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
$ hg init
Revision 0:
$ echo "unchanged" > unchanged
$ echo "remove me" > remove
$ echo "copy me" > copy
$ echo "move me" > move
$ for i in 1 2 3 4 5 6 7 8 9; do
> echo "merge ok $i" >> zzz1_merge_ok
> done
$ echo "merge bad" > zzz2_merge_bad
$ hg ci -Am "revision 0"
adding copy
adding move
adding remove
adding unchanged
adding zzz1_merge_ok
adding zzz2_merge_bad
Revision 1:
$ hg rm remove
$ hg mv move moved
$ hg cp copy copied
$ echo "added" > added
$ hg add added
$ echo "new first line" > zzz1_merge_ok
$ hg cat zzz1_merge_ok >> zzz1_merge_ok
$ echo "new last line" >> zzz2_merge_bad
$ hg ci -m "revision 1"
Local changes to revision 0:
$ hg co 0
4 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ echo "new last line" >> zzz1_merge_ok
$ echo "another last line" >> zzz2_merge_bad
$ hg diff --nodates | grep "^[+-][^<>]"
--- a/zzz1_merge_ok
+++ b/zzz1_merge_ok
+new last line
--- a/zzz2_merge_bad
+++ b/zzz2_merge_bad
+another last line
$ hg st
M zzz1_merge_ok
M zzz2_merge_bad
Local merge with bad merge tool:
$ HGMERGE=false hg co
merging zzz1_merge_ok
merging zzz2_merge_bad
merging zzz2_merge_bad failed!
3 files updated, 1 files merged, 2 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
[1]
$ hg co 0
merging zzz1_merge_ok
merging zzz2_merge_bad
warning: conflicts during merge.
merging zzz2_merge_bad failed!
2 files updated, 1 files merged, 3 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
[1]
$ hg diff --nodates | grep "^[+-][^<>]"
--- a/zzz1_merge_ok
+++ b/zzz1_merge_ok
+new last line
--- a/zzz2_merge_bad
+++ b/zzz2_merge_bad
+another last line
+=======
$ hg st
M zzz1_merge_ok
M zzz2_merge_bad
? zzz2_merge_bad.orig
Local merge with conflicts:
$ hg co
merging zzz1_merge_ok
merging zzz2_merge_bad
warning: conflicts during merge.
merging zzz2_merge_bad failed!
3 files updated, 1 files merged, 2 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
[1]
$ hg co 0
merging zzz1_merge_ok
merging zzz2_merge_bad
warning: conflicts during merge.
merging zzz2_merge_bad failed!
2 files updated, 1 files merged, 3 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
[1]
$ hg diff --nodates | grep "^[+-][^<>]"
--- a/zzz1_merge_ok
+++ b/zzz1_merge_ok
+new last line
--- a/zzz2_merge_bad
+++ b/zzz2_merge_bad
+another last line
+=======
+=======
+new last line
+=======
$ hg st
M zzz1_merge_ok
M zzz2_merge_bad
? zzz2_merge_bad.orig
Local merge without conflicts:
$ hg revert zzz2_merge_bad
$ hg co
merging zzz1_merge_ok
4 files updated, 1 files merged, 2 files removed, 0 files unresolved
$ hg diff --nodates | grep "^[+-][^<>]"
--- a/zzz1_merge_ok
+++ b/zzz1_merge_ok
+new last line
$ hg st
M zzz1_merge_ok
? zzz2_merge_bad.orig