matrix_sdk_base/event_cache/store/
traits.rs

1// Copyright 2024 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
15use std::{fmt, sync::Arc};
16
17use async_trait::async_trait;
18use matrix_sdk_common::{
19    AsyncTraitDeps,
20    cross_process_lock::CrossProcessLockGeneration,
21    linked_chunk::{
22        ChunkIdentifier, ChunkIdentifierGenerator, ChunkMetadata, LinkedChunkId, Position,
23        RawChunk, Update,
24    },
25};
26use ruma::{EventId, OwnedEventId, RoomId, events::relation::RelationType};
27
28use super::EventCacheStoreError;
29use crate::event_cache::{Event, Gap};
30
31/// A default capacity for linked chunks, when manipulating in conjunction with
32/// an `EventCacheStore` implementation.
33// TODO: move back?
34pub const DEFAULT_CHUNK_CAPACITY: usize = 128;
35
36/// An abstract trait that can be used to implement different store backends
37/// for the event cache of the SDK.
38#[cfg_attr(target_family = "wasm", async_trait(?Send))]
39#[cfg_attr(not(target_family = "wasm"), async_trait)]
40pub trait EventCacheStore: AsyncTraitDeps {
41    /// The error type used by this event cache store.
42    type Error: fmt::Debug + Into<EventCacheStoreError>;
43
44    /// Try to take a lock using the given store.
45    async fn try_take_leased_lock(
46        &self,
47        lease_duration_ms: u32,
48        key: &str,
49        holder: &str,
50    ) -> Result<Option<CrossProcessLockGeneration>, Self::Error>;
51
52    /// An [`Update`] reflects an operation that has happened inside a linked
53    /// chunk. The linked chunk is used by the event cache to store the events
54    /// in-memory. This method aims at forwarding this update inside this store.
55    async fn handle_linked_chunk_updates(
56        &self,
57        linked_chunk_id: LinkedChunkId<'_>,
58        updates: Vec<Update<Event, Gap>>,
59    ) -> Result<(), Self::Error>;
60
61    /// Remove all data tied to a given room from the cache.
62    async fn remove_room(&self, room_id: &RoomId) -> Result<(), Self::Error> {
63        // Right now, this means removing all the linked chunk. If implementations
64        // override this behavior, they should *also* include this code.
65        self.handle_linked_chunk_updates(LinkedChunkId::Room(room_id), vec![Update::Clear]).await
66    }
67
68    /// Return all the raw components of a linked chunk, so the caller may
69    /// reconstruct the linked chunk later.
70    #[doc(hidden)]
71    async fn load_all_chunks(
72        &self,
73        linked_chunk_id: LinkedChunkId<'_>,
74    ) -> Result<Vec<RawChunk<Event, Gap>>, Self::Error>;
75
76    /// Load all of the chunks' metadata for the given [`LinkedChunkId`].
77    ///
78    /// Chunks are unordered, and there's no guarantee that the chunks would
79    /// form a valid linked chunk after reconstruction.
80    async fn load_all_chunks_metadata(
81        &self,
82        linked_chunk_id: LinkedChunkId<'_>,
83    ) -> Result<Vec<ChunkMetadata>, Self::Error>;
84
85    /// Load the last chunk of the `LinkedChunk` holding all events of the room
86    /// identified by `room_id`.
87    ///
88    /// This is used to iteratively load events for the `EventCache`.
89    async fn load_last_chunk(
90        &self,
91        linked_chunk_id: LinkedChunkId<'_>,
92    ) -> Result<(Option<RawChunk<Event, Gap>>, ChunkIdentifierGenerator), Self::Error>;
93
94    /// Load the chunk before the chunk identified by `before_chunk_identifier`
95    /// of the `LinkedChunk` holding all events of the room identified by
96    /// `room_id`
97    ///
98    /// This is used to iteratively load events for the `EventCache`.
99    async fn load_previous_chunk(
100        &self,
101        linked_chunk_id: LinkedChunkId<'_>,
102        before_chunk_identifier: ChunkIdentifier,
103    ) -> Result<Option<RawChunk<Event, Gap>>, Self::Error>;
104
105    /// Clear persisted events for all the rooms.
106    ///
107    /// This will empty and remove all the linked chunks stored previously,
108    /// using the above [`Self::handle_linked_chunk_updates`] methods. It
109    /// *also* deletes all the events' content.
110    ///
111    /// ⚠ This is meant only for super specific use cases, where there shouldn't
112    /// be any live in-memory linked chunks. In general, prefer using
113    /// `EventCache::clear_all_rooms()` from the common SDK crate.
114    async fn clear_all_events(&self) -> Result<(), Self::Error>;
115
116    /// Given a set of event IDs, return the duplicated events along with their
117    /// position if there are any.
118    async fn filter_duplicated_events(
119        &self,
120        linked_chunk_id: LinkedChunkId<'_>,
121        events: Vec<OwnedEventId>,
122    ) -> Result<Vec<(OwnedEventId, Position)>, Self::Error>;
123
124    /// Find an event by its ID in a room.
125    ///
126    /// This method must return events saved either in any linked chunks, *or*
127    /// events saved "out-of-band" with the [`Self::save_event`] method.
128    async fn find_event(
129        &self,
130        room_id: &RoomId,
131        event_id: &EventId,
132    ) -> Result<Option<Event>, Self::Error>;
133
134    /// Find all the events (alongside their position in the room's linked
135    /// chunk, if available) that relate to a given event.
136    ///
137    /// The only events which don't have a position are those which have been
138    /// saved out-of-band using [`Self::save_event`].
139    ///
140    /// Note: it doesn't process relations recursively: for instance, if
141    /// requesting only thread events, it will NOT return the aggregated
142    /// events affecting the returned events. It is the responsibility of
143    /// the caller to do so, if needed.
144    ///
145    /// An additional filter can be provided to only retrieve related events for
146    /// a certain relationship.
147    ///
148    /// This method must return events saved either in any linked chunks, *or*
149    /// events saved "out-of-band" with the [`Self::save_event`] method.
150    async fn find_event_relations(
151        &self,
152        room_id: &RoomId,
153        event_id: &EventId,
154        filter: Option<&[RelationType]>,
155    ) -> Result<Vec<(Event, Option<Position>)>, Self::Error>;
156
157    /// Get all events in this room.
158    ///
159    /// This method must return events saved either in any linked chunks, *or*
160    /// events saved "out-of-band" with the [`Self::save_event`] method.
161    async fn get_room_events(
162        &self,
163        room_id: &RoomId,
164        event_type: Option<&str>,
165        session_id: Option<&str>,
166    ) -> Result<Vec<Event>, Self::Error>;
167
168    /// Save an event, that might or might not be part of an existing linked
169    /// chunk.
170    ///
171    /// If the event has no event id, it will not be saved, and the function
172    /// must return an Ok result early.
173    ///
174    /// If the event was already stored with the same id, it must be replaced,
175    /// without causing an error.
176    async fn save_event(&self, room_id: &RoomId, event: Event) -> Result<(), Self::Error>;
177
178    /// Close the store, releasing all held resources (database connections,
179    /// file descriptors, file locks).
180    ///
181    /// In-flight operations complete before this method returns. After it
182    /// returns, operations will fail until [`Self::reopen()`] is called.
183    async fn close(&self) -> Result<(), Self::Error>;
184
185    /// Reopen the store after a [`Self::close()`], re-acquiring database
186    /// connections.
187    async fn reopen(&self) -> Result<(), Self::Error>;
188
189    /// Perform database optimizations if any are available, i.e. vacuuming in
190    /// SQLite.
191    ///
192    /// **Warning:** this was added to check if SQLite fragmentation was the
193    /// source of performance issues, **DO NOT use in production**.
194    #[doc(hidden)]
195    async fn optimize(&self) -> Result<(), Self::Error>;
196
197    /// Returns the size of the store in bytes, if known.
198    async fn get_size(&self) -> Result<Option<usize>, Self::Error>;
199}
200
201#[repr(transparent)]
202struct EraseEventCacheStoreError<T>(T);
203
204#[cfg(not(tarpaulin_include))]
205impl<T: fmt::Debug> fmt::Debug for EraseEventCacheStoreError<T> {
206    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
207        self.0.fmt(f)
208    }
209}
210
211#[cfg_attr(target_family = "wasm", async_trait(?Send))]
212#[cfg_attr(not(target_family = "wasm"), async_trait)]
213impl<T: EventCacheStore> EventCacheStore for EraseEventCacheStoreError<T> {
214    type Error = EventCacheStoreError;
215
216    async fn try_take_leased_lock(
217        &self,
218        lease_duration_ms: u32,
219        key: &str,
220        holder: &str,
221    ) -> Result<Option<CrossProcessLockGeneration>, Self::Error> {
222        self.0.try_take_leased_lock(lease_duration_ms, key, holder).await.map_err(Into::into)
223    }
224
225    async fn handle_linked_chunk_updates(
226        &self,
227        linked_chunk_id: LinkedChunkId<'_>,
228        updates: Vec<Update<Event, Gap>>,
229    ) -> Result<(), Self::Error> {
230        self.0.handle_linked_chunk_updates(linked_chunk_id, updates).await.map_err(Into::into)
231    }
232
233    async fn load_all_chunks(
234        &self,
235        linked_chunk_id: LinkedChunkId<'_>,
236    ) -> Result<Vec<RawChunk<Event, Gap>>, Self::Error> {
237        self.0.load_all_chunks(linked_chunk_id).await.map_err(Into::into)
238    }
239
240    async fn load_all_chunks_metadata(
241        &self,
242        linked_chunk_id: LinkedChunkId<'_>,
243    ) -> Result<Vec<ChunkMetadata>, Self::Error> {
244        self.0.load_all_chunks_metadata(linked_chunk_id).await.map_err(Into::into)
245    }
246
247    async fn load_last_chunk(
248        &self,
249        linked_chunk_id: LinkedChunkId<'_>,
250    ) -> Result<(Option<RawChunk<Event, Gap>>, ChunkIdentifierGenerator), Self::Error> {
251        self.0.load_last_chunk(linked_chunk_id).await.map_err(Into::into)
252    }
253
254    async fn load_previous_chunk(
255        &self,
256        linked_chunk_id: LinkedChunkId<'_>,
257        before_chunk_identifier: ChunkIdentifier,
258    ) -> Result<Option<RawChunk<Event, Gap>>, Self::Error> {
259        self.0
260            .load_previous_chunk(linked_chunk_id, before_chunk_identifier)
261            .await
262            .map_err(Into::into)
263    }
264
265    async fn clear_all_events(&self) -> Result<(), Self::Error> {
266        self.0.clear_all_events().await.map_err(Into::into)
267    }
268
269    async fn filter_duplicated_events(
270        &self,
271        linked_chunk_id: LinkedChunkId<'_>,
272        events: Vec<OwnedEventId>,
273    ) -> Result<Vec<(OwnedEventId, Position)>, Self::Error> {
274        self.0.filter_duplicated_events(linked_chunk_id, events).await.map_err(Into::into)
275    }
276
277    async fn find_event(
278        &self,
279        room_id: &RoomId,
280        event_id: &EventId,
281    ) -> Result<Option<Event>, Self::Error> {
282        self.0.find_event(room_id, event_id).await.map_err(Into::into)
283    }
284
285    async fn find_event_relations(
286        &self,
287        room_id: &RoomId,
288        event_id: &EventId,
289        filter: Option<&[RelationType]>,
290    ) -> Result<Vec<(Event, Option<Position>)>, Self::Error> {
291        self.0.find_event_relations(room_id, event_id, filter).await.map_err(Into::into)
292    }
293
294    async fn get_room_events(
295        &self,
296        room_id: &RoomId,
297        event_type: Option<&str>,
298        session_id: Option<&str>,
299    ) -> Result<Vec<Event>, Self::Error> {
300        self.0.get_room_events(room_id, event_type, session_id).await.map_err(Into::into)
301    }
302
303    async fn save_event(&self, room_id: &RoomId, event: Event) -> Result<(), Self::Error> {
304        self.0.save_event(room_id, event).await.map_err(Into::into)
305    }
306
307    async fn close(&self) -> Result<(), Self::Error> {
308        self.0.close().await.map_err(Into::into)
309    }
310
311    async fn reopen(&self) -> Result<(), Self::Error> {
312        self.0.reopen().await.map_err(Into::into)
313    }
314
315    async fn optimize(&self) -> Result<(), Self::Error> {
316        self.0.optimize().await.map_err(Into::into)?;
317        Ok(())
318    }
319
320    async fn get_size(&self) -> Result<Option<usize>, Self::Error> {
321        Ok(self.0.get_size().await.map_err(Into::into)?)
322    }
323}
324
325/// A type-erased [`EventCacheStore`].
326pub type DynEventCacheStore = dyn EventCacheStore<Error = EventCacheStoreError>;
327
328/// A type that can be type-erased into `Arc<dyn EventCacheStore>`.
329///
330/// This trait is not meant to be implemented directly outside
331/// `matrix-sdk-base`, but it is automatically implemented for everything that
332/// implements `EventCacheStore`.
333pub trait IntoEventCacheStore {
334    #[doc(hidden)]
335    fn into_event_cache_store(self) -> Arc<DynEventCacheStore>;
336}
337
338impl IntoEventCacheStore for Arc<DynEventCacheStore> {
339    fn into_event_cache_store(self) -> Arc<DynEventCacheStore> {
340        self
341    }
342}
343
344impl<T> IntoEventCacheStore for T
345where
346    T: EventCacheStore + Sized + 'static,
347{
348    fn into_event_cache_store(self) -> Arc<DynEventCacheStore> {
349        Arc::new(EraseEventCacheStoreError(self))
350    }
351}
352
353// Turns a given `Arc<T>` into `Arc<DynEventCacheStore>` by attaching the
354// `EventCacheStore` impl vtable of `EraseEventCacheStoreError<T>`.
355impl<T> IntoEventCacheStore for Arc<T>
356where
357    T: EventCacheStore + 'static,
358{
359    fn into_event_cache_store(self) -> Arc<DynEventCacheStore> {
360        let ptr: *const T = Arc::into_raw(self);
361        let ptr_erased = ptr as *const EraseEventCacheStoreError<T>;
362        // SAFETY: EraseEventCacheStoreError is repr(transparent) so T and
363        //         EraseEventCacheStoreError<T> have the same layout and ABI
364        unsafe { Arc::from_raw(ptr_erased) }
365    }
366}
matrix_sdk_base/event_cache/store/traits.rs

matrix_sdk_base/event_cache/store/
traits.rs
