mercurial/filelog.py

lfs: access revlog directly

LFS is monkeypatching filelog.filelog and is then accessing
various filelog attributes in the monkeypatched function. This is all
fine.

But some of the attributes being accessed by LFS are revlog centric
and shouldn't be exposed on the file storage interface.

This commit changes the monkeypatched functions to access proxied
attributes on self._revlog instead of self.

This should be safe to do because non-revlog repositories should not
be using filelog instances: instead they should have a separate class
to represent file storage. So it is reasonable for LFS to assume the
_revlog attribute exists and points to a revlog.

Differential Revision: https://phab.mercurial-scm.org/D4714

# filelog.py - file history class for mercurial
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# 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,
)

@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.filename = path
        # Used by repo upgrade.
        self.index = self._revlog.index
        # Used by changegroup generation.
        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)

    # Used by verify.
    def flags(self, rev):
        return self._revlog.flags(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 deltaparent(self, rev):
        return self._revlog.deltaparent(rev)

    def iscensored(self, rev):
        return self._revlog.iscensored(rev)

    # Used by verify.
    def rawsize(self, rev):
        return self._revlog.rawsize(rev)

    # Might be unused.
    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 emitrevisiondeltas(self, requests):
        return self._revlog.emitrevisiondeltas(requests)

    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(node, tombstone=tombstone)

    def files(self):
        return self._revlog.files()

    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]
        # copy and copyrev occur in pairs. In rare cases due to bugs,
        # one can occur without the other.
        if m and "copy" in m and "copyrev" 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

    def verifyintegrity(self, state):
        return self._revlog.verifyintegrity(state)

    # TODO these aren't part of the interface and aren't internal methods.
    # Callers should be fixed to not use them.

    # Used by LFS.
    @property
    def filename(self):
        return self._revlog.filename

    @filename.setter
    def filename(self, value):
        self._revlog.filename = value

    # 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.
    @property
    def opener(self):
        return self._revlog.opener

    # 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