// Copyright Joyent, Inc. and other Node contributors. // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the // “Software”), to deal in the Software without restriction, including // without limitation the rights to use, copy, modify, merge, publish, // distribute, sublicense, and/or sell copies of the Software, and to permit // persons to whom the Software is furnished to do so, subject to the // following conditions: // // The above copyright notice and this permission notice shall be included // in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN // NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE // USE OR OTHER DEALINGS IN THE SOFTWARE.

var util = require(‘util’);

function EventEmitter() {

EventEmitter.init.call(this);

} module.exports = EventEmitter;

// Backwards-compat with node 0.10.x EventEmitter.EventEmitter = EventEmitter;

EventEmitter.prototype._events = undefined; EventEmitter.prototype._maxListeners = undefined;

// By default EventEmitters will print a warning if more than 10 listeners are // added to it. This is a useful default which helps finding memory leaks. EventEmitter.defaultMaxListeners = 10;

EventEmitter.init = function() {

if (!this._events || this._events === Object.getPrototypeOf(this)._events)
  this._events = {};

this._maxListeners = this._maxListeners || undefined;

};

// Obviously not all Emitters should be limited to 10. This function allows // that to be increased. Set to zero for unlimited. EventEmitter.prototype.setMaxListeners = function setMaxListeners(n) {

if (!util.isNumber(n) || n < 0 || isNaN(n))
  throw TypeError('n must be a positive number');
this._maxListeners = n;
return this;

};

EventEmitter.prototype.emit = function emit(type) {

var er, handler, len, args, i, listeners;

if (!this._events)
  this._events = {};

// If there is no 'error' event listener then throw.
if (type === 'error' && !this._events.error) {
  er = arguments[1];
  if (er instanceof Error) {
    throw er; // Unhandled 'error' event
  } else {
    throw Error('Uncaught, unspecified "error" event.');
  }
  return false;
}

handler = this._events[type];

if (util.isUndefined(handler))
  return false;

if (util.isFunction(handler)) {
  switch (arguments.length) {
    // fast cases
    case 1:
      handler.call(this);
      break;
    case 2:
      handler.call(this, arguments[1]);
      break;
    case 3:
      handler.call(this, arguments[1], arguments[2]);
      break;
    // slower
    default:
      len = arguments.length;
      args = new Array(len - 1);
      for (i = 1; i < len; i++)
        args[i - 1] = arguments[i];
      handler.apply(this, args);
  }
} else if (util.isObject(handler)) {
  len = arguments.length;
  args = new Array(len - 1);
  for (i = 1; i < len; i++)
    args[i - 1] = arguments[i];

  listeners = handler.slice();
  len = listeners.length;
  for (i = 0; i < len; i++)
    listeners[i].apply(this, args);
}

return true;

};

EventEmitter.prototype.addListener = function addListener(type, listener) {

var m;

if (!util.isFunction(listener))
  throw TypeError('listener must be a function');

if (!this._events)
  this._events = {};

// To avoid recursion in the case that type === "newListener"! Before
// adding it to the listeners, first emit "newListener".
if (this._events.newListener)
  this.emit('newListener', type,
            util.isFunction(listener.listener) ?
            listener.listener : listener);

if (!this._events[type])
  // Optimize the case of one listener. Don't need the extra array object.
  this._events[type] = listener;
else if (util.isObject(this._events[type]))
  // If we've already got an array, just append.
  this._events[type].push(listener);
else
  // Adding the second element, need to change to array.
  this._events[type] = [this._events[type], listener];

// Check for listener leak
if (util.isObject(this._events[type]) && !this._events[type].warned) {
  var m;
  if (!util.isUndefined(this._maxListeners)) {
    m = this._maxListeners;
  } else {
    m = EventEmitter.defaultMaxListeners;
  }

  if (m && m > 0 && this._events[type].length > m) {
    this._events[type].warned = true;
    console.error('(node) warning: possible EventEmitter memory ' +
                  'leak detected. %d %s listeners added. ' +
                  'Use emitter.setMaxListeners() to increase limit.',
                  this._events[type].length, type);
    console.trace();
  }
}

return this;

};

EventEmitter.prototype.on = EventEmitter.prototype.addListener;

EventEmitter.prototype.once = function once(type, listener) {

if (!util.isFunction(listener))
  throw TypeError('listener must be a function');

var fired = false;

function g() {
  this.removeListener(type, g);

  if (!fired) {
    fired = true;
    listener.apply(this, arguments);
  }
}

g.listener = listener;
this.on(type, g);

return this;

};

// emits a ‘removeListener’ event iff the listener was removed EventEmitter.prototype.removeListener =

  function removeListener(type, listener) {
var list, position, length, i;

if (!util.isFunction(listener))
  throw TypeError('listener must be a function');

if (!this._events || !this._events[type])
  return this;

list = this._events[type];
length = list.length;
position = -1;

if (list === listener ||
    (util.isFunction(list.listener) && list.listener === listener)) {
  delete this._events[type];
  if (this._events.removeListener)
    this.emit('removeListener', type, listener);

} else if (util.isObject(list)) {
  for (i = length; i-- > 0;) {
    if (list[i] === listener ||
        (list[i].listener && list[i].listener === listener)) {
      position = i;
      break;
    }
  }

  if (position < 0)
    return this;

  if (list.length === 1) {
    list.length = 0;
    delete this._events[type];
  } else {
    list.splice(position, 1);
  }

  if (this._events.removeListener)
    this.emit('removeListener', type, listener);
}

return this;

};

EventEmitter.prototype.removeAllListeners =

  function removeAllListeners(type) {
var key, listeners;

if (!this._events)
  return this;

// not listening for removeListener, no need to emit
if (!this._events.removeListener) {
  if (arguments.length === 0)
    this._events = {};
  else if (this._events[type])
    delete this._events[type];
  return this;
}

// emit removeListener for all listeners on all events
if (arguments.length === 0) {
  for (key in this._events) {
    if (key === 'removeListener') continue;
    this.removeAllListeners(key);
  }
  this.removeAllListeners('removeListener');
  this._events = {};
  return this;
}

listeners = this._events[type];

if (util.isFunction(listeners)) {
  this.removeListener(type, listeners);
} else if (Array.isArray(listeners)) {
  // LIFO order
  while (listeners.length)
    this.removeListener(type, listeners[listeners.length - 1]);
}
delete this._events[type];

return this;

};

EventEmitter.prototype.listeners = function listeners(type) {

var ret;
if (!this._events || !this._events[type])
  ret = [];
else if (util.isFunction(this._events[type]))
  ret = [this._events[type]];
else
  ret = this._events[type].slice();
return ret;

};

EventEmitter.listenerCount = function(emitter, type) {

var ret;
if (!emitter._events || !emitter._events[type])
  ret = 0;
else if (util.isFunction(emitter._events[type]))
  ret = 1;
else
  ret = emitter._events[type].length;
return ret;

};