From 174b3242fcb6c60a052d20aa1996b6c68d82b7b3 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Wed, 30 Aug 2017 17:48:55 +0530
Subject: [PATCH] Support building Channels from existing handle, make .get()
 interruptible.

---
 econtext/core.py | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/econtext/core.py b/econtext/core.py
index 6026e424..b6202d38 100644
--- a/econtext/core.py
+++ b/econtext/core.py
@@ -176,11 +176,11 @@ class Message(object):
 
 
 class Channel(object):
-    def __init__(self, context, handle):
+    def __init__(self, context, handle=None):
         self._context = context
-        self._handle = handle
         self._queue = Queue.Queue()
-        self._context.add_handler(self._receive, handle)
+        self.handle = handle  # Avoid __repr__ crash in add_handler()
+        self.handle = context.add_handler(self._receive, handle)
 
     def _receive(self, msg):
         """Callback from the Stream; appends data to the internal queue."""
@@ -190,19 +190,27 @@ class Channel(object):
     def close(self):
         """Indicate this channel is closed to the remote side."""
         IOLOG.debug('%r.close()', self)
-        self._context.send(self._handle, _DEAD)
+        self._context.send(self.handle, _DEAD)
 
     def put(self, data):
         """Send `data` to the remote."""
         IOLOG.debug('%r.send(%r)', self, data)
-        self._context.send(self._handle, data)
+        self._context.send(self.handle, data)
 
     def get(self, timeout=None):
         """Receive an object, or ``None`` if `timeout` is reached."""
         IOLOG.debug('%r.on_receive(timeout=%r)', self, timeout)
-        try:
-            msg = self._queue.get(True, timeout)
-        except Queue.Empty:
+        if timeout:
+            timeout += time.time()
+
+        msg = None
+        while msg is None and (timeout is None or timeout < time.time()):
+            try:
+                msg = self._queue.get(True, 0.5)
+            except Queue.Empty:
+                continue
+
+        if msg is None:
             return
 
         IOLOG.debug('%r.on_receive() got %r', self, msg)
@@ -228,7 +236,7 @@ class Channel(object):
                 return
 
     def __repr__(self):
-        return 'Channel(%r, %r)' % (self._context, self._handle)
+        return 'Channel(%r, %r)' % (self._context, self.handle)
 
 
 class Importer(object):