commit | 1c858da4ae69b422f92107f6fd4a5a784a2a4063 | [log] [tgz] |
---|---|---|
author | Chih-Hung Hsieh <chh@google.com> | Tue Nov 24 01:47:06 2020 +0000 |
committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Tue Nov 24 01:47:06 2020 +0000 |
tree | 50069180fea404c5247eb6b933c6836cda6f2857 | |
parent | f9571b675554e0cc4c2a37e68df0b78a40f5c027 [diff] | |
parent | 0543f0dc8c49e4fdeb57e3c5f4ba921f8c5a1b9a [diff] |
Import hashlink-0.6.0 am: e93fbab9e5 am: 0543f0dc8c Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/hashlink/+/1493280 Change-Id: I09415f0842e511509490afd702b688be4c33d266
This crate is a fork of linked-hash-map that builds on top of hashbrown to implement more up to date versions of LinkedHashMap
LinkedHashSet
, and LruCache
.
One important API change is that when a LinkedHashMap
is used as a LRU cache, it allows you to easily retrieve an entry and move it to the back OR produce a new entry at the back without needlessly repeating key hashing and lookups:
let mut lru_cache = LinkedHashMap::new(); let key = "key".to_owned(); // Try to find my expensive to construct and hash key let _cached_val = match lru_cache.raw_entry_mut().from_key(&key) { RawEntryMut::Occupied(mut occupied) => { // Cache hit, move entry to the back. occupied.to_back(); occupied.into_mut() } RawEntryMut::Vacant(vacant) => { // Insert expensive to construct key and expensive to compute value, // automatically inserted at the back. vacant.insert(key.clone(), 42).1 } };
Or, a simpler way to do the same thing:
let mut lru_cache = LinkedHashMap::new(); let key = "key".to_owned(); let _cached_val = lru_cache .raw_entry_mut() .from_key(&key) .or_insert_with(|| (key.clone(), 42));
This crate contains a decent amount of unsafe code from handling its internal linked list, and the unsafe code has diverged quite a lot from the original linked-hash-map
implementation. It currently passes tests under miri and sanitizers, but it should probably still receive more review and testing, and check for test code coverage.
There is a huge amount of code in this crate that is copied verbatim from linked-hash-map
and hashbrown
, especially tests, associated types like iterators, and things like Debug
impls.
This library is licensed the same as linked-hash-map and hashbrown, it is licensed under either of:
at your option.