tests/flagprocessorext.py

errors: make exit codes class variables instead

Kyle pointed out to me that we can simply make the exit codes class
variables. Python provides some magic for making them accessible as
instance variables.

This also makes it easier to let subclasses of existing errors
override the exit codes by letting them simply define their own values
as class variables. That means that there's no need to pass them into
the superclass's constructor arguments, so the superclass doesn't need
to expose the them as arguments. (Making a subclass set a different
exit code for a subclass of `StorageError` was actually the goal with
my recent series.)

Differential Revision: https://phab.mercurial-scm.org/D10758

# coding=UTF-8

from __future__ import absolute_import

import base64
import zlib

from mercurial import (
    bundlecaches,
    changegroup,
    extensions,
    revlog,
    util,
)
from mercurial.revlogutils import flagutil

# 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 noopdonothingread(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(b'01')
    versions.discard(b'02')
    versions.add(b'03')
    return versions


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


def makewrappedfile(obj):
    class wrappedfile(obj.__class__):
        def addrevision(
            self,
            text,
            transaction,
            link,
            p1,
            p2,
            cachedelta=None,
            node=None,
            flags=flagutil.REVIDX_DEFAULT_FLAGS,
        ):
            if b'[NOOP]' in text:
                flags |= REVIDX_NOOP

            if b'[BASE64]' in text:
                flags |= REVIDX_BASE64

            if b'[GZIP]' in text:
                flags |= REVIDX_GZIP

            # This addrevision wrapper is meant to add a flag we will not have
            # transforms registered for, ensuring we handle this error case.
            if b'[FAIL]' in text:
                flags |= REVIDX_FAIL

            return super(wrappedfile, self).addrevision(
                text,
                transaction,
                link,
                p1,
                p2,
                cachedelta=cachedelta,
                node=node,
                flags=flags,
            )

    obj.__class__ = wrappedfile


def reposetup(ui, repo):
    class wrappingflagprocessorrepo(repo.__class__):
        def file(self, f):
            orig = super(wrappingflagprocessorrepo, self).file(f)
            makewrappedfile(orig)
            return orig

    repo.__class__ = wrappingflagprocessorrepo


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]
    flagutil.REVIDX_KNOWN_FLAGS |= util.bitsfrom(flags)
    revlog.REVIDX_FLAGS_ORDER.extend(flags)

    # Teach exchange to use changegroup 3
    for k in bundlecaches._bundlespeccontentopts.keys():
        bundlecaches._bundlespeccontentopts[k][b"cg.version"] = b"03"

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