view tests/test-revert-flags.t @ 14927:2aa3e07b2f07

posix, windows: introduce cachestat

This class contains a stat result, and possibly other file info to reliably
determine between two points in time whether a file has changed.

Uniquely identifying a file gives us that reliability because we either
atomic rename or append. So one of two will happen: the file 'id' will change,
or the size of the file will change.

posix implements it simply by calling os.stat() and checking if the result
has st_ino.

For now on Windows we always assume the path is uncacheable. This can be
improved on NTFS due to file IDs: http://msdn.microsoft.com/en-us/library/aa363788(v=vs.85).aspx

So we need to find out if a file path is on an NTFS drive, for that we have:

- GetVolumeInformation, which unfortunately only works with a root path (but is available on XP)
- GetVolumeInformationByHandleW, works on a full file path but requires Vista or higher

  $ "$TESTDIR/hghave" execbit || exit 80

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ chmod 644 foo
  $ hg ci -qAm '644'

  $ chmod 755 foo
  $ hg ci -qAm '755'

reverting to rev 0

  $ hg revert -a -r 0
  reverting foo
  $ hg st
  M foo
  $ hg diff --git
  diff --git a/foo b/foo
  old mode 100755
  new mode 100644