119 rivejä
3.3 KiB
JavaScript
119 rivejä
3.3 KiB
JavaScript
'use strict';
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var PromiseA;
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try {
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PromiseA = require('bluebird');
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} catch(e) {
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PromiseA = global.Promise;
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}
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var util = require('util');
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var promisify = util.promisify || PromiseA.promisify;
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if (!PromiseA || !promisify) {
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throw new Error("DON'T PANIC. Everything is A-OK."
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+ " However, you're on a really old version of node. All you need to do is `npm install --save bluebird`"
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+ " (in your project directory, which is probably '" + require('path').dirname(require.main.filename) + "')"
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+ " and everything will work just fine.");
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}
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var fs = require('fs');
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var writeFileAsync = promisify(fs.writeFile);
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var unlinkAsync = promisify(fs.unlink);
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var renameAsync = promisify(fs.rename);
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var crypto = require('crypto');
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function noop() {
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}
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function create(options) {
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if (!options) {
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options = {};
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}
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if (!options.tmp) {
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options.tmp = 'tmp';
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}
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if (!options.bak) {
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options.bak = 'bak';
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}
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if (options.tmp === options.bak) {
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throw new Error("'tmp' and 'bak' suffixes cannot be the same... duh");
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}
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var tmpnamefn = options.tmpnamefn || function (pathname) {
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return pathname + '.' + crypto.randomBytes(8).toString('hex') + '.' + options.tmp;
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};
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var baknamefn = options.baknamefn || function (pathname) {
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return pathname + '.' + options.bak;
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};
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/*
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var namefn = options.namefn || function (pathname) {
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return pathname;
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};
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*/
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var sfs = {
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writeFileAsync: function (filename, data, options) {
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return sfs.stage(filename, data, options).then(function (tmpname) {
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//console.log(filename);
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return sfs.commit(tmpname, filename);
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});
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}
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, stageAsync: function (filename, data, options) {
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var tmpname = tmpnamefn(filename);
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//console.log(tmpname);
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return writeFileAsync(tmpname, data, options).then(function () {
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return tmpname;
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});
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}
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, commitAsync: function (tmpname, filename) {
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var bakname = baknamefn(filename);
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// this may not exist
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return unlinkAsync(bakname).then(noop, noop).then(function () {
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// this may not exist
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//console.log(namefn(filename), '->', bakname);
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return renameAsync(filename, bakname).then(function () {
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//console.log('created bak');
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}, noop);
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}).then(function () {
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// this must be successful
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//console.log(filename, '->', filename);
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return renameAsync(tmpname, filename).then(noop, function (err) {
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//console.error(err);
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return sfs.revert(filename).then(function () {
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return PromiseA.reject(err);
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});
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});
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});
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}
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, revertAsync: function (filename) {
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return new PromiseA(function (resolve, reject) {
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var bakname = baknamefn(filename);
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var tmpname = tmpnamefn(filename);
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var reader = fs.createReadStream(bakname);
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var writer = fs.createWriteStream(tmpname);
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reader.on('error', reject);
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writer.on('error', reject);
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reader.pipe(writer);
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writer.on('close', function () {
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sfs.commit(tmpname, filename).then(resolve, reject);
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});
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});
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}
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, tmpnamefn: tmpnamefn
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, baknamefn: baknamefn
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, create: create
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};
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sfs.writeFile = sfs.writeFileAsync;
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sfs.stage = sfs.stageAsync;
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sfs.commit = sfs.commitAsync;
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sfs.revert = sfs.revertAsync;
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return sfs;
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}
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module.exports = create();
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