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1// A path exclusive reservation system2// reserve([list, of, paths], fn)3// When the fn is first in line for all its paths, it4// is called with a cb that clears the reservation.5//6// Used by async unpack to avoid clobbering paths in use,7// while still allowing maximal safe parallelization.8import { join } from 'node:path';9import { normalizeUnicode } from './normalize-unicode.js';10import { stripTrailingSlashes } from './strip-trailing-slashes.js';11const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform;12const isWindows = platform === 'win32';13// return a set of parent dirs for a given path14// '/a/b/c/d' -> ['/', '/a', '/a/b', '/a/b/c', '/a/b/c/d']15const getDirs = (path) => {16    const dirs = path17        .split('/')18        .slice(0, -1)19        .reduce((set, path) => {20        const s = set.at(-1);21        if (s !== undefined) {22            path = join(s, path);23        }24        set.push(path || '/');25        return set;26    }, []);27    return dirs;28};29export class PathReservations {30    // path => [function or Set]31    // A Set object means a directory reservation32    // A fn is a direct reservation on that path33    #queues = new Map();34    // fn => {paths:[path,...], dirs:[path, ...]}35    #reservations = new Map();36    // functions currently running37    #running = new Set();38    reserve(paths, fn) {39        paths =40            isWindows ?41                ['win32 parallelization disabled']42                : paths.map(p => {43                    // don't need normPath, because we skip this entirely for windows44                    return stripTrailingSlashes(join(normalizeUnicode(p)));45                });46        const dirs = new Set(paths.map(path => getDirs(path)).reduce((a, b) => a.concat(b)));47        this.#reservations.set(fn, { dirs, paths });48        for (const p of paths) {49            const q = this.#queues.get(p);50            if (!q) {51                this.#queues.set(p, [fn]);52            }53            else {54                q.push(fn);55            }56        }57        for (const dir of dirs) {58            const q = this.#queues.get(dir);59            if (!q) {60                this.#queues.set(dir, [new Set([fn])]);61            }62            else {63                const l = q.at(-1);64                if (l instanceof Set) {65                    l.add(fn);66                }67                else {68                    q.push(new Set([fn]));69                }70            }71        }72        return this.#run(fn);73    }74    // return the queues for each path the function cares about75    // fn => {paths, dirs}76    #getQueues(fn) {77        const res = this.#reservations.get(fn);78        /* c8 ignore start */79        if (!res) {80            throw new Error('function does not have any path reservations');81        }82        /* c8 ignore stop */83        return {84            paths: res.paths.map((path) => this.#queues.get(path)),85            dirs: [...res.dirs].map(path => this.#queues.get(path)),86        };87    }88    // check if fn is first in line for all its paths, and is89    // included in the first set for all its dir queues90    check(fn) {91        const { paths, dirs } = this.#getQueues(fn);92        return (paths.every(q => q && q[0] === fn) &&93            dirs.every(q => q && q[0] instanceof Set && q[0].has(fn)));94    }95    // run the function if it's first in line and not already running96    #run(fn) {97        if (this.#running.has(fn) || !this.check(fn)) {98            return false;99        }100        this.#running.add(fn);101        fn(() => this.#clear(fn));102        return true;103    }104    #clear(fn) {105        if (!this.#running.has(fn)) {106            return false;107        }108        const res = this.#reservations.get(fn);109        /* c8 ignore start */110        if (!res) {111            throw new Error('invalid reservation');112        }113        /* c8 ignore stop */114        const { paths, dirs } = res;115        const next = new Set();116        for (const path of paths) {117            const q = this.#queues.get(path);118            /* c8 ignore start */119            if (!q || q?.[0] !== fn) {120                continue;121            }122            /* c8 ignore stop */123            const q0 = q[1];124            if (!q0) {125                this.#queues.delete(path);126                continue;127            }128            q.shift();129            if (typeof q0 === 'function') {130                next.add(q0);131            }132            else {133                for (const f of q0) {134                    next.add(f);135                }136            }137        }138        for (const dir of dirs) {139            const q = this.#queues.get(dir);140            const q0 = q?.[0];141            /* c8 ignore next - type safety only */142            if (!q || !(q0 instanceof Set))143                continue;144            if (q0.size === 1 && q.length === 1) {145                this.#queues.delete(dir);146                continue;147            }148            else if (q0.size === 1) {149                q.shift();150                // next one must be a function,151                // or else the Set would've been reused152                const n = q[0];153                if (typeof n === 'function') {154                    next.add(n);155                }156            }157            else {158                q0.delete(fn);159            }160        }161        this.#running.delete(fn);162        next.forEach(fn => this.#run(fn));163        return true;164    }165}166//# sourceMappingURL=path-reservations.js.map