@alinex/datastore/lib/protocol/file.js

Read, work and write data structures from and to differents locations and formats.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.modified = exports.save = exports.load = void 0;
const fs_1 = require("fs");
const debug_1 = require("debug");
const debug = debug_1.default('datastore:protocol:file');
const load = async function (parsedUri, options = {}) {
    if (!parsedUri.pathname)
        return Promise.reject(`No pathname given in ${parsedUri.href}`);
    debug(`loading ${parsedUri.pathname}`);
    const meta = { path: parsedUri.pathname };
    fs_1.promises
        .stat(parsedUri.pathname)
        .then(stat => {
        meta.stats = stat;
    })
        .catch(e => undefined);
    if (options.tail) {
        let lines = 0;
        const bufferSize = 4096;
        let soFar = Buffer.from('');
        let data = Buffer.from('');
        const fd = await fs_1.promises.open(parsedUri.pathname, 'r');
        let position = meta.stats.size;
        while (position && lines < options.tail) {
            let buffer = Buffer.alloc(bufferSize);
            var length = Math.min(bufferSize, position);
            position = position - length;
            fs_1.readSync(fd.fd, buffer, 0, length, position);
            soFar = Buffer.concat([buffer, soFar]);
            let pos = soFar.byteLength;
            do {
                pos = soFar.lastIndexOf('\n', pos - 1);
                lines++;
            } while (pos !== -1 && lines < options.tail);
            data = Buffer.concat([soFar.slice(pos), data]);
            soFar = soFar.slice(0, pos);
        }
        fd.close();
        return Promise.resolve([data.slice(1), meta]);
    }
    return fs_1.promises.readFile(parsedUri.pathname).then(data => [data, meta]);
};
exports.load = load;
const save = function (parsedUri, buffer, options) {
    if (!parsedUri.pathname)
        return Promise.reject(`No pathname given in ${parsedUri.href}`);
    debug(`storing to ${parsedUri.pathname}`);
    return fs_1.promises.writeFile(parsedUri.pathname, buffer);
};
exports.save = save;
const modified = async function (parsedUri, options) {
    if (!parsedUri.pathname)
        return Promise.reject(`No pathname given in ${parsedUri.href}`);
    debug(`last modification check ${parsedUri.pathname}`);
    const fileinfo = await fs_1.promises.stat(parsedUri.pathname);
    return Promise.resolve(fileinfo.mtime);
};
exports.modified = modified;
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