feat(base): Add EventCacheStore::handle_linked_chunk_updates.

This patch adds the `handle_linked_chunk_updates` method on the
`EventCacheStore` trait. Part of
https://github.com/matrix-org/matrix-rust-sdk/issues/3280.

crates/matrix-sdk-base/src/event_cache/store/memory_store.rs

@@ -16,12 +16,16 @@ use std::{collections::HashMap, num::NonZeroUsize, sync::RwLock as StdRwLock, ti
 
 use async_trait::async_trait;
 use matrix_sdk_common::{
-    ring_buffer::RingBuffer, store_locks::memory_store_helper::try_take_leased_lock,
+    linked_chunk::Update, ring_buffer::RingBuffer,
+    store_locks::memory_store_helper::try_take_leased_lock,
 };
 use ruma::{MxcUri, OwnedMxcUri};
 
 use super::{EventCacheStore, EventCacheStoreError, Result};
-use crate::media::{MediaRequestParameters, UniqueKey as _};
+use crate::{
+    event_cache::{Event, Gap},
+    media::{MediaRequestParameters, UniqueKey as _},
+};
 
 /// In-memory, non-persistent implementation of the `EventCacheStore`.
 ///
@@ -66,6 +70,13 @@ impl EventCacheStore for MemoryStore {
         Ok(try_take_leased_lock(&self.leases, lease_duration_ms, key, holder))
     }
 
+    async fn handle_linked_chunk_updates(
+        &self,
+        _updates: &[Update<Event, Gap>],
+    ) -> Result<(), Self::Error> {
+        todo!()
+    }
+
     async fn add_media_content(
         &self,
         request: &MediaRequestParameters,

crates/matrix-sdk-base/src/event_cache/store/traits.rs

@@ -15,11 +15,14 @@
 use std::{fmt, sync::Arc};
 
 use async_trait::async_trait;
-use matrix_sdk_common::AsyncTraitDeps;
+use matrix_sdk_common::{linked_chunk::Update, AsyncTraitDeps};
 use ruma::MxcUri;
 
 use super::EventCacheStoreError;
-use crate::media::MediaRequestParameters;
+use crate::{
+    event_cache::{Event, Gap},
+    media::MediaRequestParameters,
+};
 
 /// An abstract trait that can be used to implement different store backends
 /// for the event cache of the SDK.
@@ -37,6 +40,14 @@ pub trait EventCacheStore: AsyncTraitDeps {
         holder: &str,
     ) -> Result<bool, Self::Error>;
 
+    /// An [`Update`] reflects an operation that has happened inside a linked
+    /// chunk. The linked chunk is used by the event cache to store the events
+    /// in-memory. This method aims at forwarding this update inside this store.
+    async fn handle_linked_chunk_updates(
+        &self,
+        updates: &[Update<Event, Gap>],
+    ) -> Result<(), Self::Error>;
+
     /// Add a media file's content in the media store.
     ///
     /// # Arguments
@@ -131,6 +142,13 @@ impl<T: EventCacheStore> EventCacheStore for EraseEventCacheStoreError<T> {
         self.0.try_take_leased_lock(lease_duration_ms, key, holder).await.map_err(Into::into)
     }
 
+    async fn handle_linked_chunk_updates(
+        &self,
+        updates: &[Update<Event, Gap>],
+    ) -> Result<(), Self::Error> {
+        self.0.handle_linked_chunk_updates(updates).await.map_err(Into::into)
+    }
+
     async fn add_media_content(
         &self,
         request: &MediaRequestParameters,

crates/matrix-sdk-common/src/linked_chunk/mod.rs

@@ -103,8 +103,8 @@ use std::{
     sync::atomic::{AtomicU64, Ordering},
 };
 
-use as_vector::*;
-use updates::*;
+pub use as_vector::*;
+pub use updates::*;
 
 /// Errors of [`LinkedChunk`].
 #[derive(thiserror::Error, Debug)]

crates/matrix-sdk-common/src/linked_chunk/updates.rs

@@ -29,6 +29,9 @@ use super::{ChunkIdentifier, Position};
 ///
 /// These updates are useful to store a `LinkedChunk` in another form of
 /// storage, like a database or something similar.
+///
+/// [`LinkedChunk`]: super::LinkedChunk
+/// [`LinkedChunk::updates`]: super::LinkedChunk::updates
 #[derive(Debug, Clone, PartialEq)]
 pub enum Update<Item, Gap> {
     /// A new chunk of kind Items has been created.
@@ -101,6 +104,8 @@ pub enum Update<Item, Gap> {
 /// A collection of [`Update`]s that can be observed.
 ///
 /// Get a value for this type with [`LinkedChunk::updates`].
+///
+/// [`LinkedChunk::updates`]: super::LinkedChunk::updates
 #[derive(Debug)]
 pub struct ObservableUpdates<Item, Gap> {
     pub(super) inner: Arc<RwLock<UpdatesInner<Item, Gap>>>,

crates/matrix-sdk-sqlite/src/event_cache_store.rs

@@ -3,7 +3,8 @@ use std::{borrow::Cow, fmt, path::Path, sync::Arc};
 use async_trait::async_trait;
 use deadpool_sqlite::{Object as SqliteAsyncConn, Pool as SqlitePool, Runtime};
 use matrix_sdk_base::{
-    event_cache::store::EventCacheStore,
+    event_cache::{store::EventCacheStore, Event, Gap},
+    linked_chunk::Update,
     media::{MediaRequestParameters, UniqueKey},
 };
 use matrix_sdk_store_encryption::StoreCipher;
@@ -182,6 +183,13 @@ impl EventCacheStore for SqliteEventCacheStore {
         Ok(num_touched == 1)
     }
 
+    async fn handle_linked_chunk_updates(
+        &self,
+        _updates: &[Update<Event, Gap>],
+    ) -> Result<(), Self::Error> {
+        todo!()
+    }
+
     async fn add_media_content(
         &self,
         request: &MediaRequestParameters,