170 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
			
		
		
	
	
			170 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
"use strict";
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// A path exclusive reservation system
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// reserve([list, of, paths], fn)
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// When the fn is first in line for all its paths, it
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// is called with a cb that clears the reservation.
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//
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// Used by async unpack to avoid clobbering paths in use,
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// while still allowing maximal safe parallelization.
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.PathReservations = void 0;
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const node_path_1 = require("node:path");
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const normalize_unicode_js_1 = require("./normalize-unicode.js");
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const strip_trailing_slashes_js_1 = require("./strip-trailing-slashes.js");
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const platform = process.env.TESTING_TAR_FAKE_PLATFORM || process.platform;
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const isWindows = platform === 'win32';
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// return a set of parent dirs for a given path
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// '/a/b/c/d' -> ['/', '/a', '/a/b', '/a/b/c', '/a/b/c/d']
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const getDirs = (path) => {
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    const dirs = path
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        .split('/')
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        .slice(0, -1)
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        .reduce((set, path) => {
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        const s = set[set.length - 1];
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        if (s !== undefined) {
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            path = (0, node_path_1.join)(s, path);
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        }
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        set.push(path || '/');
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        return set;
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    }, []);
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    return dirs;
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};
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class PathReservations {
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    // path => [function or Set]
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    // A Set object means a directory reservation
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    // A fn is a direct reservation on that path
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    #queues = new Map();
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    // fn => {paths:[path,...], dirs:[path, ...]}
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    #reservations = new Map();
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    // functions currently running
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    #running = new Set();
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    reserve(paths, fn) {
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        paths =
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            isWindows ?
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                ['win32 parallelization disabled']
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                : paths.map(p => {
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                    // don't need normPath, because we skip this entirely for windows
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                    return (0, strip_trailing_slashes_js_1.stripTrailingSlashes)((0, node_path_1.join)((0, normalize_unicode_js_1.normalizeUnicode)(p))).toLowerCase();
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                });
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        const dirs = new Set(paths.map(path => getDirs(path)).reduce((a, b) => a.concat(b)));
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        this.#reservations.set(fn, { dirs, paths });
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        for (const p of paths) {
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            const q = this.#queues.get(p);
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            if (!q) {
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                this.#queues.set(p, [fn]);
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            }
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            else {
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                q.push(fn);
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            }
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        }
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        for (const dir of dirs) {
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            const q = this.#queues.get(dir);
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            if (!q) {
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                this.#queues.set(dir, [new Set([fn])]);
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            }
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            else {
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                const l = q[q.length - 1];
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                if (l instanceof Set) {
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                    l.add(fn);
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                }
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                else {
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                    q.push(new Set([fn]));
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                }
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            }
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        }
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        return this.#run(fn);
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    }
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    // return the queues for each path the function cares about
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    // fn => {paths, dirs}
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    #getQueues(fn) {
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        const res = this.#reservations.get(fn);
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        /* c8 ignore start */
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        if (!res) {
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            throw new Error('function does not have any path reservations');
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        }
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        /* c8 ignore stop */
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        return {
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            paths: res.paths.map((path) => this.#queues.get(path)),
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            dirs: [...res.dirs].map(path => this.#queues.get(path)),
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        };
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    }
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    // check if fn is first in line for all its paths, and is
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    // included in the first set for all its dir queues
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    check(fn) {
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        const { paths, dirs } = this.#getQueues(fn);
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        return (paths.every(q => q && q[0] === fn) &&
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            dirs.every(q => q && q[0] instanceof Set && q[0].has(fn)));
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    }
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    // run the function if it's first in line and not already running
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    #run(fn) {
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        if (this.#running.has(fn) || !this.check(fn)) {
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            return false;
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        }
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        this.#running.add(fn);
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        fn(() => this.#clear(fn));
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        return true;
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    }
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    #clear(fn) {
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        if (!this.#running.has(fn)) {
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            return false;
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        }
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        const res = this.#reservations.get(fn);
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        /* c8 ignore start */
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        if (!res) {
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            throw new Error('invalid reservation');
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        }
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        /* c8 ignore stop */
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        const { paths, dirs } = res;
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        const next = new Set();
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        for (const path of paths) {
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            const q = this.#queues.get(path);
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            /* c8 ignore start */
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            if (!q || q?.[0] !== fn) {
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                continue;
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            }
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            /* c8 ignore stop */
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            const q0 = q[1];
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            if (!q0) {
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                this.#queues.delete(path);
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                continue;
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            }
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            q.shift();
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            if (typeof q0 === 'function') {
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                next.add(q0);
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            }
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            else {
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                for (const f of q0) {
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                    next.add(f);
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                }
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            }
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        }
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        for (const dir of dirs) {
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            const q = this.#queues.get(dir);
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            const q0 = q?.[0];
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            /* c8 ignore next - type safety only */
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            if (!q || !(q0 instanceof Set))
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                continue;
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            if (q0.size === 1 && q.length === 1) {
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                this.#queues.delete(dir);
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                continue;
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            }
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            else if (q0.size === 1) {
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                q.shift();
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                // next one must be a function,
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                // or else the Set would've been reused
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                const n = q[0];
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                if (typeof n === 'function') {
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                    next.add(n);
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                }
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            }
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            else {
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                q0.delete(fn);
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            }
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        }
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        this.#running.delete(fn);
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        next.forEach(fn => this.#run(fn));
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        return true;
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    }
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}
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exports.PathReservations = PathReservations;
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//# sourceMappingURL=path-reservations.js.map
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