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var util = require('util');
var fs = require('fs');
var events = require('events');
var dns = require('dns');
var IOWatcher = process.binding('io_watcher').IOWatcher;
var binding = process.binding('net');
var constants = process.binding('constants');
var socket = binding.socket;
var recvfrom = binding.recvfrom;
var close = binding.close;
var ENOENT = constants.ENOENT;
function isPort(x) { return parseInt(x) >= 0; }
var pool = null;
function getPool() {
/* TODO: this effectively limits you to 8kb maximum packet sizes */
var minPoolAvail = 1024 * 8;
var poolSize = 1024 * 64;
if (pool === null || (pool.used + minPoolAvail > pool.length)) {
pool = new Buffer(poolSize);
pool.used = 0;
}
return pool;
}
function dnsLookup(type, hostname, callback) {
var family = (type ? ((type === 'udp6') ? 6 : 4) : null);
dns.lookup(hostname, family, function(err, ip, addressFamily) {
if (!err && family && addressFamily !== family) {
err = new Error('no address found in family ' + type +
' for ' + hostname);
}
callback(err, ip, addressFamily);
});
}
function Socket(type, listener) {
events.EventEmitter.call(this);
var self = this;
self.type = type;
if (type === 'unix_dgram' || type === 'udp4' || type === 'udp6') {
self.fd = socket(self.type);
} else {
throw new Error('Bad socket type specified. Valid types are: ' +
'unix_dgram, udp4, udp6');
}
if (typeof listener === 'function') {
self.on('message', listener);
}
self.watcher = new IOWatcher();
self.watcher.host = self;
self.watcher.callback = function() {
while (self.fd) {
var p = getPool();
var rinfo = recvfrom(self.fd, p, p.used, p.length - p.used, 0);
if (!rinfo) return;
self.emit('message', p.slice(p.used, p.used + rinfo.size), rinfo);
p.used += rinfo.size;
}
};
if (self.type === 'udp4' || self.type === 'udp6') {
self._startWatcher();
}
}
util.inherits(Socket, events.EventEmitter);
exports.Socket = Socket;
exports.createSocket = function(type, listener) {
return new Socket(type, listener);
};
Socket.prototype.bind = function() {
var self = this;
if (this.type === 'unix_dgram') {
// bind(path)
if (typeof arguments[0] !== 'string') {
throw new Error('unix_dgram sockets must be bound to a path in ' +
'the filesystem');
}
this.path = arguments[0];
// unlink old file, OK if it doesn't exist
fs.unlink(this.path, function(err) {
if (err && err.errno !== ENOENT) {
throw err;
} else {
try {
binding.bind(self.fd, self.path);
self._startWatcher();
self.emit('listening');
} catch (err) {
console.log('Error in unix_dgram bind of ' + self.path);
console.log(err.stack);
throw err;
}
}
});
} else if (this.type === 'udp4' || this.type === 'udp6') {
// bind(port, [address])
if (arguments[1] === undefined) {
// Not bind()ing a specific address. Use INADDR_ANY and OS will pick one.
// The address can be found with server.address()
binding.bind(self.fd, arguments[0]);
this.emit('listening');
} else {
// the first argument is the port, the second an address
this.port = arguments[0];
dnsLookup(this.type, arguments[1], function(err, ip, addressFamily) {
if (err) {
self.emit('error', err);
} else {
self.ip = ip;
binding.bind(self.fd, self.port, ip);
self.emit('listening');
}
});
}
}
};
Socket.prototype._startWatcher = function() {
if (! this._watcherStarted) {
// listen for read ready, not write ready
this.watcher.set(this.fd, true, false);
this.watcher.start();
this._watcherStarted = true;
}
};
Socket.prototype.address = function() {
return binding.getsockname(this.fd);
};
Socket.prototype.setBroadcast = function(arg) {
if (arg) {
return binding.setBroadcast(this.fd, 1);
} else {
return binding.setBroadcast(this.fd, 0);
}
};
Socket.prototype.setTTL = function(arg) {
var newttl = parseInt(arg);
if (newttl > 0 && newttl < 256) {
return binding.setTTL(this.fd, newttl);
} else {
throw new Error('New TTL must be between 1 and 255');
}
};
// translate arguments from JS API into C++ API, possibly after DNS lookup
Socket.prototype.send = function(buffer, offset, length) {
var self = this;
if (typeof offset !== 'number' || typeof length !== 'number') {
throw new Error('send takes offset and length as args 2 and 3');
}
if (this.type === 'unix_dgram') {
// send(buffer, offset, length, path [, callback])
if (typeof arguments[3] !== 'string') {
throw new Error('unix_dgram sockets must send to a path ' +
'in the filesystem');
}
self.sendto(buffer, offset, length, arguments[3], null, arguments[4]);
} else if (this.type === 'udp4' || this.type === 'udp6') {
// send(buffer, offset, length, port, address [, callback])
if (typeof arguments[4] !== 'string') {
throw new Error(this.type + ' sockets must send to port, address');
}
if (binding.isIP(arguments[4])) {
self.sendto(arguments[0], arguments[1], arguments[2], arguments[3],
arguments[4], arguments[5]);
} else {
var port = arguments[3],
callback = arguments[5];
dnsLookup(this.type, arguments[4], function(err, ip, addressFamily) {
if (err) { // DNS error
if (callback) {
callback(err);
}
self.emit('error', err);
return;
}
self.sendto(buffer, offset, length, port, ip, callback);
});
}
}
};
Socket.prototype.sendto = function(buffer,
offset,
length,
port,
addr,
callback) {
try {
var bytes = binding.sendto(this.fd, buffer, offset, length, 0, port, addr);
} catch (err) {
if (callback) {
callback(err);
}
return;
}
if (callback) {
callback(null, bytes);
}
};
Socket.prototype.close = function() {
var self = this;
if (!this.fd) throw new Error('Not running');
this.watcher.stop();
this._watcherStarted = false;
close(this.fd);
this.fd = null;
if (this.type === 'unix_dgram' && this.path) {
fs.unlink(this.path, function() {
self.emit('close');
});
} else {
this.emit('close');
}
};
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