mirror of https://github.com/seald/nedb
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55 lines
1.8 KiB
55 lines
1.8 KiB
var crypto = require('crypto')
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, path = require('path')
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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 (less than 1/1,000,000) for the length to be less than len
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* (il the base64 conversion yields too many pluses and slashes) but
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* that's not an issue here
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* The probability of a collision is extremely small (need 3*10^12 documents to have one chance in a million of a collision)
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* See http://en.wikipedia.org/wiki/Birthday_problem
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*/
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function uid (len) {
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return crypto.randomBytes(Math.ceil(Math.max(8, len * 2)))
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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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* Return the path the datafile if the given filename is relative to the directory where Node Webkit stores
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* data for this application. Probably the best place to store data
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*/
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function getNWAppFilename (appName, relativeFilename) {
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var home;
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switch (process.platform) {
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case 'win32':
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case 'win64':
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home = process.env.LOCALAPPDATA || process.env.APPDATA;
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if (!home) { throw "Couldn't find the base application data folder"; }
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home = path.join(home, appName);
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break;
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case 'darwin':
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home = process.env.HOME;
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if (!home) { throw "Couldn't find the base application data directory"; }
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home = path.join(home, 'Library', 'Application Support', appName);
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break;
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case 'linux':
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home = process.env.HOME;
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if (!home) { throw "Couldn't find the base application data directory"; }
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home = path.join(home, '.config', appName);
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break;
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default:
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throw "Can't use the Node Webkit relative path for platform " + process.platform;
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break;
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}
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return path.join(home, 'nedb-data', relativeFilename);
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}
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module.exports.uid = uid;
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module.exports.getNWAppFilename = getNWAppFilename;
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