lib: refactor internal/socket_list

PR-URL: https://github.com/nodejs/node/pull/11406
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

lib/internal/socket_list.js

@@ -1,104 +1,105 @@
 'use strict';
 
-module.exports = {SocketListSend, SocketListReceive};
-
 const EventEmitter = require('events');
-const util = require('util');
 
 // This object keep track of the socket there are sended
-function SocketListSend(slave, key) {
-  EventEmitter.call(this);
+class SocketListSend extends EventEmitter {
+  constructor(child, key) {
+    super();
+    this.key = key;
+    this.child = child;
+  }
 
-  this.key = key;
-  this.slave = slave;
-}
-util.inherits(SocketListSend, EventEmitter);
+  _request(msg, cmd, callback) {
+    var self = this;
+
+    if (!this.child.connected) return onclose();
+    this.child.send(msg);
 
-SocketListSend.prototype._request = function(msg, cmd, callback) {
-  var self = this;
+    function onclose() {
+      self.child.removeListener('internalMessage', onreply);
+      callback(new Error('child closed before reply'));
+    }
 
-  if (!this.slave.connected) return onclose();
-  this.slave.send(msg);
+    function onreply(msg) {
+      if (!(msg.cmd === cmd && msg.key === self.key)) return;
+      self.child.removeListener('disconnect', onclose);
+      self.child.removeListener('internalMessage', onreply);
 
-  function onclose() {
-    self.slave.removeListener('internalMessage', onreply);
-    callback(new Error('Slave closed before reply'));
+      callback(null, msg);
+    }
+
+    this.child.once('disconnect', onclose);
+    this.child.on('internalMessage', onreply);
   }
 
-  function onreply(msg) {
-    if (!(msg.cmd === cmd && msg.key === self.key)) return;
-    self.slave.removeListener('disconnect', onclose);
-    self.slave.removeListener('internalMessage', onreply);
+  close(callback) {
+    this._request({
+      cmd: 'NODE_SOCKET_NOTIFY_CLOSE',
+      key: this.key
+    }, 'NODE_SOCKET_ALL_CLOSED', callback);
+  }
 
-    callback(null, msg);
+  getConnections(callback) {
+    this._request({
+      cmd: 'NODE_SOCKET_GET_COUNT',
+      key: this.key
+    }, 'NODE_SOCKET_COUNT', function(err, msg) {
+      if (err) return callback(err);
+      callback(null, msg.count);
+    });
   }
+}
 
-  this.slave.once('disconnect', onclose);
-  this.slave.on('internalMessage', onreply);
-};
-
-SocketListSend.prototype.close = function close(callback) {
-  this._request({
-    cmd: 'NODE_SOCKET_NOTIFY_CLOSE',
-    key: this.key
-  }, 'NODE_SOCKET_ALL_CLOSED', callback);
-};
-
-SocketListSend.prototype.getConnections = function getConnections(callback) {
-  this._request({
-    cmd: 'NODE_SOCKET_GET_COUNT',
-    key: this.key
-  }, 'NODE_SOCKET_COUNT', function(err, msg) {
-    if (err) return callback(err);
-    callback(null, msg.count);
-  });
-};
 
 // This object keep track of the socket there are received
-function SocketListReceive(slave, key) {
-  EventEmitter.call(this);
+class SocketListReceive extends EventEmitter {
+  constructor(child, key) {
+    super();
 
-  this.connections = 0;
-  this.key = key;
-  this.slave = slave;
+    this.connections = 0;
+    this.key = key;
+    this.child = child;
 
-  function onempty(self) {
-    if (!self.slave.connected) return;
+    function onempty(self) {
+      if (!self.child.connected) return;
 
-    self.slave.send({
-      cmd: 'NODE_SOCKET_ALL_CLOSED',
-      key: self.key
+      self.child.send({
+        cmd: 'NODE_SOCKET_ALL_CLOSED',
+        key: self.key
+      });
+    }
+
+    this.child.on('internalMessage', (msg) => {
+      if (msg.key !== this.key) return;
+
+      if (msg.cmd === 'NODE_SOCKET_NOTIFY_CLOSE') {
+        // Already empty
+        if (this.connections === 0) return onempty(this);
+
+        // Wait for sockets to get closed
+        this.once('empty', onempty);
+      } else if (msg.cmd === 'NODE_SOCKET_GET_COUNT') {
+        if (!this.child.connected) return;
+        this.child.send({
+          cmd: 'NODE_SOCKET_COUNT',
+          key: this.key,
+          count: this.connections
+        });
+      }
     });
   }
 
-  this.slave.on('internalMessage', (msg) => {
-    if (msg.key !== this.key) return;
-
-    if (msg.cmd === 'NODE_SOCKET_NOTIFY_CLOSE') {
-      // Already empty
-      if (this.connections === 0) return onempty(this);
-
-      // Wait for sockets to get closed
-      this.once('empty', onempty);
-    } else if (msg.cmd === 'NODE_SOCKET_GET_COUNT') {
-      if (!this.slave.connected) return;
-      this.slave.send({
-        cmd: 'NODE_SOCKET_COUNT',
-        key: this.key,
-        count: this.connections
-      });
-    }
-  });
-}
-util.inherits(SocketListReceive, EventEmitter);
+  add(obj) {
+    this.connections++;
 
-SocketListReceive.prototype.add = function(obj) {
-  this.connections++;
+    // Notify previous owner of socket about its state change
+    obj.socket.once('close', () => {
+      this.connections--;
 
-  // Notify previous owner of socket about its state change
-  obj.socket.once('close', () => {
-    this.connections--;
+      if (this.connections === 0) this.emit('empty', this);
+    });
+  }
+}
 
-    if (this.connections === 0) this.emit('empty', this);
-  });
-};
+module.exports = {SocketListSend, SocketListReceive};