68 lines
2.3 KiB
JavaScript
68 lines
2.3 KiB
JavaScript
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'use strict';
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const fs = require('fs');
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const path = require('path');
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const { promisify } = require('util');
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const { cppdb } = require('../util');
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const fsAccess = promisify(fs.access);
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module.exports = async function backup(filename, options) {
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if (options == null) options = {};
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// Validate arguments
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if (typeof filename !== 'string') throw new TypeError('Expected first argument to be a string');
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if (typeof options !== 'object') throw new TypeError('Expected second argument to be an options object');
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// Interpret options
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filename = filename.trim();
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const attachedName = 'attached' in options ? options.attached : 'main';
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const handler = 'progress' in options ? options.progress : null;
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// Validate interpreted options
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if (!filename) throw new TypeError('Backup filename cannot be an empty string');
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if (filename === ':memory:') throw new TypeError('Invalid backup filename ":memory:"');
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if (typeof attachedName !== 'string') throw new TypeError('Expected the "attached" option to be a string');
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if (!attachedName) throw new TypeError('The "attached" option cannot be an empty string');
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if (handler != null && typeof handler !== 'function') throw new TypeError('Expected the "progress" option to be a function');
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// Make sure the specified directory exists
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await fsAccess(path.dirname(filename)).catch(() => {
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throw new TypeError('Cannot save backup because the directory does not exist');
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});
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const isNewFile = await fsAccess(filename).then(() => false, () => true);
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return runBackup(this[cppdb].backup(this, attachedName, filename, isNewFile), handler || null);
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};
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const runBackup = (backup, handler) => {
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let rate = 0;
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let useDefault = true;
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return new Promise((resolve, reject) => {
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setImmediate(function step() {
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try {
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const progress = backup.transfer(rate);
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if (!progress.remainingPages) {
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backup.close();
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resolve(progress);
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return;
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}
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if (useDefault) {
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useDefault = false;
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rate = 100;
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}
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if (handler) {
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const ret = handler(progress);
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if (ret !== undefined) {
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if (typeof ret === 'number' && ret === ret) rate = Math.max(0, Math.min(0x7fffffff, Math.round(ret)));
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else throw new TypeError('Expected progress callback to return a number or undefined');
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}
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}
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setImmediate(step);
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} catch (err) {
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backup.close();
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reject(err);
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}
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});
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});
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};
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