/* @flow */
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import { isRegExp, remove } from 'shared/util'
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import { getFirstComponentChild } from 'core/vdom/helpers/index'
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type CacheEntry = {
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name: ?string;
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tag: ?string;
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componentInstance: Component;
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};
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type CacheEntryMap = { [key: string]: ?CacheEntry };
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function getComponentName (opts: ?VNodeComponentOptions): ?string {
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return opts && (opts.Ctor.options.name || opts.tag)
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}
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function matches (pattern: string | RegExp | Array<string>, name: string): boolean {
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if (Array.isArray(pattern)) {
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return pattern.indexOf(name) > -1
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} else if (typeof pattern === 'string') {
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return pattern.split(',').indexOf(name) > -1
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} else if (isRegExp(pattern)) {
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return pattern.test(name)
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}
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/* istanbul ignore next */
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return false
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}
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function pruneCache (keepAliveInstance: any, filter: Function) {
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const { cache, keys, _vnode } = keepAliveInstance
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for (const key in cache) {
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const entry: ?CacheEntry = cache[key]
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if (entry) {
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const name: ?string = entry.name
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if (name && !filter(name)) {
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pruneCacheEntry(cache, key, keys, _vnode)
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}
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}
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}
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}
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function pruneCacheEntry (
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cache: CacheEntryMap,
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key: string,
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keys: Array<string>,
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current?: VNode
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) {
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const entry: ?CacheEntry = cache[key]
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if (entry && (!current || entry.tag !== current.tag)) {
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entry.componentInstance.$destroy()
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}
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cache[key] = null
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remove(keys, key)
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}
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const patternTypes: Array<Function> = [String, RegExp, Array]
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export default {
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name: 'keep-alive',
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abstract: true,
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props: {
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include: patternTypes,
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exclude: patternTypes,
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max: [String, Number]
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},
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methods: {
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cacheVNode() {
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const { cache, keys, vnodeToCache, keyToCache } = this
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if (vnodeToCache) {
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const { tag, componentInstance, componentOptions } = vnodeToCache
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cache[keyToCache] = {
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name: getComponentName(componentOptions),
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tag,
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componentInstance,
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}
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keys.push(keyToCache)
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// prune oldest entry
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if (this.max && keys.length > parseInt(this.max)) {
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pruneCacheEntry(cache, keys[0], keys, this._vnode)
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}
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this.vnodeToCache = null
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}
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}
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},
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created () {
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this.cache = Object.create(null)
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this.keys = []
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},
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destroyed () {
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for (const key in this.cache) {
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pruneCacheEntry(this.cache, key, this.keys)
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}
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},
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mounted () {
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this.cacheVNode()
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this.$watch('include', val => {
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pruneCache(this, name => matches(val, name))
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})
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this.$watch('exclude', val => {
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pruneCache(this, name => !matches(val, name))
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})
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},
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updated () {
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this.cacheVNode()
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},
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render () {
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const slot = this.$slots.default
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const vnode: VNode = getFirstComponentChild(slot)
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const componentOptions: ?VNodeComponentOptions = vnode && vnode.componentOptions
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if (componentOptions) {
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// check pattern
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const name: ?string = getComponentName(componentOptions)
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const { include, exclude } = this
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if (
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// not included
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(include && (!name || !matches(include, name))) ||
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// excluded
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(exclude && name && matches(exclude, name))
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) {
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return vnode
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}
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const { cache, keys } = this
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const key: ?string = vnode.key == null
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// same constructor may get registered as different local components
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// so cid alone is not enough (#3269)
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? componentOptions.Ctor.cid + (componentOptions.tag ? `::${componentOptions.tag}` : '')
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: vnode.key
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if (cache[key]) {
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vnode.componentInstance = cache[key].componentInstance
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// make current key freshest
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remove(keys, key)
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keys.push(key)
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} else {
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// delay setting the cache until update
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this.vnodeToCache = vnode
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this.keyToCache = key
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}
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vnode.data.keepAlive = true
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}
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return vnode || (slot && slot[0])
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}
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}
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