[all-commits] [llvm/llvm-project] ceffd6: [Support][Windows] Fix incorrect GetFinalPathNameB...

[Aleksandr Platonov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: ceffd6993c350b57f43cec3b6371b159fc4a3149
      https://github.com/llvm/llvm-project/commit/ceffd6993c350b57f43cec3b6371b159fc4a3149
  Author: Aleksandr Platonov <platonov.aleksandr at huawei.com>
  Date:   2020-08-26 (Wed, 26 Aug 2020)

  Changed paths:
    M llvm/lib/Support/Windows/Path.inc

  Log Message:
  -----------
  [Support][Windows] Fix incorrect GetFinalPathNameByHandleW() return value check in realPathFromHandle()

`GetFinalPathNameByHandleW(,,N,)` returns:
- `< N` on success (this value does not include the size of the terminating null character)
- `>= N` if buffer is too small (this value includes the size of the terminating null character)

So, when `N == Buffer.capacity() - 1`, we need to resize buffer if return value is > `Buffer.capacity() - 2`.
Also, we can set `N` to `Buffer.capacity()`.

Thus, without this patch `realPathFromHandle()` returns unfilled buffer when length of the final path of the file is equal to `Buffer.capacity()` or `Buffer.capacity() - 1`.

Reviewed By: andrewng, amccarth

Differential Revision: https://reviews.llvm.org/D86564