78 lines
2.2 KiB
JavaScript
78 lines
2.2 KiB
JavaScript
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'use strict';
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var PromiseA = require('bluebird').Promise;
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var fs = PromiseA.promisifyAll(require('fs'));
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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.new) {
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options.new = 'new';
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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.new === options.bak) {
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throw new Error("'new' and 'bak' suffixes cannot be the same... duh");
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}
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var newnamefn = options.newnamefn || function (pathname) {
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return pathname + '.' + options.new;
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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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var namefn = options.namefn || function (pathname) {
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return pathname;
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};
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var sfs = {
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writeFile: function (filename, data, options) {
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//console.log(newnamefn(filename));
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return fs.writeFileAsync(newnamefn(filename), data, options).then(function () {
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//console.log(namefn(filename));
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return sfs.commit(namefn(filename));
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});
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}
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, commit: function (filename) {
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// this may not exist
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return fs.unlinkAsync(baknamefn(filename)).then(noop, noop).then(function () {
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// this may not exist
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//console.log(namefn(filename), '->', baknamefn(filename));
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return fs.renameAsync(namefn(filename), baknamefn(filename)).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(newnamefn(filename), '->', namefn(filename));
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return fs.renameAsync(newnamefn(filename), namefn(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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, revert: function (filename) {
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return new PromiseA(function (resolve, reject) {
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var reader = fs.createReadStream(baknamefn(filename));
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var writer = fs.createWriteStream(namefn(filename));
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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', resolve);
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});
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}
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};
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return sfs;
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}
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module.exports.create = create;
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