rustc_metadata/rmeta/
def_path_hash_map.rs

1use rustc_data_structures::owned_slice::OwnedSlice;
2use rustc_hir::def_path_hash_map::{Config as HashMapConfig, DefPathHashMap};
3use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
4use rustc_span::def_id::{DefIndex, DefPathHash};
5
6use crate::rmeta::{DecodeContext, EncodeContext};
7
8pub(crate) enum DefPathHashMapRef<'tcx> {
9    OwnedFromMetadata(odht::HashTable<HashMapConfig, OwnedSlice>),
10    BorrowedFromTcx(&'tcx DefPathHashMap),
11}
12
13impl DefPathHashMapRef<'_> {
14    #[inline]
15    pub(crate) fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> DefIndex {
16        match *self {
17            DefPathHashMapRef::OwnedFromMetadata(ref map) => {
18                map.get(&def_path_hash.local_hash()).unwrap()
19            }
20            DefPathHashMapRef::BorrowedFromTcx(_) => {
21                panic!("DefPathHashMap::BorrowedFromTcx variant only exists for serialization")
22            }
23        }
24    }
25}
26
27impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for DefPathHashMapRef<'tcx> {
28    fn encode(&self, e: &mut EncodeContext<'a, 'tcx>) {
29        match *self {
30            DefPathHashMapRef::BorrowedFromTcx(def_path_hash_map) => {
31                let bytes = def_path_hash_map.raw_bytes();
32                e.emit_usize(bytes.len());
33                e.emit_raw_bytes(bytes);
34            }
35            DefPathHashMapRef::OwnedFromMetadata(_) => {
36                panic!("DefPathHashMap::OwnedFromMetadata variant only exists for deserialization")
37            }
38        }
39    }
40}
41
42impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for DefPathHashMapRef<'static> {
43    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> DefPathHashMapRef<'static> {
44        let len = d.read_usize();
45        let pos = d.position();
46        let o = d.blob().bytes().clone().slice(|blob| &blob[pos..pos + len]);
47
48        // Although we already have the data we need via the `OwnedSlice`, we still need
49        // to advance the `DecodeContext`'s position so it's in a valid state after
50        // the method. We use `read_raw_bytes()` for that.
51        let _ = d.read_raw_bytes(len);
52
53        let inner = odht::HashTable::from_raw_bytes(o).unwrap_or_else(|e| {
54            panic!("decode error: {e}");
55        });
56        DefPathHashMapRef::OwnedFromMetadata(inner)
57    }
58}
rustc_metadata/rmeta/def_path_hash_map.rs

rustc_metadata/rmeta/
def_path_hash_map.rs
