make progress on rlcompleter, still broken

docs/api.md

@@ -232,7 +232,7 @@ helper to do tab completion of wormhole codes:
 ```python
 from wormhole import create, rlcompleter_helper
 w = create(appid, relay_url, reactor)
-rlcompleter_helper("Wormhole code:", w.input_code())
+rlcompleter_helper("Wormhole code:", w.input_code(), reactor)
 d = w.when_code()
 ```
 

src/wormhole/_code.py

@@ -5,6 +5,9 @@ from attr.validators import provides
 from automat import MethodicalMachine
 from . import _interfaces
 
+def first(outputs):
+    return list(outputs)[0]
+
 @attrs
 @implementer(_interfaces.ICode)
 class Code(object):
@@ -79,7 +82,7 @@ class Code(object):
 
     S0_idle.upon(set_code, enter=S4_known, outputs=[do_set_code])
     S0_idle.upon(input_code, enter=S1_inputting_nameplate,
-                 outputs=[do_start_input])
+                 outputs=[do_start_input], collector=first)
     S1_inputting_nameplate.upon(got_nameplate, enter=S2_inputting_words,
                                 outputs=[do_middle_input])
     S2_inputting_words.upon(finished_input, enter=S4_known,

src/wormhole/_rlcompleter.py

@@ -1,11 +1,12 @@
 from __future__ import print_function, unicode_literals
+import sys
 import six
 from attr import attrs, attrib
 from twisted.internet.defer import inlineCallbacks, returnValue
 from twisted.internet.threads import deferToThread, blockingCallFromThread
 
 @attrs
-class CodeInputter:
+class CodeInputter(object):
     _input_helper = attrib()
     _reactor = attrib()
     def __attrs_post_init__(self):
@@ -23,10 +24,14 @@ class CodeInputter:
             # completer exceptions are normally silently discarded, which
             # makes debugging challenging
             print("completer exception: %s" % e)
+            import traceback
+            traceback.print_exc()
             raise e
 
     def completer(self, text, state):
         self.used_completion = True
+        # debug
+        #import readline
         #if state == 0:
         #    print("", file=sys.stderr)
         #print("completer: '%s' %d '%d'" % (text, state,
@@ -68,10 +73,10 @@ class CodeInputter:
         #sys.stderr.flush()
         return self._matches[state]
 
-def input_code_with_completion(prompt, input_helper, code_length):
+def input_code_with_completion(prompt, input_helper, reactor):
     try:
         import readline
-        c = CodeInputter(input_helper)
+        c = CodeInputter(input_helper, reactor)
         if readline.__doc__ and "libedit" in readline.__doc__:
             readline.parse_and_bind("bind ^I rl_complete")
         else:
@@ -89,12 +94,45 @@ def input_code_with_completion(prompt, input_helper, code_length):
     used_completion = c.used_completion if c else False
     return (code, used_completion)
 
+def warn_readline():
+    # When our process receives a SIGINT, Twisted's SIGINT handler will
+    # stop the reactor and wait for all threads to terminate before the
+    # process exits. However, if we were waiting for
+    # input_code_with_completion() when SIGINT happened, the readline
+    # thread will be blocked waiting for something on stdin. Trick the
+    # user into satisfying the blocking read so we can exit.
+    print("\nCommand interrupted: please press Return to quit",
+          file=sys.stderr)
+
+    # Other potential approaches to this problem:
+    # * hard-terminate our process with os._exit(1), but make sure the
+    #   tty gets reset to a normal mode ("cooked"?) first, so that the
+    #   next shell command the user types is echoed correctly
+    # * track down the thread (t.p.threadable.getThreadID from inside the
+    #   thread), get a cffi binding to pthread_kill, deliver SIGINT to it
+    # * allocate a pty pair (pty.openpty), replace sys.stdin with the
+    #   slave, build a pty bridge that copies bytes (and other PTY
+    #   things) from the real stdin to the master, then close the slave
+    #   at shutdown, so readline sees EOF
+    # * write tab-completion and basic editing (TTY raw mode,
+    #   backspace-is-erase) without readline, probably with curses or
+    #   twisted.conch.insults
+    # * write a separate program to get codes (maybe just "wormhole
+    #   --internal-get-code"), run it as a subprocess, let it inherit
+    #   stdin/stdout, send it SIGINT when we receive SIGINT ourselves. It
+    #   needs an RPC mechanism (over some extra file descriptors) to ask
+    #   us to fetch the current nameplate_id list.
+    #
+    # Note that hard-terminating our process with os.kill(os.getpid(),
+    # signal.SIGKILL), or SIGTERM, doesn't seem to work: the thread
+    # doesn't see the signal, and we must still wait for stdin to make
+    # readline finish.
+
 @inlineCallbacks
 def rlcompleter_helper(prompt, input_helper, reactor):
-    def warn_readline():
-        pass
     t = reactor.addSystemEventTrigger("before", "shutdown", warn_readline)
-    res = yield deferToThread(input_code_with_completion, prompt, input_helper)
+    res = yield deferToThread(input_code_with_completion, prompt, input_helper,
+                              reactor)
     (code, used_completion) = res
     reactor.removeSystemEventTrigger(t)
     returnValue(used_completion)

src/wormhole/cli/cmd_receive.py

@@ -164,9 +164,13 @@ class TwistedReceiver:
         if code:
             w.set_code(code)
         else:
-            raise NotImplemented
+            from .._rlcompleter import rlcompleter_helper
-            yield w.input_code("Enter receive wormhole code: ", # TODO
+            used_completion = yield rlcompleter_helper("Enter receive wormhole code: ",
-                               self.args.code_length)
+                                                       w.input_code(),
+                                                       self._reactor)
+            if not used_completion:
+                print(" (note: you can use <Tab> to complete words)",
+                      file=self.args.stderr)
         yield w.when_code()
 
     def _show_verifier(self, verifier):