split s2s into units

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

src/api/server/get_missing_events.rs

@@ -0,0 +1,86 @@
+use ruma::{
+	api::{client::error::ErrorKind, federation::event::get_missing_events},
+	OwnedEventId, RoomId,
+};
+
+use crate::{services, Error, PduEvent, Result, Ruma};
+
+/// # `POST /_matrix/federation/v1/get_missing_events/{roomId}`
+///
+/// Retrieves events that the sender is missing.
+pub(crate) async fn get_missing_events_route(
+	body: Ruma<get_missing_events::v1::Request>,
+) -> Result<get_missing_events::v1::Response> {
+	let origin = body.origin.as_ref().expect("server is authenticated");
+
+	if !services()
+		.rooms
+		.state_cache
+		.server_in_room(origin, &body.room_id)?
+	{
+		return Err(Error::BadRequest(ErrorKind::forbidden(), "Server is not in room"));
+	}
+
+	services()
+		.rooms
+		.event_handler
+		.acl_check(origin, &body.room_id)?;
+
+	let limit = body
+		.limit
+		.try_into()
+		.expect("UInt could not be converted to usize");
+
+	let mut queued_events = body.latest_events.clone();
+	// the vec will never have more entries the limit
+	let mut events = Vec::with_capacity(limit);
+
+	let mut i: usize = 0;
+	while i < queued_events.len() && events.len() < limit {
+		if let Some(pdu) = services().rooms.timeline.get_pdu_json(&queued_events[i])? {
+			let room_id_str = pdu
+				.get("room_id")
+				.and_then(|val| val.as_str())
+				.ok_or_else(|| Error::bad_database("Invalid event in database."))?;
+
+			let event_room_id = <&RoomId>::try_from(room_id_str)
+				.map_err(|_| Error::bad_database("Invalid room_id in event in database."))?;
+
+			if event_room_id != body.room_id {
+				return Err(Error::BadRequest(ErrorKind::InvalidParam, "Event from wrong room."));
+			}
+
+			if body.earliest_events.contains(&queued_events[i]) {
+				i = i.saturating_add(1);
+				continue;
+			}
+
+			if !services()
+				.rooms
+				.state_accessor
+				.server_can_see_event(origin, &body.room_id, &queued_events[i])?
+			{
+				i = i.saturating_add(1);
+				continue;
+			}
+
+			queued_events.extend_from_slice(
+				&serde_json::from_value::<Vec<OwnedEventId>>(
+					serde_json::to_value(
+						pdu.get("prev_events")
+							.cloned()
+							.ok_or_else(|| Error::bad_database("Event in db has no prev_events property."))?,
+					)
+					.expect("canonical json is valid json value"),
+				)
+				.map_err(|_| Error::bad_database("Invalid prev_events in event in database."))?,
+			);
+			events.push(PduEvent::convert_to_outgoing_federation_event(pdu));
+		}
+		i = i.saturating_add(1);
+	}
+
+	Ok(get_missing_events::v1::Response {
+		events,
+	})
+}