view tests/flagprocessorext.py @ 47682:78f7f0d490ee

dirstate-v2: Move fixed-size tree metadata into the docket file

Before this changeset, the dirstate-v2 data file contained not only nodes
and paths that may be reused when appending to an existing file,
but also some fixed-size metadata that applies to the entire tree
and was added at the end of the data file for every append.

This moves that metadata into the docket file, so that repeated "append"
operations without meaningful changes don’t actually need to grow any file.

Differential Revision: https://phab.mercurial-scm.org/D11098

# 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
from mercurial.interfaces import repository

# 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)
    repository.REVISION_FLAGS_KNOWN |= 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)
    )