# Code dedicated to the exchange of obsolescence markers

#

# Copyright 2017 Pierre-Yves David <pierre-yves.david@ens-lyon.org>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from mercurial import (

    bundle2,

    error,

    exchange,

    extensions,

    node,

    obsolete,

    pushkey,

    util,

    wireprototypes,

    wireprotov1server

)

from mercurial.hgweb import common as hgwebcommon

from . import (

    exthelper,

    utility,

    obsdiscovery,

)

eh = exthelper.exthelper()

eh.merge(obsdiscovery.eh)

obsexcmsg = utility.obsexcmsg

eh.configitem(b'experimental', b'verbose-obsolescence-exchange', False)

_bestformat = max(obsolete.formats.keys())

#####################################################

### Support for subset specification in getbundle ###

#####################################################

# Adds support for the 'evo_obscommon' argument to getbundle This argument use

# the data recovered from the discovery to request only a subpart of the

# obsolete subtree.

@eh.uisetup

def addgetbundleargs(self):

    gboptsmap = wireprototypes.GETBUNDLE_ARGUMENTS

    gboptsmap[b'evo_obscommon'] = b'nodes'

    gboptsmap[b'evo_missing_nodes'] = b'nodes'

ARGUMENTS_LIMIT = 200

OVERFLOW_MSG = """obsmarkers differ for %d common nodes

|

| This might be too much for the remote HTTP server that doesn't accept

| arguments through POST request. (config: experimental.httppostargs=yes)

|

| Falling back to a less efficient fetching method.

|

| More efficient fetching method is possible and will be used in the future.

"""

@eh.wrapfunction(exchange, '_pullbundle2extraprepare')

def _addobscommontob2pull(orig, pullop, kwargs):

    ret = orig(pullop, kwargs)

    ui = pullop.repo.ui

    if (b'obsmarkers' in kwargs

        and pullop.remote.capable(b'_evoext_getbundle_obscommon')):

        boundaries = obsdiscovery.buildpullobsmarkersboundaries(pullop)

        use_common = True

        if b'missing' in boundaries:

            use_common = False

            missing = boundaries[b'missing']

            # using getattr since `limitedarguments` is missing

            # hg <= 5.0 (69921d02daaf)

            limitedarguments = getattr(pullop.remote, 'limitedarguments', False)

            if limitedarguments and len(missing) > ARGUMENTS_LIMIT:

                obsexcmsg(ui, OVERFLOW_MSG % len(missing))

                use_common = True

            else:

                if missing:

                    obsexcmsg(ui, b'request obsmarkers for %d common nodes\n'

                              % len(missing))

                kwargs[b'evo_missing_nodes'] = missing

        if use_common and b'common' in boundaries:

            common = boundaries[b'common']

            if common != pullop.common:

                obsexcmsg(ui, b'request obsmarkers for some common nodes\n')

            if common != [node.nullid]:

                kwargs[b'evo_obscommon'] = common

    return ret

def _getbundleobsmarkerpart(orig, bundler, repo, source, **kwargs):

    if not (set([r'evo_obscommon', r'evo_missing_nodes']) & set(kwargs)):

        return orig(bundler, repo, source, **kwargs)

    if kwargs.get('obsmarkers', False):

        heads = kwargs.get('heads')

        if r'evo_obscommon' in kwargs:

            if heads is None:

                heads = repo.heads()

            obscommon = kwargs.get('evo_obscommon', ())

            if obscommon:

                obsset = repo.unfiltered().set(b'::%ln - ::%ln', heads, obscommon)

            else:

                obsset = repo.unfiltered().set(b'::%ln', heads)

            subset = [c.node() for c in obsset]

        else:

            common = kwargs.get('common')

            subset = [c.node() for c in repo.unfiltered().set(b'only(%ln, %ln)', heads, common)]

            subset += kwargs['evo_missing_nodes']

        markers = repo.obsstore.relevantmarkers(subset)

        if util.safehasattr(bundle2, 'buildobsmarkerspart'):

            bundle2.buildobsmarkerspart(bundler, markers)

        else:

            exchange.buildobsmarkerspart(bundler, markers)

# manual wrap up in extsetup because of the wireproto.commands mapping

def _obscommon_capabilities(orig, repo, proto):

    """wrapper to advertise new capability"""

    caps = orig(repo, proto)

    if obsolete.isenabled(repo, obsolete.exchangeopt):

        caps = caps.data.split()

        caps.append(b'_evoext_getbundle_obscommon')

        caps.sort()

        caps = wireprototypes.bytesresponse(b' '.join(caps))

    return caps

@eh.extsetup

def extsetup_obscommon(ui):

    gboptsmap = wireprototypes.GETBUNDLE_ARGUMENTS

    gboptsmap[b'evo_obscommon'] = b'nodes'

    # wrap module content

    origfunc = exchange.getbundle2partsmapping[b'obsmarkers']

    def newfunc(*args, **kwargs):

        return _getbundleobsmarkerpart(origfunc, *args, **kwargs)

    exchange.getbundle2partsmapping[b'obsmarkers'] = newfunc

    extensions.wrapfunction(wireprotov1server, 'capabilities',

                            _obscommon_capabilities)

    # wrap command content

    oldcap, args = wireprotov1server.commands[b'capabilities']

    def newcap(repo, proto):

        return _obscommon_capabilities(oldcap, repo, proto)

    wireprotov1server.commands[b'capabilities'] = (newcap, args)

abortmsg = b"won't exchange obsmarkers through pushkey"

hint = b"upgrade your client or server to use the bundle2 protocol"

class HTTPCompatibleAbort(hgwebcommon.ErrorResponse, error.Abort):

    def __init__(self, message, code, hint=None):

        # initialisation of each class is a bit messy.

        # We explicitly do the dispatch

        hgwebcommon.ErrorResponse.__init__(self, 410, message)

        error.Abort.__init__(self, message, hint=hint)

def forbidpushkey(repo=None, key=None, old=None, new=None):

    """prevent exchange through pushkey"""

    err = HTTPCompatibleAbort(abortmsg, 410, hint=hint)

    raise err

def forbidlistkey(repo=None, key=None, old=None, new=None):

    """prevent exchange through pushkey"""

    if obsolete.isenabled(repo, obsolete.exchangeopt):

        err = HTTPCompatibleAbort(abortmsg, 410, hint=hint)

        raise err

    return {}

@eh.uisetup

def setuppushkeyforbidding(ui):

    pushkey._namespaces[b'obsolete'] = (forbidpushkey, forbidlistkey)