mercurial/filelog.py

interfaces: introduce and use a protocol class for the `mpatch` module

See f2832de2a46c for details when this was done for the `bdiff` module.

Two things worth pointing out-

  1) The `cffi` module "inherits" the `pure` implementation of `patchedsize()`
     because of its wildcard import.
  2) It's odd that the `mpatchError` lives in both `pure` and `cext` modules.

I initially thought to move the exception into the new class, and make the
existing class name an alias to the class in the new location, but the exception
is created in C code by the `cext` module, so that won't work.  I don't think a
protocol class is approriate, because there's nothing special about the class to
distinguish from any other `Exception`.  Fortunately, nobody is catching this
exception in core, so we can kick the can down the road.

# 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 annotations

import typing

from typing import (
    Iterable,
    Iterator,
)

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,
    rewrite,
)


class FileLog:
    _revlog: revlog.revlog
    nullid: bytes
    _fix_issue6528: bool

    def __init__(self, opener, path, try_split=False):
        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,
            canonical_parent_order=False,  # see comment in revlog.py
            try_split=try_split,
        )
        # Full name of the user visible file, relative to the repository root.
        # Used by LFS.
        self._revlog.filename = path
        self.nullid = self._revlog.nullid
        opts = opener.options
        self._fix_issue6528 = opts.get(b'issue6528.fix-incoming', True)

    def get_revlog(self) -> revlog.revlog:
        """return an actual revlog instance if any

        This exist because a lot of code leverage the fact the underlying
        storage is a revlog for optimization, so giving simple way to access
        the revlog instance helps such code.
        """
        return self._revlog

    def __len__(self) -> int:
        return len(self._revlog)

    def __iter__(self) -> Iterator[int]:
        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):
        return self._revlog.revision(node)

    def rawdata(self, node):
        return self._revlog.rawdata(node)

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

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

        with self._revlog._writing(transaction):
            if self._fix_issue6528:
                deltas = rewrite.filter_delta_issue6528(self._revlog, deltas)

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

    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.iscensored(rev):
            return 0
        if self.renamed(node):
            return len(self.read(node))

        # XXX if self.read(node).startswith("\1\n"), this returns (size+4)
        # XXX See also basefilectx.cmp.
        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) -> Iterable[revlog.RevLogProblem]:
        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):
            msg = b'expected filelog to clone(), not %r'
            msg %= destrevlog
            raise error.ProgrammingError(msg)

        return self._revlog.clone(tr, destrevlog._revlog, **kwargs)


filelog = interfaceutil.implementer(repository.ifilestorage)(FileLog)

if typing.TYPE_CHECKING:
    filelog = FileLog


class narrowfilelog(filelog):
    """Filelog variation to be used with narrow stores."""

    def __init__(self, opener, path, narrowmatch, try_split=False):
        super(narrowfilelog, self).__init__(opener, path, try_split=try_split)
        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