typing: matchers and senders

Leftover error that I cannot fix:

* https://github.com/python/mypy/issues/708

Leftover error that I am unsure of what to do:

* xml handlers are not properly typed

(it seems like nothing in slix is using it, considering a removal
 instead of adding an Union everywhere)

14 files changed, 189 insertions, 105 deletions

diff --git a/slixmpp/xmlstream/handler/base.py b/slixmpp/xmlstream/handler/base.py
index 1e657777..e1edb249 100644
--- a/slixmpp/xmlstream/handler/base.py
+++ b/slixmpp/xmlstream/handler/base.py
@@ -4,10 +4,18 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
+from __future__ import annotations
+
 import weakref
+from weakref import ReferenceType
+from typing import Optional, TYPE_CHECKING
+from slixmpp.xmlstream.matcher.base import MatcherBase
+
+if TYPE_CHECKING:
+    from slixmpp.xmlstream import XMLStream, StanzaBase
 
 
-class BaseHandler(object):
+class BaseHandler:
 
     """
     Base class for stream handlers. Stream handlers are matched with
@@ -26,8 +34,13 @@ class BaseHandler(object):
     :param stream: The :class:`~slixmpp.xmlstream.xmlstream.XMLStream`
                     instance that the handle will respond to.
     """
+    name: str
+    stream: Optional[ReferenceType[XMLStream]]
+    _destroy: bool
+    _matcher: MatcherBase
+    _payload: Optional[StanzaBase]
 
-    def __init__(self, name, matcher, stream=None):
+    def __init__(self, name: str, matcher: MatcherBase, stream: Optional[XMLStream] = None):
         #: The name of the handler
         self.name = name
 
@@ -41,33 +54,33 @@ class BaseHandler(object):
         self._payload = None
         self._matcher = matcher
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """Compare a stanza or XML object with the handler's matcher.
 
         :param xml: An XML or
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object
         """
         return self._matcher.match(xml)
 
-    def prerun(self, payload):
+    def prerun(self, payload: StanzaBase) -> None:
         """Prepare the handler for execution while the XML
         stream is being processed.
 
-        :param payload: A :class:`~slixmpp.xmlstream.stanzabase.ElementBase`
+        :param payload: A :class:`~slixmpp.xmlstream.stanzabase.StanzaBase`
                         object.
         """
         self._payload = payload
 
-    def run(self, payload):
+    def run(self, payload: StanzaBase) -> None:
         """Execute the handler after XML stream processing and during the
         main event loop.
 
-        :param payload: A :class:`~slixmpp.xmlstream.stanzabase.ElementBase`
+        :param payload: A :class:`~slixmpp.xmlstream.stanzabase.StanzaBase`
                         object.
         """
         self._payload = payload
 
-    def check_delete(self):
+    def check_delete(self) -> bool:
         """Check if the handler should be removed from the list
         of stream handlers.
         """
diff --git a/slixmpp/xmlstream/handler/callback.py b/slixmpp/xmlstream/handler/callback.py
index 93cec6b7..5d792bf9 100644
--- a/slixmpp/xmlstream/handler/callback.py
+++ b/slixmpp/xmlstream/handler/callback.py
@@ -1,10 +1,17 @@
-
 # slixmpp.xmlstream.handler.callback
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
+from __future__ import annotations
+
+from typing import Optional, Callable, Any, TYPE_CHECKING
 from slixmpp.xmlstream.handler.base import BaseHandler
+from slixmpp.xmlstream.matcher.base import MatcherBase
+
+if TYPE_CHECKING:
+    from slixmpp.xmlstream.stanzabase import StanzaBase
+    from slixmpp.xmlstream.xmlstream import XMLStream
 
 
 class Callback(BaseHandler):
@@ -28,8 +35,6 @@ class Callback(BaseHandler):
     :param matcher: A :class:`~slixmpp.xmlstream.matcher.base.MatcherBase`
                     derived object for matching stanza objects.
     :param pointer: The function to execute during callback.
-    :param bool thread: **DEPRECATED.** Remains only for
-                        backwards compatibility.
     :param bool once: Indicates if the handler should be used only
                       once. Defaults to False.
     :param bool instream: Indicates if the callback should be executed
@@ -38,31 +43,36 @@ class Callback(BaseHandler):
     :param stream: The :class:`~slixmpp.xmlstream.xmlstream.XMLStream`
                    instance this handler should monitor.
     """
+    _once: bool
+    _instream: bool
+    _pointer: Callable[[StanzaBase], Any]
 
-    def __init__(self, name, matcher, pointer, thread=False,
-                 once=False, instream=False, stream=None):
+    def __init__(self, name: str, matcher: MatcherBase,
+                 pointer: Callable[[StanzaBase], Any],
+                 once: bool = False, instream: bool = False,
+                 stream: Optional[XMLStream] = None):
         BaseHandler.__init__(self, name, matcher, stream)
         self._pointer = pointer
         self._once = once
         self._instream = instream
 
-    def prerun(self, payload):
+    def prerun(self, payload: StanzaBase) -> None:
         """Execute the callback during stream processing, if
         the callback was created with ``instream=True``.
 
         :param payload: The matched
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object.
         """
         if self._once:
             self._destroy = True
         if self._instream:
             self.run(payload, True)
 
-    def run(self, payload, instream=False):
+    def run(self, payload: StanzaBase, instream: bool = False) -> None:
         """Execute the callback function with the matched stanza payload.
 
         :param payload: The matched
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object.
         :param bool instream: Force the handler to execute during stream
                               processing. This should only be used by
                               :meth:`prerun()`. Defaults to ``False``.
diff --git a/slixmpp/xmlstream/handler/collector.py b/slixmpp/xmlstream/handler/collector.py
index 8d012873..a5ee109c 100644
--- a/slixmpp/xmlstream/handler/collector.py
+++ b/slixmpp/xmlstream/handler/collector.py
@@ -4,11 +4,17 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2012 Nathanael C. Fritz, Lance J.T. Stout
 # :license: MIT, see LICENSE for more details
+from __future__ import annotations
+
 import logging
-from queue import Queue, Empty
+from typing import List, Optional, TYPE_CHECKING
 
+from slixmpp.xmlstream.stanzabase import StanzaBase
 from slixmpp.xmlstream.handler.base import BaseHandler
+from slixmpp.xmlstream.matcher.base import MatcherBase
 
+if TYPE_CHECKING:
+    from slixmpp.xmlstream.xmlstream import XMLStream
 
 log = logging.getLogger(__name__)
 
@@ -27,35 +33,35 @@ class Collector(BaseHandler):
     :param stream: The :class:`~slixmpp.xmlstream.xmlstream.XMLStream`
                    instance this handler should monitor.
     """
+    _stanzas: List[StanzaBase]
 
-    def __init__(self, name, matcher, stream=None):
+    def __init__(self, name: str, matcher: MatcherBase, stream: Optional[XMLStream] = None):
         BaseHandler.__init__(self, name, matcher, stream=stream)
-        self._payload = Queue()
+        self._stanzas = []
 
-    def prerun(self, payload):
+    def prerun(self, payload: StanzaBase) -> None:
         """Store the matched stanza when received during processing.
 
         :param payload: The matched
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object.
         """
-        self._payload.put(payload)
+        self._stanzas.append(payload)
 
-    def run(self, payload):
+    def run(self, payload: StanzaBase) -> None:
         """Do not process this handler during the main event loop."""
         pass
 
-    def stop(self):
+    def stop(self) -> List[StanzaBase]:
         """
         Stop collection of matching stanzas, and return the ones that
         have been stored so far.
         """
+        stream_ref = self.stream
+        if stream_ref is None:
+            raise ValueError('stop() called without a stream!')
+        stream = stream_ref()
+        if stream is None:
+            raise ValueError('stop() called without a stream!')
         self._destroy = True
-        results = []
-        try:
-            while True:
-                results.append(self._payload.get(False))
-        except Empty:
-            pass
-
-        self.stream().remove_handler(self.name)
-        return results
+        stream.remove_handler(self.name)
+        return self._stanzas
diff --git a/slixmpp/xmlstream/handler/coroutine_callback.py b/slixmpp/xmlstream/handler/coroutine_callback.py
index 6568ba9f..d41cd7ba 100644
--- a/slixmpp/xmlstream/handler/coroutine_callback.py
+++ b/slixmpp/xmlstream/handler/coroutine_callback.py
@@ -4,8 +4,19 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
+from __future__ import annotations
+
+from asyncio import iscoroutinefunction, ensure_future
+from typing import Optional, Callable, Awaitable, TYPE_CHECKING
+
+from slixmpp.xmlstream.stanzabase import StanzaBase
 from slixmpp.xmlstream.handler.base import BaseHandler
-from slixmpp.xmlstream.asyncio import asyncio
+from slixmpp.xmlstream.matcher.base import MatcherBase
+
+CoroutineFunction = Callable[[StanzaBase], Awaitable[None]]
+
+if TYPE_CHECKING:
+    from slixmpp.xmlstream.xmlstream import XMLStream
 
 
 class CoroutineCallback(BaseHandler):
@@ -34,15 +45,20 @@ class CoroutineCallback(BaseHandler):
                    instance this handler should monitor.
     """
 
-    def __init__(self, name, matcher, pointer, once=False,
-                 instream=False, stream=None):
+    _once: bool
+    _instream: bool
+    _pointer: CoroutineFunction
+
+    def __init__(self, name: str, matcher: MatcherBase,
+                 pointer: CoroutineFunction, once: bool = False,
+                 instream: bool = False, stream: Optional[XMLStream] = None):
         BaseHandler.__init__(self, name, matcher, stream)
-        if not asyncio.iscoroutinefunction(pointer):
+        if not iscoroutinefunction(pointer):
             raise ValueError("Given function is not a coroutine")
 
-        async def pointer_wrapper(stanza, *args, **kwargs):
+        async def pointer_wrapper(stanza: StanzaBase) -> None:
             try:
-                await pointer(stanza, *args, **kwargs)
+                await pointer(stanza)
             except Exception as e:
                 stanza.exception(e)
 
@@ -50,29 +66,29 @@ class CoroutineCallback(BaseHandler):
         self._once = once
         self._instream = instream
 
-    def prerun(self, payload):
+    def prerun(self, payload: StanzaBase) -> None:
         """Execute the callback during stream processing, if
         the callback was created with ``instream=True``.
 
         :param payload: The matched
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object.
         """
         if self._once:
             self._destroy = True
         if self._instream:
             self.run(payload, True)
 
-    def run(self, payload, instream=False):
+    def run(self, payload: StanzaBase, instream: bool = False) -> None:
         """Execute the callback function with the matched stanza payload.
 
         :param payload: The matched
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object.
         :param bool instream: Force the handler to execute during stream
                               processing. This should only be used by
                               :meth:`prerun()`. Defaults to ``False``.
         """
         if not self._instream or instream:
-            asyncio.ensure_future(self._pointer(payload))
+            ensure_future(self._pointer(payload))
             if self._once:
                 self._destroy = True
                 del self._pointer
diff --git a/slixmpp/xmlstream/handler/waiter.py b/slixmpp/xmlstream/handler/waiter.py
index 758cd1f1..684bd32f 100644
--- a/slixmpp/xmlstream/handler/waiter.py
+++ b/slixmpp/xmlstream/handler/waiter.py
@@ -4,13 +4,19 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
+from __future__ import annotations
+
 import logging
-import asyncio
-from  asyncio import Queue, wait_for, TimeoutError
+from asyncio import Event, wait_for, TimeoutError
+from typing import Optional, TYPE_CHECKING
 
 import slixmpp
+from slixmpp.xmlstream.stanzabase import StanzaBase
 from slixmpp.xmlstream.handler.base import BaseHandler
+from slixmpp.xmlstream.matcher.base import MatcherBase
 
+if TYPE_CHECKING:
+    from slixmpp.xmlstream.xmlstream import XMLStream
 
 log = logging.getLogger(__name__)
 
@@ -28,24 +34,27 @@ class Waiter(BaseHandler):
     :param stream: The :class:`~slixmpp.xmlstream.xmlstream.XMLStream`
                    instance this handler should monitor.
     """
+    _event: Event
 
-    def __init__(self, name, matcher, stream=None):
+    def __init__(self, name: str, matcher: MatcherBase, stream: Optional[XMLStream] = None):
         BaseHandler.__init__(self, name, matcher, stream=stream)
-        self._payload = Queue()
+        self._event = Event()
 
-    def prerun(self, payload):
+    def prerun(self, payload: StanzaBase) -> None:
         """Store the matched stanza when received during processing.
 
         :param payload: The matched
-            :class:`~slixmpp.xmlstream.stanzabase.ElementBase` object.
+            :class:`~slixmpp.xmlstream.stanzabase.StanzaBase` object.
         """
-        self._payload.put_nowait(payload)
+        if not self._event.is_set():
+            self._event.set()
+            self._payload = payload
 
-    def run(self, payload):
+    def run(self, payload: StanzaBase) -> None:
         """Do not process this handler during the main event loop."""
         pass
 
-    async def wait(self, timeout=None):
+    async def wait(self, timeout: Optional[int] = None) -> Optional[StanzaBase]:
         """Block an event handler while waiting for a stanza to arrive.
 
         Be aware that this will impact performance if called from a
@@ -59,17 +68,24 @@ class Waiter(BaseHandler):
             :class:`~slixmpp.xmlstream.xmlstream.XMLStream.response_timeout`
             value.
         """
+        stream_ref = self.stream
+        if stream_ref is None:
+            raise ValueError('wait() called without a stream')
+        stream = stream_ref()
+        if stream is None:
+            raise ValueError('wait() called without a stream')
         if timeout is None:
             timeout = slixmpp.xmlstream.RESPONSE_TIMEOUT
 
-        stanza = None
         try:
-            stanza = await self._payload.get()
+            await wait_for(
+                self._event.wait(), timeout, loop=stream.loop
+            )
         except TimeoutError:
             log.warning("Timed out waiting for %s", self.name)
-        self.stream().remove_handler(self.name)
-        return stanza
+        stream.remove_handler(self.name)
+        return self._payload
 
-    def check_delete(self):
+    def check_delete(self) -> bool:
         """Always remove waiters after use."""
         return True
diff --git a/slixmpp/xmlstream/handler/xmlcallback.py b/slixmpp/xmlstream/handler/xmlcallback.py
index b44b2da1..31534033 100644
--- a/slixmpp/xmlstream/handler/xmlcallback.py
+++ b/slixmpp/xmlstream/handler/xmlcallback.py
@@ -4,6 +4,7 @@
 # This file is part of Slixmpp.
 # See the file LICENSE for copying permission.
 from slixmpp.xmlstream.handler import Callback
+from slixmpp.xmlstream.stanzabase import StanzaBase
 
 
 class XMLCallback(Callback):
@@ -17,7 +18,7 @@ class XMLCallback(Callback):
         run -- Overrides Callback.run
     """
 
-    def run(self, payload, instream=False):
+    def run(self, payload: StanzaBase, instream: bool = False) -> None:
         """
         Execute the callback function with the matched stanza's
         XML contents, instead of the stanza itself.
diff --git a/slixmpp/xmlstream/handler/xmlwaiter.py b/slixmpp/xmlstream/handler/xmlwaiter.py
index 6eb6577e..65185a5f 100644
--- a/slixmpp/xmlstream/handler/xmlwaiter.py
+++ b/slixmpp/xmlstream/handler/xmlwaiter.py
@@ -3,6 +3,7 @@
 # Copyright (C) 2010  Nathanael C. Fritz
 # This file is part of Slixmpp.
 # See the file LICENSE for copying permission.
+from slixmpp.xmlstream.stanzabase import StanzaBase
 from slixmpp.xmlstream.handler import Waiter
 
 
@@ -17,7 +18,7 @@ class XMLWaiter(Waiter):
         prerun -- Overrides Waiter.prerun
     """
 
-    def prerun(self, payload):
+    def prerun(self, payload: StanzaBase) -> None:
         """
         Store the XML contents of the stanza to return to the
         waiting event handler.
diff --git a/slixmpp/xmlstream/matcher/base.py b/slixmpp/xmlstream/matcher/base.py
index e2560d2b..552269c5 100644
--- a/slixmpp/xmlstream/matcher/base.py
+++ b/slixmpp/xmlstream/matcher/base.py
@@ -1,10 +1,13 @@
-
 # slixmpp.xmlstream.matcher.base
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
 
+from typing import Any
+from slixmpp.xmlstream.stanzabase import StanzaBase
+
+
 class MatcherBase(object):
 
     """
@@ -15,10 +18,10 @@ class MatcherBase(object):
     :param criteria: Object to compare some aspect of a stanza against.
     """
 
-    def __init__(self, criteria):
+    def __init__(self, criteria: Any):
         self._criteria = criteria
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """Check if a stanza matches the stored criteria.
 
         Meant to be overridden.
diff --git a/slixmpp/xmlstream/matcher/id.py b/slixmpp/xmlstream/matcher/id.py
index 44df2c18..e4e7ad4e 100644
--- a/slixmpp/xmlstream/matcher/id.py
+++ b/slixmpp/xmlstream/matcher/id.py
@@ -5,6 +5,7 @@
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
 from slixmpp.xmlstream.matcher.base import MatcherBase
+from slixmpp.xmlstream.stanzabase import StanzaBase
 
 
 class MatcherId(MatcherBase):
@@ -13,12 +14,13 @@ class MatcherId(MatcherBase):
     The ID matcher selects stanzas that have the same stanza 'id'
     interface value as the desired ID.
     """
+    _criteria: str
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """Compare the given stanza's ``'id'`` attribute to the stored
         ``id`` value.
 
-        :param xml: The :class:`~slixmpp.xmlstream.stanzabase.ElementBase`
+        :param xml: The :class:`~slixmpp.xmlstream.stanzabase.StanzaBase`
                     stanza to compare against.
         """
-        return xml['id'] == self._criteria
+        return bool(xml['id'] == self._criteria)
diff --git a/slixmpp/xmlstream/matcher/idsender.py b/slixmpp/xmlstream/matcher/idsender.py
index 8f5d0303..9b12623d 100644
--- a/slixmpp/xmlstream/matcher/idsender.py
+++ b/slixmpp/xmlstream/matcher/idsender.py
@@ -4,7 +4,17 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
+
 from slixmpp.xmlstream.matcher.base import MatcherBase
+from slixmpp.xmlstream.stanzabase import StanzaBase
+from slixmpp.jid import JID
+from slixmpp.types import TypedDict
+
+
+class CriteriaType(TypedDict):
+    self: JID
+    peer: JID
+    id: str
 
 
 class MatchIDSender(MatcherBase):
@@ -14,12 +24,13 @@ class MatchIDSender(MatcherBase):
     interface value as the desired ID, and that the 'from' value is one
     of a set of approved entities that can respond to a request.
     """
+    _criteria: CriteriaType
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """Compare the given stanza's ``'id'`` attribute to the stored
         ``id`` value, and verify the sender's JID.
 
-        :param xml: The :class:`~slixmpp.xmlstream.stanzabase.ElementBase`
+        :param xml: The :class:`~slixmpp.xmlstream.stanzabase.StanzaBase`
                     stanza to compare against.
         """
 
diff --git a/slixmpp/xmlstream/matcher/many.py b/slixmpp/xmlstream/matcher/many.py
index e8ad54e7..dae45463 100644
--- a/slixmpp/xmlstream/matcher/many.py
+++ b/slixmpp/xmlstream/matcher/many.py
@@ -3,7 +3,9 @@
 # Copyright (C) 2010  Nathanael C. Fritz
 # This file is part of Slixmpp.
 # See the file LICENSE for copying permission.
+from typing import Iterable
 from slixmpp.xmlstream.matcher.base import MatcherBase
+from slixmpp.xmlstream.stanzabase import StanzaBase
 
 
 class MatchMany(MatcherBase):
@@ -18,8 +20,9 @@ class MatchMany(MatcherBase):
     Methods:
         match -- Overrides MatcherBase.match.
     """
+    _criteria: Iterable[MatcherBase]
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """
         Match a stanza against multiple criteria. The match is successful
         if one of the criteria matches.
diff --git a/slixmpp/xmlstream/matcher/stanzapath.py b/slixmpp/xmlstream/matcher/stanzapath.py
index 1bf3fa8e..b7de3ee2 100644
--- a/slixmpp/xmlstream/matcher/stanzapath.py
+++ b/slixmpp/xmlstream/matcher/stanzapath.py
@@ -4,8 +4,9 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
+from typing import cast, List
 from slixmpp.xmlstream.matcher.base import MatcherBase
-from slixmpp.xmlstream.stanzabase import fix_ns
+from slixmpp.xmlstream.stanzabase import fix_ns, StanzaBase
 
 
 class StanzaPath(MatcherBase):
@@ -17,22 +18,28 @@ class StanzaPath(MatcherBase):
 
     :param criteria: Object to compare some aspect of a stanza against.
     """
-
-    def __init__(self, criteria):
-        self._criteria = fix_ns(criteria, split=True,
-                                          propagate_ns=False,
-                                          default_ns='jabber:client')
+    _criteria: List[str]
+    _raw_criteria: str
+
+    def __init__(self, criteria: str):
+        self._criteria = cast(
+            List[str],
+            fix_ns(
+                criteria, split=True, propagate_ns=False,
+                default_ns='jabber:client'
+            )
+        )
         self._raw_criteria = criteria
 
-    def match(self, stanza):
+    def match(self, stanza: StanzaBase) -> bool:
         """
         Compare a stanza against a "stanza path". A stanza path is similar to
         an XPath expression, but uses the stanza's interfaces and plugins
         instead of the underlying XML. See the documentation for the stanza
-        :meth:`~slixmpp.xmlstream.stanzabase.ElementBase.match()` method
+        :meth:`~slixmpp.xmlstream.stanzabase.StanzaBase.match()` method
         for more information.
 
-        :param stanza: The :class:`~slixmpp.xmlstream.stanzabase.ElementBase`
+        :param stanza: The :class:`~slixmpp.xmlstream.stanzabase.StanzaBase`
                        stanza to compare against.
         """
         return stanza.match(self._criteria) or stanza.match(self._raw_criteria)
diff --git a/slixmpp/xmlstream/matcher/xmlmask.py b/slixmpp/xmlstream/matcher/xmlmask.py
index d50b706e..b63e0f05 100644
--- a/slixmpp/xmlstream/matcher/xmlmask.py
+++ b/slixmpp/xmlstream/matcher/xmlmask.py
@@ -1,4 +1,3 @@
-
 # Slixmpp: The Slick XMPP Library
 # Copyright (C) 2010  Nathanael C. Fritz
 # This file is part of Slixmpp.
@@ -6,8 +5,9 @@
 import logging
 
 from xml.parsers.expat import ExpatError
+from xml.etree.ElementTree import Element
 
-from slixmpp.xmlstream.stanzabase import ET
+from slixmpp.xmlstream.stanzabase import ET, StanzaBase
 from slixmpp.xmlstream.matcher.base import MatcherBase
 
 
@@ -33,32 +33,33 @@ class MatchXMLMask(MatcherBase):
     :param criteria: Either an :class:`~xml.etree.ElementTree.Element` XML
                      object or XML string to use as a mask.
     """
+    _criteria: Element
 
-    def __init__(self, criteria, default_ns='jabber:client'):
+    def __init__(self, criteria: str, default_ns: str = 'jabber:client'):
         MatcherBase.__init__(self, criteria)
         if isinstance(criteria, str):
-            self._criteria = ET.fromstring(self._criteria)
+            self._criteria = ET.fromstring(criteria)
         self.default_ns = default_ns
 
-    def setDefaultNS(self, ns):
+    def setDefaultNS(self, ns: str) -> None:
         """Set the default namespace to use during comparisons.
 
         :param ns: The new namespace to use as the default.
         """
         self.default_ns = ns
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """Compare a stanza object or XML object against the stored XML mask.
 
         Overrides MatcherBase.match.
 
         :param xml: The stanza object or XML object to compare against.
         """
-        if hasattr(xml, 'xml'):
-            xml = xml.xml
-        return self._mask_cmp(xml, self._criteria, True)
+        real_xml = xml.xml
+        return self._mask_cmp(real_xml, self._criteria, True)
 
-    def _mask_cmp(self, source, mask, use_ns=False, default_ns='__no_ns__'):
+    def _mask_cmp(self, source: Element, mask: Element, use_ns: bool = False,
+                  default_ns: str = '__no_ns__') -> bool:
         """Compare an XML object against an XML mask.
 
         :param source: The :class:`~xml.etree.ElementTree.Element` XML object
@@ -75,13 +76,6 @@ class MatchXMLMask(MatcherBase):
             # If the element was not found. May happen during recursive calls.
             return False
 
-        # Convert the mask to an XML object if it is a string.
-        if not hasattr(mask, 'attrib'):
-            try:
-                mask = ET.fromstring(mask)
-            except ExpatError:
-                log.warning("Expat error: %s\nIn parsing: %s", '', mask)
-
         mask_ns_tag = "{%s}%s" % (self.default_ns, mask.tag)
         if source.tag not in [mask.tag, mask_ns_tag]:
             return False
diff --git a/slixmpp/xmlstream/matcher/xpath.py b/slixmpp/xmlstream/matcher/xpath.py
index b7503b73..bd41b60a 100644
--- a/slixmpp/xmlstream/matcher/xpath.py
+++ b/slixmpp/xmlstream/matcher/xpath.py
@@ -4,7 +4,8 @@
 # Part of Slixmpp: The Slick XMPP Library
 # :copyright: (c) 2011 Nathanael C. Fritz
 # :license: MIT, see LICENSE for more details
-from slixmpp.xmlstream.stanzabase import ET, fix_ns
+from typing import cast
+from slixmpp.xmlstream.stanzabase import ET, fix_ns, StanzaBase
 from slixmpp.xmlstream.matcher.base import MatcherBase
 
 
@@ -17,23 +18,23 @@ class MatchXPath(MatcherBase):
     If the value of :data:`IGNORE_NS` is set to ``True``, then XPath
     expressions will be matched without using namespaces.
     """
+    _criteria: str
 
-    def __init__(self, criteria):
-        self._criteria = fix_ns(criteria)
+    def __init__(self, criteria: str):
+        self._criteria = cast(str, fix_ns(criteria))
 
-    def match(self, xml):
+    def match(self, xml: StanzaBase) -> bool:
         """
         Compare a stanza's XML contents to an XPath expression.
 
         If the value of :data:`IGNORE_NS` is set to ``True``, then XPath
         expressions will be matched without using namespaces.
 
-        :param xml: The :class:`~slixmpp.xmlstream.stanzabase.ElementBase`
+        :param xml: The :class:`~slixmpp.xmlstream.stanzabase.StanzaBase`
                     stanza to compare against.
         """
-        if hasattr(xml, 'xml'):
-            xml = xml.xml
+        real_xml = xml.xml
         x = ET.Element('x')
-        x.append(xml)
+        x.append(real_xml)
 
         return x.find(self._criteria) is not None