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author | Minteck <contact@minteck.org> | 2022-08-21 17:31:56 +0200 |
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committer | Minteck <contact@minteck.org> | 2022-08-21 17:31:56 +0200 |
commit | a2df9a69dcc14cb70118cda2ded499055e7ee358 (patch) | |
tree | 6dd283e4e9452d38bce81ddaaae49b5335755842 /together/node_modules/lru-cache/index.js | |
parent | 84dd0735820b16b60f600284d35183d76547a71f (diff) | |
download | pluralconnect-a2df9a69dcc14cb70118cda2ded499055e7ee358.tar.gz pluralconnect-a2df9a69dcc14cb70118cda2ded499055e7ee358.tar.bz2 pluralconnect-a2df9a69dcc14cb70118cda2ded499055e7ee358.zip |
m. update
Diffstat (limited to 'together/node_modules/lru-cache/index.js')
-rw-r--r-- | together/node_modules/lru-cache/index.js | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/together/node_modules/lru-cache/index.js b/together/node_modules/lru-cache/index.js new file mode 100644 index 0000000..573b6b8 --- /dev/null +++ b/together/node_modules/lru-cache/index.js @@ -0,0 +1,334 @@ +'use strict' + +// A linked list to keep track of recently-used-ness +const Yallist = require('yallist') + +const MAX = Symbol('max') +const LENGTH = Symbol('length') +const LENGTH_CALCULATOR = Symbol('lengthCalculator') +const ALLOW_STALE = Symbol('allowStale') +const MAX_AGE = Symbol('maxAge') +const DISPOSE = Symbol('dispose') +const NO_DISPOSE_ON_SET = Symbol('noDisposeOnSet') +const LRU_LIST = Symbol('lruList') +const CACHE = Symbol('cache') +const UPDATE_AGE_ON_GET = Symbol('updateAgeOnGet') + +const naiveLength = () => 1 + +// lruList is a yallist where the head is the youngest +// item, and the tail is the oldest. the list contains the Hit +// objects as the entries. +// Each Hit object has a reference to its Yallist.Node. This +// never changes. +// +// cache is a Map (or PseudoMap) that matches the keys to +// the Yallist.Node object. +class LRUCache { + constructor (options) { + if (typeof options === 'number') + options = { max: options } + + if (!options) + options = {} + + if (options.max && (typeof options.max !== 'number' || options.max < 0)) + throw new TypeError('max must be a non-negative number') + // Kind of weird to have a default max of Infinity, but oh well. + const max = this[MAX] = options.max || Infinity + + const lc = options.length || naiveLength + this[LENGTH_CALCULATOR] = (typeof lc !== 'function') ? naiveLength : lc + this[ALLOW_STALE] = options.stale || false + if (options.maxAge && typeof options.maxAge !== 'number') + throw new TypeError('maxAge must be a number') + this[MAX_AGE] = options.maxAge || 0 + this[DISPOSE] = options.dispose + this[NO_DISPOSE_ON_SET] = options.noDisposeOnSet || false + this[UPDATE_AGE_ON_GET] = options.updateAgeOnGet || false + this.reset() + } + + // resize the cache when the max changes. + set max (mL) { + if (typeof mL !== 'number' || mL < 0) + throw new TypeError('max must be a non-negative number') + + this[MAX] = mL || Infinity + trim(this) + } + get max () { + return this[MAX] + } + + set allowStale (allowStale) { + this[ALLOW_STALE] = !!allowStale + } + get allowStale () { + return this[ALLOW_STALE] + } + + set maxAge (mA) { + if (typeof mA !== 'number') + throw new TypeError('maxAge must be a non-negative number') + + this[MAX_AGE] = mA + trim(this) + } + get maxAge () { + return this[MAX_AGE] + } + + // resize the cache when the lengthCalculator changes. + set lengthCalculator (lC) { + if (typeof lC !== 'function') + lC = naiveLength + + if (lC !== this[LENGTH_CALCULATOR]) { + this[LENGTH_CALCULATOR] = lC + this[LENGTH] = 0 + this[LRU_LIST].forEach(hit => { + hit.length = this[LENGTH_CALCULATOR](hit.value, hit.key) + this[LENGTH] += hit.length + }) + } + trim(this) + } + get lengthCalculator () { return this[LENGTH_CALCULATOR] } + + get length () { return this[LENGTH] } + get itemCount () { return this[LRU_LIST].length } + + rforEach (fn, thisp) { + thisp = thisp || this + for (let walker = this[LRU_LIST].tail; walker !== null;) { + const prev = walker.prev + forEachStep(this, fn, walker, thisp) + walker = prev + } + } + + forEach (fn, thisp) { + thisp = thisp || this + for (let walker = this[LRU_LIST].head; walker !== null;) { + const next = walker.next + forEachStep(this, fn, walker, thisp) + walker = next + } + } + + keys () { + return this[LRU_LIST].toArray().map(k => k.key) + } + + values () { + return this[LRU_LIST].toArray().map(k => k.value) + } + + reset () { + if (this[DISPOSE] && + this[LRU_LIST] && + this[LRU_LIST].length) { + this[LRU_LIST].forEach(hit => this[DISPOSE](hit.key, hit.value)) + } + + this[CACHE] = new Map() // hash of items by key + this[LRU_LIST] = new Yallist() // list of items in order of use recency + this[LENGTH] = 0 // length of items in the list + } + + dump () { + return this[LRU_LIST].map(hit => + isStale(this, hit) ? false : { + k: hit.key, + v: hit.value, + e: hit.now + (hit.maxAge || 0) + }).toArray().filter(h => h) + } + + dumpLru () { + return this[LRU_LIST] + } + + set (key, value, maxAge) { + maxAge = maxAge || this[MAX_AGE] + + if (maxAge && typeof maxAge !== 'number') + throw new TypeError('maxAge must be a number') + + const now = maxAge ? Date.now() : 0 + const len = this[LENGTH_CALCULATOR](value, key) + + if (this[CACHE].has(key)) { + if (len > this[MAX]) { + del(this, this[CACHE].get(key)) + return false + } + + const node = this[CACHE].get(key) + const item = node.value + + // dispose of the old one before overwriting + // split out into 2 ifs for better coverage tracking + if (this[DISPOSE]) { + if (!this[NO_DISPOSE_ON_SET]) + this[DISPOSE](key, item.value) + } + + item.now = now + item.maxAge = maxAge + item.value = value + this[LENGTH] += len - item.length + item.length = len + this.get(key) + trim(this) + return true + } + + const hit = new Entry(key, value, len, now, maxAge) + + // oversized objects fall out of cache automatically. + if (hit.length > this[MAX]) { + if (this[DISPOSE]) + this[DISPOSE](key, value) + + return false + } + + this[LENGTH] += hit.length + this[LRU_LIST].unshift(hit) + this[CACHE].set(key, this[LRU_LIST].head) + trim(this) + return true + } + + has (key) { + if (!this[CACHE].has(key)) return false + const hit = this[CACHE].get(key).value + return !isStale(this, hit) + } + + get (key) { + return get(this, key, true) + } + + peek (key) { + return get(this, key, false) + } + + pop () { + const node = this[LRU_LIST].tail + if (!node) + return null + + del(this, node) + return node.value + } + + del (key) { + del(this, this[CACHE].get(key)) + } + + load (arr) { + // reset the cache + this.reset() + + const now = Date.now() + // A previous serialized cache has the most recent items first + for (let l = arr.length - 1; l >= 0; l--) { + const hit = arr[l] + const expiresAt = hit.e || 0 + if (expiresAt === 0) + // the item was created without expiration in a non aged cache + this.set(hit.k, hit.v) + else { + const maxAge = expiresAt - now + // dont add already expired items + if (maxAge > 0) { + this.set(hit.k, hit.v, maxAge) + } + } + } + } + + prune () { + this[CACHE].forEach((value, key) => get(this, key, false)) + } +} + +const get = (self, key, doUse) => { + const node = self[CACHE].get(key) + if (node) { + const hit = node.value + if (isStale(self, hit)) { + del(self, node) + if (!self[ALLOW_STALE]) + return undefined + } else { + if (doUse) { + if (self[UPDATE_AGE_ON_GET]) + node.value.now = Date.now() + self[LRU_LIST].unshiftNode(node) + } + } + return hit.value + } +} + +const isStale = (self, hit) => { + if (!hit || (!hit.maxAge && !self[MAX_AGE])) + return false + + const diff = Date.now() - hit.now + return hit.maxAge ? diff > hit.maxAge + : self[MAX_AGE] && (diff > self[MAX_AGE]) +} + +const trim = self => { + if (self[LENGTH] > self[MAX]) { + for (let walker = self[LRU_LIST].tail; + self[LENGTH] > self[MAX] && walker !== null;) { + // We know that we're about to delete this one, and also + // what the next least recently used key will be, so just + // go ahead and set it now. + const prev = walker.prev + del(self, walker) + walker = prev + } + } +} + +const del = (self, node) => { + if (node) { + const hit = node.value + if (self[DISPOSE]) + self[DISPOSE](hit.key, hit.value) + + self[LENGTH] -= hit.length + self[CACHE].delete(hit.key) + self[LRU_LIST].removeNode(node) + } +} + +class Entry { + constructor (key, value, length, now, maxAge) { + this.key = key + this.value = value + this.length = length + this.now = now + this.maxAge = maxAge || 0 + } +} + +const forEachStep = (self, fn, node, thisp) => { + let hit = node.value + if (isStale(self, hit)) { + del(self, node) + if (!self[ALLOW_STALE]) + hit = undefined + } + if (hit) + fn.call(thisp, hit.value, hit.key, self) +} + +module.exports = LRUCache |