Mercurial > hg
view mercurial/filelog.py @ 40056:324b4b10351e
revlog: rewrite censoring logic
I was able to corrupt a revlog relatively easily with the existing
censoring code. The underlying problem is that the existing code
doesn't fully take delta chains into account. When copying revisions
that occur after the censored revision, the delta base can refer
to a censored revision. Then at read time, things blow up due to the
revision data not being a compressed delta.
This commit rewrites the revlog censoring code to take a higher-level
approach. We now create a new revlog instance pointing at temp files.
We iterate through each revision in the source revlog and insert
those revisions into the new revlog, replacing the censored revision's
data along the way.
The new implementation isn't as efficient as the old one. This is
because it will fully engage delta computation on insertion. But I
don't think it matters.
The new implementation is a bit hacky because it attempts to reload
the revlog instance with a new revlog index/data file. This is fragile.
But this is needed because the index (which could be backed by C) would
have a cached copy of the old, possibly changed data and that could
lead to problems accessing index or revision data later.
One benefit of the new approach is that we integrate with the
transaction. The old revlog is backed up and if the transaction is
rolled back, the original revlog is restored.
As part of this, we had to teach the transaction about the store
vfs. I'm not super keen about this. But this was the easiest way
to hook things up to the transaction. We /could/ just ignore the
transaction like we were doing before. But any file mutation should
be governed by transaction semantics, including undo during rollback.
Differential Revision: https://phab.mercurial-scm.org/D4869
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 02 Oct 2018 17:34:34 -0700 |
parents | 1470183068b8 |
children | f1a39128da95 |
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# filelog.py - file history class for mercurial # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import from . import ( error, repository, revlog, ) from .utils import ( interfaceutil, storageutil, ) @interfaceutil.implementer(repository.ifilestorage) class filelog(object): def __init__(self, opener, path): self._revlog = revlog.revlog(opener, '/'.join(('data', path + '.i')), censorable=True) # Full name of the user visible file, relative to the repository root. # Used by LFS. self._revlog.filename = path def __len__(self): return len(self._revlog) def __iter__(self): return self._revlog.__iter__() def revs(self, start=0, stop=None): return self._revlog.revs(start=start, stop=stop) def parents(self, node): return self._revlog.parents(node) def parentrevs(self, rev): return self._revlog.parentrevs(rev) def rev(self, node): return self._revlog.rev(node) def node(self, rev): return self._revlog.node(rev) def lookup(self, node): return storageutil.fileidlookup(self._revlog, node, self._revlog.indexfile) def linkrev(self, rev): return self._revlog.linkrev(rev) def commonancestorsheads(self, node1, node2): return self._revlog.commonancestorsheads(node1, node2) # Used by dagop.blockdescendants(). def descendants(self, revs): return self._revlog.descendants(revs) def heads(self, start=None, stop=None): return self._revlog.heads(start, stop) # Used by hgweb, children extension. def children(self, node): return self._revlog.children(node) def iscensored(self, rev): return self._revlog.iscensored(rev) def revision(self, node, _df=None, raw=False): return self._revlog.revision(node, _df=_df, raw=raw) def emitrevisions(self, nodes, nodesorder=None, revisiondata=False, assumehaveparentrevisions=False, deltaprevious=False): return self._revlog.emitrevisions( nodes, nodesorder=nodesorder, revisiondata=revisiondata, assumehaveparentrevisions=assumehaveparentrevisions, deltaprevious=deltaprevious) def addrevision(self, revisiondata, transaction, linkrev, p1, p2, node=None, flags=revlog.REVIDX_DEFAULT_FLAGS, cachedelta=None): return self._revlog.addrevision(revisiondata, transaction, linkrev, p1, p2, node=node, flags=flags, cachedelta=cachedelta) def addgroup(self, deltas, linkmapper, transaction, addrevisioncb=None): return self._revlog.addgroup(deltas, linkmapper, transaction, addrevisioncb=addrevisioncb) def getstrippoint(self, minlink): return self._revlog.getstrippoint(minlink) def strip(self, minlink, transaction): return self._revlog.strip(minlink, transaction) def censorrevision(self, tr, node, tombstone=b''): return self._revlog.censorrevision(tr, node, tombstone=tombstone) def files(self): return self._revlog.files() def read(self, node): return storageutil.filtermetadata(self.revision(node)) def add(self, text, meta, transaction, link, p1=None, p2=None): if meta or text.startswith('\1\n'): text = storageutil.packmeta(meta, text) return self.addrevision(text, transaction, link, p1, p2) def renamed(self, node): return storageutil.filerevisioncopied(self, node) def size(self, rev): """return the size of a given revision""" # for revisions with renames, we have to go the slow way node = self.node(rev) if self.renamed(node): return len(self.read(node)) if self.iscensored(rev): return 0 # XXX if self.read(node).startswith("\1\n"), this returns (size+4) return self._revlog.size(rev) def cmp(self, node, text): """compare text with a given file revision returns True if text is different than what is stored. """ return not storageutil.filedataequivalent(self, node, text) def verifyintegrity(self, state): return self._revlog.verifyintegrity(state) def storageinfo(self, exclusivefiles=False, sharedfiles=False, revisionscount=False, trackedsize=False, storedsize=False): return self._revlog.storageinfo( exclusivefiles=exclusivefiles, sharedfiles=sharedfiles, revisionscount=revisionscount, trackedsize=trackedsize, storedsize=storedsize) # TODO these aren't part of the interface and aren't internal methods. # Callers should be fixed to not use them. # Used by bundlefilelog, unionfilelog. @property def indexfile(self): return self._revlog.indexfile @indexfile.setter def indexfile(self, value): self._revlog.indexfile = value # Used by repo upgrade. def clone(self, tr, destrevlog, **kwargs): if not isinstance(destrevlog, filelog): raise error.ProgrammingError('expected filelog to clone()') return self._revlog.clone(tr, destrevlog._revlog, **kwargs) class narrowfilelog(filelog): """Filelog variation to be used with narrow stores.""" def __init__(self, opener, path, narrowmatch): super(narrowfilelog, self).__init__(opener, path) self._narrowmatch = narrowmatch def renamed(self, node): res = super(narrowfilelog, self).renamed(node) # Renames that come from outside the narrowspec are problematic # because we may lack the base text for the rename. This can result # in code attempting to walk the ancestry or compute a diff # encountering a missing revision. We address this by silently # removing rename metadata if the source file is outside the # narrow spec. # # A better solution would be to see if the base revision is available, # rather than assuming it isn't. # # An even better solution would be to teach all consumers of rename # metadata that the base revision may not be available. # # TODO consider better ways of doing this. if res and not self._narrowmatch(res[0]): return None return res def size(self, rev): # Because we have a custom renamed() that may lie, we need to call # the base renamed() to report accurate results. node = self.node(rev) if super(narrowfilelog, self).renamed(node): return len(self.read(node)) else: return super(narrowfilelog, self).size(rev) def cmp(self, node, text): different = super(narrowfilelog, self).cmp(node, text) # Because renamed() may lie, we may get false positives for # different content. Check for this by comparing against the original # renamed() implementation. if different: if super(narrowfilelog, self).renamed(node): t2 = self.read(node) return t2 != text return different