commit | d2eaf68e873958bc3c91064aac03a21a7ae36e89 | [log] [tgz] |
---|---|---|
author | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Thu Dec 16 02:07:06 2021 +0000 |
committer | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Thu Dec 16 02:07:06 2021 +0000 |
tree | 3c2abb16a61cdcb6c665836da86505adbc9db9e0 | |
parent | 5f533e026a9a2ebb762cd31802c22d51631b8502 [diff] | |
parent | 0927990edf14645203e733b6556a968b7f4177f6 [diff] |
Snap for 8006021 from 0927990edf14645203e733b6556a968b7f4177f6 to tm-release Change-Id: I90f9167033072ef52fc355b2b684693ee0cc410a
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.