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garrytan
d93d61f7ba
Mechanical reformat only. Minified transpile output is byte-identical for 21 of 22 files; witness.ts differs only in three regex flag orders (/mi -> /im), which JavaScript canonicalizes. Source-text assertions over lib/cso now compare whitespace-insensitively with the same tokens.
60 lines
2.3 KiB
TypeScript
60 lines
2.3 KiB
TypeScript
import * as fs from 'node:fs';
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import { CsoError } from './contracts';
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/** Read one caller-supplied control file without following or blocking on a raced special file. */
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export function readBoundedStable(path: string, max: number, label: string): Buffer {
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let named: fs.Stats, fd: number | undefined;
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try {
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named = fs.lstatSync(path);
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} catch {
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throw new CsoError('MISSING_INPUT', `${label} does not exist`);
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}
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if (named.isSymbolicLink() || !named.isFile() || named.nlink !== 1 || named.size > max)
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throw new CsoError('MISSING_INPUT', `${label} must be one bounded regular file`);
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try {
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fd = fs.openSync(
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path,
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fs.constants.O_RDONLY | (fs.constants.O_NOFOLLOW ?? 0) | (fs.constants.O_NONBLOCK ?? 0),
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);
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const opened = fs.fstatSync(fd);
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if (
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!opened.isFile() ||
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opened.nlink !== 1 ||
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opened.dev !== named.dev ||
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opened.ino !== named.ino ||
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opened.mode !== named.mode ||
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opened.size !== named.size
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)
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throw new CsoError('SNAPSHOT_RACE', `${label} changed before it could be read`);
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const data = Buffer.alloc(max + 1);
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let bytes = 0,
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count = 0;
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while (bytes < data.length && (count = fs.readSync(fd, data, bytes, data.length - bytes, null)) > 0)
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bytes += count;
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const after = fs.fstatSync(fd),
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current = fs.lstatSync(path);
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if (bytes > max) throw new CsoError('MISSING_INPUT', `${label} exceeds the ${max}-byte limit`);
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if (
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!current.isFile() ||
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current.isSymbolicLink() ||
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current.nlink !== 1 ||
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current.dev !== opened.dev ||
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current.ino !== opened.ino ||
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current.mode !== opened.mode ||
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after.size !== opened.size ||
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after.mtimeMs !== opened.mtimeMs ||
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after.ctimeMs !== opened.ctimeMs
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)
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throw new CsoError('SNAPSHOT_RACE', `${label} changed while it was read`);
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return data.subarray(0, bytes);
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} catch (error) {
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if (error instanceof CsoError) throw error;
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const code = (error as NodeJS.ErrnoException).code;
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if (['ELOOP', 'ENOENT', 'ENOTDIR', 'ENXIO'].includes(code ?? ''))
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throw new CsoError('SNAPSHOT_RACE', `${label} changed before it could be opened`);
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throw new CsoError('MISSING_INPUT', `${label} is missing or unreadable`);
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} finally {
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if (fd !== undefined) fs.closeSync(fd);
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}
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}
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