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lru.cljc
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lru.cljc
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(ns ^:no-doc datascript.lru)
(declare assoc-lru cleanup-lru)
#?(:cljs
(deftype LRU [key-value gen-key key-gen gen limit]
IAssociative
(-assoc [this k v] (assoc-lru this k v))
(-contains-key? [_ k] (-contains-key? key-value k))
ILookup
(-lookup [_ k] (-lookup key-value k nil))
(-lookup [_ k nf] (-lookup key-value k nf))
IPrintWithWriter
(-pr-writer [_ writer opts]
(-pr-writer (persistent! key-value) writer opts)))
:clj
(deftype LRU [^clojure.lang.Associative key-value gen-key key-gen gen limit]
clojure.lang.ILookup
(valAt [_ k] (.valAt key-value k))
(valAt [_ k not-found] (.valAt key-value k not-found))
clojure.lang.Associative
(containsKey [_ k] (.containsKey key-value k))
(entryAt [_ k] (.entryAt key-value k))
(assoc [this k v] (assoc-lru this k v))))
(defn assoc-lru [^LRU lru k v]
(let [key-value (.-key-value lru)
gen-key (.-gen-key lru)
key-gen (.-key-gen lru)
gen (.-gen lru)
limit (.-limit lru)]
(if-let [g (key-gen k nil)]
(->LRU key-value
(-> gen-key
(dissoc g)
(assoc gen k))
(assoc key-gen k gen)
(inc gen)
limit)
(cleanup-lru
(->LRU (assoc key-value k v)
(assoc gen-key gen k)
(assoc key-gen k gen)
(inc gen)
limit)))))
(defn cleanup-lru [^LRU lru]
(if (> (count (.-key-value lru)) (.-limit lru))
(let [key-value (.-key-value lru)
gen-key (.-gen-key lru)
key-gen (.-key-gen lru)
gen (.-gen lru)
limit (.-limit lru)
[g k] (first gen-key)]
(->LRU (dissoc key-value k)
(dissoc gen-key g)
(dissoc key-gen k)
gen
limit))
lru))
(defn lru [limit]
(->LRU {} (sorted-map) {} 0 limit))