dgram: refactor SO_RCVBUF and SO_SNDBUF methods

This commit refactors the get/set send/receive buffer size
methods in the following ways:

- Use booleans instead of strings and numbers to differentiate
between the send and receive buffers.
- Reduce the amount of branching and complexity in the C++ code.

Refs: #13623
PR-URL: #15483
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/dgram.js

@@ -40,6 +40,9 @@ const BIND_STATE_UNBOUND = 0;
 const BIND_STATE_BINDING = 1;
 const BIND_STATE_BOUND = 2;
 
+const RECV_BUFFER = true;
+const SEND_BUFFER = false;
+
 // Lazily loaded
 var cluster = null;
 
@@ -146,10 +149,10 @@ function startListening(socket) {
  socket.fd = -42; // compatibility hack
 
  if (socket[kOptionSymbol].recvBufferSize)
- bufferSize(socket, socket[kOptionSymbol].recvBufferSize, 'recv');
+ bufferSize(socket, socket[kOptionSymbol].recvBufferSize, RECV_BUFFER);
 
  if (socket[kOptionSymbol].sendBufferSize)
- bufferSize(socket, socket[kOptionSymbol].sendBufferSize, 'send');
+ bufferSize(socket, socket[kOptionSymbol].sendBufferSize, SEND_BUFFER);
 
  socket.emit('listening');
 }
@@ -172,10 +175,7 @@ function bufferSize(self, size, buffer) {
  throw new errors.TypeError('ERR_SOCKET_BAD_BUFFER_SIZE');
 
  try {
- if (buffer === 'recv')
- return self._handle.bufferSize(size, 0);
- else
- return self._handle.bufferSize(size, 1);
+ return self._handle.bufferSize(size, buffer);
  } catch (e) {
  throw new errors.Error('ERR_SOCKET_BUFFER_SIZE', e);
  }
@@ -677,22 +677,22 @@ Socket.prototype.unref = function() {
 
 
 Socket.prototype.setRecvBufferSize = function(size) {
- bufferSize(this, size, 'recv');
+ bufferSize(this, size, RECV_BUFFER);
 };
 
 
 Socket.prototype.setSendBufferSize = function(size) {
- bufferSize(this, size, 'send');
+ bufferSize(this, size, SEND_BUFFER);
 };
 
 
 Socket.prototype.getRecvBufferSize = function() {
- return bufferSize(this, 0, 'recv');
+ return bufferSize(this, 0, RECV_BUFFER);
 };
 
 
 Socket.prototype.getSendBufferSize = function() {
- return bufferSize(this, 0, 'send');
+ return bufferSize(this, 0, SEND_BUFFER);
 };
 
 

src/udp_wrap.cc

@@ -233,31 +233,26 @@ void UDPWrap::BufferSize(const FunctionCallbackInfo<Value>& args) {
  args.GetReturnValue().Set(UV_EBADF));
 
  CHECK(args[0]->IsUint32());
- CHECK(args[1]->IsUint32());
+ CHECK(args[1]->IsBoolean());
+ bool is_recv = args[1].As<v8::Boolean>()->Value();
+ const char* uv_func_name = is_recv ? "uv_recv_buffer_size" :
+ "uv_send_buffer_size";
 
- if (!args[0]->IsInt32()) {
- if (args[1].As<Uint32>()->Value() == 0)
- return env->ThrowUVException(UV_EINVAL, "uv_recv_buffer_size");
- else
- return env->ThrowUVException(UV_EINVAL, "uv_send_buffer_size");
- }
+ if (!args[0]->IsInt32())
+ return env->ThrowUVException(UV_EINVAL, uv_func_name);
 
- int err;
+ uv_handle_t* handle = reinterpret_cast<uv_handle_t*>(&wrap->handle_);
  int size = static_cast<int>(args[0].As<Uint32>()->Value());
- if (args[1].As<Uint32>()->Value() == 0) {
- err = uv_recv_buffer_size(reinterpret_cast<uv_handle_t*>(&wrap->handle_),
- &size);
- } else {
- err = uv_send_buffer_size(reinterpret_cast<uv_handle_t*>(&wrap->handle_),
- &size);
- }
+ int err;
+
+ if (is_recv)
+ err = uv_recv_buffer_size(handle, &size);
+ else
+ err = uv_send_buffer_size(handle, &size);
+
+ if (err != 0)
+ return env->ThrowUVException(err, uv_func_name);
 
- if (err != 0) {
- if (args[1].As<Uint32>()->Value() == 0)
- return env->ThrowUVException(err, "uv_recv_buffer_size");
- else
- return env->ThrowUVException(err, "uv_send_buffer_size");
- }
  args.GetReturnValue().Set(size);
 }