annotate mercurial/revlogutils/constants.py @ 39594:bdb41eaa8b59

snapshot: fix line order when skipping over empty deltas

The code movement in 37957e07138c introduced an error.

Since 8f83a953dddf, we discarded some revisions because they are identical to
their delta base (and use that delta base instead). That logic is good,
however, in 37957e07138c we mixed up the order of two line, adding the "new"
revision to the set of already tested one, instead of the discarded one. So in
practice, we were never investigating any revisions in a chain starting with
an empty delta. Creating significantly worst delta chain (eg: Mercurial's
manifest move goes from about 60MB up to about 80MB).

# revlogdeltas.py - constant used for revlog logic
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
# Copyright 2018 Octobus <[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.
"""Helper class to compute deltas stored inside revlogs"""

from __future__ import absolute_import

from .. import (
    util,
)

# revlog header flags
REVLOGV0 = 0
REVLOGV1 = 1
# Dummy value until file format is finalized.
# Reminder: change the bounds check in revlog.__init__ when this is changed.
REVLOGV2 = 0xDEAD
FLAG_INLINE_DATA = (1 << 16)
FLAG_GENERALDELTA = (1 << 17)
REVLOG_DEFAULT_FLAGS = FLAG_INLINE_DATA
REVLOG_DEFAULT_FORMAT = REVLOGV1
REVLOG_DEFAULT_VERSION = REVLOG_DEFAULT_FORMAT | REVLOG_DEFAULT_FLAGS
REVLOGV1_FLAGS = FLAG_INLINE_DATA | FLAG_GENERALDELTA
REVLOGV2_FLAGS = REVLOGV1_FLAGS

# revlog index flags
REVIDX_ISCENSORED = (1 << 15) # revision has censor metadata, must be verified
REVIDX_ELLIPSIS = (1 << 14) # revision hash does not match data (narrowhg)
REVIDX_EXTSTORED = (1 << 13) # revision data is stored externally
REVIDX_DEFAULT_FLAGS = 0
# stable order in which flags need to be processed and their processors applied
REVIDX_FLAGS_ORDER = [
    REVIDX_ISCENSORED,
    REVIDX_ELLIPSIS,
    REVIDX_EXTSTORED,
]
REVIDX_KNOWN_FLAGS = util.bitsfrom(REVIDX_FLAGS_ORDER)
# bitmark for flags that could cause rawdata content change
REVIDX_RAWTEXT_CHANGING_FLAGS = REVIDX_ISCENSORED | REVIDX_EXTSTORED

SPARSE_REVLOG_MAX_CHAIN_LENGTH = 1000