VulpesOS/gaia/apps/sms/lib/bridge/plugins/stream/service.js

!((define)=>{define((require,exports,module)=>{

/**
 * Mini Logger
 *
 * @type {Function}
 */

var debug = 0 ? function(arg1, ...args) {
  var type = `[${self.constructor.name}][${location.pathname}]`;
  console.log(`[ServiceStream]${type} - "${arg1}"`, ...args);
} : () => {};

module.exports = function(service) {
  debug('attaching plugin');

  service
    .method('_stream', onStream)
    .method('_streamcancel', onStreamCancel);

  service._streamHandlers = {};
  service._activeStreams = [];

  service.stream = function(name, fn) {
    debug('register stream', name);
    this._streamHandlers[name] = fn;
    return this;
  };

  function onStream(name, id, clientId, args) {
    debug('on stream open', name);
    var e = {
      preventDefault: () => e.defaultPrevented = true,
      arguments: arguments
    };

    // Allow other plugins to override default behaviour
    service.emit('before-stream', e);
    if (e.defaultPrevented) return;

    var fn = service._streamHandlers[name];
    if (!fn) throw error(1, name);

    var stream = new ServiceStream(id, service, clientId);
    service._activeStreams[id] = stream;

    // Always pass stream object as first
    // argument to simplify the process
    fn.apply(service, [stream].concat(args));
  }

  function onStreamCancel(id, reason) {
    debug('stream cancel');
    var stream = service._activeStreams[id];
    delete service._activeStreams[id];
    return stream.cancel(reason);
  }
};

/**
 * Writable Stream instance passed to the
 * `service.stream` implementation
 *
 * @param {Object} options
 * @param {String} options.id Stream ID used to sync client and service streams
 * @param {BroadcastChannel} options.channel Channel used to postMessage
 * @param {String} options.serviceId ID of the service
 * @param {String} options.clientId ID of client that should receive message
 */

function ServiceStream(streamId, service, clientId) {
  this.id = streamId;
  this.service = service;
  this.clientId = clientId;
  this.writable = true;
  debug('initialized');
}

/**
 * Prototype assigned to variable
 * to improve compression.
 *
 * @type {Object}
 */

var ServiceStreamPrototype = ServiceStream.prototype;

/**
 * Services that allows clients to
 * cancel the operation before it's
 * complete should override the
 * `stream.cancel` method.
 *
 * @param {*} [reason] Data sent from client about the cancellation
 * @returns {(Promise|*)}
 */

ServiceStreamPrototype.cancel = function(reason) {
  var err = new TypeError('service should implement stream.cancel()');
  return Promise.reject(err);
};

/**
 * Signal to client that action was
 * aborted during the process, this
 * should be used as a way to
 * communicate errors.
 *
 * @param {*} [data] Reason of failure
 * @returns {Promise}
 * @public
 */

ServiceStreamPrototype.abort = function(data) {
  debug('abort', data);
  this._post('abort', data);
  this.writable = false;
};

/**
 * Sends a chunk of data to the client.
 *
 * @param {*} data Chunk of data to be sent to client.
 * @returns {Promise}
 * @public
 */

ServiceStreamPrototype.write = function(data) {
  debug('write', data);
  this._post('write', data);
};

/**
 * Closes the stream, signals that
 * action was completed with success.
 *
 * According to whatwg streams spec,
 * WritableStream#close() doesn't send data.
 *
 * @returns {Promise}
 */

ServiceStreamPrototype.close = function() {
  debug('close');
  this._post('close');
  this.writable = false;
};

/**
 * Validate the current state and
 * call cancel on the target stream.
 *
 * Called by the Service when client
 * sends a 'streamcancel' message.
 *
 * @param {*} [reason] Reason for cancelation sent by the client
 * @returns {Promise}
 * @private
 */

ServiceStreamPrototype._cancel = function(reason) {
  debug('cancel', reason);
  return this.cancel(reason)
    .then(result => {
      this.writable = false;
      return result;
    });
};

/**
 * Validate the current state and post message to client.
 *
 * @param {String} type 'write', 'abort' or 'close'
 * @param {String} state 'writable', 'aborted' or 'closed'
 * @param {*} [data] Data to be sent to the client
 * @returns {Promise}
 * @private
 */

ServiceStreamPrototype._post = function(type, data) {
  debug('post', type, data, this.writable);
  if (!this.writable) return Promise.reject();
  this.service.broadcast('streamevent', {
    streamId: this.id,
    type: type,
    data: data
  }, [this.clientId]);
};

/**
 * Create new `Error` from registery.
 *
 * @param  {Number} id Error Id
 * @return {Error}
 * @private
 */
function error(id) {
  var args = [].slice.call(arguments, 1);
  return new Error({
    1: 'stream "' + args[0] + '" doesn\'t exist'
  }[id]);
}

});})((typeof define)[0]=='f'&&define.amd?define:((n,w)=>{return(typeof
module)[0]=='o'?c=>{c(require,exports,module);}:(c)=>{var m={exports:{}};
c(n=>w[n],m.exports,m);w[n]=m.exports;};})('streamService',this));