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Differential D4646

revlog: store flag processors per revlog
ClosedPublic

Authored by indygreg on Sep 18 2018, 6:40 PM.

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Group Reviewers
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Commits
rHG7b2b42fc377a: revlog: store flag processors per revlog
Summary

Previously, revlog flag processing would consult a global dict
when processing flags. This was simple. But it had the undesired
side-effect that any extension could load flag processors once
and those flag processors would be available to any revlog that was
subsequent loaded in the process. e.g. in hgweb, if the narrow
extension were loaded for repo A but not repo B, repo B would be
able to decode ellipsis flags even though it shouldn't be able to.

Making the flag processors dict per-revlog allows us to have per-revlog
controls over what flag processors are available, thus preserving
desired granular access to flag processors depending on the revlog's
needs.

If a flag processor is globally registered, it is still globally
available. So this commit should not meaningfully change behavior.

Diff Detail

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

indygreg created this revision.Sep 18 2018, 6:40 PM
Closed by commit rHG7b2b42fc377a: revlog: store flag processors per revlog (authored by indygreg). · Explain WhySep 23 2018, 5:39 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/revlog.py (8 lines)

Diff 11272

mercurial/revlog.py

self._nodepos = None self._nodepos = None
self._compengine = 'zlib' self._compengine = 'zlib'
self._maxdeltachainspan = -1 self._maxdeltachainspan = -1
self._withsparseread = False self._withsparseread = False
self._sparserevlog = False self._sparserevlog = False
self._srdensitythreshold = 0.50 self._srdensitythreshold = 0.50
self._srmingapsize = 262144 self._srmingapsize = 262144
# Make copy of flag processors so each revlog instance can support
# custom flags.
self._flagprocessors = dict(_flagprocessors)
mmapindexthreshold = None mmapindexthreshold = None
v = REVLOG_DEFAULT_VERSION v = REVLOG_DEFAULT_VERSION
opts = getattr(opener, 'options', None) opts = getattr(opener, 'options', None)
if opts is not None: if opts is not None:
if 'revlogv2' in opts: if 'revlogv2' in opts:
# version 2 revlogs always use generaldelta. # version 2 revlogs always use generaldelta.
v = REVLOGV2 | FLAG_GENERALDELTA | FLAG_INLINE_DATA v = REVLOGV2 | FLAG_GENERALDELTA | FLAG_INLINE_DATA
elif 'revlogv1' in opts: elif 'revlogv1' in opts:
orderedflags = reversed(orderedflags) orderedflags = reversed(orderedflags)
for flag in orderedflags: for flag in orderedflags:
# If a flagprocessor has been registered for a known flag, apply the # If a flagprocessor has been registered for a known flag, apply the
# related operation transform and update result tuple. # related operation transform and update result tuple.
if flag & flags: if flag & flags:
vhash = True vhash = True
if flag not in _flagprocessors: if flag not in self._flagprocessors:
message = _("missing processor for flag '%#x'") % (flag) message = _("missing processor for flag '%#x'") % (flag)
raise RevlogError(message) raise RevlogError(message)
processor = _flagprocessors[flag] processor = self._flagprocessors[flag]
if processor is not None: if processor is not None:
readtransform, writetransform, rawtransform = processor readtransform, writetransform, rawtransform = processor
if raw: if raw:
vhash = rawtransform(self, text) vhash = rawtransform(self, text)
elif operation == 'read': elif operation == 'read':
text, vhash = readtransform(self, text) text, vhash = readtransform(self, text)
else: # write operation else: # write operation