wireproto: client reactor support for receiving frames

We can now feed received frames into the client reactor and it will
validate their sanity, dispatch them appropriately.

The hacky HTTP peer has been updated to use the new code. No
existing tests changed, somewhat proving the code works as
expected.

Rudimentary unit tests for the new functionality have been
implemented.

Differential Revision: https://phab.mercurial-scm.org/D3224

mercurial/httppeer.py

@@ -551,18 +551,19 class httpv2peer(object):
 
             self.ui.note(_('received %r\n') % frame)
 
-            if frame.typeid == wireprotoframing.FRAME_TYPE_BYTES_RESPONSE:
-                if frame.flags & wireprotoframing.FLAG_BYTES_RESPONSE_CBOR:
-                    payload = util.bytesio(frame.payload)
+            action, meta = reactor.onframerecv(frame)
+
+            if action == 'responsedata':
+                if meta['cbor']:
+                    payload = util.bytesio(meta['data'])
 
                     decoder = cbor.CBORDecoder(payload)
-                    while payload.tell() + 1 < len(frame.payload):
+                    while payload.tell() + 1 < len(meta['data']):
                         results.append(decoder.decode())
                 else:
-                    results.append(frame.payload)
+                    results.append(meta['data'])
             else:
-                error.ProgrammingError('unhandled frame type: %d' %
-                                       frame.typeid)
+                error.ProgrammingError('unhandled action: %s' % action)
 
         return results
 

mercurial/wireprotoframing.py

@@ -922,6 +922,7 class clientreactor(object):
         self._outgoingstream = stream(1)
         self._pendingrequests = collections.deque()
         self._activerequests = {}
+        self._incomingstreams = {}
 
     def callcommand(self, name, args, datafh=None):
         """Request that a command be executed.
@@ -1007,3 +1008,63 class clientreactor(object):
             yield frame
 
         request.state = 'sent'
+
+    def onframerecv(self, frame):
+        """Process a frame that has been received off the wire.
+
+        Returns a 2-tuple of (action, meta) describing further action the
+        caller needs to take as a result of receiving this frame.
+        """
+        if frame.streamid % 2:
+            return 'error', {
+                'message': (
+                    _('received frame with odd numbered stream ID: %d') %
+                    frame.streamid),
+            }
+
+        if frame.streamid not in self._incomingstreams:
+            if not frame.streamflags & STREAM_FLAG_BEGIN_STREAM:
+                return 'error', {
+                    'message': _('received frame on unknown stream '
+                                 'without beginning of stream flag set'),
+                }
+
+        if frame.streamflags & STREAM_FLAG_ENCODING_APPLIED:
+            raise error.ProgrammingError('support for decoding stream '
+                                         'payloads not yet implemneted')
+
+        if frame.streamflags & STREAM_FLAG_END_STREAM:
+            del self._incomingstreams[frame.streamid]
+
+        if frame.requestid not in self._activerequests:
+            return 'error', {
+                'message': (_('received frame for inactive request ID: %d') %
+                            frame.requestid),
+            }
+
+        request = self._activerequests[frame.requestid]
+        request.state = 'receiving'
+
+        handlers = {
+            FRAME_TYPE_BYTES_RESPONSE: self._onbytesresponseframe,
+        }
+
+        meth = handlers.get(frame.typeid)
+        if not meth:
+            raise error.ProgrammingError('unhandled frame type: %d' %
+                                         frame.typeid)
+
+        return meth(request, frame)
+
+    def _onbytesresponseframe(self, request, frame):
+        if frame.flags & FLAG_BYTES_RESPONSE_EOS:
+            request.state = 'received'
+            del self._activerequests[request.requestid]
+
+        return 'responsedata', {
+            'request': request,
+            'expectmore': frame.flags & FLAG_BYTES_RESPONSE_CONTINUATION,
+            'eos': frame.flags & FLAG_BYTES_RESPONSE_EOS,
+            'cbor': frame.flags & FLAG_BYTES_RESPONSE_CBOR,
+            'data': frame.payload,
+        }

tests/test-wireproto-clientreactor.py

@@ -7,6 +7,21 from mercurial import (
     wireprotoframing as framing,
 )
 
+ffs = framing.makeframefromhumanstring
+
+def sendframe(reactor, frame):
+    """Send a frame bytearray to a reactor."""
+    header = framing.parseheader(frame)
+    payload = frame[framing.FRAME_HEADER_SIZE:]
+    assert len(payload) == header.length
+
+    return reactor.onframerecv(framing.frame(header.requestid,
+                                             header.streamid,
+                                             header.streamflags,
+                                             header.typeid,
+                                             header.flags,
+                                             payload))
+
 class SingleSendTests(unittest.TestCase):
     """A reactor that can only send once rejects subsequent sends."""
     def testbasic(self):
@@ -61,6 +76,35 class NoBufferTests(unittest.TestCase):
 
         self.assertEqual(request.state, 'sent')
 
+class BadFrameRecvTests(unittest.TestCase):
+    def testoddstream(self):
+        reactor = framing.clientreactor()
+
+        action, meta = sendframe(reactor, ffs(b'1 1 0 1 0 foo'))
+        self.assertEqual(action, 'error')
+        self.assertEqual(meta['message'],
+                         'received frame with odd numbered stream ID: 1')
+
+    def testunknownstream(self):
+        reactor = framing.clientreactor()
+
+        action, meta = sendframe(reactor, ffs(b'1 0 0 1 0 foo'))
+        self.assertEqual(action, 'error')
+        self.assertEqual(meta['message'],
+                         'received frame on unknown stream without beginning '
+                         'of stream flag set')
+
+    def testunhandledframetype(self):
+        reactor = framing.clientreactor(buffersends=False)
+
+        request, action, meta = reactor.callcommand(b'foo', {})
+        for frame in meta['framegen']:
+            pass
+
+        with self.assertRaisesRegexp(error.ProgrammingError,
+                                     'unhandled frame type'):
+            sendframe(reactor, ffs(b'1 0 stream-begin text-output 0 foo'))
+
 if __name__ == '__main__':
     import silenttestrunner
     silenttestrunner.main(__name__)