matrix_sdk_base/room/
latest_event.rs

1// Copyright 2025 The Matrix.org Foundation C.I.C.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#[cfg(feature = "e2e-encryption")]
16use std::{collections::BTreeMap, num::NonZeroUsize};
17
18#[cfg(feature = "e2e-encryption")]
19use ruma::{events::AnySyncTimelineEvent, serde::Raw, OwnedRoomId};
20
21use super::Room;
22#[cfg(feature = "e2e-encryption")]
23use super::RoomInfoNotableUpdateReasons;
24use crate::latest_event::LatestEvent;
25
26impl Room {
27    /// The size of the latest_encrypted_events RingBuffer
28    #[cfg(feature = "e2e-encryption")]
29    pub(super) const MAX_ENCRYPTED_EVENTS: NonZeroUsize = NonZeroUsize::new(10).unwrap();
30
31    /// Return the last event in this room, if one has been cached during
32    /// sliding sync.
33    pub fn latest_event(&self) -> Option<LatestEvent> {
34        self.inner.read().latest_event.as_deref().cloned()
35    }
36
37    /// Return the most recent few encrypted events. When the keys come through
38    /// to decrypt these, the most recent relevant one will replace
39    /// latest_event. (We can't tell which one is relevant until
40    /// they are decrypted.)
41    #[cfg(feature = "e2e-encryption")]
42    pub(crate) fn latest_encrypted_events(&self) -> Vec<Raw<AnySyncTimelineEvent>> {
43        self.latest_encrypted_events.read().unwrap().iter().cloned().collect()
44    }
45
46    /// Replace our latest_event with the supplied event, and delete it and all
47    /// older encrypted events from latest_encrypted_events, given that the
48    /// new event was at the supplied index in the latest_encrypted_events
49    /// list.
50    ///
51    /// Panics if index is not a valid index in the latest_encrypted_events
52    /// list.
53    ///
54    /// It is the responsibility of the caller to apply the changes into the
55    /// state store after calling this function.
56    #[cfg(feature = "e2e-encryption")]
57    pub(crate) fn on_latest_event_decrypted(
58        &self,
59        latest_event: Box<LatestEvent>,
60        index: usize,
61        changes: &mut crate::StateChanges,
62        room_info_notable_updates: &mut BTreeMap<OwnedRoomId, RoomInfoNotableUpdateReasons>,
63    ) {
64        self.latest_encrypted_events.write().unwrap().drain(0..=index);
65
66        let room_info = changes
67            .room_infos
68            .entry(self.room_id().to_owned())
69            .or_insert_with(|| self.clone_info());
70
71        room_info.latest_event = Some(latest_event);
72
73        room_info_notable_updates
74            .entry(self.room_id().to_owned())
75            .or_default()
76            .insert(RoomInfoNotableUpdateReasons::LATEST_EVENT);
77    }
78}
79
80#[cfg(all(test, feature = "e2e-encryption"))]
81mod tests_with_e2e_encryption {
82    use std::sync::Arc;
83
84    use assert_matches::assert_matches;
85    use matrix_sdk_common::deserialized_responses::TimelineEvent;
86    use matrix_sdk_test::async_test;
87    use ruma::{room_id, serde::Raw, user_id};
88    use serde_json::json;
89
90    use crate::{
91        latest_event::LatestEvent,
92        response_processors as processors,
93        store::{MemoryStore, RoomLoadSettings, StoreConfig},
94        BaseClient, Room, RoomInfoNotableUpdate, RoomInfoNotableUpdateReasons, RoomState,
95        SessionMeta, StateChanges,
96    };
97
98    fn make_room_test_helper(room_type: RoomState) -> (Arc<MemoryStore>, Room) {
99        let store = Arc::new(MemoryStore::new());
100        let user_id = user_id!("@me:example.org");
101        let room_id = room_id!("!test:localhost");
102        let (sender, _receiver) = tokio::sync::broadcast::channel(1);
103
104        (store.clone(), Room::new(user_id, store, room_id, room_type, sender))
105    }
106
107    #[async_test]
108    async fn test_setting_the_latest_event_doesnt_cause_a_room_info_notable_update() {
109        // Given a room,
110        let client =
111            BaseClient::new(StoreConfig::new("cross-process-store-locks-holder-name".to_owned()));
112
113        client
114            .activate(
115                SessionMeta {
116                    user_id: user_id!("@alice:example.org").into(),
117                    device_id: ruma::device_id!("AYEAYEAYE").into(),
118                },
119                RoomLoadSettings::default(),
120                None,
121            )
122            .await
123            .unwrap();
124
125        let room_id = room_id!("!test:localhost");
126        let room = client.get_or_create_room(room_id, RoomState::Joined);
127
128        // That has an encrypted event,
129        add_encrypted_event(&room, "$A");
130        // Sanity: it has no latest_event
131        assert!(room.latest_event().is_none());
132
133        // When I set up an observer on the latest_event,
134        let mut room_info_notable_update = client.room_info_notable_update_receiver();
135
136        // And I provide a decrypted event to replace the encrypted one,
137        let event = make_latest_event("$A");
138
139        let mut context = processors::Context::default();
140        room.on_latest_event_decrypted(
141            event.clone(),
142            0,
143            &mut context.state_changes,
144            &mut context.room_info_notable_updates,
145        );
146
147        assert!(context.room_info_notable_updates.contains_key(room_id));
148
149        // The subscriber isn't notified at this point.
150        assert!(room_info_notable_update.is_empty());
151
152        // Then updating the room info will store the event,
153        processors::changes::save_and_apply(
154            context,
155            &client.state_store,
156            &client.ignore_user_list_changes,
157            None,
158        )
159        .await
160        .unwrap();
161
162        assert_eq!(room.latest_event().unwrap().event_id(), event.event_id());
163
164        // And wake up the subscriber.
165        assert_matches!(
166            room_info_notable_update.recv().await,
167            Ok(RoomInfoNotableUpdate { room_id: received_room_id, reasons }) => {
168                assert_eq!(received_room_id, room_id);
169                assert!(reasons.contains(RoomInfoNotableUpdateReasons::LATEST_EVENT));
170            }
171        );
172    }
173
174    #[async_test]
175    async fn test_when_we_provide_a_newly_decrypted_event_it_replaces_latest_event() {
176        use std::collections::BTreeMap;
177
178        // Given a room with an encrypted event
179        let (_store, room) = make_room_test_helper(RoomState::Joined);
180        add_encrypted_event(&room, "$A");
181        // Sanity: it has no latest_event
182        assert!(room.latest_event().is_none());
183
184        // When I provide a decrypted event to replace the encrypted one
185        let event = make_latest_event("$A");
186        let mut changes = StateChanges::default();
187        let mut room_info_notable_updates = BTreeMap::new();
188        room.on_latest_event_decrypted(
189            event.clone(),
190            0,
191            &mut changes,
192            &mut room_info_notable_updates,
193        );
194        room.set_room_info(
195            changes.room_infos.get(room.room_id()).cloned().unwrap(),
196            room_info_notable_updates.get(room.room_id()).copied().unwrap(),
197        );
198
199        // Then is it stored
200        assert_eq!(room.latest_event().unwrap().event_id(), event.event_id());
201    }
202
203    #[cfg(feature = "e2e-encryption")]
204    #[async_test]
205    async fn test_when_a_newly_decrypted_event_appears_we_delete_all_older_encrypted_events() {
206        // Given a room with some encrypted events and a latest event
207
208        use std::collections::BTreeMap;
209        let (_store, room) = make_room_test_helper(RoomState::Joined);
210        room.inner.update(|info| info.latest_event = Some(make_latest_event("$A")));
211        add_encrypted_event(&room, "$0");
212        add_encrypted_event(&room, "$1");
213        add_encrypted_event(&room, "$2");
214        add_encrypted_event(&room, "$3");
215
216        // When I provide a latest event
217        let new_event = make_latest_event("$1");
218        let new_event_index = 1;
219        let mut changes = StateChanges::default();
220        let mut room_info_notable_updates = BTreeMap::new();
221        room.on_latest_event_decrypted(
222            new_event.clone(),
223            new_event_index,
224            &mut changes,
225            &mut room_info_notable_updates,
226        );
227        room.set_room_info(
228            changes.room_infos.get(room.room_id()).cloned().unwrap(),
229            room_info_notable_updates.get(room.room_id()).copied().unwrap(),
230        );
231
232        // Then the encrypted events list is shortened to only newer events
233        let enc_evs = room.latest_encrypted_events();
234        assert_eq!(enc_evs.len(), 2);
235        assert_eq!(enc_evs[0].get_field::<&str>("event_id").unwrap().unwrap(), "$2");
236        assert_eq!(enc_evs[1].get_field::<&str>("event_id").unwrap().unwrap(), "$3");
237
238        // And the event is stored
239        assert_eq!(room.latest_event().unwrap().event_id(), new_event.event_id());
240    }
241
242    #[async_test]
243    async fn test_replacing_the_newest_event_leaves_none_left() {
244        use std::collections::BTreeMap;
245
246        // Given a room with some encrypted events
247        let (_store, room) = make_room_test_helper(RoomState::Joined);
248        add_encrypted_event(&room, "$0");
249        add_encrypted_event(&room, "$1");
250        add_encrypted_event(&room, "$2");
251        add_encrypted_event(&room, "$3");
252
253        // When I provide a latest event and say it was the very latest
254        let new_event = make_latest_event("$3");
255        let new_event_index = 3;
256        let mut changes = StateChanges::default();
257        let mut room_info_notable_updates = BTreeMap::new();
258        room.on_latest_event_decrypted(
259            new_event,
260            new_event_index,
261            &mut changes,
262            &mut room_info_notable_updates,
263        );
264        room.set_room_info(
265            changes.room_infos.get(room.room_id()).cloned().unwrap(),
266            room_info_notable_updates.get(room.room_id()).copied().unwrap(),
267        );
268
269        // Then the encrypted events list ie empty
270        let enc_evs = room.latest_encrypted_events();
271        assert_eq!(enc_evs.len(), 0);
272    }
273
274    fn add_encrypted_event(room: &Room, event_id: &str) {
275        room.latest_encrypted_events
276            .write()
277            .unwrap()
278            .push(Raw::from_json_string(json!({ "event_id": event_id }).to_string()).unwrap());
279    }
280
281    fn make_latest_event(event_id: &str) -> Box<LatestEvent> {
282        Box::new(LatestEvent::new(TimelineEvent::new(
283            Raw::from_json_string(json!({ "event_id": event_id }).to_string()).unwrap(),
284        )))
285    }
286}
matrix_sdk_base/room/latest_event.rs

matrix_sdk_base/room/
latest_event.rs
