FM / lru-cache

/var/www/greso.tech/server/nsm/node_modules/named-placeholders/node_modules/lru-cache/

/var/www/greso.tech/server/nsm/node_modules/named-placeholders/node_modules/lru-cache

Name	Size	Mode	Actions
index.d.ts	26485	0644	edit dl rm
index.js	33933	0644	edit dl rm
index.mjs	33931	0644	edit dl rm
LICENSE	775	0644	edit dl rm
package.json	2133	0644	edit dl rm
README.md	36667	0644	edit dl rm

Edit: /var/www/greso.tech/server/nsm/node_modules/named-placeholders/node_modules/lru-cache/index.js (33933B)

const perf =
  typeof performance === 'object' &&
  performance &&
  typeof performance.now === 'function'
    ? performance
    : Date

const hasAbortController = typeof AbortController === 'function'

// minimal backwards-compatibility polyfill
// this doesn't have nearly all the checks and whatnot that
// actual AbortController/Signal has, but it's enough for
// our purposes, and if used properly, behaves the same.
const AC = hasAbortController
  ? AbortController
  : class AbortController {
      constructor() {
        this.signal = new AS()
      }
      abort(reason = new Error('This operation was aborted')) {
        this.signal.reason = this.signal.reason || reason
        this.signal.aborted = true
        this.signal.dispatchEvent({
          type: 'abort',
          target: this.signal,
        })
      }
    }

const hasAbortSignal = typeof AbortSignal === 'function'
// Some polyfills put this on the AC class, not global
const hasACAbortSignal = typeof AC.AbortSignal === 'function'
const AS = hasAbortSignal
  ? AbortSignal
  : hasACAbortSignal
  ? AC.AbortController
  : class AbortSignal {
      constructor() {
        this.reason = undefined
        this.aborted = false
        this._listeners = []
      }
      dispatchEvent(e) {
        if (e.type === 'abort') {
          this.aborted = true
          this.onabort(e)
          this._listeners.forEach(f => f(e), this)
        }
      }
      onabort() {}
      addEventListener(ev, fn) {
        if (ev === 'abort') {
          this._listeners.push(fn)
        }
      }
      removeEventListener(ev, fn) {
        if (ev === 'abort') {
          this._listeners = this._listeners.filter(f => f !== fn)
        }
      }
    }

const warned = new Set()
const deprecatedOption = (opt, instead) => {
  const code = `LRU_CACHE_OPTION_${opt}`
  if (shouldWarn(code)) {
    warn(code, `${opt} option`, `options.${instead}`, LRUCache)
  }
}
const deprecatedMethod = (method, instead) => {
  const code = `LRU_CACHE_METHOD_${method}`
  if (shouldWarn(code)) {
    const { prototype } = LRUCache
    const { get } = Object.getOwnPropertyDescriptor(prototype, method)
    warn(code, `${method} method`, `cache.${instead}()`, get)
  }
}
const deprecatedProperty = (field, instead) => {
  const code = `LRU_CACHE_PROPERTY_${field}`
  if (shouldWarn(code)) {
    const { prototype } = LRUCache
    const { get } = Object.getOwnPropertyDescriptor(prototype, field)
    warn(code, `${field} property`, `cache.${instead}`, get)
  }
}

const emitWarning = (...a) => {
  typeof process === 'object' &&
  process &&
  typeof process.emitWarning === 'function'
    ? process.emitWarning(...a)
    : console.error(...a)
}

const shouldWarn = code => !warned.has(code)

const warn = (code, what, instead, fn) => {
  warned.add(code)
  const msg = `The ${what} is deprecated. Please use ${instead} instead.`
  emitWarning(msg, 'DeprecationWarning', code, fn)
}

const isPosInt = n => n && n === Math.floor(n) && n > 0 && isFinite(n)

/* istanbul ignore next - This is a little bit ridiculous, tbh.
 * The maximum array length is 2^32-1 or thereabouts on most JS impls.
 * And well before that point, you're caching the entire world, I mean,
 * that's ~32GB of just integers for the next/prev links, plus whatever
 * else to hold that many keys and values.  Just filling the memory with
 * zeroes at init time is brutal when you get that big.
 * But why not be complete?
 * Maybe in the future, these limits will have expanded. */
const getUintArray = max =>
  !isPosInt(max)
    ? null
    : max <= Math.pow(2, 8)
    ? Uint8Array
    : max <= Math.pow(2, 16)
    ? Uint16Array
    : max <= Math.pow(2, 32)
    ? Uint32Array
    : max <= Number.MAX_SAFE_INTEGER
    ? ZeroArray
    : null

class ZeroArray extends Array {
  constructor(size) {
    super(size)
    this.fill(0)
  }
}

class Stack {
  constructor(max) {
    if (max === 0) {
      return []
    }
    const UintArray = getUintArray(max)
    this.heap = new UintArray(max)
    this.length = 0
  }
  push(n) {
    this.heap[this.length++] = n
  }
  pop() {
    return this.heap[--this.length]
  }
}

class LRUCache {
  constructor(options = {}) {
    const {
      max = 0,
      ttl,
      ttlResolution = 1,
      ttlAutopurge,
      updateAgeOnGet,
      updateAgeOnHas,
      allowStale,
      dispose,
      disposeAfter,
      noDisposeOnSet,
      noUpdateTTL,
      maxSize = 0,
      maxEntrySize = 0,
      sizeCalculation,
      fetchMethod,
      fetchContext,
      noDeleteOnFetchRejection,
      noDeleteOnStaleGet,
      allowStaleOnFetchRejection,
      allowStaleOnFetchAbort,
      ignoreFetchAbort,
    } = options

// deprecated options, don't trigger a warning for getting them if
    // the thing being passed in is another LRUCache we're copying.
    const { length, maxAge, stale } =
      options instanceof LRUCache ? {} : options

if (max !== 0 && !isPosInt(max)) {
      throw new TypeError('max option must be a nonnegative integer')
    }

const UintArray = max ? getUintArray(max) : Array
    if (!UintArray) {
      throw new Error('invalid max value: ' + max)
    }

this.max = max
    this.maxSize = maxSize
    this.maxEntrySize = maxEntrySize || this.maxSize
    this.sizeCalculation = sizeCalculation || length
    if (this.sizeCalculation) {
      if (!this.maxSize && !this.maxEntrySize) {
        throw new TypeError(
          'cannot set sizeCalculation without setting maxSize or maxEntrySize'
        )
      }
      if (typeof this.sizeCalculation !== 'function') {
        throw new TypeError('sizeCalculation set to non-function')
      }
    }

this.fetchMethod = fetchMethod || null
    if (this.fetchMethod && typeof this.fetchMethod !== 'function') {
      throw new TypeError(
        'fetchMethod must be a function if specified'
      )
    }

this.fetchContext = fetchContext
    if (!this.fetchMethod && fetchContext !== undefined) {
      throw new TypeError(
        'cannot set fetchContext without fetchMethod'
      )
    }

this.keyMap = new Map()
    this.keyList = new Array(max).fill(null)
    this.valList = new Array(max).fill(null)
    this.next = new UintArray(max)
    this.prev = new UintArray(max)
    this.head = 0
    this.tail = 0
    this.free = new Stack(max)
    this.initialFill = 1
    this.size = 0

if (typeof dispose === 'function') {
      this.dispose = dispose
    }
    if (typeof disposeAfter === 'function') {
      this.disposeAfter = disposeAfter
      this.disposed = []
    } else {
      this.disposeAfter = null
      this.disposed = null
    }
    this.noDisposeOnSet = !!noDisposeOnSet
    this.noUpdateTTL = !!noUpdateTTL
    this.noDeleteOnFetchRejection = !!noDeleteOnFetchRejection
    this.allowStaleOnFetchRejection = !!allowStaleOnFetchRejection
    this.allowStaleOnFetchAbort = !!allowStaleOnFetchAbort
    this.ignoreFetchAbort = !!ignoreFetchAbort

// NB: maxEntrySize is set to maxSize if it's set
    if (this.maxEntrySize !== 0) {
      if (this.maxSize !== 0) {
        if (!isPosInt(this.maxSize)) {
          throw new TypeError(
            'maxSize must be a positive integer if specified'
          )
        }
      }
      if (!isPosInt(this.maxEntrySize)) {
        throw new TypeError(
          'maxEntrySize must be a positive integer if specified'
        )
      }
      this.initializeSizeTracking()
    }

this.allowStale = !!allowStale || !!stale
    this.noDeleteOnStaleGet = !!noDeleteOnStaleGet
    this.updateAgeOnGet = !!updateAgeOnGet
    this.updateAgeOnHas = !!updateAgeOnHas
    this.ttlResolution =
      isPosInt(ttlResolution) || ttlResolution === 0
        ? ttlResolution
        : 1
    this.ttlAutopurge = !!ttlAutopurge
    this.ttl = ttl || maxAge || 0
    if (this.ttl) {
      if (!isPosInt(this.ttl)) {
        throw new TypeError(
          'ttl must be a positive integer if specified'
        )
      }
      this.initializeTTLTracking()
    }

// do not allow completely unbounded caches
    if (this.max === 0 && this.ttl === 0 && this.maxSize === 0) {
      throw new TypeError(
        'At least one of max, maxSize, or ttl is required'
      )
    }
    if (!this.ttlAutopurge && !this.max && !this.maxSize) {
      const code = 'LRU_CACHE_UNBOUNDED'
      if (shouldWarn(code)) {
        warned.add(code)
        const msg =
          'TTL caching without ttlAutopurge, max, or maxSize can ' +
          'result in unbounded memory consumption.'
        emitWarning(msg, 'UnboundedCacheWarning', code, LRUCache)
      }
    }

if (stale) {
      deprecatedOption('stale', 'allowStale')
    }
    if (maxAge) {
      deprecatedOption('maxAge', 'ttl')
    }
    if (length) {
      deprecatedOption('length', 'sizeCalculation')
    }
  }

getRemainingTTL(key) {
    return this.has(key, { updateAgeOnHas: false }) ? Infinity : 0
  }

initializeTTLTracking() {
    this.ttls = new ZeroArray(this.max)
    this.starts = new ZeroArray(this.max)

this.setItemTTL = (index, ttl, start = perf.now()) => {
      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) {
          t.unref()
        }
      }
    }

this.updateItemAge = index => {
      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),
          this.ttlResolution
        )
        /* 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] +
            this.ttls[index] -
            (cachedNow || getNow())
    }

this.isStale = index => {
      return (
        this.ttls[index] !== 0 &&
        this.starts[index] !== 0 &&
        (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

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