wroclaw-git-backups/nix
1
0
Fork 0
mirror of https://github.com/NixOS/nix synced 2025-06-27 16:51:15 +02:00
Code Activity

Extend internal API docs, part 2

Browse source 
Picking up from #8111.

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
This commit is contained in:
John Ericson 2023-03-26 21:12:25 -04:00
parent 8ae9d66940
commit abd5e7dec0
32 changed files with 640 additions and 359 deletions
Download patch file Download diff file Expand all files Collapse all files

22
src/libutil/lru-cache.hh
View file

@ -7,7 +7,9 @@
namespace nix {
/* A simple least-recently used cache. Not thread-safe. */
/**
* A simple least-recently used cache. Not thread-safe.
*/
template<typename Key, typename Value>
class LRUCache
{
@ -31,7 +33,9 @@ public:
LRUCache(size_t capacity) : capacity(capacity) { }
/* Insert or upsert an item in the cache. */
/**
* Insert or upsert an item in the cache.
*/
void upsert(const Key & key, const Value & value)
{
if (capacity == 0) return;
@ -39,7 +43,9 @@ public:
erase(key);
if (data.size() >= capacity) {
/* Retire the oldest item. */
/**
* Retire the oldest item.
*/
auto oldest = lru.begin();
data.erase(*oldest);
lru.erase(oldest);
@ -63,14 +69,18 @@ public:
return true;
}
/* Look up an item in the cache. If it exists, it becomes the most
recently used item. */
/**
* Look up an item in the cache. If it exists, it becomes the most
* recently used item.
* */
std::optional<Value> get(const Key & key)
{
auto i = data.find(key);
if (i == data.end()) return {};
/* Move this item to the back of the LRU list. */
/**
* Move this item to the back of the LRU list.
*/
lru.erase(i->second.first.it);
auto j = lru.insert(lru.end(), i);
i->second.first.it = j;