strong-tie/inbound-calls

1var async = require('./async.js');2 3// API4module.exports = {5  iterator: wrapIterator,6  callback: wrapCallback7};8 9/**10 * Wraps iterators with long signature11 *12 * @this    ReadableAsyncKit#13 * @param   {function} iterator - function to wrap14 * @returns {function} - wrapped function15 */16function wrapIterator(iterator)17{18  var stream = this;19 20  return function(item, key, cb)21  {22    var aborter23      , wrappedCb = async(wrapIteratorCallback.call(stream, cb, key))24      ;25 26    stream.jobs[key] = wrappedCb;27 28    // it's either shortcut (item, cb)29    if (iterator.length == 2)30    {31      aborter = iterator(item, wrappedCb);32    }33    // or long format (item, key, cb)34    else35    {36      aborter = iterator(item, key, wrappedCb);37    }38 39    return aborter;40  };41}42 43/**44 * Wraps provided callback function45 * allowing to execute snitch function before46 * real callback47 *48 * @this    ReadableAsyncKit#49 * @param   {function} callback - function to wrap50 * @returns {function} - wrapped function51 */52function wrapCallback(callback)53{54  var stream = this;55 56  var wrapped = function(error, result)57  {58    return finisher.call(stream, error, result, callback);59  };60 61  return wrapped;62}63 64/**65 * Wraps provided iterator callback function66 * makes sure snitch only called once,67 * but passes secondary calls to the original callback68 *69 * @this    ReadableAsyncKit#70 * @param   {function} callback - callback to wrap71 * @param   {number|string} key - iteration key72 * @returns {function} wrapped callback73 */74function wrapIteratorCallback(callback, key)75{76  var stream = this;77 78  return function(error, output)79  {80    // don't repeat yourself81    if (!(key in stream.jobs))82    {83      callback(error, output);84      return;85    }86 87    // clean up jobs88    delete stream.jobs[key];89 90    return streamer.call(stream, error, {key: key, value: output}, callback);91  };92}93 94/**95 * Stream wrapper for iterator callback96 *97 * @this  ReadableAsyncKit#98 * @param {mixed} error - error response99 * @param {mixed} output - iterator output100 * @param {function} callback - callback that expects iterator results101 */102function streamer(error, output, callback)103{104  if (error && !this.error)105  {106    this.error = error;107    this.pause();108    this.emit('error', error);109    // send back value only, as expected110    callback(error, output && output.value);111    return;112  }113 114  // stream stuff115  this.push(output);116 117  // back to original track118  // send back value only, as expected119  callback(error, output && output.value);120}121 122/**123 * Stream wrapper for finishing callback124 *125 * @this  ReadableAsyncKit#126 * @param {mixed} error - error response127 * @param {mixed} output - iterator output128 * @param {function} callback - callback that expects final results129 */130function finisher(error, output, callback)131{132  // signal end of the stream133  // only for successfully finished streams134  if (!error)135  {136    this.push(null);137  }138 139  // back to original track140  callback(error, output);141}142