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def_id.rs
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def_id.rs
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// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use ty;
use rustc_data_structures::indexed_vec::Idx;
use serialize::{self, Encoder, Decoder};
use std::fmt;
use std::u32;
newtype_index!(CrateNum
{
derive[Debug]
ENCODABLE = custom
/// Item definitions in the currently-compiled crate would have the CrateNum
/// LOCAL_CRATE in their DefId.
const LOCAL_CRATE = 0,
/// Virtual crate for builtin macros
// FIXME(jseyfried): this is also used for custom derives until proc-macro crates get
// `CrateNum`s.
const BUILTIN_MACROS_CRATE = u32::MAX,
/// A CrateNum value that indicates that something is wrong.
const INVALID_CRATE = u32::MAX - 1,
});
impl CrateNum {
pub fn new(x: usize) -> CrateNum {
assert!(x < (u32::MAX as usize));
CrateNum(x as u32)
}
pub fn from_u32(x: u32) -> CrateNum {
CrateNum(x)
}
pub fn as_usize(&self) -> usize {
self.0 as usize
}
pub fn as_u32(&self) -> u32 {
self.0
}
pub fn as_def_id(&self) -> DefId { DefId { krate: *self, index: CRATE_DEF_INDEX } }
}
impl fmt::Display for CrateNum {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::Display::fmt(&self.0, f)
}
}
impl serialize::UseSpecializedEncodable for CrateNum {
fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
s.emit_u32(self.0)
}
}
impl serialize::UseSpecializedDecodable for CrateNum {
fn default_decode<D: Decoder>(d: &mut D) -> Result<CrateNum, D::Error> {
d.read_u32().map(CrateNum)
}
}
/// A DefIndex is an index into the hir-map for a crate, identifying a
/// particular definition. It should really be considered an interned
/// shorthand for a particular DefPath.
///
/// At the moment we are allocating the numerical values of DefIndexes into two
/// ranges: the "low" range (starting at zero) and the "high" range (starting at
/// DEF_INDEX_HI_START). This allows us to allocate the DefIndexes of all
/// item-likes (Items, TraitItems, and ImplItems) into one of these ranges and
/// consequently use a simple array for lookup tables keyed by DefIndex and
/// known to be densely populated. This is especially important for the HIR map.
///
/// Since the DefIndex is mostly treated as an opaque ID, you probably
/// don't have to care about these ranges.
newtype_index!(DefIndex
{
DEBUG_FORMAT = custom,
/// The start of the "high" range of DefIndexes.
const DEF_INDEX_HI_START = 1 << 31,
/// The crate root is always assigned index 0 by the AST Map code,
/// thanks to `NodeCollector::new`.
const CRATE_DEF_INDEX = 0,
});
impl fmt::Debug for DefIndex {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f,
"DefIndex({}:{})",
self.address_space().index(),
self.as_array_index())
}
}
impl DefIndex {
#[inline]
pub fn from_u32(x: u32) -> DefIndex {
DefIndex(x)
}
#[inline]
pub fn as_usize(&self) -> usize {
self.0 as usize
}
#[inline]
pub fn as_u32(&self) -> u32 {
self.0
}
#[inline]
pub fn address_space(&self) -> DefIndexAddressSpace {
if self.0 < DEF_INDEX_HI_START.0 {
DefIndexAddressSpace::Low
} else {
DefIndexAddressSpace::High
}
}
/// Converts this DefIndex into a zero-based array index.
/// This index is the offset within the given "range" of the DefIndex,
/// that is, if the DefIndex is part of the "high" range, the resulting
/// index will be (DefIndex - DEF_INDEX_HI_START).
#[inline]
pub fn as_array_index(&self) -> usize {
(self.0 & !DEF_INDEX_HI_START.0) as usize
}
pub fn from_array_index(i: usize, address_space: DefIndexAddressSpace) -> DefIndex {
DefIndex::new(address_space.start() + i)
}
}
#[derive(Copy, Clone, Eq, PartialEq, Hash)]
pub enum DefIndexAddressSpace {
Low = 0,
High = 1,
}
impl DefIndexAddressSpace {
#[inline]
pub fn index(&self) -> usize {
*self as usize
}
#[inline]
pub fn start(&self) -> usize {
self.index() * DEF_INDEX_HI_START.as_usize()
}
}
/// A DefId identifies a particular *definition*, by combining a crate
/// index and a def index.
#[derive(Clone, Eq, Ord, PartialOrd, PartialEq, RustcEncodable, RustcDecodable, Hash, Copy)]
pub struct DefId {
pub krate: CrateNum,
pub index: DefIndex,
}
impl fmt::Debug for DefId {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "DefId {{ krate: {:?}, index: {:?}",
self.krate, self.index)?;
ty::tls::with_opt(|opt_tcx| {
if let Some(tcx) = opt_tcx {
write!(f, " => {}", tcx.def_path_debug_str(*self))?;
}
Ok(())
})?;
write!(f, " }}")
}
}
impl DefId {
/// Make a local `DefId` with the given index.
pub fn local(index: DefIndex) -> DefId {
DefId { krate: LOCAL_CRATE, index: index }
}
pub fn is_local(&self) -> bool {
self.krate == LOCAL_CRATE
}
}