wireproto: drop the _decompress method in favor a new call type

We already have multiple call function for multiple return type. The
`_decompress` function is only used for http and seems like a layer violation.
We drop it in favor of a new call type dedicated to "stream that may be useful to
compress".

mercurial/httppeer.py

@@ -1,249 +1,247
 # httppeer.py - HTTP repository proxy classes for mercurial
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from node import nullid
 from i18n import _
 import changegroup, statichttprepo, error, httpconnection, url, util, wireproto
 import os, urllib, urllib2, zlib, httplib
 import errno, socket
 
 def zgenerator(f):
     zd = zlib.decompressobj()
     try:
         for chunk in util.filechunkiter(f):
             while chunk:
                 yield zd.decompress(chunk, 2**18)
                 chunk = zd.unconsumed_tail
     except httplib.HTTPException:
         raise IOError(None, _('connection ended unexpectedly'))
     yield zd.flush()
 
 class httppeer(wireproto.wirepeer):
     def __init__(self, ui, path):
         self.path = path
         self.caps = None
         self.handler = None
         self.urlopener = None
         u = util.url(path)
         if u.query or u.fragment:
             raise util.Abort(_('unsupported URL component: "%s"') %
                              (u.query or u.fragment))
 
         # urllib cannot handle URLs with embedded user or passwd
         self._url, authinfo = u.authinfo()
 
         self.ui = ui
         self.ui.debug('using %s\n' % self._url)
 
         self.urlopener = url.opener(ui, authinfo)
 
     def __del__(self):
         if self.urlopener:
             for h in self.urlopener.handlers:
                 h.close()
                 getattr(h, "close_all", lambda : None)()
 
     def url(self):
         return self.path
 
     # look up capabilities only when needed
 
     def _fetchcaps(self):
         self.caps = set(self._call('capabilities').split())
 
     def _capabilities(self):
         if self.caps is None:
             try:
                 self._fetchcaps()
             except error.RepoError:
                 self.caps = set()
             self.ui.debug('capabilities: %s\n' %
                           (' '.join(self.caps or ['none'])))
         return self.caps
 
     def lock(self):
         raise util.Abort(_('operation not supported over http'))
 
     def _callstream(self, cmd, **args):
         if cmd == 'pushkey':
             args['data'] = ''
         data = args.pop('data', None)
         size = 0
         if util.safehasattr(data, 'length'):
             size = data.length
         elif data is not None:
             size = len(data)
         headers = args.pop('headers', {})
         if data is not None and 'Content-Type' not in headers:
             headers['Content-Type'] = 'application/mercurial-0.1'
 
 
         if size and self.ui.configbool('ui', 'usehttp2', False):
             headers['Expect'] = '100-Continue'
             headers['X-HgHttp2'] = '1'
 
         self.ui.debug("sending %s command\n" % cmd)
         q = [('cmd', cmd)]
         headersize = 0
         if len(args) > 0:
             httpheader = self.capable('httpheader')
             if httpheader:
                 headersize = int(httpheader.split(',')[0])
         if headersize > 0:
             # The headers can typically carry more data than the URL.
             encargs = urllib.urlencode(sorted(args.items()))
             headerfmt = 'X-HgArg-%s'
             contentlen = headersize - len(headerfmt % '000' + ': \r\n')
             headernum = 0
             for i in xrange(0, len(encargs), contentlen):
                 headernum += 1
                 header = headerfmt % str(headernum)
                 headers[header] = encargs[i:i + contentlen]
             varyheaders = [headerfmt % str(h) for h in range(1, headernum + 1)]
             headers['Vary'] = ','.join(varyheaders)
         else:
             q += sorted(args.items())
         qs = '?%s' % urllib.urlencode(q)
         cu = "%s%s" % (self._url, qs)
         req = urllib2.Request(cu, data, headers)
         if data is not None:
             self.ui.debug("sending %s bytes\n" % size)
             req.add_unredirected_header('Content-Length', '%d' % size)
         try:
             resp = self.urlopener.open(req)
         except urllib2.HTTPError, inst:
             if inst.code == 401:
                 raise util.Abort(_('authorization failed'))
             raise
         except httplib.HTTPException, inst:
             self.ui.debug('http error while sending %s command\n' % cmd)
             self.ui.traceback()
             raise IOError(None, inst)
         except IndexError:
             # this only happens with Python 2.3, later versions raise URLError
             raise util.Abort(_('http error, possibly caused by proxy setting'))
         # record the url we got redirected to
         resp_url = resp.geturl()
         if resp_url.endswith(qs):
             resp_url = resp_url[:-len(qs)]
         if self._url.rstrip('/') != resp_url.rstrip('/'):
             if not self.ui.quiet:
                 self.ui.warn(_('real URL is %s\n') % resp_url)
         self._url = resp_url
         try:
             proto = resp.getheader('content-type')
         except AttributeError:
             proto = resp.headers.get('content-type', '')
 
         safeurl = util.hidepassword(self._url)
         if proto.startswith('application/hg-error'):
             raise error.OutOfBandError(resp.read())
         # accept old "text/plain" and "application/hg-changegroup" for now
         if not (proto.startswith('application/mercurial-') or
                 (proto.startswith('text/plain')
                  and not resp.headers.get('content-length')) or
                 proto.startswith('application/hg-changegroup')):
             self.ui.debug("requested URL: '%s'\n" % util.hidepassword(cu))
             raise error.RepoError(
                 _("'%s' does not appear to be an hg repository:\n"
                   "---%%<--- (%s)\n%s\n---%%<---\n")
                 % (safeurl, proto or 'no content-type', resp.read(1024)))
 
         if proto.startswith('application/mercurial-'):
             try:
                 version = proto.split('-', 1)[1]
                 version_info = tuple([int(n) for n in version.split('.')])
             except ValueError:
                 raise error.RepoError(_("'%s' sent a broken Content-Type "
                                         "header (%s)") % (safeurl, proto))
             if version_info > (0, 1):
                 raise error.RepoError(_("'%s' uses newer protocol %s") %
                                       (safeurl, version))
 
         return resp
 
     def _call(self, cmd, **args):
         fp = self._callstream(cmd, **args)
         try:
             return fp.read()
         finally:
             # if using keepalive, allow connection to be reused
             fp.close()
 
     def _callpush(self, cmd, cg, **args):
         # have to stream bundle to a temp file because we do not have
         # http 1.1 chunked transfer.
 
         types = self.capable('unbundle')
         try:
             types = types.split(',')
         except AttributeError:
             # servers older than d1b16a746db6 will send 'unbundle' as a
             # boolean capability. They only support headerless/uncompressed
             # bundles.
             types = [""]
         for x in types:
             if x in changegroup.bundletypes:
                 type = x
                 break
 
         tempname = changegroup.writebundle(cg, None, type)
         fp = httpconnection.httpsendfile(self.ui, tempname, "rb")
         headers = {'Content-Type': 'application/mercurial-0.1'}
 
         try:
             try:
                 r = self._call(cmd, data=fp, headers=headers, **args)
                 vals = r.split('\n', 1)
                 if len(vals) < 2:
                     raise error.ResponseError(_("unexpected response:"), r)
                 return vals
             except socket.error, err:
                 if err.args[0] in (errno.ECONNRESET, errno.EPIPE):
                     raise util.Abort(_('push failed: %s') % err.args[1])
                 raise util.Abort(err.args[1])
         finally:
             fp.close()
             os.unlink(tempname)
 
-    def _abort(self, exception):
-        raise exception
-
-    def _decompress(self, stream):
+    def _callcompressable(self, cmd, **args):
+        stream =  self._callstream(cmd, **args)
         return util.chunkbuffer(zgenerator(stream))
 
 class httpspeer(httppeer):
     def __init__(self, ui, path):
         if not url.has_https:
             raise util.Abort(_('Python support for SSL and HTTPS '
                                'is not installed'))
         httppeer.__init__(self, ui, path)
 
 def instance(ui, path, create):
     if create:
         raise util.Abort(_('cannot create new http repository'))
     try:
         if path.startswith('https:'):
             inst = httpspeer(ui, path)
         else:
             inst = httppeer(ui, path)
         try:
             # Try to do useful work when checking compatibility.
             # Usually saves a roundtrip since we want the caps anyway.
             inst._fetchcaps()
         except error.RepoError:
             # No luck, try older compatibility check.
             inst.between([(nullid, nullid)])
         return inst
     except error.RepoError, httpexception:
         try:
             r = statichttprepo.instance(ui, "static-" + path, create)
             ui.note('(falling back to static-http)\n')
             return r
         except error.RepoError:
             raise httpexception # use the original http RepoError instead

mercurial/sshpeer.py

@@ -1,242 +1,243
 # sshpeer.py - ssh repository proxy class for mercurial
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 import re
 from i18n import _
 import util, error, wireproto
 
 class remotelock(object):
     def __init__(self, repo):
         self.repo = repo
     def release(self):
         self.repo.unlock()
         self.repo = None
     def __del__(self):
         if self.repo:
             self.release()
 
 def _serverquote(s):
     '''quote a string for the remote shell ... which we assume is sh'''
     if re.match('[a-zA-Z0-9@%_+=:,./-]*$', s):
         return s
     return "'%s'" % s.replace("'", "'\\''")
 
 class sshpeer(wireproto.wirepeer):
     def __init__(self, ui, path, create=False):
         self._url = path
         self.ui = ui
         self.pipeo = self.pipei = self.pipee = None
 
         u = util.url(path, parsequery=False, parsefragment=False)
         if u.scheme != 'ssh' or not u.host or u.path is None:
             self._abort(error.RepoError(_("couldn't parse location %s") % path))
 
         self.user = u.user
         if u.passwd is not None:
             self._abort(error.RepoError(_("password in URL not supported")))
         self.host = u.host
         self.port = u.port
         self.path = u.path or "."
 
         sshcmd = self.ui.config("ui", "ssh", "ssh")
         remotecmd = self.ui.config("ui", "remotecmd", "hg")
 
         args = util.sshargs(sshcmd, self.host, self.user, self.port)
 
         if create:
             cmd = '%s %s %s' % (sshcmd, args,
                 util.shellquote("%s init %s" %
                     (_serverquote(remotecmd), _serverquote(self.path))))
             ui.debug('running %s\n' % cmd)
             res = util.system(cmd)
             if res != 0:
                 self._abort(error.RepoError(_("could not create remote repo")))
 
         self._validaterepo(sshcmd, args, remotecmd)
 
     def url(self):
         return self._url
 
     def _validaterepo(self, sshcmd, args, remotecmd):
         # cleanup up previous run
         self.cleanup()
 
         cmd = '%s %s %s' % (sshcmd, args,
             util.shellquote("%s -R %s serve --stdio" %
                 (_serverquote(remotecmd), _serverquote(self.path))))
         self.ui.debug('running %s\n' % cmd)
         cmd = util.quotecommand(cmd)
 
         # while self.subprocess isn't used, having it allows the subprocess to
         # to clean up correctly later
         self.pipeo, self.pipei, self.pipee, self.subprocess = util.popen4(cmd)
 
         # skip any noise generated by remote shell
         self._callstream("hello")
         r = self._callstream("between", pairs=("%s-%s" % ("0"*40, "0"*40)))
         lines = ["", "dummy"]
         max_noise = 500
         while lines[-1] and max_noise:
             l = r.readline()
             self.readerr()
             if lines[-1] == "1\n" and l == "\n":
                 break
             if l:
                 self.ui.debug("remote: ", l)
             lines.append(l)
             max_noise -= 1
         else:
             self._abort(error.RepoError(_('no suitable response from '
                                           'remote hg')))
 
         self._caps = set()
         for l in reversed(lines):
             if l.startswith("capabilities:"):
                 self._caps.update(l[:-1].split(":")[1].split())
                 break
 
     def _capabilities(self):
         return self._caps
 
     def readerr(self):
         while True:
             size = util.fstat(self.pipee).st_size
             if size == 0:
                 break
             s = self.pipee.read(size)
             if not s:
                 break
             for l in s.splitlines():
                 self.ui.status(_("remote: "), l, '\n')
 
     def _abort(self, exception):
         self.cleanup()
         raise exception
 
     def cleanup(self):
         if self.pipeo is None:
             return
         self.pipeo.close()
         self.pipei.close()
         try:
             # read the error descriptor until EOF
             for l in self.pipee:
                 self.ui.status(_("remote: "), l)
         except (IOError, ValueError):
             pass
         self.pipee.close()
 
     __del__ = cleanup
 
     def _callstream(self, cmd, **args):
         self.ui.debug("sending %s command\n" % cmd)
         self.pipeo.write("%s\n" % cmd)
         _func, names = wireproto.commands[cmd]
         keys = names.split()
         wireargs = {}
         for k in keys:
             if k == '*':
                 wireargs['*'] = args
                 break
             else:
                 wireargs[k] = args[k]
                 del args[k]
         for k, v in sorted(wireargs.iteritems()):
             self.pipeo.write("%s %d\n" % (k, len(v)))
             if isinstance(v, dict):
                 for dk, dv in v.iteritems():
                     self.pipeo.write("%s %d\n" % (dk, len(dv)))
                     self.pipeo.write(dv)
             else:
                 self.pipeo.write(v)
         self.pipeo.flush()
 
         return self.pipei
 
+    def _callcompressable(self, cmd, **args):
+        return self._callstream(cmd, **args)
+
     def _call(self, cmd, **args):
         self._callstream(cmd, **args)
         return self._recv()
 
     def _callpush(self, cmd, fp, **args):
         r = self._call(cmd, **args)
         if r:
             return '', r
         while True:
             d = fp.read(4096)
             if not d:
                 break
             self._send(d)
         self._send("", flush=True)
         r = self._recv()
         if r:
             return '', r
         return self._recv(), ''
 
-    def _decompress(self, stream):
-        return stream
 
     def _recv(self):
         l = self.pipei.readline()
         if l == '\n':
             err = []
             while True:
                 line = self.pipee.readline()
                 if line == '-\n':
                     break
                 err.extend([line])
             if len(err) > 0:
                 # strip the trailing newline added to the last line server-side
                 err[-1] = err[-1][:-1]
             self._abort(error.OutOfBandError(*err))
         self.readerr()
         try:
             l = int(l)
         except ValueError:
             self._abort(error.ResponseError(_("unexpected response:"), l))
         return self.pipei.read(l)
 
     def _send(self, data, flush=False):
         self.pipeo.write("%d\n" % len(data))
         if data:
             self.pipeo.write(data)
         if flush:
             self.pipeo.flush()
         self.readerr()
 
     def lock(self):
         self._call("lock")
         return remotelock(self)
 
     def unlock(self):
         self._call("unlock")
 
     def addchangegroup(self, cg, source, url, lock=None):
         '''Send a changegroup to the remote server.  Return an integer
         similar to unbundle(). DEPRECATED, since it requires locking the
         remote.'''
         d = self._call("addchangegroup")
         if d:
             self._abort(error.RepoError(_("push refused: %s") % d))
         while True:
             d = cg.read(4096)
             if not d:
                 break
             self.pipeo.write(d)
             self.readerr()
 
         self.pipeo.flush()
 
         self.readerr()
         r = self._recv()
         if not r:
             return 1
         try:
             return int(r)
         except ValueError:
             self._abort(error.ResponseError(_("unexpected response:"), r))
 
 instance = sshpeer

mercurial/wireproto.py

@@ -1,784 +1,791
 # wireproto.py - generic wire protocol support functions
 #
 # Copyright 2005-2010 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 import urllib, tempfile, os, sys
 from i18n import _
 from node import bin, hex
 import changegroup as changegroupmod
 import peer, error, encoding, util, store
 
 
 class abstractserverproto(object):
     """abstract class that summarizes the protocol API
 
     Used as reference and documentation.
     """
 
     def getargs(self, args):
         """return the value for arguments in <args>
 
         returns a list of values (same order as <args>)"""
         raise NotImplementedError()
 
     def getfile(self, fp):
         """write the whole content of a file into a file like object
 
         The file is in the form::
 
             (<chunk-size>\n<chunk>)+0\n
 
         chunk size is the ascii version of the int.
         """
         raise NotImplementedError()
 
     def redirect(self):
         """may setup interception for stdout and stderr
 
         See also the `restore` method."""
         raise NotImplementedError()
 
     # If the `redirect` function does install interception, the `restore`
     # function MUST be defined. If interception is not used, this function
     # MUST NOT be defined.
     #
     # left commented here on purpose
     #
     #def restore(self):
     #    """reinstall previous stdout and stderr and return intercepted stdout
     #    """
     #    raise NotImplementedError()
 
     def groupchunks(self, cg):
         """return 4096 chunks from a changegroup object
 
         Some protocols may have compressed the contents."""
         raise NotImplementedError()
 
 # abstract batching support
 
 class future(object):
     '''placeholder for a value to be set later'''
     def set(self, value):
         if util.safehasattr(self, 'value'):
             raise error.RepoError("future is already set")
         self.value = value
 
 class batcher(object):
     '''base class for batches of commands submittable in a single request
 
     All methods invoked on instances of this class are simply queued and
     return a a future for the result. Once you call submit(), all the queued
     calls are performed and the results set in their respective futures.
     '''
     def __init__(self):
         self.calls = []
     def __getattr__(self, name):
         def call(*args, **opts):
             resref = future()
             self.calls.append((name, args, opts, resref,))
             return resref
         return call
     def submit(self):
         pass
 
 class localbatch(batcher):
     '''performs the queued calls directly'''
     def __init__(self, local):
         batcher.__init__(self)
         self.local = local
     def submit(self):
         for name, args, opts, resref in self.calls:
             resref.set(getattr(self.local, name)(*args, **opts))
 
 class remotebatch(batcher):
     '''batches the queued calls; uses as few roundtrips as possible'''
     def __init__(self, remote):
         '''remote must support _submitbatch(encbatch) and
         _submitone(op, encargs)'''
         batcher.__init__(self)
         self.remote = remote
     def submit(self):
         req, rsp = [], []
         for name, args, opts, resref in self.calls:
             mtd = getattr(self.remote, name)
             batchablefn = getattr(mtd, 'batchable', None)
             if batchablefn is not None:
                 batchable = batchablefn(mtd.im_self, *args, **opts)
                 encargsorres, encresref = batchable.next()
                 if encresref:
                     req.append((name, encargsorres,))
                     rsp.append((batchable, encresref, resref,))
                 else:
                     resref.set(encargsorres)
             else:
                 if req:
                     self._submitreq(req, rsp)
                     req, rsp = [], []
                 resref.set(mtd(*args, **opts))
         if req:
             self._submitreq(req, rsp)
     def _submitreq(self, req, rsp):
         encresults = self.remote._submitbatch(req)
         for encres, r in zip(encresults, rsp):
             batchable, encresref, resref = r
             encresref.set(encres)
             resref.set(batchable.next())
 
 def batchable(f):
     '''annotation for batchable methods
 
     Such methods must implement a coroutine as follows:
 
     @batchable
     def sample(self, one, two=None):
         # Handle locally computable results first:
         if not one:
             yield "a local result", None
         # Build list of encoded arguments suitable for your wire protocol:
         encargs = [('one', encode(one),), ('two', encode(two),)]
         # Create future for injection of encoded result:
         encresref = future()
         # Return encoded arguments and future:
         yield encargs, encresref
         # Assuming the future to be filled with the result from the batched
         # request now. Decode it:
         yield decode(encresref.value)
 
     The decorator returns a function which wraps this coroutine as a plain
     method, but adds the original method as an attribute called "batchable",
     which is used by remotebatch to split the call into separate encoding and
     decoding phases.
     '''
     def plain(*args, **opts):
         batchable = f(*args, **opts)
         encargsorres, encresref = batchable.next()
         if not encresref:
             return encargsorres # a local result in this case
         self = args[0]
         encresref.set(self._submitone(f.func_name, encargsorres))
         return batchable.next()
     setattr(plain, 'batchable', f)
     return plain
 
 # list of nodes encoding / decoding
 
 def decodelist(l, sep=' '):
     if l:
         return map(bin, l.split(sep))
     return []
 
 def encodelist(l, sep=' '):
     return sep.join(map(hex, l))
 
 # batched call argument encoding
 
 def escapearg(plain):
     return (plain
             .replace(':', '::')
             .replace(',', ':,')
             .replace(';', ':;')
             .replace('=', ':='))
 
 def unescapearg(escaped):
     return (escaped
             .replace(':=', '=')
             .replace(':;', ';')
             .replace(':,', ',')
             .replace('::', ':'))
 
 # client side
 
 class wirepeer(peer.peerrepository):
 
     def batch(self):
         return remotebatch(self)
     def _submitbatch(self, req):
         cmds = []
         for op, argsdict in req:
             args = ','.join('%s=%s' % p for p in argsdict.iteritems())
             cmds.append('%s %s' % (op, args))
         rsp = self._call("batch", cmds=';'.join(cmds))
         return rsp.split(';')
     def _submitone(self, op, args):
         return self._call(op, **args)
 
     @batchable
     def lookup(self, key):
         self.requirecap('lookup', _('look up remote revision'))
         f = future()
         yield {'key': encoding.fromlocal(key)}, f
         d = f.value
         success, data = d[:-1].split(" ", 1)
         if int(success):
             yield bin(data)
         self._abort(error.RepoError(data))
 
     @batchable
     def heads(self):
         f = future()
         yield {}, f
         d = f.value
         try:
             yield decodelist(d[:-1])
         except ValueError:
             self._abort(error.ResponseError(_("unexpected response:"), d))
 
     @batchable
     def known(self, nodes):
         f = future()
         yield {'nodes': encodelist(nodes)}, f
         d = f.value
         try:
             yield [bool(int(f)) for f in d]
         except ValueError:
             self._abort(error.ResponseError(_("unexpected response:"), d))
 
     @batchable
     def branchmap(self):
         f = future()
         yield {}, f
         d = f.value
         try:
             branchmap = {}
             for branchpart in d.splitlines():
                 branchname, branchheads = branchpart.split(' ', 1)
                 branchname = encoding.tolocal(urllib.unquote(branchname))
                 branchheads = decodelist(branchheads)
                 branchmap[branchname] = branchheads
             yield branchmap
         except TypeError:
             self._abort(error.ResponseError(_("unexpected response:"), d))
 
     def branches(self, nodes):
         n = encodelist(nodes)
         d = self._call("branches", nodes=n)
         try:
             br = [tuple(decodelist(b)) for b in d.splitlines()]
             return br
         except ValueError:
             self._abort(error.ResponseError(_("unexpected response:"), d))
 
     def between(self, pairs):
         batch = 8 # avoid giant requests
         r = []
         for i in xrange(0, len(pairs), batch):
             n = " ".join([encodelist(p, '-') for p in pairs[i:i + batch]])
             d = self._call("between", pairs=n)
             try:
                 r.extend(l and decodelist(l) or [] for l in d.splitlines())
             except ValueError:
                 self._abort(error.ResponseError(_("unexpected response:"), d))
         return r
 
     @batchable
     def pushkey(self, namespace, key, old, new):
         if not self.capable('pushkey'):
             yield False, None
         f = future()
         self.ui.debug('preparing pushkey for "%s:%s"\n' % (namespace, key))
         yield {'namespace': encoding.fromlocal(namespace),
                'key': encoding.fromlocal(key),
                'old': encoding.fromlocal(old),
                'new': encoding.fromlocal(new)}, f
         d = f.value
         d, output = d.split('\n', 1)
         try:
             d = bool(int(d))
         except ValueError:
             raise error.ResponseError(
                 _('push failed (unexpected response):'), d)
         for l in output.splitlines(True):
             self.ui.status(_('remote: '), l)
         yield d
 
     @batchable
     def listkeys(self, namespace):
         if not self.capable('pushkey'):
             yield {}, None
         f = future()
         self.ui.debug('preparing listkeys for "%s"\n' % namespace)
         yield {'namespace': encoding.fromlocal(namespace)}, f
         d = f.value
         r = {}
         for l in d.splitlines():
             k, v = l.split('\t')
             r[encoding.tolocal(k)] = encoding.tolocal(v)
         yield r
 
     def stream_out(self):
         return self._callstream('stream_out')
 
     def changegroup(self, nodes, kind):
         n = encodelist(nodes)
-        f = self._callstream("changegroup", roots=n)
-        return changegroupmod.unbundle10(self._decompress(f), 'UN')
+        f = self._callcompressable("changegroup", roots=n)
+        return changegroupmod.unbundle10(f, 'UN')
 
     def changegroupsubset(self, bases, heads, kind):
         self.requirecap('changegroupsubset', _('look up remote changes'))
         bases = encodelist(bases)
         heads = encodelist(heads)
-        f = self._callstream("changegroupsubset",
+        f = self._callcompressable("changegroupsubset",
                              bases=bases, heads=heads)
-        return changegroupmod.unbundle10(self._decompress(f), 'UN')
+        return changegroupmod.unbundle10(f, 'UN')
 
     def getbundle(self, source, heads=None, common=None, bundlecaps=None):
         self.requirecap('getbundle', _('look up remote changes'))
         opts = {}
         if heads is not None:
             opts['heads'] = encodelist(heads)
         if common is not None:
             opts['common'] = encodelist(common)
         if bundlecaps is not None:
             opts['bundlecaps'] = ','.join(bundlecaps)
-        f = self._callstream("getbundle", **opts)
-        return changegroupmod.unbundle10(self._decompress(f), 'UN')
+        f = self._callcompressable("getbundle", **opts)
+        return changegroupmod.unbundle10(f, 'UN')
 
     def unbundle(self, cg, heads, source):
         '''Send cg (a readable file-like object representing the
         changegroup to push, typically a chunkbuffer object) to the
         remote server as a bundle. Return an integer indicating the
         result of the push (see localrepository.addchangegroup()).'''
 
         if heads != ['force'] and self.capable('unbundlehash'):
             heads = encodelist(['hashed',
                                 util.sha1(''.join(sorted(heads))).digest()])
         else:
             heads = encodelist(heads)
 
         ret, output = self._callpush("unbundle", cg, heads=heads)
         if ret == "":
             raise error.ResponseError(
                 _('push failed:'), output)
         try:
             ret = int(ret)
         except ValueError:
             raise error.ResponseError(
                 _('push failed (unexpected response):'), ret)
 
         for l in output.splitlines(True):
             self.ui.status(_('remote: '), l)
         return ret
 
     def debugwireargs(self, one, two, three=None, four=None, five=None):
         # don't pass optional arguments left at their default value
         opts = {}
         if three is not None:
             opts['three'] = three
         if four is not None:
             opts['four'] = four
         return self._call('debugwireargs', one=one, two=two, **opts)
 
     def _call(self, cmd, **args):
         """execute <cmd> on the server
 
         The command is expected to return a simple string.
 
         returns the server reply as a string."""
         raise NotImplementedError()
 
     def _callstream(self, cmd, **args):
         """execute <cmd> on the server
 
         The command is expected to return a stream.
 
         returns the server reply as a file like object."""
         raise NotImplementedError()
 
+    def _callcompressable(self, cmd, **args):
+        """execute <cmd> on the server
+
+        The command is expected to return a stream.
+
+        The stream may have been compressed in some implementaitons. This
+        function takes care of the decompression. This is the only difference
+        with _callstream.
+
+        returns the server reply as a file like object.
+        """
+        raise NotImplementedError()
+
     def _callpush(self, cmd, fp, **args):
         """execute a <cmd> on server
 
         The command is expected to be related to a push. Push has a special
         return method.
 
         returns the server reply as a (ret, output) tuple. ret is either
         empty (error) or a stringified int.
         """
         raise NotImplementedError()
 
     def _abort(self, exception):
         """clearly abort the wire protocol connection and raise the exception
         """
         raise NotImplementedError()
 
-
-    def _decompress(self, stream):
-        """decompress a received stream
-        """
-        raise NotImplementedError()
-
 # server side
 
 # wire protocol command can either return a string or one of these classes.
 class streamres(object):
     """wireproto reply: binary stream
 
     The call was successful and the result is a stream.
     Iterate on the `self.gen` attribute to retrieve chunks.
     """
     def __init__(self, gen):
         self.gen = gen
 
 class pushres(object):
     """wireproto reply: success with simple integer return
 
     The call was successful and returned an integer contained in `self.res`.
     """
     def __init__(self, res):
         self.res = res
 
 class pusherr(object):
     """wireproto reply: failure
 
     The call failed. The `self.res` attribute contains the error message.
     """
     def __init__(self, res):
         self.res = res
 
 class ooberror(object):
     """wireproto reply: failure of a batch of operation
 
     Something failed during a batch call. The error message is stored in
     `self.message`.
     """
     def __init__(self, message):
         self.message = message
 
 def dispatch(repo, proto, command):
     repo = repo.filtered("served")
     func, spec = commands[command]
     args = proto.getargs(spec)
     return func(repo, proto, *args)
 
 def options(cmd, keys, others):
     opts = {}
     for k in keys:
         if k in others:
             opts[k] = others[k]
             del others[k]
     if others:
         sys.stderr.write("abort: %s got unexpected arguments %s\n"
                          % (cmd, ",".join(others)))
     return opts
 
 def batch(repo, proto, cmds, others):
     repo = repo.filtered("served")
     res = []
     for pair in cmds.split(';'):
         op, args = pair.split(' ', 1)
         vals = {}
         for a in args.split(','):
             if a:
                 n, v = a.split('=')
                 vals[n] = unescapearg(v)
         func, spec = commands[op]
         if spec:
             keys = spec.split()
             data = {}
             for k in keys:
                 if k == '*':
                     star = {}
                     for key in vals.keys():
                         if key not in keys:
                             star[key] = vals[key]
                     data['*'] = star
                 else:
                     data[k] = vals[k]
             result = func(repo, proto, *[data[k] for k in keys])
         else:
             result = func(repo, proto)
         if isinstance(result, ooberror):
             return result
         res.append(escapearg(result))
     return ';'.join(res)
 
 def between(repo, proto, pairs):
     pairs = [decodelist(p, '-') for p in pairs.split(" ")]
     r = []
     for b in repo.between(pairs):
         r.append(encodelist(b) + "\n")
     return "".join(r)
 
 def branchmap(repo, proto):
     branchmap = repo.branchmap()
     heads = []
     for branch, nodes in branchmap.iteritems():
         branchname = urllib.quote(encoding.fromlocal(branch))
         branchnodes = encodelist(nodes)
         heads.append('%s %s' % (branchname, branchnodes))
     return '\n'.join(heads)
 
 def branches(repo, proto, nodes):
     nodes = decodelist(nodes)
     r = []
     for b in repo.branches(nodes):
         r.append(encodelist(b) + "\n")
     return "".join(r)
 
 
 wireprotocaps = ['lookup', 'changegroupsubset', 'branchmap', 'pushkey',
                  'known', 'getbundle', 'unbundlehash', 'batch']
 
 def _capabilities(repo, proto):
     """return a list of capabilities for a repo
 
     This function exists to allow extensions to easily wrap capabilities
     computation
 
     - returns a lists: easy to alter
     - change done here will be propagated to both `capabilities` and `hello`
       command without any other effort. without any other action needed.
     """
     # copy to prevent modification of the global list
     caps = list(wireprotocaps)
     if _allowstream(repo.ui):
         if repo.ui.configbool('server', 'preferuncompressed', False):
             caps.append('stream-preferred')
         requiredformats = repo.requirements & repo.supportedformats
         # if our local revlogs are just revlogv1, add 'stream' cap
         if not requiredformats - set(('revlogv1',)):
             caps.append('stream')
         # otherwise, add 'streamreqs' detailing our local revlog format
         else:
             caps.append('streamreqs=%s' % ','.join(requiredformats))
     caps.append('unbundle=%s' % ','.join(changegroupmod.bundlepriority))
     caps.append('httpheader=1024')
     return caps
 
 # If you are writting and extension and consider wrapping this function. Wrap
 # `_capabilities` instead.
 def capabilities(repo, proto):
     return ' '.join(_capabilities(repo, proto))
 
 def changegroup(repo, proto, roots):
     nodes = decodelist(roots)
     cg = repo.changegroup(nodes, 'serve')
     return streamres(proto.groupchunks(cg))
 
 def changegroupsubset(repo, proto, bases, heads):
     bases = decodelist(bases)
     heads = decodelist(heads)
     cg = repo.changegroupsubset(bases, heads, 'serve')
     return streamres(proto.groupchunks(cg))
 
 def debugwireargs(repo, proto, one, two, others):
     # only accept optional args from the known set
     opts = options('debugwireargs', ['three', 'four'], others)
     return repo.debugwireargs(one, two, **opts)
 
 def getbundle(repo, proto, others):
     opts = options('getbundle', ['heads', 'common', 'bundlecaps'], others)
     for k, v in opts.iteritems():
         if k in ('heads', 'common'):
             opts[k] = decodelist(v)
         elif k == 'bundlecaps':
             opts[k] = set(v.split(','))
     cg = repo.getbundle('serve', **opts)
     return streamres(proto.groupchunks(cg))
 
 def heads(repo, proto):
     h = repo.heads()
     return encodelist(h) + "\n"
 
 def hello(repo, proto):
     '''the hello command returns a set of lines describing various
     interesting things about the server, in an RFC822-like format.
     Currently the only one defined is "capabilities", which
     consists of a line in the form:
 
     capabilities: space separated list of tokens
     '''
     return "capabilities: %s\n" % (capabilities(repo, proto))
 
 def listkeys(repo, proto, namespace):
     d = repo.listkeys(encoding.tolocal(namespace)).items()
     t = '\n'.join(['%s\t%s' % (encoding.fromlocal(k), encoding.fromlocal(v))
                    for k, v in d])
     return t
 
 def lookup(repo, proto, key):
     try:
         k = encoding.tolocal(key)
         c = repo[k]
         r = c.hex()
         success = 1
     except Exception, inst:
         r = str(inst)
         success = 0
     return "%s %s\n" % (success, r)
 
 def known(repo, proto, nodes, others):
     return ''.join(b and "1" or "0" for b in repo.known(decodelist(nodes)))
 
 def pushkey(repo, proto, namespace, key, old, new):
     # compatibility with pre-1.8 clients which were accidentally
     # sending raw binary nodes rather than utf-8-encoded hex
     if len(new) == 20 and new.encode('string-escape') != new:
         # looks like it could be a binary node
         try:
             new.decode('utf-8')
             new = encoding.tolocal(new) # but cleanly decodes as UTF-8
         except UnicodeDecodeError:
             pass # binary, leave unmodified
     else:
         new = encoding.tolocal(new) # normal path
 
     if util.safehasattr(proto, 'restore'):
 
         proto.redirect()
 
         try:
             r = repo.pushkey(encoding.tolocal(namespace), encoding.tolocal(key),
                              encoding.tolocal(old), new) or False
         except util.Abort:
             r = False
 
         output = proto.restore()
 
         return '%s\n%s' % (int(r), output)
 
     r = repo.pushkey(encoding.tolocal(namespace), encoding.tolocal(key),
                      encoding.tolocal(old), new)
     return '%s\n' % int(r)
 
 def _allowstream(ui):
     return ui.configbool('server', 'uncompressed', True, untrusted=True)
 
 def _walkstreamfiles(repo):
     # this is it's own function so extensions can override it
     return repo.store.walk()
 
 def stream(repo, proto):
     '''If the server supports streaming clone, it advertises the "stream"
     capability with a value representing the version and flags of the repo
     it is serving. Client checks to see if it understands the format.
 
     The format is simple: the server writes out a line with the amount
     of files, then the total amount of bytes to be transferred (separated
     by a space). Then, for each file, the server first writes the filename
     and filesize (separated by the null character), then the file contents.
     '''
 
     if not _allowstream(repo.ui):
         return '1\n'
 
     entries = []
     total_bytes = 0
     try:
         # get consistent snapshot of repo, lock during scan
         lock = repo.lock()
         try:
             repo.ui.debug('scanning\n')
             for name, ename, size in _walkstreamfiles(repo):
                 if size:
                     entries.append((name, size))
                     total_bytes += size
         finally:
             lock.release()
     except error.LockError:
         return '2\n' # error: 2
 
     def streamer(repo, entries, total):
         '''stream out all metadata files in repository.'''
         yield '0\n' # success
         repo.ui.debug('%d files, %d bytes to transfer\n' %
                       (len(entries), total_bytes))
         yield '%d %d\n' % (len(entries), total_bytes)
 
         sopener = repo.sopener
         oldaudit = sopener.mustaudit
         debugflag = repo.ui.debugflag
         sopener.mustaudit = False
 
         try:
             for name, size in entries:
                 if debugflag:
                     repo.ui.debug('sending %s (%d bytes)\n' % (name, size))
                 # partially encode name over the wire for backwards compat
                 yield '%s\0%d\n' % (store.encodedir(name), size)
                 if size <= 65536:
                     fp = sopener(name)
                     try:
                         data = fp.read(size)
                     finally:
                         fp.close()
                     yield data
                 else:
                     for chunk in util.filechunkiter(sopener(name), limit=size):
                         yield chunk
         # replace with "finally:" when support for python 2.4 has been dropped
         except Exception:
             sopener.mustaudit = oldaudit
             raise
         sopener.mustaudit = oldaudit
 
     return streamres(streamer(repo, entries, total_bytes))
 
 def unbundle(repo, proto, heads):
     their_heads = decodelist(heads)
 
     def check_heads():
         heads = repo.heads()
         heads_hash = util.sha1(''.join(sorted(heads))).digest()
         return (their_heads == ['force'] or their_heads == heads or
                 their_heads == ['hashed', heads_hash])
 
     proto.redirect()
 
     # fail early if possible
     if not check_heads():
         return pusherr('repository changed while preparing changes - '
                        'please try again')
 
     # write bundle data to temporary file because it can be big
     fd, tempname = tempfile.mkstemp(prefix='hg-unbundle-')
     fp = os.fdopen(fd, 'wb+')
     r = 0
     try:
         proto.getfile(fp)
         lock = repo.lock()
         try:
             if not check_heads():
                 # someone else committed/pushed/unbundled while we
                 # were transferring data
                 return pusherr('repository changed while uploading changes - '
                                'please try again')
 
             # push can proceed
             fp.seek(0)
             gen = changegroupmod.readbundle(fp, None)
 
             try:
                 r = repo.addchangegroup(gen, 'serve', proto._client())
             except util.Abort, inst:
                 sys.stderr.write("abort: %s\n" % inst)
         finally:
             lock.release()
         return pushres(r)
 
     finally:
         fp.close()
         os.unlink(tempname)
 
 commands = {
     'batch': (batch, 'cmds *'),
     'between': (between, 'pairs'),
     'branchmap': (branchmap, ''),
     'branches': (branches, 'nodes'),
     'capabilities': (capabilities, ''),
     'changegroup': (changegroup, 'roots'),
     'changegroupsubset': (changegroupsubset, 'bases heads'),
     'debugwireargs': (debugwireargs, 'one two *'),
     'getbundle': (getbundle, '*'),
     'heads': (heads, ''),
     'hello': (hello, ''),
     'known': (known, 'nodes *'),
     'listkeys': (listkeys, 'namespace'),
     'lookup': (lookup, 'key'),
     'pushkey': (pushkey, 'namespace key old new'),
     'stream_out': (stream, ''),
     'unbundle': (unbundle, 'heads'),
 }