hgext/fsmonitor/pywatchman/capabilities.py

persistent-nodemap: document the feature in `hg help config.format`

This is necessary before we advertise the feature more.

Differential Revision: https://phab.mercurial-scm.org/D9755

# Copyright 2015 Facebook, Inc.
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# modification, are permitted provided that the following conditions are met:
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# no unicode literals
from __future__ import absolute_import, division, print_function


def parse_version(vstr):
    res = 0
    for n in vstr.split("."):
        res = res * 1000
        res = res + int(n)
    return res


cap_versions = {
    "cmd-watch-del-all": "3.1.1",
    "cmd-watch-project": "3.1",
    "relative_root": "3.3",
    "term-dirname": "3.1",
    "term-idirname": "3.1",
    "wildmatch": "3.7",
}


def check(version, name):
    if name in cap_versions:
        return version >= parse_version(cap_versions[name])
    return False


def synthesize(vers, opts):
    """Synthesize a capability enabled version response
    This is a very limited emulation for relatively recent feature sets
    """
    parsed_version = parse_version(vers["version"])
    vers["capabilities"] = {}
    for name in opts["optional"]:
        vers["capabilities"][name] = check(parsed_version, name)

    for name in opts["required"]:
        have = check(parsed_version, name)
        vers["capabilities"][name] = have
        if not have:
            vers["error"] = (
                "client required capability `"
                + name
                + "` is not supported by this server"
            )
    return vers