update

package/node_modules/bin-links/lib/check-bin.js

@@ -0,0 +1,74 @@
+// 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 { readlink } = require('fs/promises')
+
+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