1 files changed, 83 insertions, 0 deletions
diff --git a/slixmpp/xmlstream/handler/waiter.py b/slixmpp/xmlstream/handler/waiter.py
new file mode 100644
index 00000000..c25063db
--- /dev/null
+++ b/slixmpp/xmlstream/handler/waiter.py
@@ -0,0 +1,83 @@
+# -*- coding: utf-8 -*-
+"""
+    slixmpp.xmlstream.handler.waiter
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Part of Slixmpp: The Slick XMPP Library
+
+    :copyright: (c) 2011 Nathanael C. Fritz
+    :license: MIT, see LICENSE for more details
+"""
+
+import logging
+from queue import Queue, Empty
+
+from slixmpp.xmlstream.handler.base import BaseHandler
+
+
+log = logging.getLogger(__name__)
+
+
+class Waiter(BaseHandler):
+
+    """
+    The Waiter handler allows an event handler to block until a
+    particular stanza has been received. The handler will either be
+    given the matched stanza, or ``False`` if the waiter has timed out.
+
+    :param string name: The name of the handler.
+    :param matcher: A :class:`~slixmpp.xmlstream.matcher.base.MatcherBase`
+                    derived object for matching stanza objects.
+    :param stream: The :class:`~slixmpp.xmlstream.xmlstream.XMLStream`
+                   instance this handler should monitor.
+    """
+
+    def __init__(self, name, matcher, stream=None):
+        BaseHandler.__init__(self, name, matcher, stream=stream)
+        self._payload = Queue()
+
+    def prerun(self, payload):
+        """Store the matched stanza when received during processing.
+
+        :param payload: The matched
+            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+        """
+        self._payload.put(payload)
+
+    def run(self, payload):
+        """Do not process this handler during the main event loop."""
+        pass
+
+    def wait(self, timeout=None):
+        """Block an event handler while waiting for a stanza to arrive.
+
+        Be aware that this will impact performance if called from a
+        non-threaded event handler.
+
+        Will return either the received stanza, or ``False`` if the
+        waiter timed out.
+
+        :param int timeout: The number of seconds to wait for the stanza
+            to arrive. Defaults to the the stream's
+            :class:`~slixmpp.xmlstream.xmlstream.XMLStream.response_timeout`
+            value.
+        """
+        if timeout is None:
+            timeout = self.stream().response_timeout
+
+        elapsed_time = 0
+        stanza = False
+        while elapsed_time < timeout and not self.stream().stop.is_set():
+            try:
+                stanza = self._payload.get(True, 1)
+                break
+            except Empty:
+                elapsed_time += 1
+                if elapsed_time >= timeout:
+                    log.warning("Timed out waiting for %s", self.name)
+        self.stream().remove_handler(self.name)
+        return stanza
+
+    def check_delete(self):
+        """Always remove waiters after use."""
+        return True