style: Re-use GET_MISSING_EVENTS_MAX_BATCH_SIZE

src/api/server/get_missing_events.rs

@@ -4,15 +4,11 @@ use axum::extract::State;
 use conduwuit::{Err, Event, Result, debug, info, trace, utils::to_canonical_object, warn};
 use ruma::{OwnedEventId, api::federation::event::get_missing_events};
 use serde_json::{json, value::RawValue};
+use service::rooms::event_handler::GET_MISSING_EVENTS_MAX_BATCH_SIZE;
 
 use super::AccessCheck;
 use crate::Ruma;
 
-/// arbitrary number but synapse's is 20 and we can handle lots of these anyways
-const LIMIT_MAX: usize = 50;
-/// spec says default is 10
-const LIMIT_DEFAULT: usize = 10;
-
 /// # `POST /_matrix/federation/v1/get_missing_events/{roomId}`
 ///
 /// Retrieves events that the sender is missing.
@@ -45,8 +41,8 @@ pub(crate) async fn get_missing_events_route(
 	let limit = body
 		.limit
 		.try_into()
-		.unwrap_or(LIMIT_DEFAULT)
-		.min(LIMIT_MAX);
+		.unwrap_or(10)
+		.min(GET_MISSING_EVENTS_MAX_BATCH_SIZE);
 
 	let room_version = services.rooms.state.get_room_version(&body.room_id).await?;
 

src/service/rooms/event_handler/fetch_and_handle_outliers.rs

@@ -25,7 +25,7 @@ use ruma::{
 use super::get_room_version_rules;
 use crate::rooms::event_handler::parse_incoming_pdu::expect_event_id_array;
 
-const GET_MISSING_EVENTS_MAX_BATCH_SIZE: u16 = 50; // matches src/server/get_missing_events.rs#LIMIT_MAX
+pub const GET_MISSING_EVENTS_MAX_BATCH_SIZE: usize = 50;
 
 /// Attempts to build a localised directed acyclic graph out of the given PDUs,
 /// returning them in a topologically sorted order.
@@ -505,7 +505,9 @@ impl super::Service {
 			let limit = iteration
 				.expected_add(1)
 				.saturating_mul(10)
-				.min(GET_MISSING_EVENTS_MAX_BATCH_SIZE)
+				.min(GET_MISSING_EVENTS_MAX_BATCH_SIZE.try_into().expect(
+					"GET_MISSING_EVENTS_MAX_BATCH_SIZE (usize) should fit in u16 (<=65536)",
+				))
 				.max(
 					// This max call ensures we fetch *at least* all the prev events the
 					// head has.

src/service/rooms/event_handler/mod.rs

@@ -14,7 +14,7 @@ use std::{collections::HashMap, fmt::Write, sync::Arc, time::Instant};
 
 use async_trait::async_trait;
 use conduwuit::{Err, Event, PduEvent, Result, Server, SyncRwLock, utils::MutexMap};
-pub use fetch_and_handle_outliers::build_local_dag;
+pub use fetch_and_handle_outliers::{GET_MISSING_EVENTS_MAX_BATCH_SIZE, build_local_dag};
 use ruma::{
 	OwnedEventId, OwnedRoomId, RoomId, events::room::create::RoomCreateEventContent,
 	room_version_rules::RoomVersionRules,