view mercurial/requirements.py @ 47950:6961eca0b3ee

rhg: Port Python’s `ui.configlist` as `Config::get_list`

This new method is not used yet outside of its own unit tests,
so this changeset should make no observable change.

The Rust parser implementation attempts to exactly replicate the behavior of
the Python one, even in edge cases where that behavior is… surprising.
New unit tests capture some of these edge cases.

This started as a line-by-line port. The main changes are:

* Pass around a parser mode enum instead of parser functions
* Inline the whole parser into one function
* Use `[u8]::get` which returns an `Option`,
  instead of indexing  after explicitly checking the length.

Differential Revision: https://phab.mercurial-scm.org/D11389

# requirements.py - objects and functions related to repository requirements
#
# Copyright 2005-2007 Olivia Mackall <[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

GENERALDELTA_REQUIREMENT = b'generaldelta'
DOTENCODE_REQUIREMENT = b'dotencode'
STORE_REQUIREMENT = b'store'
FNCACHE_REQUIREMENT = b'fncache'

DIRSTATE_V2_REQUIREMENT = b'exp-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'

# 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'

# 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,
}