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
line wrap: on
line source

# 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)