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ticket #2882: preserve user mtime

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This commit is contained in:
meejah 2018-01-08 16:12:36 -07:00
parent 5c4312711f
commit 1171bf13af
2 changed files with 32 additions and 11 deletions
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2
docs/proposed/magic-folder/remote-to-local-sync.rst
View File

@ -371,7 +371,7 @@ this procedure for an overwrite in response to a remote change:
to obtain an initial classification as an overwrite or a
conflict. (This takes as input the ``last_downloaded_uri``
field from the directory entry of the changed ``foo``.)
3. Set the ``mtime`` of the replacement file to be *T* seconds
3. Set the ``mtime`` of the replacement file to be at least *T* seconds
before the current local time. Stat the replacement file
to obtain its ``mtime`` and ``ctime`` as stored in the local
filesystem, and update the file's last-seen statinfo in

41
src/allmydata/frontends/magic_folder.py
View File

@ -703,10 +703,13 @@ class Uploader(QueueMixin):
self._count('objects_not_uploaded')
return False
# look out! there's another place we set a "metadata"
# object like this (for new, not deleted files)
metadata = {
'version': new_version,
'deleted': True,
'last_downloaded_timestamp': last_downloaded_timestamp,
'user_mtime': pathinfo.ctime_ns / 1000000000.0, # why are we using ns in PathInfo??
}
if db_entry.last_downloaded_uri is not None:
metadata['last_downloaded_uri'] = db_entry.last_downloaded_uri
@ -782,6 +785,7 @@ class Uploader(QueueMixin):
metadata = {
'version': new_version,
'last_downloaded_timestamp': last_downloaded_timestamp,
'user_mtime': pathinfo.mtime_ns / 1000000000.0, # why are we using ns in PathInfo??
}
if db_entry is not None and db_entry.last_downloaded_uri is not None:
metadata['last_downloaded_uri'] = db_entry.last_downloaded_uri
@ -849,14 +853,23 @@ class WriteFileMixin(object):
def _get_conflicted_filename(self, abspath_u):
return abspath_u + u".conflict"
def _write_downloaded_file(self, local_path_u, abspath_u, file_contents, is_conflict=False, now=None):
self._log("_write_downloaded_file(%r, <%d bytes>, is_conflict=%r, now=%r)"
% (abspath_u, len(file_contents), is_conflict, now))
def _write_downloaded_file(self, local_path_u, abspath_u, file_contents,
is_conflict=False, now=None, mtime=None):
self._log(
("_write_downloaded_file({abspath}, <{file_size} bytes>,"
" is_conflict={is_conflict}, now={now}, mtime={mtime})").format(
abspath=abspath_u,
file_size=len(file_contents),
is_conflict=is_conflict,
now=now,
mtime=mtime,
)
)
# 1. Write a temporary file, say .foo.tmp.
# 2. is_conflict determines whether this is an overwrite or a conflict.
# 3. Set the mtime of the replacement file to be T seconds before the
# current local time.
# current local time, or mtime whichever is oldest
# 4. Perform a file replacement with backup filename foo.backup,
# replaced file foo, and replacement file .foo.tmp. If any step of
# this operation fails, reclassify as a conflict and stop.
@ -874,11 +887,14 @@ class WriteFileMixin(object):
fileutil.write(replacement_path_u, file_contents)
os.chmod(replacement_path_u, (~ self._umask) & 0666)
# FUDGE_SECONDS is used to determine if another process
# has written to the same file concurrently. This is described
# in the Earth Dragon section of our design document:
# FUDGE_SECONDS is used to determine if another process has
# written to the same file concurrently. This is described in
# the Earth Dragon section of our design document ("T" is the
# spec is FUDGE_SECONDS here):
# docs/proposed/magic-folder/remote-to-local-sync.rst
os.utime(replacement_path_u, (now, now - self.FUDGE_SECONDS))
fudge_time = now - self.FUDGE_SECONDS
modified_time = min(fudge_time, mtime) if mtime else fudge_time
os.utime(replacement_path_u, (now, modified_time))
if is_conflict:
return self._rename_conflicted_file(abspath_u, replacement_path_u)
else:
@ -1224,8 +1240,13 @@ class Downloader(QueueMixin, WriteFileMixin):
d.addCallback(lambda ign: self._rename_deleted_file(abspath_u))
else:
d.addCallback(lambda ign: item.file_node.download_best_version(progress=item.progress))
d.addCallback(lambda contents: self._write_downloaded_file(self._local_path_u, abspath_u, contents,
is_conflict=is_conflict))
d.addCallback(
lambda contents: self._write_downloaded_file(
self._local_path_u, abspath_u, contents,
is_conflict=is_conflict,
mtime=item.metadata.get('user_mtime', item.metadata.get('tahoe', {}).get('linkmotime')),
)
)
d.addCallbacks(do_update_db)
d.addErrback(failed)