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// check to see if a bin is allowed to be overwritten
// either rejects or resolves to nothing. return value not relevant.
const isWindows = require('./is-windows.js')
const binTarget = require('./bin-target.js')
const { resolve, dirname } = require('path')
const readCmdShim = require('read-cmd-shim')
const fs = require('fs')
const { promisify } = require('util')
const readlink = promisify(fs.readlink)
const checkBin = async ({ bin, path, top, global, force }) => {
// always ok to clobber when forced
// always ok to clobber local bins, or when forced
if (force || !global || !top) {
return
}
// ok, need to make sure, then
const target = resolve(binTarget({ path, top }), bin)
path = resolve(path)
return isWindows ? checkShim({ target, path }) : checkLink({ target, path })
}
// only enoent is allowed. anything else is a problem.
const handleReadLinkError = async ({ er, target }) =>
er.code === 'ENOENT' ? null
: failEEXIST({ target })
const checkLink = async ({ target, path }) => {
const current = await readlink(target)
.catch(er => handleReadLinkError({ er, target }))
if (!current) {
return
}
const resolved = resolve(dirname(target), current)
if (resolved.toLowerCase().indexOf(path.toLowerCase()) !== 0) {
return failEEXIST({ target })
}
}
const handleReadCmdShimError = ({ er, target }) =>
er.code === 'ENOENT' ? null
: failEEXIST({ target })
const failEEXIST = ({ target }) =>
Promise.reject(Object.assign(new Error('EEXIST: file already exists'), {
path: target,
code: 'EEXIST',
}))
const checkShim = async ({ target, path }) => {
const shims = [
target,
target + '.cmd',
target + '.ps1',
]
await Promise.all(shims.map(async shim => {
const current = await readCmdShim(shim)
.catch(er => handleReadCmdShimError({ er, target: shim }))
if (!current) {
return
}
const resolved = resolve(dirname(shim), current.replace(/\\/g, '/'))
if (resolved.toLowerCase().indexOf(path.toLowerCase()) !== 0) {
return failEEXIST({ target: shim })
}
}))
}
module.exports = checkBin
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