From b735dcb31251a31f411adf119180b83547f3ee32 Mon Sep 17 00:00:00 2001
From: TJ Holowaychuk <tj@vision-media.ca>
Date: Thu, 22 Dec 2011 05:03:16 -0800
Subject: [PATCH] Added guillermo's EventEmitter. Closes #16

---
 lib/events.js | 171 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 146 insertions(+), 25 deletions(-)

diff --git a/lib/events.js b/lib/events.js
index 91e6bf4e6..b8202ad93 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -1,55 +1,176 @@
 
-/*!
- * EventEmitter
- * Copyright (c) 2011 TJ Holowaychuk <tj@vision-media.ca>
- * MIT Licensed
+/**
+ * Module exports.
+ */
+
+/**
+ * Check if `obj` is an array.
  */
 
-// TODO: own library, since tons of my libs use this :D
+function isArray(obj) {
+  return '[object Array]' == {}.toString.call(obj);
+}
 
 /**
- * Slice reference.
+ * Event emitter constructor.
+ *
+ * @api public.
  */
 
-var slice = [].slice;
+function EventEmitter(){};
 
 /**
- * EventEmitter.
+ * Adds a listener.
+ *
+ * @api public
  */
 
-function EventEmitter() {
-  this.callbacks = {};
+EventEmitter.prototype.on = function (name, fn) {
+  if (!this.$events) {
+    this.$events = {};
+  }
+
+  if (!this.$events[name]) {
+    this.$events[name] = fn;
+  } else if (isArray(this.$events[name])) {
+    this.$events[name].push(fn);
+  } else {
+    this.$events[name] = [this.$events[name], fn];
+  }
+
+  return this;
 };
 
+EventEmitter.prototype.addListener = EventEmitter.prototype.on;
+
 /**
- * Listen on the given `event` with `fn`.
+ * Adds a volatile listener.
  *
- * @param {String} event
- * @param {Function} fn
+ * @api public
  */
 
-EventEmitter.prototype.on = function(event, fn){
-  (this.callbacks[event] = this.callbacks[event] || [])
-    .push(fn);
+EventEmitter.prototype.once = function (name, fn) {
+  var self = this;
+
+  function on () {
+    self.removeListener(name, on);
+    fn.apply(this, arguments);
+  };
+
+  on.listener = fn;
+  this.on(name, on);
+
   return this;
 };
 
 /**
- * Emit `event` with the given args.
+ * Removes a listener.
  *
- * @param {String} event
- * @param {Mixed} ...
+ * @api public
  */
 
-EventEmitter.prototype.emit = function(event){
-  var args = slice.call(arguments, 1)
-    , callbacks = this.callbacks[event];
+EventEmitter.prototype.removeListener = function (name, fn) {
+  if (this.$events && this.$events[name]) {
+    var list = this.$events[name];
 
-  if (callbacks) {
-    for (var i = 0, len = callbacks.length; i < len; ++i) {
-      callbacks[i].apply(this, args);
+    if (isArray(list)) {
+      var pos = -1;
+
+      for (var i = 0, l = list.length; i < l; i++) {
+        if (list[i] === fn || (list[i].listener && list[i].listener === fn)) {
+          pos = i;
+          break;
+        }
+      }
+
+      if (pos < 0) {
+        return this;
+      }
+
+      list.splice(pos, 1);
+
+      if (!list.length) {
+        delete this.$events[name];
+      }
+    } else if (list === fn || (list.listener && list.listener === fn)) {
+      delete this.$events[name];
     }
   }
 
   return this;
 };
+
+/**
+ * Removes all listeners for an event.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.removeAllListeners = function (name) {
+  if (name === undefined) {
+    this.$events = {};
+    return this;
+  }
+
+  if (this.$events && this.$events[name]) {
+    this.$events[name] = null;
+  }
+
+  return this;
+};
+
+/**
+ * Gets all listeners for a certain event.
+ *
+ * @api publci
+ */
+
+EventEmitter.prototype.listeners = function (name) {
+  if (!this.$events) {
+    this.$events = {};
+  }
+
+  if (!this.$events[name]) {
+    this.$events[name] = [];
+  }
+
+  if (!isArray(this.$events[name])) {
+    this.$events[name] = [this.$events[name]];
+  }
+
+  return this.$events[name];
+};
+
+/**
+ * Emits an event.
+ *
+ * @api public
+ */
+
+EventEmitter.prototype.emit = function (name) {
+  if (!this.$events) {
+    return false;
+  }
+
+  var handler = this.$events[name];
+
+  if (!handler) {
+    return false;
+  }
+
+  var args = [].slice.call(arguments, 1);
+
+  if ('function' == typeof handler) {
+    handler.apply(this, args);
+  } else if (isArray(handler)) {
+    var listeners = handler.slice();
+
+    for (var i = 0, l = listeners.length; i < l; i++) {
+      listeners[i].apply(this, args);
+    }
+  } else {
+    return false;
+  }
+
+  return true;
+};
\ No newline at end of file