obsolete: explicitly track folds inside the markers
We now record information to be able to recognize "fold" event from
obsolescence markers. To do so, we track the following pieces of information:
a) a fold ID. Unique to that fold (per successor),
b) the number of predecessors,
c) the index of the predecessor in that fold.
We will now be able to create an algorithm able to find "predecessorssets".
We now store this data in the generic "metadata" field of the markers.
Updating the format to have a more compact storage for this would be useful.
This way of tracking a fold through multiple markers could be applied to split
too. This would have two advantages:
1) We get a simpler format, since number of successors is limited to [0-1].
2) We can better deal with situations where only some of the split successors
are pushed to a remote repository.
We should look into the relevance of such a change before updating the on-disk
format.
note: unlike splits, folds do not have to deal with cases where only some of
the markers have been synchronized. As they all share the same successor
changesets, they are all relevant to the same nodes.
# wireprotosimplecache.py - Extension providing in-memory wire protocol cache
#
# Copyright 2018 Gregory Szorc <gregory.szorc@gmail.com>
#
# 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 (
extensions,
registrar,
repository,
util,
wireprotoserver,
wireprototypes,
wireprotov2server,
)
from mercurial.utils import (
interfaceutil,
stringutil,
)
CACHE = None
configtable = {}
configitem = registrar.configitem(configtable)
configitem('simplecache', 'cacheapi',
default=False)
configitem('simplecache', 'cacheobjects',
default=False)
configitem('simplecache', 'redirectsfile',
default=None)
# API handler that makes cached keys available.
def handlecacherequest(rctx, req, res, checkperm, urlparts):
if rctx.repo.ui.configbool('simplecache', 'cacheobjects'):
res.status = b'500 Internal Server Error'
res.setbodybytes(b'cacheobjects not supported for api server')
return
if not urlparts:
res.status = b'200 OK'
res.headers[b'Content-Type'] = b'text/plain'
res.setbodybytes(b'simple cache server')
return
key = b'/'.join(urlparts)
if key not in CACHE:
res.status = b'404 Not Found'
res.headers[b'Content-Type'] = b'text/plain'
res.setbodybytes(b'key not found in cache')
return
res.status = b'200 OK'
res.headers[b'Content-Type'] = b'application/mercurial-cbor'
res.setbodybytes(CACHE[key])
def cachedescriptor(req, repo):
return {}
wireprotoserver.API_HANDLERS[b'simplecache'] = {
'config': (b'simplecache', b'cacheapi'),
'handler': handlecacherequest,
'apidescriptor': cachedescriptor,
}
@interfaceutil.implementer(repository.iwireprotocolcommandcacher)
class memorycacher(object):
def __init__(self, ui, command, encodefn, redirecttargets, redirecthashes,
req):
self.ui = ui
self.encodefn = encodefn
self.redirecttargets = redirecttargets
self.redirecthashes = redirecthashes
self.req = req
self.key = None
self.cacheobjects = ui.configbool('simplecache', 'cacheobjects')
self.cacheapi = ui.configbool('simplecache', 'cacheapi')
self.buffered = []
ui.log('simplecache', 'cacher constructed for %s\n', command)
def __enter__(self):
return self
def __exit__(self, exctype, excvalue, exctb):
if exctype:
self.ui.log('simplecache', 'cacher exiting due to error\n')
def adjustcachekeystate(self, state):
# Needed in order to make tests deterministic. Don't copy this
# pattern for production caches!
del state[b'repo']
def setcachekey(self, key):
self.key = key
return True
def lookup(self):
if self.key not in CACHE:
self.ui.log('simplecache', 'cache miss for %s\n', self.key)
return None
entry = CACHE[self.key]
self.ui.log('simplecache', 'cache hit for %s\n', self.key)
redirectable = True
if not self.cacheapi:
redirectable = False
elif not self.redirecttargets:
redirectable = False
else:
clienttargets = set(self.redirecttargets)
ourtargets = set(t[b'name'] for t in loadredirecttargets(self.ui))
# We only ever redirect to a single target (for now). So we don't
# need to store which target matched.
if not clienttargets & ourtargets:
redirectable = False
if redirectable:
paths = self.req.dispatchparts[:-3]
paths.append(b'simplecache')
paths.append(self.key)
url = b'%s/%s' % (self.req.advertisedbaseurl, b'/'.join(paths))
#url = b'http://example.com/%s' % self.key
self.ui.log('simplecache', 'sending content redirect for %s to '
'%s\n', self.key, url)
response = wireprototypes.alternatelocationresponse(
url=url,
mediatype=b'application/mercurial-cbor')
return {'objs': [response]}
if self.cacheobjects:
return {
'objs': entry,
}
else:
return {
'objs': [wireprototypes.encodedresponse(entry)],
}
def onobject(self, obj):
if self.cacheobjects:
self.buffered.append(obj)
else:
self.buffered.extend(self.encodefn(obj))
yield obj
def onfinished(self):
self.ui.log('simplecache', 'storing cache entry for %s\n', self.key)
if self.cacheobjects:
CACHE[self.key] = self.buffered
else:
CACHE[self.key] = b''.join(self.buffered)
return []
def makeresponsecacher(orig, repo, proto, command, args, objencoderfn,
redirecttargets, redirecthashes):
return memorycacher(repo.ui, command, objencoderfn, redirecttargets,
redirecthashes, proto._req)
def loadredirecttargets(ui):
path = ui.config('simplecache', 'redirectsfile')
if not path:
return []
with open(path, 'rb') as fh:
s = fh.read()
return stringutil.evalpythonliteral(s)
def getadvertisedredirecttargets(orig, repo, proto):
return loadredirecttargets(repo.ui)
def extsetup(ui):
global CACHE
CACHE = util.lrucachedict(10000)
extensions.wrapfunction(wireprotov2server, 'makeresponsecacher',
makeresponsecacher)
extensions.wrapfunction(wireprotov2server, 'getadvertisedredirecttargets',
getadvertisedredirecttargets)