remotefilelog: import pruned-down remotefilelog extension from hg-experimental This is remotefilelog as of my recent patches for compatibility with current tip of hg, minus support for old versions of Mercurial and some FB-specific features like their treemanifest extension and fetching linkrev data from a patched phabricator. The file extutil.py moved from hgext3rd to remotefilelog. This is not yet ready to be landed, consider it a preview for now. Planned changes include: * replace lz4 with zstd * rename some capabilities, requirements and wireproto commands to mark them as experimental * consolidate bits of shallowutil with related functions (eg readfile) I'm certainly open to other (small) changes, but my rough mission is to land this largely as-is so we can use it as a model of the functionality we need going forward for lazy-fetching of file contents from a server. # no-check-commit because of a few foo_bar functions Differential Revision: https://phab.mercurial-scm.org/D4782

from __future__ import absolute_import

import struct

from mercurial.i18n import _

REQUIREMENT = "remotefilelog"

FILENAMESTRUCT = '!H'
FILENAMESIZE = struct.calcsize(FILENAMESTRUCT)

NODESIZE = 20
PACKREQUESTCOUNTSTRUCT = '!I'

NODECOUNTSTRUCT = '!I'
NODECOUNTSIZE = struct.calcsize(NODECOUNTSTRUCT)

PATHCOUNTSTRUCT = '!I'
PATHCOUNTSIZE = struct.calcsize(PATHCOUNTSTRUCT)

FILEPACK_CATEGORY=""
TREEPACK_CATEGORY="manifests"

ALL_CATEGORIES = [FILEPACK_CATEGORY, TREEPACK_CATEGORY]

# revision metadata keys. must be a single character.
METAKEYFLAG = 'f'  # revlog flag
METAKEYSIZE = 's'  # full rawtext size

def getunits(category):
    if category == FILEPACK_CATEGORY:
        return _("files")
    if category == TREEPACK_CATEGORY:
        return _("trees")

# Repack options passed to ``markledger``.
OPTION_PACKSONLY = 'packsonly'