wireprototypes: move baseprotocolhandler from wireprotoserver

This is needed to prevent a cycle in an upcoming commit.

Differential Revision: https://phab.mercurial-scm.org/D2384

mercurial/wireprotoserver.py

@@ -1,651 +1,601 b''
 # Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
 # Copyright 2005-2007 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.
 
 from __future__ import absolute_import
 
-import abc
 import contextlib
 import struct
 import sys
 
 from .i18n import _
 from . import (
     encoding,
     error,
     hook,
     pycompat,
     util,
     wireproto,
     wireprototypes,
 )
 
 stringio = util.stringio
 
 urlerr = util.urlerr
 urlreq = util.urlreq
 
 HTTP_OK = 200
 
 HGTYPE = 'application/mercurial-0.1'
 HGTYPE2 = 'application/mercurial-0.2'
 HGERRTYPE = 'application/hg-error'
 
 # Names of the SSH protocol implementations.
 SSHV1 = 'ssh-v1'
 # This is advertised over the wire. Incremental the counter at the end
 # to reflect BC breakages.
 SSHV2 = 'exp-ssh-v2-0001'
 
-class baseprotocolhandler(object):
-    """Abstract base class for wire protocol handlers.
-
-    A wire protocol handler serves as an interface between protocol command
-    handlers and the wire protocol transport layer. Protocol handlers provide
-    methods to read command arguments, redirect stdio for the duration of
-    the request, handle response types, etc.
-    """
-
-    __metaclass__ = abc.ABCMeta
-
-    @abc.abstractproperty
-    def name(self):
-        """The name of the protocol implementation.
-
-        Used for uniquely identifying the transport type.
-        """
-
-    @abc.abstractmethod
-    def getargs(self, args):
-        """return the value for arguments in <args>
-
-        returns a list of values (same order as <args>)"""
-
-    @abc.abstractmethod
-    def forwardpayload(self, fp):
-        """Read the raw payload and forward to a file.
-
-        The payload is read in full before the function returns.
-        """
-
-    @abc.abstractmethod
-    def mayberedirectstdio(self):
-        """Context manager to possibly redirect stdio.
-
-        The context manager yields a file-object like object that receives
-        stdout and stderr output when the context manager is active. Or it
-        yields ``None`` if no I/O redirection occurs.
-
-        The intent of this context manager is to capture stdio output
-        so it may be sent in the response. Some transports support streaming
-        stdio to the client in real time. For these transports, stdio output
-        won't be captured.
-        """
-
-    @abc.abstractmethod
-    def client(self):
-        """Returns a string representation of this client (as bytes)."""
-
 def decodevaluefromheaders(req, headerprefix):
     """Decode a long value from multiple HTTP request headers.
 
     Returns the value as a bytes, not a str.
     """
     chunks = []
     i = 1
     prefix = headerprefix.upper().replace(r'-', r'_')
     while True:
         v = req.env.get(r'HTTP_%s_%d' % (prefix, i))
         if v is None:
             break
         chunks.append(pycompat.bytesurl(v))
         i += 1
 
     return ''.join(chunks)
 
-class httpv1protocolhandler(baseprotocolhandler):
+class httpv1protocolhandler(wireprototypes.baseprotocolhandler):
     def __init__(self, req, ui):
         self._req = req
         self._ui = ui
 
     @property
     def name(self):
         return 'http-v1'
 
     def getargs(self, args):
         knownargs = self._args()
         data = {}
         keys = args.split()
         for k in keys:
             if k == '*':
                 star = {}
                 for key in knownargs.keys():
                     if key != 'cmd' and key not in keys:
                         star[key] = knownargs[key][0]
                 data['*'] = star
             else:
                 data[k] = knownargs[k][0]
         return [data[k] for k in keys]
 
     def _args(self):
         args = util.rapply(pycompat.bytesurl, self._req.form.copy())
         postlen = int(self._req.env.get(r'HTTP_X_HGARGS_POST', 0))
         if postlen:
             args.update(urlreq.parseqs(
                 self._req.read(postlen), keep_blank_values=True))
             return args
 
         argvalue = decodevaluefromheaders(self._req, r'X-HgArg')
         args.update(urlreq.parseqs(argvalue, keep_blank_values=True))
         return args
 
     def forwardpayload(self, fp):
         if r'HTTP_CONTENT_LENGTH' in self._req.env:
             length = int(self._req.env[r'HTTP_CONTENT_LENGTH'])
         else:
             length = int(self._req.env[r'CONTENT_LENGTH'])
         # If httppostargs is used, we need to read Content-Length
         # minus the amount that was consumed by args.
         length -= int(self._req.env.get(r'HTTP_X_HGARGS_POST', 0))
         for s in util.filechunkiter(self._req, limit=length):
             fp.write(s)
 
     @contextlib.contextmanager
     def mayberedirectstdio(self):
         oldout = self._ui.fout
         olderr = self._ui.ferr
 
         out = util.stringio()
 
         try:
             self._ui.fout = out
             self._ui.ferr = out
             yield out
         finally:
             self._ui.fout = oldout
             self._ui.ferr = olderr
 
     def client(self):
         return 'remote:%s:%s:%s' % (
             self._req.env.get('wsgi.url_scheme') or 'http',
             urlreq.quote(self._req.env.get('REMOTE_HOST', '')),
             urlreq.quote(self._req.env.get('REMOTE_USER', '')))
 
 # This method exists mostly so that extensions like remotefilelog can
 # disable a kludgey legacy method only over http. As of early 2018,
 # there are no other known users, so with any luck we can discard this
 # hook if remotefilelog becomes a first-party extension.
 def iscmd(cmd):
     return cmd in wireproto.commands
 
 def parsehttprequest(repo, req, query):
     """Parse the HTTP request for a wire protocol request.
 
     If the current request appears to be a wire protocol request, this
     function returns a dict with details about that request, including
     an ``abstractprotocolserver`` instance suitable for handling the
     request. Otherwise, ``None`` is returned.
 
     ``req`` is a ``wsgirequest`` instance.
     """
     # HTTP version 1 wire protocol requests are denoted by a "cmd" query
     # string parameter. If it isn't present, this isn't a wire protocol
     # request.
     if r'cmd' not in req.form:
         return None
 
     cmd = pycompat.sysbytes(req.form[r'cmd'][0])
 
     # The "cmd" request parameter is used by both the wire protocol and hgweb.
     # While not all wire protocol commands are available for all transports,
     # if we see a "cmd" value that resembles a known wire protocol command, we
     # route it to a protocol handler. This is better than routing possible
     # wire protocol requests to hgweb because it prevents hgweb from using
     # known wire protocol commands and it is less confusing for machine
     # clients.
     if not iscmd(cmd):
         return None
 
     proto = httpv1protocolhandler(req, repo.ui)
 
     return {
         'cmd': cmd,
         'proto': proto,
         'dispatch': lambda: _callhttp(repo, req, proto, cmd),
         'handleerror': lambda ex: _handlehttperror(ex, req, cmd),
     }
 
 def _httpresponsetype(ui, req, prefer_uncompressed):
     """Determine the appropriate response type and compression settings.
 
     Returns a tuple of (mediatype, compengine, engineopts).
     """
     # Determine the response media type and compression engine based
     # on the request parameters.
     protocaps = decodevaluefromheaders(req, r'X-HgProto').split(' ')
 
     if '0.2' in protocaps:
         # All clients are expected to support uncompressed data.
         if prefer_uncompressed:
             return HGTYPE2, util._noopengine(), {}
 
         # Default as defined by wire protocol spec.
         compformats = ['zlib', 'none']
         for cap in protocaps:
             if cap.startswith('comp='):
                 compformats = cap[5:].split(',')
                 break
 
         # Now find an agreed upon compression format.
         for engine in wireproto.supportedcompengines(ui, util.SERVERROLE):
             if engine.wireprotosupport().name in compformats:
                 opts = {}
                 level = ui.configint('server', '%slevel' % engine.name())
                 if level is not None:
                     opts['level'] = level
 
                 return HGTYPE2, engine, opts
 
         # No mutually supported compression format. Fall back to the
         # legacy protocol.
 
     # Don't allow untrusted settings because disabling compression or
     # setting a very high compression level could lead to flooding
     # the server's network or CPU.
     opts = {'level': ui.configint('server', 'zliblevel')}
     return HGTYPE, util.compengines['zlib'], opts
 
 def _callhttp(repo, req, proto, cmd):
     def genversion2(gen, engine, engineopts):
         # application/mercurial-0.2 always sends a payload header
         # identifying the compression engine.
         name = engine.wireprotosupport().name
         assert 0 < len(name) < 256
         yield struct.pack('B', len(name))
         yield name
 
         for chunk in gen:
             yield chunk
 
     rsp = wireproto.dispatch(repo, proto, cmd)
 
     if not wireproto.commands.commandavailable(cmd, proto):
         req.respond(HTTP_OK, HGERRTYPE,
                     body=_('requested wire protocol command is not available '
                            'over HTTP'))
         return []
 
     if isinstance(rsp, bytes):
         req.respond(HTTP_OK, HGTYPE, body=rsp)
         return []
     elif isinstance(rsp, wireprototypes.bytesresponse):
         req.respond(HTTP_OK, HGTYPE, body=rsp.data)
         return []
     elif isinstance(rsp, wireprototypes.streamreslegacy):
         gen = rsp.gen
         req.respond(HTTP_OK, HGTYPE)
         return gen
     elif isinstance(rsp, wireprototypes.streamres):
         gen = rsp.gen
 
         # This code for compression should not be streamres specific. It
         # is here because we only compress streamres at the moment.
         mediatype, engine, engineopts = _httpresponsetype(
             repo.ui, req, rsp.prefer_uncompressed)
         gen = engine.compressstream(gen, engineopts)
 
         if mediatype == HGTYPE2:
             gen = genversion2(gen, engine, engineopts)
 
         req.respond(HTTP_OK, mediatype)
         return gen
     elif isinstance(rsp, wireprototypes.pushres):
         rsp = '%d\n%s' % (rsp.res, rsp.output)
         req.respond(HTTP_OK, HGTYPE, body=rsp)
         return []
     elif isinstance(rsp, wireprototypes.pusherr):
         # This is the httplib workaround documented in _handlehttperror().
         req.drain()
 
         rsp = '0\n%s\n' % rsp.res
         req.respond(HTTP_OK, HGTYPE, body=rsp)
         return []
     elif isinstance(rsp, wireprototypes.ooberror):
         rsp = rsp.message
         req.respond(HTTP_OK, HGERRTYPE, body=rsp)
         return []
     raise error.ProgrammingError('hgweb.protocol internal failure', rsp)
 
 def _handlehttperror(e, req, cmd):
     """Called when an ErrorResponse is raised during HTTP request processing."""
 
     # Clients using Python's httplib are stateful: the HTTP client
     # won't process an HTTP response until all request data is
     # sent to the server. The intent of this code is to ensure
     # we always read HTTP request data from the client, thus
     # ensuring httplib transitions to a state that allows it to read
     # the HTTP response. In other words, it helps prevent deadlocks
     # on clients using httplib.
 
     if (req.env[r'REQUEST_METHOD'] == r'POST' and
         # But not if Expect: 100-continue is being used.
         (req.env.get('HTTP_EXPECT',
                      '').lower() != '100-continue') or
         # Or the non-httplib HTTP library is being advertised by
         # the client.
         req.env.get('X-HgHttp2', '')):
         req.drain()
     else:
         req.headers.append((r'Connection', r'Close'))
 
     # TODO This response body assumes the failed command was
     # "unbundle." That assumption is not always valid.
     req.respond(e, HGTYPE, body='0\n%s\n' % pycompat.bytestr(e))
 
     return ''
 
 def _sshv1respondbytes(fout, value):
     """Send a bytes response for protocol version 1."""
     fout.write('%d\n' % len(value))
     fout.write(value)
     fout.flush()
 
 def _sshv1respondstream(fout, source):
     write = fout.write
     for chunk in source.gen:
         write(chunk)
     fout.flush()
 
 def _sshv1respondooberror(fout, ferr, rsp):
     ferr.write(b'%s\n-\n' % rsp)
     ferr.flush()
     fout.write(b'\n')
     fout.flush()
 
-class sshv1protocolhandler(baseprotocolhandler):
+class sshv1protocolhandler(wireprototypes.baseprotocolhandler):
     """Handler for requests services via version 1 of SSH protocol."""
     def __init__(self, ui, fin, fout):
         self._ui = ui
         self._fin = fin
         self._fout = fout
 
     @property
     def name(self):
         return SSHV1
 
     def getargs(self, args):
         data = {}
         keys = args.split()
         for n in xrange(len(keys)):
             argline = self._fin.readline()[:-1]
             arg, l = argline.split()
             if arg not in keys:
                 raise error.Abort(_("unexpected parameter %r") % arg)
             if arg == '*':
                 star = {}
                 for k in xrange(int(l)):
                     argline = self._fin.readline()[:-1]
                     arg, l = argline.split()
                     val = self._fin.read(int(l))
                     star[arg] = val
                 data['*'] = star
             else:
                 val = self._fin.read(int(l))
                 data[arg] = val
         return [data[k] for k in keys]
 
     def forwardpayload(self, fpout):
         # The file is in the form:
         #
         # <chunk size>\n<chunk>
         # ...
         # 0\n
         _sshv1respondbytes(self._fout, b'')
         count = int(self._fin.readline())
         while count:
             fpout.write(self._fin.read(count))
             count = int(self._fin.readline())
 
     @contextlib.contextmanager
     def mayberedirectstdio(self):
         yield None
 
     def client(self):
         client = encoding.environ.get('SSH_CLIENT', '').split(' ', 1)[0]
         return 'remote:ssh:' + client
 
 class sshv2protocolhandler(sshv1protocolhandler):
     """Protocol handler for version 2 of the SSH protocol."""
 
 def _runsshserver(ui, repo, fin, fout):
     # This function operates like a state machine of sorts. The following
     # states are defined:
     #
     # protov1-serving
     #    Server is in protocol version 1 serving mode. Commands arrive on
     #    new lines. These commands are processed in this state, one command
     #    after the other.
     #
     # protov2-serving
     #    Server is in protocol version 2 serving mode.
     #
     # upgrade-initial
     #    The server is going to process an upgrade request.
     #
     # upgrade-v2-filter-legacy-handshake
     #    The protocol is being upgraded to version 2. The server is expecting
     #    the legacy handshake from version 1.
     #
     # upgrade-v2-finish
     #    The upgrade to version 2 of the protocol is imminent.
     #
     # shutdown
     #    The server is shutting down, possibly in reaction to a client event.
     #
     # And here are their transitions:
     #
     # protov1-serving -> shutdown
     #    When server receives an empty request or encounters another
     #    error.
     #
     # protov1-serving -> upgrade-initial
     #    An upgrade request line was seen.
     #
     # upgrade-initial -> upgrade-v2-filter-legacy-handshake
     #    Upgrade to version 2 in progress. Server is expecting to
     #    process a legacy handshake.
     #
     # upgrade-v2-filter-legacy-handshake -> shutdown
     #    Client did not fulfill upgrade handshake requirements.
     #
     # upgrade-v2-filter-legacy-handshake -> upgrade-v2-finish
     #    Client fulfilled version 2 upgrade requirements. Finishing that
     #    upgrade.
     #
     # upgrade-v2-finish -> protov2-serving
     #    Protocol upgrade to version 2 complete. Server can now speak protocol
     #    version 2.
     #
     # protov2-serving -> protov1-serving
     #    Ths happens by default since protocol version 2 is the same as
     #    version 1 except for the handshake.
 
     state = 'protov1-serving'
     proto = sshv1protocolhandler(ui, fin, fout)
     protoswitched = False
 
     while True:
         if state == 'protov1-serving':
             # Commands are issued on new lines.
             request = fin.readline()[:-1]
 
             # Empty lines signal to terminate the connection.
             if not request:
                 state = 'shutdown'
                 continue
 
             # It looks like a protocol upgrade request. Transition state to
             # handle it.
             if request.startswith(b'upgrade '):
                 if protoswitched:
                     _sshv1respondooberror(fout, ui.ferr,
                                           b'cannot upgrade protocols multiple '
                                           b'times')
                     state = 'shutdown'
                     continue
 
                 state = 'upgrade-initial'
                 continue
 
             available = wireproto.commands.commandavailable(request, proto)
 
             # This command isn't available. Send an empty response and go
             # back to waiting for a new command.
             if not available:
                 _sshv1respondbytes(fout, b'')
                 continue
 
             rsp = wireproto.dispatch(repo, proto, request)
 
             if isinstance(rsp, bytes):
                 _sshv1respondbytes(fout, rsp)
             elif isinstance(rsp, wireprototypes.bytesresponse):
                 _sshv1respondbytes(fout, rsp.data)
             elif isinstance(rsp, wireprototypes.streamres):
                 _sshv1respondstream(fout, rsp)
             elif isinstance(rsp, wireprototypes.streamreslegacy):
                 _sshv1respondstream(fout, rsp)
             elif isinstance(rsp, wireprototypes.pushres):
                 _sshv1respondbytes(fout, b'')
                 _sshv1respondbytes(fout, b'%d' % rsp.res)
             elif isinstance(rsp, wireprototypes.pusherr):
                 _sshv1respondbytes(fout, rsp.res)
             elif isinstance(rsp, wireprototypes.ooberror):
                 _sshv1respondooberror(fout, ui.ferr, rsp.message)
             else:
                 raise error.ProgrammingError('unhandled response type from '
                                              'wire protocol command: %s' % rsp)
 
         # For now, protocol version 2 serving just goes back to version 1.
         elif state == 'protov2-serving':
             state = 'protov1-serving'
             continue
 
         elif state == 'upgrade-initial':
             # We should never transition into this state if we've switched
             # protocols.
             assert not protoswitched
             assert proto.name == SSHV1
 
             # Expected: upgrade <token> <capabilities>
             # If we get something else, the request is malformed. It could be
             # from a future client that has altered the upgrade line content.
             # We treat this as an unknown command.
             try:
                 token, caps = request.split(b' ')[1:]
             except ValueError:
                 _sshv1respondbytes(fout, b'')
                 state = 'protov1-serving'
                 continue
 
             # Send empty response if we don't support upgrading protocols.
             if not ui.configbool('experimental', 'sshserver.support-v2'):
                 _sshv1respondbytes(fout, b'')
                 state = 'protov1-serving'
                 continue
 
             try:
                 caps = urlreq.parseqs(caps)
             except ValueError:
                 _sshv1respondbytes(fout, b'')
                 state = 'protov1-serving'
                 continue
 
             # We don't see an upgrade request to protocol version 2. Ignore
             # the upgrade request.
             wantedprotos = caps.get(b'proto', [b''])[0]
             if SSHV2 not in wantedprotos:
                 _sshv1respondbytes(fout, b'')
                 state = 'protov1-serving'
                 continue
 
             # It looks like we can honor this upgrade request to protocol 2.
             # Filter the rest of the handshake protocol request lines.
             state = 'upgrade-v2-filter-legacy-handshake'
             continue
 
         elif state == 'upgrade-v2-filter-legacy-handshake':
             # Client should have sent legacy handshake after an ``upgrade``
             # request. Expected lines:
             #
             #    hello
             #    between
             #    pairs 81
             #    0000...-0000...
 
             ok = True
             for line in (b'hello', b'between', b'pairs 81'):
                 request = fin.readline()[:-1]
 
                 if request != line:
                     _sshv1respondooberror(fout, ui.ferr,
                                           b'malformed handshake protocol: '
                                           b'missing %s' % line)
                     ok = False
                     state = 'shutdown'
                     break
 
             if not ok:
                 continue
 
             request = fin.read(81)
             if request != b'%s-%s' % (b'0' * 40, b'0' * 40):
                 _sshv1respondooberror(fout, ui.ferr,
                                       b'malformed handshake protocol: '
                                       b'missing between argument value')
                 state = 'shutdown'
                 continue
 
             state = 'upgrade-v2-finish'
             continue
 
         elif state == 'upgrade-v2-finish':
             # Send the upgrade response.
             fout.write(b'upgraded %s %s\n' % (token, SSHV2))
             servercaps = wireproto.capabilities(repo, proto)
             rsp = b'capabilities: %s' % servercaps.data
             fout.write(b'%d\n%s\n' % (len(rsp), rsp))
             fout.flush()
 
             proto = sshv2protocolhandler(ui, fin, fout)
             protoswitched = True
 
             state = 'protov2-serving'
             continue
 
         elif state == 'shutdown':
             break
 
         else:
             raise error.ProgrammingError('unhandled ssh server state: %s' %
                                          state)
 
 class sshserver(object):
     def __init__(self, ui, repo):
         self._ui = ui
         self._repo = repo
         self._fin = ui.fin
         self._fout = ui.fout
 
         hook.redirect(True)
         ui.fout = repo.ui.fout = ui.ferr
 
         # Prevent insertion/deletion of CRs
         util.setbinary(self._fin)
         util.setbinary(self._fout)
 
     def serve_forever(self):
         _runsshserver(self._ui, self._repo, self._fin, self._fout)
         sys.exit(0)

mercurial/wireprototypes.py

@@ -1,66 +1,117 b''
 # Copyright 2018 Gregory Szorc <[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 __future__ import absolute_import
 
+import abc
+
 class bytesresponse(object):
     """A wire protocol response consisting of raw bytes."""
     def __init__(self, data):
         self.data = data
 
 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
 
 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, output):
         self.res = res
         self.output = output
 
 class pusherr(object):
     """wireproto reply: failure
 
     The call failed. The `self.res` attribute contains the error message.
     """
     def __init__(self, res, output):
         self.res = res
         self.output = output
 
 class streamres(object):
     """wireproto reply: binary stream
 
     The call was successful and the result is a stream.
 
     Accepts a generator containing chunks of data to be sent to the client.
 
     ``prefer_uncompressed`` indicates that the data is expected to be
     uncompressable and that the stream should therefore use the ``none``
     engine.
     """
     def __init__(self, gen=None, prefer_uncompressed=False):
         self.gen = gen
         self.prefer_uncompressed = prefer_uncompressed
 
 class streamreslegacy(object):
     """wireproto reply: uncompressed binary stream
 
     The call was successful and the result is a stream.
 
     Accepts a generator containing chunks of data to be sent to the client.
 
     Like ``streamres``, but sends an uncompressed data for "version 1" clients
     using the application/mercurial-0.1 media type.
     """
     def __init__(self, gen=None):
         self.gen = gen
+
+class baseprotocolhandler(object):
+    """Abstract base class for wire protocol handlers.
+
+    A wire protocol handler serves as an interface between protocol command
+    handlers and the wire protocol transport layer. Protocol handlers provide
+    methods to read command arguments, redirect stdio for the duration of
+    the request, handle response types, etc.
+    """
+
+    __metaclass__ = abc.ABCMeta
+
+    @abc.abstractproperty
+    def name(self):
+        """The name of the protocol implementation.
+
+        Used for uniquely identifying the transport type.
+        """
+
+    @abc.abstractmethod
+    def getargs(self, args):
+        """return the value for arguments in <args>
+
+        returns a list of values (same order as <args>)"""
+
+    @abc.abstractmethod
+    def forwardpayload(self, fp):
+        """Read the raw payload and forward to a file.
+
+        The payload is read in full before the function returns.
+        """
+
+    @abc.abstractmethod
+    def mayberedirectstdio(self):
+        """Context manager to possibly redirect stdio.
+
+        The context manager yields a file-object like object that receives
+        stdout and stderr output when the context manager is active. Or it
+        yields ``None`` if no I/O redirection occurs.
+
+        The intent of this context manager is to capture stdio output
+        so it may be sent in the response. Some transports support streaming
+        stdio to the client in real time. For these transports, stdio output
+        won't be captured.
+        """
+
+    @abc.abstractmethod
+    def client(self):
+        """Returns a string representation of this client (as bytes)."""