hgext/fsmonitor/pywatchman/capabilities.py

revset: optimize for destination() being "inefficient"

destination() will scan through the whole subset and read extras for each
revision to get its source.

# Copyright 2015 Facebook, Inc.
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import re

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)
    failed = False
    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

# no-check-code -- this is a 3rd party library