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-rw-r--r--lib/pool-base.js194
1 files changed, 194 insertions, 0 deletions
diff --git a/lib/pool-base.js b/lib/pool-base.js
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index 0000000..2a909ee
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+++ b/lib/pool-base.js
@@ -0,0 +1,194 @@
+'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
+}