diff --git a/lib/Curl.js b/lib/Curl.js
index aa11a24..0101caa 100644
--- a/lib/Curl.js
+++ b/lib/Curl.js
@@ -1,6 +1,6 @@
 // Generated by ToffeeScript 1.4.0
 (function() {
-  var Curl, id, m, p;
+  var Curl, curls, id, m, p;
 
   try {
     Curl = require(__dirname + '/../build/Release/node-curl').Curl;
@@ -53,16 +53,29 @@
     DEBUG: 'DEBUG'
   };
 
+  id = 0;
+
+  curls = {};
+
   Curl.prototype.on = function(event, callback) {
+    var _this = this;
     switch (event) {
       case 'data':
-        this.on_write = callback;
+        this.on_write = function(chunk) {
+          return callback.call(_this, chunk);
+        };
         break;
       case 'error':
-        this.on_error = callback;
+        this.on_error = function(e) {
+          delete curls[_this.id];
+          return callback.call(_this, e);
+        };
         break;
       case 'end':
-        this.on_end = callback;
+        this.on_end = function() {
+          delete curls[_this.id];
+          return callback.call(_this);
+        };
         break;
       default:
         throw new Error("invalid event type " + event);
@@ -71,13 +84,13 @@
   };
 
   Curl.prototype.close = function() {
+    delete curls[this.id];
     return this.close_();
   };
 
-  id = 0;
-
   Curl.prototype.perform = function() {
     this.id = ++id;
+    curls[this.id] = this;
     this.perform_();
     Curl.process();
     return this;
diff --git a/lib/Curl.toffee b/lib/Curl.toffee
index 25dcf84..b06d7bf 100644
--- a/lib/Curl.toffee
+++ b/lib/Curl.toffee
@@ -42,28 +42,37 @@ Curl.user_options =
   RAW: 'RAW'
   DEBUG: 'DEBUG'
 
+id = 0
+curls = {}
+
 # on 'data' must be returns the chunk length
 Curl::on = (event, callback) ->
   switch event
     when 'data'
       # (Buffer chunk) ->
-      @on_write = callback
+      @on_write = (chunk) =>
+        callback.call @, chunk
     when 'error'
       # (Error error) ->
-      @on_error = callback
+      @on_error = (e) =>
+        delete curls[@id]
+        callback.call @, e
     when 'end'
       # () ->
-      @on_end = callback
+      @on_end = =>
+        delete curls[@id]
+        callback.call @
     else
       throw new Error("invalid event type #{event}")
   @
 
 Curl::close = () ->
+  delete curls[@id]
   @close_()
 
-id = 0
 Curl::perform = ->
   @id = ++id
+  curls[@id] = @
   @perform_()
   Curl.process()
   @
diff --git a/src/node-curl.h b/src/node-curl.h
index 715093a..e7460ae 100644
--- a/src/node-curl.h
+++ b/src/node-curl.h
@@ -29,14 +29,12 @@ class NodeCurl
 	CURL  * curl;
 	v8::Persistent<v8::Object> handle;
 
-	v8::Persistent<v8::Object> ref;
-	int ref_no;
 	bool  in_curlm;
 	std::vector<curl_slist*> slists;
 	std::map<int, std::string> strings;
 
 	NodeCurl(v8::Handle<v8::Object> object)
-	: in_curlm(false), ref_no(0)
+	: in_curlm(false)
 	{
 		++count;
 		v8::V8::AdjustAmountOfExternalAllocatedMemory(2*4096);
@@ -121,7 +119,11 @@ class NodeCurl
 		{
 			node::Buffer * buffer = node::Buffer::New(data, n);
 			v8::Handle<v8::Value> argv[] = { buffer->handle_ };
-			n = cb->ToObject()->CallAsFunction(handle, 1, argv)->Int32Value();
+			v8::Handle<v8::Value> rt = cb->ToObject()->CallAsFunction(handle, 1, argv);
+			if (rt.IsEmpty())
+				return 0;
+			else
+				return rt->Int32Value();
 		}
 		return n;
 	}
@@ -330,12 +332,6 @@ class NodeCurl
 						curl->on_end(&msg_copy);
 					else
 						curl->on_error(&msg_copy);
-
-					--curl->ref_no;
-					if (curl->ref_no == 0)
-						curl->ref.Dispose();
-
-
 				}
 			}
 		}
@@ -360,10 +356,6 @@ class NodeCurl
 		curl->in_curlm = true;
 		++running_handles;
 
-		if (curl->ref_no == 0)
-			curl->ref=v8::Persistent<v8::Object>::New(curl->handle);
-		++curl->ref_no;
-
 		return args.This();
 	}