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
from __future__ import absolute_import
import threading
from mercurial.node import hex, nullid
from mercurial.pycompat import getattr
from mercurial import (
mdiff,
pycompat,
revlog,
)
from . import (
basestore,
constants,
shallowutil,
)
class ChainIndicies(object):
"""A static class for easy reference to the delta chain indicies.
"""
# The filename of this revision delta
NAME = 0
# The mercurial file node for this revision delta
NODE = 1
# The filename of the delta base's revision. This is useful when delta
# between different files (like in the case of a move or copy, we can delta
# against the original file content).
BASENAME = 2
# The mercurial file node for the delta base revision. This is the nullid if
# this delta is a full text.
BASENODE = 3
# The actual delta or full text data.
DATA = 4
class unioncontentstore(basestore.baseunionstore):
def __init__(self, *args, **kwargs):
super(unioncontentstore, self).__init__(*args, **kwargs)
self.stores = args
self.writestore = kwargs.get('writestore')
# If allowincomplete==True then the union store can return partial
# delta chains, otherwise it will throw a KeyError if a full
# deltachain can't be found.
self.allowincomplete = kwargs.get('allowincomplete', False)
def get(self, name, node):
"""Fetches the full text revision contents of the given name+node pair.
If the full text doesn't exist, throws a KeyError.
Under the hood, this uses getdeltachain() across all the stores to build
up a full chain to produce the full text.
"""
chain = self.getdeltachain(name, node)
if chain[-1][ChainIndicies.BASENODE] != nullid:
# If we didn't receive a full chain, throw
raise KeyError((name, hex(node)))
# The last entry in the chain is a full text, so we start our delta
# applies with that.
fulltext = chain.pop()[ChainIndicies.DATA]
text = fulltext
while chain:
delta = chain.pop()[ChainIndicies.DATA]
text = mdiff.patches(text, [delta])
return text
@basestore.baseunionstore.retriable
def getdelta(self, name, node):
"""Return the single delta entry for the given name/node pair.
"""
for store in self.stores:
try:
return store.getdelta(name, node)
except KeyError:
pass
raise KeyError((name, hex(node)))
def getdeltachain(self, name, node):
"""Returns the deltachain for the given name/node pair.
Returns an ordered list of:
[(name, node, deltabasename, deltabasenode, deltacontent),...]
where the chain is terminated by a full text entry with a nullid
deltabasenode.
"""
chain = self._getpartialchain(name, node)
while chain[-1][ChainIndicies.BASENODE] != nullid:
x, x, deltabasename, deltabasenode, x = chain[-1]
try:
morechain = self._getpartialchain(deltabasename, deltabasenode)
chain.extend(morechain)
except KeyError:
# If we allow incomplete chains, don't throw.
if not self.allowincomplete:
raise
break
return chain
@basestore.baseunionstore.retriable
def getmeta(self, name, node):
"""Returns the metadata dict for given node."""
for store in self.stores:
try:
return store.getmeta(name, node)
except KeyError:
pass
raise KeyError((name, hex(node)))
def getmetrics(self):
metrics = [s.getmetrics() for s in self.stores]
return shallowutil.sumdicts(*metrics)
@basestore.baseunionstore.retriable
def _getpartialchain(self, name, node):
"""Returns a partial delta chain for the given name/node pair.
A partial chain is a chain that may not be terminated in a full-text.
"""
for store in self.stores:
try:
return store.getdeltachain(name, node)
except KeyError:
pass
raise KeyError((name, hex(node)))
def add(self, name, node, data):
raise RuntimeError(
b"cannot add content only to remotefilelog contentstore"
)
def getmissing(self, keys):
missing = keys
for store in self.stores:
if missing:
missing = store.getmissing(missing)
return missing
def addremotefilelognode(self, name, node, data):
if self.writestore:
self.writestore.addremotefilelognode(name, node, data)
else:
raise RuntimeError(b"no writable store configured")
def markledger(self, ledger, options=None):
for store in self.stores:
store.markledger(ledger, options)
class remotefilelogcontentstore(basestore.basestore):
def __init__(self, *args, **kwargs):
super(remotefilelogcontentstore, self).__init__(*args, **kwargs)
self._threaddata = threading.local()
def get(self, name, node):
# return raw revision text
data = self._getdata(name, node)
offset, size, flags = shallowutil.parsesizeflags(data)
content = data[offset : offset + size]
ancestormap = shallowutil.ancestormap(data)
p1, p2, linknode, copyfrom = ancestormap[node]
copyrev = None
if copyfrom:
copyrev = hex(p1)
self._updatemetacache(node, size, flags)
# lfs tracks renames in its own metadata, remove hg copy metadata,
# because copy metadata will be re-added by lfs flag processor.
if flags & revlog.REVIDX_EXTSTORED:
copyrev = copyfrom = None
revision = shallowutil.createrevlogtext(content, copyfrom, copyrev)
return revision
def getdelta(self, name, node):
# Since remotefilelog content stores only contain full texts, just
# return that.
revision = self.get(name, node)
return revision, name, nullid, self.getmeta(name, node)
def getdeltachain(self, name, node):
# Since remotefilelog content stores just contain full texts, we return
# a fake delta chain that just consists of a single full text revision.
# The nullid in the deltabasenode slot indicates that the revision is a
# fulltext.
revision = self.get(name, node)
return [(name, node, None, nullid, revision)]
def getmeta(self, name, node):
self._sanitizemetacache()
if node != self._threaddata.metacache[0]:
data = self._getdata(name, node)
offset, size, flags = shallowutil.parsesizeflags(data)
self._updatemetacache(node, size, flags)
return self._threaddata.metacache[1]
def add(self, name, node, data):
raise RuntimeError(
b"cannot add content only to remotefilelog contentstore"
)
def _sanitizemetacache(self):
metacache = getattr(self._threaddata, 'metacache', None)
if metacache is None:
self._threaddata.metacache = (None, None) # (node, meta)
def _updatemetacache(self, node, size, flags):
self._sanitizemetacache()
if node == self._threaddata.metacache[0]:
return
meta = {constants.METAKEYFLAG: flags, constants.METAKEYSIZE: size}
self._threaddata.metacache = (node, meta)
class remotecontentstore(object):
def __init__(self, ui, fileservice, shared):
self._fileservice = fileservice
# type(shared) is usually remotefilelogcontentstore
self._shared = shared
def get(self, name, node):
self._fileservice.prefetch(
[(name, hex(node))], force=True, fetchdata=True
)
return self._shared.get(name, node)
def getdelta(self, name, node):
revision = self.get(name, node)
return revision, name, nullid, self._shared.getmeta(name, node)
def getdeltachain(self, name, node):
# Since our remote content stores just contain full texts, we return a
# fake delta chain that just consists of a single full text revision.
# The nullid in the deltabasenode slot indicates that the revision is a
# fulltext.
revision = self.get(name, node)
return [(name, node, None, nullid, revision)]
def getmeta(self, name, node):
self._fileservice.prefetch(
[(name, hex(node))], force=True, fetchdata=True
)
return self._shared.getmeta(name, node)
def add(self, name, node, data):
raise RuntimeError(b"cannot add to a remote store")
def getmissing(self, keys):
return keys
def markledger(self, ledger, options=None):
pass
class manifestrevlogstore(object):
def __init__(self, repo):
self._store = repo.store
self._svfs = repo.svfs
self._revlogs = dict()
self._cl = revlog.revlog(self._svfs, b'00changelog.i')
self._repackstartlinkrev = 0
def get(self, name, node):
return self._revlog(name).rawdata(node)
def getdelta(self, name, node):
revision = self.get(name, node)
return revision, name, nullid, self.getmeta(name, node)
def getdeltachain(self, name, node):
revision = self.get(name, node)
return [(name, node, None, nullid, revision)]
def getmeta(self, name, node):
rl = self._revlog(name)
rev = rl.rev(node)
return {
constants.METAKEYFLAG: rl.flags(rev),
constants.METAKEYSIZE: rl.rawsize(rev),
}
def getancestors(self, name, node, known=None):
if known is None:
known = set()
if node in known:
return []
rl = self._revlog(name)
ancestors = {}
missing = {node}
for ancrev in rl.ancestors([rl.rev(node)], inclusive=True):
ancnode = rl.node(ancrev)
missing.discard(ancnode)
p1, p2 = rl.parents(ancnode)
if p1 != nullid and p1 not in known:
missing.add(p1)
if p2 != nullid and p2 not in known:
missing.add(p2)
linknode = self._cl.node(rl.linkrev(ancrev))
ancestors[rl.node(ancrev)] = (p1, p2, linknode, b'')
if not missing:
break
return ancestors
def getnodeinfo(self, name, node):
cl = self._cl
rl = self._revlog(name)
parents = rl.parents(node)
linkrev = rl.linkrev(rl.rev(node))
return (parents[0], parents[1], cl.node(linkrev), None)
def add(self, *args):
raise RuntimeError(b"cannot add to a revlog store")
def _revlog(self, name):
rl = self._revlogs.get(name)
if rl is None:
revlogname = b'00manifesttree.i'
if name != b'':
revlogname = b'meta/%s/00manifest.i' % name
rl = revlog.revlog(self._svfs, revlogname)
self._revlogs[name] = rl
return rl
def getmissing(self, keys):
missing = []
for name, node in keys:
mfrevlog = self._revlog(name)
if node not in mfrevlog.nodemap:
missing.append((name, node))
return missing
def setrepacklinkrevrange(self, startrev, endrev):
self._repackstartlinkrev = startrev
self._repackendlinkrev = endrev
def markledger(self, ledger, options=None):
if options and options.get(constants.OPTION_PACKSONLY):
return
treename = b''
rl = revlog.revlog(self._svfs, b'00manifesttree.i')
startlinkrev = self._repackstartlinkrev
endlinkrev = self._repackendlinkrev
for rev in pycompat.xrange(len(rl) - 1, -1, -1):
linkrev = rl.linkrev(rev)
if linkrev < startlinkrev:
break
if linkrev > endlinkrev:
continue
node = rl.node(rev)
ledger.markdataentry(self, treename, node)
ledger.markhistoryentry(self, treename, node)
for path, encoded, size in self._store.datafiles():
if path[:5] != b'meta/' or path[-2:] != b'.i':
continue
treename = path[5 : -len(b'/00manifest.i')]
rl = revlog.revlog(self._svfs, path)
for rev in pycompat.xrange(len(rl) - 1, -1, -1):
linkrev = rl.linkrev(rev)
if linkrev < startlinkrev:
break
if linkrev > endlinkrev:
continue
node = rl.node(rev)
ledger.markdataentry(self, treename, node)
ledger.markhistoryentry(self, treename, node)
def cleanup(self, ledger):
pass