feat: remove legacy topology types

NODE-2318

Author: mbroadst

index.js

@@ -22,9 +22,6 @@ connect.Admin = require('./lib/admin');
 connect.MongoClient = require('./lib/mongo_client');
 connect.Db = require('./lib/db');
 connect.Collection = require('./lib/collection');
-connect.Server = require('./lib/topologies/server');
-connect.ReplSet = require('./lib/topologies/replset');
-connect.Mongos = require('./lib/topologies/mongos');
 connect.ReadPreference = core.ReadPreference;
 connect.GridStore = require('./lib/gridfs/grid_store');
 connect.Chunk = require('./lib/gridfs/chunk');
@@ -34,7 +31,6 @@ connect.CommandCursor = require('./lib/command_cursor');
 connect.Cursor = require('./lib/cursor');
 connect.GridFSBucket = require('./lib/gridfs-stream');
 // Exported to be used in tests not to be used anywhere else
-connect.CoreServer = core.Server;
 connect.CoreConnection = core.Connection;
 
 // BSON types exported

lib/core/uri_parser.js renamed to lib/connection_string.js

@@ -2,8 +2,8 @@
 const URL = require('url');
 const qs = require('querystring');
 const dns = require('dns');
-const MongoParseError = require('./error').MongoParseError;
-const ReadPreference = require('./topologies/read_preference');
+const MongoParseError = require('./core/error').MongoParseError;
+const ReadPreference = require('./core/topologies/read_preference');
 
 /**
  * The following regular expression validates a connection string and breaks the
@@ -698,4 +698,6 @@ function parseConnectionString(uri, options, callback) {
   callback(null, result);
 }
 
-module.exports = parseConnectionString;
+module.exports = {
+  parseConnectionString
+};

lib/core/cursor.js

@@ -7,7 +7,6 @@ const MongoNetworkError = require('./error').MongoNetworkError;
 const mongoErrorContextSymbol = require('./error').mongoErrorContextSymbol;
 const collationNotSupported = require('./utils').collationNotSupported;
 const ReadPreference = require('./topologies/read_preference');
-const isUnifiedTopology = require('./utils').isUnifiedTopology;
 const executeOperation = require('../operations/execute_operation');
 const Readable = require('stream').Readable;
 const SUPPORTS = require('../utils').SUPPORTS;
@@ -428,7 +427,7 @@ class CoreCursor extends Readable {
     const cursor = this;
 
     // NOTE: this goes away once cursors use `executeOperation`
-    if (isUnifiedTopology(cursor.topology) && cursor.topology.shouldCheckForSessionSupport()) {
+    if (cursor.topology.shouldCheckForSessionSupport()) {
       cursor.topology.selectServer(ReadPreference.primaryPreferred, err => {
         if (err) {
           callback(err);

lib/core/index.js

@@ -25,9 +25,6 @@ module.exports = {
   mongoErrorContextSymbol: require('./error').mongoErrorContextSymbol,
   // Core
   Connection: require('./connection/connection'),
-  Server: require('./topologies/server'),
-  ReplSet: require('./topologies/replset'),
-  Mongos: require('./topologies/mongos'),
   Logger: require('./connection/logger'),
   Cursor: require('./cursor').CoreCursor,
   ReadPreference: require('./topologies/read_preference'),
@@ -45,7 +42,5 @@ module.exports = {
   Plain: require('./auth/plain'),
   GSSAPI: require('./auth/gssapi'),
   ScramSHA1: require('./auth/scram').ScramSHA1,
-  ScramSHA256: require('./auth/scram').ScramSHA256,
-  // Utilities
-  parseConnectionString: require('./uri_parser')
+  ScramSHA256: require('./auth/scram').ScramSHA256
 };