var async = require('./async.js')
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, abort = require('./abort.js')
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;
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// API
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module.exports = iterate;
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/**
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* Iterates over each job object
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*
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* @param {array|object} list - array or object (named list) to iterate over
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* @param {function} iterator - iterator to run
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* @param {object} state - current job status
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* @param {function} callback - invoked when all elements processed
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*/
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function iterate(list, iterator, state, callback)
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{
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// store current index
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var key = state['keyedList'] ? state['keyedList'][state.index] : state.index;
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state.jobs[key] = runJob(iterator, key, list[key], function(error, output)
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{
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// don't repeat yourself
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// skip secondary callbacks
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if (!(key in state.jobs))
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{
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return;
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}
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// clean up jobs
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delete state.jobs[key];
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if (error)
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{
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// don't process rest of the results
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// stop still active jobs
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// and reset the list
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abort(state);
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}
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else
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{
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state.results[key] = output;
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}
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// return salvaged results
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callback(error, state.results);
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});
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}
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/**
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* Runs iterator over provided job element
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*
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* @param {function} iterator - iterator to invoke
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* @param {string|number} key - key/index of the element in the list of jobs
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* @param {mixed} item - job description
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* @param {function} callback - invoked after iterator is done with the job
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* @returns {function|mixed} - job abort function or something else
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*/
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function runJob(iterator, key, item, callback)
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{
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var aborter;
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// allow shortcut if iterator expects only two arguments
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if (iterator.length == 2)
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{
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aborter = iterator(item, async(callback));
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}
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// otherwise go with full three arguments
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else
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{
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aborter = iterator(item, key, async(callback));
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}
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return aborter;
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}
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