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::EncodeContext;
7use crate::rmeta::decoder::BlobDecodeContext;
8
9pub(crate) enum DefPathHashMapRef<'tcx> {
10    OwnedFromMetadata(odht::HashTable<HashMapConfig, OwnedSlice>),
11    BorrowedFromTcx(&'tcx DefPathHashMap),
12}
13
14impl DefPathHashMapRef<'_> {
15    #[inline]
16    pub(crate) fn def_path_hash_to_def_index(
17        &self,
18        def_path_hash: &DefPathHash,
19    ) -> Option<DefIndex> {
20        match *self {
21            DefPathHashMapRef::OwnedFromMetadata(ref map) => map.get(&def_path_hash.local_hash()),
22            DefPathHashMapRef::BorrowedFromTcx(_) => {
23                panic!("DefPathHashMap::BorrowedFromTcx variant only exists for serialization")
24            }
25        }
26    }
27}
28
29impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for DefPathHashMapRef<'tcx> {
30    fn encode(&self, e: &mut EncodeContext<'a, 'tcx>) {
31        match *self {
32            DefPathHashMapRef::BorrowedFromTcx(def_path_hash_map) => {
33                let bytes = def_path_hash_map.raw_bytes();
34                e.emit_usize(bytes.len());
35                e.emit_raw_bytes(bytes);
36            }
37            DefPathHashMapRef::OwnedFromMetadata(_) => {
38                panic!("DefPathHashMap::OwnedFromMetadata variant only exists for deserialization")
39            }
40        }
41    }
42}
43
44impl<'a> Decodable<BlobDecodeContext<'a>> for DefPathHashMapRef<'static> {
45    fn decode(d: &mut BlobDecodeContext<'a>) -> DefPathHashMapRef<'static> {
46        let len = d.read_usize();
47        let pos = d.position();
48        let o = d.blob().bytes().clone().slice(|blob| &blob[pos..pos + len]);
49
50        // Although we already have the data we need via the `OwnedSlice`, we still need
51        // to advance the `DecodeContext`'s position so it's in a valid state after
52        // the method. We use `read_raw_bytes()` for that.
53        let _ = d.read_raw_bytes(len);
54
55        let inner = odht::HashTable::from_raw_bytes(o).unwrap_or_else(|e| {
56            panic!("decode error: {e}");
57        });
58        DefPathHashMapRef::OwnedFromMetadata(inner)
59    }
60}
rustc_metadata/rmeta/def_path_hash_map.rs

rustc_metadata/rmeta/
def_path_hash_map.rs
