dgram: make _createSocketHandle() internal only

_createSocketHandle() is used internally by the cluster module.
This commit makes it internal only API.

PR-URL: #21923
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Wyatt Preul <wpreul@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

lib/dgram.js

@@ -21,16 +21,18 @@
 
 'use strict';
 
-const assert = require('assert');
 const errors = require('internal/errors');
-const { kStateSymbol } = require('internal/dgram');
+const {
+  kStateSymbol,
+  _createSocketHandle,
+  newHandle
+} = require('internal/dgram');
 const {
   ERR_INVALID_ARG_TYPE,
   ERR_MISSING_ARGS,
   ERR_SOCKET_ALREADY_BOUND,
   ERR_SOCKET_BAD_BUFFER_SIZE,
   ERR_SOCKET_BAD_PORT,
-  ERR_SOCKET_BAD_TYPE,
   ERR_SOCKET_BUFFER_SIZE,
   ERR_SOCKET_CANNOT_SEND,
   ERR_SOCKET_DGRAM_NOT_RUNNING
@@ -47,9 +49,6 @@ const { UV_UDP_REUSEADDR } = process.binding('constants').os;
 
 const { UDP, SendWrap } = process.binding('udp_wrap');
 
-// Lazy load for startup performance.
-let dns;
-
 const BIND_STATE_UNBOUND = 0;
 const BIND_STATE_BINDING = 1;
 const BIND_STATE_BOUND = 2;
@@ -64,59 +63,6 @@ const errnoException = errors.errnoException;
 const exceptionWithHostPort = errors.exceptionWithHostPort;
 
 
-function lookup4(lookup, address, callback) {
-  return lookup(address || '127.0.0.1', 4, callback);
-}
-
-
-function lookup6(lookup, address, callback) {
-  return lookup(address || '::1', 6, callback);
-}
-
-
-function newHandle(type, lookup) {
-  if (lookup === undefined) {
-    if (dns === undefined) dns = require('dns');
-    lookup = dns.lookup;
-  } else if (typeof lookup !== 'function')
-    throw new ERR_INVALID_ARG_TYPE('lookup', 'Function', lookup);
-
-  if (type === 'udp4') {
-    const handle = new UDP();
-    handle.lookup = lookup4.bind(handle, lookup);
-    return handle;
-  }
-
-  if (type === 'udp6') {
-    const handle = new UDP();
-    handle.lookup = lookup6.bind(handle, lookup);
-    handle.bind = handle.bind6;
-    handle.send = handle.send6;
-    return handle;
-  }
-
-  throw new ERR_SOCKET_BAD_TYPE();
-}
-
-
-function _createSocketHandle(address, port, addressType, fd, flags) {
-  // Opening an existing fd is not supported for UDP handles.
-  assert(typeof fd !== 'number' || fd < 0);
-
-  var handle = newHandle(addressType);
-
-  if (port || address) {
-    var err = handle.bind(address, port || 0, flags);
-    if (err) {
-      handle.close();
-      return err;
-    }
-  }
-
-  return handle;
-}
-
-
 function Socket(type, listener) {
   EventEmitter.call(this);
   var lookup;
@@ -739,7 +685,6 @@ Socket.prototype.getSendBufferSize = function() {
 
 
 module.exports = {
-  _createSocketHandle,
   createSocket,
   Socket
 };

lib/internal/cluster/shared_handle.js

@@ -1,6 +1,6 @@
 'use strict';
 const assert = require('assert');
-const dgram = require('dgram');
+const dgram = require('internal/dgram');
 const net = require('net');
 
 module.exports = SharedHandle;

lib/internal/dgram.js

@@ -1,4 +1,70 @@
 'use strict';
+const assert = require('assert');
+const { codes } = require('internal/errors');
+const { UDP } = process.binding('udp_wrap');
+const { ERR_INVALID_ARG_TYPE, ERR_SOCKET_BAD_TYPE } = codes;
 const kStateSymbol = Symbol('state symbol');
+let dns;  // Lazy load for startup performance.
 
-module.exports = { kStateSymbol };
+
+function lookup4(lookup, address, callback) {
+  return lookup(address || '127.0.0.1', 4, callback);
+}
+
+
+function lookup6(lookup, address, callback) {
+  return lookup(address || '::1', 6, callback);
+}
+
+
+function newHandle(type, lookup) {
+  if (lookup === undefined) {
+    if (dns === undefined) {
+      dns = require('dns');
+    }
+
+    lookup = dns.lookup;
+  } else if (typeof lookup !== 'function') {
+    throw new ERR_INVALID_ARG_TYPE('lookup', 'Function', lookup);
+  }
+
+  if (type === 'udp4') {
+    const handle = new UDP();
+
+    handle.lookup = lookup4.bind(handle, lookup);
+    return handle;
+  }
+
+  if (type === 'udp6') {
+    const handle = new UDP();
+
+    handle.lookup = lookup6.bind(handle, lookup);
+    handle.bind = handle.bind6;
+    handle.send = handle.send6;
+    return handle;
+  }
+
+  throw new ERR_SOCKET_BAD_TYPE();
+}
+
+
+function _createSocketHandle(address, port, addressType, fd, flags) {
+  // Opening an existing fd is not supported for UDP handles.
+  assert(typeof fd !== 'number' || fd < 0);
+
+  const handle = newHandle(addressType);
+
+  if (port || address) {
+    const err = handle.bind(address, port || 0, flags);
+
+    if (err) {
+      handle.close();
+      return err;
+    }
+  }
+
+  return handle;
+}
+
+
+module.exports = { kStateSymbol, _createSocketHandle, newHandle };

test/parallel/test-dgram-create-socket-handle.js

@@ -1,9 +1,9 @@
+// Flags: --expose-internals
 'use strict';
 const common = require('../common');
 const assert = require('assert');
-const dgram = require('dgram');
+const { _createSocketHandle } = require('internal/dgram');
 const UDP = process.binding('udp_wrap').UDP;
-const _createSocketHandle = dgram._createSocketHandle;
 
 // Throws if an "existing fd" is passed in.
 common.expectsError(() => {