view mercurial/filelog.py @ 47387:75e1104f23a2

revlog: use dedicated code for reading sidedata

We are about to introduce a new, dedicated, file to store sidedata. Before doing so, we make sidedata reading go through different code as reading data chunk. This will simplify some of the complexity of the next changesets.

The reading is very simple right now and will need some improvement later to
reuse some of the caching strategy we use for the data file.

Differential Revision: https://phab.mercurial-scm.org/D10785

# filelog.py - file history class for mercurial
#
# Copyright 2005-2007 Olivia 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 .i18n import _
from .node import nullrev
from . import (
    error,
    revlog,
)
from .interfaces import (
    repository,
    util as interfaceutil,
)
from .utils import storageutil
from .revlogutils import (
    constants as revlog_constants,
)


@interfaceutil.implementer(repository.ifilestorage)
class filelog(object):
    def __init__(self, opener, path):
        self._revlog = revlog.revlog(
            opener,
            # XXX should use the unencoded path
            target=(revlog_constants.KIND_FILELOG, path),
            radix=b'/'.join((b'data', path)),
            censorable=True,
        )
        # Full name of the user visible file, relative to the repository root.
        # Used by LFS.
        self._revlog.filename = path
        self.nullid = self._revlog.nullid

    def __len__(self):
        return len(self._revlog)

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

    def hasnode(self, node):
        if node in (self.nullid, nullrev):
            return False

        try:
            self._revlog.rev(node)
            return True
        except (TypeError, ValueError, IndexError, error.LookupError):
            return False

    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.display_id
        )

    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 rawdata(self, node, _df=None):
        return self._revlog.rawdata(node, _df=_df)

    def emitrevisions(
        self,
        nodes,
        nodesorder=None,
        revisiondata=False,
        assumehaveparentrevisions=False,
        deltamode=repository.CG_DELTAMODE_STD,
        sidedata_helpers=None,
    ):
        return self._revlog.emitrevisions(
            nodes,
            nodesorder=nodesorder,
            revisiondata=revisiondata,
            assumehaveparentrevisions=assumehaveparentrevisions,
            deltamode=deltamode,
            sidedata_helpers=sidedata_helpers,
        )

    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,
        duplicaterevisioncb=None,
        maybemissingparents=False,
    ):
        if maybemissingparents:
            raise error.Abort(
                _(
                    b'revlog storage does not support missing '
                    b'parents write mode'
                )
            )

        return self._revlog.addgroup(
            deltas,
            linkmapper,
            transaction,
            addrevisioncb=addrevisioncb,
            duplicaterevisioncb=duplicaterevisioncb,
        )

    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(b'\1\n'):
            text = storageutil.packmeta(meta, text)
        rev = self.addrevision(text, transaction, link, p1, p2)
        return self.node(rev)

    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,
        )

    # Used by repo upgrade.
    def clone(self, tr, destrevlog, **kwargs):
        if not isinstance(destrevlog, filelog):
            raise error.ProgrammingError(b'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):
        # We don't call `super` because narrow parents can be buggy in case of a
        # ambiguous dirstate. Always take the slow path until there is a better
        # fix, see issue6150.

        # Censored files compare against the empty file.
        if self.iscensored(self.rev(node)):
            return text != b''

        return self.read(node) != text