This is an archive of the discontinued Mercurial Phabricator instance.

Differential D4801

storageutil: extract filelog.cmp() to a standalone function
ClosedPublic

Authored by indygreg on Sep 28 2018, 8:18 PM.

Details

Reviewers
None
Group Reviewers
hg-reviewers
Commits
rHG422beffd71ba: storageutil: extract filelog.cmp() to a standalone function
Summary

As part of implementing an alternate storage backend, I found myself
reimplementing this code.

With a little massaging, we can extract filelog.cmp() to a standalone
function.

As part of this, the call to revlog.cmp() was inlined (it is just a
2-line function).

I also tweaked some variable names to improve readability. I'll
further tweak names in a subsequent commit.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

indygreg created this revision.Sep 28 2018, 8:18 PM
Closed by commit rHG422beffd71ba: storageutil: extract filelog.cmp() to a standalone function (authored by indygreg). · Explain WhyOct 3 2018, 11:05 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/filelog.py (21 lines)
Mmercurial/utils/storageutil.py (26 lines)

Diff 11615

mercurial/filelog.py

# XXX if self.read(node).startswith("\1\n"), this returns (size+4) # XXX if self.read(node).startswith("\1\n"), this returns (size+4)
return self._revlog.size(rev) return self._revlog.size(rev)
def cmp(self, node, text): def cmp(self, node, text):
"""compare text with a given file revision """compare text with a given file revision
returns True if text is different than what is stored. returns True if text is different than what is stored.
""" """
return storageutil.filerevisiondifferent(self, node, text)
t = text
if text.startswith('\1\n'):
t = '\1\n\1\n' + text
samehashes = not self._revlog.cmp(node, t)
if samehashes:
return False
# censored files compare against the empty file
if self.iscensored(self.rev(node)):
return text != ''
# renaming a file produces a different hash, even if the data
# remains unchanged. Check if it's the case (slow):
if self.renamed(node):
t2 = self.read(node)
return t2 != text
return True
def verifyintegrity(self, state): def verifyintegrity(self, state):
return self._revlog.verifyintegrity(state) return self._revlog.verifyintegrity(state)
def storageinfo(self, exclusivefiles=False, sharedfiles=False, def storageinfo(self, exclusivefiles=False, sharedfiles=False,
revisionscount=False, trackedsize=False, revisionscount=False, trackedsize=False,
storedsize=False): storedsize=False):
return self._revlog.storageinfo( return self._revlog.storageinfo(

mercurial/utils/storageutil.py

# copy and copyrev occur in pairs. In rare cases due to old bugs, # copy and copyrev occur in pairs. In rare cases due to old bugs,
# one can occur without the other. So ensure both are present to flag # one can occur without the other. So ensure both are present to flag
# as a copy. # as a copy.
if meta and b'copy' in meta and b'copyrev' in meta: if meta and b'copy' in meta and b'copyrev' in meta:
return meta[b'copy'], bin(meta[b'copyrev']) return meta[b'copy'], bin(meta[b'copyrev'])
return False return False
def filerevisiondifferent(store, node, filedata):
"""Determines whether file data is equivalent to a stored node."""
if filedata.startswith(b'\x01\n'):
revisiontext = b'\x01\n\x01\n' + filedata
else:
revisiontext = filedata
p1, p2 = store.parents(node)
computednode = hashrevisionsha1(revisiontext, p1, p2)
if computednode == node:
return False
# Censored files compare against the empty file.
if store.iscensored(store.rev(node)):
return filedata != b''
# Renaming a file produces a different hash, even if the data
# remains unchanged. Check if that's the case.
if store.renamed(node):
return store.read(node) != filedata
return True
def iterrevs(storelen, start=0, stop=None): def iterrevs(storelen, start=0, stop=None):
"""Iterate over revision numbers in a store.""" """Iterate over revision numbers in a store."""
step = 1 step = 1
if stop is not None: if stop is not None:
if start > stop: if start > stop:
step = -1 step = -1
stop += step stop += step