WIP: Draft implementation of RLS

src/@types/global.d.ts

@@ -47,6 +47,7 @@ import { type DeepReadonly } from "./common";
 import type MatrixChat from "../components/structures/MatrixChat";
 import { type InitialCryptoSetupStore } from "../stores/InitialCryptoSetupStore";
 import { type ModuleApiType } from "../modules/Api.ts";
+import type RoomListStoreV3 from "../stores/room-list-v3/RoomListStoreV3.ts";
 
 /* eslint-disable @typescript-eslint/naming-convention */
 
@@ -99,6 +100,7 @@ declare global {
         mxToastStore: ToastStore;
         mxDeviceListener: DeviceListener;
         mxRoomListStore: RoomListStore;
+        mxRoomListStoreV3: RoomListStoreV3;
         mxRoomListLayoutStore: RoomListLayoutStore;
         mxPlatformPeg: PlatformPeg;
         mxIntegrationManagers: typeof IntegrationManagers;

src/stores/room-list-v3/RoomListStoreV3.ts

@@ -0,0 +1,133 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { EmptyObject, Room } from "matrix-js-sdk/src/matrix";
+import type { MatrixDispatcher } from "../../dispatcher/dispatcher";
+import type { ActionPayload } from "../../dispatcher/payloads";
+import type { Filter, FilterKey } from "./filters";
+import type { Sorter } from "./sorters";
+import { AsyncStoreWithClient } from "../AsyncStoreWithClient";
+import SettingsStore from "../../settings/SettingsStore";
+import { VisibilityProvider } from "../room-list/filters/VisibilityProvider";
+import defaultDispatcher from "../../dispatcher/dispatcher";
+import { LISTS_UPDATE_EVENT } from "../room-list/RoomListStore";
+import { AllRoomsFilter } from "./filters/AllRoomsFilter";
+import { FavouriteFilter } from "./filters/FavouriteFilter";
+import { RecencySorter } from "./sorters/RecencySorter";
+
+export class RoomListStoreV3Class extends AsyncStoreWithClient<EmptyObject> {
+    /**
+     * This is the unsorted, unfiltered raw list of rooms from the js-sdk.
+     */
+    private rooms: Room[] = [];
+
+    private readonly msc3946ProcessDynamicPredecessor: boolean;
+
+    /**
+     * Mapping from FilterKey | string to a set of Rooms
+     */
+    private filteredRooms: Map<FilterKey, Set<Room>> = new Map();
+    private sortedRooms: Room[] = [];
+
+    private readonly filters: Filter[] = [new AllRoomsFilter(), new FavouriteFilter()];
+    private sorter: Sorter = new RecencySorter();
+
+    public constructor(dispatcher: MatrixDispatcher) {
+        super(dispatcher);
+        this.msc3946ProcessDynamicPredecessor = SettingsStore.getValue("feature_dynamic_room_predecessors");
+    }
+
+    public setSorter(sorter: Sorter): void {
+        this.sorter = sorter;
+    }
+
+    public getFilteredRooms(filters: FilterKey[]): Set<Room> | null {
+        const sets = filters.map((f) => this.filteredRooms.get(f)).filter((s) => !!s);
+        if (!sets.length) return null;
+        if (sets.length === 1) return sets[0];
+        // Find the intersection of these filtered sets
+        const intersection = new Set<Room>();
+        const [firstSet, ...otherSets] = sets;
+        for (const room of firstSet) {
+            if (!otherSets.some((set) => !set.has(room))) intersection.add(room);
+        }
+        return intersection;
+    }
+
+    public getSortedFilteredRooms(filters: FilterKey[]): Array<Room> {
+        const filteredSet = this.getFilteredRooms(filters);
+        if (!filteredSet) return this.sortedRooms;
+        return this.sortedRooms?.filter((room) => filteredSet.has(room));
+    }
+
+    protected async onReady(): Promise<any> {
+        const rooms = this.fetchRoomsFromSdk();
+        if (!rooms) return;
+        this.rooms = rooms;
+    }
+
+    protected async onAction(payload: ActionPayload): Promise<void> {
+        if (
+            ![
+                "MatrixActions.Room.receipt",
+                "MatrixActions.Room.tags",
+                "MatrixActions.Room.timeline",
+                "MatrixActions.Event.decrypted",
+                "MatrixActions.accountData",
+                "MatrixActions.Room.myMembership",
+            ].includes(payload.action)
+        )
+            return;
+        setTimeout(() => {
+            this.recalculate();
+        });
+    }
+
+    private recalculate(): void {
+        const t0 = performance.now();
+        this.fetchRoomsFromSdk();
+        this.filterRooms();
+        this.sortRooms();
+        const t1 = performance.now();
+        console.log("RLS Performance, time taken = ", t1 - t0);
+        this.emit(LISTS_UPDATE_EVENT);
+    }
+
+    private filterRooms(): void {
+        for (const filter of this.filters) {
+            const rooms = filter.filter(this.rooms);
+            this.filteredRooms.set(filter.key, new Set(rooms));
+        }
+    }
+
+    private sortRooms(): void {
+        this.sortedRooms = this.sorter.sort(this.rooms);
+    }
+
+    private fetchRoomsFromSdk(): Room[] | null {
+        if (!this.matrixClient) return null;
+        let rooms = this.matrixClient.getVisibleRooms(this.msc3946ProcessDynamicPredecessor);
+        rooms = rooms.filter((r) => VisibilityProvider.instance.isRoomVisible(r));
+        return rooms;
+    }
+}
+
+export default class RoomListStoreV3 {
+    private static internalInstance: RoomListStoreV3Class;
+
+    public static get instance(): RoomListStoreV3Class {
+        if (!RoomListStoreV3.internalInstance) {
+            const instance = new RoomListStoreV3Class(defaultDispatcher);
+            instance.start();
+            RoomListStoreV3.internalInstance = instance;
+        }
+
+        return this.internalInstance;
+    }
+}
+
+window.mxRoomListStoreV3 = RoomListStoreV3.instance;

src/stores/room-list-v3/filters/AllRoomsFilter.ts

@@ -0,0 +1,20 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { Room } from "matrix-js-sdk/src/matrix";
+import type { Filter } from ".";
+import { FilterKeysEnum } from ".";
+
+export class AllRoomsFilter implements Filter {
+    public filter(rooms: Room[]): Room[] {
+        return rooms;
+    }
+
+    public get key(): FilterKeysEnum.All {
+        return FilterKeysEnum.All;
+    }
+}

src/stores/room-list-v3/filters/FavouriteFilter.ts

@@ -0,0 +1,21 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { Room } from "matrix-js-sdk/src/matrix";
+import type { Filter } from ".";
+import { FilterKeysEnum } from ".";
+import { DefaultTagID } from "../../room-list/models";
+
+export class FavouriteFilter implements Filter {
+    public filter(rooms: Room[]): Room[] {
+        return rooms.filter((room) => !!room.tags[DefaultTagID.Favourite]);
+    }
+
+    public get key(): FilterKeysEnum.Favorite {
+        return FilterKeysEnum.Favorite;
+    }
+}

src/stores/room-list-v3/filters/index.ts

@@ -0,0 +1,20 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { Room } from "matrix-js-sdk/src/matrix";
+
+export const enum FilterKeysEnum {
+    All,
+    Favorite,
+}
+
+export type FilterKey = FilterKeysEnum | string;
+
+export interface Filter {
+    key: FilterKey;
+    filter(rooms: Room[]): Room[];
+}

src/stores/room-list-v3/sorters/AlphabeticSorter.ts

@@ -0,0 +1,18 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { Room } from "matrix-js-sdk/src/matrix";
+import type { Sorter } from ".";
+
+export class AlphabeticSorter implements Sorter {
+    public sort(rooms: Room[]): Room[] {
+        const collator = new Intl.Collator();
+        return rooms.sort((a, b) => {
+            return collator.compare(a.name, b.name);
+        });
+    }
+}

src/stores/room-list-v3/sorters/RecencySorter.ts

@@ -0,0 +1,16 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { Room } from "matrix-js-sdk/src/matrix";
+import type { Sorter } from ".";
+import { sortRooms } from "../../room-list/algorithms/tag-sorting/RecentAlgorithm";
+
+export class RecencySorter implements Sorter {
+    public sort(rooms: Room[]): Room[] {
+        return sortRooms(rooms);
+    }
+}

src/stores/room-list-v3/sorters/index.ts

@@ -0,0 +1,12 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import type { Room } from "matrix-js-sdk/src/matrix";
+
+export interface Sorter {
+    sort(rooms: Room[]): Room[];
+}