# requirements.py - objects and functions related to repository requirements

#

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

#

# 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

# obsolete experimental requirements:

#  - manifestv2: An experimental new manifest format that allowed

#    for stem compression of long paths. Experiment ended up not

#    being successful (repository sizes went up due to worse delta

#    chains), and the code was deleted in 4.6.

GENERALDELTA_REQUIREMENT = b'generaldelta'

DOTENCODE_REQUIREMENT = b'dotencode'

STORE_REQUIREMENT = b'store'

FNCACHE_REQUIREMENT = b'fncache'

DIRSTATE_V2_REQUIREMENT = b'dirstate-v2'

# When narrowing is finalized and no longer subject to format changes,

# we should move this to just "narrow" or similar.

NARROW_REQUIREMENT = b'narrowhg-experimental'

# Enables sparse working directory usage

SPARSE_REQUIREMENT = b'exp-sparse'

# Enables the internal phase which is used to hide changesets instead

# of stripping them

INTERNAL_PHASE_REQUIREMENT = b'internal-phase'

# Stores manifest in Tree structure

TREEMANIFEST_REQUIREMENT = b'treemanifest'

REVLOGV1_REQUIREMENT = b'revlogv1'

# allow using ZSTD as compression engine for revlog content

REVLOG_COMPRESSION_ZSTD = b'revlog-compression-zstd'

# Increment the sub-version when the revlog v2 format changes to lock out old

# clients.

CHANGELOGV2_REQUIREMENT = b'exp-changelog-v2'

# Increment the sub-version when the revlog v2 format changes to lock out old

# clients.

REVLOGV2_REQUIREMENT = b'exp-revlogv2.2'

# A repository with the sparserevlog feature will have delta chains that

# can spread over a larger span. Sparse reading cuts these large spans into

# pieces, so that each piece isn't too big.

# Without the sparserevlog capability, reading from the repository could use

# huge amounts of memory, because the whole span would be read at once,

# including all the intermediate revisions that aren't pertinent for the chain.

# This is why once a repository has enabled sparse-read, it becomes required.

SPARSEREVLOG_REQUIREMENT = b'sparserevlog'

# A repository with the the copies-sidedata-changeset requirement will store

# copies related information in changeset's sidedata.

COPIESSDC_REQUIREMENT = b'exp-copies-sidedata-changeset'

# The repository use persistent nodemap for the changelog and the manifest.

NODEMAP_REQUIREMENT = b'persistent-nodemap'

# Denotes that the current repository is a share

SHARED_REQUIREMENT = b'shared'

# Denotes that current repository is a share and the shared source path is

# relative to the current repository root path

RELATIVE_SHARED_REQUIREMENT = b'relshared'

# A repository with share implemented safely. The repository has different

# store and working copy requirements i.e. both `.hg/requires` and

# `.hg/store/requires` are present.

SHARESAFE_REQUIREMENT = b'share-safe'

# Bookmarks must be stored in the `store` part of the repository and will be

# share accross shares

BOOKMARKS_IN_STORE_REQUIREMENT = b'bookmarksinstore'

# List of requirements which are working directory specific

# These requirements cannot be shared between repositories if they

# share the same store

# * sparse is a working directory specific functionality and hence working

#   directory specific requirement

# * SHARED_REQUIREMENT and RELATIVE_SHARED_REQUIREMENT are requirements which

#   represents that the current working copy/repository shares store of another

#   repo. Hence both of them should be stored in working copy

# * SHARESAFE_REQUIREMENT needs to be stored in working dir to mark that rest of

#   the requirements are stored in store's requires

# * DIRSTATE_V2_REQUIREMENT affects .hg/dirstate, of which there is one per

#   working directory.

WORKING_DIR_REQUIREMENTS = {

    SPARSE_REQUIREMENT,

    SHARED_REQUIREMENT,

    RELATIVE_SHARED_REQUIREMENT,

    SHARESAFE_REQUIREMENT,

    DIRSTATE_V2_REQUIREMENT,

}

# List of requirement that impact "stream-clone" (and hardlink clone) and

# cannot be changed in such cases.

#

# requirements not in this list are safe to be altered during stream-clone.

#

# note: the list is currently inherited from previous code and miss some relevant requirement while containing some irrelevant ones.

STREAM_FIXED_REQUIREMENTS = {

    BOOKMARKS_IN_STORE_REQUIREMENT,

    CHANGELOGV2_REQUIREMENT,

    COPIESSDC_REQUIREMENT,

    GENERALDELTA_REQUIREMENT,

    INTERNAL_PHASE_REQUIREMENT,

    NODEMAP_REQUIREMENT,

    REVLOG_COMPRESSION_ZSTD,

    REVLOGV1_REQUIREMENT,

    REVLOGV2_REQUIREMENT,

    SPARSEREVLOG_REQUIREMENT,

    TREEMANIFEST_REQUIREMENT,

}