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1228 lines
33 KiB
JavaScript
1228 lines
33 KiB
JavaScript
const perf =
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typeof performance === 'object' &&
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performance &&
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typeof performance.now === 'function'
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? performance
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: Date
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const hasAbortController = typeof AbortController === 'function'
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// minimal backwards-compatibility polyfill
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// this doesn't have nearly all the checks and whatnot that
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// actual AbortController/Signal has, but it's enough for
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// our purposes, and if used properly, behaves the same.
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const AC = hasAbortController
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? AbortController
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: class AbortController {
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constructor() {
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this.signal = new AS()
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}
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abort(reason = new Error('This operation was aborted')) {
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this.signal.reason = this.signal.reason || reason
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this.signal.aborted = true
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this.signal.dispatchEvent({
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type: 'abort',
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target: this.signal,
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})
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}
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}
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const hasAbortSignal = typeof AbortSignal === 'function'
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// Some polyfills put this on the AC class, not global
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const hasACAbortSignal = typeof AC.AbortSignal === 'function'
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const AS = hasAbortSignal
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? AbortSignal
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: hasACAbortSignal
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? AC.AbortController
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: class AbortSignal {
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constructor() {
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this.reason = undefined
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this.aborted = false
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this._listeners = []
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}
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dispatchEvent(e) {
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if (e.type === 'abort') {
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this.aborted = true
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this.onabort(e)
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this._listeners.forEach(f => f(e), this)
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}
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}
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onabort() {}
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addEventListener(ev, fn) {
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if (ev === 'abort') {
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this._listeners.push(fn)
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}
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}
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removeEventListener(ev, fn) {
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if (ev === 'abort') {
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this._listeners = this._listeners.filter(f => f !== fn)
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}
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}
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}
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const warned = new Set()
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const deprecatedOption = (opt, instead) => {
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const code = `LRU_CACHE_OPTION_${opt}`
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if (shouldWarn(code)) {
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warn(code, `${opt} option`, `options.${instead}`, LRUCache)
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}
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}
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const deprecatedMethod = (method, instead) => {
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const code = `LRU_CACHE_METHOD_${method}`
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if (shouldWarn(code)) {
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const { prototype } = LRUCache
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const { get } = Object.getOwnPropertyDescriptor(prototype, method)
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warn(code, `${method} method`, `cache.${instead}()`, get)
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}
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}
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const deprecatedProperty = (field, instead) => {
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const code = `LRU_CACHE_PROPERTY_${field}`
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if (shouldWarn(code)) {
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const { prototype } = LRUCache
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const { get } = Object.getOwnPropertyDescriptor(prototype, field)
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warn(code, `${field} property`, `cache.${instead}`, get)
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}
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}
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const emitWarning = (...a) => {
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typeof process === 'object' &&
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process &&
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typeof process.emitWarning === 'function'
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? process.emitWarning(...a)
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: console.error(...a)
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}
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const shouldWarn = code => !warned.has(code)
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const warn = (code, what, instead, fn) => {
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warned.add(code)
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const msg = `The ${what} is deprecated. Please use ${instead} instead.`
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emitWarning(msg, 'DeprecationWarning', code, fn)
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}
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const isPosInt = n => n && n === Math.floor(n) && n > 0 && isFinite(n)
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/* istanbul ignore next - This is a little bit ridiculous, tbh.
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* The maximum array length is 2^32-1 or thereabouts on most JS impls.
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* And well before that point, you're caching the entire world, I mean,
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* that's ~32GB of just integers for the next/prev links, plus whatever
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* else to hold that many keys and values. Just filling the memory with
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* zeroes at init time is brutal when you get that big.
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* But why not be complete?
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* Maybe in the future, these limits will have expanded. */
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const getUintArray = max =>
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!isPosInt(max)
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? null
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: max <= Math.pow(2, 8)
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? Uint8Array
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: max <= Math.pow(2, 16)
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? Uint16Array
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: max <= Math.pow(2, 32)
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? Uint32Array
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: max <= Number.MAX_SAFE_INTEGER
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? ZeroArray
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: null
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class ZeroArray extends Array {
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constructor(size) {
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super(size)
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this.fill(0)
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}
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}
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class Stack {
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constructor(max) {
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if (max === 0) {
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return []
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}
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const UintArray = getUintArray(max)
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this.heap = new UintArray(max)
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this.length = 0
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}
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push(n) {
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this.heap[this.length++] = n
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}
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pop() {
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return this.heap[--this.length]
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}
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}
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class LRUCache {
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constructor(options = {}) {
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const {
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max = 0,
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ttl,
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ttlResolution = 1,
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ttlAutopurge,
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updateAgeOnGet,
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updateAgeOnHas,
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allowStale,
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dispose,
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disposeAfter,
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noDisposeOnSet,
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noUpdateTTL,
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maxSize = 0,
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maxEntrySize = 0,
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sizeCalculation,
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fetchMethod,
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fetchContext,
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noDeleteOnFetchRejection,
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noDeleteOnStaleGet,
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allowStaleOnFetchRejection,
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allowStaleOnFetchAbort,
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ignoreFetchAbort,
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} = options
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// deprecated options, don't trigger a warning for getting them if
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// the thing being passed in is another LRUCache we're copying.
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const { length, maxAge, stale } =
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options instanceof LRUCache ? {} : options
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if (max !== 0 && !isPosInt(max)) {
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throw new TypeError('max option must be a nonnegative integer')
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}
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const UintArray = max ? getUintArray(max) : Array
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if (!UintArray) {
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throw new Error('invalid max value: ' + max)
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}
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this.max = max
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this.maxSize = maxSize
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this.maxEntrySize = maxEntrySize || this.maxSize
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this.sizeCalculation = sizeCalculation || length
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if (this.sizeCalculation) {
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if (!this.maxSize && !this.maxEntrySize) {
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throw new TypeError(
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'cannot set sizeCalculation without setting maxSize or maxEntrySize'
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)
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}
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if (typeof this.sizeCalculation !== 'function') {
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throw new TypeError('sizeCalculation set to non-function')
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}
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}
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this.fetchMethod = fetchMethod || null
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if (this.fetchMethod && typeof this.fetchMethod !== 'function') {
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throw new TypeError(
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'fetchMethod must be a function if specified'
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)
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}
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this.fetchContext = fetchContext
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if (!this.fetchMethod && fetchContext !== undefined) {
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throw new TypeError(
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'cannot set fetchContext without fetchMethod'
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)
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}
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this.keyMap = new Map()
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this.keyList = new Array(max).fill(null)
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this.valList = new Array(max).fill(null)
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this.next = new UintArray(max)
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this.prev = new UintArray(max)
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this.head = 0
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this.tail = 0
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this.free = new Stack(max)
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this.initialFill = 1
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this.size = 0
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if (typeof dispose === 'function') {
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this.dispose = dispose
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}
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if (typeof disposeAfter === 'function') {
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this.disposeAfter = disposeAfter
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this.disposed = []
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} else {
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this.disposeAfter = null
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this.disposed = null
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}
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this.noDisposeOnSet = !!noDisposeOnSet
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this.noUpdateTTL = !!noUpdateTTL
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this.noDeleteOnFetchRejection = !!noDeleteOnFetchRejection
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this.allowStaleOnFetchRejection = !!allowStaleOnFetchRejection
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this.allowStaleOnFetchAbort = !!allowStaleOnFetchAbort
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this.ignoreFetchAbort = !!ignoreFetchAbort
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// NB: maxEntrySize is set to maxSize if it's set
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if (this.maxEntrySize !== 0) {
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if (this.maxSize !== 0) {
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if (!isPosInt(this.maxSize)) {
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throw new TypeError(
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'maxSize must be a positive integer if specified'
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)
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}
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}
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if (!isPosInt(this.maxEntrySize)) {
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throw new TypeError(
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'maxEntrySize must be a positive integer if specified'
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)
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}
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this.initializeSizeTracking()
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}
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this.allowStale = !!allowStale || !!stale
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this.noDeleteOnStaleGet = !!noDeleteOnStaleGet
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this.updateAgeOnGet = !!updateAgeOnGet
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this.updateAgeOnHas = !!updateAgeOnHas
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this.ttlResolution =
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isPosInt(ttlResolution) || ttlResolution === 0
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? ttlResolution
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: 1
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this.ttlAutopurge = !!ttlAutopurge
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this.ttl = ttl || maxAge || 0
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if (this.ttl) {
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if (!isPosInt(this.ttl)) {
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throw new TypeError(
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'ttl must be a positive integer if specified'
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)
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}
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this.initializeTTLTracking()
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}
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|
|
// do not allow completely unbounded caches
|
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if (this.max === 0 && this.ttl === 0 && this.maxSize === 0) {
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throw new TypeError(
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'At least one of max, maxSize, or ttl is required'
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)
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}
|
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if (!this.ttlAutopurge && !this.max && !this.maxSize) {
|
|
const code = 'LRU_CACHE_UNBOUNDED'
|
|
if (shouldWarn(code)) {
|
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warned.add(code)
|
|
const msg =
|
|
'TTL caching without ttlAutopurge, max, or maxSize can ' +
|
|
'result in unbounded memory consumption.'
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emitWarning(msg, 'UnboundedCacheWarning', code, LRUCache)
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}
|
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}
|
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|
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if (stale) {
|
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deprecatedOption('stale', 'allowStale')
|
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}
|
|
if (maxAge) {
|
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deprecatedOption('maxAge', 'ttl')
|
|
}
|
|
if (length) {
|
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deprecatedOption('length', 'sizeCalculation')
|
|
}
|
|
}
|
|
|
|
getRemainingTTL(key) {
|
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return this.has(key, { updateAgeOnHas: false }) ? Infinity : 0
|
|
}
|
|
|
|
initializeTTLTracking() {
|
|
this.ttls = new ZeroArray(this.max)
|
|
this.starts = new ZeroArray(this.max)
|
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|
|
this.setItemTTL = (index, ttl, start = perf.now()) => {
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this.starts[index] = ttl !== 0 ? start : 0
|
|
this.ttls[index] = ttl
|
|
if (ttl !== 0 && this.ttlAutopurge) {
|
|
const t = setTimeout(() => {
|
|
if (this.isStale(index)) {
|
|
this.delete(this.keyList[index])
|
|
}
|
|
}, ttl + 1)
|
|
/* istanbul ignore else - unref() not supported on all platforms */
|
|
if (t.unref) {
|
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t.unref()
|
|
}
|
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}
|
|
}
|
|
|
|
this.updateItemAge = index => {
|
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this.starts[index] = this.ttls[index] !== 0 ? perf.now() : 0
|
|
}
|
|
|
|
this.statusTTL = (status, index) => {
|
|
if (status) {
|
|
status.ttl = this.ttls[index]
|
|
status.start = this.starts[index]
|
|
status.now = cachedNow || getNow()
|
|
status.remainingTTL = status.now + status.ttl - status.start
|
|
}
|
|
}
|
|
|
|
// debounce calls to perf.now() to 1s so we're not hitting
|
|
// that costly call repeatedly.
|
|
let cachedNow = 0
|
|
const getNow = () => {
|
|
const n = perf.now()
|
|
if (this.ttlResolution > 0) {
|
|
cachedNow = n
|
|
const t = setTimeout(
|
|
() => (cachedNow = 0),
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|
this.ttlResolution
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|
)
|
|
/* istanbul ignore else - not available on all platforms */
|
|
if (t.unref) {
|
|
t.unref()
|
|
}
|
|
}
|
|
return n
|
|
}
|
|
|
|
this.getRemainingTTL = key => {
|
|
const index = this.keyMap.get(key)
|
|
if (index === undefined) {
|
|
return 0
|
|
}
|
|
return this.ttls[index] === 0 || this.starts[index] === 0
|
|
? Infinity
|
|
: this.starts[index] +
|
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this.ttls[index] -
|
|
(cachedNow || getNow())
|
|
}
|
|
|
|
this.isStale = index => {
|
|
return (
|
|
this.ttls[index] !== 0 &&
|
|
this.starts[index] !== 0 &&
|
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(cachedNow || getNow()) - this.starts[index] >
|
|
this.ttls[index]
|
|
)
|
|
}
|
|
}
|
|
updateItemAge(_index) {}
|
|
statusTTL(_status, _index) {}
|
|
setItemTTL(_index, _ttl, _start) {}
|
|
isStale(_index) {
|
|
return false
|
|
}
|
|
|
|
initializeSizeTracking() {
|
|
this.calculatedSize = 0
|
|
this.sizes = new ZeroArray(this.max)
|
|
this.removeItemSize = index => {
|
|
this.calculatedSize -= this.sizes[index]
|
|
this.sizes[index] = 0
|
|
}
|
|
this.requireSize = (k, v, size, sizeCalculation) => {
|
|
// provisionally accept background fetches.
|
|
// actual value size will be checked when they return.
|
|
if (this.isBackgroundFetch(v)) {
|
|
return 0
|
|
}
|
|
if (!isPosInt(size)) {
|
|
if (sizeCalculation) {
|
|
if (typeof sizeCalculation !== 'function') {
|
|
throw new TypeError('sizeCalculation must be a function')
|
|
}
|
|
size = sizeCalculation(v, k)
|
|
if (!isPosInt(size)) {
|
|
throw new TypeError(
|
|
'sizeCalculation return invalid (expect positive integer)'
|
|
)
|
|
}
|
|
} else {
|
|
throw new TypeError(
|
|
'invalid size value (must be positive integer). ' +
|
|
'When maxSize or maxEntrySize is used, sizeCalculation or size ' +
|
|
'must be set.'
|
|
)
|
|
}
|
|
}
|
|
return size
|
|
}
|
|
this.addItemSize = (index, size, status) => {
|
|
this.sizes[index] = size
|
|
if (this.maxSize) {
|
|
const maxSize = this.maxSize - this.sizes[index]
|
|
while (this.calculatedSize > maxSize) {
|
|
this.evict(true)
|
|
}
|
|
}
|
|
this.calculatedSize += this.sizes[index]
|
|
if (status) {
|
|
status.entrySize = size
|
|
status.totalCalculatedSize = this.calculatedSize
|
|
}
|
|
}
|
|
}
|
|
removeItemSize(_index) {}
|
|
addItemSize(_index, _size) {}
|
|
requireSize(_k, _v, size, sizeCalculation) {
|
|
if (size || sizeCalculation) {
|
|
throw new TypeError(
|
|
'cannot set size without setting maxSize or maxEntrySize on cache'
|
|
)
|
|
}
|
|
}
|
|
|
|
*indexes({ allowStale = this.allowStale } = {}) {
|
|
if (this.size) {
|
|
for (let i = this.tail; true; ) {
|
|
if (!this.isValidIndex(i)) {
|
|
break
|
|
}
|
|
if (allowStale || !this.isStale(i)) {
|
|
yield i
|
|
}
|
|
if (i === this.head) {
|
|
break
|
|
} else {
|
|
i = this.prev[i]
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
*rindexes({ allowStale = this.allowStale } = {}) {
|
|
if (this.size) {
|
|
for (let i = this.head; true; ) {
|
|
if (!this.isValidIndex(i)) {
|
|
break
|
|
}
|
|
if (allowStale || !this.isStale(i)) {
|
|
yield i
|
|
}
|
|
if (i === this.tail) {
|
|
break
|
|
} else {
|
|
i = this.next[i]
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
isValidIndex(index) {
|
|
return (
|
|
index !== undefined &&
|
|
this.keyMap.get(this.keyList[index]) === index
|
|
)
|
|
}
|
|
|
|
*entries() {
|
|
for (const i of this.indexes()) {
|
|
if (
|
|
this.valList[i] !== undefined &&
|
|
this.keyList[i] !== undefined &&
|
|
!this.isBackgroundFetch(this.valList[i])
|
|
) {
|
|
yield [this.keyList[i], this.valList[i]]
|
|
}
|
|
}
|
|
}
|
|
*rentries() {
|
|
for (const i of this.rindexes()) {
|
|
if (
|
|
this.valList[i] !== undefined &&
|
|
this.keyList[i] !== undefined &&
|
|
!this.isBackgroundFetch(this.valList[i])
|
|
) {
|
|
yield [this.keyList[i], this.valList[i]]
|
|
}
|
|
}
|
|
}
|
|
|
|
*keys() {
|
|
for (const i of this.indexes()) {
|
|
if (
|
|
this.keyList[i] !== undefined &&
|
|
!this.isBackgroundFetch(this.valList[i])
|
|
) {
|
|
yield this.keyList[i]
|
|
}
|
|
}
|
|
}
|
|
*rkeys() {
|
|
for (const i of this.rindexes()) {
|
|
if (
|
|
this.keyList[i] !== undefined &&
|
|
!this.isBackgroundFetch(this.valList[i])
|
|
) {
|
|
yield this.keyList[i]
|
|
}
|
|
}
|
|
}
|
|
|
|
*values() {
|
|
for (const i of this.indexes()) {
|
|
if (
|
|
this.valList[i] !== undefined &&
|
|
!this.isBackgroundFetch(this.valList[i])
|
|
) {
|
|
yield this.valList[i]
|
|
}
|
|
}
|
|
}
|
|
*rvalues() {
|
|
for (const i of this.rindexes()) {
|
|
if (
|
|
this.valList[i] !== undefined &&
|
|
!this.isBackgroundFetch(this.valList[i])
|
|
) {
|
|
yield this.valList[i]
|
|
}
|
|
}
|
|
}
|
|
|
|
[Symbol.iterator]() {
|
|
return this.entries()
|
|
}
|
|
|
|
find(fn, getOptions) {
|
|
for (const i of this.indexes()) {
|
|
const v = this.valList[i]
|
|
const value = this.isBackgroundFetch(v)
|
|
? v.__staleWhileFetching
|
|
: v
|
|
if (value === undefined) continue
|
|
if (fn(value, this.keyList[i], this)) {
|
|
return this.get(this.keyList[i], getOptions)
|
|
}
|
|
}
|
|
}
|
|
|
|
forEach(fn, thisp = this) {
|
|
for (const i of this.indexes()) {
|
|
const v = this.valList[i]
|
|
const value = this.isBackgroundFetch(v)
|
|
? v.__staleWhileFetching
|
|
: v
|
|
if (value === undefined) continue
|
|
fn.call(thisp, value, this.keyList[i], this)
|
|
}
|
|
}
|
|
|
|
rforEach(fn, thisp = this) {
|
|
for (const i of this.rindexes()) {
|
|
const v = this.valList[i]
|
|
const value = this.isBackgroundFetch(v)
|
|
? v.__staleWhileFetching
|
|
: v
|
|
if (value === undefined) continue
|
|
fn.call(thisp, value, this.keyList[i], this)
|
|
}
|
|
}
|
|
|
|
get prune() {
|
|
deprecatedMethod('prune', 'purgeStale')
|
|
return this.purgeStale
|
|
}
|
|
|
|
purgeStale() {
|
|
let deleted = false
|
|
for (const i of this.rindexes({ allowStale: true })) {
|
|
if (this.isStale(i)) {
|
|
this.delete(this.keyList[i])
|
|
deleted = true
|
|
}
|
|
}
|
|
return deleted
|
|
}
|
|
|
|
dump() {
|
|
const arr = []
|
|
for (const i of this.indexes({ allowStale: true })) {
|
|
const key = this.keyList[i]
|
|
const v = this.valList[i]
|
|
const value = this.isBackgroundFetch(v)
|
|
? v.__staleWhileFetching
|
|
: v
|
|
if (value === undefined) continue
|
|
const entry = { value }
|
|
if (this.ttls) {
|
|
entry.ttl = this.ttls[i]
|
|
// always dump the start relative to a portable timestamp
|
|
// it's ok for this to be a bit slow, it's a rare operation.
|
|
const age = perf.now() - this.starts[i]
|
|
entry.start = Math.floor(Date.now() - age)
|
|
}
|
|
if (this.sizes) {
|
|
entry.size = this.sizes[i]
|
|
}
|
|
arr.unshift([key, entry])
|
|
}
|
|
return arr
|
|
}
|
|
|
|
load(arr) {
|
|
this.clear()
|
|
for (const [key, entry] of arr) {
|
|
if (entry.start) {
|
|
// entry.start is a portable timestamp, but we may be using
|
|
// node's performance.now(), so calculate the offset.
|
|
// it's ok for this to be a bit slow, it's a rare operation.
|
|
const age = Date.now() - entry.start
|
|
entry.start = perf.now() - age
|
|
}
|
|
this.set(key, entry.value, entry)
|
|
}
|
|
}
|
|
|
|
dispose(_v, _k, _reason) {}
|
|
|
|
set(
|
|
k,
|
|
v,
|
|
{
|
|
ttl = this.ttl,
|
|
start,
|
|
noDisposeOnSet = this.noDisposeOnSet,
|
|
size = 0,
|
|
sizeCalculation = this.sizeCalculation,
|
|
noUpdateTTL = this.noUpdateTTL,
|
|
status,
|
|
} = {}
|
|
) {
|
|
size = this.requireSize(k, v, size, sizeCalculation)
|
|
// if the item doesn't fit, don't do anything
|
|
// NB: maxEntrySize set to maxSize by default
|
|
if (this.maxEntrySize && size > this.maxEntrySize) {
|
|
if (status) {
|
|
status.set = 'miss'
|
|
status.maxEntrySizeExceeded = true
|
|
}
|
|
// have to delete, in case a background fetch is there already.
|
|
// in non-async cases, this is a no-op
|
|
this.delete(k)
|
|
return this
|
|
}
|
|
let index = this.size === 0 ? undefined : this.keyMap.get(k)
|
|
if (index === undefined) {
|
|
// addition
|
|
index = this.newIndex()
|
|
this.keyList[index] = k
|
|
this.valList[index] = v
|
|
this.keyMap.set(k, index)
|
|
this.next[this.tail] = index
|
|
this.prev[index] = this.tail
|
|
this.tail = index
|
|
this.size++
|
|
this.addItemSize(index, size, status)
|
|
if (status) {
|
|
status.set = 'add'
|
|
}
|
|
noUpdateTTL = false
|
|
} else {
|
|
// update
|
|
this.moveToTail(index)
|
|
const oldVal = this.valList[index]
|
|
if (v !== oldVal) {
|
|
if (this.isBackgroundFetch(oldVal)) {
|
|
oldVal.__abortController.abort(new Error('replaced'))
|
|
} else {
|
|
if (!noDisposeOnSet) {
|
|
this.dispose(oldVal, k, 'set')
|
|
if (this.disposeAfter) {
|
|
this.disposed.push([oldVal, k, 'set'])
|
|
}
|
|
}
|
|
}
|
|
this.removeItemSize(index)
|
|
this.valList[index] = v
|
|
this.addItemSize(index, size, status)
|
|
if (status) {
|
|
status.set = 'replace'
|
|
const oldValue =
|
|
oldVal && this.isBackgroundFetch(oldVal)
|
|
? oldVal.__staleWhileFetching
|
|
: oldVal
|
|
if (oldValue !== undefined) status.oldValue = oldValue
|
|
}
|
|
} else if (status) {
|
|
status.set = 'update'
|
|
}
|
|
}
|
|
if (ttl !== 0 && this.ttl === 0 && !this.ttls) {
|
|
this.initializeTTLTracking()
|
|
}
|
|
if (!noUpdateTTL) {
|
|
this.setItemTTL(index, ttl, start)
|
|
}
|
|
this.statusTTL(status, index)
|
|
if (this.disposeAfter) {
|
|
while (this.disposed.length) {
|
|
this.disposeAfter(...this.disposed.shift())
|
|
}
|
|
}
|
|
return this
|
|
}
|
|
|
|
newIndex() {
|
|
if (this.size === 0) {
|
|
return this.tail
|
|
}
|
|
if (this.size === this.max && this.max !== 0) {
|
|
return this.evict(false)
|
|
}
|
|
if (this.free.length !== 0) {
|
|
return this.free.pop()
|
|
}
|
|
// initial fill, just keep writing down the list
|
|
return this.initialFill++
|
|
}
|
|
|
|
pop() {
|
|
if (this.size) {
|
|
const val = this.valList[this.head]
|
|
this.evict(true)
|
|
return val
|
|
}
|
|
}
|
|
|
|
evict(free) {
|
|
const head = this.head
|
|
const k = this.keyList[head]
|
|
const v = this.valList[head]
|
|
if (this.isBackgroundFetch(v)) {
|
|
v.__abortController.abort(new Error('evicted'))
|
|
} else {
|
|
this.dispose(v, k, 'evict')
|
|
if (this.disposeAfter) {
|
|
this.disposed.push([v, k, 'evict'])
|
|
}
|
|
}
|
|
this.removeItemSize(head)
|
|
// if we aren't about to use the index, then null these out
|
|
if (free) {
|
|
this.keyList[head] = null
|
|
this.valList[head] = null
|
|
this.free.push(head)
|
|
}
|
|
this.head = this.next[head]
|
|
this.keyMap.delete(k)
|
|
this.size--
|
|
return head
|
|
}
|
|
|
|
has(k, { updateAgeOnHas = this.updateAgeOnHas, status } = {}) {
|
|
const index = this.keyMap.get(k)
|
|
if (index !== undefined) {
|
|
if (!this.isStale(index)) {
|
|
if (updateAgeOnHas) {
|
|
this.updateItemAge(index)
|
|
}
|
|
if (status) status.has = 'hit'
|
|
this.statusTTL(status, index)
|
|
return true
|
|
} else if (status) {
|
|
status.has = 'stale'
|
|
this.statusTTL(status, index)
|
|
}
|
|
} else if (status) {
|
|
status.has = 'miss'
|
|
}
|
|
return false
|
|
}
|
|
|
|
// like get(), but without any LRU updating or TTL expiration
|
|
peek(k, { allowStale = this.allowStale } = {}) {
|
|
const index = this.keyMap.get(k)
|
|
if (index !== undefined && (allowStale || !this.isStale(index))) {
|
|
const v = this.valList[index]
|
|
// either stale and allowed, or forcing a refresh of non-stale value
|
|
return this.isBackgroundFetch(v) ? v.__staleWhileFetching : v
|
|
}
|
|
}
|
|
|
|
backgroundFetch(k, index, options, context) {
|
|
const v = index === undefined ? undefined : this.valList[index]
|
|
if (this.isBackgroundFetch(v)) {
|
|
return v
|
|
}
|
|
const ac = new AC()
|
|
if (options.signal) {
|
|
options.signal.addEventListener('abort', () =>
|
|
ac.abort(options.signal.reason)
|
|
)
|
|
}
|
|
const fetchOpts = {
|
|
signal: ac.signal,
|
|
options,
|
|
context,
|
|
}
|
|
const cb = (v, updateCache = false) => {
|
|
const { aborted } = ac.signal
|
|
const ignoreAbort = options.ignoreFetchAbort && v !== undefined
|
|
if (options.status) {
|
|
if (aborted && !updateCache) {
|
|
options.status.fetchAborted = true
|
|
options.status.fetchError = ac.signal.reason
|
|
if (ignoreAbort) options.status.fetchAbortIgnored = true
|
|
} else {
|
|
options.status.fetchResolved = true
|
|
}
|
|
}
|
|
if (aborted && !ignoreAbort && !updateCache) {
|
|
return fetchFail(ac.signal.reason)
|
|
}
|
|
// either we didn't abort, and are still here, or we did, and ignored
|
|
if (this.valList[index] === p) {
|
|
if (v === undefined) {
|
|
if (p.__staleWhileFetching) {
|
|
this.valList[index] = p.__staleWhileFetching
|
|
} else {
|
|
this.delete(k)
|
|
}
|
|
} else {
|
|
if (options.status) options.status.fetchUpdated = true
|
|
this.set(k, v, fetchOpts.options)
|
|
}
|
|
}
|
|
return v
|
|
}
|
|
const eb = er => {
|
|
if (options.status) {
|
|
options.status.fetchRejected = true
|
|
options.status.fetchError = er
|
|
}
|
|
return fetchFail(er)
|
|
}
|
|
const fetchFail = er => {
|
|
const { aborted } = ac.signal
|
|
const allowStaleAborted =
|
|
aborted && options.allowStaleOnFetchAbort
|
|
const allowStale =
|
|
allowStaleAborted || options.allowStaleOnFetchRejection
|
|
const noDelete = allowStale || options.noDeleteOnFetchRejection
|
|
if (this.valList[index] === p) {
|
|
// if we allow stale on fetch rejections, then we need to ensure that
|
|
// the stale value is not removed from the cache when the fetch fails.
|
|
const del = !noDelete || p.__staleWhileFetching === undefined
|
|
if (del) {
|
|
this.delete(k)
|
|
} else if (!allowStaleAborted) {
|
|
// still replace the *promise* with the stale value,
|
|
// since we are done with the promise at this point.
|
|
// leave it untouched if we're still waiting for an
|
|
// aborted background fetch that hasn't yet returned.
|
|
this.valList[index] = p.__staleWhileFetching
|
|
}
|
|
}
|
|
if (allowStale) {
|
|
if (options.status && p.__staleWhileFetching !== undefined) {
|
|
options.status.returnedStale = true
|
|
}
|
|
return p.__staleWhileFetching
|
|
} else if (p.__returned === p) {
|
|
throw er
|
|
}
|
|
}
|
|
const pcall = (res, rej) => {
|
|
this.fetchMethod(k, v, fetchOpts).then(v => res(v), rej)
|
|
// ignored, we go until we finish, regardless.
|
|
// defer check until we are actually aborting,
|
|
// so fetchMethod can override.
|
|
ac.signal.addEventListener('abort', () => {
|
|
if (
|
|
!options.ignoreFetchAbort ||
|
|
options.allowStaleOnFetchAbort
|
|
) {
|
|
res()
|
|
// when it eventually resolves, update the cache.
|
|
if (options.allowStaleOnFetchAbort) {
|
|
res = v => cb(v, true)
|
|
}
|
|
}
|
|
})
|
|
}
|
|
if (options.status) options.status.fetchDispatched = true
|
|
const p = new Promise(pcall).then(cb, eb)
|
|
p.__abortController = ac
|
|
p.__staleWhileFetching = v
|
|
p.__returned = null
|
|
if (index === undefined) {
|
|
// internal, don't expose status.
|
|
this.set(k, p, { ...fetchOpts.options, status: undefined })
|
|
index = this.keyMap.get(k)
|
|
} else {
|
|
this.valList[index] = p
|
|
}
|
|
return p
|
|
}
|
|
|
|
isBackgroundFetch(p) {
|
|
return (
|
|
p &&
|
|
typeof p === 'object' &&
|
|
typeof p.then === 'function' &&
|
|
Object.prototype.hasOwnProperty.call(
|
|
p,
|
|
'__staleWhileFetching'
|
|
) &&
|
|
Object.prototype.hasOwnProperty.call(p, '__returned') &&
|
|
(p.__returned === p || p.__returned === null)
|
|
)
|
|
}
|
|
|
|
// this takes the union of get() and set() opts, because it does both
|
|
async fetch(
|
|
k,
|
|
{
|
|
// get options
|
|
allowStale = this.allowStale,
|
|
updateAgeOnGet = this.updateAgeOnGet,
|
|
noDeleteOnStaleGet = this.noDeleteOnStaleGet,
|
|
// set options
|
|
ttl = this.ttl,
|
|
noDisposeOnSet = this.noDisposeOnSet,
|
|
size = 0,
|
|
sizeCalculation = this.sizeCalculation,
|
|
noUpdateTTL = this.noUpdateTTL,
|
|
// fetch exclusive options
|
|
noDeleteOnFetchRejection = this.noDeleteOnFetchRejection,
|
|
allowStaleOnFetchRejection = this.allowStaleOnFetchRejection,
|
|
ignoreFetchAbort = this.ignoreFetchAbort,
|
|
allowStaleOnFetchAbort = this.allowStaleOnFetchAbort,
|
|
fetchContext = this.fetchContext,
|
|
forceRefresh = false,
|
|
status,
|
|
signal,
|
|
} = {}
|
|
) {
|
|
if (!this.fetchMethod) {
|
|
if (status) status.fetch = 'get'
|
|
return this.get(k, {
|
|
allowStale,
|
|
updateAgeOnGet,
|
|
noDeleteOnStaleGet,
|
|
status,
|
|
})
|
|
}
|
|
|
|
const options = {
|
|
allowStale,
|
|
updateAgeOnGet,
|
|
noDeleteOnStaleGet,
|
|
ttl,
|
|
noDisposeOnSet,
|
|
size,
|
|
sizeCalculation,
|
|
noUpdateTTL,
|
|
noDeleteOnFetchRejection,
|
|
allowStaleOnFetchRejection,
|
|
allowStaleOnFetchAbort,
|
|
ignoreFetchAbort,
|
|
status,
|
|
signal,
|
|
}
|
|
|
|
let index = this.keyMap.get(k)
|
|
if (index === undefined) {
|
|
if (status) status.fetch = 'miss'
|
|
const p = this.backgroundFetch(k, index, options, fetchContext)
|
|
return (p.__returned = p)
|
|
} else {
|
|
// in cache, maybe already fetching
|
|
const v = this.valList[index]
|
|
if (this.isBackgroundFetch(v)) {
|
|
const stale =
|
|
allowStale && v.__staleWhileFetching !== undefined
|
|
if (status) {
|
|
status.fetch = 'inflight'
|
|
if (stale) status.returnedStale = true
|
|
}
|
|
return stale ? v.__staleWhileFetching : (v.__returned = v)
|
|
}
|
|
|
|
// if we force a refresh, that means do NOT serve the cached value,
|
|
// unless we are already in the process of refreshing the cache.
|
|
const isStale = this.isStale(index)
|
|
if (!forceRefresh && !isStale) {
|
|
if (status) status.fetch = 'hit'
|
|
this.moveToTail(index)
|
|
if (updateAgeOnGet) {
|
|
this.updateItemAge(index)
|
|
}
|
|
this.statusTTL(status, index)
|
|
return v
|
|
}
|
|
|
|
// ok, it is stale or a forced refresh, and not already fetching.
|
|
// refresh the cache.
|
|
const p = this.backgroundFetch(k, index, options, fetchContext)
|
|
const hasStale = p.__staleWhileFetching !== undefined
|
|
const staleVal = hasStale && allowStale
|
|
if (status) {
|
|
status.fetch = hasStale && isStale ? 'stale' : 'refresh'
|
|
if (staleVal && isStale) status.returnedStale = true
|
|
}
|
|
return staleVal ? p.__staleWhileFetching : (p.__returned = p)
|
|
}
|
|
}
|
|
|
|
get(
|
|
k,
|
|
{
|
|
allowStale = this.allowStale,
|
|
updateAgeOnGet = this.updateAgeOnGet,
|
|
noDeleteOnStaleGet = this.noDeleteOnStaleGet,
|
|
status,
|
|
} = {}
|
|
) {
|
|
const index = this.keyMap.get(k)
|
|
if (index !== undefined) {
|
|
const value = this.valList[index]
|
|
const fetching = this.isBackgroundFetch(value)
|
|
this.statusTTL(status, index)
|
|
if (this.isStale(index)) {
|
|
if (status) status.get = 'stale'
|
|
// delete only if not an in-flight background fetch
|
|
if (!fetching) {
|
|
if (!noDeleteOnStaleGet) {
|
|
this.delete(k)
|
|
}
|
|
if (status) status.returnedStale = allowStale
|
|
return allowStale ? value : undefined
|
|
} else {
|
|
if (status) {
|
|
status.returnedStale =
|
|
allowStale && value.__staleWhileFetching !== undefined
|
|
}
|
|
return allowStale ? value.__staleWhileFetching : undefined
|
|
}
|
|
} else {
|
|
if (status) status.get = 'hit'
|
|
// if we're currently fetching it, we don't actually have it yet
|
|
// it's not stale, which means this isn't a staleWhileRefetching.
|
|
// If it's not stale, and fetching, AND has a __staleWhileFetching
|
|
// value, then that means the user fetched with {forceRefresh:true},
|
|
// so it's safe to return that value.
|
|
if (fetching) {
|
|
return value.__staleWhileFetching
|
|
}
|
|
this.moveToTail(index)
|
|
if (updateAgeOnGet) {
|
|
this.updateItemAge(index)
|
|
}
|
|
return value
|
|
}
|
|
} else if (status) {
|
|
status.get = 'miss'
|
|
}
|
|
}
|
|
|
|
connect(p, n) {
|
|
this.prev[n] = p
|
|
this.next[p] = n
|
|
}
|
|
|
|
moveToTail(index) {
|
|
// if tail already, nothing to do
|
|
// if head, move head to next[index]
|
|
// else
|
|
// move next[prev[index]] to next[index] (head has no prev)
|
|
// move prev[next[index]] to prev[index]
|
|
// prev[index] = tail
|
|
// next[tail] = index
|
|
// tail = index
|
|
if (index !== this.tail) {
|
|
if (index === this.head) {
|
|
this.head = this.next[index]
|
|
} else {
|
|
this.connect(this.prev[index], this.next[index])
|
|
}
|
|
this.connect(this.tail, index)
|
|
this.tail = index
|
|
}
|
|
}
|
|
|
|
get del() {
|
|
deprecatedMethod('del', 'delete')
|
|
return this.delete
|
|
}
|
|
|
|
delete(k) {
|
|
let deleted = false
|
|
if (this.size !== 0) {
|
|
const index = this.keyMap.get(k)
|
|
if (index !== undefined) {
|
|
deleted = true
|
|
if (this.size === 1) {
|
|
this.clear()
|
|
} else {
|
|
this.removeItemSize(index)
|
|
const v = this.valList[index]
|
|
if (this.isBackgroundFetch(v)) {
|
|
v.__abortController.abort(new Error('deleted'))
|
|
} else {
|
|
this.dispose(v, k, 'delete')
|
|
if (this.disposeAfter) {
|
|
this.disposed.push([v, k, 'delete'])
|
|
}
|
|
}
|
|
this.keyMap.delete(k)
|
|
this.keyList[index] = null
|
|
this.valList[index] = null
|
|
if (index === this.tail) {
|
|
this.tail = this.prev[index]
|
|
} else if (index === this.head) {
|
|
this.head = this.next[index]
|
|
} else {
|
|
this.next[this.prev[index]] = this.next[index]
|
|
this.prev[this.next[index]] = this.prev[index]
|
|
}
|
|
this.size--
|
|
this.free.push(index)
|
|
}
|
|
}
|
|
}
|
|
if (this.disposed) {
|
|
while (this.disposed.length) {
|
|
this.disposeAfter(...this.disposed.shift())
|
|
}
|
|
}
|
|
return deleted
|
|
}
|
|
|
|
clear() {
|
|
for (const index of this.rindexes({ allowStale: true })) {
|
|
const v = this.valList[index]
|
|
if (this.isBackgroundFetch(v)) {
|
|
v.__abortController.abort(new Error('deleted'))
|
|
} else {
|
|
const k = this.keyList[index]
|
|
this.dispose(v, k, 'delete')
|
|
if (this.disposeAfter) {
|
|
this.disposed.push([v, k, 'delete'])
|
|
}
|
|
}
|
|
}
|
|
|
|
this.keyMap.clear()
|
|
this.valList.fill(null)
|
|
this.keyList.fill(null)
|
|
if (this.ttls) {
|
|
this.ttls.fill(0)
|
|
this.starts.fill(0)
|
|
}
|
|
if (this.sizes) {
|
|
this.sizes.fill(0)
|
|
}
|
|
this.head = 0
|
|
this.tail = 0
|
|
this.initialFill = 1
|
|
this.free.length = 0
|
|
this.calculatedSize = 0
|
|
this.size = 0
|
|
if (this.disposed) {
|
|
while (this.disposed.length) {
|
|
this.disposeAfter(...this.disposed.shift())
|
|
}
|
|
}
|
|
}
|
|
|
|
get reset() {
|
|
deprecatedMethod('reset', 'clear')
|
|
return this.clear
|
|
}
|
|
|
|
get length() {
|
|
deprecatedProperty('length', 'size')
|
|
return this.size
|
|
}
|
|
|
|
static get AbortController() {
|
|
return AC
|
|
}
|
|
static get AbortSignal() {
|
|
return AS
|
|
}
|
|
}
|
|
|
|
module.exports = LRUCache
|