# narrowrevlog.py - revlog storing irrelevant nodes as "ellipsis" nodes

#

# Copyright 2017 Google, Inc.

#

# 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 mercurial import (

   revlog,

   util,

)

def readtransform(self, text):

    return text, False

def writetransform(self, text):

    return text, False

def rawtransform(self, text):

    return False

revlog.addflagprocessor(revlog.REVIDX_ELLIPSIS,

                        (readtransform, writetransform, rawtransform))

def setup():

    # We just wanted to add the flag processor, which is done at module

    # load time.

    pass

def makenarrowfilelog(fl, narrowmatch):

    class narrowfilelog(fl.__class__):

        def renamed(self, node):

            # Renames that come from outside the narrowspec are

            # problematic at least for git-diffs, because we lack the

            # base text for the rename. This logic was introduced in

            # 3cd72b1 of narrowhg (authored by martinvonz, reviewed by

            # adgar), but that revision doesn't have any additional

            # commentary on what problems we can encounter.

            m = super(narrowfilelog, self).renamed(node)

            if m and not narrowmatch(m[0]):

                return None

            return m

        def size(self, rev):

            # We take advantage of the fact that remotefilelog

            # lacks a node() method to just skip the

            # rename-checking logic when on remotefilelog. This

            # might be incorrect on other non-revlog-based storage

            # engines, but for now this seems to be fine.

            #

            # TODO: when remotefilelog is in core, improve this to

            # explicitly look for remotefilelog instead of cheating

            # with a hasattr check.

            if util.safehasattr(self, 'node'):

                node = self.node(rev)

                # Because renamed() is overridden above to

                # sometimes return None even if there is metadata

                # in the revlog, size can be incorrect for

                # copies/renames, so we need to make sure we call

                # the super class's implementation of renamed()

                # for the purpose of size calculation.

                if super(narrowfilelog, self).renamed(node):

                    return len(self.read(node))

            return super(narrowfilelog, self).size(rev)

        def cmp(self, node, text):

            different = super(narrowfilelog, self).cmp(node, text)

            if different:

                # Similar to size() above, if the file was copied from

                # a file outside the narrowspec, the super class's

                # would have returned True because we tricked it into

                # thinking that the file was not renamed.

                if super(narrowfilelog, self).renamed(node):

                    t2 = self.read(node)

                    return t2 != text

            return different

    fl.__class__ = narrowfilelog