72 lines
1.7 KiB
JavaScript
72 lines
1.7 KiB
JavaScript
const cache = new Map()
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const fs = require('fs')
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const { dirname, resolve } = require('path')
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const lstat = path => new Promise((res, rej) =>
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fs.lstat(path, (er, st) => er ? rej(er) : res(st)))
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const inferOwner = path => {
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path = resolve(path)
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if (cache.has(path))
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return Promise.resolve(cache.get(path))
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const statThen = st => {
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const { uid, gid } = st
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cache.set(path, { uid, gid })
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return { uid, gid }
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}
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const parent = dirname(path)
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const parentTrap = parent === path ? null : er => {
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return inferOwner(parent).then((owner) => {
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cache.set(path, owner)
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return owner
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})
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}
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return lstat(path).then(statThen, parentTrap)
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}
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const inferOwnerSync = path => {
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path = resolve(path)
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if (cache.has(path))
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return cache.get(path)
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const parent = dirname(path)
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// avoid obscuring call site by re-throwing
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// "catch" the error by returning from a finally,
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// only if we're not at the root, and the parent call works.
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let threw = true
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try {
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const st = fs.lstatSync(path)
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threw = false
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const { uid, gid } = st
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cache.set(path, { uid, gid })
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return { uid, gid }
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} finally {
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if (threw && parent !== path) {
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const owner = inferOwnerSync(parent)
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cache.set(path, owner)
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return owner // eslint-disable-line no-unsafe-finally
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}
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}
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}
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const inflight = new Map()
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module.exports = path => {
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path = resolve(path)
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if (inflight.has(path))
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return Promise.resolve(inflight.get(path))
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const p = inferOwner(path).then(owner => {
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inflight.delete(path)
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return owner
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})
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inflight.set(path, p)
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return p
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}
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module.exports.sync = inferOwnerSync
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module.exports.clearCache = () => {
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cache.clear()
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inflight.clear()
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}
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