src/librustc/hir/def_id.rs - third_party/rust - Git at Google

 // 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;
 use std::fmt;
 use std::u32;

 newtype_index!(CrateNum
     {
         ENCODABLE = custom
         DEBUG_FORMAT = "crate{}",

         /// 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,

         /// A special CrateNum that we use for the tcx.rcache when decoding from
         /// the incr. comp. cache.
         const RESERVED_FOR_INCR_COMP_CACHE = u32::MAX - 2,
     });

 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 {}
 impl serialize::UseSpecializedDecodable for 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 from two
 /// address spaces: DefIndexAddressSpace::Low and DefIndexAddressSpace::High.
 /// This allows us to allocate the DefIndexes of all item-likes
 /// (Items, TraitItems, and ImplItems) into one of these spaces 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 address spaces.

 #[derive(Clone, Eq, Ord, PartialOrd, PartialEq, Hash, Copy)]
 pub struct DefIndex(u32);

 /// The crate root is always assigned index 0 by the AST Map code,
 /// thanks to `NodeCollector::new`.
 pub const CRATE_DEF_INDEX: DefIndex = DefIndex(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 address_space(&self) -> DefIndexAddressSpace {
         match self.0 & 1 {
             0 => DefIndexAddressSpace::Low,
             1 => DefIndexAddressSpace::High,
             _ => unreachable!()
         }
     }

     /// Converts this DefIndex into a zero-based array index.
     /// This index is the offset within the given DefIndexAddressSpace.
     #[inline]
     pub fn as_array_index(&self) -> usize {
         (self.0 >> 1) as usize
     }

     #[inline]
     pub fn from_array_index(i: usize, address_space: DefIndexAddressSpace) -> DefIndex {
         DefIndex::from_raw_u32(((i << 1) | (address_space as usize)) as u32)
     }

     // Proc macros from a proc-macro crate have a kind of virtual DefIndex. This
     // function maps the index of the macro within the crate (which is also the
     // index of the macro in the CrateMetadata::proc_macros array) to the
     // corresponding DefIndex.
     pub fn from_proc_macro_index(proc_macro_index: usize) -> DefIndex {
         let def_index = DefIndex::from_array_index(proc_macro_index,
                                                    DefIndexAddressSpace::High);
         assert!(def_index != CRATE_DEF_INDEX);
         def_index
     }

     // This function is the reverse of from_proc_macro_index() above.
     pub fn to_proc_macro_index(self: DefIndex) -> usize {
         self.as_array_index()
     }

     // Don't use this if you don't know about the DefIndex encoding.
     pub fn from_raw_u32(x: u32) -> DefIndex {
         DefIndex(x)
     }

     // Don't use this if you don't know about the DefIndex encoding.
     pub fn as_raw_u32(&self) -> u32 {
         self.0
     }
 }

 impl serialize::UseSpecializedEncodable for DefIndex {}
 impl serialize::UseSpecializedDecodable for DefIndex {}

 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
 pub enum DefIndexAddressSpace {
     Low = 0,
     High = 1,
 }

 impl DefIndexAddressSpace {
     #[inline]
     pub fn index(&self) -> usize {
         *self as usize
     }
 }

 /// A DefId identifies a particular *definition*, by combining a crate
 /// index and a def index.
 #[derive(Clone, Eq, Ord, PartialOrd, PartialEq, 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({:?}/{}:{}",
                self.krate.index(),
                self.index.address_space().index(),
                self.index.as_array_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.
     #[inline]
     pub fn local(index: DefIndex) -> DefId {
         DefId { krate: LOCAL_CRATE, index: index }
     }

     #[inline]
     pub fn is_local(self) -> bool {
         self.krate == LOCAL_CRATE
     }

     #[inline]
     pub fn to_local(self) -> LocalDefId {
         LocalDefId::from_def_id(self)
     }
 }

 impl serialize::UseSpecializedEncodable for DefId {}
 impl serialize::UseSpecializedDecodable for DefId {}

 /// A LocalDefId is equivalent to a DefId with `krate == LOCAL_CRATE`. Since
 /// we encode this information in the type, we can ensure at compile time that
 /// no DefIds from upstream crates get thrown into the mix. There are quite a
 /// few cases where we know that only DefIds from the local crate are expected
 /// and a DefId from a different crate would signify a bug somewhere. This
 /// is when LocalDefId comes in handy.
 #[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub struct LocalDefId(DefIndex);

 impl LocalDefId {

     #[inline]
     pub fn from_def_id(def_id: DefId) -> LocalDefId {
         assert!(def_id.is_local());
         LocalDefId(def_id.index)
     }

     #[inline]
     pub fn to_def_id(self) -> DefId {
         DefId {
             krate: LOCAL_CRATE,
             index: self.0
         }
     }
 }

 impl fmt::Debug for LocalDefId {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.to_def_id().fmt(f)
     }
 }

 impl serialize::UseSpecializedEncodable for LocalDefId {}
 impl serialize::UseSpecializedDecodable for LocalDefId {}
	// 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;
	use std::fmt;
	use std::u32;

	newtype_index!(CrateNum
	{
	ENCODABLE = custom
	DEBUG_FORMAT = "crate{}",

	/// 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,

	/// A special CrateNum that we use for the tcx.rcache when decoding from
	/// the incr. comp. cache.
	const RESERVED_FOR_INCR_COMP_CACHE = u32::MAX - 2,
	});

	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 {}
	impl serialize::UseSpecializedDecodable for 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 from two
	/// address spaces: DefIndexAddressSpace::Low and DefIndexAddressSpace::High.
	/// This allows us to allocate the DefIndexes of all item-likes
	/// (Items, TraitItems, and ImplItems) into one of these spaces 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 address spaces.

	#[derive(Clone, Eq, Ord, PartialOrd, PartialEq, Hash, Copy)]
	pub struct DefIndex(u32);

	/// The crate root is always assigned index 0 by the AST Map code,
	/// thanks to `NodeCollector::new`.
	pub const CRATE_DEF_INDEX: DefIndex = DefIndex(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 address_space(&self) -> DefIndexAddressSpace {
	match self.0 & 1 {
	0 => DefIndexAddressSpace::Low,
	1 => DefIndexAddressSpace::High,
	_ => unreachable!()
	}
	}

	/// Converts this DefIndex into a zero-based array index.
	/// This index is the offset within the given DefIndexAddressSpace.
	#[inline]
	pub fn as_array_index(&self) -> usize {
	(self.0 >> 1) as usize
	}

	#[inline]
	pub fn from_array_index(i: usize, address_space: DefIndexAddressSpace) -> DefIndex {
	DefIndex::from_raw_u32(((i << 1) \| (address_space as usize)) as u32)
	}

	// Proc macros from a proc-macro crate have a kind of virtual DefIndex. This
	// function maps the index of the macro within the crate (which is also the
	// index of the macro in the CrateMetadata::proc_macros array) to the
	// corresponding DefIndex.
	pub fn from_proc_macro_index(proc_macro_index: usize) -> DefIndex {
	let def_index = DefIndex::from_array_index(proc_macro_index,
	DefIndexAddressSpace::High);
	assert!(def_index != CRATE_DEF_INDEX);
	def_index
	}

	// This function is the reverse of from_proc_macro_index() above.
	pub fn to_proc_macro_index(self: DefIndex) -> usize {
	self.as_array_index()
	}

	// Don't use this if you don't know about the DefIndex encoding.
	pub fn from_raw_u32(x: u32) -> DefIndex {
	DefIndex(x)
	}

	// Don't use this if you don't know about the DefIndex encoding.
	pub fn as_raw_u32(&self) -> u32 {
	self.0
	}
	}

	impl serialize::UseSpecializedEncodable for DefIndex {}
	impl serialize::UseSpecializedDecodable for DefIndex {}

	#[derive(Copy, Clone, Eq, PartialEq, Hash)]
	pub enum DefIndexAddressSpace {
	Low = 0,
	High = 1,
	}

	impl DefIndexAddressSpace {
	#[inline]
	pub fn index(&self) -> usize {
	*self as usize
	}
	}

	/// A DefId identifies a particular definition, by combining a crate
	/// index and a def index.
	#[derive(Clone, Eq, Ord, PartialOrd, PartialEq, 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({:?}/{}:{}",
	self.krate.index(),
	self.index.address_space().index(),
	self.index.as_array_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.
	#[inline]
	pub fn local(index: DefIndex) -> DefId {
	DefId { krate: LOCAL_CRATE, index: index }
	}

	#[inline]
	pub fn is_local(self) -> bool {
	self.krate == LOCAL_CRATE
	}

	#[inline]
	pub fn to_local(self) -> LocalDefId {
	LocalDefId::from_def_id(self)
	}
	}

	impl serialize::UseSpecializedEncodable for DefId {}
	impl serialize::UseSpecializedDecodable for DefId {}

	/// A LocalDefId is equivalent to a DefId with `krate == LOCAL_CRATE`. Since
	/// we encode this information in the type, we can ensure at compile time that
	/// no DefIds from upstream crates get thrown into the mix. There are quite a
	/// few cases where we know that only DefIds from the local crate are expected
	/// and a DefId from a different crate would signify a bug somewhere. This
	/// is when LocalDefId comes in handy.
	#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
	pub struct LocalDefId(DefIndex);

	impl LocalDefId {

	#[inline]
	pub fn from_def_id(def_id: DefId) -> LocalDefId {
	assert!(def_id.is_local());
	LocalDefId(def_id.index)
	}

	#[inline]
	pub fn to_def_id(self) -> DefId {
	DefId {
	krate: LOCAL_CRATE,
	index: self.0
	}
	}
	}

	impl fmt::Debug for LocalDefId {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	self.to_def_id().fmt(f)
	}
	}

	impl serialize::UseSpecializedEncodable for LocalDefId {}
	impl serialize::UseSpecializedDecodable for LocalDefId {}