Reuse existing pagination code for context API

This commit is contained in:
Erik Johnston 2018-05-08 16:19:33 +01:00
parent 3e6d306e94
commit 696f532453

View File

@ -42,7 +42,7 @@ from synapse.util.caches.descriptors import cached
from synapse.types import RoomStreamToken
from synapse.util.caches.stream_change_cache import StreamChangeCache
from synapse.util.logcontext import make_deferred_yieldable, run_in_background
from synapse.storage.engines import PostgresEngine, Sqlite3Engine
from synapse.storage.engines import PostgresEngine
import abc
import logging
@ -595,88 +595,28 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
retcols=["stream_ordering", "topological_ordering"],
)
token = RoomStreamToken(
# Paginating backwards includes the event at the token, but paginating
# forward doesn't.
before_token = RoomStreamToken(
results["topological_ordering"] - 1,
results["stream_ordering"],
)
after_token = RoomStreamToken(
results["topological_ordering"],
results["stream_ordering"],
)
if isinstance(self.database_engine, Sqlite3Engine):
# SQLite3 doesn't optimise ``(x < a) OR (x = a AND y < b)``
# So we give pass it to SQLite3 as the UNION ALL of the two queries.
query_before = (
"SELECT topological_ordering, stream_ordering, event_id FROM events"
" WHERE room_id = ? AND topological_ordering < ?"
" UNION ALL"
" SELECT topological_ordering, stream_ordering, event_id FROM events"
" WHERE room_id = ? AND topological_ordering = ? AND stream_ordering < ?"
" ORDER BY topological_ordering DESC, stream_ordering DESC LIMIT ?"
rows, start_token = self.paginate_room_events_txn(
txn, room_id, before_token, direction='b', limit=before_limit,
)
before_args = (
room_id, token.topological,
room_id, token.topological, token.stream,
before_limit,
)
query_after = (
"SELECT topological_ordering, stream_ordering, event_id FROM events"
" WHERE room_id = ? AND topological_ordering > ?"
" UNION ALL"
" SELECT topological_ordering, stream_ordering, event_id FROM events"
" WHERE room_id = ? AND topological_ordering = ? AND stream_ordering > ?"
" ORDER BY topological_ordering ASC, stream_ordering ASC LIMIT ?"
)
after_args = (
room_id, token.topological,
room_id, token.topological, token.stream,
after_limit,
)
else:
query_before = (
"SELECT topological_ordering, stream_ordering, event_id FROM events"
" WHERE room_id = ? AND %s"
" ORDER BY topological_ordering DESC, stream_ordering DESC LIMIT ?"
) % (upper_bound(token, self.database_engine, inclusive=False),)
before_args = (room_id, before_limit)
query_after = (
"SELECT topological_ordering, stream_ordering, event_id FROM events"
" WHERE room_id = ? AND %s"
" ORDER BY topological_ordering ASC, stream_ordering ASC LIMIT ?"
) % (lower_bound(token, self.database_engine, inclusive=False),)
after_args = (room_id, after_limit)
txn.execute(query_before, before_args)
rows = self.cursor_to_dict(txn)
events_before = [r["event_id"] for r in rows]
if rows:
start_token = str(RoomStreamToken(
rows[0]["topological_ordering"],
rows[0]["stream_ordering"] - 1,
))
else:
start_token = str(RoomStreamToken(
token.topological,
token.stream - 1,
))
txn.execute(query_after, after_args)
rows = self.cursor_to_dict(txn)
rows, end_token = self.paginate_room_events_txn(
txn, room_id, after_token, direction='f', limit=after_limit,
)
events_after = [r["event_id"] for r in rows]
if rows:
end_token = str(RoomStreamToken(
rows[-1]["topological_ordering"],
rows[-1]["stream_ordering"],
))
else:
end_token = str(token)
return {
"before": {
"event_ids": events_before,