Clean up types for PaginationConfig (#8250)

This removes `SourcePaginationConfig` and `get_pagination_rows`. The reasoning behind this is that these generic classes/functions erased the types of the IDs it used (i.e. instead of passing around `StreamToken` it'd pass in e.g. `token.room_key`, which don't have uniform types).

7 files changed, 52 insertions, 86 deletions

diff --git a/changelog.d/8250.misc b/changelog.d/8250.misc
new file mode 100644
index 0000000000..b6896a9300
--- /dev/null
+++ b/changelog.d/8250.misc
@@ -0,0 +1 @@
+Clean up type hints for `PaginationConfig`.
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index d5ddc583ad..ddb8f0712b 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -116,14 +116,13 @@ class InitialSyncHandler(BaseHandler):
         now_token = self.hs.get_event_sources().get_current_token()
 
         presence_stream = self.hs.get_event_sources().sources["presence"]
-        pagination_config = PaginationConfig(from_token=now_token)
-        presence, _ = await presence_stream.get_pagination_rows(
-            user, pagination_config.get_source_config("presence"), None
+        presence, _ = await presence_stream.get_new_events(
+            user, from_key=None, include_offline=False
         )
 
-        receipt_stream = self.hs.get_event_sources().sources["receipt"]
-        receipt, _ = await receipt_stream.get_pagination_rows(
-            user, pagination_config.get_source_config("receipt"), None
+        joined_rooms = [r.room_id for r in room_list if r.membership == Membership.JOIN]
+        receipt = await self.store.get_linearized_receipts_for_rooms(
+            joined_rooms, to_key=int(now_token.receipt_key),
         )
 
         tags_by_room = await self.store.get_tags_for_user(user_id)
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index 34ed0e2921..195a1fd77e 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -335,20 +335,16 @@ class PaginationHandler:
         user_id = requester.user.to_string()
 
         if pagin_config.from_token:
-            room_token = pagin_config.from_token.room_key
+            from_token = pagin_config.from_token
         else:
-            pagin_config.from_token = (
-                self.hs.get_event_sources().get_current_token_for_pagination()
-            )
-            room_token = pagin_config.from_token.room_key
-
-        room_token = RoomStreamToken.parse(room_token)
+            from_token = self.hs.get_event_sources().get_current_token_for_pagination()
 
-        pagin_config.from_token = pagin_config.from_token.copy_and_replace(
-            "room_key", str(room_token)
-        )
+        if pagin_config.limit is None:
+            # This shouldn't happen as we've set a default limit before this
+            # gets called.
+            raise Exception("limit not set")
 
-        source_config = pagin_config.get_source_config("room")
+        room_token = RoomStreamToken.parse(from_token.room_key)
 
         with await self.pagination_lock.read(room_id):
             (
@@ -358,7 +354,7 @@ class PaginationHandler:
                 room_id, user_id, allow_departed_users=True
             )
 
-            if source_config.direction == "b":
+            if pagin_config.direction == "b":
                 # if we're going backwards, we might need to backfill. This
                 # requires that we have a topo token.
                 if room_token.topological:
@@ -381,22 +377,28 @@ class PaginationHandler:
                         member_event_id
                     )
                     if RoomStreamToken.parse(leave_token).topological < max_topo:
-                        source_config.from_key = str(leave_token)
+                        from_token = from_token.copy_and_replace(
+                            "room_key", leave_token
+                        )
 
                 await self.hs.get_handlers().federation_handler.maybe_backfill(
                     room_id, max_topo
                 )
 
+            to_room_key = None
+            if pagin_config.to_token:
+                to_room_key = pagin_config.to_token.room_key
+
             events, next_key = await self.store.paginate_room_events(
                 room_id=room_id,
-                from_key=source_config.from_key,
-                to_key=source_config.to_key,
-                direction=source_config.direction,
-                limit=source_config.limit,
+                from_key=from_token.room_key,
+                to_key=to_room_key,
+                direction=pagin_config.direction,
+                limit=pagin_config.limit,
                 event_filter=event_filter,
             )
 
-            next_token = pagin_config.from_token.copy_and_replace("room_key", next_key)
+            next_token = from_token.copy_and_replace("room_key", next_key)
 
         if events:
             if event_filter:
@@ -409,7 +411,7 @@ class PaginationHandler:
         if not events:
             return {
                 "chunk": [],
-                "start": pagin_config.from_token.to_string(),
+                "start": from_token.to_string(),
                 "end": next_token.to_string(),
             }
 
@@ -438,7 +440,7 @@ class PaginationHandler:
                     events, time_now, as_client_event=as_client_event
                 )
             ),
-            "start": pagin_config.from_token.to_string(),
+            "start": from_token.to_string(),
             "end": next_token.to_string(),
         }
 
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 91a3aec1cc..1000ac95ff 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -1108,9 +1108,6 @@ class PresenceEventSource:
     def get_current_key(self):
         return self.store.get_current_presence_token()
 
-    async def get_pagination_rows(self, user, pagination_config, key):
-        return await self.get_new_events(user, from_key=None, include_offline=False)
-
     @cached(num_args=2, cache_context=True)
     async def _get_interested_in(self, user, explicit_room_id, cache_context):
         """Returns the set of users that the given user should see presence
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 2cc6c2eb68..bdd8e52edd 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -142,18 +142,3 @@ class ReceiptEventSource:
 
     def get_current_key(self, direction="f"):
         return self.store.get_max_receipt_stream_id()
-
-    async def get_pagination_rows(self, user, config, key):
-        to_key = int(config.from_key)
-
-        if config.to_key:
-            from_key = int(config.to_key)
-        else:
-            from_key = None
-
-        room_ids = await self.store.get_rooms_for_user(user.to_string())
-        events = await self.store.get_linearized_receipts_for_rooms(
-            room_ids, from_key=from_key, to_key=to_key
-        )
-
-        return (events, to_key)
diff --git a/synapse/notifier.py b/synapse/notifier.py
index b7f4041306..71f2370874 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -432,8 +432,9 @@ class Notifier:
         If explicit_room_id is set, that room will be polled for events only if
         it is world readable or the user has joined the room.
         """
-        from_token = pagination_config.from_token
-        if not from_token:
+        if pagination_config.from_token:
+            from_token = pagination_config.from_token
+        else:
             from_token = self.event_sources.get_current_token()
 
         limit = pagination_config.limit
diff --git a/synapse/streams/config.py b/synapse/streams/config.py
index d97dc4d101..0bdf846edf 100644
--- a/synapse/streams/config.py
+++ b/synapse/streams/config.py
@@ -14,9 +14,13 @@
 # limitations under the License.
 
 import logging
+from typing import Optional
+
+import attr
 
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import parse_integer, parse_string
+from synapse.http.site import SynapseRequest
 from synapse.types import StreamToken
 
 logger = logging.getLogger(__name__)
@@ -25,38 +29,22 @@ logger = logging.getLogger(__name__)
 MAX_LIMIT = 1000
 
 
-class SourcePaginationConfig:
-
-    """A configuration object which stores pagination parameters for a
-    specific event source."""
-
-    def __init__(self, from_key=None, to_key=None, direction="f", limit=None):
-        self.from_key = from_key
-        self.to_key = to_key
-        self.direction = "f" if direction == "f" else "b"
-        self.limit = min(int(limit), MAX_LIMIT) if limit is not None else None
-
-    def __repr__(self):
-        return "StreamConfig(from_key=%r, to_key=%r, direction=%r, limit=%r)" % (
-            self.from_key,
-            self.to_key,
-            self.direction,
-            self.limit,
-        )
-
-
+@attr.s(slots=True)
 class PaginationConfig:
-
     """A configuration object which stores pagination parameters."""
 
-    def __init__(self, from_token=None, to_token=None, direction="f", limit=None):
-        self.from_token = from_token
-        self.to_token = to_token
-        self.direction = "f" if direction == "f" else "b"
-        self.limit = min(int(limit), MAX_LIMIT) if limit is not None else None
+    from_token = attr.ib(type=Optional[StreamToken])
+    to_token = attr.ib(type=Optional[StreamToken])
+    direction = attr.ib(type=str)
+    limit = attr.ib(type=Optional[int])
 
     @classmethod
-    def from_request(cls, request, raise_invalid_params=True, default_limit=None):
+    def from_request(
+        cls,
+        request: SynapseRequest,
+        raise_invalid_params: bool = True,
+        default_limit: Optional[int] = None,
+    ) -> "PaginationConfig":
         direction = parse_string(request, "dir", default="f", allowed_values=["f", "b"])
 
         from_tok = parse_string(request, "from")
@@ -78,8 +66,11 @@ class PaginationConfig:
 
         limit = parse_integer(request, "limit", default=default_limit)
 
-        if limit and limit < 0:
-            raise SynapseError(400, "Limit must be 0 or above")
+        if limit:
+            if limit < 0:
+                raise SynapseError(400, "Limit must be 0 or above")
+
+            limit = min(int(limit), MAX_LIMIT)
 
         try:
             return PaginationConfig(from_tok, to_tok, direction, limit)
@@ -87,20 +78,10 @@ class PaginationConfig:
             logger.exception("Failed to create pagination config")
             raise SynapseError(400, "Invalid request.")
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return ("PaginationConfig(from_tok=%r, to_tok=%r, direction=%r, limit=%r)") % (
             self.from_token,
             self.to_token,
             self.direction,
             self.limit,
         )
-
-    def get_source_config(self, source_name):
-        keyname = "%s_key" % source_name
-
-        return SourcePaginationConfig(
-            from_key=getattr(self.from_token, keyname),
-            to_key=getattr(self.to_token, keyname) if self.to_token else None,
-            direction=self.direction,
-            limit=self.limit,
-        )