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2 years ago
'use strict'
const fs = require('fs')
const util = require('util')
const chmod = util.promisify(fs.chmod)
const unlink = util.promisify(fs.unlink)
const stat = util.promisify(fs.stat)
const move = require('@npmcli/move-file')
const pinflight = require('promise-inflight')
module.exports = moveFile
function moveFile (src, dest) {
const isWindows = global.__CACACHE_TEST_FAKE_WINDOWS__ ||
process.platform === 'win32'
// This isn't quite an fs.rename -- the assumption is that
// if `dest` already exists, and we get certain errors while
// trying to move it, we should just not bother.
//
// In the case of cache corruption, users will receive an
// EINTEGRITY error elsewhere, and can remove the offending
// content their own way.
//
// Note that, as the name suggests, this strictly only supports file moves.
return new Promise((resolve, reject) => {
fs.link(src, dest, (err) => {
if (err) {
if (isWindows && err.code === 'EPERM') {
// XXX This is a really weird way to handle this situation, as it
// results in the src file being deleted even though the dest
// might not exist. Since we pretty much always write files to
// deterministic locations based on content hash, this is likely
// ok (or at worst, just ends in a future cache miss). But it would
// be worth investigating at some time in the future if this is
// really what we want to do here.
return resolve()
} else if (err.code === 'EEXIST' || err.code === 'EBUSY') {
// file already exists, so whatever
return resolve()
} else
return reject(err)
} else
return resolve()
})
})
.then(() => {
// content should never change for any reason, so make it read-only
return Promise.all([
unlink(src),
!isWindows && chmod(dest, '0444'),
])
})
.catch(() => {
return pinflight('cacache-move-file:' + dest, () => {
return stat(dest).catch((err) => {
if (err.code !== 'ENOENT') {
// Something else is wrong here. Bail bail bail
throw err
}
// file doesn't already exist! let's try a rename -> copy fallback
// only delete if it successfully copies
return move(src, dest)
})
})
})
}