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'use strict'
const DispatcherBase = require('./dispatcher-base')
const FixedQueue = require('./node/fixed-queue')
const { kConnected, kSize, kRunning, kPending, kQueued, kBusy, kFree, kUrl, kClose, kDestroy, kDispatch } = require('./core/symbols')
const PoolStats = require('./pool-stats')
const kClients = Symbol('clients')
const kNeedDrain = Symbol('needDrain')
const kQueue = Symbol('queue')
const kClosedResolve = Symbol('closed resolve')
const kOnDrain = Symbol('onDrain')
const kOnConnect = Symbol('onConnect')
const kOnDisconnect = Symbol('onDisconnect')
const kOnConnectionError = Symbol('onConnectionError')
const kGetDispatcher = Symbol('get dispatcher')
const kAddClient = Symbol('add client')
const kRemoveClient = Symbol('remove client')
const kStats = Symbol('stats')
class PoolBase extends DispatcherBase {
constructor () {
super()
this[kQueue] = new FixedQueue()
this[kClients] = []
this[kQueued] = 0
const pool = this
this[kOnDrain] = function onDrain (origin, targets) {
const queue = pool[kQueue]
let needDrain = false
while (!needDrain) {
const item = queue.shift()
if (!item) {
break
}
pool[kQueued]--
needDrain = !this.dispatch(item.opts, item.handler)
}
this[kNeedDrain] = needDrain
if (!this[kNeedDrain] && pool[kNeedDrain]) {
pool[kNeedDrain] = false
pool.emit('drain', origin, [pool, ...targets])
}
if (pool[kClosedResolve] && queue.isEmpty()) {
Promise
.all(pool[kClients].map(c => c.close()))
.then(pool[kClosedResolve])
}
}
this[kOnConnect] = (origin, targets) => {
pool.emit('connect', origin, [pool, ...targets])
}
this[kOnDisconnect] = (origin, targets, err) => {
pool.emit('disconnect', origin, [pool, ...targets], err)
}
this[kOnConnectionError] = (origin, targets, err) => {
pool.emit('connectionError', origin, [pool, ...targets], err)
}
this[kStats] = new PoolStats(this)
}
get [kBusy] () {
return this[kNeedDrain]
}
get [kConnected] () {
return this[kClients].filter(client => client[kConnected]).length
}
get [kFree] () {
return this[kClients].filter(client => client[kConnected] && !client[kNeedDrain]).length
}
get [kPending] () {
let ret = this[kQueued]
for (const { [kPending]: pending } of this[kClients]) {
ret += pending
}
return ret
}
get [kRunning] () {
let ret = 0
for (const { [kRunning]: running } of this[kClients]) {
ret += running
}
return ret
}
get [kSize] () {
let ret = this[kQueued]
for (const { [kSize]: size } of this[kClients]) {
ret += size
}
return ret
}
get stats () {
return this[kStats]
}
async [kClose] () {
if (this[kQueue].isEmpty()) {
return Promise.all(this[kClients].map(c => c.close()))
} else {
return new Promise((resolve) => {
this[kClosedResolve] = resolve
})
}
}
async [kDestroy] (err) {
while (true) {
const item = this[kQueue].shift()
if (!item) {
break
}
item.handler.onError(err)
}
return Promise.all(this[kClients].map(c => c.destroy(err)))
}
[kDispatch] (opts, handler) {
const dispatcher = this[kGetDispatcher]()
if (!dispatcher) {
this[kNeedDrain] = true
this[kQueue].push({ opts, handler })
this[kQueued]++
} else if (!dispatcher.dispatch(opts, handler)) {
dispatcher[kNeedDrain] = true
this[kNeedDrain] = !this[kGetDispatcher]()
}
return !this[kNeedDrain]
}
[kAddClient] (client) {
client
.on('drain', this[kOnDrain])
.on('connect', this[kOnConnect])
.on('disconnect', this[kOnDisconnect])
.on('connectionError', this[kOnConnectionError])
this[kClients].push(client)
if (this[kNeedDrain]) {
process.nextTick(() => {
if (this[kNeedDrain]) {
this[kOnDrain](client[kUrl], [this, client])
}
})
}
return this
}
[kRemoveClient] (client) {
client.close(() => {
const idx = this[kClients].indexOf(client)
if (idx !== -1) {
this[kClients].splice(idx, 1)
}
})
this[kNeedDrain] = this[kClients].some(dispatcher => (
!dispatcher[kNeedDrain] &&
dispatcher.closed !== true &&
dispatcher.destroyed !== true
))
}
}
module.exports = {
PoolBase,
kClients,
kNeedDrain,
kAddClient,
kRemoveClient,
kGetDispatcher
}
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