cluster: simplify process event handling

This simplify the internalMessage and exit event handling
And simply relay message and error event to the worker object
Note that the error event was not relayed before

lib/cluster.js

@@ -169,7 +169,7 @@ function handleResponse(outMessage, outHandle, inMessage, inHandle, worker) {
 
 // Handle messages from both master and workers
 var messageHandingObject = {};
-function handleMessage(inMessage, inHandle, worker) {
+function handleMessage(worker, inMessage, inHandle) {
 
   //Remove internal prefix
   var message = extendObject({}, inMessage);
@@ -303,27 +303,13 @@ function Worker(customEnv) {
     });
   }
 
-  // Internal message: handle message
-  this.process.on('internalMessage', function(message, handle) {
-    debug('recived: ', message);
+  // handle internalMessage and exit event
+  this.process.on('internalMessage', handleMessage.bind(null, this));
+  this.process.on('exit', prepareDeath.bind(null, this, 'dead', 'death'));
 
-    // relay to handleMessage
-    handleMessage(message, handle, self);
-    return;
-  });
-
-  // Non-internal message: relay to Worker object
-  this.process.on('message', function(message, handle) {
-    self.emit('message', message, handle);
-  });
-
-  // Handle exit
-  self.process.on('exit', function() {
-    debug('worker id=' + self.uniqueID + ' died');
-
-    // Prepare worker to die and emit events
-    prepareDeath(self, 'dead', 'death');
-  });
+  // relay message and error
+  this.process.on('message', this.emit.bind(this, 'message'));
+  this.process.on('error', this.emit.bind(this, 'error'));
 
 }
 util.inherits(Worker, EventEmitter);