(item) != Impl {
 946         return None;
 947     }
 948
 949     reader::tagged_docs(item, tag_item_impl_type_basename).nth(0).map(|doc| {
 950         token::intern(doc.as_str_slice())
 951     })
 952 }
 953
 954 pub fn get_methods_if_impl(intr: Rc<IdentInterner>,
 955                                   cdata: Cmd,
 956                                   node_id: ast::NodeId)
 957                                -> Option<Vec<MethodInfo> > {
 958     let item = lookup_item(node_id, cdata.data());
 959     if item_family(item) != Impl {
 960         return None;
 961     }
 962
 963     // If this impl implements a trait, don't consider it.
 964     if reader::tagged_docs(item, tag_item_trait_ref).next().is_some() {
 965         return None;
 966     }
 967
 968     let impl_method_ids = reader::tagged_docs(item, tag_item_impl_item)
 969         .map(|impl_method_doc| item_def_id(impl_method_doc, cdata));
 970
 971     let mut impl_methods = Vec::new();
 972     for impl_method_id in impl_method_ids {
 973         let impl_method_doc = lookup_item(impl_method_id.node, cdata.data());
 974         let family = item_family(impl_method_doc);
 975         match family {
 976             StaticMethod | Method => {
 977                 impl_methods.push(MethodInfo {
 978                     name: item_name(&*intr, impl_method_doc),
 979                     def_id: item_def_id(impl_method_doc, cdata),
 980                     vis: item_visibility(impl_method_doc),
 981                 });
 982             }
 983             _ => {}
 984         }
 985     }
 986
 987     return Some(impl_methods);
 988 }
 989
 990 /// If node_id is the constructor of a tuple struct, retrieve the NodeId of
 991 /// the actual type definition, otherwise, return None
 992 pub fn get_tuple_struct_definition_if_ctor(cdata: Cmd,
 993                                            node_id: ast::NodeId)
 994     -> Option<ast::DefId>
 995 {
 996     let item = lookup_item(node_id, cdata.data());
 997     reader::tagged_docs(item, tag_items_data_item_is_tuple_struct_ctor).next().map(|_| {
 998         item_require_parent_item(cdata, item)
 999     })
1000 }
1001
1002 pub fn get_item_attrs(cdata: Cmd,
1003                       orig_node_id: ast::NodeId)
1004                       -> Vec<ast::Attribute> {
1005     // The attributes for a tuple struct are attached to the definition, not the ctor;
1006     // we assume that someone passing in a tuple struct ctor is actually wanting to
1007     // look at the definition
1008     let node_id = get_tuple_struct_definition_if_ctor(cdata, orig_node_id);
1009     let node_id = node_id.map(|x| x.node).unwrap_or(orig_node_id);
1010     let item = lookup_item(node_id, cdata.data());
1011     get_attributes(item)
1012 }
1013
1014 pub fn get_struct_field_attrs(cdata: Cmd) -> HashMap<ast::NodeId, Vec<ast::Attribute>> {
1015     let data = rbml::Doc::new(cdata.data());
1016     let fields = reader::get_doc(data, tag_struct_fields);
1017     reader::tagged_docs(fields, tag_struct_field).map(|field| {
1018         let id = reader::doc_as_u32(reader::get_doc(field, tag_struct_field_id));
1019         let attrs = get_attributes(field);
1020         (id, attrs)
1021     }).collect()
1022 }
1023
1024 fn struct_field_family_to_visibility(family: Family) -> ast::Visibility {
1025     match family {
1026       PublicField => ast::Public,
1027       InheritedField => ast::Inherited,
1028       _ => panic!()
1029     }
1030 }
1031
1032 pub fn get_struct_fields(intr: Rc<IdentInterner>, cdata: Cmd, id: ast::NodeId)
1033     -> Vec<ty::FieldTy> {
1034     let data = cdata.data();
1035     let item = lookup_item(id, data);
1036     reader::tagged_docs(item, tag_item_field).filter_map(|an_item| {
1037         let f = item_family(an_item);
1038         if f == PublicField || f == InheritedField {
1039             let name = item_name(&*intr, an_item);
1040             let did = item_def_id(an_item, cdata);
1041             let tagdoc = reader::get_doc(an_item, tag_item_field_origin);
1042             let origin_id =  translated_def_id(cdata, tagdoc);
1043             Some(ty::FieldTy {
1044                 name: name,
1045                 id: did,
1046                 vis: struct_field_family_to_visibility(f),
1047                 origin: origin_id,
1048             })
1049         } else {
1050             None
1051         }
1052     }).chain(reader::tagged_docs(item, tag_item_unnamed_field).map(|an_item| {
1053         let did = item_def_id(an_item, cdata);
1054         let tagdoc = reader::get_doc(an_item, tag_item_field_origin);
1055         let f = item_family(an_item);
1056         let origin_id =  translated_def_id(cdata, tagdoc);
1057         ty::FieldTy {
1058             name: special_idents::unnamed_field.name,
1059             id: did,
1060             vis: struct_field_family_to_visibility(f),
1061             origin: origin_id,
1062         }
1063     })).collect()
1064 }
1065
1066 fn get_meta_items(md: rbml::Doc) -> Vec<P<ast::MetaItem>> {
1067     reader::tagged_docs(md, tag_meta_item_word).map(|meta_item_doc| {
1068         let nd = reader::get_doc(meta_item_doc, tag_meta_item_name);
1069         let n = token::intern_and_get_ident(nd.as_str_slice());
1070         attr::mk_word_item(n)
1071     }).chain(reader::tagged_docs(md, tag_meta_item_name_value).map(|meta_item_doc| {
1072         let nd = reader::get_doc(meta_item_doc, tag_meta_item_name);
1073         let vd = reader::get_doc(meta_item_doc, tag_meta_item_value);
1074         let n = token::intern_and_get_ident(nd.as_str_slice());
1075         let v = token::intern_and_get_ident(vd.as_str_slice());
1076         // FIXME (#623): Should be able to decode MetaNameValue variants,
1077         // but currently the encoder just drops them
1078         attr::mk_name_value_item_str(n, v)
1079     })).chain(reader::tagged_docs(md, tag_meta_item_list).map(|meta_item_doc| {
1080         let nd = reader::get_doc(meta_item_doc, tag_meta_item_name);
1081         let n = token::intern_and_get_ident(nd.as_str_slice());
1082         let subitems = get_meta_items(meta_item_doc);
1083         attr::mk_list_item(n, subitems)
1084     })).collect()
1085 }
1086
1087 fn get_attributes(md: rbml::Doc) -> Vec<ast::Attribute> {
1088     match reader::maybe_get_doc(md, tag_attributes) {
1089         Some(attrs_d) => {
1090             reader::tagged_docs(attrs_d, tag_attribute).map(|attr_doc| {
1091                 let is_sugared_doc = reader::doc_as_u8(
1092                     reader::get_doc(attr_doc, tag_attribute_is_sugared_doc)
1093                 ) == 1;
1094                 let meta_items = get_meta_items(attr_doc);
1095                 // Currently it's only possible to have a single meta item on
1096                 // an attribute
1097                 assert_eq!(meta_items.len(), 1);
1098                 let meta_item = meta_items.into_iter().nth(0).unwrap();
1099                 codemap::Spanned {
1100                     node: ast::Attribute_ {
1101                         id: attr::mk_attr_id(),
1102                         style: ast::AttrOuter,
1103                         value: meta_item,
1104                         is_sugared_doc: is_sugared_doc,
1105                     },
1106                     span: codemap::DUMMY_SP
1107                 }
1108             }).collect()
1109         },
1110         None => vec![],
1111     }
1112 }
1113
1114 fn list_crate_attributes(md: rbml::Doc, hash: &Svh,
1115                          out: &mut io::Write) -> io::Result<()> {
1116     try!(write!(out, "=Crate Attributes ({})=\n", *hash));
1117
1118     let r = get_attributes(md);
1119     for attr in &r {
1120         try!(write!(out, "{}\n", pprust::attribute_to_string(attr)));
1121     }
1122
1123     write!(out, "\n\n")
1124 }
1125
1126 pub fn get_crate_attributes(data: &[u8]) -> Vec<ast::Attribute> {
1127     get_attributes(rbml::Doc::new(data))
1128 }
1129
1130 #[derive(Clone)]
1131 pub struct CrateDep {
1132     pub cnum: ast::CrateNum,
1133     pub name: String,
1134     pub hash: Svh,
1135 }
1136
1137 pub fn get_crate_deps(data: &[u8]) -> Vec<CrateDep> {
1138     let cratedoc = rbml::Doc::new(data);
1139     let depsdoc = reader::get_doc(cratedoc, tag_crate_deps);
1140
1141     fn docstr(doc: rbml::Doc, tag_: usize) -> String {
1142         let d = reader::get_doc(doc, tag_);
1143         d.as_str_slice().to_string()
1144     }
1145
1146     reader::tagged_docs(depsdoc, tag_crate_dep).enumerate().map(|(crate_num, depdoc)| {
1147         let name = docstr(depdoc, tag_crate_dep_crate_name);
1148         let hash = Svh::new(&docstr(depdoc, tag_crate_dep_hash));
1149         CrateDep {
1150             cnum: crate_num as u32 + 1,
1151             name: name,
1152             hash: hash,
1153         }
1154     }).collect()
1155 }
1156
1157 fn list_crate_deps(data: &[u8], out: &mut io::Write) -> io::Result<()> {
1158     try!(write!(out, "=External Dependencies=\n"));
1159     for dep in &get_crate_deps(data) {
1160         try!(write!(out, "{} {}-{}\n", dep.cnum, dep.name, dep.hash));
1161     }
1162     try!(write!(out, "\n"));
1163     Ok(())
1164 }
1165
1166 pub fn maybe_get_crate_hash(data: &[u8]) -> Option<Svh> {
1167     let cratedoc = rbml::Doc::new(data);
1168     reader::maybe_get_doc(cratedoc, tag_crate_hash).map(|doc| {
1169         Svh::new(doc.as_str_slice())
1170     })
1171 }
1172
1173 pub fn get_crate_hash(data: &[u8]) -> Svh {
1174     let cratedoc = rbml::Doc::new(data);
1175     let hashdoc = reader::get_doc(cratedoc, tag_crate_hash);
1176     Svh::new(hashdoc.as_str_slice())
1177 }
1178
1179 pub fn maybe_get_crate_name(data: &[u8]) -> Option<String> {
1180     let cratedoc = rbml::Doc::new(data);
1181     reader::maybe_get_doc(cratedoc, tag_crate_crate_name).map(|doc| {
1182         doc.as_str_slice().to_string()
1183     })
1184 }
1185
1186 pub fn get_crate_triple(data: &[u8]) -> Option<String> {
1187     let cratedoc = rbml::Doc::new(data);
1188     let triple_doc = reader::maybe_get_doc(cratedoc, tag_crate_triple);
1189     triple_doc.map(|s| s.as_str().to_string())
1190 }
1191
1192 pub fn get_crate_name(data: &[u8]) -> String {
1193     maybe_get_crate_name(data).expect("no crate name in crate")
1194 }
1195
1196 pub fn list_crate_metadata(bytes: &[u8], out: &mut io::Write) -> io::Result<()> {
1197     let hash = get_crate_hash(bytes);
1198     let md = rbml::Doc::new(bytes);
1199     try!(list_crate_attributes(md, &hash, out));
1200     list_crate_deps(bytes, out)
1201 }
1202
1203 // Translates a def_id from an external crate to a def_id for the current
1204 // compilation environment. We use this when trying to load types from
1205 // external crates - if those types further refer to types in other crates
1206 // then we must translate the crate number from that encoded in the external
1207 // crate to the correct local crate number.
1208 pub fn translate_def_id(cdata: Cmd, did: ast::DefId) -> ast::DefId {
1209     if did.krate == ast::LOCAL_CRATE {
1210         return ast::DefId { krate: cdata.cnum, node: did.node };
1211     }
1212
1213     match cdata.cnum_map.get(&did.krate) {
1214         Some(&n) => {
1215             ast::DefId {
1216                 krate: n,
1217                 node: did.node,
1218             }
1219         }
1220         None => panic!("didn't find a crate in the cnum_map")
1221     }
1222 }
1223
1224 // Translate a DefId from the current compilation environment to a DefId
1225 // for an external crate.
1226 fn reverse_translate_def_id(cdata: Cmd, did: ast::DefId) -> Option<ast::DefId> {
1227     if did.krate == cdata.cnum {
1228         return Some(ast::DefId { krate: ast::LOCAL_CRATE, node: did.node });
1229     }
1230
1231     for (&local, &global) in &cdata.cnum_map {
1232         if global == did.krate {
1233             return Some(ast::DefId { krate: local, node: did.node });
1234         }
1235     }
1236
1237     None
1238 }
1239
1240 pub fn each_inherent_implementation_for_type<F>(cdata: Cmd,
1241                                                 id: ast::NodeId,
1242                                                 mut callback: F)
1243     where F: FnMut(ast::DefId),
1244 {
1245     let item_doc = lookup_item(id, cdata.data());
1246     for impl_doc in reader::tagged_docs(item_doc, tag_items_data_item_inherent_impl) {
1247         if reader::maybe_get_doc(impl_doc, tag_item_trait_ref).is_none() {
1248             callback(item_def_id(impl_doc, cdata));
1249         }
1250     }
1251 }
1252
1253 pub fn each_implementation_for_trait<F>(cdata: Cmd,
1254                                         def_id: ast::DefId,
1255                                         mut callback: F) where
1256     F: FnMut(ast::DefId),
1257 {
1258     if cdata.cnum == def_id.krate {
1259         let item_doc = lookup_item(def_id.node, cdata.data());
1260         for impl_doc in reader::tagged_docs(item_doc, tag_items_data_item_extension_impl) {
1261             callback(item_def_id(impl_doc, cdata));
1262         }
1263         return;
1264     }
1265
1266     // Do a reverse lookup beforehand to avoid touching the crate_num
1267     // hash map in the loop below.
1268     if let Some(crate_local_did) = reverse_translate_def_id(cdata, def_id) {
1269         let def_id_u64 = def_to_u64(crate_local_did);
1270
1271         let impls_doc = reader::get_doc(rbml::Doc::new(cdata.data()), tag_impls);
1272         for impl_doc in reader::tagged_docs(impls_doc, tag_impls_impl) {
1273             let impl_trait = reader::get_doc(impl_doc, tag_impls_impl_trait_def_id);
1274             if reader::doc_as_u64(impl_trait) == def_id_u64 {
1275                 callback(item_def_id(impl_doc, cdata));
1276             }
1277         }
1278     }
1279 }
1280
1281 pub fn get_trait_of_item(cdata: Cmd, id: ast::NodeId, tcx: &ty::ctxt)
1282                          -> Option<ast::DefId> {
1283     let item_doc = lookup_item(id, cdata.data());
1284     let parent_item_id = match item_parent_item(cdata, item_doc) {
1285         None => return None,
1286         Some(item_id) => item_id,
1287     };
1288     let parent_item_doc = lookup_item(parent_item_id.node, cdata.data());
1289     match item_family(parent_item_doc) {
1290         Trait => Some(item_def_id(parent_item_doc, cdata)),
1291         Impl | DefaultImpl => {
1292             reader::maybe_get_doc(parent_item_doc, tag_item_trait_ref)
1293                 .map(|_| item_trait_ref(parent_item_doc, tcx, cdata).def_id)
1294         }
1295         _ => None
1296     }
1297 }
1298
1299
1300 pub fn get_native_libraries(cdata: Cmd)
1301                             -> Vec<(cstore::NativeLibraryKind, String)> {
1302     let libraries = reader::get_doc(rbml::Doc::new(cdata.data()),
1303                                     tag_native_libraries);
1304     reader::tagged_docs(libraries, tag_native_libraries_lib).map(|lib_doc| {
1305         let kind_doc = reader::get_doc(lib_doc, tag_native_libraries_kind);
1306         let name_doc = reader::get_doc(lib_doc, tag_native_libraries_name);
1307         let kind: cstore::NativeLibraryKind =
1308             cstore::NativeLibraryKind::from_u32(reader::doc_as_u32(kind_doc)).unwrap();
1309         let name = name_doc.as_str().to_string();
1310         (kind, name)
1311     }).collect()
1312 }
1313
1314 pub fn get_plugin_registrar_fn(data: &[u8]) -> Option<ast::NodeId> {
1315     reader::maybe_get_doc(rbml::Doc::new(data), tag_plugin_registrar_fn)
1316         .map(|doc| reader::doc_as_u32(doc))
1317 }
1318
1319 pub fn each_exported_macro<F>(data: &[u8], intr: &IdentInterner, mut f: F) where
1320     F: FnMut(ast::Name, Vec<ast::Attribute>, String) -> bool,
1321 {
1322     let macros = reader::get_doc(rbml::Doc::new(data), tag_macro_defs);
1323     for macro_doc in reader::tagged_docs(macros, tag_macro_def) {
1324         let name = item_name(intr, macro_doc);
1325         let attrs = get_attributes(macro_doc);
1326         let body = reader::get_doc(macro_doc, tag_macro_def_body);
1327         if !f(name, attrs, body.as_str().to_string()) {
1328             break;
1329         }
1330     }
1331 }
1332
1333 pub fn get_dylib_dependency_formats(cdata: Cmd)
1334     -> Vec<(ast::CrateNum, cstore::LinkagePreference)>
1335 {
1336     let formats = reader::get_doc(rbml::Doc::new(cdata.data()),
1337                                   tag_dylib_dependency_formats);
1338     let mut result = Vec::new();
1339
1340     debug!("found dylib deps: {}", formats.as_str_slice());
1341     for spec in formats.as_str_slice().split(',') {
1342         if spec.is_empty() { continue }
1343         let cnum = spec.split(':').nth(0).unwrap();
1344         let link = spec.split(':').nth(1).unwrap();
1345         let cnum: ast::CrateNum = cnum.parse().unwrap();
1346         let cnum = match cdata.cnum_map.get(&cnum) {
1347             Some(&n) => n,
1348             None => panic!("didn't find a crate in the cnum_map")
1349         };
1350         result.push((cnum, if link == "d" {
1351             cstore::RequireDynamic
1352         } else {
1353             cstore::RequireStatic
1354         }));
1355     }
1356     return result;
1357 }
1358
1359 pub fn get_missing_lang_items(cdata: Cmd)
1360     -> Vec<lang_items::LangItem>
1361 {
1362     let items = reader::get_doc(rbml::Doc::new(cdata.data()), tag_lang_items);
1363     reader::tagged_docs(items, tag_lang_items_missing).map(|missing_docs| {
1364         lang_items::LangItem::from_u32(reader::doc_as_u32(missing_docs)).unwrap()
1365     }).collect()
1366 }
1367
1368 pub fn get_method_arg_names(cdata: Cmd, id: ast::NodeId) -> Vec<String> {
1369     let method_doc = lookup_item(id, cdata.data());
1370     match reader::maybe_get_doc(method_doc, tag_method_argument_names) {
1371         Some(args_doc) => {
1372             reader::tagged_docs(args_doc, tag_method_argument_name).map(|name_doc| {
1373                 name_doc.as_str_slice().to_string()
1374             }).collect()
1375         },
1376         None => vec![],
1377     }
1378 }
1379
1380 pub fn get_reachable_extern_fns(cdata: Cmd) -> Vec<ast::DefId> {
1381     let items = reader::get_doc(rbml::Doc::new(cdata.data()),
1382                                 tag_reachable_extern_fns);
1383     reader::tagged_docs(items, tag_reachable_extern_fn_id).map(|doc| {
1384         ast::DefId {
1385             krate: cdata.cnum,
1386             node: reader::doc_as_u32(doc),
1387         }
1388     }).collect()
1389 }
1390
1391 pub fn is_typedef(cdata: Cmd, id: ast::NodeId) -> bool {
1392     let item_doc = lookup_item(id, cdata.data());
1393     match item_family(item_doc) {
1394         Type => true,
1395         _ => false,
1396     }
1397 }
1398
1399 pub fn is_const_fn(cdata: Cmd, id: ast::NodeId) -> bool {
1400     let item_doc = lookup_item(id, cdata.data());
1401     match fn_constness(item_doc) {
1402         ast::Constness::Const => true,
1403         ast::Constness::NotConst => false,
1404     }
1405 }
1406
1407 pub fn is_impl(cdata: Cmd, id: ast::NodeId) -> bool {
1408     let item_doc = lookup_item(id, cdata.data());
1409     match item_family(item_doc) {
1410         Impl => true,
1411         _ => false,
1412     }
1413 }
1414
1415 fn doc_generics<'tcx>(base_doc: rbml::Doc,
1416                       tcx: &ty::ctxt<'tcx>,
1417                       cdata: Cmd,
1418                       tag: usize)
1419                       -> ty::Generics<'tcx>
1420 {
1421     let doc = reader::get_doc(base_doc, tag);
1422
1423     let mut types = subst::VecPerParamSpace::empty();
1424     for p in reader::tagged_docs(doc, tag_type_param_def) {
1425         let bd = parse_type_param_def_data(
1426             p.data, p.start, cdata.cnum, tcx,
1427             |_, did| translate_def_id(cdata, did));
1428         types.push(bd.space, bd);
1429     }
1430
1431     let mut regions = subst::VecPerParamSpace::empty();
1432     for rp_doc in reader::tagged_docs(doc, tag_region_param_def) {
1433         let ident_str_doc = reader::get_doc(rp_doc,
1434                                             tag_region_param_def_ident);
1435         let name = item_name(&*token::get_ident_interner(), ident_str_doc);
1436         let def_id_doc = reader::get_doc(rp_doc,
1437                                          tag_region_param_def_def_id);
1438         let def_id = translated_def_id(cdata, def_id_doc);
1439
1440         let doc = reader::get_doc(rp_doc, tag_region_param_def_space);
1441         let space = subst::ParamSpace::from_uint(reader::doc_as_u64(doc) as usize);
1442
1443         let doc = reader::get_doc(rp_doc, tag_region_param_def_index);
1444         let index = reader::doc_as_u64(doc) as u32;
1445
1446         let bounds = reader::tagged_docs(rp_doc, tag_items_data_region).map(|p| {
1447             parse_region_data(p.data, cdata.cnum, p.start, tcx,
1448                               |_, did| translate_def_id(cdata, did))
1449         }).collect();
1450
1451         regions.push(space, ty::RegionParameterDef { name: name,
1452                                                      def_id: def_id,
1453                                                      space: space,
1454                                                      index: index,
1455                                                      bounds: bounds });
1456     }
1457
1458     ty::Generics { types: types, regions: regions }
1459 }
1460
1461 fn doc_predicates<'tcx>(base_doc: rbml::Doc,
1462                         tcx: &ty::ctxt<'tcx>,
1463                         cdata: Cmd,
1464                         tag: usize)
1465                         -> ty::GenericPredicates<'tcx>
1466 {
1467     let doc = reader::get_doc(base_doc, tag);
1468
1469     let mut predicates = subst::VecPerParamSpace::empty();
1470     for predicate_doc in reader::tagged_docs(doc, tag_predicate) {
1471         let space_doc = reader::get_doc(predicate_doc, tag_predicate_space);
1472         let space = subst::ParamSpace::from_uint(reader::doc_as_u8(space_doc) as usize);
1473
1474         let data_doc = reader::get_doc(predicate_doc, tag_predicate_data);
1475         let data = parse_predicate_data(data_doc.data, data_doc.start, cdata.cnum, tcx,
1476                                         |_, did| translate_def_id(cdata, did));
1477
1478         predicates.push(space, data);
1479     }
1480
1481     ty::GenericPredicates { predicates: predicates }
1482 }
1483
1484 pub fn is_defaulted_trait(cdata: Cmd, trait_id: ast::NodeId) -> bool {
1485     let trait_doc = lookup_item(trait_id, cdata.data());
1486     assert!(item_family(trait_doc) == Family::Trait);
1487     let defaulted_doc = reader::get_doc(trait_doc, tag_defaulted_trait);
1488     reader::doc_as_u8(defaulted_doc) != 0
1489 }
1490
1491 pub fn is_default_impl(cdata: Cmd, impl_id: ast::NodeId) -> bool {
1492     let impl_doc = lookup_item(impl_id, cdata.data());
1493     item_family(impl_doc) == Family::DefaultImpl
1494 }
1495
1496 pub fn get_imported_filemaps(metadata: &[u8]) -> Vec<codemap::FileMap> {
1497     let crate_doc = rbml::Doc::new(metadata);
1498     let cm_doc = reader::get_doc(crate_doc, tag_codemap);
1499
1500     reader::tagged_docs(cm_doc, tag_codemap_filemap).map(|filemap_doc| {
1501         let mut decoder = reader::Decoder::new(filemap_doc);
1502         Decodable::decode(&mut decoder).unwrap()
1503     }).collect()
1504 }