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localrepo: iteratively derive local repository type...
localrepo: iteratively derive local repository type This commit implements the dynamic local repository type derivation that was explained in the recent commit bfeab472e3c0 "localrepo: create new function for instantiating a local repo object." Instead of a static localrepository class/type which must be customized after construction, we now dynamically construct a type by building up base classes/types to represent specific repository interfaces. Conceptually, the end state is similar to what was happening when various extensions would monkeypatch the __class__ of newly-constructed repo instances. However, the approach is inverted. Instead of making the instance then customizing it, we do the customization up front by influencing the behavior of the type then we instantiate that custom type. This approach gives us much more flexibility. For example, we can use completely separate classes for implementing different aspects of the repository. For example, we could have one class representing revlog-based file storage and another representing non-revlog based file storage. When then choose which implementation to use based on the presence of repo requirements. A concern with this approach is that it creates a lot more types and complexity and that complexity adds overhead. Yes, it is true that this approach will result in more types being created. Yes, this is more complicated than traditional "instantiate a static type." However, I believe the alternatives to supporting alternate storage backends are just as complicated. (Before I arrived at this solution, I had patches storing factory functions on local repo instances for e.g. constructing a file storage instance. We ended up having a handful of these. And this was logically identical to assigning custom methods. Since we were logically changing the type of the instance, I figured it would be better to just use specialized types instead of introducing levels of abstraction at run-time.) On the performance front, I don't believe that having N base classes has any significant performance overhead compared to just a single base class. Intuition says that Python will need to iterate the base classes to find an attribute. However, CPython caches method lookups: as long as the __class__ or MRO isn't changing, method attribute lookup should be constant time after first access. And non-method attributes are stored in __dict__, of which there is only 1 per object, so the number of base classes for __dict__ is irrelevant. Anyway, this commit splits up the monolithic completelocalrepository interface into sub-interfaces: 1 for file storage and 1 representing everything else. We've taught ``makelocalrepository()`` to call a series of factory functions which will produce types implementing specific interfaces. It then calls type() to create a new type from the built-up list of base types. This commit should be considered a start and not the end state. I suspect we'll hit a number of problems as we start to implement alternate storage backends: * Passing custom arguments to __init__ and setting custom attributes on __dict__. * Customizing the set of interfaces that are needed. e.g. the "readonly" intent could translate to not requesting an interface providing methods related to writing. * More ergonomic way for extensions to insert themselves so their callbacks aren't unconditionally called. * Wanting to modify vfs instances, other arguments passed to __init__. That being said, this code is usable in its current state and I'm convinced future commits will demonstrate the value in this approach. Differential Revision: https://phab.mercurial-scm.org/D4642

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cvs.py
301 lines | 10.6 KiB | text/x-python | PythonLexer
# cvs.py: CVS conversion code inspired by hg-cvs-import and git-cvsimport
#
# Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others
#
# 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 errno
import os
import re
import socket
from mercurial.i18n import _
from mercurial import (
encoding,
error,
pycompat,
util,
)
from mercurial.utils import (
dateutil,
procutil,
)
from . import (
common,
cvsps,
)
stringio = util.stringio
checktool = common.checktool
commit = common.commit
converter_source = common.converter_source
makedatetimestamp = common.makedatetimestamp
NoRepo = common.NoRepo
class convert_cvs(converter_source):
def __init__(self, ui, repotype, path, revs=None):
super(convert_cvs, self).__init__(ui, repotype, path, revs=revs)
cvs = os.path.join(path, "CVS")
if not os.path.exists(cvs):
raise NoRepo(_("%s does not look like a CVS checkout") % path)
checktool('cvs')
self.changeset = None
self.files = {}
self.tags = {}
self.lastbranch = {}
self.socket = None
self.cvsroot = open(os.path.join(cvs, "Root"), 'rb').read()[:-1]
self.cvsrepo = open(os.path.join(cvs, "Repository"), 'rb').read()[:-1]
self.encoding = encoding.encoding
self._connect()
def _parse(self):
if self.changeset is not None:
return
self.changeset = {}
maxrev = 0
if self.revs:
if len(self.revs) > 1:
raise error.Abort(_('cvs source does not support specifying '
'multiple revs'))
# TODO: handle tags
try:
# patchset number?
maxrev = int(self.revs[0])
except ValueError:
raise error.Abort(_('revision %s is not a patchset number')
% self.revs[0])
d = pycompat.getcwd()
try:
os.chdir(self.path)
id = None
cache = 'update'
if not self.ui.configbool('convert', 'cvsps.cache'):
cache = None
db = cvsps.createlog(self.ui, cache=cache)
db = cvsps.createchangeset(self.ui, db,
fuzz=int(self.ui.config('convert', 'cvsps.fuzz')),
mergeto=self.ui.config('convert', 'cvsps.mergeto'),
mergefrom=self.ui.config('convert', 'cvsps.mergefrom'))
for cs in db:
if maxrev and cs.id > maxrev:
break
id = (b"%d" % cs.id)
cs.author = self.recode(cs.author)
self.lastbranch[cs.branch] = id
cs.comment = self.recode(cs.comment)
if self.ui.configbool('convert', 'localtimezone'):
cs.date = makedatetimestamp(cs.date[0])
date = dateutil.datestr(cs.date, '%Y-%m-%d %H:%M:%S %1%2')
self.tags.update(dict.fromkeys(cs.tags, id))
files = {}
for f in cs.entries:
files[f.file] = "%s%s" % ('.'.join([(b"%d" % x)
for x in f.revision]),
['', '(DEAD)'][f.dead])
# add current commit to set
c = commit(author=cs.author, date=date,
parents=[(b"%d" % p.id) for p in cs.parents],
desc=cs.comment, branch=cs.branch or '')
self.changeset[id] = c
self.files[id] = files
self.heads = self.lastbranch.values()
finally:
os.chdir(d)
def _connect(self):
root = self.cvsroot
conntype = None
user, host = None, None
cmd = ['cvs', 'server']
self.ui.status(_("connecting to %s\n") % root)
if root.startswith(":pserver:"):
root = root[9:]
m = re.match(r'(?:(.*?)(?::(.*?))?@)?([^:\/]*)(?::(\d*))?(.*)',
root)
if m:
conntype = "pserver"
user, passw, serv, port, root = m.groups()
if not user:
user = "anonymous"
if not port:
port = 2401
else:
port = int(port)
format0 = ":pserver:%s@%s:%s" % (user, serv, root)
format1 = ":pserver:%s@%s:%d%s" % (user, serv, port, root)
if not passw:
passw = "A"
cvspass = os.path.expanduser("~/.cvspass")
try:
pf = open(cvspass, 'rb')
for line in pf.read().splitlines():
part1, part2 = line.split(' ', 1)
# /1 :pserver:user@example.com:2401/cvsroot/foo
# Ah<Z
if part1 == '/1':
part1, part2 = part2.split(' ', 1)
format = format1
# :pserver:user@example.com:/cvsroot/foo Ah<Z
else:
format = format0
if part1 == format:
passw = part2
break
pf.close()
except IOError as inst:
if inst.errno != errno.ENOENT:
if not getattr(inst, 'filename', None):
inst.filename = cvspass
raise
sck = socket.socket()
sck.connect((serv, port))
sck.send("\n".join(["BEGIN AUTH REQUEST", root, user, passw,
"END AUTH REQUEST", ""]))
if sck.recv(128) != "I LOVE YOU\n":
raise error.Abort(_("CVS pserver authentication failed"))
self.writep = self.readp = sck.makefile('r+')
if not conntype and root.startswith(":local:"):
conntype = "local"
root = root[7:]
if not conntype:
# :ext:user@host/home/user/path/to/cvsroot
if root.startswith(":ext:"):
root = root[5:]
m = re.match(br'(?:([^@:/]+)@)?([^:/]+):?(.*)', root)
# Do not take Windows path "c:\foo\bar" for a connection strings
if os.path.isdir(root) or not m:
conntype = "local"
else:
conntype = "rsh"
user, host, root = m.group(1), m.group(2), m.group(3)
if conntype != "pserver":
if conntype == "rsh":
rsh = encoding.environ.get("CVS_RSH") or "ssh"
if user:
cmd = [rsh, '-l', user, host] + cmd
else:
cmd = [rsh, host] + cmd
# popen2 does not support argument lists under Windows
cmd = [procutil.shellquote(arg) for arg in cmd]
cmd = procutil.quotecommand(' '.join(cmd))
self.writep, self.readp = procutil.popen2(cmd)
self.realroot = root
self.writep.write("Root %s\n" % root)
self.writep.write("Valid-responses ok error Valid-requests Mode"
" M Mbinary E Checked-in Created Updated"
" Merged Removed\n")
self.writep.write("valid-requests\n")
self.writep.flush()
r = self.readp.readline()
if not r.startswith("Valid-requests"):
raise error.Abort(_('unexpected response from CVS server '
'(expected "Valid-requests", but got %r)')
% r)
if "UseUnchanged" in r:
self.writep.write("UseUnchanged\n")
self.writep.flush()
r = self.readp.readline()
def getheads(self):
self._parse()
return self.heads
def getfile(self, name, rev):
def chunkedread(fp, count):
# file-objects returned by socket.makefile() do not handle
# large read() requests very well.
chunksize = 65536
output = stringio()
while count > 0:
data = fp.read(min(count, chunksize))
if not data:
raise error.Abort(_("%d bytes missing from remote file")
% count)
count -= len(data)
output.write(data)
return output.getvalue()
self._parse()
if rev.endswith("(DEAD)"):
return None, None
args = ("-N -P -kk -r %s --" % rev).split()
args.append(self.cvsrepo + '/' + name)
for x in args:
self.writep.write("Argument %s\n" % x)
self.writep.write("Directory .\n%s\nco\n" % self.realroot)
self.writep.flush()
data = ""
mode = None
while True:
line = self.readp.readline()
if line.startswith("Created ") or line.startswith("Updated "):
self.readp.readline() # path
self.readp.readline() # entries
mode = self.readp.readline()[:-1]
count = int(self.readp.readline()[:-1])
data = chunkedread(self.readp, count)
elif line.startswith(" "):
data += line[1:]
elif line.startswith("M "):
pass
elif line.startswith("Mbinary "):
count = int(self.readp.readline()[:-1])
data = chunkedread(self.readp, count)
else:
if line == "ok\n":
if mode is None:
raise error.Abort(_('malformed response from CVS'))
return (data, "x" in mode and "x" or "")
elif line.startswith("E "):
self.ui.warn(_("cvs server: %s\n") % line[2:])
elif line.startswith("Remove"):
self.readp.readline()
else:
raise error.Abort(_("unknown CVS response: %s") % line)
def getchanges(self, rev, full):
if full:
raise error.Abort(_("convert from cvs does not support --full"))
self._parse()
return sorted(self.files[rev].iteritems()), {}, set()
def getcommit(self, rev):
self._parse()
return self.changeset[rev]
def gettags(self):
self._parse()
return self.tags
def getchangedfiles(self, rev, i):
self._parse()
return sorted(self.files[rev])