git: skeleton of a new extension to _directly_ operate on git repos
This is based in part of work I did years ago in hgit, but it's mostly
new code since I'm using pygit2 instead of dulwich and the hg storage
interfaces have improved. Some cleanup of old hgit code by Pulkit,
which I greatly appreciate.
test-git-interop.t does not cover a whole lot of cases, but it
passes. It includes status, diff, making a new commit, and `hg annotate`
working on the git repository.
This is _not_ (yet) production quality code: this is an
experiment. Known technical debt lurking in this implementation:
* Writing bookmarks just totally ignores transactions.
* The way progress is threaded down into the gitstore is awful.
* Ideally we'd find a way to incrementally reindex DAGs. I'm not sure
how to do that efficiently, so we might need a "known only fast-forwards"
mode on the DAG indexer for use on `hg commit` and friends.
* We don't even _try_ to do anything reasonable for `hg pull` or `hg push`.
* Mercurial need an interface for the changelog type.
Tests currently require git 2.24 as far as I'm aware: `git status` has
some changed output that I didn't try and handle in a compatible way.
This patch has produced some interesting cleanups, most recently on
the manifest type. I expect continuing down this road will produce
other meritorious cleanups throughout our code.
Differential Revision: https://phab.mercurial-scm.org/D6734
# shallowrepo.py - shallow repository that uses remote filelogs
#
# Copyright 2013 Facebook, Inc.
#
# 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
import os
from mercurial.i18n import _
from mercurial.node import hex, nullid, nullrev
from mercurial import (
encoding,
error,
localrepo,
match,
pycompat,
scmutil,
sparse,
util,
)
from mercurial.utils import procutil
from . import (
connectionpool,
constants,
contentstore,
datapack,
fileserverclient,
historypack,
metadatastore,
remotefilectx,
remotefilelog,
shallowutil,
)
# These make*stores functions are global so that other extensions can replace
# them.
def makelocalstores(repo):
"""In-repo stores, like .hg/store/data; can not be discarded."""
localpath = os.path.join(repo.svfs.vfs.base, b'data')
if not os.path.exists(localpath):
os.makedirs(localpath)
# Instantiate local data stores
localcontent = contentstore.remotefilelogcontentstore(
repo, localpath, repo.name, shared=False
)
localmetadata = metadatastore.remotefilelogmetadatastore(
repo, localpath, repo.name, shared=False
)
return localcontent, localmetadata
def makecachestores(repo):
"""Typically machine-wide, cache of remote data; can be discarded."""
# Instantiate shared cache stores
cachepath = shallowutil.getcachepath(repo.ui)
cachecontent = contentstore.remotefilelogcontentstore(
repo, cachepath, repo.name, shared=True
)
cachemetadata = metadatastore.remotefilelogmetadatastore(
repo, cachepath, repo.name, shared=True
)
repo.sharedstore = cachecontent
repo.shareddatastores.append(cachecontent)
repo.sharedhistorystores.append(cachemetadata)
return cachecontent, cachemetadata
def makeremotestores(repo, cachecontent, cachemetadata):
"""These stores fetch data from a remote server."""
# Instantiate remote stores
repo.fileservice = fileserverclient.fileserverclient(repo)
remotecontent = contentstore.remotecontentstore(
repo.ui, repo.fileservice, cachecontent
)
remotemetadata = metadatastore.remotemetadatastore(
repo.ui, repo.fileservice, cachemetadata
)
return remotecontent, remotemetadata
def makepackstores(repo):
"""Packs are more efficient (to read from) cache stores."""
# Instantiate pack stores
packpath = shallowutil.getcachepackpath(repo, constants.FILEPACK_CATEGORY)
packcontentstore = datapack.datapackstore(repo.ui, packpath)
packmetadatastore = historypack.historypackstore(repo.ui, packpath)
repo.shareddatastores.append(packcontentstore)
repo.sharedhistorystores.append(packmetadatastore)
shallowutil.reportpackmetrics(
repo.ui, b'filestore', packcontentstore, packmetadatastore
)
return packcontentstore, packmetadatastore
def makeunionstores(repo):
"""Union stores iterate the other stores and return the first result."""
repo.shareddatastores = []
repo.sharedhistorystores = []
packcontentstore, packmetadatastore = makepackstores(repo)
cachecontent, cachemetadata = makecachestores(repo)
localcontent, localmetadata = makelocalstores(repo)
remotecontent, remotemetadata = makeremotestores(
repo, cachecontent, cachemetadata
)
# Instantiate union stores
repo.contentstore = contentstore.unioncontentstore(
packcontentstore,
cachecontent,
localcontent,
remotecontent,
writestore=localcontent,
)
repo.metadatastore = metadatastore.unionmetadatastore(
packmetadatastore,
cachemetadata,
localmetadata,
remotemetadata,
writestore=localmetadata,
)
fileservicedatawrite = cachecontent
fileservicehistorywrite = cachemetadata
repo.fileservice.setstore(
repo.contentstore,
repo.metadatastore,
fileservicedatawrite,
fileservicehistorywrite,
)
shallowutil.reportpackmetrics(
repo.ui, b'filestore', packcontentstore, packmetadatastore
)
def wraprepo(repo):
class shallowrepository(repo.__class__):
@util.propertycache
def name(self):
return self.ui.config(b'remotefilelog', b'reponame')
@util.propertycache
def fallbackpath(self):
path = repo.ui.config(
b"remotefilelog",
b"fallbackpath",
repo.ui.config(b'paths', b'default'),
)
if not path:
raise error.Abort(
b"no remotefilelog server "
b"configured - is your .hg/hgrc trusted?"
)
return path
def maybesparsematch(self, *revs, **kwargs):
'''
A wrapper that allows the remotefilelog to invoke sparsematch() if
this is a sparse repository, or returns None if this is not a
sparse repository.
'''
if revs:
ret = sparse.matcher(repo, revs=revs)
else:
ret = sparse.matcher(repo)
if ret.always():
return None
return ret
def file(self, f):
if f[0] == b'/':
f = f[1:]
if self.shallowmatch(f):
return remotefilelog.remotefilelog(self.svfs, f, self)
else:
return super(shallowrepository, self).file(f)
def filectx(self, path, *args, **kwargs):
if self.shallowmatch(path):
return remotefilectx.remotefilectx(self, path, *args, **kwargs)
else:
return super(shallowrepository, self).filectx(
path, *args, **kwargs
)
@localrepo.unfilteredmethod
def commitctx(self, ctx, error=False, origctx=None):
"""Add a new revision to current repository.
Revision information is passed via the context argument.
"""
# some contexts already have manifest nodes, they don't need any
# prefetching (for example if we're just editing a commit message
# we can reuse manifest
if not ctx.manifestnode():
# prefetch files that will likely be compared
m1 = ctx.p1().manifest()
files = []
for f in ctx.modified() + ctx.added():
fparent1 = m1.get(f, nullid)
if fparent1 != nullid:
files.append((f, hex(fparent1)))
self.fileservice.prefetch(files)
return super(shallowrepository, self).commitctx(
ctx, error=error, origctx=origctx
)
def backgroundprefetch(
self, revs, base=None, repack=False, pats=None, opts=None
):
"""Runs prefetch in background with optional repack
"""
cmd = [procutil.hgexecutable(), b'-R', repo.origroot, b'prefetch']
if repack:
cmd.append(b'--repack')
if revs:
cmd += [b'-r', revs]
# We know this command will find a binary, so don't block
# on it starting.
kwargs = {}
if repo.ui.configbool(b'devel', b'remotefilelog.bg-wait'):
kwargs['record_wait'] = repo.ui.atexit
procutil.runbgcommand(
cmd, encoding.environ, ensurestart=False, **kwargs
)
def prefetch(self, revs, base=None, pats=None, opts=None):
"""Prefetches all the necessary file revisions for the given revs
Optionally runs repack in background
"""
with repo._lock(
repo.svfs,
b'prefetchlock',
True,
None,
None,
_(b'prefetching in %s') % repo.origroot,
):
self._prefetch(revs, base, pats, opts)
def _prefetch(self, revs, base=None, pats=None, opts=None):
fallbackpath = self.fallbackpath
if fallbackpath:
# If we know a rev is on the server, we should fetch the server
# version of those files, since our local file versions might
# become obsolete if the local commits are stripped.
localrevs = repo.revs(b'outgoing(%s)', fallbackpath)
if base is not None and base != nullrev:
serverbase = list(
repo.revs(
b'first(reverse(::%s) - %ld)', base, localrevs
)
)
if serverbase:
base = serverbase[0]
else:
localrevs = repo
mfl = repo.manifestlog
mfrevlog = mfl.getstorage(b'')
if base is not None:
mfdict = mfl[repo[base].manifestnode()].read()
skip = set(pycompat.iteritems(mfdict))
else:
skip = set()
# Copy the skip set to start large and avoid constant resizing,
# and since it's likely to be very similar to the prefetch set.
files = skip.copy()
serverfiles = skip.copy()
visited = set()
visited.add(nullrev)
revcount = len(revs)
progress = self.ui.makeprogress(_(b'prefetching'), total=revcount)
progress.update(0)
for rev in sorted(revs):
ctx = repo[rev]
if pats:
m = scmutil.match(ctx, pats, opts)
sparsematch = repo.maybesparsematch(rev)
mfnode = ctx.manifestnode()
mfrev = mfrevlog.rev(mfnode)
# Decompressing manifests is expensive.
# When possible, only read the deltas.
p1, p2 = mfrevlog.parentrevs(mfrev)
if p1 in visited and p2 in visited:
mfdict = mfl[mfnode].readfast()
else:
mfdict = mfl[mfnode].read()
diff = pycompat.iteritems(mfdict)
if pats:
diff = (pf for pf in diff if m(pf[0]))
if sparsematch:
diff = (pf for pf in diff if sparsematch(pf[0]))
if rev not in localrevs:
serverfiles.update(diff)
else:
files.update(diff)
visited.add(mfrev)
progress.increment()
files.difference_update(skip)
serverfiles.difference_update(skip)
progress.complete()
# Fetch files known to be on the server
if serverfiles:
results = [(path, hex(fnode)) for (path, fnode) in serverfiles]
repo.fileservice.prefetch(results, force=True)
# Fetch files that may or may not be on the server
if files:
results = [(path, hex(fnode)) for (path, fnode) in files]
repo.fileservice.prefetch(results)
def close(self):
super(shallowrepository, self).close()
self.connectionpool.close()
repo.__class__ = shallowrepository
repo.shallowmatch = match.always()
makeunionstores(repo)
repo.includepattern = repo.ui.configlist(
b"remotefilelog", b"includepattern", None
)
repo.excludepattern = repo.ui.configlist(
b"remotefilelog", b"excludepattern", None
)
if not util.safehasattr(repo, 'connectionpool'):
repo.connectionpool = connectionpool.connectionpool(repo)
if repo.includepattern or repo.excludepattern:
repo.shallowmatch = match.match(
repo.root, b'', None, repo.includepattern, repo.excludepattern
)