From d97efa0bd82daa54d4aca1a3996001d1b71634a7 Mon Sep 17 00:00:00 2001
From: mathieui <mathieui@mathieui.net>
Date: Fri, 23 Aug 2019 00:01:08 +0200
Subject: add a separate place for slow ass filters

---
 slixmpp/xmlstream/xmlstream.py | 41 +++++++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/slixmpp/xmlstream/xmlstream.py b/slixmpp/xmlstream/xmlstream.py
index 04d16c6b..7909318d 100644
--- a/slixmpp/xmlstream/xmlstream.py
+++ b/slixmpp/xmlstream/xmlstream.py
@@ -21,7 +21,7 @@ import ssl
 import weakref
 import uuid
 
-from asyncio import iscoroutinefunction
+from asyncio import iscoroutinefunction, wait
 
 import xml.etree.ElementTree as ET
 
@@ -896,6 +896,31 @@ class XMLStream(asyncio.BaseProtocol):
         """
         return xml
 
+    async def continue_slow_send(self, task, already_used):
+        log.debug('rescheduled task: %s', task)
+        data = await task
+        log.debug('data for rescheduled task %s : %s', task, data)
+        for filter in self.__filters['out']:
+            if filter in already_used:
+                continue
+            if iscoroutinefunction(filter):
+                data = await task
+            else:
+                data = filter(data)
+            if data is None:
+                return
+
+        if isinstance(data, ElementBase):
+            for filter in self.__filters['out_sync']:
+                data = filter(data)
+                if data is None:
+                    return
+            str_data = tostring(data.xml, xmlns=self.default_ns,
+                                stream=self, top_level=True)
+            self.send_raw(str_data)
+        else:
+            self.send_raw(data)
+
     async def run_filters(self):
         """
         Background loop that processes stanzas to send.
@@ -905,9 +930,16 @@ class XMLStream(asyncio.BaseProtocol):
             try:
                 if isinstance(data, ElementBase):
                     if use_filters:
+                        already_run_filters = set()
                         for filter in self.__filters['out']:
+                            already_run_filters.add(filter)
                             if iscoroutinefunction(filter):
-                                data = await filter(data)
+                                task = asyncio.create_task(filter(data))
+                                completed, pending = await wait({task}, timeout=1)
+                                if pending:
+                                    asyncio.ensure_future(self.continue_slow_send(task, already_run_filters))
+                                    raise Exception("Slow coro, rescheduling")
+                                data = task.result()
                             else:
                                 data = filter(data)
                             if data is None:
@@ -916,10 +948,7 @@ class XMLStream(asyncio.BaseProtocol):
                 if isinstance(data, ElementBase):
                     if use_filters:
                         for filter in self.__filters['out_sync']:
-                            if iscoroutinefunction(filter):
-                                data = await filter(data)
-                            else:
-                                data = filter(data)
+                            data = filter(data)
                             if data is None:
                                 raise Exception('Empty stanza')
                     str_data = tostring(data.xml, xmlns=self.default_ns,
-- 
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