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82 lines
1.8 KiB
82 lines
1.8 KiB
var fs = require('fs')
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, crypto = require('crypto')
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;
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/**
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* Check if directory exists and create it on the fly if it is not the case
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* TODO: make recursive
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*/
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function ensureDirectoryExists (dir, cb) {
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var callback = cb || function () {};
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fs.exists(dir, function (exists) {
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if (exists) {
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return callback();
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} else {
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fs.mkdir(dir, '0777', callback);
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}
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});
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}
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/**
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* Return a random alphanumerical string of length len
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* There is a very small probability for the length to be less than len
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* (il the base64 conversion yields to many pluses and slashes) but
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* that's not an issue here
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*/
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function uid (len) {
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return crypto.randomBytes(Math.ceil(len * 5 / 4))
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.toString('base64')
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.replace(/[+\/]/g, '')
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.slice(0, len);
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}
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/**
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* Deep copy an DB object
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* TODO: Put in serialization/deserialization and tackle all cases
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*/
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function deepCopy (obj) {
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var res;
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if (typeof obj === 'boolean' || typeof obj === 'number' || typeof obj === 'string') {
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return obj;
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}
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if (typeof obj === 'object') {
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res = {};
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Object.keys(obj).forEach(function (k) {
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res[k] = deepCopy(obj[k]);
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});
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return res;
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}
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return undefined; // For now everything else is undefined. We should probably throw an error instead
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}
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/**
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* Return an array with the numbers from 0 to n-1, in a random order
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* Used in the benchmarks
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*/
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function getRandomArray (n) {
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var res, next;
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if (n === 0) { return []; }
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if (n === 1) { return [0]; }
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res = getRandomArray(n - 1);
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next = Math.floor(Math.random() * n);
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res.splice(next, 0, n - 1); // Add n-1 at a random position in the array
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return res;
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}
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module.exports.ensureDirectoryExists = ensureDirectoryExists;
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module.exports.uid = uid;
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module.exports.deepCopy = deepCopy;
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module.exports.getRandomArray = getRandomArray;
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