Switch sliding sync support to simplified sliding sync

src/common-crypto/CryptoBackend.ts

@@ -140,9 +140,9 @@ export interface SyncCryptoCallbacks {
     onSyncCompleted(syncState: OnSyncCompletedData): void;
 
     /**
-     * Mark all tracked user's device lists as dirty.
+     * Mark all tracked users' device lists as dirty.
      *
-     * This method will cause additional /keys/query requests on the server, so should be used only
+     * This method will cause additional `/keys/query` requests on the server, so should be used only
      * when the client has desynced tracking device list deltas from the server.
      * In MSC4186: Simplified Sliding Sync, this can happen when the server expires the connection.
      */

src/crypto-api/index.ts

@@ -418,12 +418,6 @@ export interface CryptoApi {
      */
     getEncryptionInfoForEvent(event: MatrixEvent): Promise<EventEncryptionInfo | null>;
 
-    /**
-     * All users *whose device lists we are tracking* are flagged as needing a
-     * key query. Users whose devices we are not tracking are ignored.
-     */
-    markAllTrackedUsersAsDirty(): Promise<void>;
-
     /**
      * Encrypts a given payload object via Olm to-device messages to a given
      * set of devices.

src/models/room-summary.ts

@@ -14,16 +14,51 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import type { Hero } from "./room.ts";
+/**
+ * A stripped m.room.member event which contains the key renderable fields from the event,
+ * sent only in simplified sliding sync (not sync v2).
+ */
+export type Hero = {
+    userId: string;
+    displayName?: string;
+    avatarUrl?: string;
+};
 
+/**
+ * High level summary information for a room
+ */
 export interface IRoomSummary {
+    /**
+     * The room heroes: a selected set of members that can be used when summarising or
+     * generating a name for a room. List of user IDs.
+     */
     "m.heroes": string[];
+    /**
+     * The number of joined members in the room.
+     */
     "m.joined_member_count"?: number;
+    /**
+     * The number of invited members in the room.
+     */
     "m.invited_member_count"?: number;
 }
-export interface IRoomSummaryMSC4186 {
+
+/**
+ * High level summary information for a room (MSC4186 sliding sync)
+ */
+export interface RoomSummaryMSC4186 {
+    /**
+     * The room heroes: a selected set of members that can be used when summarising or
+     * generating a name for a room.
+     */
     "m.heroes": Hero[];
+    /**
+     * The number of joined members in the room.
+     */
     "m.joined_member_count"?: number;
+    /**
+     * The number of invited members in the room.
+     */
     "m.invited_member_count"?: number;
 }
 

src/models/room.ts

@@ -35,7 +35,7 @@ import {
 } from "./event.ts";
 import { EventStatus } from "./event-status.ts";
 import { RoomMember } from "./room-member.ts";
-import { type IRoomSummary, type IRoomSummaryMSC4186, RoomSummary } from "./room-summary.ts";
+import { type IRoomSummary, type RoomSummaryMSC4186, type Hero, RoomSummary } from "./room-summary.ts";
 import { logger } from "../logger.ts";
 import { TypedReEmitter } from "../ReEmitter.ts";
 import {
@@ -178,20 +178,6 @@ export type RoomEmittedEvents =
     | BeaconEvent.LivenessChange
     | PollEvent.New;
 
-// A Hero is a stripped m.room.member event which contains the key renderable fields from the event.
-// It is used in MSC4186 (Simplified Sliding Sync) as a replacement for the old 'summary' field.
-// The old form simply contained the hero's user ID, which forced clients to then look up the
-// m.room.member event in the current state. This is entirely decoupled in SSS. To ensure this
-// works in a backwards compatible way, we will A) only set displayName/avatarUrl with server-provided
-// values, B) always prefer the hero values if they are set, over calling `.getMember`. This means
-// in SSS mode we will always use the heroes if they exist, but in sync v2 mode these fields will
-// never be set and hence we will always do getMember lookups (at the right time as well).
-export type Hero = {
-    userId: string;
-    displayName?: string;
-    avatarUrl?: string;
-};
-
 export type RoomEventHandlerMap = {
     /**
      * Fires when the logged in user's membership in the room is updated.
@@ -376,6 +362,8 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
     // read by megolm via getter; boolean value - null indicates "use global value"
     private blacklistUnverifiedDevices?: boolean;
     private selfMembership?: Membership;
+    // A Hero is a stripped m.room.member event which contains the key renderable fields from the event.
+    // It is used in MSC4186 (Simplified Sliding Sync) as a replacement for the old 'summary' field.
     private heroes: Hero[] | null = null;
     // flags to stop logspam about missing m.room.create events
     private getTypeWarning = false;
@@ -958,8 +946,15 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         const nonFunctionalHeroes = this.heroes?.filter((h) => !functionalMembers.includes(h.userId));
         const hasHeroes = Array.isArray(nonFunctionalHeroes) && nonFunctionalHeroes.length;
         if (hasHeroes) {
-            // use first hero which exists
+            // use first hero that has a display name or avatar url, or whose user ID
+            // can be looked up as a member of the room
             for (const hero of nonFunctionalHeroes) {
+                // The old form of heroes simply contained the hero's user ID, which forced clients to then look up the
+                // m.room.member event in the current state. This is entirely decoupled in SSS. To ensure this
+                // works in a backwards compatible way, we will A) only set displayName/avatarUrl with server-provided
+                // values, B) always prefer the hero values if they are set, over calling `.getMember`. This means
+                // in SSS mode we will use the heroes if the display name or avatar URL fields are set, but in sync v2
+                // mode these fields will never be set and hence we will always do getMember lookups (at the right time as well).
                 if (!hero.displayName && !hero.avatarUrl) {
                     // attempt to look up renderable fields from the m.room.member event if it exists
                     const member = this.getMember(hero.userId);
@@ -1679,16 +1674,16 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
         return this.setUnreadNotificationCount(type, count);
     }
 
-    public setSummary(summary: IRoomSummary | IRoomSummaryMSC4186): void {
+    /**
+     * Takes either a legacy or MSC4186 room summary and updates the room with it.
+     * The summary will be converted to a legacy style summary in order to be emitted
+     * in the `RoomEvent.Summary` event.
+     *
+     * @param summary - The room summary to update the room with
+     */
+    public setSummary(summary: IRoomSummary | RoomSummaryMSC4186): void {
         // map heroes onto the MSC4186 form as that has more data
-        const heroes = summary["m.heroes"]?.map((h) => {
-            if (typeof h === "string") {
-                return {
-                    userId: h,
-                };
-            }
-            return h;
-        });
+        const heroes = summary["m.heroes"]?.map((h) => (typeof h === "string" ? { userId: h } : h));
         const joinedCount = summary["m.joined_member_count"];
         const invitedCount = summary["m.invited_member_count"];
         if (Number.isInteger(joinedCount)) {
@@ -1704,6 +1699,7 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
             });
         }
 
+        // Convert back to the legacy heroes format for the `RoomEvent.Summary` event.
         summary["m.heroes"] = heroes?.map((h) => h.userId);
 
         this.emit(RoomEvent.Summary, summary as IRoomSummary);
@@ -3540,6 +3536,9 @@ export class Room extends ReadReceipt<RoomEmittedEvents, RoomEventHandlerMap> {
                     inviteJoinCount--;
                     return;
                 }
+                // If the hero has a display name, use that.
+                // Otherwise, look their user ID up in the membership and use
+                // the name from there, or the user ID as a last resort.
                 if (hero.displayName) {
                     otherNames.push(hero.displayName);
                 } else {

src/sliding-sync-sdk.ts

@@ -383,7 +383,6 @@ export class SlidingSyncSdk {
     }
 
     private async onRoomData(roomId: string, roomData: MSC3575RoomData): Promise<void> {
-        const start = new Date().getTime();
         let room = this.client.store.getRoom(roomId);
         if (!room) {
             if (!roomData.initial) {
@@ -393,7 +392,6 @@ export class SlidingSyncSdk {
             room = _createAndReEmitRoom(this.client, roomId, this.opts);
         }
         await this.processRoomData(this.client, room!, roomData);
-        logger.log(`onRoomData ${roomId} took ${new Date().getTime() - start}ms`);
     }
 
     private onLifecycle(state: SlidingSyncState, resp: MSC3575SlidingSyncResponse | null, err?: Error): void {
@@ -402,7 +400,6 @@ export class SlidingSyncSdk {
         }
         switch (state) {
             case SlidingSyncState.Complete:
-                logger.log(`SlidingSyncState.Complete with ${Object.keys(resp?.rooms || []).length} rooms`);
                 this.purgeNotifications();
                 if (!resp) {
                     break;

src/sliding-sync.ts

@@ -82,10 +82,14 @@ export interface MSC3575SlidingSyncRequest {
     clientTimeout?: number;
 }
 
+/**
+ * New format of hero introduced in MSC4186 with display name and avatar URL
+ * in addition to just user_id
+ */
 export interface MSC4186Hero {
     user_id: string;
-    displayname: string;
-    avatar_url: string;
+    displayname?: string;
+    avatar_url?: string;
 }
 
 export interface MSC3575RoomData {