1 use crate::rmeta::DecodeContext;
2 use crate::rmeta::EncodeContext;
3 use crate::rmeta::MetadataBlob;
4 use rustc_data_structures::owning_ref::OwningRef;
5 use rustc_hir::def_path_hash_map::{Config as HashMapConfig, DefPathHashMap};
6 use rustc_middle::parameterized_over_tcx;
7 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
8 use rustc_span::def_id::{DefIndex, DefPathHash};
10 pub(crate) enum DefPathHashMapRef<'tcx> {
11 OwnedFromMetadata(odht::HashTable<HashMapConfig, OwningRef<MetadataBlob, [u8]>>),
12 BorrowedFromTcx(&'tcx DefPathHashMap),
15 parameterized_over_tcx! {
19 impl DefPathHashMapRef<'_> {
21 pub fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> DefIndex {
23 DefPathHashMapRef::OwnedFromMetadata(ref map) => map.get(def_path_hash).unwrap(),
24 DefPathHashMapRef::BorrowedFromTcx(_) => {
25 panic!("DefPathHashMap::BorrowedFromTcx variant only exists for serialization")
31 impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for DefPathHashMapRef<'tcx> {
32 fn encode(&self, e: &mut EncodeContext<'a, 'tcx>) {
34 DefPathHashMapRef::BorrowedFromTcx(def_path_hash_map) => {
35 let bytes = def_path_hash_map.raw_bytes();
36 e.emit_usize(bytes.len());
37 e.emit_raw_bytes(bytes);
39 DefPathHashMapRef::OwnedFromMetadata(_) => {
40 panic!("DefPathHashMap::OwnedFromMetadata variant only exists for deserialization")
46 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for DefPathHashMapRef<'static> {
47 fn decode(d: &mut DecodeContext<'a, 'tcx>) -> DefPathHashMapRef<'static> {
48 // Import TyDecoder so we can access the DecodeContext::position() method
49 use crate::rustc_middle::ty::codec::TyDecoder;
51 let len = d.read_usize();
52 let pos = d.position();
53 let o = OwningRef::new(d.blob().clone()).map(|x| &x[pos..pos + len]);
55 // Although we already have the data we need via the OwningRef, we still need
56 // to advance the DecodeContext's position so it's in a valid state after
57 // the method. We use read_raw_bytes() for that.
58 let _ = d.read_raw_bytes(len);
60 let inner = odht::HashTable::from_raw_bytes(o).unwrap_or_else(|e| {
61 panic!("decode error: {}", e);
63 DefPathHashMapRef::OwnedFromMetadata(inner)