irc-block-tracker/dist/BaseBlockTracker.js

A block tracker for the Ir blockchain. Keeps track of the latest block.

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.BaseBlockTracker = f()}})(function(){var define,module,exports;return (function(){function r(e,n,t){function o(i,f){if(!n[i]){if(!e[i]){var c="function"==typeof require&&require;if(!f&&c)return c(i,!0);if(u)return u(i,!0);var a=new Error("Cannot find module '"+i+"'");throw a.code="MODULE_NOT_FOUND",a}var p=n[i]={exports:{}};e[i][0].call(p.exports,function(r){var n=e[i][1][r];return o(n||r)},p,p.exports,r,e,n,t)}return n[i].exports}for(var u="function"==typeof require&&require,i=0;i<t.length;i++)o(t[i]);return o}return r})()({1:[function(require,module,exports){
// 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.
//
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// 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.

function EventEmitter() {
  this._events = this._events || {};
  this._maxListeners = this._maxListeners || undefined;
}
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;

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

EventEmitter.prototype.emit = function(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') {
    if (!this._events.error ||
        (isObject(this._events.error) && !this._events.error.length)) {
      er = arguments[1];
      if (er instanceof Error) {
        throw er; // Unhandled 'error' event
      } else {
        // At least give some kind of context to the user
        var err = new Error('Uncaught, unspecified "error" event. (' + er + ')');
        err.context = er;
        throw err;
      }
    }
  }

  handler = this._events[type];

  if (isUndefined(handler))
    return false;

  if (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:
        args = Array.prototype.slice.call(arguments, 1);
        handler.apply(this, args);
    }
  } else if (isObject(handler)) {
    args = Array.prototype.slice.call(arguments, 1);
    listeners = handler.slice();
    len = listeners.length;
    for (i = 0; i < len; i++)
      listeners[i].apply(this, args);
  }

  return true;
};

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

  if (!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,
              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 (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 (isObject(this._events[type]) && !this._events[type].warned) {
    if (!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 listeners added. ' +
                    'Use emitter.setMaxListeners() to increase limit.',
                    this._events[type].length);
      if (typeof console.trace === 'function') {
        // not supported in IE 10
        console.trace();
      }
    }
  }

  return this;
};

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

EventEmitter.prototype.once = function(type, listener) {
  if (!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(type, listener) {
  var list, position, length, i;

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

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

  return this;
};

EventEmitter.prototype.listeners = function(type) {
  var ret;
  if (!this._events || !this._events[type])
    ret = [];
  else if (isFunction(this._events[type]))
    ret = [this._events[type]];
  else
    ret = this._events[type].slice();
  return ret;
};

EventEmitter.prototype.listenerCount = function(type) {
  if (this._events) {
    var evlistener = this._events[type];

    if (isFunction(evlistener))
      return 1;
    else if (evlistener)
      return evlistener.length;
  }
  return 0;
};

EventEmitter.listenerCount = function(emitter, type) {
  return emitter.listenerCount(type);
};

function isFunction(arg) {
  return typeof arg === 'function';
}

function isNumber(arg) {
  return typeof arg === 'number';
}

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}

function isUndefined(arg) {
  return arg === void 0;
}

},{}],2:[function(require,module,exports){
'use strict';

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

var _get = function get(object, property, receiver) { if (object === null) object = Function.prototype; var desc = Object.getOwnPropertyDescriptor(object, property); if (desc === undefined) { var parent = Object.getPrototypeOf(object); if (parent === null) { return undefined; } else { return get(parent, property, receiver); } } else if ("value" in desc) { return desc.value; } else { var getter = desc.get; if (getter === undefined) { return undefined; } return getter.call(receiver); } };

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

var EventEmitter = require('events');
var calculateSum = function calculateSum(accumulator, currentValue) {
  return accumulator + currentValue;
};
var blockTrackerEvents = ['sync', 'latest'];
var sec = 1000;

var BaseBlockTracker = function (_EventEmitter) {
  _inherits(BaseBlockTracker, _EventEmitter);

  // public
  function BaseBlockTracker() {
    var opts = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};

    _classCallCheck(this, BaseBlockTracker);

    // config
    var _this = _possibleConstructorReturn(this, (BaseBlockTracker.__proto__ || Object.getPrototypeOf(BaseBlockTracker)).call(this));

    _this._blockResetDuration = opts.blockResetDuration || 20 * sec;
    // state
    _this._blockResetTimeout = null;
    _this._currentBlock = null;
    _this._isRunning = false;
    // bind functions for internal use
    _this._onNewListener = _this._onNewListener.bind(_this);
    _this._onRemoveListener = _this._onRemoveListener.bind(_this);
    _this._resetCurrentBlock = _this._resetCurrentBlock.bind(_this);
    // listen for handler changes
    _this._setupInternalEvents();
    return _this;
  }

  _createClass(BaseBlockTracker, [{
    key: 'isRunning',
    value: function isRunning() {
      return this._isRunning;
    }
  }, {
    key: 'getCurrentBlock',
    value: function getCurrentBlock() {
      return this._currentBlock;
    }
  }, {
    key: 'getLatestBlock',
    value: async function getLatestBlock() {
      var _this2 = this;

      // return if available
      if (this._currentBlock) return this._currentBlock;
      // wait for a new latest block
      var latestBlock = await new Promise(function (resolve) {
        return _this2.once('latest', resolve);
      });
      // return newly set current block
      return latestBlock;
    }

    // dont allow module consumer to remove our internal event listeners

  }, {
    key: 'removeAllListeners',
    value: function removeAllListeners(eventName) {
      // perform default behavior, preserve fn arity
      if (eventName) {
        _get(BaseBlockTracker.prototype.__proto__ || Object.getPrototypeOf(BaseBlockTracker.prototype), 'removeAllListeners', this).call(this, eventName);
      } else {
        _get(BaseBlockTracker.prototype.__proto__ || Object.getPrototypeOf(BaseBlockTracker.prototype), 'removeAllListeners', this).call(this);
      }
      // re-add internal events
      this._setupInternalEvents();
      // trigger stop check just in case
      this._onRemoveListener();
    }

    //
    // to be implemented in subclass
    //

  }, {
    key: '_start',
    value: function _start() {
      // default behavior is noop
    }
  }, {
    key: '_end',
    value: function _end() {}
    // default behavior is noop


    //
    // private
    //

  }, {
    key: '_setupInternalEvents',
    value: function _setupInternalEvents() {
      // first remove listeners for idempotence
      this.removeListener('newListener', this._onNewListener);
      this.removeListener('removeListener', this._onRemoveListener);
      // then add them
      this.on('newListener', this._onNewListener);
      this.on('removeListener', this._onRemoveListener);
    }
  }, {
    key: '_onNewListener',
    value: function _onNewListener(eventName, handler) {
      // `newListener` is called *before* the listener is added
      if (!blockTrackerEvents.includes(eventName)) return;
      this._maybeStart();
    }
  }, {
    key: '_onRemoveListener',
    value: function _onRemoveListener(eventName, handler) {
      // `removeListener` is called *after* the listener is removed
      if (this._getBlockTrackerEventCount() > 0) return;
      this._maybeEnd();
    }
  }, {
    key: '_maybeStart',
    value: function _maybeStart() {
      if (this._isRunning) return;
      this._isRunning = true;
      // cancel setting latest block to stale
      this._cancelBlockResetTimeout();
      this._start();
    }
  }, {
    key: '_maybeEnd',
    value: function _maybeEnd() {
      if (!this._isRunning) return;
      this._isRunning = false;
      this._setupBlockResetTimeout();
      this._end();
    }
  }, {
    key: '_getBlockTrackerEventCount',
    value: function _getBlockTrackerEventCount() {
      var _this3 = this;

      return blockTrackerEvents.map(function (eventName) {
        return _this3.listenerCount(eventName);
      }).reduce(calculateSum);
    }
  }, {
    key: '_newPotentialLatest',
    value: function _newPotentialLatest(newBlock) {
      var currentBlock = this._currentBlock;
      // only update if blok number is higher
      if (currentBlock && hexToInt(newBlock) <= hexToInt(currentBlock)) return;
      this._setCurrentBlock(newBlock);
    }
  }, {
    key: '_setCurrentBlock',
    value: function _setCurrentBlock(newBlock) {
      var oldBlock = this._currentBlock;
      this._currentBlock = newBlock;
      this.emit('latest', newBlock);
      this.emit('sync', { oldBlock: oldBlock, newBlock: newBlock });
    }
  }, {
    key: '_setupBlockResetTimeout',
    value: function _setupBlockResetTimeout() {
      // clear any existing timeout
      this._cancelBlockResetTimeout();
      // clear latest block when stale
      this._blockResetTimeout = setTimeout(this._resetCurrentBlock, this._blockResetDuration);
      // nodejs - dont hold process open
      if (this._blockResetTimeout.unref) {
        this._blockResetTimeout.unref();
      }
    }
  }, {
    key: '_cancelBlockResetTimeout',
    value: function _cancelBlockResetTimeout() {
      clearTimeout(this._blockResetTimeout);
    }
  }, {
    key: '_resetCurrentBlock',
    value: function _resetCurrentBlock() {
      this._currentBlock = null;
    }
  }]);

  return BaseBlockTracker;
}(EventEmitter);

module.exports = BaseBlockTracker;

function hexToInt(hexInt) {
  return Number.parseInt(hexInt, 16);
}

},{"events":1}]},{},[2])(2)
});