rm LRUCache

Summary: Appears to be unused.

Reviewed By: danielbuechele

Differential Revision: D16710463

fbshipit-source-id: 00ba195689ffc96700ae623fd02fb806b9730272

src/utils/LRUCache.js

@@ -1,172 +0,0 @@
-/**
- * Copyright 2018-present Facebook.
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- * @format
- */
-
-class ListElement<K, V> {
-  constructor(cache: LRUCache<K, V>, key: K, value: V) {
-    this.cache = cache;
-    this.before = undefined;
-    this.next = undefined;
-    this.set(key, value);
-  }
-
-  creationTime: number;
-  cache: LRUCache<K, V>;
-  before: ?ListElement<K, V>;
-  next: ?ListElement<K, V>;
-  key: K;
-  value: V;
-
-  set(key: K, value: V) {
-    this.key = key;
-    this.value = value;
-    this.creationTime = Date.now();
-  }
-
-  hit() {
-    this.detach();
-    this.attach();
-  }
-
-  attach() {
-    this.before = undefined;
-    this.next = this.cache.head;
-    this.cache.head = this;
-
-    const {next} = this;
-    if (next) {
-      next.before = this;
-    } else {
-      this.cache.tail = this;
-    }
-
-    this.cache.size++;
-  }
-
-  detach() {
-    const {before, next} = this;
-
-    if (before) {
-      before.next = next;
-    } else {
-      this.cache.head = next;
-    }
-
-    if (next) {
-      next.before = before;
-    } else {
-      this.cache.tail = before;
-    }
-
-    this.cache.size--;
-  }
-}
-
-type LRUCacheOptions = {|
-  maxSize: number,
-  maxAge?: number,
-|};
-
-export default class LRUCache<K, V> {
-  constructor(options: LRUCacheOptions) {
-    this.maxSize = options.maxSize;
-    this.maxAge = options.maxAge;
-    this.clear();
-  }
-
-  maxSize: number;
-  maxAge: ?number;
-  size: number;
-  data: Map<K, ListElement<K, V>>;
-  tail: ?ListElement<K, V>;
-  head: ?ListElement<K, V>;
-
-  clear() {
-    this.size = 0;
-    this.data = new Map();
-    this.tail = undefined;
-    this.head = undefined;
-  }
-
-  has(key: K): boolean {
-    return this.data.has(key);
-  }
-
-  get(key: K, hit?: boolean = true): ?V {
-    const cacheVal = this.data.get(key);
-    if (!cacheVal) {
-      return;
-    }
-
-    const {maxAge} = this;
-    if (maxAge != null) {
-      const timeNow = Date.now();
-      const timeSinceCreation = timeNow - cacheVal.creationTime;
-      if (timeSinceCreation > maxAge) {
-        this.delete(key);
-        return;
-      }
-    }
-
-    if (hit) {
-      cacheVal.hit();
-    }
-
-    return cacheVal.value;
-  }
-
-  pop(): ?ListElement<K, V> {
-    const {tail} = this;
-    if (!tail) {
-      return;
-    }
-
-    this.delete(tail.key);
-
-    tail.next = undefined;
-    tail.before = undefined;
-
-    return tail;
-  }
-
-  set(key: K, val: V, hit?: boolean = true) {
-    const actual = this.data.get(key);
-
-    if (actual) {
-      actual.value = val;
-      if (hit) {
-        actual.hit();
-      }
-    } else {
-      let cacheVal: ?ListElement<K, V>;
-
-      if (this.size >= this.maxSize) {
-        cacheVal = this.pop();
-
-        if (cacheVal) {
-          cacheVal.set(key, val);
-        }
-      }
-
-      if (!cacheVal) {
-        cacheVal = new ListElement(this, key, val);
-      }
-
-      this.data.set(key, cacheVal);
-      cacheVal.attach();
-    }
-  }
-
-  delete(key: K) {
-    const val = this.data.get(key);
-    if (!val) {
-      return;
-    }
-
-    val.detach();
-    this.data.delete(key);
-  }
-}