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var async = require('./async.js'); // API module.exports = { iterator: wrapIterator, callback: wrapCallback }; /** * Wraps iterators with long signature * * @this ReadableAsyncKit# * @param {function} iterator - function to wrap * @returns {function} - wrapped function */ function wrapIterator(iterator) { var stream = this; return function(item, key, cb) { var aborter , wrappedCb = async(wrapIteratorCallback.call(stream, cb, key)) ; stream.jobs[key] = wrappedCb; // it's either shortcut (item, cb) if (iterator.length == 2) { aborter = iterator(item, wrappedCb); } // or long format (item, key, cb) else { aborter = iterator(item, key, wrappedCb); } return aborter; }; } /** * Wraps provided callback function * allowing to execute snitch function before * real callback * * @this ReadableAsyncKit# * @param {function} callback - function to wrap * @returns {function} - wrapped function */ function wrapCallback(callback) { var stream = this; var wrapped = function(error, result) { return finisher.call(stream, error, result, callback); }; return wrapped; } /** * Wraps provided iterator callback function * makes sure snitch only called once, * but passes secondary calls to the original callback * * @this ReadableAsyncKit# * @param {function} callback - callback to wrap * @param {number|string} key - iteration key * @returns {function} wrapped callback */ function wrapIteratorCallback(callback, key) { var stream = this; return function(error, output) { // don't repeat yourself if (!(key in stream.jobs)) { callback(error, output); return; } // clean up jobs delete stream.jobs[key]; return streamer.call(stream, error, {key: key, value: output}, callback); }; } /** * Stream wrapper for iterator callback * * @this ReadableAsyncKit# * @param {mixed} error - error response * @param {mixed} output - iterator output * @param {function} callback - callback that expects iterator results */ function streamer(error, output, callback) { if (error && !this.error) { this.error = error; this.pause(); this.emit('error', error); // send back value only, as expected callback(error, output && output.value); return; } // stream stuff this.push(output); // back to original track // send back value only, as expected callback(error, output && output.value); } /** * Stream wrapper for finishing callback * * @this ReadableAsyncKit# * @param {mixed} error - error response * @param {mixed} output - iterator output * @param {function} callback - callback that expects final results */ function finisher(error, output, callback) { // signal end of the stream // only for successfully finished streams if (!error) { this.push(null); } // back to original track callback(error, output); }