forked from zhurui/management
335 lines
8.0 KiB
JavaScript
335 lines
8.0 KiB
JavaScript
;(function () { // closure for web browsers
|
|
|
|
if (typeof module === 'object' && module.exports) {
|
|
module.exports = LRUCache
|
|
} else {
|
|
// just set the global for non-node platforms.
|
|
this.LRUCache = LRUCache
|
|
}
|
|
|
|
function hOP (obj, key) {
|
|
return Object.prototype.hasOwnProperty.call(obj, key)
|
|
}
|
|
|
|
function naiveLength () { return 1 }
|
|
|
|
var didTypeWarning = false
|
|
function typeCheckKey(key) {
|
|
if (!didTypeWarning && typeof key !== 'string' && typeof key !== 'number') {
|
|
didTypeWarning = true
|
|
console.error(new TypeError("LRU: key must be a string or number. Almost certainly a bug! " + typeof key).stack)
|
|
}
|
|
}
|
|
|
|
function LRUCache (options) {
|
|
if (!(this instanceof LRUCache))
|
|
return new LRUCache(options)
|
|
|
|
if (typeof options === 'number')
|
|
options = { max: options }
|
|
|
|
if (!options)
|
|
options = {}
|
|
|
|
this._max = options.max
|
|
// Kind of weird to have a default max of Infinity, but oh well.
|
|
if (!this._max || !(typeof this._max === "number") || this._max <= 0 )
|
|
this._max = Infinity
|
|
|
|
this._lengthCalculator = options.length || naiveLength
|
|
if (typeof this._lengthCalculator !== "function")
|
|
this._lengthCalculator = naiveLength
|
|
|
|
this._allowStale = options.stale || false
|
|
this._maxAge = options.maxAge || null
|
|
this._dispose = options.dispose
|
|
this.reset()
|
|
}
|
|
|
|
// resize the cache when the max changes.
|
|
Object.defineProperty(LRUCache.prototype, "max",
|
|
{ set : function (mL) {
|
|
if (!mL || !(typeof mL === "number") || mL <= 0 ) mL = Infinity
|
|
this._max = mL
|
|
if (this._length > this._max) trim(this)
|
|
}
|
|
, get : function () { return this._max }
|
|
, enumerable : true
|
|
})
|
|
|
|
// resize the cache when the lengthCalculator changes.
|
|
Object.defineProperty(LRUCache.prototype, "lengthCalculator",
|
|
{ set : function (lC) {
|
|
if (typeof lC !== "function") {
|
|
this._lengthCalculator = naiveLength
|
|
this._length = this._itemCount
|
|
for (var key in this._cache) {
|
|
this._cache[key].length = 1
|
|
}
|
|
} else {
|
|
this._lengthCalculator = lC
|
|
this._length = 0
|
|
for (var key in this._cache) {
|
|
this._cache[key].length = this._lengthCalculator(this._cache[key].value)
|
|
this._length += this._cache[key].length
|
|
}
|
|
}
|
|
|
|
if (this._length > this._max) trim(this)
|
|
}
|
|
, get : function () { return this._lengthCalculator }
|
|
, enumerable : true
|
|
})
|
|
|
|
Object.defineProperty(LRUCache.prototype, "length",
|
|
{ get : function () { return this._length }
|
|
, enumerable : true
|
|
})
|
|
|
|
|
|
Object.defineProperty(LRUCache.prototype, "itemCount",
|
|
{ get : function () { return this._itemCount }
|
|
, enumerable : true
|
|
})
|
|
|
|
LRUCache.prototype.forEach = function (fn, thisp) {
|
|
thisp = thisp || this
|
|
var i = 0
|
|
var itemCount = this._itemCount
|
|
|
|
for (var k = this._mru - 1; k >= 0 && i < itemCount; k--) if (this._lruList[k]) {
|
|
i++
|
|
var hit = this._lruList[k]
|
|
if (isStale(this, hit)) {
|
|
del(this, hit)
|
|
if (!this._allowStale) hit = undefined
|
|
}
|
|
if (hit) {
|
|
fn.call(thisp, hit.value, hit.key, this)
|
|
}
|
|
}
|
|
}
|
|
|
|
LRUCache.prototype.keys = function () {
|
|
var keys = new Array(this._itemCount)
|
|
var i = 0
|
|
for (var k = this._mru - 1; k >= 0 && i < this._itemCount; k--) if (this._lruList[k]) {
|
|
var hit = this._lruList[k]
|
|
keys[i++] = hit.key
|
|
}
|
|
return keys
|
|
}
|
|
|
|
LRUCache.prototype.values = function () {
|
|
var values = new Array(this._itemCount)
|
|
var i = 0
|
|
for (var k = this._mru - 1; k >= 0 && i < this._itemCount; k--) if (this._lruList[k]) {
|
|
var hit = this._lruList[k]
|
|
values[i++] = hit.value
|
|
}
|
|
return values
|
|
}
|
|
|
|
LRUCache.prototype.reset = function () {
|
|
if (this._dispose && this._cache) {
|
|
for (var k in this._cache) {
|
|
this._dispose(k, this._cache[k].value)
|
|
}
|
|
}
|
|
|
|
this._cache = Object.create(null) // hash of items by key
|
|
this._lruList = Object.create(null) // list of items in order of use recency
|
|
this._mru = 0 // most recently used
|
|
this._lru = 0 // least recently used
|
|
this._length = 0 // number of items in the list
|
|
this._itemCount = 0
|
|
}
|
|
|
|
LRUCache.prototype.dump = function () {
|
|
var arr = []
|
|
var i = 0
|
|
|
|
for (var k = this._mru - 1; k >= 0 && i < this._itemCount; k--) if (this._lruList[k]) {
|
|
var hit = this._lruList[k]
|
|
if (!isStale(this, hit)) {
|
|
//Do not store staled hits
|
|
++i
|
|
arr.push({
|
|
k: hit.key,
|
|
v: hit.value,
|
|
e: hit.now + (hit.maxAge || 0)
|
|
});
|
|
}
|
|
}
|
|
//arr has the most read first
|
|
return arr
|
|
}
|
|
|
|
LRUCache.prototype.dumpLru = function () {
|
|
return this._lruList
|
|
}
|
|
|
|
LRUCache.prototype.set = function (key, value, maxAge) {
|
|
maxAge = maxAge || this._maxAge
|
|
typeCheckKey(key)
|
|
|
|
var now = maxAge ? Date.now() : 0
|
|
var len = this._lengthCalculator(value)
|
|
|
|
if (hOP(this._cache, key)) {
|
|
if (len > this._max) {
|
|
del(this, this._cache[key])
|
|
return false
|
|
}
|
|
// dispose of the old one before overwriting
|
|
if (this._dispose)
|
|
this._dispose(key, this._cache[key].value)
|
|
|
|
this._cache[key].now = now
|
|
this._cache[key].maxAge = maxAge
|
|
this._cache[key].value = value
|
|
this._length += (len - this._cache[key].length)
|
|
this._cache[key].length = len
|
|
this.get(key)
|
|
|
|
if (this._length > this._max)
|
|
trim(this)
|
|
|
|
return true
|
|
}
|
|
|
|
var hit = new Entry(key, value, this._mru++, 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._lruList[hit.lu] = this._cache[key] = hit
|
|
this._itemCount ++
|
|
|
|
if (this._length > this._max)
|
|
trim(this)
|
|
|
|
return true
|
|
}
|
|
|
|
LRUCache.prototype.has = function (key) {
|
|
typeCheckKey(key)
|
|
if (!hOP(this._cache, key)) return false
|
|
var hit = this._cache[key]
|
|
if (isStale(this, hit)) {
|
|
return false
|
|
}
|
|
return true
|
|
}
|
|
|
|
LRUCache.prototype.get = function (key) {
|
|
typeCheckKey(key)
|
|
return get(this, key, true)
|
|
}
|
|
|
|
LRUCache.prototype.peek = function (key) {
|
|
typeCheckKey(key)
|
|
return get(this, key, false)
|
|
}
|
|
|
|
LRUCache.prototype.pop = function () {
|
|
var hit = this._lruList[this._lru]
|
|
del(this, hit)
|
|
return hit || null
|
|
}
|
|
|
|
LRUCache.prototype.del = function (key) {
|
|
typeCheckKey(key)
|
|
del(this, this._cache[key])
|
|
}
|
|
|
|
LRUCache.prototype.load = function (arr) {
|
|
//reset the cache
|
|
this.reset();
|
|
|
|
var now = Date.now()
|
|
//A previous serialized cache has the most recent items first
|
|
for (var l = arr.length - 1; l >= 0; l-- ) {
|
|
var hit = arr[l]
|
|
typeCheckKey(hit.k)
|
|
var 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 {
|
|
var maxAge = expiresAt - now
|
|
//dont add already expired items
|
|
if (maxAge > 0) this.set(hit.k, hit.v, maxAge)
|
|
}
|
|
}
|
|
}
|
|
|
|
function get (self, key, doUse) {
|
|
typeCheckKey(key)
|
|
var hit = self._cache[key]
|
|
if (hit) {
|
|
if (isStale(self, hit)) {
|
|
del(self, hit)
|
|
if (!self._allowStale) hit = undefined
|
|
} else {
|
|
if (doUse) use(self, hit)
|
|
}
|
|
if (hit) hit = hit.value
|
|
}
|
|
return hit
|
|
}
|
|
|
|
function isStale(self, hit) {
|
|
if (!hit || (!hit.maxAge && !self._maxAge)) return false
|
|
var stale = false;
|
|
var diff = Date.now() - hit.now
|
|
if (hit.maxAge) {
|
|
stale = diff > hit.maxAge
|
|
} else {
|
|
stale = self._maxAge && (diff > self._maxAge)
|
|
}
|
|
return stale;
|
|
}
|
|
|
|
function use (self, hit) {
|
|
shiftLU(self, hit)
|
|
hit.lu = self._mru ++
|
|
self._lruList[hit.lu] = hit
|
|
}
|
|
|
|
function trim (self) {
|
|
while (self._lru < self._mru && self._length > self._max)
|
|
del(self, self._lruList[self._lru])
|
|
}
|
|
|
|
function shiftLU (self, hit) {
|
|
delete self._lruList[ hit.lu ]
|
|
while (self._lru < self._mru && !self._lruList[self._lru]) self._lru ++
|
|
}
|
|
|
|
function del (self, hit) {
|
|
if (hit) {
|
|
if (self._dispose) self._dispose(hit.key, hit.value)
|
|
self._length -= hit.length
|
|
self._itemCount --
|
|
delete self._cache[ hit.key ]
|
|
shiftLU(self, hit)
|
|
}
|
|
}
|
|
|
|
// classy, since V8 prefers predictable objects.
|
|
function Entry (key, value, lu, length, now, maxAge) {
|
|
this.key = key
|
|
this.value = value
|
|
this.lu = lu
|
|
this.length = length
|
|
this.now = now
|
|
if (maxAge) this.maxAge = maxAge
|
|
}
|
|
|
|
})()
|