Call w.close() exactly once, in both success and error cases.

One downside is that we keep the wormhole channel allocated longer (we
have to finish the file transfer before we can deallocate it, which
could take a while for large files). Maybe we can fix this in the
future.

src/wormhole/cli/cmd_receive.py

@@ -1,7 +1,7 @@
 from __future__ import print_function
 import os, sys, json, binascii, six, tempfile, zipfile
 from tqdm import tqdm
-from twisted.internet import reactor, defer
+from twisted.internet import reactor
 from twisted.internet.defer import inlineCallbacks, returnValue
 from ..twisted.transcribe import Wormhole
 from ..twisted.transit import TransitReceiver
@@ -33,9 +33,8 @@ class TwistedReceiver:
     def msg(self, *args, **kwargs):
         print(*args, file=self.args.stdout, **kwargs)
 
-    # TODO: @handle_server_error
+    @inlineCallbacks
     def go(self):
-        d = defer.succeed(None)
         tor_manager = None
         if self.args.tor:
             _start = self.args.timing.add_event("import TorManager")
@@ -46,18 +45,10 @@ class TwistedReceiver:
             # tor in parallel with everything else, make sure the TorManager
             # can lazy-provide an endpoint, and overlap the startup process
             # with the user handing off the wormhole code
-            d.addCallback(lambda _: tor_manager.start())
+            yield tor_manager.start()
-        def _make_wormhole(_):
+        w = Wormhole(APPID, self.args.relay_url, tor_manager,
-            self._w = Wormhole(APPID, self.args.relay_url, tor_manager,
                      timing=self.args.timing,
                      reactor=self._reactor)
-        d.addCallback(_make_wormhole)
-        d.addCallback(lambda _: self._go(self._w, tor_manager))
-        def _always_close(res):
-            d2 = self._w.close()
-            d2.addBoth(lambda _: res)
-            return d2
-        d.addBoth(_always_close)
         # I wanted to do this instead:
         #
         #    try:
@@ -68,7 +59,9 @@ class TwistedReceiver:
         # but when _go had a UsageError, the stacktrace was always displayed
         # as coming from the "yield self._go" line, which wasn't very useful
         # for tracking it down.
-        return d
+        d = self._go(w, tor_manager)
+        d.addBoth(w.close)
+        yield d
 
     @inlineCallbacks
     def _go(self, w, tor_manager):

src/wormhole/cli/cmd_send.py

@@ -51,6 +51,13 @@ def send(args, reactor=reactor):
     w = Wormhole(APPID, args.relay_url, tor_manager, timing=args.timing,
                  reactor=reactor)
 
+    d = _send(reactor, w, args, phase1, fd_to_send, tor_manager)
+    d.addBoth(w.close)
+    yield d
+
+@inlineCallbacks
+def _send(reactor, w, args, phase1, fd_to_send, tor_manager):
+    transit_sender = None
     if fd_to_send:
         transit_sender = TransitSender(args.transit_helper,
                                        no_listen=args.no_listen,
@@ -103,7 +110,6 @@ def send(args, reactor=reactor):
     if fd_to_send is None:
         if them_phase1["message_ack"] == "ok":
             print(u"text message sent", file=args.stdout)
-            yield w.close()
             returnValue(None) # terminates this function
         raise TransferError("error sending text: %r" % (them_phase1,))
 
@@ -114,7 +120,9 @@ def send(args, reactor=reactor):
         raise TransferError("ambiguous response from remote, "
                             "transfer abandoned: %s" % (them_phase1,))
     tdata = them_phase1["transit"]
-    yield w.close()
+    # XXX the downside of closing above, rather than here, is that it leaves
+    # the channel claimed for a longer time
+    #yield w.close()
     yield _send_file_twisted(tdata, transit_sender, fd_to_send,
                              args.stdout, args.hide_progress, args.timing)
     returnValue(None)