tests/flagprocessorext.py

debug: add a method to check the state of, and built an SSL cert chain

This is only useful on Windows, and avoids the need to use Internet Explorer to
build the certificate chain.  I can see this being extended in the future to
print information about the certificate(s) to help debug issues on any platform.
Maybe even perform some of the python checks listed on the secure connections
wiki page.  But for now, all I need is 1) a command that can be invoked in a
setup script to ensure the certificate is installed, and 2) a command that the
user can run if/when a certificate changes in the future.

It would have been nice to leverage the sslutil library to pick up host specific
settings, but attempting to use sslutil.wrapsocket() failed the
'not sslsocket.cipher()' check in it and aborted.

The output is a little more chatty than some commands, but I've seen the update
take 10+ seconds, and this is only a debug command.

# coding=UTF-8

from __future__ import absolute_import

import base64
import zlib

from mercurial import (
    changegroup,
    exchange,
    extensions,
    filelog,
    revlog,
    util,
)

# Test only: These flags are defined here only in the context of testing the
# behavior of the flag processor. The canonical way to add flags is to get in
# touch with the community and make them known in revlog.
REVIDX_NOOP = (1 << 3)
REVIDX_BASE64 = (1 << 2)
REVIDX_GZIP = (1 << 1)
REVIDX_FAIL = 1

def validatehash(self, text):
    return True

def bypass(self, text):
    return False

def noopdonothing(self, text):
    return (text, True)

def b64encode(self, text):
    return (base64.b64encode(text), False)

def b64decode(self, text):
    return (base64.b64decode(text), True)

def gzipcompress(self, text):
    return (zlib.compress(text), False)

def gzipdecompress(self, text):
    return (zlib.decompress(text), True)

def supportedoutgoingversions(orig, repo):
    versions = orig(repo)
    versions.discard('01')
    versions.discard('02')
    versions.add('03')
    return versions

def allsupportedversions(orig, ui):
    versions = orig(ui)
    versions.add('03')
    return versions

def noopaddrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
    if '[NOOP]' in text:
        flags |= REVIDX_NOOP
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def b64addrevision(orig, self, text, transaction, link, p1, p2,
                   cachedelta=None, node=None,
                   flags=revlog.REVIDX_DEFAULT_FLAGS):
    if '[BASE64]' in text:
        flags |= REVIDX_BASE64
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def gzipaddrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
    if '[GZIP]' in text:
        flags |= REVIDX_GZIP
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def failaddrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
    # This addrevision wrapper is meant to add a flag we will not have
    # transforms registered for, ensuring we handle this error case.
    if '[FAIL]' in text:
        flags |= REVIDX_FAIL
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def extsetup(ui):
    # Enable changegroup3 for flags to be sent over the wire
    wrapfunction = extensions.wrapfunction
    wrapfunction(changegroup,
                 'supportedoutgoingversions',
                 supportedoutgoingversions)
    wrapfunction(changegroup,
                 'allsupportedversions',
                 allsupportedversions)

    # Teach revlog about our test flags
    flags = [REVIDX_NOOP, REVIDX_BASE64, REVIDX_GZIP, REVIDX_FAIL]
    revlog.REVIDX_KNOWN_FLAGS |= util.bitsfrom(flags)
    revlog.REVIDX_FLAGS_ORDER.extend(flags)

    # Teach exchange to use changegroup 3
    for k in exchange._bundlespeccgversions.keys():
        exchange._bundlespeccgversions[k] = '03'

    # Add wrappers for addrevision, responsible to set flags depending on the
    # revision data contents.
    wrapfunction(filelog.filelog, 'addrevision', noopaddrevision)
    wrapfunction(filelog.filelog, 'addrevision', b64addrevision)
    wrapfunction(filelog.filelog, 'addrevision', gzipaddrevision)
    wrapfunction(filelog.filelog, 'addrevision', failaddrevision)

    # Register flag processors for each extension
    revlog.addflagprocessor(
        REVIDX_NOOP,
        (
            noopdonothing,
            noopdonothing,
            validatehash,
        )
    )
    revlog.addflagprocessor(
        REVIDX_BASE64,
        (
            b64decode,
            b64encode,
            bypass,
        ),
    )
    revlog.addflagprocessor(
        REVIDX_GZIP,
        (
            gzipdecompress,
            gzipcompress,
            bypass
        )
    )