peer: introduce real peer classes
This change separates peer implementations from the repository implementation.
localpeer currently is a simple pass-through to localrepository, except for
legacy calls, which have already been removed from localpeer. This ensures that
the local client code only uses the most modern peer API when talking to local
repos.
Peers have a .local() method which returns either None or the underlying
localrepository (or descendant thereof). Repos have a .peer() method to return
a freshly constructed localpeer. The latter is used by hg.peer(), and also to
allow folks to pass either a peer or a repo to some generic helper methods.
We might want to get rid of .peer() eventually.
The only user of locallegacypeer is debugdiscovery, which uses it to pose as a
pre-setdiscovery client. But we decided to leave the old API defined in
locallegacypeer for clarity and maybe for other uses in the future.
It might be nice to actually define the peer API directly in peer.py as stub
methods. One problem there is, however, that localpeer implements
lock/addchangegroup, whereas the true remote peers implement unbundle.
It might be desireable to get rid of this distinction eventually.
# commandserver.py - communicate with Mercurial's API over a pipe
#
# Copyright Matt Mackall <mpm@selenic.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 i18n import _
import struct
import sys, os
import dispatch, encoding, util
logfile = None
def log(*args):
if not logfile:
return
for a in args:
logfile.write(str(a))
logfile.flush()
class channeledoutput(object):
"""
Write data from in_ to out in the following format:
data length (unsigned int),
data
"""
def __init__(self, in_, out, channel):
self.in_ = in_
self.out = out
self.channel = channel
def write(self, data):
if not data:
return
self.out.write(struct.pack('>cI', self.channel, len(data)))
self.out.write(data)
self.out.flush()
def __getattr__(self, attr):
if attr in ('isatty', 'fileno'):
raise AttributeError, attr
return getattr(self.in_, attr)
class channeledinput(object):
"""
Read data from in_.
Requests for input are written to out in the following format:
channel identifier - 'I' for plain input, 'L' line based (1 byte)
how many bytes to send at most (unsigned int),
The client replies with:
data length (unsigned int), 0 meaning EOF
data
"""
maxchunksize = 4 * 1024
def __init__(self, in_, out, channel):
self.in_ = in_
self.out = out
self.channel = channel
def read(self, size=-1):
if size < 0:
# if we need to consume all the clients input, ask for 4k chunks
# so the pipe doesn't fill up risking a deadlock
size = self.maxchunksize
s = self._read(size, self.channel)
buf = s
while s:
s = self._read(size, self.channel)
buf += s
return buf
else:
return self._read(size, self.channel)
def _read(self, size, channel):
if not size:
return ''
assert size > 0
# tell the client we need at most size bytes
self.out.write(struct.pack('>cI', channel, size))
self.out.flush()
length = self.in_.read(4)
length = struct.unpack('>I', length)[0]
if not length:
return ''
else:
return self.in_.read(length)
def readline(self, size=-1):
if size < 0:
size = self.maxchunksize
s = self._read(size, 'L')
buf = s
# keep asking for more until there's either no more or
# we got a full line
while s and s[-1] != '\n':
s = self._read(size, 'L')
buf += s
return buf
else:
return self._read(size, 'L')
def __iter__(self):
return self
def next(self):
l = self.readline()
if not l:
raise StopIteration
return l
def __getattr__(self, attr):
if attr in ('isatty', 'fileno'):
raise AttributeError, attr
return getattr(self.in_, attr)
class server(object):
"""
Listens for commands on stdin, runs them and writes the output on a channel
based stream to stdout.
"""
def __init__(self, ui, repo, mode):
self.cwd = os.getcwd()
logpath = ui.config("cmdserver", "log", None)
if logpath:
global logfile
if logpath == '-':
# write log on a special 'd'ebug channel
logfile = channeledoutput(sys.stdout, sys.stdout, 'd')
else:
logfile = open(logpath, 'a')
# the ui here is really the repo ui so take its baseui so we don't end
# up with its local configuration
self.ui = repo.baseui
self.repo = repo
self.repoui = repo.ui
if mode == 'pipe':
self.cerr = channeledoutput(sys.stderr, sys.stdout, 'e')
self.cout = channeledoutput(sys.stdout, sys.stdout, 'o')
self.cin = channeledinput(sys.stdin, sys.stdout, 'I')
self.cresult = channeledoutput(sys.stdout, sys.stdout, 'r')
self.client = sys.stdin
else:
raise util.Abort(_('unknown mode %s') % mode)
def _read(self, size):
if not size:
return ''
data = self.client.read(size)
# is the other end closed?
if not data:
raise EOFError
return data
def runcommand(self):
""" reads a list of \0 terminated arguments, executes
and writes the return code to the result channel """
length = struct.unpack('>I', self._read(4))[0]
if not length:
args = []
else:
args = self._read(length).split('\0')
# copy the uis so changes (e.g. --config or --verbose) don't
# persist between requests
copiedui = self.ui.copy()
self.repo.baseui = copiedui
self.repo.ui = self.repo.dirstate._ui = self.repoui.copy()
self.repo.invalidate()
self.repo.invalidatedirstate()
req = dispatch.request(args[:], copiedui, self.repo, self.cin,
self.cout, self.cerr)
ret = dispatch.dispatch(req) or 0 # might return None
# restore old cwd
if '--cwd' in args:
os.chdir(self.cwd)
self.cresult.write(struct.pack('>i', int(ret)))
def getencoding(self):
""" writes the current encoding to the result channel """
self.cresult.write(encoding.encoding)
def serveone(self):
cmd = self.client.readline()[:-1]
if cmd:
handler = self.capabilities.get(cmd)
if handler:
handler(self)
else:
# clients are expected to check what commands are supported by
# looking at the servers capabilities
raise util.Abort(_('unknown command %s') % cmd)
return cmd != ''
capabilities = {'runcommand' : runcommand,
'getencoding' : getencoding}
def serve(self):
hellomsg = 'capabilities: ' + ' '.join(self.capabilities.keys())
hellomsg += '\n'
hellomsg += 'encoding: ' + encoding.encoding
# write the hello msg in -one- chunk
self.cout.write(hellomsg)
try:
while self.serveone():
pass
except EOFError:
# we'll get here if the client disconnected while we were reading
# its request
return 1
return 0