# revlogdeltas.py - constant used for revlog logic

#

# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>

# Copyright 2018 Octobus <contact@octobus.net>

#

# 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

import struct

from ..interfaces import repository

### main revlog header

INDEX_HEADER = struct.Struct(b">I")

## revlog version

REVLOGV0 = 0

REVLOGV1 = 1

# Dummy value until file format is finalized.

REVLOGV2 = 0xDEAD

##  global revlog header flags

# Shared across v1 and v2.

FLAG_INLINE_DATA = 1 << 16

# Only used by v1, implied by v2.

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 = FLAG_INLINE_DATA

### individual entry

## index v0:

#  4 bytes: offset

#  4 bytes: compressed length

#  4 bytes: base rev

#  4 bytes: link rev

# 20 bytes: parent 1 nodeid

# 20 bytes: parent 2 nodeid

# 20 bytes: nodeid

INDEX_ENTRY_V0 = struct.Struct(b">4l20s20s20s")

## index v1

#  6 bytes: offset

#  2 bytes: flags

#  4 bytes: compressed length

#  4 bytes: uncompressed length

#  4 bytes: base rev

#  4 bytes: link rev

#  4 bytes: parent 1 rev

#  4 bytes: parent 2 rev

# 32 bytes: nodeid

INDEX_ENTRY_V1 = struct.Struct(b">Qiiiiii20s12x")

assert INDEX_ENTRY_V1.size == 32 * 2

#  6 bytes: offset

#  2 bytes: flags

#  4 bytes: compressed length

#  4 bytes: uncompressed length

#  4 bytes: base rev

#  4 bytes: link rev

#  4 bytes: parent 1 rev

#  4 bytes: parent 2 rev

# 32 bytes: nodeid

#  8 bytes: sidedata offset

#  4 bytes: sidedata compressed length

#  20 bytes: Padding to align to 96 bytes (see RevlogV2Plan wiki page)

INDEX_ENTRY_V2 = struct.Struct(b">Qiiiiii20s12xQi20x")

assert INDEX_ENTRY_V2.size == 32 * 3

# revlog index flags

# For historical reasons, revlog's internal flags were exposed via the

# wire protocol and are even exposed in parts of the storage APIs.

# revision has censor metadata, must be verified

REVIDX_ISCENSORED = repository.REVISION_FLAG_CENSORED

# revision hash does not match data (narrowhg)

REVIDX_ELLIPSIS = repository.REVISION_FLAG_ELLIPSIS

# revision data is stored externally

REVIDX_EXTSTORED = repository.REVISION_FLAG_EXTSTORED

# revision data contains extra metadata not part of the official digest

REVIDX_SIDEDATA = repository.REVISION_FLAG_SIDEDATA

# revision changes files in a way that could affect copy tracing.

REVIDX_HASCOPIESINFO = repository.REVISION_FLAG_HASCOPIESINFO

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_SIDEDATA,

    REVIDX_HASCOPIESINFO,

]

# bitmark for flags that could cause rawdata content change

REVIDX_RAWTEXT_CHANGING_FLAGS = (

    REVIDX_ISCENSORED | REVIDX_EXTSTORED | REVIDX_SIDEDATA

)

SPARSE_REVLOG_MAX_CHAIN_LENGTH = 1000