Support v1/v2 prev_events/auth_events outgoing federation format. (#12)

Support v1/v2 prev_events/auth_events when handling outlier pdu. (#12)

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

src/core/matrix/pdu/format.rs

@@ -1,6 +1,12 @@
-use ruma::{CanonicalJsonObject, CanonicalJsonValue, RoomVersionId};
+use ruma::{
+	CanonicalJsonObject, CanonicalJsonValue, EventId, RoomVersionId,
+	room_version_rules::{EventsReferenceFormatVersion, RoomVersionRules},
+};
 
-use crate::{is_equal_to, matrix::room_version};
+use crate::{
+	Result, err, extract_variant, is_equal_to,
+	matrix::{PduEvent, room_version},
+};
 
 pub fn into_outgoing_federation(
 	mut pdu_json: CanonicalJsonObject,
@@ -35,5 +41,67 @@ pub fn into_outgoing_federation(
 		}
 	}
 
+	if matches!(room_rules.events_reference_format, EventsReferenceFormatVersion::V1) {
+		if let Some(value) = pdu_json.get_mut("auth_events") {
+			mutate_outgoing_reference_format(value);
+		}
+		if let Some(value) = pdu_json.get_mut("prev_events") {
+			mutate_outgoing_reference_format(value);
+		}
+	}
+
 	pdu_json
 }
+
+fn mutate_outgoing_reference_format(value: &mut CanonicalJsonValue) {
+	value
+		.as_array_mut()
+		.into_iter()
+		.flatten()
+		.for_each(|value| {
+			if let Some(event_id) = value.as_str().map(ToOwned::to_owned) {
+				*value = CanonicalJsonValue::Array(vec![
+					CanonicalJsonValue::String(event_id),
+					CanonicalJsonValue::Object([(String::new(), "".into())].into()),
+				]);
+			}
+		});
+}
+
+pub fn from_incoming_federation(
+	event_id: &EventId,
+	pdu_json: &mut CanonicalJsonObject,
+	room_rules: &RoomVersionRules,
+) -> Result<PduEvent> {
+	if matches!(room_rules.events_reference_format, EventsReferenceFormatVersion::V1) {
+		if let Some(value) = pdu_json.get_mut("auth_events") {
+			mutate_incoming_reference_format(value);
+		}
+		if let Some(value) = pdu_json.get_mut("prev_events") {
+			mutate_incoming_reference_format(value);
+		}
+	}
+
+	pdu_json.insert("event_id".to_owned(), CanonicalJsonValue::String(event_id.into()));
+
+	serde_json::from_value::<PduEvent>(serde_json::to_value(&pdu_json)?)
+		.map_err(|e| err!(Request(BadJson(debug_warn!("Event is not a valid PDU: {e}")))))
+}
+
+fn mutate_incoming_reference_format(value: &mut CanonicalJsonValue) {
+	value
+		.as_array_mut()
+		.into_iter()
+		.flat_map(|vec| vec.iter_mut())
+		.for_each(|value| {
+			let event_id = value
+				.as_array()
+				.into_iter()
+				.find_map(|vec| vec.first())
+				.and_then(|val| extract_variant!(val, CanonicalJsonValue::String))
+				.cloned()
+				.unwrap_or_default();
+
+			*value = CanonicalJsonValue::String(event_id);
+		});
+}