Mercurial > public > mercurial-scm > hg
view mercurial/filelog.py @ 37497:1541e1a8e87d
filelog: wrap revlog instead of inheriting it (API)
The revlog base class exposes a ton of methods. Inheriting the
revlog class for filelog will make it difficult to expose a
clean interface. There will be abstraction violations.
This commit breaks the inheritance of revlog by the filelog
class. Filelog instances now contain a reference to a revlog
instance. Various properties and methods are now proxied to
that instance.
There is precedence for doing this: manifestlog does something
similar. Although, manifestlog has a cleaner interface than
filelog. We'll get there with filelog...
The new filelog class exposes a handful of extra properties and
methods that aren't part of the declared filelog interface.
Every extra item was added in order to get a test to pass. The
set of tests that failed without these extra proxies has
significant overlap with the set of tests that don't work with
the simple store repo. There should be no surprise there.
Hopefully the hardest part about this commit to review are the
changes to bundlerepo and unionrepo. Both repository types
define a custom revlog or revlog-like class and then have a
custom filelog that inherits from both filelog and their custom
revlog. This code has been changed so the filelog types don't
inherit from revlog. Instead, they replace the revlog instance
on the created filelog. This is super hacky. I plan to fix this
in a future commit by parameterizing filelog.__init__.
Because Python function call overhead is a thing, this change
could impact performance by introducing a nearly empty proxy
function for various methods and properties. I would gladly
measure the performance impact of it, but I'm not sure what
operations have tight loops over filelog attribute lookups
or function calls. I know some of the DAG traversal code can
be sensitive about the performance of e.g. parentrevs(). However,
many of these functions are implemented on the revlog class and
therefore have direct access to self.parentrevs() and aren't
going through a proxy.
.. api::
filelog.filelog is now a standalone class and doesn't inherit
from revlog. Instead, it wraps a revlog instance at self._revlog.
This change was made in an attempt to formalize storage APIs and
prevent revlog implementation details leaking through to callers.
Differential Revision: https://phab.mercurial-scm.org/D3154
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Fri, 06 Apr 2018 22:39:58 -0700 |
parents | 65250a66b55c |
children | 856f381ad74b |
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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 .thirdparty.zope import ( interface as zi, ) from . import ( error, repository, revlog, ) @zi.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 self.filename = path self.index = self._revlog.index self.version = self._revlog.version self.storedeltachains = self._revlog.storedeltachains self._generaldelta = self._revlog._generaldelta 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 self._revlog.lookup(node) def linkrev(self, rev): return self._revlog.linkrev(rev) def flags(self, rev): return self._revlog.flags(rev) def commonancestorsheads(self, node1, node2): return self._revlog.commonancestorsheads(node1, node2) def descendants(self, revs): return self._revlog.descendants(revs) def headrevs(self): return self._revlog.headrevs() def heads(self, start=None, stop=None): return self._revlog.heads(start, stop) def children(self, node): return self._revlog.children(node) def deltaparent(self, rev): return self._revlog.deltaparent(rev) def candelta(self, baserev, rev): return self._revlog.candelta(baserev, rev) def iscensored(self, rev): return self._revlog.iscensored(rev) def rawsize(self, rev): return self._revlog.rawsize(rev) def checkhash(self, text, node, p1=None, p2=None, rev=None): return self._revlog.checkhash(text, node, p1=p1, p2=p2, rev=rev) def revision(self, node, _df=None, raw=False): return self._revlog.revision(node, _df=_df, raw=raw) def revdiff(self, rev1, rev2): return self._revlog.revdiff(rev1, rev2) 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 files(self): return self._revlog.files() def checksize(self): return self._revlog.checksize() def read(self, node): t = self.revision(node) if not t.startswith('\1\n'): return t s = t.index('\1\n', 2) return t[s + 2:] def add(self, text, meta, transaction, link, p1=None, p2=None): if meta or text.startswith('\1\n'): text = revlog.packmeta(meta, text) return self.addrevision(text, transaction, link, p1, p2) def renamed(self, node): if self.parents(node)[0] != revlog.nullid: return False t = self.revision(node) m = revlog.parsemeta(t)[0] if m and "copy" in m: return (m["copy"], revlog.bin(m["copyrev"])) return False 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. """ 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 @property def filename(self): return self._revlog.filename @filename.setter def filename(self, value): self._revlog.filename = value # TODO these aren't part of the interface and aren't internal methods. # Callers should be fixed to not use them. @property def indexfile(self): return self._revlog.indexfile @indexfile.setter def indexfile(self, value): self._revlog.indexfile = value @property def datafile(self): return self._revlog.datafile @property def opener(self): return self._revlog.opener @property def _lazydeltabase(self): return self._revlog._lazydeltabase @_lazydeltabase.setter def _lazydeltabase(self, value): self._revlog._lazydeltabase = value @property def _aggressivemergedeltas(self): return self._revlog._aggressivemergedeltas @_aggressivemergedeltas.setter def _aggressivemergedeltas(self, value): self._revlog._aggressivemergedeltas = value @property def _inline(self): return self._revlog._inline @property def _withsparseread(self): return getattr(self._revlog, '_withsparseread', False) @property def _srmingapsize(self): return self._revlog._srmingapsize @property def _srdensitythreshold(self): return self._revlog._srdensitythreshold def _deltachain(self, rev, stoprev=None): return self._revlog._deltachain(rev, stoprev) def chainbase(self, rev): return self._revlog.chainbase(rev) def chainlen(self, rev): return self._revlog.chainlen(rev) 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) def start(self, rev): return self._revlog.start(rev) def end(self, rev): return self._revlog.end(rev) def length(self, rev): return self._revlog.length(rev) def compress(self, data): return self._revlog.compress(data) def _addrevision(self, *args, **kwargs): return self._revlog._addrevision(*args, **kwargs)