better option parsing for socket.write()

doc/api/net.markdown

@@ -196,16 +196,22 @@ context of the defined or default list of trusted CA certificates.
 Returns a JSON structure detailing the peer's certificate, containing a dictionary
 with keys for the certificate `'subject'`, `'issuer'`, `'valid_from'` and `'valid_to'`.
 
-#### stream.write(data, encoding='ascii')
+#### stream.write(data, [encoding])
 
-Sends data on the stream. The second parameter specifies the encoding in
-the case of a string--it defaults to ASCII because encoding to UTF8 is rather
-slow.
+Sends data on the stream. The second parameter specifies the encoding in the
+case of a string--it defaults to UTF8 encoding.
 
 Returns `true` if the entire data was flushed successfully to the kernel
 buffer. Returns `false` if all or part of the data was queued in user memory.
 `'drain'` will be emitted when the buffer is again free.
 
+#### stream.write(data, [encoding], [fileDescriptor])
+
+For UNIX sockets, it is possible to send a file descriptor through the
+stream. Simply add the `fileDescriptor` argument and listen for the `'fd'`
+event on the other end.
+
+
 #### stream.end([data], [encoding])
 
 Half-closes the stream. I.E., it sends a FIN packet. It is possible the

lib/net.js

@@ -264,7 +264,33 @@ Object.defineProperty(Stream.prototype, 'readyState', {
 // Returns true if all the data was flushed to socket. Returns false if
 // something was queued. If data was queued, then the 'drain' event will
 // signal when it has been finally flushed to socket.
-Stream.prototype.write = function(data, encoding, fd) {
+Stream.prototype.write = function(data /* [encoding], [fd], [cb] */) {
+  var encoding, fd, cb;
+
+  // parse arguments
+  if (typeof arguments[1] == 'string') {
+    encoding = arguments[1];
+    if (typeof arguments[2] == 'number') {
+      fd = arguments[2];
+      cb = arguments[3];
+    } else {
+      cb = arguments[2];
+    }
+  } else if (typeof arguments[1] == 'number') {
+    fd = arguments[1];
+    cb = arguments[2];
+  } else if (typeof arguments[2] == 'number') {
+    // This case is to support old calls when the encoding argument
+    // was not optional: s.write(buf, undefined, pipeFDs[1])
+    encoding = arguments[1];
+    fd = arguments[2];
+    cb = arguments[3];
+  } else {
+    cb = arguments[1];
+  }
+
+  // TODO - actually use cb
+
   if (this._connecting || (this._writeQueue && this._writeQueue.length)) {
     if (!this._writeQueue) {
       this._writeQueue = [];

test/simple/test-sendfd.js

@@ -94,7 +94,7 @@ var srv = net.createServer(function(s) {
   buf.write(JSON.stringify(DATA) + '\n', 'utf8');
 
   s.write(str, 'utf8', pipeFDs[1]);
-  if (s.write(buf, undefined, pipeFDs[1])) {
+  if (s.write(buf, pipeFDs[1])) {
     netBinding.close(pipeFDs[1]);
   } else {
     s.addListener('drain', function() {