Cleanup/improve other async queries in some client handlers.

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

src/api/client/membership/forget.rs

@@ -0,0 +1,52 @@
+use axum::extract::State;
+use conduwuit::{Err, Result, is_matching, result::NotFound, utils::FutureBoolExt};
+use futures::pin_mut;
+use ruma::{api::client::membership::forget_room, events::room::member::MembershipState};
+
+use crate::Ruma;
+
+/// # `POST /_matrix/client/v3/rooms/{roomId}/forget`
+///
+/// Forgets about a room.
+///
+/// - If the sender user currently left the room: Stops sender user from
+///   receiving information about the room
+///
+/// Note: Other devices of the user have no way of knowing the room was
+/// forgotten, so this has to be called from every device
+pub(crate) async fn forget_room_route(
+	State(services): State<crate::State>,
+	body: Ruma<forget_room::v3::Request>,
+) -> Result<forget_room::v3::Response> {
+	let user_id = body.sender_user();
+	let room_id = &body.room_id;
+
+	let joined = services.rooms.state_cache.is_joined(user_id, room_id);
+	let knocked = services.rooms.state_cache.is_knocked(user_id, room_id);
+	let invited = services.rooms.state_cache.is_invited(user_id, room_id);
+
+	pin_mut!(joined, knocked, invited);
+	if joined.or(knocked).or(invited).await {
+		return Err!(Request(Unknown("You must leave the room before forgetting it")));
+	}
+
+	let membership = services
+		.rooms
+		.state_accessor
+		.get_member(room_id, user_id)
+		.await;
+
+	if membership.is_not_found() {
+		return Err!(Request(Unknown("No membership event was found, room was never joined")));
+	}
+
+	let non_membership = membership
+		.map(|member| member.membership)
+		.is_ok_and(is_matching!(MembershipState::Leave | MembershipState::Ban));
+
+	if non_membership || services.rooms.state_cache.is_left(user_id, room_id).await {
+		services.rooms.state_cache.forget(room_id, user_id);
+	}
+
+	Ok(forget_room::v3::Response::new())
+}