mercurial/pure/base85.py

rebase: use scmutil.cleanupnodes (issue5606) (BC)

This patch migrates rebase to use scmutil.cleanupnodes API. It simplifies
the code and makes rebase code reusable inside a transaction.

This is a BC because the backup file is no longer strip-backup/*-backup.hg,
but strip-backup/*-rebase.hg. The latter looks more reasonable since the
directory name is "strip-backup" so there is no need to repeat "backup".

I think the backup file name change is probably fine as a BC, since we have
changed it before (aa4a1672583e) and didn't get complains. The end result
of this series will be a much more consistent and unified backup names:

  command  | old backup file suffix       | new backup file suffix
  -------------------------------------------------------------------
  amend    | amend-backup.hg              | amend.hg
  histedit | backup.hg (could be 2 files) | histedit.hg (single file)
  rebase   | backup.hg                    | rebase.hg
  strip    | backup.hg                    | backup.hg

(note: backup files are under .hg/strip-backup)

It also fixes issue5606 as a side effect because the new "delayedstrip" code
path will carefully examine nodes (safestriproots) to make sure orphaned
changesets won't get stripped by accident.

Some warning messages are changed to the new "warning: orphaned descendants
detected, not stripping HASHES", which provides more information about
exactly what changesets are left behind.

Another minor behavior change is when there is an obsoleted changeset with a
successor in the destination branch, bookmarks pointing to that obsoleted
changeset will not be moved. I have commented in test-rebase-obsolete.t
explaining why that is more desirable.

# base85.py: pure python base85 codec
#
# Copyright (C) 2009 Brendan Cully <[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

import struct

_b85chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
            "abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
_b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
_b85dec = {}

def _mkb85dec():
    for i, c in enumerate(_b85chars):
        _b85dec[c] = i

def b85encode(text, pad=False):
    """encode text in base85 format"""
    l = len(text)
    r = l % 4
    if r:
        text += '\0' * (4 - r)
    longs = len(text) >> 2
    words = struct.unpack('>%dL' % (longs), text)

    out = ''.join(_b85chars[(word // 52200625) % 85] +
                  _b85chars2[(word // 7225) % 7225] +
                  _b85chars2[word % 7225]
                  for word in words)

    if pad:
        return out

    # Trim padding
    olen = l % 4
    if olen:
        olen += 1
    olen += l // 4 * 5
    return out[:olen]

def b85decode(text):
    """decode base85-encoded text"""
    if not _b85dec:
        _mkb85dec()

    l = len(text)
    out = []
    for i in range(0, len(text), 5):
        chunk = text[i:i + 5]
        acc = 0
        for j, c in enumerate(chunk):
            try:
                acc = acc * 85 + _b85dec[c]
            except KeyError:
                raise ValueError('bad base85 character at position %d'
                                 % (i + j))
        if acc > 4294967295:
            raise ValueError('Base85 overflow in hunk starting at byte %d' % i)
        out.append(acc)

    # Pad final chunk if necessary
    cl = l % 5
    if cl:
        acc *= 85 ** (5 - cl)
        if cl > 1:
            acc += 0xffffff >> (cl - 2) * 8
        out[-1] = acc

    out = struct.pack('>%dL' % (len(out)), *out)
    if cl:
        out = out[:-(5 - cl)]

    return out