From 78520507d892dcca6b352f4197259a22da9cfc41 Mon Sep 17 00:00:00 2001
From: Fedor Indutny <fedor.indutny@gmail.com>
Date: Fri, 30 Sep 2011 16:41:21 +0700
Subject: [PATCH] [lib] callback precendence

---
 lib/Porter.js | 68 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 43 insertions(+), 25 deletions(-)

diff --git a/lib/Porter.js b/lib/Porter.js
index 1c2ca7c..bf56e09 100644
--- a/lib/Porter.js
+++ b/lib/Porter.js
@@ -42,17 +42,34 @@
 
     this.headers = this.options.headers;
 
-    this._listeners = {
-      'loading': noop,
-      'loaded': noop,
-      'interactive': noop,
-      'default': noop
+    function addListener(self, action, listener) {
+      var listeners = self._listeners[action];
+      listeners ?
+          listeners.push(listener)
+          :
+          (self._listeners[action] = [listener]);
+    };
+
+    function executeListener(self, action) {
+      var args = Array.prototype.slice.call(arguments, 2),
+          listeners = self._listeners[action];
+
+      if (listeners) {
+        for (var i = 0, l = listeners.length; i < l; i++) {
+          // Returning false will stop propagation
+          if (listeners[i].apply(null, args) === false) break;
+        }
+        return true;
+      } else {
+        return false;
+      }
+
     };
 
     this.on = function(listeners) {
       for (var listener in listeners) {
         if (listeners.hasOwnProperty(listener)) {
-          self._listeners[listener] = listeners[listener];
+          addListener(self, listener, listeners[listener]);
         }
       }
       return self;
@@ -105,23 +122,23 @@
           }
         }
 
-        // merge the global _listeners into this xhr.
-        for(l in self._listeners) {
-          if(self._listeners.hasOwnProperty(l)) {
-            ajax._listeners[l] = self._listeners[l];
-          }
-        }
-
         // is callbacks actually plural? if so, merge.
         if(!(typeof callbacks === 'function')) {
           for(c in callbacks) {
             if(callbacks.hasOwnProperty(c)) {
-              ajax._listeners[c] = callbacks[c];
+              addListener(ajax, c, callbacks[c]);
             }
           }
         }
         else {
-          ajax._listeners['default'] = callbacks;
+          addListener(ajax, 'default', callbacks);
+        }
+
+        // merge the global _listeners into this xhr.
+        for(l in self._listeners) {
+          if(self._listeners.hasOwnProperty(l)) {
+            addListener(ajax, l, self._listeners[l]);
+          }
         }
 
         ajax.xhr.open(conf.type, conf.url, true);
@@ -156,7 +173,7 @@
             ajax.xhr.send(JSON.stringify(conf.data)); 
 
           }
-          catch(ex) { ajax._listeners['default'](ex, null, null, null); }
+          catch(ex) { executeListener(ajax, 'default', ex, null, null, null); }
         }
         else {
           ajax.xhr.send();
@@ -166,13 +183,13 @@
 
           switch (ajax.xhr.readyState) {
             case 1:
-              ajax._listeners.loading();
+              executeListener(ajax, 'loading');
             break;
             case 2:
-              ajax._listeners.loaded();
+              executeListener(ajax, 'loaded');
             break;
             case 3:
-              ajax._listeners.interactive();
+              executeListener(ajax, 'interactive');
             break;
             case 4:
 
@@ -213,7 +230,7 @@
                 response = isJSON(response) ? JSON.parse(response) : response;
               }
               catch(ex) {
-                ajax._listeners['default'](ex, null, null, null);
+                executeListener(ajax, 'default', ex, null, null, null);
               }
 
               // if there is validation, and it returns anything other 
@@ -225,11 +242,12 @@
                 validation = validator['inbound'](response);
               }
 
-              if(ajax._listeners[status]) { 
-                ajax._listeners[status](validation ? null : validation, response, statusText, self.xhr);
-              }
-              else if(ajax._listeners['default']) {
-                ajax._listeners['default'](validation ? null : validation, response, statusText, self.xhr);
+              var codeAction = executeListener(ajax, status,
+                                               validation ? null : validation,
+                                               response, statusText, self.xhr);
+              if (!codeAction) {
+                executeListener(ajax, 'default', validation ? null : validation,
+                                response, statusText, self.xhr);
               }
 
               cache[conf.url] = response;