revlog: skip over empty revision when looking for delta base
There is no point in keeping an empty revision in the middle of a chain since
they won't contribute any data. So we filter them out when looking for a valid
base delta.
# 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