refactor(mongos): support passing callback to destroy

Author: mbroadst

lib/topologies/mongos.js

@@ -254,10 +254,10 @@ function emitSDAMEvent(self, event, description) {
 }
 
 const SERVER_EVENTS = ['serverDescriptionChanged', 'error', 'close', 'timeout', 'parseError'];
-function destroyServer(server, options) {
+function destroyServer(server, options, callback) {
  options = options || {};
  SERVER_EVENTS.forEach(event => server.removeAllListeners(event));
- server.destroy(options);
+ server.destroy(options, callback);
 }
 
 /**
@@ -808,32 +808,43 @@ Mongos.prototype.unref = function() {
  * @param {boolean} [options.force=false] Force destroy the pool
  * @method
  */
-Mongos.prototype.destroy = function(options) {
- var self = this;
- // Transition state
- stateTransition(this, DESTROYED);
- // Get all proxies
- var proxies = this.connectedProxies.concat(this.connectingProxies);
- // Clear out any monitoring process
- if (this.haTimeoutId) clearTimeout(this.haTimeoutId);
+Mongos.prototype.destroy = function(options, callback) {
+ if (this.haTimeoutId) {
+ clearTimeout(this.haTimeoutId);
+ }
+
+ const proxies = this.connectedProxies.concat(this.connectingProxies);
+ let serverCount = proxies.length;
+ const serverDestroyed = () => {
+ serverCount--;
+ if (serverCount > 0) {
+ return;
+ }
+
+ emitTopologyDescriptionChanged(this);
+ emitSDAMEvent(this, 'topologyClosed', { topologyId: this.id });
+ stateTransition(this, DESTROYED);
+ if (typeof callback === 'function') {
+ callback(null, null);
+ }
+ };
+
+ if (serverCount === 0) {
+ serverDestroyed();
+ return;
+ }
 
  // Destroy all connecting servers
- proxies.forEach(function(server) {
+ proxies.forEach(server => {
  // Emit the sdam event
- self.emit('serverClosed', {
- topologyId: self.id,
+ this.emit('serverClosed', {
+ topologyId: this.id,
  address: server.name
  });
 
- destroyServer(server, options);
-
- // Move to list of disconnectedProxies
- moveServerFrom(self.connectedProxies, self.disconnectedProxies, server);
+ destroyServer(server, options, serverDestroyed);
+ moveServerFrom(this.connectedProxies, this.disconnectedProxies, server);
  });
- // Emit the final topology change
- emitTopologyDescriptionChanged(self);
- // Emit toplogy closing event
- emitSDAMEvent(this, 'topologyClosed', { topologyId: this.id });
 };
 
 /**