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
Corrupt an hg repo with two pulls.
create one repo with a long history
$ hg init source1
$ cd source1
$ touch foo
$ hg add foo
$ for i in 1 2 3 4 5 6 7 8 9 10; do
> echo $i >> foo
> hg ci -m $i
> done
$ cd ..
create a third repo to pull both other repos into it
$ hg init version2
$ hg -R version2 pull source1 &
$ sleep 1
pulling from source1
requesting all changes
adding changesets
adding manifests
adding file changes
added 10 changesets with 10 changes to 1 files
(run 'hg update' to get a working copy)
$ hg clone --pull -U version2 corrupted
requesting all changes
adding changesets
adding manifests
adding file changes
added 10 changesets with 10 changes to 1 files
$ wait
$ hg -R corrupted verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 10 changesets, 10 total revisions
$ hg -R version2 verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 10 changesets, 10 total revisions