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Differential D5118

storageutil: extract most of peek_censored from revlog
ClosedPublic

Authored by indygreg on Oct 16 2018, 11:55 AM.

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rHGb0fbd1792e2d: storageutil: extract most of peek_censored from revlog
Summary

This function is super hacky and isn't correct 100% of the time. I'm going
to need this functionality on a future non-revlog store.

Let's copy things to storageutil so this code only exists once.

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.Oct 16 2018, 11:55 AM
Closed by commit rHGb0fbd1792e2d: storageutil: extract most of peek_censored from revlog (authored by indygreg). · Explain WhyOct 17 2018, 9:22 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/revlog.py (18 lines)
Mmercurial/utils/storageutil.py (29 lines)

Diff 12199

mercurial/revlog.py

return self.flags(rev) & REVIDX_ISCENSORED return self.flags(rev) & REVIDX_ISCENSORED
def _peek_iscensored(self, baserev, delta, flush): def _peek_iscensored(self, baserev, delta, flush):
"""Quickly check if a delta produces a censored revision.""" """Quickly check if a delta produces a censored revision."""
if not self._censorable: if not self._censorable:
return False return False
# Fragile heuristic: unless new file meta keys are added alphabetically return storageutil.deltaiscensored(delta, baserev, self.rawsize)
# preceding "censored", all censored revisions are prefixed by
# "\1\ncensored:". A delta producing such a censored revision must be a
# full-replacement delta, so we inspect the first and only patch in the
# delta for this prefix.
hlen = struct.calcsize(">lll")
if len(delta) <= hlen:
return False
oldlen = self.rawsize(baserev)
newlen = len(delta) - hlen
if delta[:hlen] != mdiff.replacediffheader(oldlen, newlen):
return False
add = "\1\ncensored:"
addlen = len(add)
return newlen >= addlen and delta[hlen:hlen + addlen] == add
def getstrippoint(self, minlink): def getstrippoint(self, minlink):
"""find the minimum rev that must be stripped to strip the linkrev """find the minimum rev that must be stripped to strip the linkrev
Returns a tuple containing the minimum rev and a set of all revs that Returns a tuple containing the minimum rev and a set of all revs that
have linkrevs that will be broken by this strip. have linkrevs that will be broken by this strip.
""" """
return storageutil.resolvestripinfo(minlink, len(self) - 1, return storageutil.resolvestripinfo(minlink, len(self) - 1,

mercurial/utils/storageutil.py

# storageutil.py - Storage functionality agnostic of backend implementation. # storageutil.py - Storage functionality agnostic of backend implementation.
# #
# Copyright 2018 Gregory Szorc <gregory.szorc@gmail.com> # Copyright 2018 Gregory Szorc <gregory.szorc@gmail.com>
# #
# This software may be used and distributed according to the terms of the # This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version. # GNU General Public License version 2 or any later version.
from __future__ import absolute_import from __future__ import absolute_import
import hashlib import hashlib
import re import re
import struct
from ..i18n import _ from ..i18n import _
from ..node import ( from ..node import (
bin, bin,
nullid, nullid,
nullrev, nullrev,
) )
from .. import ( from .. import (
p2node=fnode(p2rev), p2node=fnode(p2rev),
basenode=fnode(baserev), basenode=fnode(baserev),
flags=flagsfn(rev) if flagsfn else 0, flags=flagsfn(rev) if flagsfn else 0,
baserevisionsize=baserevisionsize, baserevisionsize=baserevisionsize,
revision=revision, revision=revision,
delta=delta) delta=delta)
prevrev = rev prevrev = rev
def deltaiscensored(delta, baserev, baselenfn):
"""Determine if a delta represents censored revision data.
``baserev`` is the base revision this delta is encoded against.
``baselenfn`` is a callable receiving a revision number that resolves the
length of the revision fulltext.
Returns a bool indicating if the result of the delta represents a censored
revision.
"""
# Fragile heuristic: unless new file meta keys are added alphabetically
# preceding "censored", all censored revisions are prefixed by
# "\1\ncensored:". A delta producing such a censored revision must be a
# full-replacement delta, so we inspect the first and only patch in the
# delta for this prefix.
hlen = struct.calcsize(">lll")
if len(delta) <= hlen:
return False
oldlen = baselenfn(baserev)
newlen = len(delta) - hlen
if delta[:hlen] != mdiff.replacediffheader(oldlen, newlen):
return False
add = "\1\ncensored:"
addlen = len(add)
return newlen >= addlen and delta[hlen:hlen + addlen] == add