PoC

src/service/globals/mod.rs

@@ -1,9 +1,11 @@
 mod data;
 pub use data::{Data, SigningKeys};
+
 use ruma::{
     serde::Base64, MilliSecondsSinceUnixEpoch, OwnedDeviceId, OwnedEventId, OwnedRoomAliasId,
     OwnedRoomId, OwnedServerName, OwnedUserId, RoomAliasId,
 };
+use tokio::sync::OnceCell;
 
 use crate::api::server_server::DestinationResponse;
 
@@ -17,7 +19,7 @@ use ruma::{
     DeviceId, RoomVersionId, ServerName, UserId,
 };
 use std::{
-    collections::{BTreeMap, HashMap},
+    collections::{BTreeMap, BTreeSet, HashMap},
     error::Error as StdError,
     fs,
     future::{self, Future},
@@ -33,7 +35,7 @@ use std::{
 };
 use tokio::sync::{broadcast, watch::Receiver, Mutex, RwLock, Semaphore};
 use tower_service::Service as TowerService;
-use tracing::{error, info};
+use tracing::{error, info, warn};
 
 use base64::{engine::general_purpose, Engine as _};
 
@@ -68,6 +70,7 @@ pub struct Service {
     pub roomid_mutex_state: RwLock<HashMap<OwnedRoomId, Arc<Mutex<()>>>>,
     pub roomid_mutex_federation: RwLock<HashMap<OwnedRoomId, Arc<Mutex<()>>>>, // this lock will be held longer
     pub roomid_federationhandletime: RwLock<HashMap<OwnedRoomId, (OwnedEventId, Instant)>>,
+    join_by_default: OnceCell<BTreeSet<OwnedRoomId>>,
     server_user: OwnedUserId,
     admin_alias: OwnedRoomAliasId,
     pub stateres_mutex: Arc<Mutex<()>>,
@@ -221,6 +224,7 @@ impl Service {
             roomid_mutex_insert: RwLock::new(HashMap::new()),
             roomid_mutex_federation: RwLock::new(HashMap::new()),
             roomid_federationhandletime: RwLock::new(HashMap::new()),
+            join_by_default: OnceCell::new(),
             stateres_mutex: Arc::new(Mutex::new(())),
             sync_receivers: RwLock::new(HashMap::new()),
             rotate: RotationHandler::new(),
@@ -505,6 +509,49 @@ impl Service {
         self.config.well_known_client()
     }
 
+    pub fn join_by_default(&self) -> Result<&BTreeSet<OwnedRoomId>> {
+        if let Some(set) = self.join_by_default.get() {
+            return Ok(set);
+        }
+
+        let server_name = self.config.server_name.as_str();
+        let mut join_by_default = BTreeSet::new();
+
+        for s in self.config.join_by_default.iter().cloned() {
+            let next = s
+                .chars()
+                .next()
+                .ok_or_else(|| Error::bad_config("Invalid room ID for join-by-default."))?;
+
+            let room_id = if next == '!' {
+                let id = s.split(':').next().unwrap_or(&s);
+
+                OwnedRoomId::from_str(&format!("{id}:{server_name}",))
+                    .map_err(|_| Error::bad_config("Invalid room ID for join-by-default rooms."))?
+            } else {
+                let id = s.split(':').next().unwrap_or(&s).trim_start_matches('#');
+
+                let alias = OwnedRoomAliasId::from_str(&format!("#{id}:{server_name}",))
+                    .map_err(|_| Error::bad_config("Invalid room alias for join-by-default."))?;
+
+                let Some(room_id) = services().rooms.alias.resolve_local_alias(&alias)? else {
+                    warn!("Could not resolve Room ID for join-by-default rooms locally.");
+                    continue;
+                };
+
+                room_id
+            };
+
+            join_by_default.insert(room_id);
+        }
+
+        self.join_by_default
+            .set(join_by_default)
+            .expect("join_by_default should be set once");
+
+        self.join_by_default()
+    }
+
     pub fn shutdown(&self) {
         self.shutdown.store(true, atomic::Ordering::Relaxed);
         // On shutdown