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2e54524955
PR-URL: https://github.com/nodejs/node/pull/35474 Reviewed-By: Ruy Adorno <ruyadorno@github.com> Reviewed-By: Ujjwal Sharma <ryzokuken@disroot.org> Reviewed-By: Ben Coe <bencoe@gmail.com> Reviewed-By: Geoffrey Booth <webmaster@geoffreybooth.com> Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Shelley Vohr <codebytere@gmail.com> Reviewed-By: Guy Bedford <guybedford@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
93 lines
2.6 KiB
JavaScript
93 lines
2.6 KiB
JavaScript
// look up the realpath, but cache stats to minimize overhead
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// If the parent folder is in the realpath cache, then we just
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// lstat the child, since there's no need to do a full realpath
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// This is not a separate module, and is much simpler than Node's
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// built-in fs.realpath, because we only care about symbolic links,
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// so we can handle many fewer edge cases.
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const fs = require('fs')
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const promisify = require('util').promisify
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const readlink = promisify(fs.readlink)
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const lstat = promisify(fs.lstat)
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const { resolve, basename, dirname } = require('path')
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const realpathCached = (path, rpcache, stcache, depth) => {
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// just a safety against extremely deep eloops
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/* istanbul ignore next */
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if (depth > 2000)
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throw eloop(path)
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path = resolve(path)
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if (rpcache.has(path))
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return Promise.resolve(rpcache.get(path))
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const dir = dirname(path)
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const base = basename(path)
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if (base && rpcache.has(dir))
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return realpathChild(dir, base, rpcache, stcache, depth)
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// if it's the root, then we know it's real
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if (!base) {
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rpcache.set(dir, dir)
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return Promise.resolve(dir)
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}
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// the parent, what is that?
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// find out, and then come back.
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return realpathCached(dir, rpcache, stcache, depth + 1).then(() =>
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realpathCached(path, rpcache, stcache, depth + 1))
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}
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const lstatCached = (path, stcache) => {
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if (stcache.has(path))
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return Promise.resolve(stcache.get(path))
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const p = lstat(path).then(st => {
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stcache.set(path, st)
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return st
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})
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stcache.set(path, p)
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return p
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}
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// This is a slight fib, as it doesn't actually occur during a stat syscall.
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// But file systems are giant piles of lies, so whatever.
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const eloop = path =>
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Object.assign(new Error(
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`ELOOP: too many symbolic links encountered, stat '${path}'`), {
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errno: -62,
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syscall: 'stat',
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code: 'ELOOP',
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path: path,
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})
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const realpathChild = (dir, base, rpcache, stcache, depth) => {
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const realdir = rpcache.get(dir)
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// that unpossible
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/* istanbul ignore next */
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if (typeof realdir === 'undefined')
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throw new Error('in realpathChild without parent being in realpath cache')
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const realish = resolve(realdir, base)
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return lstatCached(realish, stcache).then(st => {
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if (!st.isSymbolicLink()) {
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rpcache.set(resolve(dir, base), realish)
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return realish
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}
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return readlink(realish).then(target => {
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const resolved = resolve(realdir, target)
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if (realish === resolved)
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throw eloop(realish)
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return realpathCached(resolved, rpcache, stcache, depth + 1)
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}).then(real => {
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rpcache.set(resolve(dir, base), real)
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return real
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})
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})
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}
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module.exports = realpathCached
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