/snap/node/11691/lib/node_modules/npm/node_modules/tar/dist/esm
Edit: /snap/node/11691/lib/node_modules/npm/node_modules/tar/dist/esm/path-reservations.js (5447B)
// A path exclusive reservation system
// reserve([list, of, paths], fn)
// When the fn is first in line for all its paths, it
// is called with a cb that clears the reservation.
//
// Used by async unpack to avoid clobbering paths in use,
// while still allowing maximal safe parallelization.
import { join } from 'node:path';
import { normalizeUnicode } from './normalize-unicode.js';
import { stripTrailingSlashes } from './strip-trailing-slashes.js';
const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform;
const isWindows = platform === 'win32';
// return a set of parent dirs for a given path
// '/a/b/c/d' -> ['/', '/a', '/a/b', '/a/b/c', '/a/b/c/d']
const getDirs = (path) => {
const dirs = path
.split('/')
.slice(0, -1)
.reduce((set, path) => {
const s = set[set.length - 1];
if (s !== undefined) {
path = join(s, path);
}
set.push(path || '/');
return set;
}, []);
return dirs;
};
export class PathReservations {
// path => [function or Set]
// A Set object means a directory reservation
// A fn is a direct reservation on that path
#queues = new Map();
// fn => {paths:[path,...], dirs:[path, ...]}
#reservations = new Map();
// functions currently running
#running = new Set();
reserve(paths, fn) {
paths =
isWindows ?
['win32 parallelization disabled']
: paths.map(p => {
// don't need normPath, because we skip this entirely for windows
return stripTrailingSlashes(join(normalizeUnicode(p)));
});
const dirs = new Set(paths.map(path => getDirs(path)).reduce((a, b) => a.concat(b)));
this.#reservations.set(fn, { dirs, paths });
for (const p of paths) {
const q = this.#queues.get(p);
if (!q) {
this.#queues.set(p, [fn]);
}
else {
q.push(fn);
}
}
for (const dir of dirs) {
const q = this.#queues.get(dir);
if (!q) {
this.#queues.set(dir, [new Set([fn])]);
}
else {
const l = q[q.length - 1];
if (l instanceof Set) {
l.add(fn);
}
else {
q.push(new Set([fn]));
}
}
}
return this.#run(fn);
}
// return the queues for each path the function cares about
// fn => {paths, dirs}
#getQueues(fn) {
const res = this.#reservations.get(fn);
/* c8 ignore start */
if (!res) {
throw new Error('function does not have any path reservations');
}
/* c8 ignore stop */
return {
paths: res.paths.map((path) => this.#queues.get(path)),
dirs: [...res.dirs].map(path => this.#queues.get(path)),
};
}
// check if fn is first in line for all its paths, and is
// included in the first set for all its dir queues
check(fn) {
const { paths, dirs } = this.#getQueues(fn);
return (paths.every(q => q && q[0] === fn) &&
dirs.every(q => q && q[0] instanceof Set && q[0].has(fn)));
}
// run the function if it's first in line and not already running
#run(fn) {
if (this.#running.has(fn) || !this.check(fn)) {
return false;
}
this.#running.add(fn);
fn(() => this.#clear(fn));
return true;
}
#clear(fn) {
if (!this.#running.has(fn)) {
return false;
}
const res = this.#reservations.get(fn);
/* c8 ignore start */
if (!res) {
throw new Error('invalid reservation');
}
/* c8 ignore stop */
const { paths, dirs } = res;
const next = new Set();
for (const path of paths) {
const q = this.#queues.get(path);
/* c8 ignore start */
if (!q || q?.[0] !== fn) {
continue;
}
/* c8 ignore stop */
const q0 = q[1];
if (!q0) {
this.#queues.delete(path);
continue;
}
q.shift();
if (typeof q0 === 'function') {
next.add(q0);
}
else {
for (const f of q0) {
next.add(f);
}
}
}
for (const dir of dirs) {
const q = this.#queues.get(dir);
const q0 = q?.[0];
/* c8 ignore next - type safety only */
if (!q || !(q0 instanceof Set))
continue;
if (q0.size === 1 && q.length === 1) {
this.#queues.delete(dir);
continue;
}
else if (q0.size === 1) {
q.shift();
// next one must be a function,
// or else the Set would've been reused
const n = q[0];
if (typeof n === 'function') {
next.add(n);
}
}
else {
q0.delete(fn);
}
}
this.#running.delete(fn);
next.forEach(fn => this.#run(fn));
return true;
}
}
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