split event_handler service

Signed-off-by: Jason Volk <jason@zemos.net>

src/service/rooms/event_handler/handle_prev_pdu.rs

@@ -0,0 +1,82 @@
+use std::{
+	collections::{BTreeMap, HashMap},
+	sync::Arc,
+	time::Instant,
+};
+
+use conduit::{debug, implement, utils::math::continue_exponential_backoff_secs, Error, PduEvent, Result};
+use ruma::{api::client::error::ErrorKind, CanonicalJsonValue, EventId, RoomId, ServerName};
+
+#[implement(super::Service)]
+#[allow(clippy::type_complexity)]
+#[allow(clippy::too_many_arguments)]
+#[tracing::instrument(
+	skip(self, origin, event_id, room_id, eventid_info, create_event, first_pdu_in_room),
+	name = "prev"
+)]
+pub(super) async fn handle_prev_pdu<'a>(
+	&self, origin: &'a ServerName, event_id: &'a EventId, room_id: &'a RoomId,
+	eventid_info: &mut HashMap<Arc<EventId>, (Arc<PduEvent>, BTreeMap<String, CanonicalJsonValue>)>,
+	create_event: &Arc<PduEvent>, first_pdu_in_room: &Arc<PduEvent>, prev_id: &EventId,
+) -> Result {
+	// Check for disabled again because it might have changed
+	if self.services.metadata.is_disabled(room_id).await {
+		debug!(
+			"Federaton of room {room_id} is currently disabled on this server. Request by origin {origin} and event \
+			 ID {event_id}"
+		);
+		return Err(Error::BadRequest(
+			ErrorKind::forbidden(),
+			"Federation of this room is currently disabled on this server.",
+		));
+	}
+
+	if let Some((time, tries)) = self
+		.services
+		.globals
+		.bad_event_ratelimiter
+		.read()
+		.expect("locked")
+		.get(prev_id)
+	{
+		// Exponential backoff
+		const MIN_DURATION: u64 = 5 * 60;
+		const MAX_DURATION: u64 = 60 * 60 * 24;
+		if continue_exponential_backoff_secs(MIN_DURATION, MAX_DURATION, time.elapsed(), *tries) {
+			debug!(
+				?tries,
+				duration = ?time.elapsed(),
+				"Backing off from prev_event"
+			);
+			return Ok(());
+		}
+	}
+
+	if let Some((pdu, json)) = eventid_info.remove(prev_id) {
+		// Skip old events
+		if pdu.origin_server_ts < first_pdu_in_room.origin_server_ts {
+			return Ok(());
+		}
+
+		let start_time = Instant::now();
+		self.federation_handletime
+			.write()
+			.expect("locked")
+			.insert(room_id.to_owned(), ((*prev_id).to_owned(), start_time));
+
+		self.upgrade_outlier_to_timeline_pdu(pdu, json, create_event, origin, room_id)
+			.await?;
+
+		self.federation_handletime
+			.write()
+			.expect("locked")
+			.remove(&room_id.to_owned());
+
+		debug!(
+			elapsed = ?start_time.elapsed(),
+			"Handled prev_event",
+		);
+	}
+
+	Ok(())
+}