rustc_metadata/rmeta/
def_path_hash_map.rs

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1use rustc_data_structures::owned_slice::OwnedSlice;
2use rustc_hir::def_path_hash_map::{Config as HashMapConfig, DefPathHashMap};
3use rustc_middle::parameterized_over_tcx;
4use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
5use rustc_span::def_id::{DefIndex, DefPathHash};
6
7use crate::rmeta::{DecodeContext, EncodeContext};
8
9pub(crate) enum DefPathHashMapRef<'tcx> {
10    OwnedFromMetadata(odht::HashTable<HashMapConfig, OwnedSlice>),
11    BorrowedFromTcx(&'tcx DefPathHashMap),
12}
13
14parameterized_over_tcx! {
15    DefPathHashMapRef,
16}
17
18impl DefPathHashMapRef<'_> {
19    #[inline]
20    pub(crate) fn def_path_hash_to_def_index(&self, def_path_hash: &DefPathHash) -> DefIndex {
21        match *self {
22            DefPathHashMapRef::OwnedFromMetadata(ref map) => {
23                map.get(&def_path_hash.local_hash()).unwrap()
24            }
25            DefPathHashMapRef::BorrowedFromTcx(_) => {
26                panic!("DefPathHashMap::BorrowedFromTcx variant only exists for serialization")
27            }
28        }
29    }
30}
31
32impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for DefPathHashMapRef<'tcx> {
33    fn encode(&self, e: &mut EncodeContext<'a, 'tcx>) {
34        match *self {
35            DefPathHashMapRef::BorrowedFromTcx(def_path_hash_map) => {
36                let bytes = def_path_hash_map.raw_bytes();
37                e.emit_usize(bytes.len());
38                e.emit_raw_bytes(bytes);
39            }
40            DefPathHashMapRef::OwnedFromMetadata(_) => {
41                panic!("DefPathHashMap::OwnedFromMetadata variant only exists for deserialization")
42            }
43        }
44    }
45}
46
47impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for DefPathHashMapRef<'static> {
48    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> DefPathHashMapRef<'static> {
49        let len = d.read_usize();
50        let pos = d.position();
51        let o = d.blob().bytes().clone().slice(|blob| &blob[pos..pos + len]);
52
53        // Although we already have the data we need via the `OwnedSlice`, we still need
54        // to advance the `DecodeContext`'s position so it's in a valid state after
55        // the method. We use `read_raw_bytes()` for that.
56        let _ = d.read_raw_bytes(len);
57
58        let inner = odht::HashTable::from_raw_bytes(o).unwrap_or_else(|e| {
59            panic!("decode error: {e}");
60        });
61        DefPathHashMapRef::OwnedFromMetadata(inner)
62    }
63}
rustc_metadata/rmeta/def_path_hash_map.rs

rustc_metadata/rmeta/
def_path_hash_map.rs
