src/librustc/hir/def_id.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use ty;
  12
  13 use rustc_data_structures::indexed_vec::Idx;
  14 use serialize::{self, Encoder, Decoder};
  15
  16 use std::fmt;
  17 use std::u32;
  18
  19 #[derive(Clone, Copy, Eq, Ord, PartialOrd, PartialEq, Hash, Debug)]
  20 pub struct CrateNum(u32);
  21
  22 impl Idx for CrateNum {
  23     fn new(value: usize) -> Self {
  24         assert!(value < (u32::MAX) as usize);
  25         CrateNum(value as u32)
  26     }
  27
  28     fn index(self) -> usize {
  29         self.0 as usize
  30     }
  31 }
  32
  33 /// Item definitions in the currently-compiled crate would have the CrateNum
  34 /// LOCAL_CRATE in their DefId.
  35 pub const LOCAL_CRATE: CrateNum = CrateNum(0);
  36
  37 impl CrateNum {
  38     pub fn new(x: usize) -> CrateNum {
  39         assert!(x < (u32::MAX as usize));
  40         CrateNum(x as u32)
  41     }
  42
  43     pub fn from_u32(x: u32) -> CrateNum {
  44         CrateNum(x)
  45     }
  46
  47     pub fn as_usize(&self) -> usize {
  48         self.0 as usize
  49     }
  50
  51     pub fn as_u32(&self) -> u32 {
  52         self.0
  53     }
  54 }
  55
  56 impl fmt::Display for CrateNum {
  57     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  58         fmt::Display::fmt(&self.0, f)
  59     }
  60 }
  61
  62 impl serialize::UseSpecializedEncodable for CrateNum {
  63     fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
  64         s.emit_u32(self.0)
  65     }
  66 }
  67
  68 impl serialize::UseSpecializedDecodable for CrateNum {
  69     fn default_decode<D: Decoder>(d: &mut D) -> Result<CrateNum, D::Error> {
  70         d.read_u32().map(CrateNum)
  71     }
  72 }
  73
  74 /// A DefIndex is an index into the hir-map for a crate, identifying a
  75 /// particular definition. It should really be considered an interned
  76 /// shorthand for a particular DefPath.
  77 #[derive(Clone, Debug, Eq, Ord, PartialOrd, PartialEq, RustcEncodable,
  78            RustcDecodable, Hash, Copy)]
  79 pub struct DefIndex(u32);
  80
  81 impl DefIndex {
  82     pub fn new(x: usize) -> DefIndex {
  83         assert!(x < (u32::MAX as usize));
  84         DefIndex(x as u32)
  85     }
  86
  87     pub fn from_u32(x: u32) -> DefIndex {
  88         DefIndex(x)
  89     }
  90
  91     pub fn as_usize(&self) -> usize {
  92         self.0 as usize
  93     }
  94
  95     pub fn as_u32(&self) -> u32 {
  96         self.0
  97     }
  98 }
  99
 100 /// The crate root is always assigned index 0 by the AST Map code,
 101 /// thanks to `NodeCollector::new`.
 102 pub const CRATE_DEF_INDEX: DefIndex = DefIndex(0);
 103
 104 /// A DefId identifies a particular *definition*, by combining a crate
 105 /// index and a def index.
 106 #[derive(Clone, Eq, Ord, PartialOrd, PartialEq, RustcEncodable, RustcDecodable, Hash, Copy)]
 107 pub struct DefId {
 108     pub krate: CrateNum,
 109     pub index: DefIndex,
 110 }
 111
 112 impl fmt::Debug for DefId {
 113     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 114         write!(f, "DefId {{ krate: {:?}, node: {:?}",
 115                self.krate, self.index)?;
 116
 117         ty::tls::with_opt(|opt_tcx| {
 118             if let Some(tcx) = opt_tcx {
 119                 if let Some(def_path) = tcx.opt_def_path(*self) {
 120                     write!(f, " => {}", def_path.to_string(tcx))?;
 121                 }
 122             }
 123             Ok(())
 124         })?;
 125
 126         write!(f, " }}")
 127     }
 128 }
 129
 130
 131 impl DefId {
 132     pub fn local(index: DefIndex) -> DefId {
 133         DefId { krate: LOCAL_CRATE, index: index }
 134     }
 135
 136     pub fn is_local(&self) -> bool {
 137         self.krate == LOCAL_CRATE
 138     }
 139 }