1 files changed, 94 insertions, 0 deletions
diff --git a/deps/npm/node_modules/read-package-tree/realpath.js b/deps/npm/node_modules/read-package-tree/realpath.js
new file mode 100644
index 0000000000..70c666064e
--- /dev/null
+++ b/deps/npm/node_modules/read-package-tree/realpath.js
@@ -0,0 +1,94 @@
+// look up the realpath, but cache stats to minimize overhead
+// If the parent folder is in  the realpath cache, then we just
+// lstat the child, since there's no need to do a full realpath
+// This is not a separate module, and is much simpler than Node's
+// built-in fs.realpath, because we only care about symbolic links,
+// so we can handle many fewer edge cases.
+
+const fs = require('fs')
+/* istanbul ignore next */
+const promisify = require('util').promisify || require('util-promisify')
+const readlink = promisify(fs.readlink)
+const lstat = promisify(fs.lstat)
+const { resolve, basename, dirname } = require('path')
+
+const realpathCached = (path, rpcache, stcache, depth) => {
+  // just a safety against extremely deep eloops
+  /* istanbul ignore next */
+  if (depth > 2000)
+    throw eloop(path)
+
+  path = resolve(path)
+  if (rpcache.has(path))
+    return Promise.resolve(rpcache.get(path))
+
+  const dir = dirname(path)
+  const base = basename(path)
+
+  if (base && rpcache.has(dir))
+    return realpathChild(dir, base, rpcache, stcache, depth)
+
+  // if it's the root, then we know it's real
+  if (!base) {
+    rpcache.set(dir, dir)
+    return Promise.resolve(dir)
+  }
+
+  // the parent, what is that?
+  // find out, and then come back.
+  return realpathCached(dir, rpcache, stcache, depth + 1).then(() =>
+    realpathCached(path, rpcache, stcache, depth + 1))
+}
+
+const lstatCached = (path, stcache) => {
+  if (stcache.has(path))
+    return Promise.resolve(stcache.get(path))
+
+  const p = lstat(path).then(st => {
+    stcache.set(path, st)
+    return st
+  })
+  stcache.set(path, p)
+  return p
+}
+
+// This is a slight fib, as it doesn't actually occur during a stat syscall.
+// But file systems are giant piles of lies, so whatever.
+const eloop = path =>
+  Object.assign(new Error(
+    `ELOOP: too many symbolic links encountered, stat '${path}'`), {
+    errno: -62,
+    syscall: 'stat',
+    code: 'ELOOP',
+    path: path,
+  })
+
+const realpathChild = (dir, base, rpcache, stcache, depth) => {
+  const realdir = rpcache.get(dir)
+  // that unpossible
+  /* istanbul ignore next */
+  if (typeof realdir === 'undefined')
+    throw new Error('in realpathChild without parent being in realpath cache')
+
+  const realish = resolve(realdir, base)
+  return lstatCached(realish, stcache).then(st => {
+    if (!st.isSymbolicLink()) {
+      rpcache.set(resolve(dir, base), realish)
+      return realish
+    }
+
+    let res
+    return readlink(realish).then(target => {
+      const resolved = res = resolve(realdir, target)
+      if (realish === resolved)
+        throw eloop(realish)
+
+      return realpathCached(resolved, rpcache, stcache, depth + 1)
+    }).then(real => {
+      rpcache.set(resolve(dir, base), real)
+      return real
+    })
+  })
+}
+
+module.exports = realpathCached