view hgext3rd/topic/topicmap.py @ 2653:13313d0cab71

topicmap: massive rework

Massively rework the way we build and use topicmap. This bring massive performance
benefit.

Topic map use to be a fully independant thing that we would switch on and off
globaly. The caching on disk was broken so the performance were atrocious.

Intead, now the topic are inherited from the 'immutable' map. We gave up on
storing them on disk for now since the mutable set is usually small enough.

The activation is done by hacking new "filter" on the repository and detection
when they are one. This is hacky but core is hard to wrap here.

Overall this whole wrapping is really scary and we should massage core API to
help it.

import contextlib
import hashlib

from mercurial.node import nullid
from mercurial import (
    branchmap,
    changegroup,
    cmdutil,
    extensions,
    repoview,
)

basefilter = set(['base', 'immutable'])
def topicfilter(name):
    """return a "topic" version of a filter level"""
    if name in basefilter:
        return name
    elif name is None:
        return None
    elif name.endswith('-topic'):
        return name
    else:
        return name + '-topic'

def istopicfilter(filtername):
    if filtername is None:
        return False
    return filtername.endswith('-topic')

def gettopicrepo(repo):
    filtername = topicfilter(repo.filtername)
    if filtername == repo.filtername:
        return repo
    return repo.filtered(filtername)

def _setuptopicfilter(ui):
    """extend the filter related mapping with topic related one"""
    funcmap = repoview.filtertable
    partialmap = branchmap.subsettable

    # filter level not affected by topic that we should not override

    for plainname in list(funcmap):
        newfilter = topicfilter(plainname)
        if newfilter == plainname:
            continue

        def revsfunc(repo, name=plainname):
            return repoview.filterrevs(repo, name)

        base = topicfilter(partialmap[plainname])

        if newfilter not in funcmap:
            funcmap[newfilter] = revsfunc
            partialmap[newfilter] = base
    funcmap['unfiltered-topic'] = lambda repo: frozenset()
    partialmap['unfiltered-topic'] = 'visible-topic'

def _phaseshash(repo, maxrev):
    """uniq ID for a phase matching a set of rev"""
    revs = set()
    cl = repo.changelog
    fr = cl.filteredrevs
    nm = cl.nodemap
    for roots in repo._phasecache.phaseroots[1:]:
        for n in roots:
            r = nm.get(n)
            if r not in fr and r < maxrev:
                revs.add(r)
    key = nullid
    revs = sorted(revs)
    if revs:
        s = hashlib.sha1()
        for rev in revs:
            s.update('%s;' % rev)
        key = s.digest()
    return key

def modsetup(ui):
    """call at uisetup time to install various wrappings"""
    _setuptopicfilter(ui)
    _wrapbmcache(ui)
    extensions.wrapfunction(changegroup.cg1unpacker, 'apply', cgapply)
    extensions.wrapfunction(cmdutil, 'commitstatus', commitstatus)

def cgapply(orig, self, repo, *args, **kwargs):
    """make sure a topicmap is used when applying a changegroup"""
    other = repo.filtered(topicfilter(repo.filtername))
    return orig(self, other, *args, **kwargs)

def commitstatus(orig, repo, node, branch, bheads=None, opts=None):
    # wrap commit status use the topic branch heads
    ctx = repo[node]
    if ctx.topic() and ctx.branch() == branch:
        subbranch = "%s:%s" % (branch, ctx.topic())
        bheads = repo.branchheads("%s:%s" % (subbranch, ctx.topic()))
    return orig(repo, node, branch, bheads=bheads, opts=opts)

def _wrapbmcache(ui):
    class topiccache(_topiccache, branchmap.branchcache):
        pass
    branchmap.branchcache = topiccache
    extensions.wrapfunction(branchmap, 'updatecache', _wrapupdatebmcache)

def _wrapupdatebmcache(orig, repo):
    previous = repo._autobranchmaptopic
    try:
        repo._autobranchmaptopic = False
        return orig(repo)
    finally:
        repo._autobranchmaptopic = previous

# needed to prevent reference used for 'super()' call using in branchmap.py to
# no go into cycle. (yes, URG)
_oldbranchmap = branchmap.branchcache

@contextlib.contextmanager
def oldbranchmap():
    previous = branchmap.branchcache
    try:
        branchmap.branchcache = _oldbranchmap
        yield
    finally:
        branchmap.branchcache = previous

class _topiccache(object): # combine me with branchmap.branchcache

    def __init__(self, *args, **kwargs):
        # super() call may fail otherwise
        with oldbranchmap():
            super(_topiccache, self).__init__(*args, **kwargs)
        self.phaseshash = None

    def copy(self):
        """return an deep copy of the branchcache object"""
        new = self.__class__(self, self.tipnode, self.tiprev, self.filteredhash,
                             self._closednodes)
        new.phaseshash = self.phaseshash
        return new

    def branchtip(self, branch, topic=''):
        '''Return the tipmost open head on branch head, otherwise return the
        tipmost closed head on branch.
        Raise KeyError for unknown branch.'''
        if topic:
            branch = '%s:%s' % (branch, topic)
        return super(_topiccache, self).branchtip(branch)

    def branchheads(self, branch, closed=False, topic=''):
        if topic:
            branch = '%s:%s' % (branch, topic)
        return super(_topiccache, self).branchheads(branch, closed=closed)

    def validfor(self, repo):
        """Is the cache content valid regarding a repo

        - False when cached tipnode is unknown or if we detect a strip.
        - True when cache is up to date or a subset of current repo."""
        valid = super(_topiccache, self).validfor(repo)
        if not valid:
            return False
        elif not istopicfilter(repo.filtername) or self.phaseshash is None:
            # phasehash at None means this is a branchmap
            # come from non topic thing
            return True
        else:
            try:
                valid = self.phaseshash == _phaseshash(repo, self.tiprev)
                return valid
            except IndexError:
                return False

    def write(self, repo):
        # we expect mutable set to be small enough to be that computing it all
        # the time will be fast enough
        if not istopicfilter(repo.filtername):
            super(_topiccache, self).write(repo)

    def update(self, repo, revgen):
        """Given a branchhead cache, self, that may have extra nodes or be
        missing heads, and a generator of nodes that are strictly a superset of
        heads missing, this function updates self to be correct.
        """
        if not istopicfilter(repo.filtername):
            return super(_topiccache, self).update(repo, revgen)
        unfi = repo.unfiltered()
        oldgetbranchinfo = unfi.revbranchcache().branchinfo

        def branchinfo(r):
            info = oldgetbranchinfo(r)
            topic = ''
            ctx = unfi[r]
            if ctx.mutable():
                topic = ctx.topic()
            branch = info[0]
            if topic:
                branch = '%s:%s' % (branch, topic)
            return (branch, info[1])
        try:
            unfi.revbranchcache().branchinfo = branchinfo
            super(_topiccache, self).update(repo, revgen)
            self.phaseshash = _phaseshash(repo, self.tiprev)
        finally:
            unfi.revbranchcache().branchinfo = oldgetbranchinfo