ddv-restful-api/events/index.js

ddv-restful-api

// 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.

'use strict'

var spliceOne

function EventEmitter () {
  EventEmitter.init.call(this)
}
module.exports = EventEmitter

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

EventEmitter.usingDomains = false

EventEmitter.prototype._events = undefined
EventEmitter.prototype._eventsCount = 0
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.
var defaultMaxListeners = 10

var errors

function lazyErrors () {
  if (errors === undefined) {
    errors = {}
  }
  return errors
}

function checkListener (listener) {
  if (typeof listener !== 'function') {
    const errors = lazyErrors()
    throw new errors.ERR_INVALID_ARG_TYPE('listener', 'Function', listener)
  }
}

Object.defineProperty(EventEmitter, 'defaultMaxListeners', {
  enumerable: true,
  get: function () {
    return defaultMaxListeners
  },
  set: function (arg) {
    if (typeof arg !== 'number' || arg < 0 || Number.isNaN(arg)) {
      const errors = lazyErrors()
      throw new errors.ERR_OUT_OF_RANGE('defaultMaxListeners',
        'a non-negative number',
        arg)
    }
    defaultMaxListeners = arg
  }
})

EventEmitter.init = function () {
  if (this._events === undefined ||
    this._events === Object.getPrototypeOf(this)._events) {
    this._events = Object.create(null)
    this._eventsCount = 0
  }

  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 (typeof n !== 'number' || n < 0 || Number.isNaN(n)) {
    const errors = lazyErrors()
    throw new errors.ERR_OUT_OF_RANGE('n', 'a non-negative number', n)
  }
  this._maxListeners = n
  return this
}

function _getMaxListeners (that) {
  if (that._maxListeners === undefined) {
    return EventEmitter.defaultMaxListeners
  }
  return that._maxListeners
}

EventEmitter.prototype.getMaxListeners = function getMaxListeners () {
  return _getMaxListeners(this)
}

// Returns the length and line number of the first sequence of `a` that fully
// appears in `b` with a length of at least 4.
function identicalSequenceRange (a, b) {
  for (var i = 0; i < a.length - 3; i++) {
    // Find the first entry of b that matches the current entry of a.
    const pos = b.indexOf(a[i])
    if (pos !== -1) {
      const rest = b.length - pos
      if (rest > 3) {
        let len = 1
        const maxLen = Math.min(a.length - i, rest)
        // Count the number of consecutive entries.
        while (maxLen > len && a[i + len] === b[pos + len]) {
          len++
        }
        if (len > 3) {
          return [len, i]
        }
      }
    }
  }

  return [0, 0]
}

function enhanceStackTrace (err, own) {
  const sep = '\nEmitted \'error\' event at:\n'

  const errStack = err.stack.split('\n').slice(1)
  const ownStack = own.stack.split('\n').slice(1)

  const [len, off] = identicalSequenceRange(ownStack, errStack)
  if (len > 0) {
    ownStack.splice(off + 1, len - 2,
      '    [... lines matching original stack trace ...]')
  }
  // Do this last, because it is the only operation with side effects.
  err.stack = err.stack + sep + ownStack.join('\n')
}

EventEmitter.prototype.emit = function emit (type, ...args) {
  let doError = (type === 'error')

  const events = this._events
  if (events !== undefined) {
    doError = (doError && events.error === undefined)
  } else if (!doError) {
    return false
  }

  // If there is no 'error' event listener then throw.
  if (doError) {
    let er
    if (args.length > 0) {
      er = args[0]
    }
    throw er // Unhandled 'error' event
  }

  const handler = events[type]

  if (handler === undefined) {
    return false
  }

  if (typeof handler === 'function') {
    Reflect.apply(handler, this, args)
  } else {
    const len = handler.length
    const listeners = arrayClone(handler, len)
    for (var i = 0; i < len; ++i) {
      Reflect.apply(listeners[i], this, args)
    }
  }

  return true
}

function _addListener (target, type, listener, prepend) {
  var m
  var events
  var existing

  checkListener(listener)

  events = target._events
  if (events === undefined) {
    events = target._events = Object.create(null)
    target._eventsCount = 0
  } else {
    // To avoid recursion in the case that type === "newListener"! Before
    // adding it to the listeners, first emit "newListener".
    if (events.newListener !== undefined) {
      target.emit('newListener', type,
        listener.listener ? listener.listener : listener)

      // Re-assign `events` because a newListener handler could have caused the
      // this._events to be assigned to a new object
      events = target._events
    }
    existing = events[type]
  }

  if (existing === undefined) {
    // Optimize the case of one listener. Don't need the extra array object.
    events[type] = listener
    ++target._eventsCount
  } else {
    if (typeof existing === 'function') {
      // Adding the second element, need to change to array.
      existing = events[type] =
        prepend ? [listener, existing] : [existing, listener]
      // If we've already got an array, just append.
    } else if (prepend) {
      existing.unshift(listener)
    } else {
      existing.push(listener)
    }

    // Check for listener leak
    m = _getMaxListeners(target)
    if (m > 0 && existing.length > m && !existing.warned) {
      existing.warned = true
      // No error code for this since it is a Warning
      // eslint-disable-next-line no-restricted-syntax
      const w = new Error('Possible EventEmitter memory leak detected. ' +
        `${existing.length} ${String(type)} listeners ` +
        'added. Use emitter.setMaxListeners() to ' +
        'increase limit')
      w.name = 'MaxListenersExceededWarning'
      w.emitter = target
      w.type = type
      w.count = existing.length
      process.emitWarning(w)
    }
  }

  return target
}

EventEmitter.prototype.addListener = function addListener (type, listener) {
  return _addListener(this, type, listener, false)
}

EventEmitter.prototype.on = EventEmitter.prototype.addListener

EventEmitter.prototype.prependListener =
  function prependListener (type, listener) {
    return _addListener(this, type, listener, true)
  }

function onceWrapper (...args) {
  if (!this.fired) {
    this.target.removeListener(this.type, this.wrapFn)
    this.fired = true
    Reflect.apply(this.listener, this.target, args)
  }
}

function _onceWrap (target, type, listener) {
  var state = {
    fired: false,
    wrapFn: undefined,
    target,
    type,
    listener
  }
  var wrapped = onceWrapper.bind(state)
  wrapped.listener = listener
  state.wrapFn = wrapped
  return wrapped
}

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

  this.on(type, _onceWrap(this, type, listener))
  return this
}

EventEmitter.prototype.prependOnceListener =
  function prependOnceListener (type, listener) {
    checkListener(listener)

    this.prependListener(type, _onceWrap(this, type, listener))
    return this
  }

// Emits a 'removeListener' event if and only if the listener was removed.
EventEmitter.prototype.removeListener =
  function removeListener (type, listener) {
    var list, events, position, i, originalListener

    checkListener(listener)

    events = this._events
    if (events === undefined) {
      return this
    }

    list = events[type]
    if (list === undefined) {
      return this
    }

    if (list === listener || list.listener === listener) {
      if (--this._eventsCount === 0) {
        this._events = Object.create(null)
      } else {
        delete events[type]
        if (events.removeListener) {
          this.emit('removeListener', type, list.listener || listener)
        }
      }
    } else if (typeof list !== 'function') {
      position = -1

      for (i = list.length - 1; i >= 0; i--) {
        if (list[i] === listener || list[i].listener === listener) {
          originalListener = list[i].listener
          position = i
          break
        }
      }

      if (position < 0) {
        return this
      }

      if (position === 0) {
        list.shift()
      } else {
        if (spliceOne === undefined) {
          spliceOne = function spliceOne (list, index) {
            for (; index + 1 < list.length; index++)
              {list[index] = list[index + 1];}
            list.pop()
          }
        }
        spliceOne(list, position)
      }

      if (list.length === 1) {
        events[type] = list[0]
      }

      if (events.removeListener !== undefined) {
        this.emit('removeListener', type, originalListener || listener)
      }
    }

    return this
  }

EventEmitter.prototype.off = EventEmitter.prototype.removeListener

EventEmitter.prototype.removeAllListeners =
  function removeAllListeners (type) {
    var listeners, events, i

    events = this._events
    if (events === undefined) {
      return this
    }

    // not listening for removeListener, no need to emit
    if (events.removeListener === undefined) {
      if (arguments.length === 0) {
        this._events = Object.create(null)
        this._eventsCount = 0
      } else if (events[type] !== undefined) {
        if (--this._eventsCount === 0) {
          this._events = Object.create(null)
        } else {
          delete events[type]
        }
      }
      return this
    }

    // Emit removeListener for all listeners on all events
    if (arguments.length === 0) {
      var keys = Object.keys(events)
      var key
      for (i = 0; i < keys.length; ++i) {
        key = keys[i]
        if (key === 'removeListener') continue
        this.removeAllListeners(key)
      }
      this.removeAllListeners('removeListener')
      this._events = Object.create(null)
      this._eventsCount = 0
      return this
    }

    listeners = events[type]

    if (typeof listeners === 'function') {
      this.removeListener(type, listeners)
    } else if (listeners !== undefined) {
      // LIFO order
      for (i = listeners.length - 1; i >= 0; i--) {
        this.removeListener(type, listeners[i])
      }
    }

    return this
  }

function _listeners (target, type, unwrap) {
  const events = target._events

  if (events === undefined) {
    return []
  }

  const evlistener = events[type]
  if (evlistener === undefined) {
    return []
  }

  if (typeof evlistener === 'function') {
    return unwrap ? [evlistener.listener || evlistener] : [evlistener]
  }

  return unwrap
    ? unwrapListeners(evlistener) : arrayClone(evlistener, evlistener.length)
}

EventEmitter.prototype.listeners = function listeners (type) {
  return _listeners(this, type, true)
}

EventEmitter.prototype.rawListeners = function rawListeners (type) {
  return _listeners(this, type, false)
}

EventEmitter.listenerCount = function (emitter, type) {
  if (typeof emitter.listenerCount === 'function') {
    return emitter.listenerCount(type)
  } else {
    return listenerCount.call(emitter, type)
  }
}

EventEmitter.prototype.listenerCount = listenerCount

function listenerCount (type) {
  const events = this._events

  if (events !== undefined) {
    const evlistener = events[type]

    if (typeof evlistener === 'function') {
      return 1
    } else if (evlistener !== undefined) {
      return evlistener.length
    }
  }

  return 0
}

EventEmitter.prototype.eventNames = function eventNames () {
  return this._eventsCount > 0 ? Reflect.ownKeys(this._events) : []
}

function arrayClone (arr, n) {
  var copy = new Array(n)
  for (var i = 0; i < n; ++i) {
    copy[i] = arr[i]
  }
  return copy
}

function unwrapListeners (arr) {
  const ret = new Array(arr.length)
  for (var i = 0; i < ret.length; ++i) {
    ret[i] = arr[i].listener || arr[i]
  }
  return ret
}