call: refactor abort() to handle differences in node versions

On a call to request.abort() three different scenarios exist

 - node.js 0.10 emits error event
 - node.js 0.12 silently aborts
 - io.js 1.x emits abort event

This commit ...

 - silences errors after abort()
 - implements an abort event
 - implements an plugin-abort event
 - removes request.socket.destroy() code

doc/api.markdown

@@ -144,6 +144,9 @@ Emitted after the request object has been created and the send-buffer has been f
 
 `function({Object} request)`
 
+### Event 'abort'
+Emitted when a pending connect or active request is aborted.
+
 ### Event 'response'
 Emitted after the response headers have been received.
 

doc/plugin-api.markdown

@@ -68,6 +68,11 @@ Emitted directly after a request object has been created.
 
 `function({Call} call, {Object} options, {Request} request)`
 
+### Event: 'plugin-abort'
+Emitted when a pending connect or active request is aborted.
+
+`function({Call} call, {Object} options)`
+
 ### Event: 'plugin-response'
 Emitted when response headers have been received.
 

lib/call.js

@@ -43,7 +43,6 @@ function Call(rail, opt_options) {
   this.ended = false;
   this.aborted = false;     // call abort flag
   this._aborted = false;    // request abort flag (reset-able)
-  this._destroyed = false;  // socket destroyed flag (reset-able)
   this._reason = '';
 
   // stack of request configurations
@@ -205,12 +204,11 @@ Call.prototype.__request = function(opt_callback) {
   });
 
   request.on('error', function(err) {
-    if (self._aborted || self._destroyed) {
-      err.reason = self._reason;
+    if (self._aborted) {
+      return; // ignore errors after a request has been aborted, see call.__abort()
     }
     self.__emit('error', err);
 
-    // TODO: clear when the actual error is emitted
     self.request = null;
     self.response = null;
 
@@ -245,6 +243,7 @@ Call.prototype.__request = function(opt_callback) {
 Call.prototype.__emit = function(event, object) {
   var listener;
 
+
   if (this._interceptors[event] && this._interceptors[event].length) {
     listener = this._interceptors[event].shift();
     listener(this, this._stack[this._pointer], object);
@@ -268,28 +267,39 @@ Call.prototype.__intercept = function(event, interceptor) {
 
 Call.prototype.__clear = function() {
   this._aborted = false;
-  this._destroyed = false;
   this._reason = '';
-
   this._interceptors = {};
 };
 
 
-Call.prototype.__abort = function(opt_reason) {
+Call.prototype.__abort = function() {
+  // request.abort()
+  //   - node.js 0.10 emits error event
+  //   - node.js 0.12 silently aborts
+  //   - io.js 1.x emits abort event
+  var self = this;
+
   if (this.request) {
     if (typeof this.request.abort === 'function' &&
         this.request.aborted === undefined) {
 
       this._aborted = true;
-      this._reason = opt_reason || 'unknown';
       this.request.abort();
+      self.__clear();
+
+      setImmediate(function() {
+        self.rail.emit('plugin-abort', self, self._stack[self._pointer]);
 
-    } else if (this.request.socket &&
-        typeof this.request.socket.destroy === 'function') {
+        if (self.aborted) {
+          self.emit('abort');
 
-      this._destroyed = true;
-      this._reason = opt_reason || 'unknown';
-      this.request.socket.destroy();
+          if (self._buffer) {
+            self._buffer.close();
+            self._buffer.dump();
+            self._buffer = null;
+          }
+        }
+      });
     }
     return true;
   }
@@ -299,14 +309,10 @@ Call.prototype.__abort = function(opt_reason) {
 
 
 Call.prototype.abort = function() {
-  this.aborted = true;
-
-  if (this._buffer) {
-    this._buffer.dump();
-    this._buffer = null;
+  if (!this.aborted) {
+    this.aborted = true;
+    this.__abort(true);
   }
-
-  this.__abort('user');
 };
 
 
@@ -324,6 +330,7 @@ Call.prototype.end = function(chunk, encoding, opt_callback) {
   } else if (!encoding) {
     encoding = null;
   }
+
   opt_callback = opt_callback || function() {};
 
   if (this.ended) {
@@ -353,7 +360,7 @@ Call.prototype.end = function(chunk, encoding, opt_callback) {
         self._buffer.close();
       }
       request.end();
-      opt_callback(err2);
+      opt_callback();
     });
   });